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Sample records for hard coatings evaluated

  1. Hard coatings

    International Nuclear Information System (INIS)

    Dan, J.P.; Boving, H.J.; Hintermann, H.E.

    1993-01-01

    Hard, wear resistant and low friction coatings are presently produced on a world-wide basis, by different processes such as electrochemical or electroless methods, spray technologies, thermochemical, CVD and PVD. Some of the most advanced processes, especially those dedicated to thin film depositions, basically belong to CVD or PVD technologies, and will be looked at in more detail. The hard coatings mainly consist of oxides, nitrides, carbides, borides or carbon. Over the years, many processes have been developed which are variations and/or combinations of the basic CVD and PVD methods. The main difference between these two families of deposition techniques is that the CVD is an elevated temperature process (≥ 700 C), while the PVD on the contrary, is rather a low temperature process (≤ 500 C); this of course influences the choice of substrates and properties of the coating/substrate systems. Fundamental aspects of the vapor phase deposition techniques and some of their influences on coating properties will be discussed, as well as the very important interactions between deposit and substrate: diffusions, internal stress, etc. Advantages and limitations of CVD and PVD respectively will briefly be reviewed and examples of applications of the layers will be given. Parallel to the development and permanent updating of surface modification technologies, an effort was made to create novel characterisation methods. A close look will be given to the coating adherence control by means of the scratch test, at the coating hardness measurement by means of nanoindentation, at the coating wear resistance by means of a pin-on-disc tribometer, and at the surface quality evaluation by Atomic Force Microscopy (AFM). Finally, main important trends will be highlighted. (orig.)

  2. Evaluating elastic modulus and strength of hard coatings by relative method

    International Nuclear Information System (INIS)

    Bao, Y.W.; Zhou, Y.C.; Bu, X.X.; Qiu, Y.

    2007-01-01

    A simple approach named relative method is developed for determining the elastic modulus and strength of hard coatings. Analytical relationship among the moduli of the film, the substrate, and the film/substrate system was derived based on bending model, from which the elastic modulus of the coating can be determined uniquely via the measured moduli of the samples before and after coating. Furthermore, the relationship between the strength of the films and the bending strength of the coated sample is derived, thus both the modulus and the strength of coating can be evaluated via traditional tests on coated samples. Mathematic expressions of those calculations were derived, respectively for rectangular beam samples with three types of coating configurations: single face coating, sandwich coating and around coating. Experimental results using various brittle coatings demonstrated the validity and convenience of this method

  3. Evaluating elastic modulus and strength of hard coatings by relative method

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Y.W. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); China Building Materials Academy, Beijing 100024 (China)], E-mail: ywbao@imr.ac.cn; Zhou, Y.C. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Bu, X.X. [China Building Materials Academy, Beijing 100024 (China); Qiu, Y. [China Building Materials Academy, Beijing 100024 (China)

    2007-06-15

    A simple approach named relative method is developed for determining the elastic modulus and strength of hard coatings. Analytical relationship among the moduli of the film, the substrate, and the film/substrate system was derived based on bending model, from which the elastic modulus of the coating can be determined uniquely via the measured moduli of the samples before and after coating. Furthermore, the relationship between the strength of the films and the bending strength of the coated sample is derived, thus both the modulus and the strength of coating can be evaluated via traditional tests on coated samples. Mathematic expressions of those calculations were derived, respectively for rectangular beam samples with three types of coating configurations: single face coating, sandwich coating and around coating. Experimental results using various brittle coatings demonstrated the validity and convenience of this method.

  4. Rock-hard coatings

    OpenAIRE

    Muller, M.

    2007-01-01

    Aircraft jet engines have to be able to withstand infernal conditions. Extreme heat and bitter cold tax coatings to the limit. Materials expert Dr Ir. Wim Sloof fits atoms together to develop rock-hard coatings. The latest invention in this field is known as ceramic matrix composites. Sloof has signed an agreement with a number of parties to investigate this material further.

  5. Rock-hard coatings

    NARCIS (Netherlands)

    Muller, M.

    2007-01-01

    Aircraft jet engines have to be able to withstand infernal conditions. Extreme heat and bitter cold tax coatings to the limit. Materials expert Dr Ir. Wim Sloof fits atoms together to develop rock-hard coatings. The latest invention in this field is known as ceramic matrix composites. Sloof has

  6. Electrodeposited Ni-B coatings: Formation and evaluation of hardness and wear resistance

    International Nuclear Information System (INIS)

    Krishnaveni, K.; Sankara Narayanan, T.S.N.; Seshadri, S.K.

    2006-01-01

    The formation of electrodeposited Ni-B alloy coatings using a dimethylamine borane (DMAB) modified Watt's nickel bath and evaluation of their structural characteristics, hardness and wear resistance are discussed. The boron content in the electrodeposited Ni-B alloy coating is determined by the ratio of rate of reduction of nickel and rate of decomposition of DMAB. The boron content of the electrodeposited Ni-B coating decreases as the current density increased from 0.4 to 4 A dm -2 . XRD diffraction pattern of electrodeposited Ni-B coatings in their as-plated condition exhibits the presence of Ni (1 1 1) (2 0 0) and (2 2 0) reflections with (1 1 1) texture. Heat treatment at 400 deg. C for 1 h has resulted in the formation of nickel boride phases, which results in an increase in hardness and wear resistance. The mechanism of wear in electrodeposited Ni-B coatings is intensive plastic deformation of the coating due to the ploughing action of the hard counter disk

  7. Zirconium nitride hard coatings

    International Nuclear Information System (INIS)

    Roman, Daiane; Amorim, Cintia Lugnani Gomes de; Soares, Gabriel Vieira; Figueroa, Carlos Alejandro; Baumvol, Israel Jacob Rabin; Basso, Rodrigo Leonardo de Oliveira

    2010-01-01

    Zirconium nitride (ZrN) nanometric films were deposited onto different substrates, in order to study the surface crystalline microstructure and also to investigate the electrochemical behavior to obtain a better composition that minimizes corrosion reactions. The coatings were produced by physical vapor deposition (PVD). The influence of the nitrogen partial pressure, deposition time and temperature over the surface properties was studied. Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and corrosion experiments were performed to characterize the ZrN hard coatings. The ZrN films properties and microstructure changes according to the deposition parameters. The corrosion resistance increases with temperature used in the films deposition. Corrosion tests show that ZrN coating deposited by PVD onto titanium substrate can improve the corrosion resistance. (author)

  8. Evaluation on machined surface of hardened stainless steel generated by hard turning using coated carbide tools with wiper geometry

    International Nuclear Information System (INIS)

    Noordin, M.Y.; Kurniawan, D.; Sharif, S.

    2007-01-01

    Hard turning has been explored to be the finish machining operation for parts made of hardened steel. Its feasibility is determined partially by the quality of the resulting machined surface. This study evaluates the surface integrity of martensitic stainless steel (48 HRC) resulting from hard turning using coated carbide tool with wiper geometry at various cutting speed and feed and compares to that obtained using coated carbide tool with conventional geometry. The wiper coated carbide tool is able to produce machined surface which is of finer finish (Ra is finer than 0.4 μm at most cutting parameters) and yet is similarly inducing only minor microstructural alteration compared to its conventional counterpart. From the view of the chip morphology where continuous type of chip is desired rather than sawtooth chip type, the wiper tool generates continuous chip at almost similar range of cutting parameters compared to the case when using conventional tool. Additionally, the use of wiper tool also induces the preferred compressive residual stress at the machined surface. (author)

  9. Induction surface hardening of hard coated steels

    DEFF Research Database (Denmark)

    Pantleon, Karen; Kessler, Olaf; Hoffmann, Franz

    1999-01-01

    The deposition of hard coatings with CVD-processes is commonly used to improve the wear resistance e.g. of tool steels in forming. The advantages of CVD are undisputed (high deposition rates with simple equipment, excellent coating properties). Nevertheless, the disadvantage of the CVD-process is......The deposition of hard coatings with CVD-processes is commonly used to improve the wear resistance e.g. of tool steels in forming. The advantages of CVD are undisputed (high deposition rates with simple equipment, excellent coating properties). Nevertheless, the disadvantage of the CVD...

  10. Analytical Modeling of Hard-Coating Cantilever Composite Plate considering the Material Nonlinearity of Hard Coating

    Directory of Open Access Journals (Sweden)

    Wei Sun

    2015-01-01

    Full Text Available Due to the material nonlinearity of hard coating, the coated structure produces the nonlinear dynamical behaviors of variable stiffness and damping, which make the modeling of hard-coating composite structure become a challenging task. In this study, the polynomial was adopted to characterize this material nonlinearity and an analytical modeling method was developed for the hard-coating composite plate. Firstly, to relate the hard-coating material parameters obtained by test and the analytical model, the expression of equivalent strain of composite plate was derived. Then, the analytical model of hard-coating composite plate was created by energy method considering the material nonlinearity of hard coating. Next, using the Newton-Raphson method to solve the vibration response and resonant frequencies of composite plate and a specific calculation procedure was also proposed. Finally, a cantilever plate coated with MgO + Al2O3 hard coating was chosen as study case; the vibration response and resonant frequencies of composite plate were calculated using the proposed method. The calculation results were compared with the experiment and general linear calculation, and the correctness of the created model was verified. The study shows the proposed method can still maintain an acceptable precision when the material nonlinearity of hard coating is stronger.

  11. Analysis of Hard Thin Film Coating

    Science.gov (United States)

    Shen, Dashen

    1998-01-01

    MSFC is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using electron cyclotron resonance chemical vapor deposition (ECRCVD) to deposit hard thin film an stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  12. Thermal spray coatings replace hard chrome

    International Nuclear Information System (INIS)

    Schroeder, M.; Unger, R.

    1997-01-01

    Hard chrome plating provides good wear and erosion resistance, as well as good corrosion protection and fine surface finishes. Until a few years ago, it could also be applied at a reasonable cost. However, because of the many environmental and financial sanctions that have been imposed on the process over the past several years, cost has been on a consistent upward trend, and is projected to continue to escalate. Therefore, it is very important to find a coating or a process that offers the same characteristics as hard chrome plating, but without the consequent risks. This article lists the benefits and limitations of hard chrome plating, and describes the performance of two thermal spray coatings (tungsten carbide and chromium carbide) that compared favorably with hard chrome plating in a series of tests. It also lists three criteria to determine whether plasma spray or hard chrome plating should be selected

  13. Induction surface hardening of hard coated steels

    Energy Technology Data Exchange (ETDEWEB)

    Pantleon, K.; Kessler, O.; Hoffann, F.; Mayr, P. [Stiftung Inst. fuer Werkstofftechnik, Bremen (Germany)

    1999-11-01

    The properties of hard coatings deposited using CVD processes are usually excellent. However, high deposition temperatures negatively influence the substrate properties, especially in the case of low alloyed steels. Therefore, a subsequent heat treatment is necessary to restore the properties of steel substrates. Here, induction surface hardening is used as a method of heat treatment after the deposition of TiN hard coatings on AISI 4140 (DIN42CrMo4) substrates. The influences of the heat treatment on both the coating and the substrate properties are discussed in relation to the parameters of induction heating. Thereby, the heating time, heating atmosphere and the power input into the coating-substrate compounds are varied. As a result of induction surface hardening, the properties of the substrates are improved without losing good coating properties. High hardness values in the substrate near the interface allow the AISI 4140 substrates to support TiN hard coatings very well. Consequently, higher critical loads are measured in scratch tests after the heat treatment. Also, compressive residual stresses in the substrate are generated. In addition, only a very low distortion appears. (orig.)

  14. Hard Coat Layers by PE-CVD Process for the Top Surface of Touch Panel

    International Nuclear Information System (INIS)

    Okunishi, T; Sato, N; Yazawa, K

    2013-01-01

    In order to protect surface from damages, the high pencil hardness and the high abrasion resistance are required for the hard coat layers on polyethylene telephthalate (PET) films for the application of touch panel surface. We have already found that the UV-curing-hard-coat-polymer (UHP) coated PET films show the poor abrasion resistance, while they have the high pencil hardness. It reveals that the abrasion resistance of hard coat layers of the UHP is not simply dependent on the pencil hardness. In this work, we have studied to improve the abrasion resistance of SiOC films as hard coat layers, which were formed by PE-CVD process on UHP coated PET. The abrasion resistance was evaluated by Taber abrasion test. PE-CVD hard coat layers which formed on UHP coater PET films have showed the better abrasion resistance and have the possibility of substitution to the thin glass sheets for touch panel application.

  15. Erosion testing of hard materials and coatings

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.

    2005-04-29

    Erosion is the process by which unconstrained particles, usually hard, impact a surface, creating damage that leads to material removal and component failure. These particles are usually very small and entrained in fluid of some type, typically air. The damage that occurs as a result of erosion depends on the size of the particles, their physical characteristics, the velocity of the particle/fluid stream, and their angle of impact on the surface of interest. This talk will discuss the basics of jet erosion testing of hard materials, composites and coatings. The standard test methods will be discussed as well as alternative approaches to determining the erosion rate of materials. The damage that occurs will be characterized in genera1 terms, and examples will be presented for the erosion behavior of hard materials and coatings (both thick and thin).

  16. Nanolaminated TiN/Mo2N hard multilayer coatings

    International Nuclear Information System (INIS)

    Martev, I N; Dechev, D A; Ivanov, N P; Uzunov, T S D; Kashchieva, E P

    2010-01-01

    The paper presents results on the synthesis of hard multilayer coatings consisting of titanium nitride and molybdenum nitride thin films with thickness of several nm. The TiN and Mo 2 N films were successively deposited by reactive DC magnetron sputtering. These multilayer structures were investigated by Auger electron spectroscopy (AES), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), cross-section scanning electron microscopy (CSSEM) and cross-section electron probe microanalysis (CSEPMA). The mechanical properties of the multilayer coatings, namely, hardness, Young's modulus and the coefficient of plastic deformation were measured. The adhesion was evaluated by the Rockwell-C-impact test. Coatings with different total thickness were examined with respect to adhesion to substrates of tool materials.

  17. Evaluation of microstructure and micro-hardness of 410L SS coatings fabricated using laser assisted cold spraying: process development

    CSIR Research Space (South Africa)

    Mathebula, TE

    2014-11-01

    Full Text Available , contaminating and erosive environments which accelerate the degradation of these components. Surface coatings are generally used to protect and prolong the lifetime of the parts. Laser Assisted Cold Spray (LACS) is a relatively new surface coating process which...

  18. Effect of bond coat and preheat on the microstructure, hardness, and porosity of flame sprayed tungsten carbide coatings

    Science.gov (United States)

    Winarto, Winarto; Sofyan, Nofrijon; Rooscote, Didi

    2017-06-01

    Thermally sprayed coatings are used to improve the surface properties of tool steel materials. Bond coatings are commonly used as intermediate layers deposited on steel substrates (i.e. H13 tool steel) before the top coat is applied in order to enhance a number of critical performance criteria including adhesion of a barrier coating, limiting atomic migration of the base metal, and corrosion resistance. This paper presents the experimental results regarding the effect of nickel bond coat and preheats temperatures (i.e. 200°C, 300°C and 400°C) on microstructure, hardness, and porosity of tungsten carbide coatings sprayed by flame thermal coating. Micro-hardness, porosity and microstructure of tungsten carbide coatings are evaluated by using micro-hardness testing, optical microscopy, scanning electron microscopy, and X-ray diffraction. The results show that nickel bond coatings reduce the susceptibility of micro crack formation at the bonding area interfaces. The percentage of porosity level on the tungsten carbide coatings with nickel bond coat decreases from 5.36 % to 2.78% with the increase of preheat temperature of the steel substrate of H13 from 200°C to 400°C. The optimum hardness of tungsten carbide coatings is 1717 HVN in average resulted from the preheat temperature of 300°C.

  19. Oxidation study of Cr-Ru hard coatings

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yung-I, E-mail: yichen@mail.ntou.edu.tw; Kuo, Yu-Chu; Chen, Sin-Min

    2012-01-01

    Cr-Ru alloy coatings with Cr content ranging from 47 to 83 at.% were deposited at 400 Degree-Sign C by direct current magnetron co-sputtering with a Ti interlayer on silicon substrates. With a total input power of 300 W, the Cr content in the Cr-Ru coatings increased linearly with the increasing input power of Cr. The intermetallic compound phase Cr{sub 2}Ru with columnar structure was identified for the as-deposited Cr{sub 56}Ru{sub 44} and Cr{sub 65}Ru{sub 35} coatings, resulting in an increase of hardness up to 15-16 GPa. To evaluate the performance of Cr-Ru coatings as a protective coating on glass molding dies, the annealing treatment was conducted at 600 Degree-Sign C in a 50 ppm O{sub 2}-N{sub 2} atmosphere. The outward diffusion and preferential oxidization of Cr in the Cr-Ru coatings resulted in the variations of the crystalline structure, chemical composition distribution, and surface hardness after annealing. X-ray diffraction and transmission electron microscopy (TEM) proved that an oxide scale consisting of Cr{sub 2}O{sub 3} formed on the free surface. Scanning electron microscopy and TEM observed the surface morphology and structural variation. The chemical composition depth profiles were analyzed by Auger electron microscopy, verifying the presence of a Cr-depleted zone beneath the oxide scale. The hardness of Cr{sub 56}Ru{sub 44} and Cr{sub 65}Ru{sub 35} coatings decreased to 11-12 GPa after annealing, accompanied by the replacement of the Cr{sub 2}Ru phase by the Ru phase. - Highlights: Black-Right-Pointing-Pointer We prepared crystalline Cr-Ru alloy coatings by direct current magnetron sputtering. Black-Right-Pointing-Pointer Cr-Ru coatings were annealed at 600 Degree-Sign C for 2 h in a 50 ppm O{sub 2}-N{sub 2} atmosphere. Black-Right-Pointing-Pointer Cr diffused outwardly and oxidized to form a stable and protective oxide scale. Black-Right-Pointing-Pointer The original columnar grains recrystallized to polycrystalline grains.

  20. Raman microscopic studies of PVD deposited hard ceramic coatings

    International Nuclear Information System (INIS)

    Constable, C.P.

    2000-01-01

    PVD hard ceramic coatings grown via the combined cathodic arc/unbalance magnetron deposition process were studied using Raman microscopy. Characteristic spectra from binary, multicomponent, multilayered and superlattice coatings were acquired to gain knowledge of the solid-state physics associated with Raman scattering from polycrystalline PVD coatings and to compile a comprehensive spectral database. Defect-induced first order scattering mechanisms were observed which gave rise to two pronounced groups of bands related to the acoustical (150- 300cm -1 ) and optical (400-7 50cm -1 ) parts of the phonon spectrum. Evidence was gathered to support the theory that the optic modes were mainly due to the vibrations of the lighter elements and the acoustic modes due to the vibrations of the heavier elements within the lattice. A study into the deformation and disordering on the Raman spectral bands of PVD coatings was performed. TiAIN and TiZrN coatings were intentionally damaged via scratching methods. These scratches were then analysed by Raman mapping, both across and along, and a detailed spectral interpretation performed. Band broadening occurred which was related to 'phonon relaxation mechanisms' as a direct result of the breaking up of coating grains resulting in a larger proportion of grain boundaries per-unit-volume. A direct correlation of the amount of damage with band width was observed. Band shifts were also found to occur which were due to the stresses caused by the scratching process. These shifts were found to be the largest at the edges of scratches. The Raman mapping of 'droplets', a defect inherent to PVD deposition processes, found that higher compressive stresses and large amounts of disorder occurred for coating growth onto droplets. Strategies designed to evaluate the ability of Raman microscopy to monitor the extent of real wear on cutting tools were evaluated. The removal of a coating layer and subsequent detection of a base layer proved

  1. Application of hard coatings for blanking and piercing tools

    DEFF Research Database (Denmark)

    Podgornik, B.; Zajec, B.; Bay, Niels

    2011-01-01

    The aim of the present investigation was to examine the possibility of reducing lubrication and replacing expensive tungsten carbide material in blanking/piercing through introduction of hard tool coatings. Results show that hard PVD coatings can be successfully used in blanking/piercing...... critical value under dry friction conditions and leads to tool failure. Therefore, at present oxidation and temperature resistant hard coatings can give improved wear resistance of stamping tools, but elimination of lubricants in blanking and piercing processes is still not feasible....

  2. Highly Damping Hard Coatings for Protection of Titanium Blades

    National Research Council Canada - National Science Library

    Movchan, Boris A; Ustinov, Anatolii I

    2005-01-01

    Sn-Cr-MgO system is used as an example to show the basic capability to produce by EBPVD protective metal-ceramic coatings with a high adhesion strength, high values of hardness and damping capacity...

  3. A novel method to predict the highest hardness of plasma sprayed coating without micro-defects

    Science.gov (United States)

    Zhuo, Yukun; Ye, Fuxing; Wang, Feng

    2018-04-01

    The plasma sprayed coatings are stacked by splats, which are regarded generally as the elementary units of coating. Many researchers have focused on the morphology and formation mechanism of splat. However, a novel method to predict the highest hardness of plasma sprayed coating without micro-defects is proposed according to the nanohardness of splat in this paper. The effectiveness of this novel method was examined by experiments. Firstly, the microstructure of splats and coating, meanwhile the 3D topography of the splats were observed by SEM (SU1510) and video microscope (VHX-2000). Secondly, the nanohardness of splats was evaluated by nanoindentation (NHT) in order to be compared with microhardness of coating measured by microhardness tester (HV-1000A). The results show that the nanohardness of splats with diameter of 70 μm, 100 μm and 140 μm were in the scope of 11∼12 GPa while the microhardness of coating were in the range of 8∼9 GPa. Because the splats had not micro-defects such as pores and cracks in the nanohardness evaluated nano-zone, the nanohardness of the splats can be utilized to predict the highest hardness of coating without micro-defects. This method indicates the maximum of sprayed coating hardness and will reduce the test number to get high hardness coating for better wear resistance.

  4. Comparative metallurgical study of thick hard coatings without cobalt

    International Nuclear Information System (INIS)

    Clemendot, F.; Van Duysen, J.C.; Champredonde, J.

    1992-07-01

    Wear and corrosion of stellite type hard coatings for valves of the PWR primary system raise important problems of contamination. Substitution of these alloys by cobalt-free hard coatings (Colmonoy 4 and 4.26, Cenium 36) should allow to reduce this contamination. A comparative study (chemical, mechanical, thermal, metallurgical), as well as a corrosion study of these coatings were carried out. The results of this characterization show that none of the studied products has globally characteristics as good as those of grade 6 Stellite currently in service

  5. LARGE AREA FILTERED ARC DEPOSITION OF CARBON AND BORON BASED HARD COATINGS

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Rabi S.

    2003-12-05

    This document is a final report covering work performed under Contract No. DE-FG02-99ER82911 from the Department of Energy under a SBIR Phase II Program. Wear resistant, hard coatings can play a vital role in many engineering applications. The primary goal of this project was to develop coatings containing boron and carbon with hardness greater than 30 GPa and evaluate these coatings for machining applications. UES has developed a number of carbon and boron containing coatings with hardness in the range of 34 to 65 GPa using a combination of filtered cathodic arc and magnetron sputtering. The boron containing coatings were based on TiB2, TiBN, and TiBCN, while the carbon containing coatings ere TiC+C and hydrogen free diamond-like-carbon. Machining tests were performed with single and multilayer coated tools. The turning and milling tests were run at TechSolve Inc., under a subcontract at Ohio State University. Significant increases in tool lives were realized in end milling of H-13 die steel (8X) and titanium alloy (80%) using the TiBN coating. A multilayer TiBN/TiN performed the best in end-milling of highly abrasive Al-Si alloys. A 40% increase in life over the TiAlN benchmark coating was found. Further evaluations of these coatings with commercialization partners are currently in progress.

  6. Hardness and electrochemical behavior of ceramic coatings on Inconel

    Directory of Open Access Journals (Sweden)

    C. SUJAYA

    2012-03-01

    Full Text Available Thin films of ceramic materials like alumina and silicon carbide are deposited on Inconel substrate by pulsed laser deposition technique using Q-switched Nd: YAG laser. Deposited films are characterized using UV-visible spectrophotometry and X-ray diffraction. Composite microhardness of ceramic coated Inconel system is measured using Knoop indenter and its film hardness is separated using a mathematical model based on area-law of mixture. It is then compared with values obtained using nanoindentation method. Film hardness of the ceramic coating is found to be high compared to the substrates. Corrosion behavior of substrates after ceramic coating is studied in 3.5% NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy measurements. The Nyquist and the Bode plots obtained from the EIS data are fitted by appropriate equivalent circuits. The pore resistance, the charge transfer resistance, the coating capacitance and the double layer capacitance of the coatings are obtained from the equivalent circuit. Experimental results show an increase in corrosion resistance of Inconel after ceramic coating. Alumina coated Inconel showed higher corrosion resistance than silicon carbide coated Inconel. After the corrosion testing, the surface topography of the uncoated and the coated systems are examined by scanning electron microscopy.

  7. Microstructures, hardness and bioactivity of hydroxyapatite coatings

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2014-10-01

    Full Text Available Hydroxyapatite (HAP) coatings on bioinert metals such as Ti–6Al–4V are necessary for biomedical applications. Together, HAP and Ti–6Al–4V are biocompatible and bioactive. The challenges of depositing HAP on Ti–6Al–4V with traditional thermal...

  8. Evaluation of hard fossil fuel

    International Nuclear Information System (INIS)

    Zivkovic, S.; Nuic, J.

    1999-01-01

    Because of its inexhaustible supplies hard fossil fuel will represent the pillar of the power systems of the 21st century. Only high-calorie fossil fuels have the market value and participate in the world trade. Low-calorie fossil fuels ((brown coal and lignite) are fuels spent on the spot and their value is indirectly expressed through manufactured kWh. For the purpose of determining the real value of a tonne of low-calorie coal, the criteria that help in establishing the value of a tonne of hard coal have to be corrected and thus evaluated and assessed at the market. (author)

  9. Microindentation hardness testing of coatings: techniques and interpretation of data

    Science.gov (United States)

    Blau, P. J.

    1986-09-01

    This paper addresses the problems and promises of micro-indentation testing of thin solid films. It has discussed basic penetration hardness testing philosophy, the peculiarities of low load-shallow penetration tests of uncoated metals, and it has compared coated with uncoated behavior so that some of the unique responses of coatings can be distinguished from typical hardness versus load behavior. As the uses of thin solid coatings with technological interest continue to proliferate, microindentation testing methodology will increasingly be challenged to provide useful tools for their characterization. The understanding of microindentation response must go hand-in-hand with machine design so that the capability of measurement precision does not outstrip our abilities to interpret test results in a meaningful way.

  10. Tough-coated hard powders for hardmetals of novel properties

    International Nuclear Information System (INIS)

    Toth, R.E.; Smid, I.; Kladler, G.; Korb, G.; Sherman, A.; Ettmayer, P.

    2001-01-01

    The properties and performance of conventional materials and composites are constrained by solubility limits, diffusion coefficients, and compatibility of physical and chemical constituent properties in their phase equilibria. To escape these limits, ingenious ways of combining strength, toughness, and wear resistance by way of various coatings and laminations have been devised. These coated tools are systematically discarded after only about 10 % of their wear tolerance has been used. Tough-coated hard powders (TCHP), patented by EnDurAloy (USA), are hard refractory particles CVD coated with nanolayers of WC and Co. Consolidation of TCHP creates an engineered homogeneous cellular structure whose interconnected tough WC-Co 'shells' each contain a wear-resistant core (e.g., TiN). In TCHP's, the coating is throughout the tool, not only on the surface, combining the strength, heat resistance, and toughness of cemented carbides with the chemical and abrasion wear resistance of harder materials. As wear progresses, new wear-resistant material continuously replaces the working surfaces and edges of the tool until its geometry reaches its maximum limits. TCHP tools are then reusable many times. Specific coating and consolidation processes, characterization of compacts, and test comparisons with conventional materials are discussed. (author)

  11. An investigation into the mechanical and tribological properties of plasma electrolytic oxidation and hard-anodized coatings on 6082 aluminum alloy

    International Nuclear Information System (INIS)

    Malayoglu, Ugur; Tekin, Kadir C.; Malayoglu, Ufuk; Shrestha, Suman

    2011-01-01

    Highlights: → Mechanical properties of PEO and anodised coatings were studied using ultra-micro hardness tester. → Elastic modulus and hardness of the PEO coating were found much higher than those of the anodised coating. → Improved sliding wear of PEO coating is due to presence of hard α and γ-Al 2 O 3 phases. - Abstract: A ceramic coating on AA6082 aluminum alloy prepared by plasma electrolytic oxidation (PEO) has been studied and compared against a sulphuric acid hard-anodized coating on the same alloy. Surface morphology and microstructures of the coatings have been examined by scanning electron microscopy. X-ray diffraction is used to determine the phase composition of the coatings. The adhesion strength of the coatings has been evaluated using a scratch test method. The coating's mechanical properties such elastic modulus and hardness data have been generated using a dynamic ultra-microhardness tester. Sliding wear tests with different loading rates are performed on the coatings in order to assess their wear resistance. Test results show that the PEO treated samples exhibit significantly better mechanical properties compared to hard anodized samples. The elastic modulus and hardness of the PEO coating are 2-3 times greater than of the hard anodized coating and subsequently, an improved wear resistance of the PEO coating has been achieved. The mechanical properties of the coatings and their relations to their tribological performance are discussed.

  12. Selection of boron based tribological hard coatings using multi-criteria decision making methods

    International Nuclear Information System (INIS)

    Çalışkan, Halil

    2013-01-01

    Highlights: • Boron based coating selection problem for cutting tools was solved. • EXPROM2, TOPSIS and VIKOR methods were used for ranking the alternative materials. • The best coatings for cutting tool were selected as TiBN and TiSiBN. • The ranking results are in good agreement with cutting test results in literature. - Abstract: Mechanical and tribological properties of hard coatings can be enhanced using boron as alloying element. Therefore, multicomponent nanostructured boron based hard coatings are deposited on cutting tools by different methods at different parameters. Different mechanical and tribological properties are obtained after deposition, and it is a difficult task to select the best coating material. In this paper, therefore, a systematic evaluation model was proposed to tackle the difficulty of the material selection with specific properties among a set of available alternatives. The alternatives consist of multicomponent nanostructured TiBN, TiCrBN, TiSiBN and TiAlSiBN coatings deposited by magnetron sputtering and ion implantation assisted magnetron sputtering at different parameters. The alternative coating materials were ranked by using three multi-criteria decision-making (MCDM) methods, i.e. EXPROM2 (preference ranking organization method for enrichment evaluation), TOPSIS (technique for order performance by similarity to ideal solution) and VIKOR (VIšekriterijumsko KOmpromisno Rangiranje), in order to determine the best coating material for cutting tools. Hardness (H), Young’s modulus (E), elastic recovery, friction coefficient, critical load, H/E and H 3 /E 2 ratios were considered as material selection criteria. In order to determine the importance weights of the evaluation criteria, a compromised weighting method, which composes of the analytic hierarchy process and Entropy methods, were used. The ranking results showed that TiBN and TiSiBN coatings deposited at given parameters are the best coatings for cutting tools

  13. Corrosion performance of some titanium-based hard coatings

    International Nuclear Information System (INIS)

    Matthes, B.; Broszeit, E.; Aromaa, J.; Ronkainen, H.; Hannula, S.P.; Leyland, A.; Matthews, A.

    1991-01-01

    Tools and machine parts which could benefit from wear-resistant titanium-based hard films are often subject to corrosive environments. Physically vapour-deposited coatings frequently exhibit porosity and even small defects, which can cause rapid local corrosion of the substrate material; there is therefore a requirement for dense and chemically inert coatings. This paper presents corrosion data for titanium-based hard coatings such as TiN, (Ti, Al)N, Ti(B, N) and TiB 2 and also for multilayered structures where additional aluminium-based insulating surface layers (AlN and Al 2 O 3 ) were deposited. The corrosion resistance and porosity of the films were analysed by electrochemical techniques. The degree of metallic bonding can play a significant role in influencing the corrosion resistance of refractory transition-metal-based ceramic coatings. Here we demonstrate that, under potentiodynamic corrosion test conditions, resistance to corrosive attack was relatively poor for TiB 2 , better for (Ti, Al)N and Ti(B, N) and best for TiN. It is also shown that applying the additional protective aluminium-based insulating surface layers on the coating can further improve corrosion resistance. (orig.)

  14. Structure, properties and wear behaviour of multilayer coatings consisting of metallic and covalent hard materials, prepared by magnetron sputtering

    International Nuclear Information System (INIS)

    Schier, V.

    1995-12-01

    Novel multilayer coatings with metallic and covalent layer materials were prepared by magnetron sputtering and characterised concerning structure, properties and application behaviour. At first single layer coatings were deposited for the determination of the material properties. To evaluate relations between structure and properties of the multilayer coatings, different multilayer concepts were realised: - coatings consisting of at most 7 layers of metallic hard materials, - 100-layer coatings consisting of metallic and covalent hard materials, - TiN-TiC multilayer coatings with different numbers of layers (between 10 and 1000), - 150-layer coatings, based on TiN-TiC multilayers, with thin ( 4 C, AlN, SiC, a:C, Si 3 N 4 , SiAlON). X-rays and electron microscopic analysis indicate in spite of nonstoichiometric compositions single phase crystalline structures for nonreactively and reactively sputtered metastable single layer Ti(B,C)-, Ti(B,N)- and Ti(B,C,N)-coatings. These single layer coatings show excellent mechanical properties (e.g. hardness values up to 6000 HV0,05), caused by lattice stresses as well as by atomic bonding conditions similar to those in c:BN and B 4 C. The good tribological properties shown in pin-on-disk-tests can be attributed to the very high hardness of the coatings. The coatings consisting of at most 7 layers of metallic hard materials show good results mainly for the cutting of steel Ck45, due to the improved mechanical properties (e.g. hardness, toughness) of the multilayers compared to the single layer coatings. This improvement is caused by inserting the hard layer materials and the coherent reinforcement of the coatings. (orig.)

  15. Cover layer technology and a new hard coat for cartridge-free Blu-ray disc

    Science.gov (United States)

    Kang, Tae-Sik; Han, Mi Young; Lee, Seong-Keun; Jang, Sung Hoon; Hong, Young Jun; Seo, Hun; Lee, Chang-Ho

    2004-09-01

    Spin coating method for cover layer of Blu-ray Disc (BD) has been studied and a new hard coat resin including antifouling property has been developed. A vacuum chuck was newly designed to minimize the ski-jump effect. 3 mm hard coat layer was stacked onto the 97 mm cover layer by spin coating method.

  16. Hard coatings on magnesium alloys by sputter deposition using a pulsed d.c. bias voltage

    Energy Technology Data Exchange (ETDEWEB)

    Reiners, G. [Bundesanstalt fuer Materialforschung und -pruefung, Berlin (Germany); Griepentrog, M. [Bundesanstalt fuer Materialforschung und -pruefung, Berlin (Germany)

    1995-12-01

    An increasing use of magnesium-based light-metal alloys for various industrial applications was predicted in different technological studies. Companies in different branches have developed machine parts made of magnesium alloys (e.g. cars, car engines, sewing and knitting machines). Hence, this work was started to evaluate the ability of hard coatings obtained by physical vapour deposition (PVD) in combination with coatings obtained by electrochemical deposition to protect magnesium alloys against wear and corrosion. TiN hard coatings were deposited onto magnesium alloys by unbalanced magnetron sputter deposition. A bipolar pulsed d.c. bias voltage was used to limit substrate temperatures to 180 C during deposition without considerable loss of microhardness and adhesion. Adhesion, hardness and load-carrying capacity of TiN coatings deposited directly onto magnesium alloys are compared with the corresponding values of TiN coatings deposited onto substrates which had been coated electroless with an Ni-P alloy interlayer prior to the PVD. (orig.)

  17. Quantitative Analysis of Electroplated Nickel Coating on Hard Metal

    Directory of Open Access Journals (Sweden)

    Hassan A. Wahab

    2013-01-01

    Full Text Available Electroplated nickel coating on cemented carbide is a potential pretreatment technique for providing an interlayer prior to diamond deposition on the hard metal substrate. The electroplated nickel coating is expected to be of high quality, for example, indicated by having adequate thickness and uniformity. Electroplating parameters should be set accordingly for this purpose. In this study, the gap distances between the electrodes and duration of electroplating process are the investigated variables. Their effect on the coating thickness and uniformity was analyzed and quantified using design of experiment. The nickel deposition was carried out by electroplating in a standard Watt’s solution keeping other plating parameters (current: 0.1 Amp, electric potential: 1.0 V, and pH: 3.5 constant. The gap distance between anode and cathode varied at 5, 10, and 15 mm, while the plating time was 10, 20, and 30 minutes. Coating thickness was found to be proportional to the plating time and inversely proportional to the electrode gap distance, while the uniformity tends to improve at a large electrode gap. Empirical models of both coating thickness and uniformity were developed within the ranges of the gap distance and plating time settings, and an optimized solution was determined using these models.

  18. Tribological and Wear Performance of Nanocomposite PVD Hard Coatings Deposited on Aluminum Die Casting Tool

    Directory of Open Access Journals (Sweden)

    Jose Mario Paiva

    2018-02-01

    Full Text Available In the aluminum die casting process, erosion, corrosion, soldering, and die sticking have a significant influence on tool life and product quality. A number of coatings such as TiN, CrN, and (Cr,AlN deposited by physical vapor deposition (PVD have been employed to act as protective coatings due to their high hardness and chemical stability. In this study, the wear performance of two nanocomposite AlTiN and AlCrN coatings with different structures were evaluated. These coatings were deposited on aluminum die casting mold tool substrates (AISI H13 hot work steel by PVD using pulsed cathodic arc evaporation, equipped with three lateral arc-rotating cathodes (LARC and one central rotating cathode (CERC. The research was performed in two stages: in the first stage, the outlined coatings were characterized regarding their chemical composition, morphology, and structure using glow discharge optical emission spectroscopy (GDOES, scanning electron microscopy (SEM, and X-ray diffraction (XRD, respectively. Surface morphology and mechanical properties were evaluated by atomic force microscopy (AFM and nanoindentation. The coating adhesion was studied using Mersedes test and scratch testing. During the second stage, industrial tests were carried out for coated die casting molds. In parallel, tribological tests were also performed in order to determine if a correlation between laboratory and industrial tests can be drawn. All of the results were compared with a benchmark monolayer AlCrN coating. The data obtained show that the best performance was achieved for the AlCrN/Si3N4 nanocomposite coating that displays an optimum combination of hardness, adhesion, soldering behavior, oxidation resistance, and stress state. These characteristics are essential for improving the die mold service life. Therefore, this coating emerges as a novelty to be used to protect aluminum die casting molds.

  19. Tribological and Wear Performance of Nanocomposite PVD Hard Coatings Deposited on Aluminum Die Casting Tool.

    Science.gov (United States)

    Paiva, Jose Mario; Fox-Rabinovich, German; Locks Junior, Edinei; Stolf, Pietro; Seid Ahmed, Yassmin; Matos Martins, Marcelo; Bork, Carlos; Veldhuis, Stephen

    2018-02-28

    In the aluminum die casting process, erosion, corrosion, soldering, and die sticking have a significant influence on tool life and product quality. A number of coatings such as TiN, CrN, and (Cr,Al)N deposited by physical vapor deposition (PVD) have been employed to act as protective coatings due to their high hardness and chemical stability. In this study, the wear performance of two nanocomposite AlTiN and AlCrN coatings with different structures were evaluated. These coatings were deposited on aluminum die casting mold tool substrates (AISI H13 hot work steel) by PVD using pulsed cathodic arc evaporation, equipped with three lateral arc-rotating cathodes (LARC) and one central rotating cathode (CERC). The research was performed in two stages: in the first stage, the outlined coatings were characterized regarding their chemical composition, morphology, and structure using glow discharge optical emission spectroscopy (GDOES), scanning electron microscopy (SEM), and X-ray diffraction (XRD), respectively. Surface morphology and mechanical properties were evaluated by atomic force microscopy (AFM) and nanoindentation. The coating adhesion was studied using Mersedes test and scratch testing. During the second stage, industrial tests were carried out for coated die casting molds. In parallel, tribological tests were also performed in order to determine if a correlation between laboratory and industrial tests can be drawn. All of the results were compared with a benchmark monolayer AlCrN coating. The data obtained show that the best performance was achieved for the AlCrN/Si₃N₄ nanocomposite coating that displays an optimum combination of hardness, adhesion, soldering behavior, oxidation resistance, and stress state. These characteristics are essential for improving the die mold service life. Therefore, this coating emerges as a novelty to be used to protect aluminum die casting molds.

  20. Diamond-like carbon coatings enhance the hardness and resilience of bearing surfaces for use in joint arthroplasty.

    Science.gov (United States)

    Roy, M E; Whiteside, L A; Xu, J; Katerberg, B J

    2010-04-01

    The purpose of this study was to evaluate the potential of a hard diamond-like carbon (DLC) coating to enhance the hardness and resilience of a bearing surface in joint replacement. The greater hardness of a magnesium-stabilized zirconium (Mg-PSZ) substrate was expected to provide a harder coating-substrate composite microhardness than the cobalt-chromium alloy (CoCr) also used in arthroplasty. Three femoral heads of each type (CoCr, Mg-PSZ, DLC-CoCr and DLC-Mg-PSZ) were examined. Baseline (non-coated) and composite coating/substrate hardness was measured by Vickers microhardness tests, while nanoindentation tests measured the hardness and elastic modulus of the DLC coating independent of the Mg-PSZ and CoCr substrates. Non-coated Mg-PSZ heads were considerably harder than non-coated CoCr heads, while DLC coating greatly increased the microhardness of the CoCr and Mg-PSZ substrates. On the nanoscale the non-coated heads were much harder than on the microscale, with CoCr exhibiting twice as much plastic deformation as Mg-PSZ. The mechanical properties of the DLC coatings were not significantly different for both the CoCr and Mg-PSZ substrates, producing similar moduli of resilience and plastic resistance ratios. DLC coatings greatly increased hardness on both the micro and nano levels and significantly improved resilience and resistance to plastic deformation compared with non-coated heads. Because Mg-PSZ allows less plastic deformation than CoCr and provides a greater composite microhardness, DLC-Mg-PSZ will likely be more durable for use as a bearing surface in vivo. Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Hardness and Elastic Modulus of Titanium Nitride Coatings Prepared by Pirac Method

    Science.gov (United States)

    Wu, Siyuan; Wu, Shoujun; Zhang, Guoyun; Zhang, Weiguo

    In the present work, hardness and elastic modulus of a titanium nitride coatings prepared on Ti6Al4V by powder immersion reaction-assisted coating (PIRAC) are tested and comparatively studied with a physical vapor deposition (PVD) TiN coating. Surface hardness of the PIRAC coatings is about 11GPa, much lower than that of PVD coating of 22GPa. The hardness distribution profile from surface to substrate of the PVD coatings is steeply decreased from ˜22GPa to ˜4.5GPa of the Ti6Al4V substrate. The PIRAC coatings show a gradually decreasing hardness distribution profile. Elastic modulus of the PVD coating is about 426GPa. The PIRAC coatings show adjustable elastic modulus. Elastic modulus of the PIRAC coatings prepared at 750∘C for 24h and that at 800∘C for 8h is about 234 and 293GPa, respectively.

  2. Investigation of Plasma Spray Coatings as an Alternative to Hard Chrome Plating on Internal Surfaces

    National Research Council Canada - National Science Library

    Legg, Keith O; Sartwell, Bruce D; Legoux, Jean-Gabriel; Nestler, Montia; Dambra, Christopher; Wang, Daming; Quets, John; Natishan, Paul; Bretz, Philip; Devereaux, Jon

    2006-01-01

    .... This document constitutes the final report on an investigation of deposition of coatings using miniature plasma spray guns that could replace hard chromium on internal surfaces where conventional...

  3. Promising Hard Carbon Coatings on Cu Substrates: Corrosion and Tribological Performance with Theoretical Aspect

    Science.gov (United States)

    Kumar, A. Madhan; Babu, R. Suresh; Obot, I. B.; Adesina, Akeem Yusuf; Ibrahim, Ahmed; de Barros, A. L. F.

    2018-05-01

    Protecting the surface of metals and alloys against corrosion and wear is of abundant importance owing to their widespread applications. In the present work, we report the improved anticorrosion and tribo-mechanical performance of copper (Cu) by a hard carbon (HC) coating synthesized in different pyrolysis temperature. Structural and surface characterization with roughness measurements was systematically investigated using various techniques. Effect of pyrolysis temperature on the corrosion behavior of coated Cu substrates in 0.6 M NaCl solution was evaluated via electrochemical impedance spectroscopy, potentiodynamic polarization. Pin-on-disk wear test of coated Cu substrate showed the influence of the pyrolysis temperature on the wear resistance performance of the HC coatings. According to the obtained results, it could be concluded that the HC coatings synthesized at 1100 °C revealed an enhanced comprehensive performance, revealing their possible utilization as a protective coating for Cu substrates in chloride environment. Monte Carlo simulations have been utilized to elucidate the interaction between the Cu surface and HC coatings.

  4. Effect of ion implantation on thin hard coatings

    International Nuclear Information System (INIS)

    Auner, G.; Hsieh, Y.F.; Padmanabhan, K.R.; Chevallier, J.; Soerensen, G.

    1983-01-01

    The surface mechanical properties of thin hard coatings of carbides, nitrides and borides deposited by r.f. sputtering were improved after deposition by ion implantation. The thickness and the stoichiometry of the films were measured by Rutherford backscattering spectrometry and nuclear reaction analysis before and after ion bombardment. The post ion bombardment was achieved with heavy inert ions such as Kr + and Xe + with an energy sufficient to penetrate the film and to reach the substrate. Both the film adhesion and the microhardness were consistently improved. In order to achieve a more detailed understanding, Rb + and Ni + ions were also used as projectiles, and it was found that these ions were more effective than the inert gas ions. (Auth.)

  5. Co-electrodeposition of hard Ni-W/diamond nanocomposite coatings

    Science.gov (United States)

    Zhang, Xinyu; Qin, Jiaqian; Das, Malay Kumar; Hao, Ruru; Zhong, Hua; Thueploy, Adisak; Limpanart, Sarintorn; Boonyongmaneerat, Yuttanant; Ma, Mingzhen; Liu, Riping

    2016-02-01

    Electroplated hard chrome coating is widely used as a wear resistant coating to prolong the life of mechanical components. However, the electroplating process generates hexavalent chromium ion which is known carcinogen. Hence, there is a major effort throughout the electroplating industry to replace hard chrome coating. Composite coating has been identified as suitable materials for replacement of hard chrome coating, while deposition coating prepared using traditional co-deposition techniques have relatively low particles content, but the content of particles incorporated into a coating may fundamentally affect its properties. In the present work, Ni-W/diamond composite coatings were prepared by sediment co-electrodeposition from Ni-W plating bath, containing suspended diamond particles. This study indicates that higher diamond contents could be successfully co-deposited and uniformly distributed in the Ni-W alloy matrix. The maximum hardness of Ni-W/diamond composite coatings is found to be 2249 ± 23 Hv due to the highest diamond content of 64 wt.%. The hardness could be further enhanced up to 2647 ± 25 Hv with heat treatment at 873 K for 1 h in Ar gas, which is comparable to hard chrome coatings. Moreover, the addition of diamond particles could significantly enhance the wear resistance of the coatings.

  6. Application of Hard Coatings for Improved Tribological Performance of Blanking and Piercing Tools

    DEFF Research Database (Denmark)

    Podgornik, B.; Zajec, B.; Bay, Niels

    2010-01-01

    The aim of the present investigation was to examine the possibility of reducing lubrication and replacing expensive tungsten carbide material in blanking/piercing through introduction of hard tool coatings. Results show that hard PVD coatings can be successfully used in blanking/piercing applicat...

  7. Hard coatings by plasma CVD on polycarbonate for automotive and optical applications

    International Nuclear Information System (INIS)

    Schmauder, T.; Nauenburg, K.-D.; Kruse, K.; Ickes, G.

    2006-01-01

    In many applications, plastic surfaces need coatings as a protection against abrasion or weathering. Leybold Optics is developing Plasma CVD processes and machinery for transparent hard coatings (THC) for polycarbonate parts. In this paper we present the current features and remaining challenges of this technique. The coatings generally show excellent adhesion. Abrasion resistance is superior to commonly used lacquers. Climate durability of the coating has been improved to pass the tests demanded by automotive specifications. Current activities are focused on improving the durability under exposure to UV radiation. Estimations show that our high-rate plasma CVD hard coating process is also economically competitive to lacquering

  8. Investigation on hard coating of pivot-jewel bearing and wearing performance

    International Nuclear Information System (INIS)

    Han Kun; Dai Xingjian

    2014-01-01

    The reliability of high speed rotating machine is related to the anti-wear properties of pivot jewel bearing used in the system. To reduce its wearing process, hard coating method is used on the steel pivot. Through the wearing test on specialized facilities, its founded that the TiN coating shows better performance than DLC coating, and multi-layer TiN coating can slow down the pivot's wearing process obviously compared to other methods. (authors)

  9. Life assessment of PVD based hard coatings by linear sweep voltammetry for high performance industrial application

    International Nuclear Information System (INIS)

    Malik, M.; Alam, S.; Irfan, M.; Hassan, Z.

    2006-01-01

    PVD based hard coatings have remarkable achievements in order to improve Tribological and surface properties of coating tools and dies. As PVD based hard coatings have a wide range of industrial applications especially in aerospace and automobile parts where they met different chemical attacks and in order to improve industrial performance these coatings must provide an excellent resistance against corrosion, high temperature oxidation and chemical reaction. This paper focuses on study of behaviour of PVD based hard coatings under different corrosive environments like as H/sub 2/SO/sub 4/, HCl, NaCl, KCl, NaOH etc. Corrosion rate was calculate under linear sweep voltammetry method where the Tafel extrapolation curves used for continuously monitoring the corrosion rate. The results show that these coatings have an excellent resistance against chemical attack. (author)

  10. Al–Mn coating electrodeposited from ionic liquid on NdFeB magnet with high hardness and corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Jingjing; Xu, Bajin; Ling, Guoping, E-mail: linggp@zju.edu.cn

    2014-06-01

    Al–Mn coatings were electrodeposited on sintered NdFeB permanent magnet in MnCl{sub 2}–AlCl{sub 3}–1-ethyl-3-methylim-idazolium chloride (MnCl{sub 2}–AlCl{sub 3}–EMIC) ionic liquid at room temperature. The coatings were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The adhesion strength of the coating on NdFeB substrate was evaluated by thermal shock and scratch test. The hardness and corrosion behavior of Al–Mn coating were measured by a Knoop microhardness tester, immersion test and neutral salt spray test respectively. The results showed that the amorphous structure of the deposits was obtained at the current density of 6 mA/cm{sup 2}, while higher current densities resulted in a mixed structure of amorphous and crystalline. The Al–Mn coating showed excellent adhesion strength on NdFeB substrate with the thermal shock test over 30 cycles and L{sub c} > 80 N. The hardness of Al–Mn coating was up to 5.4 GPa. The amorphous Al–Mn coating showed an anodic sacrificial protection with a low corrosion rate for NdFeB. Meanwhile, the magnetic properties measured by an AMT-4 magnetic measurement device showed that Al–Mn coating did not deteriorate the magnetic property of NdFeB.

  11. Al–Mn coating electrodeposited from ionic liquid on NdFeB magnet with high hardness and corrosion resistance

    International Nuclear Information System (INIS)

    Ding, Jingjing; Xu, Bajin; Ling, Guoping

    2014-01-01

    Al–Mn coatings were electrodeposited on sintered NdFeB permanent magnet in MnCl 2 –AlCl 3 –1-ethyl-3-methylim-idazolium chloride (MnCl 2 –AlCl 3 –EMIC) ionic liquid at room temperature. The coatings were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The adhesion strength of the coating on NdFeB substrate was evaluated by thermal shock and scratch test. The hardness and corrosion behavior of Al–Mn coating were measured by a Knoop microhardness tester, immersion test and neutral salt spray test respectively. The results showed that the amorphous structure of the deposits was obtained at the current density of 6 mA/cm 2 , while higher current densities resulted in a mixed structure of amorphous and crystalline. The Al–Mn coating showed excellent adhesion strength on NdFeB substrate with the thermal shock test over 30 cycles and L c > 80 N. The hardness of Al–Mn coating was up to 5.4 GPa. The amorphous Al–Mn coating showed an anodic sacrificial protection with a low corrosion rate for NdFeB. Meanwhile, the magnetic properties measured by an AMT-4 magnetic measurement device showed that Al–Mn coating did not deteriorate the magnetic property of NdFeB.

  12. The structure and formation of functional hard coatings: a short review

    Directory of Open Access Journals (Sweden)

    Diciuc Vlad

    2017-01-01

    Full Text Available Turning tools come in different shapes and sizes, geometry, base material and coating, according to their destination. They are widely used both for obtaining parts and for machinability tests. In this paper a short review about high-speed steel (HSS turning tools and their coatings is presented. Hard coatings formed on the tool material should be functional depending on the tool final application. Requirements for hard coatings and technological problems for layer formation on the real cutting tool are discussed.

  13. CrN-based wear resistant hard coatings for machining and forming tools

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S; Cooke, K E; Teer, D G [Teer Coatings Ltd, West Stone House, Berry Hill Industrial Estate, Droitwich, Worcestershire WR9 9AS (United Kingdom); Li, X [School of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT (United Kingdom); McIntosh, F [Rolls-Royce plc, Inchinnan, Renfrewshire PA4 9AF, Scotland (United Kingdom)

    2009-05-21

    Highly wear resistant multicomponent or multilayer hard coatings, based on CrN but incorporating other metals, have been developed using closed field unbalanced magnetron sputter ion plating technology. They are exploited in coated machining and forming tools cutting and forming of a wide range of materials in various application environments. These coatings are characterized by desirable properties including good adhesion, high hardness, high toughness, high wear resistance, high thermal stability and high machining capability for steel. The coatings appear to show almost universal working characteristics under operating conditions of low and high temperature, low and high machining speed, machining of ordinary materials and difficult to machine materials, and machining under lubricated and under minimum lubricant quantity or even dry conditions. These coatings can be used for cutting and for forming tools, for conventional (macro-) machining tools as well as for micromachining tools, either as a single coating or in combination with an advanced, self-lubricating topcoat.

  14. A comparative tribological study of chromium coatings with different specific hardness

    International Nuclear Information System (INIS)

    Darbeida, A.; Von Stebut, J.; Barthole, M.; Belliard, P.; Lelait, L.

    1995-06-01

    The wear resistance in dry friction of two electrolytic and two pVD hard chromium coatings deposited on construction steel substrates is studied by means of standard pin on disc multi-pass, unidirectional operation. For both of these friction modes low cycle high load operation with cemented carbide pins leads to essentially coatings hardness controlled, abrasive wear. For these well adhering commercial coatings (both for through thickness cracking and for spalling failure) assessed by standard testing, are inadequate for quality ranking with respect to wear resistance. Steady state friction corresponds to a stabilised third body essentially composed of chromium oxide. (authors). 13 refs., 7 figs., 1 tab

  15. Investigation of sputtered Mo2BC hard coatings : correlation of nanostructure and mechanical properties

    OpenAIRE

    Gleich, Stephan

    2017-01-01

    This thesis is dedicated to the study of Mo2BC coatings on silicon substrates. According to reported ab initio calculations in literature, which predicted a high stiffness and a moderate ductile behavior for the material, Mo2BC is a predestinated candidate to act as hard coating layer. The focus in this thesis is set on the nanostructure of Mo2BC hard coatings explored by transmission electron microscopy as a function of the used substrate temperature, applied during the deposition process us...

  16. Investigation of the Influence of Ni Doping on the Structure and Hardness of Ti-Ni-C Coatings

    Directory of Open Access Journals (Sweden)

    J. Daniel

    2017-01-01

    Full Text Available Nanocomposite nc-TiC/a-C:H thin films exhibit unique combination of mechanical properties, high hardness, low friction, and wear. Selective doping by weak-carbide forming element can be used in order to specifically design the physical and chemical properties of nc-TiC/a-C:H coatings. In this paper we report on an effect of nickel addition on structure and hardness of the nc-TiC/a-C:H coatings. The effect of Ni alloying on the coating structure under conditions of DCMS and HiPIMS depositions was studied. The coating structure was correlated with the coating hardness. The grain size, the grain carbon vacancy concentration, and the mean grain separation were found to be the key parameters determining the coating hardness. Ni doping proved to have a significant effect on the coating microstructure which resulted in changes of the hardness of the deposited coatings.

  17. Hard, infrared black coating with very low outgassing

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmenko, P J; Behne, D M; Casserly, T; Boardman, W; Upadhyaya, D; Boinapally, K; Gupta, M; Cao, Y

    2008-06-02

    Infrared astronomical instruments require absorptive coatings on internal surfaces to trap scattered and stray photons. This is typically accomplished with any one of a number of black paints. Although inexpensive and simple to apply, paint has several disadvantages. Painted surfaces can be fragile, prone to shedding particles, and difficult to clean. Most importantly, the vacuum performance is poor. Recently a plasma enhanced chemical vapor deposition (PECVD) process was developed to apply thick (30 {micro}m) diamond-like carbon (DLC) based protective coatings to the interior of oil pipelines. These DLC coatings show much promise as an infrared black for an ultra high vacuum environment. The coatings are very robust with excellent cryogenic adhesion. Their total infrared reflectivity of < 10% at normal incidence approaches that of black paints. We measured outgas rates of <10{sup -12} Torr liter/sec cm{sup 2}, comparable to bare stainless steel.

  18. Radiation Hard Multi-Layer Optical Coatings, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Next generation space telescopes require advanced optical coatings to provide low loss transmission of light in a variety of spectral ranges and protect optical...

  19. A study of the nanostructure and hardness of electron beam evaporated TiAlBN Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Baker, M.A., E-mail: m.baker@surrey.ac.u [The Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH (United Kingdom); Monclus, M.A. [National Physical Laboratory, Hampton Road, Teddington, TW11 0LW (United Kingdom); Rebholz, C. [Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia (Cyprus); Gibson, P.N. [Institute for Health and Consumer Protection, Joint Research Centre, I-21027 Ispra (Italy); Leyland, A.; Matthews, A. [Department of Engineering Materials, University of Sheffield, Sheffield S1 3JD (United Kingdom)

    2010-05-31

    TiAlBN coatings have been deposited by electron beam (EB) evaporation from a single TiAlBN material source onto AISI 316 stainless steel substrates at a temperature of 450 {sup o}C and substrate bias of - 100 V. The stoichiometry and nanostructure have been studied by X-ray photoelectron spectroscopy, X-ray diffraction and transmission electron microscopy. The hardness and elastic modulus were determined by nanoindentation. Five coatings have been deposited, three from hot-pressed TiAlBN material and two from hot isostatically pressed (HIPped) material. The coatings deposited from the hot-pressed material exhibited a nanocomposite nc-(Ti,Al)N/a-BN/a-(Ti,Al)B{sub 2} structure, the relative phase fraction being consistent with that predicted by the equilibrium Ti-B-N phase diagram. Nanoindentation hardness values were in the range of 22 to 32 GPa. Using the HIPped material, coating (Ti,Al)B{sub 0.29}N{sub 0.46} was found to have a phase composition of 72-79 mol.% nc-(Ti,Al)(N,B){sub 1-x}+ 21-28 mol.% amorphous titanium boride and a hardness of 32 GPa. The second coating, (Ti,Al)B{sub 0.66}N{sub 0.25}, was X-ray amorphous with a nitride+boride multiphase composition and a hardness of 26 GPa. The nanostructure and structure-property relationships of all coatings are discussed in detail. Comparisons are made between the single-EB coatings deposited in this work and previously deposited twin-EB coatings. Twin-EB deposition gives rise to lower adatom mobilities, leading to (111) (Ti,Al)N preferential orientation, smaller grain sizes, less dense coatings and lower hardnesses.

  20. Evaluation of End Mill Coatings

    Energy Technology Data Exchange (ETDEWEB)

    L. J. Lazarus; R. L. Hester,

    2005-08-01

    Milling tests were run on families of High Speed Steel (HSS) end mills to determine their lives while machining 304 Stainless Steel. The end mills tested were made from M7, M42 and T15-CPM High Speed Steels. The end mills were also evaluated with no coatings as well as with Titanium Nitride (TiN) and Titanium Carbo-Nitride (TiCN) coatings to determine which combination of HSS and coating provided the highest increase in end mill life while increasing the cost of the tool the least. We found end mill made from M42 gave us the largest increase in tool life with the least increase in cost. The results of this study will be used by Cutting Tool Engineering in determining which end mill descriptions will be dropped from our tool catalog.

  1. Plasma spraying of hard magnetic coatings based on Sm-Co alloys

    International Nuclear Information System (INIS)

    KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" data-affiliation=" (Siberian State Aerospace University named after Academician M.F. Reshetnev 31 KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" >Saunin, V N; KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" data-affiliation=" (Siberian State Aerospace University named after Academician M.F. Reshetnev 31 KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" >Telegin, S V

    2015-01-01

    Our research is focused on the formation of hard magnetic coatings by plasma spraying an arc-melted Sm-Co powder. We have studied basic magnetic characteristics depending on the components ratio in the alloy. A sample with a 40 wt.% Sm coating exhibits the highest coercive force (63 kOe) as compared to near-to-zero coercive force in the starting powder. X-ray structure analysis of the starting alloy and the coating reveals that the amount of SmCo 5 phase in the sprayed coating increases occupying up to 2/3 of the sample. We have also studied temperature dependence of the coating and have been able to obtain plasma sprayed permanent magnets operating within the temperature range from -100 to +500 °C. The technique used does not involve any additional thermal treatment and allows a coating to be formed right on the magnetic conductor surface irrespective of the conductor geometry

  2. Electroformed Nanocrystalline Coatings: An Advanced Alternative to Hard Chrome Electroplating

    Science.gov (United States)

    2003-11-21

    100mL/min. The vials were then analyzed for any traces of cobalt, iron, chloride, sulphate, and for two additives. A summary of the emission results...observed that correspond to cobalt- phosphites , indicating that the phosphorus is present in the deposits in a solid solution state (similar to XRD...precipitation of cobalt- phosphites from the supersaturated solid solution at elevated temperatures. Figure 4-2 shows the variation in hardness as a

  3. Gloss evaluation from soft and hard metrologies.

    Science.gov (United States)

    Wang, Zihao; Xu, Lihao; Hu, Yu; Mirjalili, Fereshteh; Luo, Ming Ronnier

    2017-09-01

    Recent advances in bidirectional reflectance distribution function (BRDF) acquisitions have provided a novel approach for appearance measurement and analysis. In particular, since gloss appearance is dependent on the directional reflective properties of surfaces, it is reasonable to leverage the BRDF for gloss evaluation. In this paper, we investigate gloss appearance from both soft metrology and hard metrology. A psychophysical experiment was conducted for the gloss assessment of 47 neutral-color samples. In the evaluation of gloss perception from gloss meter measurements, we report several ambiguous correspondences in the medium gloss range. In order to analyze and explain this phenomenon, the BRDF was acquired and examined using a commercial BRDF measuring device. With an improved correlation-to-visual perception, we propose a two-dimensional gloss model by combining a parameter, the standard deviation of the specular lobe, from Ward's BRDF model with measured gloss values.

  4. Development and characterization of nano structured hard coatings for high performance tools by using PVD technique

    International Nuclear Information System (INIS)

    Irfan, M.; Alam, S.; Hassan, Z.; Iftikhar, F.; Khadim, S.

    2006-01-01

    No doubt hard coatings nave major applications in high performance cutting tools in order to improve tribological and mechanical properties of these tools since last years. The actual top development in this regard is the development of PVD based AlTiN coatings and their supplementation with nano. layers. In present these nano coatings are replaced by nano composites along with an additional development of Multilayer Nano structured coatings. This PVD based nano structured coating development optimized by process parameters, crystalline structure and deposition in multilayer. These coating are definitely produced by combination of ARC and Sputtering with filtration of arc droplets. It is studied that the properties like oxidation resistance, wear resistance and resistance against chemical reaction may be obtained by alloying additions of different elements. This paper presents different development stages and Process parameters for- producing high performance Nanostructure coatings and including adhesion test by using Kalomax system for determination of adhesion strength of these coatings and coating thickness measurements by using image analyzer system. Results and conclusions are showing the optimum values for better coatings for different applications. (author)

  5. Tribological performance of hard carbon coatings on 440C bearing steel

    Energy Technology Data Exchange (ETDEWEB)

    Kustas, F M; Misra, M S; Shepard, D F; Froechtenigt, J F [Martin Marietta Astronautics Group, Denver, CO (United States)

    1991-11-01

    Hard carbon coatings such as amorphous carbon, diamond and diamond-like carbon have received considerable attention for tribological applications owing to their high hardness, high modulus and desirable surface properties. Unfortunately, most of the deposition techniques induce high substrate temperatures that would temper traditional bearing steels and reduce the substrate load-carrying capability. Therefore, to effectively use these desirable coatings, a lower temperature deposition technique is required. Ion beam deposition can provide essentially ambient temperature conditions, accurate control of process parameters and good coating-substrate adhesion. To use these attributes, a test program was initiated to deposit mass-analyzed, high purity C{sup +} and CH{sub 4}{sup +} ions on molybdenum and 440C bearing steel for subsequent characterization by Raman spectroscopy and friction-wear tests. Results for a coating deposited from a carbon monoxide source showed an amorphous carbon-microcrystalline graphtie structure which exhibited very high microhardness and a three fold reduction in coefficient of friction for unlubricated tests compared to untreated 440C steel. In addition, incrementally increasing the applied load (by up to a factor of 5) resulted in progressively lower coefficients of friction, which conforms to solid lubrication theory. End-of-travel wear debris and some limited coating delamination were observed within thinner areas of the coating. Therefore an amorphous carbon-graphite coating applied to 440C steel at ambient temperature exhibits solid lubricating film characteristics with high load-carrying capability. (orig.).

  6. Depth-resolved X-ray residual stress analysis in PVD (Ti, Cr) N hard coatings

    CERN Document Server

    Genzel, C

    2003-01-01

    Physical vapour deposition (PVD) of thin hard coatings on TiN basis is usually performed at rather low temperatures (T sub D < 500 C) far from thermal equilibrium, which leads to high intrinsic residual stresses in the growing film. In contrast to the extrinsic thermal residual stresses which can easily be estimated from the difference of the coefficients of thermal expansion between the substrate and the coating, a theoretical prediction of the intrinsic residual stresses is difficult, because their amount as well as their distribution within the film depend in a very complex way on the deposition kinetics. By the example of strongly fibre-textured PVD (Ti, Cr)N coatings which have been prepared under defined variation of the deposition parameters in order to adjust the residual stress distribution within the coatings, the paper compares different X-ray diffraction techniques with respect to their applicability for detecting residual stresses which are non-uniform over the coating thickness. (orig.)

  7. Multilayer coating facility for the HEFT hard x-ray telescope

    DEFF Research Database (Denmark)

    Cooper-Jensen, Carsten P.; Christensen, Finn Erland; Chen, Hubert

    2001-01-01

    A planar magnetron sputtering facility has been established at the Danish Space Research Institute (DSRI) for the production coating of depth graded multilayers on the thermally slumped glass segments which form the basis for the hard X-ray telescope on the HEFT balloon project. The facility...

  8. Highly hard yet toughened bcc-W coating by doping unexpectedly low B content

    KAUST Repository

    Yang, Lina; Zhang, Kan; Wen, Mao; Hou, Zhipeng; Gong, Chen; Liu, Xucheng; Hu, Chaoquan; Cui, Xiaoqiang; Zheng, Weitao

    2017-01-01

    of improved hardness (2 × larger than pure W) and superior toughness (higher crack formation threshold compared to pure W). We believe this is an innovative sight to design new generation of transition-metal-based multifunctional coatings. Besides, our results

  9. Functional Coatings or Films for Hard-Tissue Applications

    Directory of Open Access Journals (Sweden)

    Guocheng Wang

    2010-07-01

    Full Text Available Metallic biomaterials like stainless steel, Co-based alloy, Ti and its alloys are widely used as artificial hip joints, bone plates and dental implants due to their excellent mechanical properties and endurance. However, there are some surface-originated problems associated with the metallic implants: corrosion and wear in biological environments resulting in ions release and formation of wear debris; poor implant fixation resulting from lack of osteoconductivity and osteoinductivity; implant-associated infections due to the bacterial adhesion and colonization at the implantation site. For overcoming these surface-originated problems, a variety of surface modification techniques have been used on metallic implants, including chemical treatments, physical methods and biological methods. This review surveys coatings that serve to provide properties of anti-corrosion and anti-wear, biocompatibility and bioactivity, and antibacterial activity.

  10. INFLUENCE OF THE THICKNESS OF Ni-P COATING APPLIED ON 7075 ALUMINUM ALLOY ON ITS HARDNESS

    Directory of Open Access Journals (Sweden)

    Kazimierz Czapczyk

    2016-12-01

    Full Text Available The paper presents the results of hardness tests of aluminum alloy AW-7075 (for plastic processing and Ni-P chemical coatings (nickel-phosphorus which had been applied by the no-current method. Coatings of various thickness have been made and their influence on the increase of the top layer hardness has been determined, as well as the increase of the hardness of the coating and substrate system after puncturing the coating with an indenter. The purpose of the investigation was to determine the possibility of applying the Ni-P coating for selected technical applications, among others, by the selection of its optimum thickness on the hard aluminum alloy and by the determination of the deformation resistance of the top layer if the given coating.

  11. Surface Morphology and Hardness Analysis of TiCN Coated AA7075 Aluminium Alloy

    Science.gov (United States)

    Srinath, M. K.; Ganesha Prasad, M. S.

    2017-12-01

    Successful titanium carbonitride (TiCN) coating on AA7075 plates using the PVD technique depends upon many variables, including temperature, pressure, incident angle and energy of the reactive ions. Coated specimens have shown an increase in their surface hardness of 2.566 GPa. In this work, an attempt to further augment the surface hardness and understand its effects on the surface morphology was performed through heat treatments at 500°C for different duration of times. Specimen's heat treated at 500°C for 1 h exhibited a maximum surface hardness of 6.433 GPa, corresponding to an increase of 92.07%. The XRD results showed the presence of Al2Ti and AlTi3N and indicate the bond created between them. Unit cell lattice parameters in the XRD data are calculated using Bragg's law. The SEM images exhibit increasing crack sizes as the heat treatment time is increased. From the studies, the heat treatment duration can be optimized to 1 h, which exhibited an augmented surface hardness, as further increases in durations caused a drop in the surface hardness. The heat treatment effectively modified the surface hardness. Equations providing the relationships that temperature and time have with the reaction parameters are presented.

  12. Characterization of Pulse Reverses Electroforming on Hard Gold Coating.

    Science.gov (United States)

    Byoun, Young-Min; Noh, Young-Tai; Kim, Young-Geun; Ma, Seung-Hwan; Kim, Gwan-Hoon

    2018-03-01

    Effect of pulse reverse current (PRC) method on brass coatings electroplated from gold solution was investigated by various plating parameters such as plating duration, the anodic duty cycle, the anodic current density and the cathodic current density. The reversed current results in a significant change in the morphology of electrodeposits, improvement of the overall current efficiency and reduction of deposit porosity. With longer pulses, hemispherical surface features are generated, while larger grains result from shorter pulse widths. The porosity of the plated samples is found to decrease compared with results at the same time-average plating rate obtained from DC or Pulse plating. A major impediment to reducing gold later thickness is the corrosion of the underlying substrate, which is affected by the porosity of the gold layer. Both the morphology and the hydrogen evolution reaction have significant impact on porosity. PRC plating affect hydrogen gold and may oxidize hydrogen produced during the cathodic portion of the waveform. Whether the dissolution of gold and oxidation of hydrogen occur depends on the type of plating bath and the plating conditions adapted. In reversed pulse plating, the amount of excess near-surface cyanide is changed after the cathodic current is applied, and the oxidation of gold under these conditions has not been fully addressed. The effects of the current density, pulse-reverse ratio and brightener concentration of the electroplating process were investigated and optimized for suitable performance.

  13. Coating of Ultra-Small Micro End Mills: Analysis of Performance and Suitability of Eight Different Hard-Coatings

    Directory of Open Access Journals (Sweden)

    Martin Bohley

    2018-03-01

    Full Text Available Due to the constant need for better functionalized surfaces or smaller, function integrated components, precise and efficient manufacturing processes have to be established. Micro milling with micro end mills is one of the most promising processes for this task as it combines a high geometric flexibility in a wide range of machinable materials with low set-up costs. A downside of this process is the wear of the micro end mills. Due to size effects and the relatively low cutting speed, the cutting edge is especially subjected to massive abrasive wear. One possibility to minimize this wear is coating of micro end mills. This research paper describes the performance of eight different hard coatings for micro end mills with a diameter <40 µm and discusses some properties for the best performing coating type. With this research, it is therefore possible to boost the possibilities of micro milling for the manufacture of next generation products.

  14. Microstructures, hardness and bioactivity of hydroxyapatite coatings deposited by direct laser melting process

    International Nuclear Information System (INIS)

    Tlotleng, Monnamme; Akinlabi, Esther; Shukla, Mukul; Pityana, Sisa

    2014-01-01

    Hydroxyapatite (HAP) coatings on bioinert metals such as Ti–6Al–4V are necessary for biomedical applications. Together, HAP and Ti–6Al–4V are biocompatible and bioactive. The challenges of depositing HAP on Ti–6Al–4V with traditional thermal spraying techniques are well founded. In this paper, HAP was coated on Ti–6Al–4V using direct laser melting (DLM) process. This process, unlike the traditional coating processes, is able to achieve coatings with good metallurgical bonding and little dilution. The microstructural and mechanical properties, chemical composition and bio-activities of the produced coatings were studied with optical microscopy, scanning electron microscope equipped with energy dispersive X-ray spectroscopy, and Vickers hardness machine, and by immersion test in Hanks' solution. The results showed that the choice of the laser power has much influence on the evolving microstructure, the mechanical properties and the retainment of HAP on the surface of the coating. Also, the choice of laser power of 750 W led to no dilution. The microhardness results inferred a strong intermetallic–ceramic interfacial bonding; which meant that the 750 W coating could survive long in service. Also, the coating was softer at the surface and stronger in the heat affected zones. Hence, this process parameter setting can be considered as an optimal setting. The soak tests revealed that the surface of the coating had unmelted crystals of HAP. The CaP ratio conducted on the soaked coating was 2.00 which corresponded to tetra calcium phosphate. This coating seems attractive for metallic implant applications. - Highlights: • Characteristics of HAP coatings produced on Ti-6Al-4V achieved with direct laser melting are reported. • Optimal process parameters necessary to achieve biocompatible coating are reported. • The SEM micrograph of the soaked HAP coating revealed partially melted crystals of HAP. • The HAP coating was retained at the surface of

  15. Microstructures, hardness and bioactivity of hydroxyapatite coatings deposited by direct laser melting process

    Energy Technology Data Exchange (ETDEWEB)

    Tlotleng, Monnamme, E-mail: MTlotleng@csir.co.za [Laser Materials Processing Group, National Laser Center CSIR, Pretoria 0001 (South Africa); Department of Mechanical Engineering Science, University of Johannesburg, Auckland Park, Kingsway Campus, Johannesburg 2006 (South Africa); Akinlabi, Esther [Department of Mechanical Engineering Science, University of Johannesburg, Auckland Park, Kingsway Campus, Johannesburg 2006 (South Africa); Shukla, Mukul [Department of Mechanical Engineering Technology, University of Johannesburg, Doornfontein Campus, Johannesburg 2006 (South Africa); Department of Mechanical Engineering, MNNIT, Allahabad, UP 211004 (India); Pityana, Sisa [Laser Materials Processing Group, National Laser Center CSIR, Pretoria 0001 (South Africa); Department of Chemical and Metallurgical Engineering, Tshwane University of Technology, Pretoria 0001 (South Africa)

    2014-10-01

    Hydroxyapatite (HAP) coatings on bioinert metals such as Ti–6Al–4V are necessary for biomedical applications. Together, HAP and Ti–6Al–4V are biocompatible and bioactive. The challenges of depositing HAP on Ti–6Al–4V with traditional thermal spraying techniques are well founded. In this paper, HAP was coated on Ti–6Al–4V using direct laser melting (DLM) process. This process, unlike the traditional coating processes, is able to achieve coatings with good metallurgical bonding and little dilution. The microstructural and mechanical properties, chemical composition and bio-activities of the produced coatings were studied with optical microscopy, scanning electron microscope equipped with energy dispersive X-ray spectroscopy, and Vickers hardness machine, and by immersion test in Hanks' solution. The results showed that the choice of the laser power has much influence on the evolving microstructure, the mechanical properties and the retainment of HAP on the surface of the coating. Also, the choice of laser power of 750 W led to no dilution. The microhardness results inferred a strong intermetallic–ceramic interfacial bonding; which meant that the 750 W coating could survive long in service. Also, the coating was softer at the surface and stronger in the heat affected zones. Hence, this process parameter setting can be considered as an optimal setting. The soak tests revealed that the surface of the coating had unmelted crystals of HAP. The CaP ratio conducted on the soaked coating was 2.00 which corresponded to tetra calcium phosphate. This coating seems attractive for metallic implant applications. - Highlights: • Characteristics of HAP coatings produced on Ti-6Al-4V achieved with direct laser melting are reported. • Optimal process parameters necessary to achieve biocompatible coating are reported. • The SEM micrograph of the soaked HAP coating revealed partially melted crystals of HAP. • The HAP coating was retained at the surface of

  16. Correlation between hardness and water absorption properties of Saudi kaolin and white clay geopolymer coating

    Science.gov (United States)

    Ramasamy, Shamala; Abdullah, Mohd Mustafa Al Bakri; Huang, Yue; Hussin, Kamarudin; Wang, Jin; Shahedan, Noor Fifinatasha

    2017-09-01

    Geopolymer is an uprising technology that is being studied worldwide. Geopolymer raw materials are basically aluminosilicate source materials. However, this technology is yet to infiltrate into pipelines and coating industries which initiated our research idea. The idea of creating universal geopolymer based coating material is mainly to help oil and gas industry reduce its maintenance cost. Kaolin based geopolymer paste was coated on glass reinforced epoxy (GRE) substrates which are majorly used as pipeline material in the oil and gas industry at Saudi Arabia. Kaolin and white clay was chosen as raw material to study the possibilities of utilizing underused aluminosilicate raw materials for geopolymer coating. To obtain suitable formulation, Na2SiO3/NaOH ratio was varied from 0.40 untill 0.60 while other parameters such as solid/liquid ratio and NaOH molarity were kept constant at values as per previous works. Geopolymer coated GRE substrates were then subjected to water absorption, flexural strength and hardness test to validate our findings. Water absorption is a crucial test as for coating materials which justifies the pratical usability of the coating product. Upon testing, kaolin and white clay based geopolymer coating each shows promising properties at Na2SiO3/NaOH ratio of 0.45 and 0.50 each.

  17. Establishment of Wear Resistant HVOF Coatings for 50CrMo4 Chromium Molybdenum Alloy Steel as an Alternative for Hard Chrome Plating

    Science.gov (United States)

    Karuppasamy, S.; Sivan, V.; Natarajan, S.; Kumaresh Babu, S. P.; Duraiselvam, M.; Dhanuskodi, R.

    2018-05-01

    High cost imported components of seamless steel tube manufacturing plants wear frequently and need replacement to ensure the quality of the product. Hard chrome plating, which is time consuming and hazardous, is conventionally used to restore the original dimension of the worn-out surface of the machine components. High Velocity Oxy-Fuel (HVOF) thermal spray coatings with NiCrBSi super alloy powder and Cr3C2 NiCr75/25 alloy powder applied on a 50CrMo4 (DIN-1.7228) chromium molybdenum alloy steel, the material of the wear prone machine component, were evaluated for use as an alternative for hard chrome plating in this present work. The coating characteristics are evaluated using abrasive wear test, sliding wear test and microscopic analysis, hardness test, etc. The study results revealed that the HVOF based NiCrBSi and Cr3C2NiCr75/25 coatings have hardness in the range of 800-900 HV0.3, sliding wear rate in the range of 50-60 µm and surface finish around 5 microns. Cr3C2 NiCr75/25 coating is observed to be a better option out of the two coatings evaluated for the selected application.

  18. Evaluation of irradiated coating material specimens

    International Nuclear Information System (INIS)

    Lee, Yong Jin; Nam, Seok Woo; Cho, Lee Moon

    2007-12-01

    Evaluation result of irradiated coating material specimens - Coating material specimens radiated Gamma Energy(Co 60) in air condition. - Evaluation conditions was above 1 X 10 4 Gy/hr, and radiated TID 2.0 X 10 6 Gy. - The radiated coating material specimens, No Checking, Cracking, Flaking, Delamination, Peeling and Blistering. - Coating system at the Kori no. 1 and APR 1400 Nuclear power plant, evaluation of irradiated coating materials is in accordance with owner's requirement(2.0 X 10 6 Gy)

  19. Development of a hard nano-structured multi-component ceramic coating by laser cladding

    International Nuclear Information System (INIS)

    Masanta, Manoj; Ganesh, P.; Kaul, Rakesh; Nath, A.K.; Roy Choudhury, A.

    2009-01-01

    The present paper reports laser-assisted synthesis of a multi-component ceramic composite coating consisting of aluminum oxide, titanium di-boride and titanium carbide (Al 2 O 3 -TiB 2 -TiC). A pre-placed powder mixture of aluminum (Al), titanium oxide (TiO 2 ) and boron carbide (B 4 C) was made to undergo self-propagating high-temperature synthesis (SHS) by laser triggering. Laser subsequently effected cladding of the products of SHS on the substrate. The effect of laser scanning speed on the hardness, microstructure and phase composition of the composite coating was investigated. The coating exhibited an increase in hardness and a decrease in grain size with increase in laser scanning speed. A maximum micro-hardness of 2500 HV 0.025 was obtained. X-ray diffraction (XRD) of the top surface of the coating revealed the presence of aluminum oxide (Al 2 O 3 ), titanium di-boride (TiB 2 ) and titanium carbide (TiC) along with some non-stoichiometric products of the Ti-Al-B-C-O system. Field emission gun scanning electron microscopy (FESEM) and high-resolution transmission electron microscopic (HRTEM) analysis revealed some nano-structured TiB 2 and Al 2 O 3 , which are discussed in detail.

  20. Development of a hard nano-structured multi-component ceramic coating by laser cladding

    Energy Technology Data Exchange (ETDEWEB)

    Masanta, Manoj [Department of Mechanical Engineering, IIT Kharagpur, West Bengal 721302 (India); Ganesh, P.; Kaul, Rakesh [Laser Material Processing Division, Raja Ramanna Centre for Advanced Technology, Indore (India); Nath, A.K. [Department of Mechanical Engineering, IIT Kharagpur, West Bengal 721302 (India); Roy Choudhury, A., E-mail: roychoudhuryasimava@gmail.com [Department of Mechanical Engineering, IIT Kharagpur, West Bengal 721302 (India)

    2009-05-20

    The present paper reports laser-assisted synthesis of a multi-component ceramic composite coating consisting of aluminum oxide, titanium di-boride and titanium carbide (Al{sub 2}O{sub 3}-TiB{sub 2}-TiC). A pre-placed powder mixture of aluminum (Al), titanium oxide (TiO{sub 2}) and boron carbide (B{sub 4}C) was made to undergo self-propagating high-temperature synthesis (SHS) by laser triggering. Laser subsequently effected cladding of the products of SHS on the substrate. The effect of laser scanning speed on the hardness, microstructure and phase composition of the composite coating was investigated. The coating exhibited an increase in hardness and a decrease in grain size with increase in laser scanning speed. A maximum micro-hardness of 2500 HV{sub 0.025} was obtained. X-ray diffraction (XRD) of the top surface of the coating revealed the presence of aluminum oxide (Al{sub 2}O{sub 3}), titanium di-boride (TiB{sub 2}) and titanium carbide (TiC) along with some non-stoichiometric products of the Ti-Al-B-C-O system. Field emission gun scanning electron microscopy (FESEM) and high-resolution transmission electron microscopic (HRTEM) analysis revealed some nano-structured TiB{sub 2} and Al{sub 2}O{sub 3}, which are discussed in detail.

  1. Effect of Interlayer Coating Thickness on the Hardness and Adhesion for the Tungsten Carbide Cutting Tool

    Directory of Open Access Journals (Sweden)

    Kamil Jawad Kadhim

    2017-12-01

    Full Text Available The thin film of the (Al,TiN coating is studied with the aid of two parameters: hardness and adhesion.  These parameters are very close to each other; however, in deposition field they could be interpreted differently.  Several coatings of (Al,TiN layers are developed on tungsten carbide insert using the standard commercial Al0.67Ti0.33 cathodes in cathodic arc plating system(PVD. The influence of coating layer thickness on the mechanical properties of the coatings was investigated via two parameters: hardness and adhesion are characterized by the Rockwell tester Vickers tester.  The measurements reveal that the highest hardness appears for the (Al,TiN thickness of 5.815 µm while the highest adhesion appears at a thickness of 3.089 µm.  At the opposite extreme, the lowest hardness appears at 2.717 µm and the lowest hardness at 5.815 µm. Overall, the (Al/Ti N coating of the thickness of 5.815 µm is controversial as it exhibits the highest hardness and the lowest adhesion. This result could be related to the effect of the formation of the micro-particle (MPs which has a direct effect on the hardness because these MPs appear mainly on the surface and their presence at the interface is very limited.  In addition, the creation of Ti buffering layer to reduce the delamination has its major effect on the adhesion but has no effect on the morphology of the surface.  For these two reasons and the effect of the bias voltage, the results presented in this paper might show slight differences with other published papers.  The composition of the (Al,TiN layer is characterized and, seemingly, it shows one important result which is showing that the ultimate composition of the (Al,TiN layer (Ti0.62Al0.38 is very close to the original target used in this study (Al0.67Ti0.33.

  2. The hardness of the hydroxyapatite-titania bilayer coatings by microindentation and nanoindentation testing

    Science.gov (United States)

    SIDANE, Djahida; KHIREDDINE, Hafit; YALA, Sabeha

    2017-12-01

    The aim of this paper is to investigate the effect of the addition of titania (TiO2) inner-layer on the morphological and mechanical properties of hydroxyapatite (HAP) bioceramic coatings deposited on 316L stainless steel (316L SS) by sol-gel method in order to improve the properties of hydroxyapatite and expand its clinical application. The addition of TiO2 as sublayer of a hydroxyapatite coating results in changes in surface morphology as well as an increase of the microhardness. The deposition of the inner-layer provides the formation of new types of hydroxyapatite coatings at the same condition of annealing. This represents an advantage for the various applications of the hydroxyapatite bioceramic in the medical field. Classical hardness measurements conducted on the coated systems under the same indentation load (10g) indicated that the microhardness of the HAP coating is improved by the addition of TiO2 inner-layer on the 316L stainless steel substrate. The hardness values obtained from both classical tests in microindentation and the continuous stiffness measurement mode in nanoindentation are slightly different. This is because nanoindentation is more sensitive to the surface roughness and the influence of defects that could be present into the material. Moreover, nanoindentation is the most useful method to separate the contribution of each layer in the bilayer coatings. In this study, the hardness is comparable with those reported previously for pure HAP ceramics (1.0-5.5 GPa) which are close to the properties of natural teeth.

  3. Ultra-hard ceramic coatings fabricated through microarc oxidation on aluminium alloy

    International Nuclear Information System (INIS)

    Wu Hanhua; Wang Jianbo; Long Beiyu; Long Beihong; Jin Zengsun; Naidan Wang; Yu Fengrong; Bi Dongmei

    2005-01-01

    Ultra-hard ceramic coatings with microhardness of 2535 Hv have been synthesized on the Al alloy substrate by microarc oxidation (MAO) technique. The effects of anodic current density (j a ) and the ratio of cathodic to anodic current density (j c /j a ) on the mechanical and corrosion resistance properties of MAO coatings have been studied by microhardness and pitting corrosion tests, respectively. In addition, the phase composition and microstructure of the coatings were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results show that the coatings prepared at high anodic current density consist mainly of α-Al 2 O 3 , while those fabricated at low anodic current density are almost composed of γ-Al 2 O 3 . Microhardness test shows that the coatings have high microhardness, and the highest one is found in the coating formed at j a = 15 A/dm 2 and j c /j a = 0.7. Pitting corrosion test shows that the structure of coatings is strongly influenced by the varying j c /j a

  4. Ti-Al-Si-C-N hard coatings synthesized by hybrid arc enhanced magnetron sputtering

    International Nuclear Information System (INIS)

    Wu, Guizhi; Liu, Sitao; Ma, Shengli; Xu, Kewei; Vincent, Ji; Chu, Paul K.

    2010-01-01

    Ti-Al-Si-C-N coatings are deposited by hybrid arc-enhanced magnetic sputtering and characterized by various micro- and macro-tools. X-ray diffraction, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy reveal that the coatings are nanocomposites consisting of nanocrystallites and amorphous phases. They are generally in the form of nc-(Ti,Al)(C,N)/a-Si_3N_4/a-C depending on the composition of the coatings. With increasing Al concentrations, the X-ray diffraction peaks shift to a lower angle indicating compressive stress in the coatings. The measured hardness also diminishes implying reduced contributions from the self-organized stable nanostructure. The dry friction coefficients of the Ti-Al-Si-C-N coatings are found to be about 0.3 which is lower than that of conventional Ti-Si-N coatings. These coatings can find potential applications requiring high temperature with heavy contact loading. (author)

  5. Electrodeposition of Nanocrystalline Co-P Coatings as a Hard Chrome Alternative (Briefing Charts)

    Science.gov (United States)

    2011-02-10

    chrome plating utilizes chromium in the hexavalent state (Cr6+) Cr6+ is a known carcinogen and poses a health risk to operators OSHA lowered the Cr6+ PEL...from 52 µg/m3 to 5 µg/m3 8 Apr 09, Memorandum, DoD Directive Hexavalent Chromium Management Policy NAVAIR Cr6+ Authorization Process Hard Chrome ...Aerospace & Defense February 10, 2011 Electrodeposition of Nanocrystalline Co-P Coatings as a Hard Chrome Alternative Jack Benfer Co-PI NAVAIR

  6. Multilayer coatings containing diamond and other hard materials on hardmetal substrates

    International Nuclear Information System (INIS)

    Koepf, A.; Haubner, R.; Lux, B.

    2001-01-01

    In order to improve the wear resistance of hardmetal cutting tools, coatings of hard materials were established. Especially the production of multilayer coatings, which combine useful properties of different materials was a topic of industrial and academic research. The present work examined the possibilities of combining diamond as basic layer with protective CVD layers of TiC, TiN, Ti(C,N) and Al 2 O 3 . All these combinations could be realized and some showed quite good adherence under strain, which offers possibilities for technical applications. (author)

  7. Experimental Study on the Influence on Vibration Characteristics of Thin Cylindrical Shell with Hard Coating under Cantilever Boundary Condition

    Directory of Open Access Journals (Sweden)

    Hui Li

    2017-01-01

    Full Text Available This research has experimentally investigated the influence on vibration characteristics of thin cantilever cylindrical shell (TCS with hard coating under cantilever boundary condition. Firstly, the theoretical model of TCS with hard coating is established to calculate its natural frequencies and modal shapes so as to roughly understand vibration characteristic of TCS when it is coated with hard coating material. Then, by considering its nonlinear stiffness and damping influences, an experiment system is established to accurately measure vibration parameters of the shell, and the corresponding test methods and identification techniques are also proposed. Finally, based on the measured data, the influences on natural frequencies, modal shapes, damping ratios, and vibration responses of TCS with hard coating are analyzed and discussed in detail. It can be found that hard coating can play an important role in vibration reduction of TCS, and for the most modes of TCS, hard coating will result in the decrease of natural frequencies, but the decreased level is not very big, and its damping effects on the higher frequency range of the shell are weak and ineffective. Therefore, in order to make better use of this coating material, we must carefully choose the concerned antivibration frequency range of the shell; otherwise it may lead to some negative effects.

  8. Experimental evaluation of coating delamination in vinyl coated metal forming

    International Nuclear Information System (INIS)

    Son, Young Ki; Lee, Chan Joo; Kim, Byung Min; Lee, Jung Min; Byoen, Sang Doek; Lee, Soen Bong

    2012-01-01

    In this paper, a new evaluation and prediction method for coating delamination during sheet metal forming is presented. On the basis of the forming limit diagram (FLD), the current study evaluates the delamination of PET coating by using a cross cut specimen, dome test, and rectangular cup drawing test. Dome test specimens were subjected to biaxial, plane strain, and uniaxial deformation modes. Rectangular cup drawing test specimens were subjected to the deep drawing deformation mode, and compression deformation mode. A vinyl coated metal (VCM) sheet consists of three layers of polymer on the sheet metals: a protective film, a PET layer and a PVC layer. The areas with coating delamination were identified, and the results of the evaluation were plotted according to major and minor strain values, depicting coating delamination. The constructed delamination limit diagram (DLD) can be used to determine the forming limit of VCM during the complex press forming process. ARGUS (GOM) was employed to identify the strain value and deformation mode of the delaminated surface after the press forming. After identifying the areas of delamination, the DLD of the PET coating can be constructed in a format similar to that of the FLD. The forming limit of the VCM sheet can be evaluated using the superimposition of the delamination limit strain of the coating onto the FLD of VCM sheet. The experimental results showed that the proposed test method will support the sheet metal forming process design for VCM sheets. The assessment method presented in this study can be used to determine the delamination limit strain under plastic deformation of other polymer coated metals. The experimental results suggested that the proposed testing method is effective in evaluating delamination for specific applications

  9. Experimental evaluation of coating delamination in vinyl coated metal forming

    Energy Technology Data Exchange (ETDEWEB)

    Son, Young Ki; Lee, Chan Joo; Kim, Byung Min [Pusan National Univ., Busan (Korea, Republic of); Lee, Jung Min [Korea Institute of Industrial Technology, Busan (Korea, Republic of); Byoen, Sang Doek [HA Digital Engineering Gr., Seongsan Gu (Korea, Republic of); Lee, Soen Bong [Keimyung Univ., Daegu (Korea, Republic of)

    2012-10-15

    In this paper, a new evaluation and prediction method for coating delamination during sheet metal forming is presented. On the basis of the forming limit diagram (FLD), the current study evaluates the delamination of PET coating by using a cross cut specimen, dome test, and rectangular cup drawing test. Dome test specimens were subjected to biaxial, plane strain, and uniaxial deformation modes. Rectangular cup drawing test specimens were subjected to the deep drawing deformation mode, and compression deformation mode. A vinyl coated metal (VCM) sheet consists of three layers of polymer on the sheet metals: a protective film, a PET layer and a PVC layer. The areas with coating delamination were identified, and the results of the evaluation were plotted according to major and minor strain values, depicting coating delamination. The constructed delamination limit diagram (DLD) can be used to determine the forming limit of VCM during the complex press forming process. ARGUS (GOM) was employed to identify the strain value and deformation mode of the delaminated surface after the press forming. After identifying the areas of delamination, the DLD of the PET coating can be constructed in a format similar to that of the FLD. The forming limit of the VCM sheet can be evaluated using the superimposition of the delamination limit strain of the coating onto the FLD of VCM sheet. The experimental results showed that the proposed test method will support the sheet metal forming process design for VCM sheets. The assessment method presented in this study can be used to determine the delamination limit strain under plastic deformation of other polymer coated metals. The experimental results suggested that the proposed testing method is effective in evaluating delamination for specific applications.

  10. Effect of Annealing Temperature on the Water Contact Angle of PVD Hard Coatings

    Science.gov (United States)

    Yang, Yu-Sen; Cho, Ting-Pin

    2013-01-01

    Various PVD (physical vapor deposition) hard coatings including nitrides and metal-doped diamond-like carbons (Me-DLC) were applied in plastic injection and die-casting molds to improve wear resistance and reduce sticking. In this study, nitrides hcp-AlN (hexagonal close-packed AlN), Cr2N, (CrAl)2N) and Me-DLC (Si-DLC and Cr-DLC) coatings were prepared using a closed field unbalanced magnetron reactive sputtering system. The coatings were annealed in air for 2 h at various temperatures, after which the anti-sticking properties were assessed using water contact angle (WCA) measurements. The as-deposited hcp-AlN, Cr2N and (CrAl)2N coatings exhibit hydrophobic behavior and exhibit respective WCAs of 119°, 106° and 101°. The as-deposited Si-DLC and Cr-DLC coatings exhibit hydrophilic behavior and exhibit respective WCAs of 74° and 88°. The annealed Cr2N and (CrAl)2N coatings exhibit hydrophobic behavior with higher WCAs, while the annealed hcp-AlN, Si-DLC and Cr-DLC coatings are hydrophilic. The increased WCA of the annealed Cr2N and (CrAl)2N coatings is related to their crystal structure and increased roughness. The decreased WCA of the annealed hcp-AlN, Si-DLC and Cr-DLC coatings is related to their crystal structures and has little correlation with roughness. PMID:28811440

  11. Effect of Annealing Temperature on the Water Contact Angle of PVD Hard Coatings.

    Science.gov (United States)

    Yang, Yu-Sen; Cho, Ting-Pin

    2013-08-07

    Various PVD (physical vapor deposition) hard coatings including nitrides and metal-doped diamond-like carbons (Me-DLC) were applied in plastic injection and die-casting molds to improve wear resistance and reduce sticking. In this study, nitrides hcp-AlN (hexagonal close-packed AlN), Cr₂N, (CrAl)₂N) and Me-DLC (Si-DLC and Cr-DLC) coatings were prepared using a closed field unbalanced magnetron reactive sputtering system. The coatings were annealed in air for 2 h at various temperatures, after which the anti-sticking properties were assessed using water contact angle (WCA) measurements. The as-deposited hcp-AlN, Cr₂N and (CrAl)₂N coatings exhibit hydrophobic behavior and exhibit respective WCAs of 119°, 106° and 101°. The as-deposited Si-DLC and Cr-DLC coatings exhibit hydrophilic behavior and exhibit respective WCAs of 74° and 88°. The annealed Cr₂N and (CrAl)₂N coatings exhibit hydrophobic behavior with higher WCAs, while the annealed hcp-AlN, Si-DLC and Cr-DLC coatings are hydrophilic. The increased WCA of the annealed Cr₂N and (CrAl)₂N coatings is related to their crystal structure and increased roughness. The decreased WCA of the annealed hcp-AlN, Si-DLC and Cr-DLC coatings is related to their crystal structures and has little correlation with roughness.

  12. Sealing of hard CrN and DLC coatings with atomic layer deposition.

    Science.gov (United States)

    Härkönen, Emma; Kolev, Ivan; Díaz, Belén; Swiatowska, Jolanta; Maurice, Vincent; Seyeux, Antoine; Marcus, Philippe; Fenker, Martin; Toth, Lajos; Radnoczi, György; Vehkamäki, Marko; Ritala, Mikko

    2014-02-12

    Atomic layer deposition (ALD) is a thin film deposition technique that is based on alternating and saturating surface reactions of two or more gaseous precursors. The excellent conformality of ALD thin films can be exploited for sealing defects in coatings made by other techniques. Here the corrosion protection properties of hard CrN and diamond-like carbon (DLC) coatings on low alloy steel were improved by ALD sealing with 50 nm thick layers consisting of Al2O3 and Ta2O5 nanolaminates or mixtures. In cross sectional images the ALD layers were found to follow the surface morphology of the CrN coatings uniformly. Furthermore, ALD growth into the pinholes of the CrN coating was verified. In electrochemical measurements the ALD sealing was found to decrease the current density of the CrN coated steel by over 2 orders of magnitude. The neutral salt spray (NSS) durability was also improved: on the best samples the appearance of corrosion spots was delayed from 2 to 168 h. On DLC coatings the adhesion of the ALD sealing layers was weaker, but still clear improvement in NSS durability was achieved indicating sealing of the pinholes.

  13. Experimental investigation on hard turning of AISI 4340 steel using cemented coated carbide insert

    Science.gov (United States)

    Pradeep Kumar, J.; Kishore, K. P.; Ranjith Kumar, M.; Saran Karthick, K. R.; Vishnu Gowtham, S.

    2018-02-01

    Hard turning is a developing technology that offers many potential advantages compared to grinding, which remains the standard finishing process for critical hardened surfaces. In this work, an attempt has been made to experimentally investigate hard turning of AISI 4340 steel under wet and dry condition using cemented coated carbide insert. Hardness of the workpiece material is tested using Brinell and Rockwell hardness testers. CNC LATHE and cemented coated carbide inserts of designation CNMG 120408 are used for conducting experimental trials. Significant cutting parameters like cutting speed, feed rate and depth of cut are considered as controllable input parameters and surface roughness (Ra), tool wear are considered as output response parameters. Design of experiments is carried out with the help of Taguchi’s L9 orthogonal array. Results of response parameters like surface roughness and tool wear under wet and dry condition are analysed. It is found that surface roughness and tool wear are higher under dry machining condition when compared to wet machining condition. Feed rate significantly influences the surface roughness followed by cutting speed. Depth of cut significantly influences the tool wear followed by cutting speed.

  14. Solar Absorptance of Cermet Coatings Evaluated

    Science.gov (United States)

    Jaworske, Donald A.

    2004-01-01

    Cermet coatings, molecular mixtures of metal and ceramic, are being considered for the heat inlet surface of solar Stirling convertors. In this application, the key role of the cermet coating is to absorb as much of the incident solar energy as possible. To achieve this objective, the cermet coating has a high solar absorptance value. Cermet coatings are manufactured utilizing sputter deposition, and many different metal and ceramic combinations can be created. The ability to mix metal and ceramic at the atomic level offers the opportunity to tailor the composition, and hence, the optical properties of these coatings. The NASA Glenn Research Center has prepared and characterized a wide variety of cermet coatings utilizing different metals deposited in an aluminum oxide ceramic matrix. In addition, the atomic oxygen durability of these coatings has been evaluated.

  15. Validation of HVOF WC/Co Thermal Spray Coatings as a Replacement for Hard Chrome Plating on Aircraft Landing Gear

    National Research Council Canada - National Science Library

    Sartwell, Bruce

    2004-01-01

    .... This document constitutes the final report on a project to quality high-velocity oxygen-fuel (HVOF) thermal spray WC/Co coatings as a replacement for hard chrome plating on landing gear components...

  16. Characterization of hard nitride and carbide titanium and zirconium coatings on high-speed steel cutting tool inserts

    International Nuclear Information System (INIS)

    Fenske, G.; Kaufherr, N.; Albertson, C.; Mapalo, G.; Nielsen, R.; Kaminsky, M.

    1986-01-01

    Hard nitride and carbide coatings of titanium and zirconium deposited by reactive evaporation and reactive sputtering techniques were characterized by electron microscopy and Auger spectroscopy to determine the effect of coating process on coating composition and microstructure. Analysis of the chemical composition by Auger spectroscopy revealed the coatings were of high purity with slight differences in stoichiometry depending on the coating technique. Both techniques produced coatings with a columnar microstructure. However, the reactive sputtering technique produced coarser (shorter and wider) columnar grains than the reactive evaporation technique. Furthermore, selected area diffraction analysis of reactively sputtered ZrN coatings showed a two-phased zone (hcp Zr and fcc ZrN) near the substrate/coating interface, while TiC coatings deposited by reactive sputtering and evaporation only showed a single-phase region of fcc TiC

  17. Study of surface roughness and flank wear in hard turning of AISI 4140 steel with coated ceramic inserts

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sudhansu Ranjan; Kuma, Amaresh [National Institute of Technology, Jamshedpur (India); Dhupal, Debabrata [Veer Surendra Sai University of Technology, Burla (India)

    2015-10-15

    This experimental investigation deals with dry hard turning of AISI 4140 steel using PVD-TiN coated Al{sub 2}O{sub 3}+TiCN mixed ceramic inserts. The combined effect of cutting parameters (cutting speed, feed and depth of cut) on performance characteristics such as surface roughness and flank wear is explored by Full factorial design (FFD) and analysis of variance (ANOVA). The results show that feed is the principal cutting parameter influencing surface roughness, followed by cutting speed. However, flank wear is affected by the cutting speed and interaction of feed-depth of cut, although depth of cut has not been found statistically significant, but flank wear is an increasing function of depth of cut. Observations are made on the machined surface, and worn tool by Scanning electron microscope (SEM) to establish the process. Abrasion was the major wear mechanism found during hard turning within the studied range. The effect of tool wear on surface roughness was also studied. The experimental data were analyzed to predict the optimal range of surface roughness and flank wear. Based on Response surface methodology (RSM), mathematical models were developed for surface roughness (Ra) and flank wear (VB) with 95% confidence level. Finally, under optimum cutting conditions (obtained by response optimization technique), tool life was evaluated to perform cost analysis for justifying the economic viability of coated ceramic inserts in hard turning. The estimated machining cost per part for TiN coated ceramic was found to be lower (Rs. 12.31) because of higher tool life (51 min), which results in the reduction of downtime and increase in savings.

  18. Study of surface roughness and flank wear in hard turning of AISI 4140 steel with coated ceramic inserts

    International Nuclear Information System (INIS)

    Das, Sudhansu Ranjan; Kuma, Amaresh; Dhupal, Debabrata

    2015-01-01

    This experimental investigation deals with dry hard turning of AISI 4140 steel using PVD-TiN coated Al_2O_3+TiCN mixed ceramic inserts. The combined effect of cutting parameters (cutting speed, feed and depth of cut) on performance characteristics such as surface roughness and flank wear is explored by Full factorial design (FFD) and analysis of variance (ANOVA). The results show that feed is the principal cutting parameter influencing surface roughness, followed by cutting speed. However, flank wear is affected by the cutting speed and interaction of feed-depth of cut, although depth of cut has not been found statistically significant, but flank wear is an increasing function of depth of cut. Observations are made on the machined surface, and worn tool by Scanning electron microscope (SEM) to establish the process. Abrasion was the major wear mechanism found during hard turning within the studied range. The effect of tool wear on surface roughness was also studied. The experimental data were analyzed to predict the optimal range of surface roughness and flank wear. Based on Response surface methodology (RSM), mathematical models were developed for surface roughness (Ra) and flank wear (VB) with 95% confidence level. Finally, under optimum cutting conditions (obtained by response optimization technique), tool life was evaluated to perform cost analysis for justifying the economic viability of coated ceramic inserts in hard turning. The estimated machining cost per part for TiN coated ceramic was found to be lower (Rs. 12.31) because of higher tool life (51 min), which results in the reduction of downtime and increase in savings.

  19. Oxidation resistance of CrN/(Cr,V)N hard coatings deposited by DC magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Panjan, P., E-mail: peter.panjan@ijs.si [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Drnovšek, A.; Kovač, J.; Gselman, P. [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Bončina, T. [University of Maribor, Faculty of Mechanical Engineering, Smetanova 17, 2000 Maribor (Slovenia); Paskvale, S.; Čekada, M.; Kek Merl, D.; Panjan, M. [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia)

    2015-09-30

    In recent years vanadium-doped hard coatings have become available as possible candidates for self-lubrication at high temperatures. Their low coefficient of friction has mainly been attributed to the formation of the V{sub 2}O{sub 5} phase. However, the formation of vanadium oxides must be controlled by the out-diffusion of vanadium in order to achieve the combination of a low coefficient of friction and good mechanical properties for the protective coatings. In this work the application of a nanolayer of CrN/(Cr,V)N hard coating was proposed as a way to better control the out-diffusion of vanadium, while the topmost chromium oxide layer acts as barrier for the vanadium diffusion. However, the aim of this investigation was not only to focus on the formation of the oxide layer. Special attention was given to the oxidation process that takes place at the growth defects, where we observed a strong diffusion of vanadium taking place. The CrN/(Cr,V)N nanolayer coatings were deposited by DC unbalanced magnetron sputtering in an CC800/9 (CemeCon) industrial unit. The vanadium concentration in the (Cr,V)N layers was varied in the range 1.0–11.5 at.%. - Highlights: • Oxidation processes of CrN/(Cr,V)N nanolayers with vanadium content were investigated. • The CrN/(Cr,V)N hard layers were oxidized at high temperature in O2 atm. • The top chromium oxide layer acts as a diffusion barrier for vanadium ions during oxidation. • Important role of growth defects during the oxidation process is demonstrated.

  20. Hard and transparent hybrid polyurethane coatings using in situ incorporation of calcium carbonate nanoparticles

    International Nuclear Information System (INIS)

    Yao Lu; Yang Jie; Sun Jing; Cai Lifang; He Linghao; Huang Hui; Song Rui; Hao Yongmei

    2011-01-01

    Highlights: → In situ mineralization via gas diffusion was adopted for a good dispersion of calcium carbonate nanoparticles in the polymeric PU matrix. → Hybrid films with high dispersion, transparency, robust and thermal stability can be obtained by controlling the CaCO 3 loading. → The hybrid films display a significant improvement in its water resistance, surface hardness, scratch resistance and flexibility, with the introduction of CaCO 3 , and all coatings exhibited excellent chemical resistance and adhesion. - Abstract: The combination of hardness, scratch resistance, and flexibility is a highly desired feature in many coating applications. The aim of this study is to achieve this goal through the in situ introduction of an unmodified calcium carbonate (CaCO 3 ) into a water-soluble polyurethane (PU) matrix. Smooth and (semi-) transparent films were prepared from both the neat PU and the CaCO 3 -filled composites. As evidenced by the measurements from scanning electron microscopy (SEM), optical microscopy, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), hybrid films with high dispersion, transparency, robustness and thermal stability could be obtained by controlling the CaCO 3 loading. The storage modulus could increase from 441 MPa of neat PU matrix to 1034 MPa of hybrid film containing 2% (w/w) CaCO 3 . In addition, the same hybrid films displayed a significant improvement in its water resistance. In this case, the water-uptake ratio decreased from 41.54% of PU to 2.21% of hybrid film containing 2% (w/w) CaCO 3 . Moreover, with the introduction of CaCO 3 , conventional coating characterization methods demonstrated an increase in the surface hardness, scratch resistance and flexibility, and all coatings exhibited excellent chemical resistance and adhesion.

  1. Oxidation resistance of CrN/(Cr,V)N hard coatings deposited by DC magnetron sputtering

    International Nuclear Information System (INIS)

    Panjan, P.; Drnovšek, A.; Kovač, J.; Gselman, P.; Bončina, T.; Paskvale, S.; Čekada, M.; Kek Merl, D.; Panjan, M.

    2015-01-01

    In recent years vanadium-doped hard coatings have become available as possible candidates for self-lubrication at high temperatures. Their low coefficient of friction has mainly been attributed to the formation of the V_2O_5 phase. However, the formation of vanadium oxides must be controlled by the out-diffusion of vanadium in order to achieve the combination of a low coefficient of friction and good mechanical properties for the protective coatings. In this work the application of a nanolayer of CrN/(Cr,V)N hard coating was proposed as a way to better control the out-diffusion of vanadium, while the topmost chromium oxide layer acts as barrier for the vanadium diffusion. However, the aim of this investigation was not only to focus on the formation of the oxide layer. Special attention was given to the oxidation process that takes place at the growth defects, where we observed a strong diffusion of vanadium taking place. The CrN/(Cr,V)N nanolayer coatings were deposited by DC unbalanced magnetron sputtering in an CC800/9 (CemeCon) industrial unit. The vanadium concentration in the (Cr,V)N layers was varied in the range 1.0–11.5 at.%. - Highlights: • Oxidation processes of CrN/(Cr,V)N nanolayers with vanadium content were investigated. • The CrN/(Cr,V)N hard layers were oxidized at high temperature in O2 atm. • The top chromium oxide layer acts as a diffusion barrier for vanadium ions during oxidation. • Important role of growth defects during the oxidation process is demonstrated.

  2. Highly hard yet toughened bcc-W coating by doping unexpectedly low B content

    KAUST Repository

    Yang, Lina

    2017-08-18

    Either hardness or toughness has been the core interest in scientific exploration and technological pursuit for a long time. However, it is still a big challenge to enhance the hardness and toughness at the same time, since the improvement of one side is always at the expense of the other one. Here, we have succeeded in dealing with this pair of conflict based on tungsten (W) coating by doping boron (B) via magnetron co-sputtering. The results reveal that the introduction of low concentrations of B (6.3 at. %), in the doping regime, leads to the formation of W(B) supersaturated solid solution with refined grains. Meanwhile, the doping-induced higher compressive stress, higher H/E* and denser microstructure result in a surprising combination of improved hardness (2 × larger than pure W) and superior toughness (higher crack formation threshold compared to pure W). We believe this is an innovative sight to design new generation of transition-metal-based multifunctional coatings. Besides, our results are applicable for industrial application because it can be realized by simple manufacturing approaches, e.g. magnetron sputtering technology.

  3. Identifying the optimal HVOF spray parameters to attain minimum porosity and maximum hardness in iron based amorphous metallic coatings

    Directory of Open Access Journals (Sweden)

    S. Vignesh

    2017-04-01

    Full Text Available Flow based Erosion – corrosion problems are very common in fluid handling equipments such as propellers, impellers, pumps in warships, submarine. Though there are many coating materials available to combat erosion–corrosion damage in the above components, iron based amorphous coatings are considered to be more effective to combat erosion–corrosion problems. High velocity oxy-fuel (HVOF spray process is considered to be a better process to coat the iron based amorphous powders. In this investigation, iron based amorphous metallic coating was developed on 316 stainless steel substrate using HVOF spray technique. Empirical relationships were developed to predict the porosity and micro hardness of iron based amorphous coating incorporating HVOF spray parameters such as oxygen flow rate, fuel flow rate, powder feed rate, carrier gas flow rate, and spray distance. Response surface methodology (RSM was used to identify the optimal HVOF spray parameters to attain coating with minimum porosity and maximum hardness.

  4. Evaluation of using edible coating and ripening on Dangke, a traditional cheese of Indonesia

    Directory of Open Access Journals (Sweden)

    Malaka, R.

    2017-03-01

    Full Text Available Dangke is a traditional soft cheese from Enrekang, South Sulawesi Indonesia which is produced through heat denaturation at 85°C and enzymatic coagulation using papaya latex. The quality, microstructure and storage life of the cheese are affected by several factors such as denaturation temperature, enzyme concentration, moulding pressure, coating, and ripening. The objective of this study was to evaluated of using edible coating and ripening on Dangke cheese. The experiment was conducting using factorial design with five replications. The experimental variables were the type of edible coating used (agar, CMC and bee wax and the length of ripening (10, 20 and 30 days. Parameter was measured hardness, microstructure, and sensory evaluation. The overall result indicated that the use of edible coating can extend the shelf life, increase hardness, and more compact microstructure. Sensory evaluation also indicated that the cheese coated with film forming edible materials had had white color, more milk like smell (smelly milk, and smoother texture.

  5. Improvement of Wear Performance of Nano-Multilayer PVD Coatings under Dry Hard End Milling Conditions Based on Their Architectural Development

    Directory of Open Access Journals (Sweden)

    Shahereen Chowdhury

    2018-02-01

    Full Text Available The TiAlCrSiYN-based family of PVD (physical vapor deposition hard coatings was specially designed for extreme conditions involving the dry ultra-performance machining of hardened tool steels. However, there is a strong potential for further advances in the wear performance of the coatings through improvements in their architecture. A few different coating architectures (monolayer, multilayer, bi-multilayer, bi-multilayer with increased number of alternating nano-layers were studied in relation to cutting-tool life. Comprehensive characterization of the structure and properties of the coatings has been performed using XRD, SEM, TEM, micro-mechanical studies and tool-life evaluation. The wear performance was then related to the ability of the coating layer to exhibit minimal surface damage under operation, which is directly associated with the various micro-mechanical characteristics (such as hardness, elastic modulus and related characteristics; nano-impact; scratch test-based characteristics. The results presented exhibited that a substantial increase in tool life as well as improvement of the mechanical properties could be achieved through the architectural development of the coatings.

  6. The effect of immersion time to low carbon steel hardness and microstructure with hot dip galvanizing coating method

    Science.gov (United States)

    Hakim, A. A.; Rajagukguk, T. O.; Sumardi, S.

    2018-01-01

    Along with developing necessities of metal materials, these rise demands of quality improvements and material protections especially the mechanical properties of the material. This research used hot dip galvanizing coating method. The objectives of this research were to find out Rockwell hardness (HRb), layer thickness, micro structure and observation with Scanning Electron Microscope (SEM) from result of coating by using Hot Dip Galvanizing coating method with immersion time of 3, 6, 9, and 12 minutes at 460°C. The result shows that Highest Rockwell hardness test (HRb) was at 3 minutes immersion time with 76.012 HRb. Highest thickness result was 217.3 μm at 12 minutes immersion. Microstructure test result showed that coating was formed at eta, zeta, delta and gamma phases, while Scanning Electron Microscope (SEM) showed Fe, Zn, Mn, Si and S elements at the specimens after coating.

  7. Development of method for evaluating cell hardness and correlation between bacterial spore hardness and durability

    Directory of Open Access Journals (Sweden)

    Nakanishi Koichi

    2012-06-01

    Full Text Available Abstract Background Despite the availability of conventional devices for making single-cell manipulations, determining the hardness of a single cell remains difficult. Here, we consider the cell to be a linear elastic body and apply Young’s modulus (modulus of elasticity, which is defined as the ratio of the repulsive force (stress in response to the applied strain. In this new method, a scanning probe microscope (SPM is operated with a cantilever in the “contact-and-push” mode, and the cantilever is applied to the cell surface over a set distance (applied strain. Results We determined the hardness of the following bacterial cells: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and five Bacillus spp. In log phase, these strains had a similar Young’s modulus, but Bacillus spp. spores were significantly harder than the corresponding vegetative cells. There was a positive, linear correlation between the hardness of bacterial spores and heat or ultraviolet (UV resistance. Conclusions Using this technique, the hardness of a single vegetative bacterial cell or spore could be determined based on Young’s modulus. As an application of this technique, we demonstrated that the hardness of individual bacterial spores was directly proportional to heat and UV resistance, which are the conventional measures of physical durability. This technique allows the rapid and direct determination of spore durability and provides a valuable and innovative method for the evaluation of physical properties in the field of microbiology.

  8. In-Service Evaluation of HVOF Coated Main Landing Gear on Navy P-3 Aircraft

    Science.gov (United States)

    Devereaux, jon L.; Forrest, Clint

    2008-01-01

    Due to the environmental and health concerns with Electroplated Hard Chrome (EHC), the Hard Chrome Alternatives Team (HCAT) has been working to provide an alternative wear coating for EHC. The US Navy selected Tungsten-Carbide Cobalt (WC- 17Co) High Velocity Oxy-Fuel (HVOF) thermal spray coating for this purpose and completed service evaluations on select aircraft components to support the HCAT charter in identifying an alternative wear coating for chrome plating. Other benefits of WC-Co thermal spray coatings over EHC are enhanced corrosion resistance, improved durability, and exceptional wear properties. As part of the HCAT charter and to evaluate HVOF coatings on operational Navy components, the P-3 aircraft was selected for a service evaluation to determine the coating durability as compared to chrome plating. In April 1999, a VP-30 P-3 aircraft was outfitted with a right-hand Main Landing Gear (MLG) shock strut coated with WCCo HYOF thermal spray applied to the piston barrel and four axle journals. The HVOF coating on the piston barrel and axle journals was applied by Southwest United Industries, Inc. This HVOF coated strut assembly has since completed 6,378 landings. Teardown analysis .for this WC-Co HVOF coated MLG asset is significant in assessing the durability of this wear coating in service relative to EHC and to substantiate Life Cycle Cost (LCC) data to support a retrograde transition from EHC to HVOF thermal spray coatings. Findings from this teardown analysis may also benefit future transitions to HVOF thermal spray coatings by identifying enhancements to finishing techniques, mating bearing and liner material improvements, improved seal materials, and improvements in HVOF coating selection.

  9. Characterization of hard coatings produced by laser cladding using laser-induced breakdown spectroscopy technique

    Energy Technology Data Exchange (ETDEWEB)

    Varela, J.A.; Amado, J.M.; Tobar, M.J.; Mateo, M.P.; Yañez, A.; Nicolas, G., E-mail: gines@udc.es

    2015-05-01

    Highlights: • Chemical mapping and profiling by laser-induced breakdown spectroscopy (LIBS) of coatings produced by laser cladding. • Production of laser clads using tungsten carbide (WC) and nickel based matrix (NiCrBSi) powders. • Calibration by LIBS of hardfacing alloys with different WC concentrations. - Abstract: Protective coatings with a high abrasive wear resistance can be obtained from powders by laser cladding technique, in order to extend the service life of some industrial components. In this work, laser clad layers of self-fluxing NiCrBSi alloy powder mixed with WC powder have been produced on stainless steel substrates of austenitic type (AISI 304) in a first step and then chemically characterized by laser-induced breakdown spectroscopy (LIBS) technique. With the suitable laser processing parameters (mainly output power, beam scan speed and flow rate) and powders mixture proportions between WC ceramics and NiCrBSi alloys, dense pore free layers have been obtained on single tracks and on large areas with overlapped tracks. The results achieved by LIBS technique and applied for the first time to the analysis of laser clads provided the chemical composition of the tungsten carbides in metal alloy matrix. Different measurement modes (multiple point analyses, depth profiles and chemical maps) have been employed, demonstrating the usefulness of LIBS technique for the characterization of laser clads based on hardfacing alloys. The behavior of hardness can be explained by LIBS maps which evidenced the partial dilution of some WC spheres in the coating.

  10. Degradation and in vitro cell–material interaction studies on hydroxyapatite-coated biodegradable porous iron for hard tissue scaffolds

    Directory of Open Access Journals (Sweden)

    Nurizzati Mohd Daud

    2014-10-01

    Full Text Available This paper describes degradation and cell–material interaction studies on hydroxyapatite (HA-coated biodegradable porous iron proposed for hard tissue scaffolds. Porous iron scaffolds are expected to serve as an ideal platform for bone regeneration. To couple their inherent mechanical strength, pure HA and HA/poly(ε-caprolactone (HA/PCL were coated onto porous iron using dip coating technique. The HA/PCL mixture was prepared to provide a more stable and flexible coating than HA alone. Degradation of the samples was evaluated by weight loss and potentiodynamic polarisation. Human skin fibroblast (HSF and human mesenchymal stem cells (hMSC were put in contact with the samples and their interaction was observed. Results showed that coated samples degraded ∼10 times slower (0.002 mm/year for HA/PCL-Fe, 0.003 mm/year for HA-Fe than the uncoated ones (0.031 mm/year, indicating an inhibition effect of the coating on degradation. Both HSF and hMSC maintained high viability when in contact with the coated samples (100–110% control for hMSC during 2–5 days of incubation, indicating the effect of HA in enhancing cytocompatibility of the surface. This study provided early evidence of the potential translation of biodegradable porous iron scaffolds for clinical use in orthopedic surgery. However, further studies including in vitro and in vivo tests are necessary.

  11. Effect of Substrate Bias on Friction Coefficient, Adhesion Strength and Hardness of TiN-COATED Tool Steel

    Science.gov (United States)

    Hamzah, Esah; Ali, Mubarak; Toff, Mohd Radzi Hj. Mohd

    In the present study, TiN coatings have been deposited on D2 tool steel substrates by using cathodic arc physical vapor deposition technique. The objective of this research work is to determine the usefulness of TiN coatings in order to improve the micro-Vickers hardness and friction coefficient of TiN coating deposited on D2 tool steel, which is widely used in tooling applications. A Pin-on-Disc test was carried out to study the coefficient of friction versus sliding distance of TiN coating deposited at various substrate biases. The standard deviation parameter during tribo-test result showed that the coating deposited at substrate bias of -75 V was the most stable coating. A significant increase in micro-Vickers hardness was recorded, when substrate bias was reduced from -150 V to zero. Scratch tester was used to compare the critical loads for coatings deposited at different bias voltages and the adhesion achievable was demonstrated with relevance to the various modes, scratch macroscopic analysis, critical load, acoustic emission and penetration depth. A considerable improvement in TiN coatings was observed as a function of various substrate bias voltages.

  12. Investigation of stand-off distance effect on structure, adhesion and hardness of copper coatings obtained by the APS technique

    Science.gov (United States)

    Masoumeh, Goudarzi; Shahrooz, Saviz; Mahmood, Ghoranneviss; Ahmad, Salar Elahi

    2018-03-01

    The outbreak of the disease and infection in the hospital environment and medical equipment is one of the concerns of modern life. One of the effective ways for preventing and reducing the complications of infections is modification of the surface. Here, the handmade atmospheric plasma spray system is used for accumulating copper as an antibacterial agent on the 316L stainless steel substrate, which applies to hospital environment and medical equipment. As a durable coating with proper adhesion is needed on the substrate, the effect of stand-off distance (SOD) which is an important parameter of the spray on the microstructure, the hardness and adhesion of the copper coating on the 316L stainless steel were investigated. The structure and phase composition of copper depositions were investigated using scanning electron microscopy and X-ray diffraction. The adhesion and hardness of depositions are evidenced using the cross cut tester and Vickers hardness tester, respectively. The findings confirm that the voids in the coatings increase with increasing SOD, which leads to decreasing the hardness of coatings and also the adhesion strength between depositions and substrate. In addition, by increasing the SOD, the oxygen content and the size of grains in the lamellae (fine structure) of coatings also increase.

  13. A proposal for an unusually stiff and moderately ductile hard coating material: Mo2BC

    International Nuclear Information System (INIS)

    Emmerlich, J; Music, D; Braun, M; Fayek, P; Schneider, J M; Munnik, F

    2009-01-01

    The elastic properties of Mo 2 BC were studied using ab initio calculations. The calculated bulk modulus of 324 GPa is 45% larger than that of Ti 0.25 Al 0.75 N and 14% smaller than that of c-BN, indicating a highly stiff material. The bulk modulus (B) to shear modulus (G) ratio is 1.72 at the transition from brittle to ductile behaviour. This, in combination with a positive Cauchy pressure (c 12 - c 44 ), suggests moderate ductility. When compared with a typical hard protective coating such as Ti 0.25 Al 0.75 N (B = 178 GPa; B/G = 1.44; negative Cauchy pressure), Mo 2 BC displays considerable potential as protective coating for metal cutting applications. In order to test this proposal, Mo 2 BC thin films were synthesized using dc magnetron sputtering from three plasma sources on Al 2 O 3 (0 0 0 1) at a substrate temperature of ∼900 0 C. The calculated lattice parameters are in good agreement with values determined from x-ray diffraction. The measured Young's modulus values of ∼460 ± 21 GPa are in excellent agreement with the 470 GPa value obtained by calculations. Scanning probe microscopy imaging of the residual indent revealed no evidence for crack formation as well as significant pile-up, which is consistent with the moderate plasticity predicted. The apparent contradiction between moderate ductility on the one hand and indentation hardness values of 29 GPa can be understood by considering the electronic structure particularly the extreme anisotropy. The presence of stiff Mo-C and Mo-B layers with metallic interlayer bonding enables this intriguing and unexpected property combination.

  14. A new electrothermal-chemical method for metals, carbides, and ceramics hard coating: Experiment and theory

    Energy Technology Data Exchange (ETDEWEB)

    Zoler, D.; Bruma, C.; Cuperman, S.

    1999-07-01

    A new method and an experimental device for powders of metals, carbides and ceramics coating of various substrates are presented. The powder-particles are accelerated and heated by a mixture of plasma and gases resulted from the burning of an energetic (propellant). The operating prototype already allows one to obtain coatings of metals, carbides and ceramics. Some of the coatings obtained, especially those by carbides powders, indicate even at the present stage of research, properties (as hardness, porosity) which are comparable to those provided by the presently industrial methods in use. The accelerating-heating agent in the device (the plasma-gas mixture) is characterized by very high densities (up to 120 kg/m{sup 3}), temperatures (up to 20,000 K) and velocities (more than 1,500 m/s). Due to these characteristics, the powder particles are accelerated to velocities significantly higher than those reached in other coating devices as, for example, the detonation (D) gun. Some preliminary experimental data show that the accelerated particle can reach velocities higher than 1,000 m/s. In parallel, in order to better understand the phenomena taking place inside the device and to determine the optimal process parameters leading to high quality coatings an appropriate theoretical model was developed. The model is able to describe the complex processes of plasma-gas-propellant interaction, gas flow and powder particles heating and acceleration. The model gives a detailed description of the gas, propellant and accelerated particle parameters, their spatial distribution and temporal evolution; predicts their dependence on the values of some input quantities such as: the plasma energy, propellant characteristics and accelerated particles type and geometry. The computational results the authors obtained show that, indeed, during the acceleration process the particles are heated, melted and eventually vaporized. One of the most interesting theoretical results is that the

  15. Characterization of hard coatings produced by laser cladding using laser-induced breakdown spectroscopy technique

    Science.gov (United States)

    Varela, J. A.; Amado, J. M.; Tobar, M. J.; Mateo, M. P.; Yañez, A.; Nicolas, G.

    2015-05-01

    Protective coatings with a high abrasive wear resistance can be obtained from powders by laser cladding technique, in order to extend the service life of some industrial components. In this work, laser clad layers of self-fluxing NiCrBSi alloy powder mixed with WC powder have been produced on stainless steel substrates of austenitic type (AISI 304) in a first step and then chemically characterized by laser-induced breakdown spectroscopy (LIBS) technique. With the suitable laser processing parameters (mainly output power, beam scan speed and flow rate) and powders mixture proportions between WC ceramics and NiCrBSi alloys, dense pore free layers have been obtained on single tracks and on large areas with overlapped tracks. The results achieved by LIBS technique and applied for the first time to the analysis of laser clads provided the chemical composition of the tungsten carbides in metal alloy matrix. Different measurement modes (multiple point analyses, depth profiles and chemical maps) have been employed, demonstrating the usefulness of LIBS technique for the characterization of laser clads based on hardfacing alloys. The behavior of hardness can be explained by LIBS maps which evidenced the partial dilution of some WC spheres in the coating.

  16. Abrasion resistant low friction and ultra-hard magnetron sputtered AlMgB14 coatings

    Science.gov (United States)

    Grishin, A. M.

    2016-04-01

    Hard aluminum magnesium boride films were fabricated by RF magnetron sputtering from a single stoichiometric AlMgB14 ceramic target. X-ray amorphous AlMgB14 films are very smooth. Their roughness does not exceed the roughness of Si wafer and Corning glass used as the substrates. Dispersion of refractive index and extinction coefficient were determined within 300 to 2500 nm range for the film deposited onto Corning glass. Stoichiometric in-depth compositionally homogeneous 2 μm thick films on the Si(100) wafer possess the peak values of nanohardness 88 GPa and Young’s modulus 517 GPa at the penetration depth of 26 nm and, respectively, 35 GPa and 275 GPa at 200 nm depth. Friction coefficient was found to be 0.06. The coating scratch adhesion strength of 14 N was obtained as the first chipping of the coating whereas its spallation failure happened at 21 N. These critical loads and the work of adhesion, estimated as high as 18.4 J m-2, surpass characteristics of diamond like carbon films deposited onto tungsten carbide-cobalt (WC-Co) substrates.

  17. Thermal Phenomena in the Friction Process of the TG15 - Hard Anodic Coating Couple

    Directory of Open Access Journals (Sweden)

    Służałek G.

    2016-09-01

    Full Text Available The paper presents a one-dimensional model of heat conduction in a couple consisting of a cylinder made of a sliding plastic material, TG15, and a cuboid made of alloy AW 6061 coated with a hard anodic coating, where the couple is heated with the heat generated during friction. TG15 is a composite material based on polytetrafluoroethylene (PTFE with a 15% graphite filler, used for piston rings in oil-free air-compressors. Measurement of temperature in the friction zone is extremely important for the understanding and analysis of the phenomena occurring therein. It is practically impossible to introduce a temperature sensor in such a place. Therefore, the interaction taking place in such a couple was modelled using numerical methods. In order to simplify and accelerate the calculations, a one-dimensional model and constant thermophysical parameters of the materials participating in friction were adopted. To solve the proposed model, the finite difference method was used (FDM. The resultant system of equations was solved by means of an explicit scheme.

  18. Evaluation of Treatments to Reduce Hardness of Agave americana Core

    Directory of Open Access Journals (Sweden)

    José A. Ramírez

    2006-01-01

    Full Text Available Agave americana contains inulin as storage carbohydrate. Therefore, agave is interesting to be used for the extraction of inulin by pressing. The yield of the process is low due to the high hardness of the core. The objective of this work was to evaluate pretreatments to reduce the hardness in the process of obtaining inulin by pressing. Treatments with water, sulphuric acid 1 % (by mass or sodium hydroxide 1 % (by mass were tested and optimized. The pretreatment of the core of A. americana with sulphuric acid 1 % allowed the reduction of hardness from 30 000 g to 2000 g of breaking force. The mathematical model obtained predicts an optimum processing at 84 °C during 75 min. The treatment with sulphuric acid 1 % also allows white core of A. americana to be obtained, while the other treatments provide yellow core. These results open a good alternative to obtain value added products from this resource.

  19. Utility of tantalum (Ta) coating to improve surface hardness in vitro bioactivity and biocompatibility of Co–Cr

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Vuong-Hung [WCU Hybrid Materials Program, Department of Materials Science and Engineering, Seoul National University, Seoul, 151-742 (Korea, Republic of); Advanced Institute for Science and Technology (AIST), Hanoi University of Science and Technology (HUST), No 1, Dai Co Viet Road, Ha Noi (Viet Nam); Lee, Seung-Hee; Li, Yuanlong; Kim, Hyoun-Ee [WCU Hybrid Materials Program, Department of Materials Science and Engineering, Seoul National University, Seoul, 151-742 (Korea, Republic of); Shin, Kwan-Ha [Department of Dental Laboratory Science and Engineering, Korea University, Seoul, 136-703 (Korea, Republic of); Koh, Young-Hag, E-mail: kohyh@korea.ac.kr [Department of Dental Laboratory Science and Engineering, Korea University, Seoul, 136-703 (Korea, Republic of)

    2013-06-01

    This study reports the utility of tantalum (Ta) coating for improving the surface hardness, in vitro bioactivity and biocompatibility of Co–Cr implants. The use of direct current sputtering allowed for the deposition of a dense and uniform Ta film onto a Co–Cr substrate, which was composed of β-phase Ta grains. This hard Ta coating significantly improved the surface hardness of the Co–Cr by a factor of > 2.3. In addition, the Ta-deposited Co–Cr substrate showed a vigorous precipitation of apatite crystals on its surface after 4 weeks of immersion in simulated body fluid, suggesting its excellent in vitro bioactivity. This bioactive Ta coating led to a considerable improvement in the in vitro biocompatibility of the Co–Cr, which was assessed in terms of the attachment, proliferation and differentiation of pre-osteoblasts (MC3T3-E1). - Highlights: • Dense and uniform Ta film was deposited onto a Co–Cr substrate using DC sputtering. • The Ta coating significantly enhanced the surface hardness of the Co–Cr. • The in vitro biocompatibility of the Co–Cr was also significantly improved.

  20. Utility of tantalum (Ta) coating to improve surface hardness in vitro bioactivity and biocompatibility of Co–Cr

    International Nuclear Information System (INIS)

    Pham, Vuong-Hung; Lee, Seung-Hee; Li, Yuanlong; Kim, Hyoun-Ee; Shin, Kwan-Ha; Koh, Young-Hag

    2013-01-01

    This study reports the utility of tantalum (Ta) coating for improving the surface hardness, in vitro bioactivity and biocompatibility of Co–Cr implants. The use of direct current sputtering allowed for the deposition of a dense and uniform Ta film onto a Co–Cr substrate, which was composed of β-phase Ta grains. This hard Ta coating significantly improved the surface hardness of the Co–Cr by a factor of > 2.3. In addition, the Ta-deposited Co–Cr substrate showed a vigorous precipitation of apatite crystals on its surface after 4 weeks of immersion in simulated body fluid, suggesting its excellent in vitro bioactivity. This bioactive Ta coating led to a considerable improvement in the in vitro biocompatibility of the Co–Cr, which was assessed in terms of the attachment, proliferation and differentiation of pre-osteoblasts (MC3T3-E1). - Highlights: • Dense and uniform Ta film was deposited onto a Co–Cr substrate using DC sputtering. • The Ta coating significantly enhanced the surface hardness of the Co–Cr. • The in vitro biocompatibility of the Co–Cr was also significantly improved

  1. Annual Report - Compatibility of ZDDP and ionic liquid anti-wear additives with hard coatings for engine lubrications

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhou, Yan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Leonard, Donovan N [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Meyer, III, Harry M [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Luo, Huimin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-03-01

    The objectives for this considerations described here are to; investigate the compatibility of engine lubricant antiwear (AW) additives, specifically conventional zinc dialkyldithiophosphate (ZDDP) and newly developed ionic liquids (ILs), with selected commercial hard coatings, and provide fundamental understanding to guide future development of engine lubricants.

  2. Influence of hardness and roughness on the tribological performance of TiC/a-C nanocomposite coatings

    NARCIS (Netherlands)

    Shaha, K. P.; Pei, Y. T.; Martinez Martinez, D.; De Hosson, J. Th. M.

    2010-01-01

    The influence of the hardness of counterface materials on the tribological behavior of TiC/a-C nanocomposite coatings exhibiting various surface roughness was examined by using a ball on a disc configuration in humid air. While sliding against 100Cr6 steel balls, the steady state coefficient of

  3. A synthetic dataset for evaluating soft and hard fusion algorithms

    Science.gov (United States)

    Graham, Jacob L.; Hall, David L.; Rimland, Jeffrey

    2011-06-01

    There is an emerging demand for the development of data fusion techniques and algorithms that are capable of combining conventional "hard" sensor inputs such as video, radar, and multispectral sensor data with "soft" data including textual situation reports, open-source web information, and "hard/soft" data such as image or video data that includes human-generated annotations. New techniques that assist in sense-making over a wide range of vastly heterogeneous sources are critical to improving tactical situational awareness in counterinsurgency (COIN) and other asymmetric warfare situations. A major challenge in this area is the lack of realistic datasets available for test and evaluation of such algorithms. While "soft" message sets exist, they tend to be of limited use for data fusion applications due to the lack of critical message pedigree and other metadata. They also lack corresponding hard sensor data that presents reasonable "fusion opportunities" to evaluate the ability to make connections and inferences that span the soft and hard data sets. This paper outlines the design methodologies, content, and some potential use cases of a COIN-based synthetic soft and hard dataset created under a United States Multi-disciplinary University Research Initiative (MURI) program funded by the U.S. Army Research Office (ARO). The dataset includes realistic synthetic reports from a variety of sources, corresponding synthetic hard data, and an extensive supporting database that maintains "ground truth" through logical grouping of related data into "vignettes." The supporting database also maintains the pedigree of messages and other critical metadata.

  4. Phenolics in the seed coat of wild soybean (Glycine soja) and their significance for seed hardness and seed germination.

    Science.gov (United States)

    Zhou, San; Sekizaki, Haruo; Yang, Zhihong; Sawa, Satoko; Pan, Jun

    2010-10-27

    Hardseededness in annual wild soybean (Glycine soja Sieb. Et Zucc.) is a valuable trait that affects the germination, viability, and quality of stored seeds. Two G. soja ecotypes native to Shandong Province of China have been used to identify the phenolics in the seed coat that correlate with the seed hardness and seed germination. Three major phenolics from the seed coat were isolated and identified as epicatechin, cyanidin 3-O-glucoside, and delphinidin 3-O-glucoside. Of the three phenolics, only the change of epicatechin exhibited a significant positive correlation with the change of hard seed percentages both under different water conditions during seed development and under different gas conditions during seed storage. Epicatechin also reveals a hormesis-like effect on the seed germination of G. soja. Epicatechin is suggested to be functionally related to coat-imposed hardseededness in G. soja.

  5. properties of Cr(C,N) hard coatings deposited in Ar-C2H2-N2 plasma

    International Nuclear Information System (INIS)

    Macek, M.; Cekada, M.; Kek, D.; Panjan, P.

    2002-01-01

    Mechanical properties, microstructure and the average chemical composition of Cr(C,N) hard coatings deposited in Ar-C 2 H 2 -N 2 plasma strongly depends on the partial pressure of the reactive gases (N 2 , C 2 H 2 ) and on the type of the deposition equipment. In this study we report on the properties of Cr(C,N) hard coatings deposited by means of the triode ion plating in the BAI 730 apparatus and those prepared by sputter deposition in Balzers Sputron in the pressure range from 0.12 Pa (pure Ar) up to 0.35 Pa with different ratios (0-100%) between C 2 H 2 and N 2 . At first mechanical properties (microhardness and adhesion) of coatings were analyzed on the common way. Internal stress was measured by the radius of substrate curvature. Chemical composition of coatings was analyzed by means of AES while the Raman and XPS spectroscopy was used to determined the nature of carbon bonding in the Cr(C,N) films. Microstructure was determined by XRD as well as by means of TEM and TED. Chemical state of various elements in the coating has been studied by XPS. The ratio of the carbide bond (C-Cr) against the C-C and C-H bonds was calculated. The existence of the graphite phase in some Cr(C,N) coatings was confirmed by Raman spectroscopy. (Authors)

  6. Diamond-like carbon coatings enhance scratch resistance of bearing surfaces for use in joint arthroplasty: hard substrates outperform soft.

    Science.gov (United States)

    Roy, Marcel E; Whiteside, Leo A; Katerberg, Brian J

    2009-05-01

    The purpose of this study was to test the hypotheses that diamond-like carbon (DLC) coatings will enhance the scratch resistance of a bearing surface in joint arthroplasty, and that a hard ceramic substrate will further enhance scratch resistance by reducing plastic deformation. We tested these hypotheses by applying a hard DLC coating to medical-grade cobalt chromium alloy (CoCr) and magnesia-stabilized zirconia (Mg-PSZ) femoral heads and performing scratch tests to determine the loads required to cause cohesive and adhesive fracture of the coating. Scratch tracks of DLC-coated and noncoated heads were then scanned by optical profilometry to determine scratch depth, width, and pile-up (raised edges), as measures of susceptibility to scratching. DLC-coated CoCr specimens exhibited cohesive coating fracture as wedge spallation at an average load of 9.74 N, whereas DLC-coated Mg-PSZ exhibited cohesive fracture as arc-tensile cracks and chipping at a significantly higher average load of 41.3 N (p coating fracture, DLC-CoCr delaminated at an average load of 35.2 N, whereas DLC-Mg-PSZ fractured by recovery spallation at a significantly higher average load of 46.8 N (p DLC-CoCr and DLC-Mg-PSZ specimens exhibited significantly shallower scratches and less pile-up than did uncoated specimens (p DLC-Mg-PSZ better resisted plastic deformation, requiring significantly higher loads for cohesive and adhesive coating fracture. These findings supported both of our hypotheses. (c) 2008 Wiley Periodicals, Inc.

  7. The scratch test - Different critical load determination techniques. [adhesive strength of thin hard coatings

    Science.gov (United States)

    Sekler, J.; Hintermann, H. E.; Steinmann, P. A.

    1988-01-01

    Different critical load determination techniques such as microscopy, acoustic emission, normal, tangential, and lateral forces used for scratch test evaluation of complex or multilayer coatings are investigated. The applicability of the scratch test to newly developed coating techniques, systems, and applications is discussed. Among the methods based on the use of a physical measurement, acoustic emission detection is the most effective. The dynamics ratio between the signals below and above the critical load for the acoustic emission (much greater than 100) is well above that obtained with the normal, tangential, and lateral forces. The present commercial instruments are limited in load application performance. A scratch tester able to apply accurate loads as low as 0.01 N would probably overcome most of the actual limitations and would be expected to extend the scratch testing technique to different application fields such as optics and microelectronics.

  8. Effect of a hard coat layer on buckle delamination of thin ITO layers on a compliant elasto-plastic substrate: an experimental–numerical approach

    NARCIS (Netherlands)

    Sluis, van der O.; Abdallah, Amir; Bouten, P.C.P.; Timmermans, P.H.M.; Toonder, den J.M.J.; With, de G.

    2011-01-01

    Layer buckling and delamination is a common interfacial failure phenomenon in thin film multi-layer structures that are used in flexible display applications. Typically, the substrate is coated on both sides with a hybrid coating, calleda hard coat (HC), which acts as a gas barrier and also

  9. Evaluation of variables which affect the hardness of nickel plate deposited from watts-type baths

    International Nuclear Information System (INIS)

    Petit, G.S.; Wright, R.R.; Neff, W.A.

    1976-01-01

    In the course of the Cascade Improvement Program, many component equipment parts will be electroplated with nickel for corrosion protection. The maximum hardness which will be acceptable in the electroplated deposit is specified in Union Carbide's Job Specification JS-1396, Revision 3, entitled Electroplated Nickel Coatings on Steel Parts. The hardness specification is intended primarily as a control over both organic and inorganic impurities in the deposit. This report covers a study evaluating several of the numerous controllable variables which influence the hardness of the nickel plate deposited from a Watts-type bath. The variables tested were: 1) bath composition, 2) pH, 3) current density, 4) anode-cathode area ratio, and 5) bath temperature. Within the tested ranges of the variables studied, the pH and current density had the most influence on the plate hardness. The softest deposit was obtained with a bath pH of 1.5, a current density of 30 to 40 amperes/square foot, and with the anode-cathode area ratio in the range of 3:1 to 1:1

  10. Performance evaluation of seal coat materials and designs.

    Science.gov (United States)

    2011-01-01

    "This project presents an evaluation of seal coat materials and design method. The primary objectives of this research are 1) to evaluate seal coat performance : from various combinations of aggregates and emulsions in terms of aggregate loss; 2) to ...

  11. Relationship Between Crystalline Structure and Hardness of Ti-Si-N-O Coatings Fabricated by dc Sputtering

    Science.gov (United States)

    García-González, Leandro; Hernández-Torres, Julián; Mendoza-Barrera, Claudia; Meléndez-Lira, Miguel; García-Ramírez, Pedro J.; Martínez-Castillo, Jaime; Sauceda, Ángel; Herrera-May, Agustin L.; Muñoz Saldaña, Juan; Espinoza-Beltrán, Francisco J.

    2008-08-01

    Ti-Si-N-O coatings were deposited on AISI D2 tool steel and silicon substrates by dc reactive magnetron co-sputtering using a target of Ti-Si with a constant area ratio of 0.2. The substrate temperature was 400 °C and reactive atmosphere of nitrogen and argon. For all samples, argon flow was maintained constant at 25 sccm, while the flow of the nitrogen was varied to analyze the structural changes related to chemical composition and resistivity. According to results obtained by x-ray diffraction and stoichiometry calculations by x-ray energy dispersive spectroscopy the Ti-Si-N-O coatings contain two solid solutions. The higher crystalline part corresponds to titanium oxynitrure. Hardness tests on the coatings were carried out using the indentation work model and the hardness value was determined. Finally, the values of hardness were corroborated by nanoindentation test, and values of Young’s modulus and elastic recovery were discussed. We concluded that F2TSN sample ( F Ar = 25 sccm, F N = 5 sccm, P = 200 W, and P W = 8.9 × 10-3 mbar) presented the greatest hardness and the lowest resistivity values, due to its preferential crystalline orientation.

  12. Comparative of the Tribological Performance of Hydraulic Cylinders Coated by the Process of Thermal Spray HVOF and Hard Chrome Plating

    Directory of Open Access Journals (Sweden)

    R.M. Castro

    2014-03-01

    Full Text Available Due to the necessity of obtaining a surface that is resistant to wear and oxidation, hydraulic cylinders are typically coated with hard chrome through the process of electroplating process. However, this type of coating shows an increase of the area to support sealing elements, which interferes directly in the lubrication of the rod, causing damage to the seal components and bringing oil leakage. Another disadvantage in using the electroplated hard chromium process is the presence of high level hexavalent chromium Cr+6 which is not only carcinogenic, but also extremely contaminating to the environment. Currently, the alternative process of high-speed thermal spraying (HVOF - High Velocity Oxy-Fuel, uses composite materials (metal-ceramic possessing low wear rates. Research has shown that some mechanical properties are changed positively with the thermal spray process in industrial applications. It is evident that a coating based on WC has upper characteristics as: wear resistance, low friction coefficient, with respect to hard chrome coatings. These characteristics were analyzed by optical microscopy, roughness measurements and wear test.

  13. Fabrication of nitrogen-containing diamond-like carbon film by filtered arc deposition as conductive hard-coating film

    Science.gov (United States)

    Iijima, Yushi; Harigai, Toru; Isono, Ryo; Imai, Takahiro; Suda, Yoshiyuki; Takikawa, Hirofumi; Kamiya, Masao; Taki, Makoto; Hasegawa, Yushi; Tsuji, Nobuhiro; Kaneko, Satoru; Kunitsugu, Shinsuke; Habuchi, Hitoe; Kiyohara, Shuji; Ito, Mikio; Yick, Sam; Bendavid, Avi; Martin, Phil

    2018-01-01

    Diamond-like carbon (DLC) films, which are amorphous carbon films, have been used as hard-coating films for protecting the surface of mechanical parts. Nitrogen-containing DLC (N-DLC) films are expected as conductive hard-coating materials. N-DLC films are expected in applications such as protective films for contact pins, which are used in the electrical check process of integrated circuit chips. In this study, N-DLC films are prepared using the T-shaped filtered arc deposition (T-FAD) method, and film properties are investigated. Film hardness and film density decreased when the N content increased in the films because the number of graphite structures in the DLC film increased as the N content increased. These trends are similar to the results of a previous study. The electrical resistivity of N-DLC films changed from 0.26 to 8.8 Ω cm with a change in the nanoindentation hardness from 17 to 27 GPa. The N-DLC films fabricated by the T-FAD method showed high mechanical hardness and low electrical resistivity.

  14. Investigation of Plasma Spray Coatings as an Alternative to Hard Chrome Plating on Internal Surfaces

    Science.gov (United States)

    2006-06-20

    involved in plating and grinding of plated parts. The study estimated that at a typical Naval base the one-time cost of a PEL of 0.5 μgm-3 would be...using automatic control. A wide variety of metals and some cermets can be used as the coating material. As well as evaluating different ESD overlay...to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT

  15. Tribological behavior at elevated temperature of multilayer TiCN/TiC/TiN hard coatings produced by chemical vapor deposition

    International Nuclear Information System (INIS)

    Bao Mingdong; Xu Xuebo; Zhang Haijun; Liu Xiaoping; Tian Linhai; Zeng Zhaoxin; Song Yubin

    2011-01-01

    Multilayer hard coatings of TiCN/TiC/TiN on high speed steel substrates were deposited using a chemical vapor deposition system. Evaluations of microstructure, wear morphology of coatings were characterized by scanning electron microscopy, and optical microscopy. Friction coefficient and wear rates of coatings were investigated using ball-on-disk tester sliding against a WC ball at a constant load of 20 N. Tribological behavior of the coatings at room and elevated temperature were discussed. Different changing tendency of friction coefficient were observed from ball-on-disc experiments. Results showed that the friction coefficient of coatings increased gradually to a highest value, then to a relatively constant value at room temperature dry sliding wear. The friction coefficient exhibited a reverse variation tendency at temperature of 550 °C. It got a higher value at the first sliding friction cycles. Then the value of friction coefficient decreased, suffered irregular oscillations and kept a relatively lower value with increasing sliding time. Reasons of the variation of friction coefficient with sliding time and wear mechanism were analyzed and discussed at room and elevated temperatures, respectively.

  16. Hard carbon coated nano-Si/graphite composite as a high performance anode for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Sookyung; Li, Xiaolin; Zheng, Jianming; Yan, Pengfei; Cao, Ruiguo; Jung, Hee Joon; Wang, Chong M.; Liu, Jun; Zhang, Jiguang

    2016-08-27

    With the ever increasing demands on Li-ion batteries with higher energy densities, alternative anode with higher reversible capacity is required to replace the conventional graphite anode. Here, we demonstrate a cost-effective hydrothermal-carbonization approach to prepare the hard carbon coated nano-Si/graphite (HC-nSi/G) composite as a high performance anode for Li-ion batteries. In this hierarchical structured composite, the hard carbon coating layer not only provides an efficient pathway for electron transfer, but also alleviates the volume variation of silicon during charge/discharge processes. The HC-nSi/G composite electrode shows excellent electrochemical performances including a high specific capacity of 878.6 mAh g-1 based on the total weight of composite, good rate performance and a decent cycling stability, which is promising for practical applications.

  17. Studies of the process of an unsteady formation of hard nitride coatings in an arc plasma flow

    International Nuclear Information System (INIS)

    Zake, M.

    1996-01-01

    The kinetic studies of an unsteady formation of hard ZrN and TiN coatings on the surface of metallic (Zr, Ti) samples in an Ar-N plasma flow are carried out. The obtained result is that at the initial stage of an unsteady heating of titanium samples nitrogen atoms penetrate into metal lattice and form interstitial compounds of hard nitrogen solutions in α-phase of Ti. This process is followed by a growth of thin surface layers of titanium nitrides with subsequent changes of surface radiance of exposed samples. Unsteady formation of ZrN is a similar two-stage process which includes the ZrN film growth and formation of a α-hard solution with subsequent changes of total normal emissivity of the surface. (author). 1 ref., 1 fig

  18. Evaluation of High Temperature Particle Erosion Resistance of Vanadium-Boride Coating

    International Nuclear Information System (INIS)

    Lee, E. Y.; Kim, J. H.; Jeong, S. I.; Lee, S. H.; Eum, G. W.

    2015-01-01

    The components in ultra super critical (USC) steam turbine, which is under development for high efficient power generation, are encountering harsher solid particle erosion by iron oxide scales than ones in the existing steam turbines. Therefore, the currently used boride coating will not be able to hold effective protection from particle erosion in USC system and should be replaced by new particle erosion resistant coatings. One of the best protective coatings developed for USC steam turbine parts was found to be vanadium-boride (V-boride) coating which has a hardness of about 3000 HV, much higher than that of boride, 1600∼2000 HV. In order to evaluate particle erosion resistance of the various coatings such as V-boride, boride and Cr-carbide coatings at high temperature, particle erosion test equipment were designed and manufactured. In addition, erosion particle velocity was simulated using FLUENT software based on semi-implicity method for pressure linked equations revised (SIMPLER). Based on experimental results of this work, the vanadium-boride coating was found to be superior to others and to be a candidate coating to replace the boride coating

  19. Evaluation of High Temperature Particle Erosion Resistance of Vanadium-Boride Coating

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E. Y.; Kim, J. H.; Jeong, S. I. [Andong National University, Andong (Korea, Republic of); Lee, S. H.; Eum, G. W. [Corporate R and D Institute Doosan Heavy Industries and Construction Co., Changwon (Korea, Republic of)

    2015-04-15

    The components in ultra super critical (USC) steam turbine, which is under development for high efficient power generation, are encountering harsher solid particle erosion by iron oxide scales than ones in the existing steam turbines. Therefore, the currently used boride coating will not be able to hold effective protection from particle erosion in USC system and should be replaced by new particle erosion resistant coatings. One of the best protective coatings developed for USC steam turbine parts was found to be vanadium-boride (V-boride) coating which has a hardness of about 3000 HV, much higher than that of boride, 1600∼2000 HV. In order to evaluate particle erosion resistance of the various coatings such as V-boride, boride and Cr-carbide coatings at high temperature, particle erosion test equipment were designed and manufactured. In addition, erosion particle velocity was simulated using FLUENT software based on semi-implicity method for pressure linked equations revised (SIMPLER). Based on experimental results of this work, the vanadium-boride coating was found to be superior to others and to be a candidate coating to replace the boride coating.

  20. On the influence of internal interfaces and properties of multiphase hard material coatings

    International Nuclear Information System (INIS)

    Hilz, G.

    1992-04-01

    In the system TiC-TiB 2 -B 4 C-SiC coatings with different amounts of phase boundaries were prepared by magnetron sputtering: multilayer coatings with 10, 100 and 1000 individual layers and a total thickness of 5 μm as well as single layer multiphase coatings deposited from multiphase targets on heated and unheated substrates. To know the influence of internal interfaces in those coatings, structure and properties of the corresponding single phase coatings were studied also. TEM examinations of cross-section samples showed that B 4 C and SiC coatings are amorphous whereas TiC and TiB 2 coatings are crystalline with a texture which depends on deposition parameters and is developed with growing thickness of the coating. Therefore the texture of TiC and TiB 2 layers in multilayer coatings depends on the thickness of the individual layer. While the texture of single layers in multilayer SiC-TiC, SiC-TiB 2 , B 4 C-TiB 2 , and B 4 C-SiC coatings corresponds to the structure of single phase coatings of the same thickness, in TiC-TiB 2 coatings the texture of the individual layers is also influenced by the texture of the previous layer. The occurence of mixing zones between the layers depends on the materials, but also on the crystallinity of the previous layer. (orig.(MM) [de

  1. Electroless Ni-P/Ni-B duplex coatings: preparation and evaluation of microhardness, wear and corrosion resistance

    International Nuclear Information System (INIS)

    Narayanan, T.S.N. Sankara; Krishnaveni, K.; Seshadri, S.K.

    2003-01-01

    The present work deals with the formation of Ni-P/Ni-B duplex coatings by electroless plating process and evaluation of their hardness, wear resistance and corrosion resistance. The Ni-P/Ni-B duplex coatings were prepared using dual baths (acidic hypophosphite- and alkaline borohydride-reduced electroless nickel baths) with both Ni-P and Ni-B as inner layers and with varying single layer thickness. Scanning electron microscopy (SEM) was used to assess the duplex interface. The microhardness, wear resistance and corrosion resistance of electroless nickel duplex coatings were compared with electroless Ni-P and Ni-B coatings of similar thickness. The study reveals that the Ni-P and Ni-B coatings are amorphous in their as-plated condition and upon heat-treatment at 450 deg. C for 1 h, both Ni-P and Ni-B coatings crystallize and produce nickel, nickel phosphide and nickel borides in the respective coatings. All the three phases are formed when Ni-P/Ni-B and Ni-B/Ni-P duplex coatings are heat-treated at 450 deg. C for 1 h. The duplex coatings are uniform and the compatibility between the layers is good. The microhardness, wear resistance and corrosion resistance of the duplex coating is higher than Ni-P and Ni-B coatings of similar thickness. Among the two types of duplex coatings studied, hardness and wear resistance is higher for coatings having Ni-B coating as the outer layer whereas better corrosion resistance is offered by coatings having Ni-P coating as the outer layer

  2. Effectiveness of solid lubricant coatings for friction in hard vacuum (10-9 tor)

    Science.gov (United States)

    Verkin, B. I.; Lyubraskiy, I. M.; Udovenko, V. F.; Sentyurikhina, L. N.

    1974-01-01

    A study was made of the efficiency of solid lubricating coatings, based on MoS2 with various binders, during friction and under highvacuum conditions. Mass spectrometry was used for an analysis of the composition of the gas evolved from the coatings in the friction process. It is shown that the vacuum level, loading, and sliding velocity influence coating effectiveness. In the friction process the solid lubricant coatings yield characteristic decay products associated with the chemical nature of the binders. The mechanism of coating breakdown during friction is associated with the binder breakdown mechanism.

  3. Tool life of the edges coated with the c-BN+h-BN coatings with different structures during hard machinable steel machining

    Directory of Open Access Journals (Sweden)

    Kupczyk, M.

    2005-12-01

    Full Text Available In the presented paper the experimental results concerning the functional quality (durability during steel machining of thin, superhard coatings produced on the cutting edges are described. Differences among mentioned properties of coatings mainly result from a coating structure. But the structure of coatings results from deposition parameters Superhard boron nitride coatings were deposited on insert cutting edges made of cemented carbides by the pulse-plasma method applying different values of the discharge voltage. The comparative investigations of mentioned coatings have been concerned of tool life of edges during hard machinable material machining (nitriding steel hardened in oil. In these investigations for the purpose of additional increase of coatings adhesion to substrates an interfacial layers were applied.

    En este trabajo se describen los resultados experimentales referentes a la calidad funcional (durabilidad durante el mecanizado del acero de recubrimientos delgados, de elevada dureza del filo de corte. Las diferencias en las propiedades de los recubrimientos se deben, principalmente, a la estructura del recubrimiento. No obstante, la estructura del recubrimiento está relacionada con los parámetros de la deposición. Recubrimientos de nitruro de boro de elevada dureza se depositaron sobre filos de corte insertados, fabricados con carburos cementados mediante el método de pulsos de plasma aplicando diferentes valores de voltaje de descarga. Las investigaciones comparativas de los mencionados recubrimientos han relacionado la vida del filo de la herramienta durante el mecanizado del material (acero nitrurado endurecido en aceite. En estas investigaciones se aplicaron capas interfaciales para aumentar la adherencia del recubrimiento.

  4. Determination of the fatigue behaviour of thin hard coatings using the impact test and a FEM simulation

    Energy Technology Data Exchange (ETDEWEB)

    Bouzakis, K.D. [Aristoteles Univ., Thessaloniki (Greece). Dept. of Mech. Eng.; Vidakis, N. [Aristoteles Univ., Thessaloniki (Greece). Dept. of Mech. Eng.; Leyendecker, T. [CemeCon, 52068 Aachen (Germany); Lemmer, O. [CemeCon, 52068 Aachen (Germany); Fuss, H.G. [CemeCon, 52068 Aachen (Germany); Erkens, G. [CemeCon, 52068 Aachen (Germany)

    1996-12-15

    The impact test, in combination with a finite element method (FEM) simulation, is used to determine stress values that characterise the fatigue behaviour of thin hard coatings, such as TiAlN, TiAlCN, CrN, MoN, etc. The successive impacts of a cemented carbide ball onto a coated probe induce high contact loads, which can vary in amplitude and cause plastic deformation in the substrate. In the present paper FEM calculations are used in order to determine the critical stress values, which lead to coating fatigue failure. The parametric FEM simulation developed considers elastic behaviour for the coating and elastic plastic behaviour for the substrate. The results of the FEM calculations are correlated to experimental data, as well as to SEM observations of the imprints and to microspectrum analyses within the contact region. Herewith, critical values for various stress components, which are responsible for distinctive fatigue failure modes of the coating-substrate compounds can be obtained. (orig.)

  5. An analysis of formation mechanism and nano-scale hardness of the laser-induced coating on Ni–17Mo–7Cr based superalloy

    International Nuclear Information System (INIS)

    He, Yanming; Yang, Jianguo; Fu, Wei; Wang, Limei; Gao, Zengliang

    2016-01-01

    The Ni–17Mo–7Cr based superalloy was laser surface treated in argon atmosphere to enhance its tribological property. The formation mechanism of the coating was revealed and its mechanical properties were characterized. The microstructure and phase identification in the coating were investigated by scanning electron microscope, transmission electron microscope and X-ray diffraction techniques. The mechanical properties of the coating, i.e. elastic modulus and hardness, were measured by nanoindentation tests. The SiC particles were used as the coating materials. During the laser treatment, the SiC will first decompose and the decomposition products Si will trigger the formation of MoC carbides in the coating. After complete solidification, the coating consists of the MoC equiaxed dendrites, interdendritic Ni matrix and graphite. Lot of tiny MoC and chromium carbides can also occur in the interdendritic matrix. The elastic modulus and hardness of MoC are characterized to be 394.0 GPa and 22.3 GPa, which are far higher than that of the matrix (E = 246.8 GPa, H = 5.3 GPa). In addition, the volume fraction of hard MoC can reach about 45.3% in the coating. The method reported in this work will provide us a new approach to fabricate the wear-resisting coating. - Highlights: • The SiC will decompose and the released Si atoms can trigger formation of hard MoC. • The coating consists of MoC equiaxed dendrites, interdendritic matrix and graphite. • The elastic modulus and hardness of MoC are measured to be 394.0 GPa and 22.3 GPa. • The volume fraction of hard MoC in the coating can reach approximately 45.3%.

  6. An analysis of formation mechanism and nano-scale hardness of the laser-induced coating on Ni–17Mo–7Cr based superalloy

    Energy Technology Data Exchange (ETDEWEB)

    He, Yanming [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou, 310014 (China); Yang, Jianguo, E-mail: yangjianguo@hit.edu.cn [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou, 310014 (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, 150001 (China); Fu, Wei [Shanghai Baosteel Industry Technological Service Co., Ltd., Shanghai, 201900 (China); Wang, Limei; Gao, Zengliang [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou, 310014 (China)

    2016-07-15

    The Ni–17Mo–7Cr based superalloy was laser surface treated in argon atmosphere to enhance its tribological property. The formation mechanism of the coating was revealed and its mechanical properties were characterized. The microstructure and phase identification in the coating were investigated by scanning electron microscope, transmission electron microscope and X-ray diffraction techniques. The mechanical properties of the coating, i.e. elastic modulus and hardness, were measured by nanoindentation tests. The SiC particles were used as the coating materials. During the laser treatment, the SiC will first decompose and the decomposition products Si will trigger the formation of MoC carbides in the coating. After complete solidification, the coating consists of the MoC equiaxed dendrites, interdendritic Ni matrix and graphite. Lot of tiny MoC and chromium carbides can also occur in the interdendritic matrix. The elastic modulus and hardness of MoC are characterized to be 394.0 GPa and 22.3 GPa, which are far higher than that of the matrix (E = 246.8 GPa, H = 5.3 GPa). In addition, the volume fraction of hard MoC can reach about 45.3% in the coating. The method reported in this work will provide us a new approach to fabricate the wear-resisting coating. - Highlights: • The SiC will decompose and the released Si atoms can trigger formation of hard MoC. • The coating consists of MoC equiaxed dendrites, interdendritic matrix and graphite. • The elastic modulus and hardness of MoC are measured to be 394.0 GPa and 22.3 GPa. • The volume fraction of hard MoC in the coating can reach approximately 45.3%.

  7. Surface coatings of mixed hard alloy powder metals sintered-on in vacuo

    International Nuclear Information System (INIS)

    Knotek, O.; Reimann, H.

    1980-01-01

    No technological difficulties are to be encountered in the processing of pseudo hard alloys in the form of powder compounds of conventional nickel base hard alloys with carbides. There is a great alloy influence on the resulting structures of the surface layers. Under some processing conditions the tungsten carbide is completely dissolved from molten matrix alloy. Hard phases on chromium carbide basis resulted upon cooling. Induced chromium carbide Cr 3 C 2 retains its structure while absorbing large amounts of iron into its grid. It can be concluded that not only alloying properties, but also eminently structural criterions are decisive for the stability of the applied supplementary hard phases. (orig.) [de

  8. Comparison of high temperature wear behaviour of plasma sprayed WC–Co coated and hard chromium plated AISI 304 austenitic stainless steel

    International Nuclear Information System (INIS)

    Balamurugan, G.M.; Duraiselvam, Muthukannan; Anandakrishnan, V.

    2012-01-01

    Highlights: ► WC–12wt.%Co powders were deposited to a thickness of 300 μm on to steel substrates. ► The micro hardness of the above coatings was lower than that of chromium plating. ► Wear resistance of chromium coating was increased up to five times of AISI 304 austenitic stainless steel. ► Wear resistance of chromium coat higher than plasma coat at different temperatures. -- Abstract: The wear behaviour of plasma sprayed coating and hard chrome plating on AISI 304 austenitic stainless steel substrate is experimentally investigated in unlubricated conditions. Experiments were conducted at different temperatures (room temp, 100 °C, 200 °C and 300 °C) with 50 N load and 1 m/s sliding velocity. Wear tests were carried out by dry sliding contact of EN-24 medium carbon steel pin as counterpart on a pin-on-disc wear testing machine. In both coatings, specimens were characterised by hardness, microstructure, coating density and sliding wear resistance. Wear studies showed that the hard chromium coating exhibited improved tribological performance than that of the plasma sprayed WC–Co coating. X-ray diffraction analysis (XRD) of the coatings showed that the better wear resistance at high temperature has been attributed to the formation of a protective oxide layer at the surface during sliding. The wear mechanisms were investigated through scanning electron microscopy (SEM) and XRD. It was observed that the chromium coating provided higher hardness, good adhesion with the substrate and nearly five times the wear resistance than that obtained by uncoated AISI 304 austenitic stainless steel.

  9. Characterization and analyses on micro-hardness, residual stress and microstructure in laser cladding coating of 316L stainless steel subjected to massive LSP treatment

    Energy Technology Data Exchange (ETDEWEB)

    Luo, K.Y.; Jing, X.; Sheng, J. [School of Mechanical Engineering, Jiangsu University, Zhenjiang, 212013 (China); Sun, G.F. [School of Mechanical Engineering, Southeast University, Nanjing, 211189 (China); Yan, Z. [School of Mechanical Engineering, Jiangsu University, Zhenjiang, 212013 (China); Lu, J.Z., E-mail: jzlu@ujs.edu.cn [School of Mechanical Engineering, Jiangsu University, Zhenjiang, 212013 (China)

    2016-07-15

    The effects of massive laser shock peening (LSP) treatment on micro-hardness, residual stress and microstructure in four different zones of laser cladding coating was investigated. Furthermore, micro-hardness curves and residual stress distributions with and without massive LSP treatment were presented and compared, and typical microstructure in different zones of both coatings were characterized by transmission electron microscope (TEM) and cross-sectional optical microscope (OM) observations. Results and analyses showed that massive LSP treatment had an important influence on micro-hardness and residual stress of the cladding coating. Special attempt was made to the effects of massive LSP treatment on microstructure in three zones of the cladding coating. In addition, the underlying mechanism of massive LSP treatment on microstructure and mechanical properties of the cladding coating was revealed clearly. - Highlights: • Micro-hardness and residual stress curves of both coatings were presented and compared. • Typical microstructure in different zones of both coatings were characterized and analyzed. • LSP causes increased micro-activities, and induces plastic deformation layer in three zones. • Underlying mechanism of LSP on mechanical properties of cladding coating was revealed.

  10. Evaluation of the adhesion strength of diamond films brazed on K-10 type hard metal

    Directory of Open Access Journals (Sweden)

    Santos Sérgio Ivan dos

    2004-01-01

    Full Text Available The coating of cutting tools with diamond films considerably increases the tool performance due to the combination of the unique tribological properties of diamond with the bulk properties of the substrate (toughness. The tool performance, however, is strongly related to the adhesion strength between the film and the substrate. In this work our main goal was to propose and to test a procedure, based on a tensile strength test, to evaluate the adhesion strength of a diamond wafer brazed on a hard metal substrate, taking into account the effect of the brazing temperature and time. The temperature range studied was from 800 to 980 °C and the brazing time ranged from 3 to 40 min. The obtained results could be used to optimize the costs and time required to the production of high performance cutting tools with brazed diamond wafers.

  11. Experimental investigation of various surface integrity aspects in hard turning of AISI 4340 alloy steel with coated and uncoated cermet

    Science.gov (United States)

    Das, Anshuman; Patel, S. K.; Sateesh Kumar, Ch.; Biswal, B. B.

    2018-03-01

    The newer technological developments are exerting immense pressure on domain of production. These fabrication industries are busy finding solutions to reduce the costs of cutting materials, enhance the machined parts quality and testing different materials, which can be made versatile for cutting materials, which are difficult for machining. High-speed machining has been the domain of paramount importance for mechanical engineering. In this study, the variation of surface integrity parameters of hardened AISI 4340 alloy steel was analyzed. The surface integrity parameters like surface roughness, micro hardness, machined surface morphology and white layer of hardened AISI 4340 alloy steel were compared using coated and uncoated cermet inserts under dry cutting condition. From the results, it was deduced that coated insert outperformed uncoated one in terms of different surface integrity characteristics.

  12. Enhanced electrical conductivity and hardness of silver-nickel composites by silver-coated multi-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Lee, Dongmok; Sim, Jeonghyun; Baik, Seunghyun; Kim, Wonyoung; Moon, Chuldong; Cho, Wookdong

    2015-01-01

    We investigated electrical conductivity and Vickers hardness of Ag- and Ni-based composites prepared by powder metallurgy involving spark plasma sintering. The starting composition was Ag:Ni = 61:39 vol%, which provided an electrical conductivity of 3.30 × 10"5 S cm"−"1 and a hardness of 1.27 GPa. The addition of bare multi-walled carbon nanotubes (MWNTs, 1.45 vol%) increased hardness (1.31 GPa) but decreased electrical conductivity (2.99 × 10"5 S cm"−"1) and carrier mobility (11 cm"2 V"−"1 s"−"1) due to the formation of Ni_3C in the interface between the MWNTs and Ni during spark plasma sintering. The formation of Ni_3C was prevented by coating the surface of the nanotubes with Ag (nAgMWNTs), concomitantly increasing electrical conductivity (3.43 × 10"5 S cm"−"1) and hardness (1.37 GPa) of the sintered specimen (Ag:Ni:nAgMWNTs = 59.55:39:1.45 vol%). The electrical contact switching time (133 357) was also increased by 30%, demonstrating excellent feasibility as electrical contact materials for electric power industries. (paper)

  13. Progress in Tribological Properties of Nano-Composite Hard Coatings under Water Lubrication

    Directory of Open Access Journals (Sweden)

    Qianzhi Wang

    2017-02-01

    Full Text Available The tribological properties, under water-lubricated conditions, of three major nano-composite coatings, i.e., diamond-like carbon (DLC or a-C, amorphous carbon nitride (a-CNx and transition metallic nitride-based (TiN-based, CrN-based, coatings are reviewed. The influences of microstructure (composition and architecture and test conditions (counterparts and friction parameters on their friction and wear behavior under water lubrication are systematically elucidated. In general, DLC and a-CNx coatings exhibit superior tribological performance under water lubrication due to the formation of the hydrophilic group and the lubricating layer with low shear strength, respectively. In contrast, TiN-based and CrN-based coatings present relatively poor tribological performance in pure water, but are expected to present promising applications in sea water because of their good corrosion resistance. No matter what kind of coatings, an appropriate selection of counterpart materials would make their water-lubricated tribological properties more prominent. Currently, Si-based materials are deemed as beneficial counterparts under water lubrication due to the formation of silica gel originating from the hydration of Si. In the meantime, the tribological properties of nano-composite coatings in water could be enhanced at appropriate normal load and sliding velocity due to mixed or hydrodynamic lubrication. At the end of this article, the main research that is now being developed concerning the development of nano-composite coatings under water lubrication is described synthetically.

  14. Hard Chrome-Coated and Fullerene-Doped Metal Surfaces in Orthopedic Bearings.

    Science.gov (United States)

    Sonntag, Robert; Feige, Katja; Dos Santos, Claudia Beatriz; Kretzer, Jan Philippe

    2017-12-20

    Metal-on-metal bearings for total hip replacements have been introduced as an alternative to polyethylene in young and more active patients. These have, however, been shown to be prone to implant malpositioning and have been limited by some specific design features. In that context, coatings present an option to increase wear resistance by keeping the high fracture strength of the metal substrate. A custom-made electroplating setup was designed for the coating of CoCr substrates using (a) an industrial standard chromium electrolyte; (b) a custom-made hexavalent chromium (Cr 6+ ) electrolyte with a reduced chromium trioxide (CrO₃) content, both without solid additives and (c) with the addition of fullerene (C 60 ) nanoparticles; and (d) a trivalent chromium (Cr 3+ ) electrolyte with C 60 addition. All coatings showed an increase in microhardness compared with the metal substrate. Trivalent coatings were thinner (10 µm) than the hexavalent coatings (23-40 µm) and resulted in increased roughness and crack density. Wear was found to be reduced for the hexavalent chromium coatings by 70-84% compared with the CoCr-CoCr reference bearing while the trivalent chromium coating even increased wear by more than 300%. The addition of fullerenes to the electrolyte did not show any further tribological effect.

  15. Hard Chrome-Coated and Fullerene-Doped Metal Surfaces in Orthopedic Bearings

    Directory of Open Access Journals (Sweden)

    Robert Sonntag

    2017-12-01

    Full Text Available Metal-on-metal bearings for total hip replacements have been introduced as an alternative to polyethylene in young and more active patients. These have, however, been shown to be prone to implant malpositioning and have been limited by some specific design features. In that context, coatings present an option to increase wear resistance by keeping the high fracture strength of the metal substrate. A custom-made electroplating setup was designed for the coating of CoCr substrates using (a an industrial standard chromium electrolyte; (b a custom-made hexavalent chromium (Cr6+ electrolyte with a reduced chromium trioxide (CrO3 content, both without solid additives and (c with the addition of fullerene (C60 nanoparticles; and (d a trivalent chromium (Cr3+ electrolyte with C60 addition. All coatings showed an increase in microhardness compared with the metal substrate. Trivalent coatings were thinner (10 µm than the hexavalent coatings (23–40 µm and resulted in increased roughness and crack density. Wear was found to be reduced for the hexavalent chromium coatings by 70–84% compared with the CoCr–CoCr reference bearing while the trivalent chromium coating even increased wear by more than 300%. The addition of fullerenes to the electrolyte did not show any further tribological effect.

  16. Development and Testing of Abrasion Resistant Hard Coats For Polymer Film Reflectors: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, G.; Gee, R.; DiGrazia, M.

    2010-10-01

    Reflective polymer film technology can significantly reduce the cost of solar reflectors and installed Concentrated Solar Power (CSP) plants by both reduced material cost and lower weight. One challenge of polymer reflectors in the CSP environment pertains to contact cleaning methods typically used with glass mirrors. Such contact cleaning methods can scratch the surface of polymer reflectors and thereby reduce specular reflectance. ReflecTech, Inc. (a subsidiary of SkyFuel, Inc.) and the National Renewable Energy Laboratory (NREL) initiated a cooperative research and development agreement (CRADA) to devise and develop an abrasion resistant coating (ARC) suitable for deposition onto polymer based mirror film. A number of candidate ARC products were identified as candidate formulations. Industrial collaborators prepared samples having their ARCs deposited onto ReflecTech Mirror Film pre-laminated to aluminum sheet substrates. Samples were provided for evaluation and subjected to baseline (unweathered) and accelerated exposure conditions and subsequently characterized for abrasion resistance and adhesion. An advanced ARC product has been identified that exhibits outstanding initial abrasion resistance and adhesion to ReflecTech Mirror Film. These properties were also retained after exposure to the various accelerated stress conditions. This material has been successfully manufactured as a 1.5 m wide roll-to-roll construction in a production environment.

  17. Hard chrome-coated and fullerene-doped metal surfaces in orthopedic bearings

    OpenAIRE

    Sonntag, Robert; Feige, Katja; Santos, Claudia Beatriz dos; Kretzer, Jan Philippe

    2017-01-01

    Metal-on-metal bearings for total hip replacements have been introduced as an alternative to polyethylene in young and more active patients. These have, however, been shown to be prone to implant malpositioning and have been limited by some specific design features. In that context, coatings present an option to increase wear resistance by keeping the high fracture strength of the metal substrate. A custom-made electroplating setup was designed for the coating of CoCr substrates using (a) an ...

  18. Evaluating microhardness of plasma sprayed Al2O3 coatings using Vickers indentation technique

    International Nuclear Information System (INIS)

    Yin Zhijian; Tao Shunyan; Zhou Xiaming; Ding Chuanxian

    2007-01-01

    In this work, the microhardness of plasma sprayed Al 2 O 3 coatings was evaluated using the Vickers indentation technique, and the effects of measurement direction, location and applied loads were investigated. The measured data sets were then statistically analysed employing the Weibull distribution to evaluate their variability within the coatings. It was found that the Vickers hardness (VHN) increases with decreasing applied indenter load, which can be explained in terms of Kick's law and the Meyer index k of 1.93, as well as relating to the microstructural characteristics of plasma sprayed coatings and the elastic recovery taking place during indentation. In addition, VHN, measured on the cross section of coatings, was obviously higher than that on its top surface. The obtained Weibull modulus and variation coefficient indicate that the VHN was less variable when measured at a higher applied load and on the cross section of coating. The obvious dependence of the VHN on the specific indentation location within through-thickness direction was also realized. These phenomena described above in this work were related to the special microstructure and high anisotropic behaviour of plasma sprayed coatings

  19. The Role of Diffusion Media in Nitriding Process on Surface Layers Characteristics of AISI 4140 with and without Hard Chrome Coatings

    Directory of Open Access Journals (Sweden)

    K.A. Widi

    2016-09-01

    Full Text Available The surface layer characteristics of the AISI 4140 tool steel treated by nitriding gas before and after hard chrome plating utilizing pure nitrogen diffusion media (fluidized bed reactor and the without gas (muffle reactor has been studied experimentally. The result shows that nitriding substrate with hard chrome layers has nitrogen atoms concentration almost twice greater than that without hard chrome layers. After being given a hard chrome plating, nitriding on AISI 4140 steel generally has a nitrogen concentration of up to 4 times more than the substrate without hard chrome coating. Almost the entire specimen showed the highest concentration of N atoms in the area below the surface (hardening depth of 200 to 450 µm. N atoms diffusion depth profile has a correlation with hardening depth profile, especially on the specimens layered with hard chromium. The substrate without hard chrome plating tends to have higher surface hardness than the sub-surface. The results show that the effectiveness and efficiency of the gas nitriding diffusion process can be produced without the use of gas in the muffle reactor but the specimens must be hard chromium coated first. This phenomenon can be explained by the role of the passive layer formation that works as a barrier to keeps the spreading of N atoms concentrated in sub-surface areas.

  20. Friction and wear of stainless steel, titanium and aluminium with various surface treatments, ion implantation and overlay hard coatings

    International Nuclear Information System (INIS)

    Bunshah, R.F.

    1979-01-01

    This paper deals with the evaluation of the wear properties of 304 stainless steel, commercial grade titanium and commercial grade aluminium without and with different surface treatments, i.e., ion implantation of boron and nitrogen, and overlay coating of superhard materials, titanium carbide and nitride by the Biased Activated Reactive Evaporation (BARE) process. Wear properties were evaluated in adhesive, erosive and abrasive modes of wear. In the case of adhesive wear, ion implantation resulted in an improved wear behaviour in lubricated conditions but had no beneficial effect in dry wear conditions. Overlay coatings on the other hand resulted in improved wear behaviour for both the dry and lubricating conditions. In the case of erosive wear with SiC particles at high velocities, overlay coatings showed higher erosion rates (typical of brittle materials in normal impingement) whereas ion implanted materials behaved similarly as untreated materials; i.e., a lower wear rate than the specimens with overlay coatings. In the case of abrasive wear, it was again observed that the wear rates of overlay coatings is far lower than the wear rates of untreated or ion implanted materials. (author)

  1. Experimental evaluation of optimization method for developing ultraviolet barrier coatings

    Science.gov (United States)

    Gonome, Hiroki; Okajima, Junnosuke; Komiya, Atsuki; Maruyama, Shigenao

    2014-01-01

    Ultraviolet (UV) barrier coatings can be used to protect many industrial products from UV attack. This study introduces a method of optimizing UV barrier coatings using pigment particles. The radiative properties of the pigment particles were evaluated theoretically, and the optimum particle size was decided from the absorption efficiency and the back-scattering efficiency. UV barrier coatings were prepared with zinc oxide (ZnO) and titanium dioxide (TiO2). The transmittance of the UV barrier coating was calculated theoretically. The radiative transfer in the UV barrier coating was modeled using the radiation element method by ray emission model (REM2). In order to validate the calculated results, the transmittances of these coatings were measured by a spectrophotometer. A UV barrier coating with a low UV transmittance and high VIS transmittance could be achieved. The calculated transmittance showed a similar spectral tendency with the measured one. The use of appropriate particles with optimum size, coating thickness and volume fraction will result in effective UV barrier coatings. UV barrier coatings can be achieved by the application of optical engineering.

  2. Improvement of deposition efficiency and control of hardness for cold-sprayed coatings using high carbon steel/mild steel mixture powder

    International Nuclear Information System (INIS)

    Ogawa, Kazuhiro; Amao, Satoshi; Yokoyama, Nobuyuki; Ootaki, Kousuke

    2011-01-01

    In this study, in order to make high carbon steel coating by cold spray technique, spray conditions such as carrier gas temperature and pressure etc. were investigated. And also, in order to improve deposition efficiency and control coating hardness of cold-sprayed high carbon steel, high carbon and mild steel mixed powder and its mechanical milled powder were developed and were optimized. By using the cold-spray technique, particle deposition of a high carbon steel was successful. Moreover, by applying mixed and mechanical milled powders, the porosity ratio was decreased and deposition efficiency was improved. Furthermore, using these powders, it is possible to control the hardness value. Especially, when using mechanical milled powder, it is very difficult to identify the interface between the coating and the substrate. The bonding between the coating and the substrate is thus considered to be excellent. (author)

  3. Evaluation of stability for monolayer injection molding tools coating

    DEFF Research Database (Denmark)

    Cech, Jiri; Taboryski, Rafael J.

    2012-01-01

    We tested and characterized molecular coating of Aluminium and Nickel prototype molds and mold inserts for polymer replication via injection molding (IM). X-Ray photoelectron spectroscopy (XPS) data, sessile drop contact angles with multiple fluids, surface energy and roughness data have been...... collected and used to predict coating lifetimes. Samples have been characterized immediately after coating, after 500+ IM cycles to test durability and after 7 months to test temporal stability. Sessile drop contact angle was measured for multiple fluids, namely water, di-iodomethane and benzylacohol....... Detectable coating presence was indicated by an increased angle on all post IM samples. To conclude, we present mold coating evaluation method, which is well suited for ultrathin, controlable, covalently bonded coating, that is reasonably durable, affordable, scalable to production, detectable on surface...

  4. A field evaluation of coated urea with biodegradable materials and ...

    African Journals Online (AJOL)

    Urease inhibitor and biodegradable polymer coatings are two most suitable startegies to increase urea fertilizer efficiency. Coating of urea with selected inhibitors can increase the crop production by slowing down the hydrolysis process of urea in the soil. For this purpose, a field experiment was conducted to evaluate the ...

  5. Investigation of Plasma Spray Coatings as an Alternative to Hard Chrome Plating on Internal Surfaces

    Science.gov (United States)

    2006-09-14

    obtain a full curve, with runout defined as 107 cycles. Maximum stresses were 220ksi, which is just below yield, and above the maximum that would be...4.7. Abrasive wear 4.7.1. Test methods Abrasive wear was measured using the ASTM G-65 method of a rubber wheel with dry sand rubbing against the...coated with WC self fluxing material (NI-988) and used to test different finishing methods. Silicon carbide, aluminum oxide and diamond grinding wheels

  6. A review of producing hard coatings by means of duplex treatments using an electroplated coating–thermochemical treatment combination

    Directory of Open Access Journals (Sweden)

    Héctor Cifuentes Aya

    2011-09-01

    Direct deposition by physical vapour deposition (PVD, used for obtaining chromium nitride films on steel substrates, is limited by high production costs, the low thickness obtained and low resistance to corrosion due to the presence of micro pores. Some studies have combined an electroplated chromium with thermochemical treatments made in a controlled atmosphere or vacuum furnaces or by plasma. This kind of duplex treatment allows compounds such as CrxN, CrxCyN and CrxCy to be obtained from chemical and micro structural transformation of chromium with nitrogen and/or carbon, the sealing of cracks in the coating and increasing the magnitude of properties like hardness and density, improving wear and abrasion and corrosion resistance.

  7. Microindentation hardness evaluation of iridium alloy clad vent set cups

    International Nuclear Information System (INIS)

    Ulrich, G.B.; DeRoos, L.F.; Stinnette, S.E.

    1993-01-01

    An iridium alloy, DOP-26, is used as cladding for 238 PuO 2 fuel in radioisotope heat sources for space power systems. Presently, DOP-26 iridium alloy clad vent sets (CVS) are being manufactured at the Oak Ridge Y-12 Plant for potential use in the National Aeronautics and Space Administration's Cassini mission to Saturn. Wrought/ground/stress relieved blanks are warm formed into CVS cups. These cups are then annealed to recrystallize the material for subsequent fabrication/assembly operations as well as for final use. One of the cup manufacturing certification requirements is to test for Vickers microindentation hardness. New microindentation hardness specification limits, 210 to 310 HV, have been established for a test load of 1000 grams-force (gf). The original specification limits, 250 to 350 HV, were for 200 gf testing. The primary reason for switching to a higher test load was to reduce variability in the test data. The DOP-26 alloy exhibits microindentation hardness load dependence, therefore, new limits were needed for 1000 gf testing. The new limits were established by testing material from 15 CVS cups using 200 gf and 1000 gf loads and then statistically analyzing the data. Additional work using a Knoop indenter and a 10 gf load indicated that the DOP-26 alloy grain boundaries have higher hardnesses than the grain interiors

  8. Microindentation hardness evaluation of iridium alloy clad vent set cups

    International Nuclear Information System (INIS)

    Ulrich, G.B.; DeRoos, L.F.; Stinnette, S.E.

    1992-01-01

    An iridium alloy, DOP-26, is used as cladding for 238 PuO 2 fuel in radioisotope heat sources for space power systems. Presently, DOP-26 iridium alloy clad vent sets (CVS) are being manufactured at the Oak Ridge Y-12 Plant for potential use in the National Aeronautics and Space Administration's Cassini mission to Saturn. Wrought/ground/stress relieved blanks are warm formed into CVS cups. These cups are then annealed to recrystallize the material for subsequent fabrication/assembly operations as well as for final use. One of the cup manufacturing certification requirements is to test for Vickers microindentation hardness. New microindentation hardness specification limits, 210 to 310 HV, have been established for a test load of 1000 grams-force (gf). The original specification limits, 250 to 350 HV, were for 200 gf testing. The primary reason for switching to a higher test load was to reduce variability in the test data. The DOP-26 alloy exhibits microindentation hardness load dependence, therefore, new limits were needed for 1000 gf testing. The new limits were established by testing material from 15 CVS cups using 200 gf and 1000 gf loads and then statistically analyzing the data. Additional work using a Knoop indenter and a 10 gf load indicated that the DOP-26 alloy grain boundaries have higher hardnesses than the grain interiors

  9. Microstructural characterizations and hardness evaluation of d.c. ...

    Indian Academy of Sciences (India)

    Administrator

    The preferred orientations of CrN thin films are strongly influenced ... able oxides were formed on CrAlN coating even at 800°C ... tion, λ the X-ray wavelength, θ the Bragg angle and .... mobility of grain boundaries leads to variations in the.

  10. Tribological behaviour at high temperature of hard CrAlN coatings doped with Y or Zr

    International Nuclear Information System (INIS)

    Sánchez-López, J.C.; Contreras, A.; Domínguez-Meister, S.; García-Luis, A.; Brizuela, M.

    2014-01-01

    The tribological properties of CrAlN, CrAlYN and CrAlZrN coatings deposited by direct current reactive magnetron sputtering are studied by means of pin-on-disc experiments at room temperature, 300, 500 and 650 °C using alumina balls as counterparts. The influence of the metallic composition (Al, Y and Zr) on the friction, wear properties and oxidation resistance is studied by means of scanning electron microscopy, energy dispersive X-ray analysis and Raman analysis of the contact region after the friction tests. The results obtained allow us to classify the tribological behaviour of the CrAl(Y,Zr)N coatings into three groups according to the nature of the dopant and aluminium content. The sliding wear mechanism is characterized by the formation of an overcoat rich in chromium and aluminium oxides whose particular composition is determined by the initial chemical characteristics of the coating and the testing temperature. The fraction of Cr 2 O 3 becomes more significant as the Al content decreases and the temperature increases. The addition of Y, and particularly Zr, favours the preferential formation of Cr 2 O 3 versus CrO 2 leading to a reduction of friction and wear of the counterpart. Conversely, the tribological behaviour of pure CrAlN coatings is characterized by higher friction but lower film wear rates as a result of higher hardness and major presence of aluminium oxides on the coating surface. - Highlights: • Comparative tribological study at high temperature of CrAlN, CrAlYN and CrAlZrN films • Fraction of Cr 2 O 3 raises as the Al content decreases and the temperature increases. • Zr doping favours lower and steady friction coefficient due to higher Cr 2 O 3 formation. • Sliding wear mechanism becomes predominantly abrasive as the Al content increases. • Excellent tribological performance of CrAlN doped with low Y contents (≈ 2 at.%)

  11. Feed rate affecting surface roughness and tool wear in dry hard turning of AISI 4140 steel automotive parts using TiN+AlCrN coated inserts

    Science.gov (United States)

    Paengchit, Phacharadit; Saikaew, Charnnarong

    2018-02-01

    This work aims to investigate the effects of feed rate on surface roughness (Ra) and tool wear (VB) and to obtain the optimal operating condition of the feed rate in dry hard turning of AISI 4140 chromium molybdenum steel for automotive industry applications using TiN+AlCrN coated inserts. AISI 4140 steel bars were employed in order to carry out the dry hard turning experiments by varying the feed rates of 0.06, 0.08 and 0.1 mm/rev based on experimental design technique that can be analyzed by analysis of variance (ANOVA). In addition, the cutting tool inserts were examined after machining experiments by SEM to evaluate the effect of turning operations on tool wear. The results showed that averages Ra and VB were significantly affected by the feed rate at the level of significance of 0.05. Averages Ra and VB values at the feed rate of 0.06 mm/rev were lowest compared to average values at the feed rates of 0.08 and 0.1 mm/rev, based on the main effect plot.

  12. Trackless tack coat materials : a laboratory evaluation performance acceptance.

    Science.gov (United States)

    2012-06-01

    The purpose of this study was to develop, demonstrate, and document laboratory procedures that could be used by the : Virginia Department of Transportation (VDOT) to evaluate non-tracking tack coat materials. The procedures would be used to : qualify...

  13. Weightless Environment Training Facility (WETF) materials coating evaluation, volume 1

    Science.gov (United States)

    1995-01-01

    The Weightless Environment Training Facility Material Coating Evaluation project has included preparing, coating, testing, and evaluating 800 test panels of three differing substrates. Ten selected coating systems were evaluated in six separate exposure environments and subject to three tests for physical properties. Substrate materials were identified, the manner of surface preparation described, and exposure environments defined. Exposure environments included immersion exposure, cyclic exposure, and field exposure. Cyclic exposures, specifically QUV-Weatherometer and the KTA Envirotest were found to be the most agressive of the environments included in the study when all three evaluation criteria are considered. This was found to result primarily from chalking of the coatings under ultraviolet (UV) light exposure. Volumes 2 and 3 hold the 5 appendices to this report.

  14. Haemocompatibility evaluation of DLC- and SiC-coated surfaces

    Directory of Open Access Journals (Sweden)

    Nurdin N.

    2003-06-01

    Full Text Available Diamond-like carbon (DLC and silicon carbide (SiC coatings are attractive because of low friction coefficient, high hardness, chemical inertness and smooth finish, which they provide to biomedical devices. Silicon wafers (Siwaf and silicone rubber (Sirub plates were coated using plasma-enhanced chemical vapour deposition (PE-CVD techniques. This article describes: 1- the characterization of modified surfaces using attenuated total reflection-Fourier transform infrared spectroscopy (ATR/FTIR and contact angle measurements, 2- the results of three in-vitro haemocompatibility assays. Coated surfaces were compared to uncoated materials and various substrates such as polymethylmethacrylate (PMMA, polyethylene (LDPE, polydimethylsiloxane (PDMS and medical steel (MS. Thrombin generation, blood platelet adhesion and complement convertase activity tests revealed the following classification, from the most to the least heamocompatible surface: Sirub/ DLC-Sirub/ DLC-Siwaf/ LDPE/ PDMS/ SiC-Siwaf/ Siwaf/ PMMA/ MS. The DLC coating surfaces delayed the clotting time, tended to inhibit the platelet and complement convertase activation, whereas SiC-coated silicon wafer can be considered as thrombogenic. This study has taken into account three events of the blood activation: coagulation, platelet activation and inflammation. The response to those events is an indicator of the in vitro haemocompatibility of the different surfaces and it allows us to select biomaterials for further in vivo blood contacting investigations.

  15. Comparative study of the interface composition of TiN and TiCN hard coatings on high speed steel substrates obtained by arc discharge

    Energy Technology Data Exchange (ETDEWEB)

    Roman, E. (Lab. de Fisica de Superficies, Inst. de Ciencia de Materiales, CSIC, Madrid (Spain)); Segovia, J.L. de (Lab. de Fisica de Superficies, Inst. de Ciencia de Materiales, CSIC, Madrid (Spain)); Alberdi, A. (TEKNIKER, Asociacion de Investigacion Tecnologica, Eibar (Spain)); Calvo, J. (TEKNIKER, Asociacion de Investigacion Tecnologica, Eibar (Spain)); Laucirica, J. (TEKNIKER, Asociacion de Investigacion Tecnologica, Eibar (Spain))

    1993-05-15

    In this paper the composition of the interface of TiN and TiCN hard coatings deposited onto high speed steel substrates obtained by the arc discharge technique is studied using Auger electron spectroscopy at two different substrate temperatures, 520 K and 720 K. The low temperature (520 K) TiN coating developed an oxygen phase at the interface, producing a weak adherence of 40 N, while the high temperature coatings (720 K) had a less intense oxygen phase, giving a greater adherence to the substrate of 60 N. TiCN coatings at 520 K are characterized by a low oxygen intensity at the interface. However, their adherence of 50 N is lower than the value of 60 N for the high temperature TiN coatings and is independent of the substrate temperature. (orig.)

  16. Evolution of structure and mechanical properties of hard yet fracture resistant W-B-C coatings with varying C/W ratio

    Czech Academy of Sciences Publication Activity Database

    Alishahi, M.; Mirzaei, S.; Souček, P.; Zábranský, L.; Buršíková, V.; Stupavska, M.; Peřina, Vratislav; Balázsi, K.; Czigany, Z.; Vašina, P.

    2018-01-01

    Roč. 340, č. 4 (2018), s. 103-111 ISSN 0257-8972 R&D Projects: GA MŠk LM2015056 Institutional support: RVO:61389005 Keywords : magnetron sputtering * W-B-C * microstructure * hardness * fracture resistance Subject RIV: JK - Corrosion ; Surface Treatment of Materials OBOR OECD: Coating and films Impact factor: 2.589, year: 2016

  17. Comparative Evaluation and Optimization of Film Coating ...

    African Journals Online (AJOL)

    In this study, hydroxypropyl methylcellulose phthalate (HPMCP) and two polymethacrylates, Wangit L30D-55® and Wangit L-100® were investigated for their enteric coating properties using diclofenac sodium tablets as core. Both polymers showed acid protective effect at the weight gain of 6%. Polymethacrylate based ...

  18. A hard X-ray telescope/concentrator design based on graded period multilayer coatings

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Joensen, K. D.; Gorenstein, P.

    1995-01-01

    It is shown that compact designs of multifocus, conical approximations to highly nested Wolter I telescopes, as well as single reflection concentrators, employing realistic graded period W/Si or Ni/C multilayer coatings, allow one to obtain more than 1000 cm2 of on-axis effective area at 40 ke...... that it is smaller than roughly 1 mm. The design can be realized with foils as thin (≤0.4 mm) as used for ASCA and SODART or with closed, slightly thicker (∼1.0 mm) mirror shells as used for JET-X and XMM. The effect of an increase of the inner radius is quantified on the effective area for multilayered mirrors up...

  19. Evaluation of Plasma Spray hydroxy Apatite Coatings on Metallic Materials

    International Nuclear Information System (INIS)

    Take, S.; Mitsul, K.; Kasahara, M.; Sawal, R.; Izawa, S.; Nakayama, M.; Itoi, Y.

    2007-01-01

    Biocompatible Hydroxy apatite (HAp) coatings on metallic substrate by plasma spray techniques have been developed. Long-term credibility of plasma spray HAp coatings has been evaluated in physiological saline by electrochemical measurements. It was found that the corrosion resistance of SUS316L based HAp/Ti combined coatings was excellent even after more than 10 weeks long-term immersion. It was shown that postal heat treatment improved both the crystallinity and corrosion resistance of HAp. By lowering cooling rate during heat treatment process, less cracks produced in HAp coating layer, which lead to higher credibility of HAp during immersion in physiological saline. The ICP results showed that the dissolution level of substrate metallic ions was low and HAp coatings produced in this research can be acceptable as biocompatible materials. Also, the concentration of dissolved ions from HAp coatings with postal heat treatment was lower compared to those from samples without postal heat treatment. The adherence of HAp coatings with Ti substrate and other mechanical properties were also assessed by three-point bending test. The poor adhesion of HAp coating to titanium substrate can be improved by introducing a plasma spray titanium intermediate layer

  20. Evaluation of Degradation of Isothermally Aged Plasma-Sprayed Thermal Barrier Coating

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Jae Mean; Seok, Chang Sung; Kang, Min Sung; Kim, Dae Jin [Sungkyunkwan University, Seoul (Korea, Republic of); Lee, Dong Hoon [HYUNDAI STEEL CO., Incheon (Korea, Republic of); Kim, Mun Young [KPS Gas Turbine Technology Service Center, Seongnam (Korea, Republic of)

    2010-04-15

    The thermal barrier coating of a gas turbine blade was degraded by isothermal heating in a furnace and by varying the exposure time and temperature. Then, a micro-Vickers hardness test was conducted on the cross section of the bond coat and Ni-based superalloy substrate. Further, the thickness of TGO(Thermally Grown Oxide) was measured by using an image analyzer, and the changes in the microstructure and element contents in the coating were analyzed by using an optical microscope and by performing SEM-EDX analysis. No significant change was observed in the Vickers hardness of the bond coat when the coated specimen was degraded at a high temperature: delamination was observed between the top coat and the bond coat when the coating was degraded for 50 h at a temperature 1,151 .deg. C.

  1. Evaluation of a Degradation of Thermal Barrier Coating for Gas Turbine Blade

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae Jin; Lee, Dong Hoon; Koo, Jae Mean; Seok, Chang Sung [Sungkyunkwan Univ., Seoul (Korea, Republic of); Kim, Mun Young; Yang, Sung Ho; Park, Sang Yoel [Korea Power Engineering Company, Inc., Yongin (Korea, Republic of)

    2007-07-01

    Thermal barrier coating system for gas turbine blade were thermally aged by isothermal heating in the furnace varing aging time and temperature. Then, micro Vickers hardness test was done for the cross section of bond coat and Ni-based superalloy substrate. Also, the thickness of TGO was measured by image analyzer and the changes in the microstructure and element distributions in the coating were analyzed by optical microscope and SEM-EDX analysis. No significant changes in the Vickers hardness of the bond coat were observed as the coated specimen was aged at high temperature and delaminations near between top coat and bond coat occurred when the coatings were aged for 50 hr at over 1,151 .deg. C.

  2. Mechanical and Tribological Properties of PVD-Coated Cemented Carbide as Evaluated by a New Multipass Scratch-Testing Method

    Directory of Open Access Journals (Sweden)

    M. Fallqvist

    2012-01-01

    Full Text Available A new test method based on multipass scratch testing has been developed for evaluating the mechanical and tribological properties of thin, hard coatings. The proposed test method uses a pin-on-disc tribometer and during testing a Rockwell C diamond stylus is used as the “pin” and loaded against the rotating coated sample. The influence of normal load on the number of cycles to coating damage is investigated and the resulting coating damage mechanisms are evaluated by posttest scanning electron microscopy. The present study presents the test method by evaluating the performance of Ti0.86Si0.14N, Ti0.34Al0.66N, and (Al0.7Cr0.32O3 coatings deposited by cathodic arc evaporation on cemented carbide inserts. The results show that the test method is quick, simple, and reproducible and can preferably be used to obtain relevant data concerning the fatigue, wear, chipping, and spalling characteristics of different coating-substrate composites. The test method can be used as a virtually nondestructive test and, for example, be used to evaluate the fatigue and wear resistance as well as the cohesive and adhesive interfacial strength of coated cemented carbide inserts prior to cutting tests.

  3. Production of hard hydrophilic Ni-B coatings on hydrophobic Ni-Ti and Ti-6Al-4V alloys by electroless deposition

    Energy Technology Data Exchange (ETDEWEB)

    Buelbuel, Ferhat; Karabudak, Filiz; Yesildal, Ruhi [Ataturk Univ., Erzurum (Turkey). Mechanical Engineering Dept.

    2017-07-01

    This paper is mainly focused on the wetting state of liquid droplets on Ni-Ti and Ti-6Al-4V hierarchical structured hydrophobic surfaces in micro/nanoscale. Electroless Ni-B deposition as a surface coating treatment has recently drawn considerable attention of researchers owing to remarkable advantages when compared with other techniques such as low price, conformal ability to coat substrates, good bath stability and relatively easier plating process control. The Ni-Ti and Ti-6Al-4V substrates were plated by electroless Ni-B plating process. The coated films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), hardness testing and static contact angle measurement. Results obtained from the analyses show that electroless Ni-B deposition may improve the hardness and wettability of the Ni-Ti and Ti-6Al-4V alloy surfaces.

  4. State-of-the-art tests for evaluating coatings

    International Nuclear Information System (INIS)

    Wallace, B.A.; Thompson, J.C.

    1984-01-01

    This article is not intended to give a complete test program for evaluating coatings, but to supplement the standard referenced tests. Particular tests described emphasize how coating performance is affected by the thermal expansion forces that attempt to prevent anchoring of pipe lines; effects of the wet/dry cycles on buried lines; effect on cathodic disbondment at elevated temperatures, voltages, and pressures; ability to withstand a hot marine mastic pour; temperature cycling, shear and creep tests on concrete-coated pipe, and effects of stinger stress loading

  5. Influence of high temperature annealing on the structure, hardness and tribological properties of diamond-like carbon and TiAlSiCN nanocomposite coatings

    International Nuclear Information System (INIS)

    Xie, Z.W.; Wang, L.P.; Wang, X.F.; Huang, L.; Lu, Y.; Yan, J.C.

    2011-01-01

    Diamond-like carbon (DLC) and TiAlSiCN nanocomposite coatings were synthesized and annealed at different temperatures in a vacuum environment. The microstructure, hardness and tribological properties of as-deposited and annealed DLC-TiAlSiCN nanocomposite coatings were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, nano-indentation and friction tests. The TEM results reveal that the as-deposited DLC-TiAlSiCN coating has a unique nanocomposite structure consisting of TiCN nanocrystals embedded in an amorphous matrix consisting of a-Si 3 N 4 , a-SiC, a-CN and DLC, and the structure changed little after annealing at 800 °C. However, XPS and Raman results show that an obvious graphitization of the DLC phase occurred during the annealing process and it worsened with annealing temperature. Because of the graphitization, the hardness of the DLC-TiAlSiCN coating after annealing at 800 °C decreased from 45 to 36 GPa. In addition, the DLC-TiAlSiCN coating after annealing at 800 °C has a similar friction coefficient to the as-deposited coating.

  6. Nondestructive Evaluation of Carbon-Carbon Coatings

    Science.gov (United States)

    1987-10-01

    4, -4 3 2.0 17-21 15 18 21 :9." -: 4:tes: 1, Cll •easureren’. ;rown ire in Ill e::ceoI ".-ic.-ie: "-.- : .. - are hown in •iai:’l4m raw court form...scatter in the samples rather than the additional formation of cristo - balite. This was supported by later diffraction scans of material after extended...could not be avoided due to the brittle nature of the coating. , b. Coupons were then mounted in epoxy using a vacuum-oimpregnation technique. This

  7. Preparation of multi-layer film consisting of hydrogen-free DLC and nitrogen-containing DLC for conductive hard coating

    Science.gov (United States)

    Iijima, Yushi; Harigai, Toru; Isono, Ryo; Degai, Satoshi; Tanimoto, Tsuyoshi; Suda, Yoshiyuki; Takikawa, Hirofumi; Yasui, Haruyuki; Kaneko, Satoru; Kunitsugu, Shinsuke; Kamiya, Masao; Taki, Makoto

    2018-01-01

    Conductive hard-coating films have potential application as protective films for contact pins used in the electrical inspection process for integrated circuit chips. In this study, multi-layer diamond-like carbon (DLC) films were prepared as conductive hard-coating films. The multi-layer DLC films consisting of DLC and nitrogen-containing DLC (N-DLC) film were prepared using a T-shape filtered arc deposition method. Periodic DLC/N-DLC four-layer and eight-layer films had the same film thickness by changing the thickness of each layer. In the ball-on-disk test, the N-DLC mono-layer film showed the highest wear resistance; however, in the spherical polishing method, the eight-layer film showed the highest polishing resistance. The wear and polishing resistance and the aggressiveness against an opponent material of the multi-layer DLC films improved by reducing the thickness of a layer. In multi-layer films, the soft N-DLC layer between hard DLC layers is believed to function as a cushion. Thus, the tribological properties of the DLC films were improved by a multi-layered structure. The electrical resistivity of multi-layer DLC films was approximately half that of the DLC mono-layer film. Therefore, the periodic DLC/N-DLC eight-layer film is a good conductive hard-coating film.

  8. GEP-based method to formulate adhesion strength and hardness of Nb PVD coated on Ti-6Al-7Nb aimed at developing mixed oxide nanotubular arrays.

    Science.gov (United States)

    Rafieerad, A R; Bushroa, A R; Nasiri-Tabrizi, B; Fallahpour, A; Vadivelu, J; Musa, S N; Kaboli, S H A

    2016-08-01

    PVD process as a thin film coating method is highly applicable for both metallic and ceramic materials, which is faced with the necessity of choosing the correct parameters to achieve optimal results. In the present study, a GEP-based model for the first time was proposed as a safe and accurate method to predict the adhesion strength and hardness of the Nb PVD coated aimed at growing the mixed oxide nanotubular arrays on Ti67. Here, the training and testing analysis were executed for both adhesion strength and hardness. The optimum parameter combination for the scratch adhesion strength and micro hardness was determined by the maximum mean S/N ratio, which was 350W, 20 sccm, and a DC bias of 90V. Results showed that the values calculated in the training and testing in GEP model were very close to the actual experiments designed by Taguchi. The as-sputtered Nb coating with highest adhesion strength and microhardness was electrochemically anodized at 20V for 4h. From the FESEM images and EDS results of the annealed sample, a thick layer of bone-like apatite was formed on the sample surface after soaking in SBF for 10 days, which can be connected to the development of a highly ordered nanotube arrays. This novel approach provides an outline for the future design of nanostructured coatings for a wide range of applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Accompanying of parameters of color, gloss and hardness on polymeric films coated with pigmented inks cured by different radiation doses of ultraviolet light

    International Nuclear Information System (INIS)

    Gonçalves Bardi, Marcelo Augusto; Brocardo Machado, Luci Diva

    2012-01-01

    In the search for alternatives to traditional paint systems solvent-based, the curing process of polymer coatings by ultraviolet light (UV) has been widely studied and discussed, especially because of their high content of solids and null emission of VOC. In UV-curing technology, organic solvents are replaced by reactive diluents, such as monomers. This paper aims to investigate variations on color, gloss and hardness of print inks cured by different UV radiation doses. The ratio pigment/clear coating was kept constant. The clear coating presented higher average values for König hardness than pigmented ones, indicating that UV-light absorption has been reduced by the presence of pigments. Besides, they have indicated a slight variation in function of cure degree for the studied radiation doses range. The gloss loss related to UV light exposition allows inferring that some degradation occurred at the surface of print ink films. - Highlights: ► Color, gloss and hardness are directly influenced by the different pigments. ► Clear coating analysis indicates reduction on UV-light absorption. ► Color and gloss indices indicated aeration in function of cure degree.

  10. Evaluation of several corrosion protective coating systems on aluminum

    Science.gov (United States)

    Higgins, R. H.

    1981-01-01

    A study of several protective coating systems for use on aluminum in seawater/seacoast environments was conducted to review the developments made on protective coatings since early in the Space Shuttle program and to perform comparative studies on these coatings to determine their effectiveness for providing corrosion protection during exposure to seawater/seacoast environments. Panels of 2219-T87 aluminum were coated with 21 different systems and exposed to a 5 percent salt spray for 4000 hr. Application properties, adhesion measurements, heat resistance and corrosion protection were evaluated. For comparative studies, the presently specified Bostik epoxy system used on the SRB structures was included. Results of these tests indicate four systems with outstanding performance and four additional systems with protection almost as good. These systems are based on a chromated pretreatment, a chromate epoxy primer, and a polyurethane topcoat. Consideration for one of these systems should be included for those applications where superior corrosion protection for aluminum surfaces is required.

  11. High-Performance and Simply-Synthesized Ladder-Like Structured Methacrylate Siloxane Hybrid Material for Flexible Hard Coating

    Directory of Open Access Journals (Sweden)

    Yun Hyeok Kim

    2018-04-01

    Full Text Available A high performance ladder-like structured methacrylate siloxane hybrid material (LMSH was fabricated via simple hydrolytic sol–gel reaction, followed by free-radical polymerization. A structurally ordered siloxane backbone, the ladder-like structure, which is an essential factor for high performance, could be achieved by a short period of sol–gel reaction in only 4 h. This results in superior optical (Transmittance > 90% at 550 nm, thermal (T5 wt % decomposition > 400 ℃ , mechanical properties(elastic recovery = 0.86, hardness = 0.6 GPa compared to the random- and even commercialized cage-structured silsesquioxane, which also has ordered structure. It was investigated that the fabricated ladder-like structured MSH showed the highest overall density of organic/inorganic co-networks that are originated from highly ordered siloxane network, along with high conversion rate of polymerizable methacrylate groups. Our findings suggest a potential of the ladder-like structured MSH as a powerful alternative for the methacrylate polysilsesquioxane, which can be applied to thermally stable and flexible optical coatings, even with an easier and simpler preparation process.

  12. Evaluation of Rock Bolt Support for Polish Hard Rock Mines

    Science.gov (United States)

    Skrzypkowski, Krzysztof

    2018-03-01

    The article presents different types of rock bolt support used in Polish ore mining. Individual point resin and expansion rock bolt support were characterized. The roof classes for zinc and lead and copper ore mines were presented. Furthermore, in the article laboratory tests of point resin rock bolt support in a geometric scale of 1:1 with minimal fixing length of 0.6 m were made. Static testing of point resin rock bolt support were carried out on a laboratory test facility of Department of Underground Mining which simulate mine conditions for Polish ore and hard coal mining. Laboratory tests of point resin bolts were carried out, especially for the ZGH Bolesław, zinc and lead "Olkusz - Pomorzany" mine. The primary aim of the research was to check whether at the anchoring point length of 0.6 m by means of one and a half resin cartridge, the type bolt "Olkusz - 20A" is able to overcome the load.The second purpose of the study was to obtain load - displacement characteristic with determination of the elastic and plastic range of the bolt. For the best simulation of mine conditions the station steel cylinders with an external diameter of 0.1 m and a length of 0.6 m with a core of rock from the roof of the underground excavations were used.

  13. Fabrication, performance, and figure metrology of epoxy-replicated aluminum foils for hard x-ray focusing multilayer-coated segmented conical optics

    DEFF Research Database (Denmark)

    Jimenez-Garate, M.A.; Craig, W.W.; Hailey, C.J.

    2000-01-01

    We fabricated x-ray mirrors for hard x-ray (greater than or equal to 10 keV) telescopes using multilayer coatings and an improved epoxy-replicated aluminum foil (ERAF) nonvacuum technology. The ERAF optics have similar to1 arcmin axial figure half-power diameter (HPD) and passed environmental...... telescope HPD, we designed a figure metrology system and a new mounting technique. We describe a cylindrical metrology system built for fast axial and roundness figure measurement of hard x-ray conical optics. These developments lower cost and improve the optics performance of the HEFT (high-energy focusing...

  14. Deposition and characterisation of multilayer hard coatings. Ti/TiNδ/TiCxNy/(TiC) a-C:H/(Ti) a-C:H

    International Nuclear Information System (INIS)

    Burinprakhon, T.

    2001-02-01

    Multilayer hard coatings containing Ti, TiNδ, TiC x N y , (TiC m ) a-C:H, (TiC n ) a-C:H, and (Ti) a-C:H were deposited on commercially pure titanium substrates by using an asymmetric bipolar pulsed-dc reactive magnetron sputtering of a titanium target, with Ar, Ar+N 2 , Ar+N 2 +CH 4 , and Ar+CH 4 gas mixtures. The microstructures, elemental compositions and bonding states of the interlayers and the coating surfaces were studied by using cross-sectional transmission electron microscopy (XTEM), electron energy loss spectroscopy (EELS), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The microstructure development of the multilayer coating was strongly influenced by target poisoning. As a result of the complete poisoning of the titanium target during the deposition of TiNδ and TiC x N y interlayers, the a-C:H interlayers containing graded titanium and nitrogen contents were found to develop successively to the TiC x N y interlayer without the formation of near-stoichiometric TiC. The (TiC m ) a-C:H interlayer consisted of nano-particles of distorted fcc crystal structure embedded in the a-C:H matrix. The (TiC n ) a-C:H and (Ti) a-C:H top layers were found to be a-C:H matrix without nano-particles. In the (Ti) a-C:H top layer there was no measurable amount of Ti observed, regardless of the variation of CH 4 concentration between 37.5 and 60 % flow rate in Ar+-CH4 gas mixture. The top layer (Ti) a-C:H was found to contain approximately 10 atomic % nitrogen, due to N 2 contamination during deposition caused by low conductance of N 2 through the nominally closed valve of the mass flow controller. The change of the CH 4 concentration during deposition of the top layer (Ti) a-C:H, however, showed a strong influence on the hydrogen content. The comparison of the fluorescence background of the Raman spectra revealed that hydrogen-less (Ti) a-C:H was deposited at a CH 4 concentration of less than 50 % flow rate in Ar. The hardness

  15. Bottom Extreme-Ultraviolet-Sensitive Coating for Evaluation of the Absorption Coefficient of Ultrathin Film

    Science.gov (United States)

    Hijikata, Hayato; Kozawa, Takahiro; Tagawa, Seiichi; Takei, Satoshi

    2009-06-01

    A bottom extreme-ultraviolet-sensitive coating (BESC) for evaluation of the absorption coefficients of ultrathin films such as extreme ultraviolet (EUV) resists was developed. This coating consists of a polymer, crosslinker, acid generator, and acid-responsive chromic dye and is formed by a conventional spin-coating method. By heating the film after spin-coating, a crosslinking reaction is induced and the coating becomes insoluble. A typical resist solution can be spin-coated on a substrate covered with the coating film. The evaluation of the linear absorption coefficients of polymer films was demonstrated by measuring the EUV absorption of BESC substrates on which various polymers were spin-coated.

  16. The limits of application of variable-energy slow positron beams for investigating TiN hard coatings prepared by PVD

    International Nuclear Information System (INIS)

    Marek, T.; Suevegh, K.; Vertes, A.; Szeles, Cs.; Lynn, K.G.

    2000-01-01

    Samples of TiN hard coatings prepared by physical vapour deposition (PVD) were investigated by means of depth-sensitive positron annihilation spectroscopy. The results indicate that the samples are at the limits of the applicability of this method presumably due to the high defect concentration. Though the samples are thoroughly characterized by other independent methods, they might not be sufficient to explain all aspects of positron-solid interactions in these cases. (author)

  17. Evaluation of hard gelatin capsules and hydroxypropyl methylcellulose containing ampicillin

    Directory of Open Access Journals (Sweden)

    Graziella Gonçalves Weigert

    2012-01-01

    Full Text Available This study aims to develop and evaluate formulations containing ampicillin in capsules of gelatin and hydroxypropyl methylcellulose (HPMC. Two formulations (A and B were developed. The final product quality was evaluated by testing for quality control and the results were in agreement with the Brazilian Pharmacopoeia. The formulations with HPMC capsules showed lower percentages of drug dissolved (99.67%, HPMC-A and 87.70%, HPMC-B than the gelatin (100.18%, GEL-A and 101.16% GEL-B. Because of the delay of the ampicillin release observed in the dissolution profiles, it becomes necessary to evaluate the drugs that can be conditioned in the HPMC capsules.

  18. Stability and drug dissolution evaluation of Qingkailing soft/hard ...

    African Journals Online (AJOL)

    Purpose: To carry out a post-marketing evaluation of the stability and drug dissolution of ... Stability data from long-term studies showed that within 6 months the ... However, fingerprint pattern statistical analysis showed that the soft capsule is ...

  19. Evaluation of ERINA Plus as a coat conditioner in canines

    Directory of Open Access Journals (Sweden)

    Srivastava

    Full Text Available Coat conditioning, deodorant and cleansing properties of ERINA Plus were evaluated in fifty-one dogs of different breeds. More than 80% of dogs showed good to excellent conditioning, deodorant and cleansing effects supported ERINA Plus as safe conditioner shampoo. [Vet. World 2008; 1(12.000: 361-362

  20. Spalling stress in oxidized thermal barrier coatings evaluated by X-ray diffraction method

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, K. [Faculty of Education and Human Sciences, Niigata Univ., Niigata (Japan); Tanaka, K. [Dept. of Mechanical Engineering, Nagoya Univ., Furoh-cho, Chikusa-ku, Nagoya (Japan)

    2005-07-01

    The spallation of thermal barrier coatings (TBCs) is promoted by thermally grown oxide (TGO). To improve TBCs, it is very important to understand the influence of TGO on the spalling stress. In this study 'the TBCs were oxidized at 1373 K for four different periods: 0, 500,1000 and 2000 h. The distribution of the in-plane stress in oxidized TBCs, {sigma}{sub 1}, was obtained by repeating the X-ray stress measurement with low energy X-rays after successive removal of the surface layer. The distribution of the out-of-plane stress, {sigma}{sub 1} - {sigma}{sub 3}, was measured with hard synchrotron X-rays, because high energy X-rays have a large penetration depth. From the results by the low and high energy X-rays, the spalling stress in the oxidized TBCs, {sigma}{sub 3}, was evaluated. The evaluated value of the spalling stress for the oxidized TBC was a small tension beneath the surface, but steeply increased near the interface between the top and bond coating. This large tensile stress near the interface is responsible for the spalling of the top coating. (orig.)

  1. Evaluation of hot hardness, creep, fatigue and fracture properties of zirconia ceramics by an indentation technique

    International Nuclear Information System (INIS)

    Kutty, T.R.G.; Ganguly, C.; Upadhyaya, D.D.

    1996-01-01

    Zirconia ceramics have wide range engineering applications at room and elevated temperatures. For understanding the mechanical behaviour, the indentation technique was adapted for quick evaluation of hot hardness, creep, fatigue and fracture properties. A Vicker's diamond indentor with 10 N load was employed for hot hardness and creep measurement up to 1300 deg. The fatigue data were evaluated at room temperature by repeated indentation with a constant load (10-2500N) at the same location for a dwell time of 5s until it resulted in the formation of a lateral chip on the sample surface. Thus, the number of cycles for chip formation at a specific indentation load was obtained. The fracture toughness was evaluated at room temperature with a load of 300N using a Vicker's diamond indentor. The results of hot hardness, creep, fatigue, and fracture data ol 3Y-TZP and Mg-PSZ are discussed along with their microstructural features. (authors)

  2. New method for evaluating high-quality fog protective coatings

    Science.gov (United States)

    Czeremuszkin, Grzegorz; Latreche, Mohamed; Mendoza-Suarez, Guillermo

    2011-05-01

    Fogging is commonly observed when humid-warm air contacts the cold surface of a transparent substrate, i.e. eyewear lenses, making the observed image blurred and hazy. To protect from fogging, the lens inner surfaces are protected with Anti-Fog coatings, which render them hydrophilic and induce water vapor condensation as a smooth, thin and invisible film, which uniformly flows down on the lens as the condensation progresses. Coatings differ in protection level, aging kinetics, and susceptibility to contamination. Some perform acceptably in limited conditions, beyond which the condensing water film becomes unstable, nonuniform, and scatters light or shows refractory distortions, both affecting the observed image. Quantifying the performance of Anti-Fog coated lenses is difficult: they may not show classical fogging and the existing testing methods, based on fog detection, are therefore inapplicable. The presented method for evaluating and quantifying AF properties is based on characterizing light scattering on lenses exposed to controlled humidity and temperature. Changes in intensity of laser light scattered at low angles (1, 2 4 and 8 degrees), observed during condensation of water on lenses, provide information on the swelling of Anti-Fog coatings, formation of uniform water film, going from an unstable to a steady state, and on the coalescence of discontinuous films. Real time observations/measurements allow for better understanding of factors controlling fogging and fog preventing phenomena. The method is especially useful in the development of new coatings for military-, sport-, and industrial protective eyewear as well as for medical and automotive applications. It allows for differentiating between coatings showing acceptable, good, and excellent performance.

  3. Evaluation of workers exposed to dust containing hard metals and aluminum oxide.

    Science.gov (United States)

    Schwarz, Y; Kivity, S; Fischbein, A; Abraham, J L; Fireman, E; Moshe, S; Dannon, Y; Topilsky, M; Greif, J

    1998-08-01

    Fourteen worker exposed to hard metals and aluminum oxide were evaluated. Six heavily exposed workers underwent bronchoscopy and bronchoalveolar lavage, and five workers underwent transbronchial biopsy. Microchemical analysis of transbronchial biopsies showed a high lung burden of exogenous particles, especially metal related to their hard metals exposure. Lung tissue and cellular changes, which were associated with exposure to hard metal and aluminum oxide, corresponded well with the microanalytic test results. Three workers had at biopsy diffuse interstitial inflammatory changes: two of them were asymptomatic with normal chest X-ray films, and one had clinically evident disease with severe giant cell inflammation. Two other workers showed focal inflammation. The worker showing clinical disease and one asymptomatic worker with interstitial inflammatory changes had evaluated bronchoalveolar lavage fluid-eosinophilia counts. These two were father (with clinical disease) and son (asymptomatic).

  4. Development and evaluation of a hot-melt coating technique for enteric coating

    Directory of Open Access Journals (Sweden)

    Arun Trambak Patil

    2012-03-01

    Full Text Available Conventional enteric coating requires the use of organic based polymers which are equally hazardous to the environment and operating personnel. Hot-melt coating avoids the use of solvents and is a safer and time-saving process. The present study was designed to assess the efficacy of hot-melt coating (HMC as an enteric coating technique. Pellets prepared by extrusion spheronization were selected as the core formulation for a model of the gastric irritant drug diclofenac sodium (DFS because of their innate advantages over single-unit formulations. Stearic acid (SA and palmitic acid (PA were evaluated as enteric hot-melt coating materials. HMC was carried out in a specially modified coating pan by applying SA and PA in molten state onto preheated pellets to achieve a coating level of 5-15 %w/w. Hot-melt coated pellets were evaluated for disintegration pH and in vitro dissolution in the pH range 1.2 to 6.8, along with basic micromeritics. SEM of coated pellets showed a uniform and smooth coating. These results indicated that HMC of both SA and PA exhibited very good enteric coating ability. The coated pellets showed negligible drug release in acidic pH. As the pellets were subsequently transferred to a higher pH level, a gradual increase in release of the drug from the pellets was observed with increasing pH of the dissolution media. The release was dependent upon coating extent, providing sustained enteric release as opposed to abrupt release with mixed release kinetics.O revestimento entérico convencional requer o uso de polímeros orgânicos os quais são igualmente danosos ao meio ambiente e ao pessoal que o executa. O revestimento por fusão a quente evita o uso de solventes e é processo mais seguro e que consome menos tempo. O presente estudo foi planejado para avaliar a eficácia do revestimento por fusão a quente (RFQ como técnica de revestimento entérico. Os péletes preparados por esferonização por extrusão foram selecionados como

  5. Cathode-sputtered Ti-Zr-N-C-O base hard coatings and stability of said coatings on hard metals and working steels. Kathodenzerstaeubte Hartstoffschichten auf Basis Ti-Zr-N-C-O und deren Stabilitaet auf Hartmetall und Gebrauchsstaehlen

    Energy Technology Data Exchange (ETDEWEB)

    Boehmer, M.

    1986-02-26

    This paper deals with the examination of the metallurgical and thermal stability of the resistant material layers of titanium in connection with the substrate material influence. As substrate material were chosen: hard metal (81% WC, 12% TiC+TaC, 7% Co), high speed steel (DIN 1.3343), austenitic nickel chromium steel (X5 CrNi 18 9) and unalloyed tool steel (DIN 1.1545). The hard materials of titanium were deposited by means of cathode evaporation.

  6. Damage phenomena of thin hard coatings submitted to repeated impacts: Influence of the substrate and film properties

    Energy Technology Data Exchange (ETDEWEB)

    Lamri, S. [IRTES-LERMPS, EA 7274, UTBM, 90 010 Belfort Cedex (France); ICD-LASMIS, UTT antenne de Nogent, Rue Lavoisier, 52800 Nogent (France); Langlade, C., E-mail: cecile.langlade@utbm.fr [IRTES-LERMPS, EA 7274, UTBM, 90 010 Belfort Cedex (France); Kermouche, G. [LTDS Laboratory, UMR CNRS 5513, ENI St Etienne (France); UMR CNRS 5146, Ecole des Mines de St-Etienne, Centre SMS, 158 Cours Fauriel, 42100 St-Etienne (France)

    2013-01-10

    To evaluate the surface fatigue resistance of some thin nitride films obtained by Physical Vapour Deposition (PVD) techniques, repeated impact tests have been performed under controlled impact conditions. Short and long duration tests have revealed the occurrence of an original damage phenomenon likely linked to a mechanical blistering of the films. As these blisters appear to be the first damage step, their formation has to be understood in order to be avoided in industrial applications. In particular, the role of the mechanical properties of the substrate has to be clarified as thin protective coatings may be used on pieces prepared using various heat treatments. finite element method (FEM) analysis has been conducted in order to better understand the specific mechanical conditions in the substrate and at the film-substrate interface that could lead to such blistering phenomena. Correlations with the experimental results have been evidenced. From the modelling results the substrate properties have been shown to be of significant influence on the blister formation. However as they do not fully explain the origin of this phenomenon, the influence of the substrate microstructure has also been studied and the presence of vanadium carbides appears to be of major effect.

  7. Performance evaluation of one coat systems for new steel bridges.

    Science.gov (United States)

    2011-06-01

    In an effort to address cost issues associated with shop application of conventional three-coat systems, the Federal : Highway Administration completed a study to investigate the performance of eight one-coat systems and two control : coatings for co...

  8. Roughness Influence On Macro- And Micro-Tribology Of Multi-Layered Hard Coatings On Carbon Fibre Polymer Composite

    Directory of Open Access Journals (Sweden)

    Lackner J.M.

    2015-09-01

    Full Text Available Goal of this work is the investigation of roughness influences on the abrasive wear behaviour of magnetron sputtered multi-layered, low-friction coatings on carbon-fibre reinforced polymers (CFRP. Higher coating roughness at similar CFRP quality was realized by higher deposition rates, leading to increased heat flux to the substrates during deposition. Thermal expansion of the epoxy matrix on the micro scale results in a wavy, wrinkled surface topography. Both in scratch and reciprocal sliding testing against alumina, the friction coefficients are lower for the smooth coatings, but their wear rate is higher due to low-cycle fatigue caused abrasion.

  9. Evaluation of the Commercial off-the-shelf (COTS) Low Temperature Powder Coating (LTPC)

    Science.gov (United States)

    2017-11-15

    CONTRACT NUMBER: FA8532-17-C-0008 (CDRL A001) Evaluation of the Commercial off- the-shelf (COTS) Low Temperature Powder Coating (LTPC...3 Evaluation of the COTS LTPC (CDRL A001) BATTELLE 1 1.0 Introduction...primers in traditional coating systems is costly, time consuming , and represents a risk to health, safety, and the environment. Powder coatings

  10. Evaluation of a reflective coating for an organic scintillation detector

    International Nuclear Information System (INIS)

    Tarancón, A.; Marin, E.; Tent, J.; Rauret, G.; Garcia, J.F.

    2012-01-01

    A reflective coating based on white paint, black paint and varnish has been evaluated to determine its reflective capabilities and its potential use in radioactivity detectors based on organic scintillators. Three different white paints, all of which were based on TiO 2 , were also tested to determine the one with the best performance and lowest radioactivity content. In a first experiment, we evaluated the capability of the reflective coating by measuring 90 Sr/ 90 Y with PSm in a polyethylene vial partially painted with EJ510 (Eljen Technology) reflective paint, black paint and varnish. In a second experiment, we compared the performance of the EJ510 to that of other white paints used for artistic purposes (Vallejo and Rembrandt). The results showed that, when a vial was only partially painted with the white paints (keeping a window free of paint to allow photons to exit), the efficiency and spectral distribution of the painted vial was similar to that of a non-painted vial. This behavior showed the efficiency of the reflective coatings. In terms of reflection capabilities, all of the tested paints were equivalent; however, the background was higher for the EJ510 paint. Analyses using high-resolution gamma spectroscopy indicated the presence of natural radionuclides ( 40 K, 226 Ra and 228 Ra) in the EJ510. On the basis of the results (high reflection capabilities and the absence of radioactive impurities) and its lower cost, the Vallejo paint was selected as the white reflective paint. The final structure of the reflective coating was composed of five white paint layers, a black paint (to avoid external light entrance) and a layer of varnish (to protect the paints).

  11. Evaluation of a reflective coating for an organic scintillation detector

    Science.gov (United States)

    Tarancón, A.; Marin, E.; Tent, J.; Rauret, G.; Garcia, J. F.

    2012-05-01

    A reflective coating based on white paint, black paint and varnish has been evaluated to determine its reflective capabilities and its potential use in radioactivity detectors based on organic scintillators. Three different white paints, all of which were based on TiO2, were also tested to determine the one with the best performance and lowest radioactivity content. In a first experiment, we evaluated the capability of the reflective coating by measuring 90Sr/90Y with PSm in a polyethylene vial partially painted with EJ510 (Eljen Technology) reflective paint, black paint and varnish. In a second experiment, we compared the performance of the EJ510 to that of other white paints used for artistic purposes (Vallejo and Rembrandt). The results showed that, when a vial was only partially painted with the white paints (keeping a window free of paint to allow photons to exit), the efficiency and spectral distribution of the painted vial was similar to that of a non-painted vial. This behavior showed the efficiency of the reflective coatings. In terms of reflection capabilities, all of the tested paints were equivalent; however, the background was higher for the EJ510 paint. Analyses using high-resolution gamma spectroscopy indicated the presence of natural radionuclides (40K, 226Ra and 228Ra) in the EJ510. On the basis of the results (high reflection capabilities and the absence of radioactive impurities) and its lower cost, the Vallejo paint was selected as the white reflective paint. The final structure of the reflective coating was composed of five white paint layers, a black paint (to avoid external light entrance) and a layer of varnish (to protect the paints).

  12. Evaluation of a reflective coating for an organic scintillation detector

    Energy Technology Data Exchange (ETDEWEB)

    Tarancon, A., E-mail: alex.tarancon@ub.edu [Department of Analytical Chemistry of the University of Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Marin, E. [Department of Analytical Chemistry of the University of Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Tent, J. [Servei d' analisis isotopics of the University of Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Rauret, G.; Garcia, J.F. [Department of Analytical Chemistry of the University of Barcelona, Diagonal 647, E-08028 Barcelona (Spain)

    2012-05-11

    A reflective coating based on white paint, black paint and varnish has been evaluated to determine its reflective capabilities and its potential use in radioactivity detectors based on organic scintillators. Three different white paints, all of which were based on TiO{sub 2}, were also tested to determine the one with the best performance and lowest radioactivity content. In a first experiment, we evaluated the capability of the reflective coating by measuring {sup 90}Sr/{sup 90}Y with PSm in a polyethylene vial partially painted with EJ510 (Eljen Technology) reflective paint, black paint and varnish. In a second experiment, we compared the performance of the EJ510 to that of other white paints used for artistic purposes (Vallejo and Rembrandt). The results showed that, when a vial was only partially painted with the white paints (keeping a window free of paint to allow photons to exit), the efficiency and spectral distribution of the painted vial was similar to that of a non-painted vial. This behavior showed the efficiency of the reflective coatings. In terms of reflection capabilities, all of the tested paints were equivalent; however, the background was higher for the EJ510 paint. Analyses using high-resolution gamma spectroscopy indicated the presence of natural radionuclides ({sup 40}K, {sup 226}Ra and {sup 228}Ra) in the EJ510. On the basis of the results (high reflection capabilities and the absence of radioactive impurities) and its lower cost, the Vallejo paint was selected as the white reflective paint. The final structure of the reflective coating was composed of five white paint layers, a black paint (to avoid external light entrance) and a layer of varnish (to protect the paints).

  13. Electrodeposition and properties of Zn-Ni-CNT composite coatings

    International Nuclear Information System (INIS)

    Praveen, B.M.; Venkatesha, T.V.

    2009-01-01

    Zn-Ni-CNT composite coatings were prepared by electrodeposition from a sulphate bath. The effect of CNTs on the corrosion behavior, wear resistance and hardness of the composite coatings was investigated. Their corrosion properties were evaluated by polarization, impedance, weight loss and salt spray tests. The CNT particles inclusion improved the corrosion resistance, hardness and wear resistance of the coating. The grain size of the composite coating was smaller than that of a pure Zn-Ni coating with the same Zn/Ni ratio. Scanning electron microscope images and X-ray diffraction patterns of coating revealed its fine-grain nature.

  14. Development of wear-resistant coatings for cobalt-base alloys

    International Nuclear Information System (INIS)

    Cockeram, B.V.

    1999-01-01

    The costs and hazards resulting from nuclear plant radiation exposure with activated cobalt wear debris could potentially be reduced by covering the cobalt-base materials with a wear resistant coating. However, the hardnesses of many cobalt-base wear alloys are significantly lower than conventional PVD hard coatings, and mechanical support of the hard coating is a concern. Four approaches have been taken to minimize the hardness differences between the substrate and PVD hard coating: (1) use a thin Cr-nitride hard coating with layers that are graded with respect to hardness, (2) use a thicker, multilayered coating (Cr-nitride or Zr-nitride) with graded layers, (3) use nitriding to harden the alloy subsurface followed by application of a multilayered coating of Cr-nitride, and (4) use of nitriding alone. Since little work has been done on application of PVD hard coatings to cobalt-base alloys, some details on process development and characterization of the coatings is presented. Scratch testing was used to evaluate the adhesion of the different coatings. A bench-top rolling contact test was used to evaluate the wear resistance of the coatings. The test results are discussed, and the more desirable coating approaches are identified

  15. Development of nondestructive evaluation methods for ceramic coatings

    International Nuclear Information System (INIS)

    Ellingson, W. A.; Deemer, C.; Sun, J. G.; Erdman, S.; Muliere, D.; Wheeler, B.

    2002-01-01

    Various nondestructive evaluation (NDE) technologies are being developed to study the use of ceramic coatings on components in the hot-gas path of advanced low-emission gas-fired turbines. The types of ceramic coatings include thermal barrier coatings (TBCs) and environmental barrier coatings (EBCs). TBCs are under development for vanes, blades, and combustor liners to allow hotter gas-path temperatures, and EBCs are under development to reduce environmental damage to high-temperature components made of ceramic matrix composites. The NDE methods will be used to (a) provide data to assess the reliability of new coating application processes, (b) identify defective components that could cause unscheduled outages, (c) track growth rates of defects during component use in engines, and (d) allow rational judgment for replace/repair/re-use decisions regarding components. Advances in TBC application, both electron beam-physical vapor deposition (EB-PVD) and air plasma spraying (APS), are allowing higher temperatures in the hot-gas path. However, as TBCs become ''prime reliant,'' their condition at scheduled or unscheduled outages must be known. NDE methods are under development to assess the condition of the TBC for pre-spall conditions. EB-PVD test samples with up to 70 thermal cycles have been studied by a newly developed method involving polarized laser back-scatter NDE. Results suggest a correlation between the NDE laser data and the TBC/bond-coat topography. This finding is important because several theories directed toward understanding the pre-spall condition suggest that the topography in the thermally grown oxide layer changes significantly as a function of the number of thermal cycles. Tests have also been conducted with this NDE method on APS TBCs. Results suggest that the pre-spall condition is detected for these coatings. One-sided, high-speed thermal imaging also has shown promise for NDE of APS coatings. Testing of SiC/SiC composites for combustor liners

  16. Performance Evaluation of Refractory Composite Coatings in Potassium Rich Environment

    Directory of Open Access Journals (Sweden)

    Kristina BRINKIENĖ

    2016-09-01

    Full Text Available A laboratory scale method was used to study the performance of reinforced cement composites in potassium rich environment of biomass combustion. Buckwheat husk (BH was used as potential source of unexploited biomass product applicable as biomass derived fuel. In order to enhance the alkali effect on the properties of the investigated materials, the solution of potassium carbonate (K2CO3 was selected as potassium rich aggressive environment. Two reinforced cement composites as potential repair coatings for restoration of damaged refractory surfaces with different composition of aggregate were used in corrosion tests. Performance of refractory coatings was evaluated by analysing the microstructure of the treated composites as well as mechanical properties. Energy-dispersive X-ray spectroscopy (SEM/EDS and optical microscopy were used to study the microstructure in the corroded region of the refractory coatings. Long term studies in the solution of 1M K2CO3 for 56 months have demonstrated that composite with the additive of fluid cracking catalyst of oil refinery and petrochemical industries is more durable in the potassium rich environment.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.8348

  17. Evaluation of stiffness feedback for hard nodule identification on a phantom silicone model.

    Science.gov (United States)

    Li, Min; Konstantinova, Jelizaveta; Xu, Guanghua; He, Bo; Aminzadeh, Vahid; Xie, Jun; Wurdemann, Helge; Althoefer, Kaspar

    2017-01-01

    Haptic information in robotic surgery can significantly improve clinical outcomes and help detect hard soft-tissue inclusions that indicate potential abnormalities. Visual representation of tissue stiffness information is a cost-effective technique. Meanwhile, direct force feedback, although considerably more expensive than visual representation, is an intuitive method of conveying information regarding tissue stiffness to surgeons. In this study, real-time visual stiffness feedback by sliding indentation palpation is proposed, validated, and compared with force feedback involving human subjects. In an experimental tele-manipulation environment, a dynamically updated color map depicting the stiffness of probed soft tissue is presented via a graphical interface. The force feedback is provided, aided by a master haptic device. The haptic device uses data acquired from an F/T sensor attached to the end-effector of a tele-manipulated robot. Hard nodule detection performance is evaluated for 2 modes (force feedback and visual stiffness feedback) of stiffness feedback on an artificial organ containing buried stiff nodules. From this artificial organ, a virtual-environment tissue model is generated based on sliding indentation measurements. Employing this virtual-environment tissue model, we compare the performance of human participants in distinguishing differently sized hard nodules by force feedback and visual stiffness feedback. Results indicate that the proposed distributed visual representation of tissue stiffness can be used effectively for hard nodule identification. The representation can also be used as a sufficient substitute for force feedback in tissue palpation.

  18. Evaluation of stiffness feedback for hard nodule identification on a phantom silicone model.

    Directory of Open Access Journals (Sweden)

    Min Li

    Full Text Available Haptic information in robotic surgery can significantly improve clinical outcomes and help detect hard soft-tissue inclusions that indicate potential abnormalities. Visual representation of tissue stiffness information is a cost-effective technique. Meanwhile, direct force feedback, although considerably more expensive than visual representation, is an intuitive method of conveying information regarding tissue stiffness to surgeons. In this study, real-time visual stiffness feedback by sliding indentation palpation is proposed, validated, and compared with force feedback involving human subjects. In an experimental tele-manipulation environment, a dynamically updated color map depicting the stiffness of probed soft tissue is presented via a graphical interface. The force feedback is provided, aided by a master haptic device. The haptic device uses data acquired from an F/T sensor attached to the end-effector of a tele-manipulated robot. Hard nodule detection performance is evaluated for 2 modes (force feedback and visual stiffness feedback of stiffness feedback on an artificial organ containing buried stiff nodules. From this artificial organ, a virtual-environment tissue model is generated based on sliding indentation measurements. Employing this virtual-environment tissue model, we compare the performance of human participants in distinguishing differently sized hard nodules by force feedback and visual stiffness feedback. Results indicate that the proposed distributed visual representation of tissue stiffness can be used effectively for hard nodule identification. The representation can also be used as a sufficient substitute for force feedback in tissue palpation.

  19. Effect of Pulse Width on Microstructure and Hardness of FeSiB Coatings by Laser Cladding

    Directory of Open Access Journals (Sweden)

    GONG Yu-bing

    2018-03-01

    Full Text Available High-density coating with FeSiB amorphous ribbons as cladding materials on the surface of mild steel was fabricated by laser cladding. The effect of different pulse widths on formability, microstructure and microhardness of the coatings was analyzed by optical microscope(OM, X-ray diffractometer (XRD, scanning electron microscope (SEM and microhardness tester. The results show that with the increase of the pulse width, the coating dilute rate rises; the tendency of crack increases and the crack originates from surface to the interface; the degree of crystallization increases and crystallization phases are α-Fe, Fe2B and Fe3Si, fusion zone width increases and the trend of columnar crystals along the epitaxial growth becomes bigger and bigger; the microhardness firstly increases and then decreases. When pulse width is 3.2ms, the structure of the coating is compact, no hole defects, the interface exhibits a good metallurgical combination and the dilute rate is low about 23.2%. Average microhardness of the coating reaches 1192HV, which is about 10 times as much as the substrate.

  20. Quantitative Image Analysis for Evaluating the Coating Thickness and Pore Distribution in Coated Small Particles

    NARCIS (Netherlands)

    Laksmana, F.L.; Van Vliet, L.J.; Hartman Kok, P.J.A.; Vromans, H.; Frijlink, H.W.; Van der Voort Maarschalk, K.

    2008-01-01

    Purpose This study aims to develop a characterization method for coating structure based on image analysis, which is particularly promising for the rational design of coated particles in the pharmaceutical industry. Methods The method applies the MATLAB image processing toolbox to images of coated

  1. Quantitative Image Analysis for Evaluating the Coating Thickness and Pore Distribution in Coated Small Particles

    NARCIS (Netherlands)

    Laksmana, F L; Van Vliet, L J; Hartman Kok, P J A; Vromans, H; Frijlink, H W; Van der Voort Maarschalk, K

    This study aims to develop a characterization method for coating structure based on image analysis, which is particularly promising for the rational design of coated particles in the pharmaceutical industry. The method applies the MATLAB image processing toolbox to images of coated particles taken

  2. Accompanying of parameters of color, brightness and hardness on polymeric films coated with pigmented inks cured by different radiation doses of ultraviolet light

    International Nuclear Information System (INIS)

    Bardi, M.A.G.; Machado, L.D.B.

    2011-01-01

    Complete text of publication follows. In the search for alternatives to traditional paint systems containing solvents, the curing process of polymer coatings by ultraviolet (UV) light has been widely studied and discussed, specially because of their high content of solids and null emission of VOCs. Radiation curing is defined as the conversion of a reactive liquid into a solid through polymerization and crosslinking reactions between the species, promoted by the interaction of the chemical system with the incident ionizing radiation. The appearance of the coated object (e.g., color, gloss) is a complex function of the light incident on the object, the optical scattering characteristic of the material, and human perception. Pigments are very fine powders being nearly insoluble in binders and solvents, but provide color and the ability to hide the underlying surface. In this context, this paper aims to investigate variations on color, brightness and hardness of UV-cured pigmented coatings by different doses. When it comes to irradiation exposition, the incorporation of pigments can preferentially cause its reflection or absorption of the incident radiation. Reflection usually occurs at the pigment surface within the resin so that the radiation has to pass through the top layers twice. Some degradation can, therefore, occur at the surface, and this is why materials frequently lose gloss on exposure.

  3. Silica-Based and Borate-Based, Titania-Containing Bioactive Coatings Characterization: Critical Strain Energy Release Rate, Residual Stresses, Hardness, and Thermal Expansion

    Directory of Open Access Journals (Sweden)

    Omar Rodriguez

    2016-12-01

    Full Text Available Silica-based and borate-based glass series, with increasing amounts of TiO2 incorporated, are characterized in terms of their mechanical properties relevant to their use as metallic coating materials. It is observed that borate-based glasses exhibit CTE (Coefficient of Thermal Expansion closer to the substrate’s (Ti6Al4V CTE, translating into higher mode I critical strain energy release rates of glasses and compressive residual stresses and strains at the coating/substrate interface, outperforming the silica-based glasses counterparts. An increase in the content of TiO2 in the glasses results in an increase in the mode I critical strain energy release rate for both the bulk glass and for the coating/substrate system, proving that the addition of TiO2 to the glass structure enhances its toughness, while decreasing its bulk hardness. Borate-based glass BRT3, with 15 mol % TiO2 incorporated, exhibits superior properties overall compared to the other proposed glasses in this work, as well as 45S5 Bioglass® and Pyrex.

  4. Fabrication of nanoporous Sr incorporated TiO{sub 2} coating on 316L SS: Evaluation of bioactivity and corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Anne Pauline, S. [Department of Chemistry, Anna University, Chennai 600025 (India); Kamachi Mudali, U. [Corrosion Science and Technology Section, IGCAR, Kalpakkam 603102 (India); Rajendran, N., E-mail: nrajendran@annauniv.edu [Department of Chemistry, Anna University, Chennai 600025 (India)

    2013-10-01

    In this paper, nanoporous TiO{sub 2} and Sr-incorporated TiO{sub 2} coated 316L SS were prepared by sol–gel methodology. The effect of Sr incorporation into TiO{sub 2} coating on bioactivity and corrosion resistance was investigated. Attenuated total reflectance–Fourier transform infrared (ATR–FTIR) spectroscopy, X-ray diffraction analysis (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) results obtained after in vitro bioactivity test confirm the excellent growth of crystalline hydroxyapatite (HAp) over nanoporous Sr-incorporated TiO{sub 2} coated 316L SS which may be attributed to the slow and steady release of Sr ions from the coatings. The electrochemical evaluation of the coatings confirms that Sr-incorporated TiO{sub 2} coating offer excellent protection to 316L SS by acting as a barrier layer. The results showed that the incorporation of Sr enhanced both bioactivity and corrosion resistance of 316L SS. Hence Sr-incorporated TiO{sub 2} coated 316L SS is a promising material for orthopaedic implant applications. - Highlights: • Nanoporous Sr-incorporated TiO{sub 2} coatings were successfully fabricated on 316L SS. • The coatings have excellent adhesion to the substrate and appreciable Vickers micro hardness value. • Sr-incorporated TiO{sub 2} coated specimens exhibited excellent hydroxyapatite growth due to slow release of Sr from the coating. • Sr incorporation enhances the corrosion resistance of TiO{sub 2} coating.

  5. Evaluation of the mechanical properties of microarc oxidation coatings and 2024 aluminium alloy substrate

    CERN Document Server

    Xue Wen Bin; Deng Zhi Wei; Chen Ru Yi; Li Yong Liang; Zhang Ton Ghe

    2002-01-01

    A determination of the phase constituents of ceramic coatings produced on Al-Cu-Mg alloy by microarc discharge in alkaline solution was performed using x-ray diffraction. The profiles of the hardness, H, and elastic modulus, E, across the ceramic coating were determined by means of nanoindentation. In addition, a study of the influence of microarc oxidation coatings on the tensile properties of the aluminium alloy was also carried out. The results show that the H-and E-profiles are similar, and both of them exhibit a maximum value at the same depth of coating. The distribution of the alpha-Al sub 2 O sub 3 phase content determines the H- and E-profiles of the coatings. The tensile properties of 2024 aluminium alloy show less change after the alloy has undergone microarc discharge surface treatment.

  6. Evaluation of hydrogen-Induced cracking resistance of the In625 laser coating system on a C-Mn steel substrate

    Directory of Open Access Journals (Sweden)

    Vicente Braz Trindade

    Full Text Available Abstract The corrosion of C-Mn steels in the presence of hydrogen sulfide (H2S represents a significant challenge to oil production and natural gas treatment facilities. The failure mechanism induced by hydrogen-induced cracking (HIC in a Inconel 625 coating / C-Mn steel has not been extensively investigated in the past. In the present work, an API 5CT steel was coated with In625 alloy using laser cladding and the HIC resistance of different regions, such as the coating surface, the substrate and HAZ, were evaluated. SEM observations illustrated that all HIC cracks were formed at the hard HAZ after 96h of exposure. No HIC cracks were observed in the substrate and the In625 coating after the same exposure duration. Pitting was recorded in the substrate caused by non-metallic inclusion dissolving.

  7. Evaluation of glass transition temperature and dynamic mechanical properties of autopolymerized hard direct denture reline resins.

    Science.gov (United States)

    Takase, Kazuma; Watanabe, Ikuya; Kurogi, Tadafumi; Murata, Hiroshi

    2015-01-01

    This study assessed methods for evaluation of glass transition temperature (Tg) of autopolymerized hard direct denture reline resins using dynamic mechanical analysis and differential scanning calorimetry in addition to the dynamic mechanical properties. The Tg values of 3 different reline resins were determined using a dynamic viscoelastometer and differential scanning calorimeter, and rheological parameters were also determined. Although all materials exhibited higher storage modulus and loss modulus values, and a lower loss tangent at 37˚C with a higher frequency, the frequency dependence was not large. Tg values obtained by dynamic mechanical analysis were higher than those by differential scanning calorimetry and higher frequency led to higher Tg, while more stable Tg values were also obtained by that method. These results suggest that dynamic mechanical analysis is more advantageous for characterization of autopolymerized hard direct denture reline resins than differential scanning calorimetry.

  8. Performance Evaluation of Received Signal Strength Based Hard Handover for UTRAN LTE

    DEFF Research Database (Denmark)

    Anas, Mohmmad; Calabrese, Francesco Davide; Mogensen, Preben

    2007-01-01

    This paper evaluates the hard handover performance for UTRAN LTE system. The focus is on the impact that received signal strength based hard handover algorithm have on the system performance measured in terms of number of handovers, time between two consecutive handovers and uplink SINR for a user...... about to experience a handover. A handover algorithm based on received signal strength measurements has been designed and implemented in a dynamic system level simulator and has been studied for different parameter sets in a 3GPP UTRAN LTE recommended simulation scenario. The results suggest...... that a downlink measurement bandwidth of 1.25 MHz and a handover margin of 2 dB to 6 dB are the parameters that will lead to the best compromise between average number of handovers and average uplink SINR for user speeds of 3 kmph to 120 kmph....

  9. Evaluation of nanohydroxyapaptite (nano-HA) coated epigallocatechin-3-gallate (EGCG) cross-linked collagen membranes.

    Science.gov (United States)

    Chu, Chenyu; Deng, Jia; Man, Yi; Qu, Yili

    2017-09-01

    Collagen is the main component of extracellular matrix (ECM) with desirable biological activities and low antigenicity. Collagen materials have been widely utilized in guided bone regeneration (GBR) surgery due to its abilities to maintain space for hard tissue growth. However, pure collagen lacks optimal mechanical properties. In our previous study, epigallocatechin-3-gallate (EGCG) cross-linked collagen membranes, with better biological activities and enhanced mechanical properties, may promote osteoblast proliferation, but their effect on osteoblast differentiation is not very significant. Nanohydroxyapatite (nano-HA) is the main component of mineral bone, which possesses exceptional bioactivity properties including good biocompatibility, high osteoconductivity and osteoinductivity, non-immunogenicity and non-inflammatory behavior. Herein, by analyzing the physical and chemical properties as well as the effects on promoting bone regeneration, we have attempted to present a novel EGCG-modified collagen membrane with nano-HA coating, and have found evidence that the novel collagen membrane may promote bone regeneration with a better surface morphology, without destroying collagen backbone. To evaluate the surface morphologies, chemical and mechanical properties of pure collagen membranes, epigallocatechin-3-gallate (EGCG) cross-linked collagen membranes, nano-HA coated collagen membranes, nano-HA coated EGCG-collagen membranes, (ii) to evaluate the bone regeneration promoted by theses membranes. In the present study, collagen membranes were divided into 4 groups: (1) untreated collagen membranes (2) EGCG cross-linked collagen membranes (3) nano-HA modified collagen membranes (4) nano-HA modified EGCG-collagen membranes. Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to evaluate surface morphologies and chemical properties, respectively. Mechanical properties were determined by differential scanning calorimeter (DSC

  10. Investigation of corrosion and wear mechanisms in hard material-reinforced duplex steel coatings; Untersuchungen zum Korrosions- und Verschleissverhalten von hartstoffverstaerkten `Duplex`-Schutzschichten. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Bouaifi, B. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Schweisstechnik und Trennende Fertigungsverfahren; Goellner, J. [Technische Univ. Magdeburg (Germany). Inst. fuer Werkstofftechnik und Werkstoffpruefung

    1998-09-30

    The hard-material reinforced duplex steel coatings were deposited by plasma arc two-powder surfacing. By varying the angle of the hard materials feeding process, the deposition of the carbides was optimized so that they are deposited into the matrix in the trailing zone of the welding torch under conditions of very low thermal effects near the freezing point of the weld pool. Microstructural studies revealed that the deposition of the hard materials prevents devlopment of the typical, ferritic-austenitic microstructure of duplex steels. Due to a dissolution and diffusion process, the microstructure of the matrix takes up carbon and chromium or tungsten, depending on the carbide, thus enhancing the austenitic material in the microstructure. The wear behaviour of the surface deposits was found to be very good, wear being reduced by a factor of 6, irrespective of the type of carbide. The friction-affected surfaces showed no dissolving effects or cracking. The corrosion behaviour in sulfuric acid is also good. The welded deposits exhibited the typical behaviour of a passive material. Wear mechanisms slightly reduce the resistance. The behaviour of various specimens in artificial seawater could be distinctly assessed. Small grain fractions and pre-heating temperatures of 100 C have a beneficial effect on the corrosion resistance. The technique recommends itself for applications such as coatings for baffle plates used in flue gas desulfurisation, pipes, pump components, flanges or nozzles, or for recurrent coating of system components affected by abrasive corrosion. (orig./CB) [Deutsch] Zur Herstellung hartstoffverstaerkter Duplex-Beschichtungen wurde das Plasma-Zwei-Pulver-Auftragschweissverfahren verwendet. Hierbei wurde durch Variation des Zufuhrwinkels der Hartstoffe der Einbringungsort der Karbide optimiert, so dass diese im Nachlauf des Schweissbrenners mit sehr geringer thermischer Beeinflussung im erstarrungsnahen Schmelzbadbereich in die Matrix eingelagert

  11. Experimental Researches Tribological Properties of Hard-Alloy Blades With a Vacuum-Plasma Coating in the Chipboards Milling Process

    Directory of Open Access Journals (Sweden)

    Pavel Viktorovič Rudak

    2015-01-01

    Full Text Available While developing effective ion-plasma coatings compositions of woodcutting tools special conditions of its use should be taken into account particularly the force rate acting on the cutting wedge. With the penetration of the blade into the wood material normal pressure and friction appear on the connection surface. For the analysis of the cutting processes the connection surface can be divided into several zones. The cutters with vacuum-plasma coatings based on TiN are characterized by a lower coefficient of friction in comparison to uncoated cutters in real conditions. The developed technique of tribotechnical tool tests of milling woodchip board is of great importance to establish the regularities of chip formation, chips movement and dust in the timber cutting areas as well as wood materials at milling in a wide parameter range of cutting conditions, for the development of methods and devices of chips and dust suppression.

  12. Technology Exploitation/Exploration/Examination Report (TeX3): Adaptive Self-Lubricating Nanoporous Hard Coatings

    Science.gov (United States)

    2008-04-01

    tribological measurements were made, including friction coefficient and wear depths and rates of the coatings deposited on 304 stainless steel using a... stainless - steel dc dual magnetron sputter deposition system with a base pressure of 1.3×10-7 Pa (1×10-9 Torr). Water-cooled 5-cm-diameter Cr and Ag...illustrated schematically in Figure 2. The substrates consist of metallographically polished 304 stainless steel and Si(001) wafers that were cleaned with

  13. Detection of thermally grown oxides in thermal barrier coatings by nondestructive evaluation

    Science.gov (United States)

    Fahr, A.; Rogé, B.; Thornton, J.

    2006-03-01

    The thermal-barrier coatings (TBC) sprayed on hot-section components of aircraft turbine engines commonly consist of a partially stabilized zirconia top-coat and an intermediate bond-coat applied on the metallic substrate. The bond-coat is made of an aluminide alloy that at high engine temperatures forms thermally grown oxides (TGO). Although formation of a thin layer of aluminum oxide at the interface between the ceramic top-coat and the bond-coat has the beneficial effect of protecting the metallic substrate from hot gases, oxide formation at splat boundaries or pores within the bond-coat is a source of weakness. In this study, plasma-sprayed TBC specimens are manufactured from two types of bond-coat powders and exposed to elevated temperatures to form oxides at the ceramic-bond-coat boundary and within the bond-coat. The specimens are then tested using nondestructive evaluation (NDE) and destructive metallography and compared with the as-manufactured samples. The objective is to determine if NDE can identify the oxidation within the bond-coat and give indication of its severity. While ultrasonic testing can provide some indication of the degree of bond-coat oxidation, the eddy current (EC) technique clearly identifies severe oxide formation within the bond-coat. Imaging of the EC signals as the function of probe location provides information on the spatial variations in the degree of oxidation, and thereby identifies which components or areas are prone to premature damage.

  14. Experimental and numerical investigations on the temperature distribution in PVD AlTiN coated and uncoated Al2O3/TiCN mixed ceramic cutting tools in hard turning of AISI 52100 steel

    Science.gov (United States)

    Sateesh Kumar, Ch; Patel, Saroj Kumar; Das, Anshuman

    2018-03-01

    Temperature generation in cutting tools is one of the major causes of tool failure especially during hard machining where machining forces are quite high resulting in elevated temperatures. Thus, the present work investigates the temperature generation during hard machining of AISI 52100 steel (62 HRC hardness) with uncoated and PVD AlTiN coated Al2O3/TiCN mixed ceramic cutting tools. The experiments were performed on a heavy duty lathe machine with both coated and uncoated cutting tools under dry cutting environment. The temperature of the cutting zone was measured using an infrared thermometer and a finite element model has been adopted to predict the temperature distribution in cutting tools during machining for comparative assessment with the measured temperature. The experimental and numerical results revealed a significant reduction of cutting zone temperature during machining with PVD AlTiN coated cutting tools when compared to uncoated cutting tools during each experimental run. The main reason for decrease in temperature for AlTiN coated tools is the lower coefficient of friction offered by the coating material which allows the free flow of the chips on the rake surface when compared with uncoated cutting tools. Further, the superior wear behaviour of AlTiN coating resulted in reduction of cutting temperature.

  15. Metallographic techniques for evaluation of thermal barrier coatings

    Science.gov (United States)

    Brindley, William J.; Leonhardt, Todd A.

    1990-01-01

    The performance of ceramic thermal barrier coatings is strongly dependent on the amount and shape of the porosity in the coating. Current metallographic techniques do not provide polished surfaces that are adequate for a repeatable interpretation of the coating structures. A technique recently developed at NASA-Lewis for preparation of thermal barrier coating sections combines epoxy impregnation, careful sectioning and polishing, and interference layering to provide previously unobtainable information on processing-induced porosity. In fact, increased contrast and less ambiguous structure developed by the method make automatic quantitative metallography a viable option for characterizing thermal barrier coating structures.

  16. Evaluation of Erosion Resistance of Advanced Turbine Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dongming; Kuczmarski, Maria A.; Miller, Robert A.; Cuy, Michael D.

    2007-01-01

    The erosion resistant turbine thermal barrier coating system is critical to aircraft engine performance and durability. By demonstrating advanced turbine material testing capabilities, we will be able to facilitate the critical turbine coating and subcomponent development and help establish advanced erosion-resistant turbine airfoil thermal barrier coatings design tools. The objective of this work is to determine erosion resistance of advanced thermal barrier coating systems under simulated engine erosion and/or thermal gradient environments, validating advanced turbine airfoil thermal barrier coating systems based on nano-tetragonal phase toughening design approaches.

  17. Work Hard / Play Hard

    OpenAIRE

    Burrows, J.; Johnson, V.; Henckel, D.

    2016-01-01

    Work Hard / Play Hard was a participatory performance/workshop or CPD experience hosted by interdisciplinary arts atelier WeAreCodeX, in association with AntiUniversity.org. As a socially/economically engaged arts practice, Work Hard / Play Hard challenged employees/players to get playful, or go to work. 'The game changes you, you never change the game'. Employee PLAYER A 'The faster the better.' Employer PLAYER B

  18. Ultra-hard AlMgB14 coatings fabricated by RF magnetron sputtering from a stoichiometric target

    Science.gov (United States)

    Grishin, A. M.; Khartsev, S. I.; Böhlmark, J.; Ahlgren, M.

    2015-01-01

    For the first time hard aluminum magnesium boride films were fabricated by RF magnetron sputtering from a single stoichiometric ceramic AlMgB14 target. Optimized processing conditions (substrate temperature, target sputtering power and target-to-substrate distance) enable fabrication of stoichiometric in-depth compositionally homogeneous films with the peak values of nanohardness 88 GPa and Young's modulus 517 GPa at the penetration depth of 26 nm and, respectively, 35 and 275 GPa at 200 nm depth in 2 μm thick film.

  19. Evaluation of Surface Characteristics of Denture Base Using Organic-Inorganic Hybrid Coating: An SEM Study.

    Science.gov (United States)

    Aa, Jafari; Mh, Lotfi-Kamran; M, Ghafoorzadeh; Sm, Shaddel

    2017-06-01

    Despite the numerous positive features of acrylic denture base, there are a number of undeniable associated disadvantages. The properties of denture base have been improved through various interventions including application of different types of filler and coatings. This study aimed to evaluate the surface roughness, thickness and coating quality of organic-inorganic coating on the denture base through scanning electron microscopy. Moreover, the colour change was evaluated visually. The organic-inorganic hybrid coatings were prepared. Acrylic discs of 10×10 mm were fabricated. The test discs were dipped in the hybrid coating and cured. In order to evaluate the surface roughness and coating thickness, the surface and cross-section of the samples in both coated and control groups were subjected to scanning electron microscopy. The colour change and transparency were visually evaluated with naked eyes. The data were statistically analyzed by student's t test. The hybrid materials perfectly covered all the surfaces of acrylic resin and established proper thickness. The coated group seemed smoother and flatter than the control group; however, the difference was not statistically significant ( for all parameters p > 0.05). It was quite a thin coating and no perceptible colour change was observed. The hybrid coating maintained good binding, caused no noticeable discoloration, and thoroughly covered the acrylic resin surface with uniform delicate thickness. It also slightly improved the acrylic resin surface roughness.

  20. Experimental Evaluation of Polyester and Epoxy–Polyester Powder Coatings in Aggressive Media

    Directory of Open Access Journals (Sweden)

    Ivan Stojanović

    2018-03-01

    Full Text Available Protective coatings are the most widely used corrosion protection method for construction materials in different environmental conditions. They isolate metals from aggressive media, making the structure more durable. Today, alongside good anti-corrosive properties, coatings need to be safe for the environment and harmless to those who apply them. The high volatile organic compound (VOC content in conventional solvent-borne coatings presents a huge ecological problem. A solution for indispensable solvent emission reduction is the application of powder coatings. This study evaluates the corrosion performance and surface morphology of polyester and epoxy–polyester powder coatings. Electrochemical impedance spectroscopy (EIS, open circuit potential (OCP measurement, salt spray chamber and humidity chamber testing followed by adhesion testing were used to investigate the protective properties of powder coatings. Scanning electron microscope (SEM with energy-dispersive X-ray spectroscopy (EDX was used to analyse the surface morphology and chemical composition, whereas the microstructure and coating uniformity were determined by optical microscope examination. The research revealed a negative influence of coating surface texture on coating thickness and consequently a lack of barrier and adhesion properties. The epoxy–polyester powder coating showed a better performance than the polyester coating. All tested coatings showed uniform structure.

  1. Evaluation of human muscle hardness after dynamic exercise with ultrasound real-time tissue elastography: A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Yanagisawa, O., E-mail: o.yanagisawa@aoni.waseda.jp [Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama (Japan); Niitsu, M. [Department of Radiological Science, Faculty of Health Sciences, Tokyo Metropolitan University, Arakawa-ku, Tokyo (Japan); Kurihara, T. [Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga (Japan); Fukubayashi, T. [Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama (Japan)

    2011-09-15

    Aim: To assess the feasibility of ultrasound real-time tissue elastography (RTE) for measuring exercise-induced changes in muscle hardness and to compare the findings of RTE with those of a tissue hardness meter for semi-quantitative assessment of the hardness of exercised muscles. Materials and methods: Nine male participants performed an arm-curl exercise. RTE measurements were performed by manually applying repetitive compression with the transducer on the scan position before exercise, immediately after exercise, and at 30 min after exercise; strain ratios between muscle and a reference material (hydrogel) were calculated (muscle strain/material strain). A tissue hardness meter was also used to evaluate muscle hardness. The intraclass correlation coefficients (ICCs) for the three repeated measurements at each measurement time were calculated to evaluate the intra-observer reproducibility of each technique. Results: Immediately after exercise, the strain ratio and the value obtained using the tissue hardness meter significantly decreased (from 1.65 to 1.35) and increased (from 51.8 to 54.3), respectively. Both parameters returned to their pre-exercise value 30 min after exercise. The ICCs of the RTE (and the ICCs of the muscle hardness meter) were 0.971 (0.816) before exercise, 0.939 (0.776) immediately after exercise, and 0.959 (0.882) at 30 min after exercise. Conclusion: Similar to the muscle hardness meter, RTE revealed the exercise-induced changes of muscle hardness semi-quantitatively. The intra-observer reproducibility of RTE was very high at each measurement time. These findings suggest that RTE is a clinically useful technique for assessing hardness of specific exercised muscles.

  2. Evaluation of human muscle hardness after dynamic exercise with ultrasound real-time tissue elastography: A feasibility study

    International Nuclear Information System (INIS)

    Yanagisawa, O.; Niitsu, M.; Kurihara, T.; Fukubayashi, T.

    2011-01-01

    Aim: To assess the feasibility of ultrasound real-time tissue elastography (RTE) for measuring exercise-induced changes in muscle hardness and to compare the findings of RTE with those of a tissue hardness meter for semi-quantitative assessment of the hardness of exercised muscles. Materials and methods: Nine male participants performed an arm-curl exercise. RTE measurements were performed by manually applying repetitive compression with the transducer on the scan position before exercise, immediately after exercise, and at 30 min after exercise; strain ratios between muscle and a reference material (hydrogel) were calculated (muscle strain/material strain). A tissue hardness meter was also used to evaluate muscle hardness. The intraclass correlation coefficients (ICCs) for the three repeated measurements at each measurement time were calculated to evaluate the intra-observer reproducibility of each technique. Results: Immediately after exercise, the strain ratio and the value obtained using the tissue hardness meter significantly decreased (from 1.65 to 1.35) and increased (from 51.8 to 54.3), respectively. Both parameters returned to their pre-exercise value 30 min after exercise. The ICCs of the RTE (and the ICCs of the muscle hardness meter) were 0.971 (0.816) before exercise, 0.939 (0.776) immediately after exercise, and 0.959 (0.882) at 30 min after exercise. Conclusion: Similar to the muscle hardness meter, RTE revealed the exercise-induced changes of muscle hardness semi-quantitatively. The intra-observer reproducibility of RTE was very high at each measurement time. These findings suggest that RTE is a clinically useful technique for assessing hardness of specific exercised muscles.

  3. Evaluation of coat uniformity and taste-masking efficiency of irregular-shaped drug particles coated in a modified tangential spray fluidized bed processor.

    Science.gov (United States)

    Xu, Min; Heng, Paul Wan Sia; Liew, Celine Valeria

    2015-01-01

    To explore the feasibility of coating irregular-shaped drug particles in a modified tangential spray fluidized bed processor (FS processor) and evaluate the coated particles for their coat uniformity and taste-masking efficiency. Paracetamol particles were coated to 20%, w/w weight gain using a taste-masking polymer insoluble in neutral and basic pH but soluble in acidic pH. In-process samples (5, 10 and 15%, w/w coat) and the resultant coated particles (20%, w/w coat) were collected to monitor the changes in their physicochemical attributes. After coating to 20%, w/w coat weight gain, the usable yield was 81% with minimal agglomeration (coat compared with the uncoated particles. A 15%, w/w coat was optimal for inhibiting drug release in salivary pH with subsequent fast dissolution in simulated gastric pH. The FS processor shows promise for direct coating of irregular-shaped drug particles with wide size distribution. The coated particles with 15% coat were sufficiently taste masked and could be useful for further application in orally disintegrating tablet platforms.

  4. Novel nanocomposite coating for dental implant applications in vitro and in vivo evaluation.

    Science.gov (United States)

    Mehdikhani-Nahrkhalaji, M; Fathi, M H; Mortazavi, V; Mousavi, S B; Hashemi-Beni, B; Razavi, S M

    2012-02-01

    This study aimed at preparation and in vitro and in vivo evaluation of novel bioactive, biodegradable, and antibacterial nanocomposite coating for the improvement of stem cells attachment and antibacterial activity as a candidate for dental implant applications. Poly (lactide-co-glycolide)/bioactive glass/hydroxyapatite (PBGHA) nanocomposite coating was prepared via solvent casting process. The nanoparticle amounts of 10, 15, and 20 weight percent (wt%) were chosen in order to determine the optimum amount of nanoparticles suitable for preparing an uniform coating. Bioactivity and degradation of the coating with an optimum amount of nanoparticles were evaluated by immersing the prepared samples in simulated body fluid and phosphate buffer saline (PBS), respectively. The effect of nanocomposite coating on the attachment and viability of human adipose-derived stem cells (hASCs) was investigated. Kirschner wires (K-wires) of stainless steel were coated with the PBGHA nanocomposite coating, and mechanical stability of the coating was studied during intramedullary implantation into rabbit tibiae. The results showed that using 10 wt% nanoparticles (5 wt% HA and 5 wt% BG) in the nanocomposite could provide the desired uniform coating. The study of in vitro bioactivity showed rapid formation of bone-like apatite on the PBGHA coating. It was degraded considerably after about 60 days of immersion in PBS. The hASCs showed excellent attachment and viability on the coating. PBGHA coating remained stable on the K-wires with a minimum of 96% of the original coating mass. It was concluded that PBGHA nanocomposite coating provides an ideal surface for the stem cells attachment and viability. In addition, it could induce antibacterial activity, simultaneously.

  5. Evaluation of dynamic characteristics of hard rock based on numerical simulations of in situ rock tests

    International Nuclear Information System (INIS)

    Yamagami, Yuya; Ikusada, Koji; Jiang, Yujing

    2009-01-01

    In situ rock tests of hard rock of conglomerate in which discontinuities in high angle are dominant were conducted. In this study, in order to confirm the validity of the test results and the test condition, and in order to elucidate the deformation behaviour and the mechanism of shear strength of the rock mass, the numerical simulations of the in situ rock tests by using distinct element method were performed. As a result, it was clarified that the behaviour of the rock mass strongly depends on both geometrical distribution of discontinuities and those mechanical properties. It is thought that a series of evaluation processes showed in this study contribute to improve the reliability of the dynamic characteristic evaluation of the rock mass. (author)

  6. The Method of Validity Evaluation of Hard Coal Excavation in Residual Seam Parts

    Science.gov (United States)

    Wodarski, Krzysztof; Bijańska, Jolanta; Gumiński, Adam

    2017-12-01

    The excavation of residual seam parts should be justified by positive assessment of the purposefulness, technical feasibility and economic effectiveness. The results of the profitability evaluation are crucial in a decision making process. The excavation of residual seam parts, even if it is possible from a technical point of view, should not be implemented if it is economically inefficient or when accompanied by a very high risk of non-recovery of invested capital resources. The article presents the evaluation method of possibilities of excavating hard coal from residual seam parts, and the example of its use in one of collieries in the Upper Silesian Coal Basin. Working in line with the developed method, allows to indicate the variant of residual seam part exploitation, which is feasible to implement from a technical point of view, and which is characterized by the highest economic effectiveness and lowest risk.

  7. THE STRUCTURE AND PROPERTIES OF COMPOSITE LASER CLAD COATINGS WITH Ni BASED MATRIX WITH WC PARTICLES

    Directory of Open Access Journals (Sweden)

    Zita Iždinská

    2010-09-01

    Full Text Available In this work, the influence of the processing conditions on the microstructure and abrasive wear behavior of composite laser clad coatings with Ni based matrix reinforced with 50% WC particles is analyzed. Composite powder was applied in the form of coatings onto a mild steel substrate (Fe–0.17% C by different laser powers and cladding speeds. The microstructure of the coatings was analyzed by scanning electron microscopy (SEM. Tribological properties of coatings were evaluated by pin-on-disc wear test. It appeared that the hardness of the matrix of composite coatings decreases with increasing cladding speed. However, wear resistance of composite coatings with decreasing hardness of Ni based matrix increases. Significantly enhanced wear resistance of WC composite coatings in comparison with Ni based coatings is attributed to the hard phase structures in composite coatings.

  8. Comparative evaluation of coating techniques for the corrosion protection of disposal container for spent nuclear fuel

    International Nuclear Information System (INIS)

    Chun, Kwan Sik; Kim, Sung Soo; Park, Chong Mook; Choi, Jong Won

    2005-02-01

    To propose a suitable coating technique to prevent corrosion on metal or metal alloys of a waste container to be used for the disposal of spent nuclear fuel, several methods related to spray coating and vapor deposition techniques have been comparatively evaluated, based on some major factors recommended. From these comparative results, it can be suggested that the best coating methods among the existing techniques in Korea would be HVOF and low pressure plasma spray. Even though the surface of the container coated by these methods would be coated, pores could be remained in the coated film. And therefore post-treatment methods for eliminating the pores have been briefly introduced to keep the life time of the container. The other techniques, the cold spray and hollow cathode discharge, may become excellent coating methods in the future if they are extensively researched to apply for coating on the container. An optimal process among the recommended methods should be selected by considering the state of container, such as an empty or a loaded container, and also related coating materials. For the support to this, the characteristics of the coating materials and the coated films and the durability of this film under a repository condition should be analyzed in detail

  9. Evaluation of thermal aging effect on primary pipe material in nuclear power plant by micro hardness test method

    International Nuclear Information System (INIS)

    Xue Fei; Yu Weiwei; Wang Zhaoxi; Ma Qinzheng; Liu Wei

    2012-01-01

    The investigation was carried out on the changes in mechanical properties of the primary pipe material Z3CN20.09M after 10000 h aging at 400℃ by using micro- Vickers and impact testing machine. The results show that the impact energy of testing material decreases. However, the micro-Vickers hardness of ferrite phase and austenite phase which constitute the testing material increase and keep constant, respectively. The intrinsic relations were analyzed between the micro-Vickers hardness and the impact energy to make an attempt to present the micro-Vickers hardness measurement as a method applicable to evaluating the thermal aging of the primary pipe material. (authors)

  10. Life evaluation of FR-CV cable on thermal-radiation combined aging by micro-hardness

    International Nuclear Information System (INIS)

    Sugiyama, Masahiko; Ogata, Akimasa; Nitta, Makoto; Tani, Tsuneo; Yagi, Toshiaki; Seguchi, Tadao.

    1996-01-01

    For the evaluation of cable life for the application to nuclear facilities, the accelerated test was conducted by the combination of radiation and thermal oxidation. The degradation of FR-CV cable by the aging was monitored by tensile test, micro-hardness test, and gel-fraction measurement. The micro-hardness increased with the progress of degradation and related well with decrease of ultimate elongation of the sheath material, and was also reflected by the loss of plasticizer. The micro-hardness technique has a possibility to detect the degradation of cable as a non-destructive detector. (author)

  11. A field evaluation of coated urea with biodegradable materials and ...

    African Journals Online (AJOL)

    ajl yemi

    2011-12-28

    Dec 28, 2011 ... Urease inhibitor and biodegradable polymer coatings are two most suitable startegies to increase urea fertilizer efficiency. Coating of urea with selected inhibitors can increase the crop production by slowing down the hydrolysis process of urea in the soil. For this purpose, a field experiment was conducted ...

  12. Development of a Laboratory Test Procedure to Evaluate Tack Coat Performance

    OpenAIRE

    YILDIRIM, Yetkin; SMIT, André de Fortier; KORKMAZ, Armagan

    2014-01-01

    A laboratory testing procedure is presented, the results of which may be used for determining the best combination of tack coat type, mixture type, and application rate to be applied in the field for optimum performance. Tack coat related performance results were determined from Hamburg wheel tracking and simple shear tests on laboratory prepared specimens. This study was undertaken to evaluate the shear strength performance of tack coats under laboratory-controlled conditions. The ...

  13. Swedish Hard Rock Laboratory first evaluation of preinvestigations 1986-87 and target area characterization

    International Nuclear Information System (INIS)

    Gustafson, G.; Stanfors, R.; Wikberg, P.

    1988-06-01

    SKB plans to site an underground research laboratory in the Simpevarp area. A regional survey started in 1986 and an extensive programme for geology, geohydrology and hydrochemistry was carried through. This report gives an evaluation of all available data gathered from the start of the project up to the drilling of core boreholes in some target areas in the autumn of 1987. A descriptive geological-tectonic model on a regional scale is presented that is intended to constitute a basis for the hydrogeological modelling work. Preliminary rock mass descriptions are also presented on a more detailed scale for some minor parts of the area. It is recommended that the island Aespoe is the principal target area for the continued work on the Swedish Hard Rock Laboratory. (orig.)

  14. Evaluation of a Low Temperature Cure Powder Coating

    Science.gov (United States)

    2008-05-01

    4”x6”x1/4” Al 2024-T3 panels were chromate conversion coated by NDCEE per MIL-DTL-5514F Type 1 Class A  Reserved for LTCPC  27 – 4”x6”x1/4” Al...2024-T3 panels were chromate conversion coated by FRC Southeast per MIL-DTL- 5514F Type 1 Class A  Reserved for baseline coating JSEM - May...conducted under contract W74V8H- 04-D-0005 Task 427. DISCLAIMER: The contents of this document are not to be used for advertising , publication, or

  15. Evaluation of electrodeposited Mn-Co protective coatings on Crofer 22 APU steel

    DEFF Research Database (Denmark)

    Molin, Sebastian

    2018-01-01

    Interconnects used in Solid Oxide Cells stacks require protective coatings to lower their parabolic rate constant and block chromium evaporation (on the air side). In this work four different protective coatings on steel are evaluated for their high temperature corrosion resistance and electrical...... conductivity. A commercial electroplating process was used for the preparation of coatings with different Mn/Co ratios on Crofer 22 APU steel. Oxidation of samples was performed in air at 800°C for 1000 hours. Postmortem analysis of the coated samples was performed by scanning electron microscopy and x......-ray diffractomettry. Based on the results, influence of the Co/Mn ratio on the resulting corrosion properties are discussed. Parabolic rate constant of the coated samples is the lowest for the MnCo sample, whereas electrical resistance is the lowest for the Co sample, which has a corrosion rate similar to the not-coated...

  16. Electrochemical Evaluation of Corrosion Inhibiting Layers Formed in a Defect from Lithium-Leaching Organic Coatings

    NARCIS (Netherlands)

    Visser, P.; Meeusen, M.; Gonzalez Garcia, Y.; Terryn, H.A.; Mol, J.M.C.

    2017-01-01

    This work presents the electrochemical evaluation of protective layers generated in a coating defect from lithium-leaching organic coatings on AA2024-T3 aluminum alloys as a function of neutral salt spray exposure time. Electrochemical impedance spectroscopy was used to study the electrochemical

  17. Scope of work for evaluating the mechanical performance of EPR first wall coatings

    International Nuclear Information System (INIS)

    Jones, W.B.; Van Den Avyle, J.A.

    1978-01-01

    An outline is presented for a proposed scope of work to evaluate the mechanical performance of candidate first wall coatings for a Tokamak-type fusion reactor. The goal of the overall program is to provide an adequate coating material and recoating process which can be manufactured by currently available vendors

  18. Tribological Evaluation of Magnetron-Sputtered Coating for Military Applications

    National Research Council Canada - National Science Library

    Beatty, John

    1999-01-01

    .... In our ongoing study, a number of different coatings were applied to 52100 bearing steel, 4340 steel, Inconel 718, and Ti-6Al-4V to improve wear characteristics, corrosion resistance, and rolling...

  19. Design and implementation of reliability evaluation of SAS hard disk based on RAID card

    Science.gov (United States)

    Ren, Shaohua; Han, Sen

    2015-10-01

    Because of the huge advantage of RAID technology in storage, it has been widely used. However, the question associated with this technology is that the hard disk based on the RAID card can not be queried by Operating System. Therefore how to read the self-information and log data of hard disk has been a problem, while this data is necessary for reliability test of hard disk. In traditional way, this information can be read just suitable for SATA hard disk, but not for SAS hard disk. In this paper, we provide a method by using LSI RAID card's Application Program Interface, communicating with RAID card and analyzing the feedback data to solve the problem. Then we will get the necessary information to assess the SAS hard disk.

  20. On the application of response surface methodology for predicting and optimizing surface roughness and cutting forces in hard turning by PVD coated insert

    Directory of Open Access Journals (Sweden)

    Hessainia Zahia

    2015-04-01

    Full Text Available This paper focuses on the exploitation of the response surface methodology (RSM to determine optimum cutting conditions leading to minimum surface roughness and cutting force components. The technique of RSM helps to create an efficient statistical model for studying the evolution of surface roughness and cutting forces according to cutting parameters: cutting speed, feed rate and depth of cut. For this purpose, turning tests of hardened steel alloy (AISI 4140 (56 HRC were carried out using PVD – coated ceramic insert under different cutting conditions. The equations of surface roughness and cutting forces were achieved by using the experimental data and the technique of the analysis of variance (ANOVA. The obtained results are presented in terms of mean values and confidence levels. It is shown that feed rate and depth of cut are the most influential factors on surface roughness and cutting forces, respectively. In addition, it is underlined that the surface roughness is mainly related to the cutting speed, whereas depth of cut has the greatest effect on the evolution of cutting forces. The optimal machining parameters obtained in this study represent reductions about 6.88%, 3.65%, 19.05% in cutting force components (Fa, Fr, Ft, respectively. The latters are compared with the results of initial cutting parameters for machining AISI 4140 steel in the hard turning process.

  1. Technologies for Nondestructive Evaluation of Surfaces and Thin Coatings

    Science.gov (United States)

    1999-01-01

    The effort included in this project included several related activities encompassing basic understanding, technological development, customer identification and commercial transfer of several methodologies for nondestructive evaluation of surfaces and thin surface coatings. Consistent with the academic environment, students were involved in the effort working with established investigators to further their training, provide a nucleus of experienced practitioners in the new technologies during their industrial introduction, and utilize their talents for project goals. As will be seen in various portions of the report, some of the effort has led to commercialization. This process has spawned other efforts related to this project which are supported from outside sources. These activities are occupying the efforts of some of the people who were previously supported within this grant and its predecessors. The most advanced of the supported technologies is thermography, for which the previous joint efforts of the investigators and NASA researchers have developed several techniques for extending the utility of straight thermographic inspection by producing methods of interpretation and analysis accessible to automatic image processing with computer data analysis. The effort reported for this technology has been to introduce the techniques to new user communities, who are then be able to add to the effective uses of existing products with only slight development work. In a related development, analysis of a thermal measurement situation in past efforts led to a new insight into the behavior of simple temperature probes. This insight, previously reported to the narrow community in which the particular measurement was made, was reported to the community of generic temperature measurement experts this year. In addition to the propagation of mature thermographic techniques, the development of a thermoelastic imaging system has been an important related development. Part of the

  2. Hard electronics; Hard electronics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Hard material technologies were surveyed to establish the hard electronic technology which offers superior characteristics under hard operational or environmental conditions as compared with conventional Si devices. The following technologies were separately surveyed: (1) The device and integration technologies of wide gap hard semiconductors such as SiC, diamond and nitride, (2) The technology of hard semiconductor devices for vacuum micro- electronics technology, and (3) The technology of hard new material devices for oxides. The formation technology of oxide thin films made remarkable progress after discovery of oxide superconductor materials, resulting in development of an atomic layer growth method and mist deposition method. This leading research is expected to solve such issues difficult to be easily realized by current Si technology as high-power, high-frequency and low-loss devices in power electronics, high temperature-proof and radiation-proof devices in ultimate electronics, and high-speed and dense- integrated devices in information electronics. 432 refs., 136 figs., 15 tabs.

  3. Validation of HVOF Thermal Spray Coatings as a Replacement for Hard Chrome Plating on Hydraulic/Pneumatic Actuators

    Science.gov (United States)

    2007-12-01

    Projects Agency (DARPA). The program evaluated HVOF, physical vapor deposition (PVD) and laser cladding , and concluded that HVOF was the best overall...components such as titanium flap tracks. 5 2.0 TECHNOLOGY DESCRIPTION 2.1 TECHNOLOGY DEVELOPMENT AND APPLICATION Technology background and...theory of operation: High-velocity oxygen-fuel (HVOF) is a standard commercial thermal spray process in which a powder of the material to be sprayed

  4. Quantifying Pharmaceutical Film Coating with Optical Coherence Tomography and Terahertz Pulsed Imaging: An Evaluation

    Science.gov (United States)

    Lin, Hungyen; Dong, Yue; Shen, Yaochun; Zeitler, J Axel

    2015-01-01

    Spectral domain optical coherence tomography (OCT) has recently attracted a lot of interest in the pharmaceutical industry as a fast and non-destructive modality for quantification of thin film coatings that cannot easily be resolved with other techniques. Because of the relative infancy of this technique, much of the research to date has focused on developing the in-line measurement technique for assessing film coating thickness. To better assess OCT for pharmaceutical coating quantification, this paper evaluates tablets with a range of film coating thickness measured using OCT and terahertz pulsed imaging (TPI) in an off-line setting. In order to facilitate automated coating quantification for film coating thickness in the range of 30–200 μm, an algorithm that uses wavelet denoising and a tailored peak finding method is proposed to analyse each of the acquired A-scan. Results obtained from running the algorithm reveal an increasing disparity between the TPI and OCT measured intra-tablet variability when film coating thickness exceeds 100 μm. The finding further confirms that OCT is a suitable modality for characterising pharmaceutical dosage forms with thin film coatings, whereas TPI is well suited for thick coatings. © 2015 The Authors. Journal of Pharmaceutical Sciences published by Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:3377–3385, 2015 PMID:26284354

  5. Thermal spray deposition and evaluation of low-Z coatings

    International Nuclear Information System (INIS)

    Seals, R.D.; Swindeman, C.J.; White, R.L.

    1996-01-01

    Thermally sprayed low-Z coatings of B 4 C on Al substrates were investigated as candidate materials for first-wall reactor protective surfaces. Comparisons were made to thermally sprayed coatings of B, MgAl 2 O 4 , Al 2 O 3 , and composites. Graded bond layers were applied to mitigate coefficient of thermal expansion mismatch. Microstructures, thermal diffusivity before and after thermal shock loading, steel ball impact resistance, CO 2 pellet cleaning and erosion tolerance, phase content, stoichiometry by Rutherford backscattering spectroscopy, and relative tensile strengths were measured

  6. Non-Sacrificial, Anti-Graffiti Coating 2009 Evaluation

    Science.gov (United States)

    2010-04-01

    Graffiti eradication is a problem for the Nevada Department of Transportation (NDOT). Over 12,000 man-hours are spent on graffiti eradication each year. One recognized graffiti abatement method is the use of non-sacrificial, anti-graffiti coating. ND...

  7. Evaluation of bond strength of isothermally aged plasma sprayed thermal barrier coating

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae Jin; Lee, Dong Hoon; Koo, Jae Mean; Song, Sung Jin; Seok, Chang Sung [Sungkyunkwan University, Suwon (Korea, Republic of); Kim, Mun Young [Korea Plant Service and Engineering Co., Ltd., Seongnam (Korea, Republic of)

    2008-07-15

    In this study, disk type of thermal barrier coating system for gas turbine blade was isothermally aged in the furnace changing exposure time and temperature. For each aging condition, bond tests for three samples were conducted for evaluating degradation of adhesive or cohesive strength of thermal barrier coating system. For as-sprayed condition, the location of fracture in the bond test was in the middle of epoxy which have bond strength of 57 MPa. As specimens are degraded by thermal aging, bond strength gradually decreased and the location of failure was also changed from within top coat at the earlier stage of thermal aging to the interface between top coat and TGO at the later stage due to the delamination in the coating.

  8. Evaluation of Protective Ability of High Solid Novolac Clear Coatings Through Electrochemical Techniques

    International Nuclear Information System (INIS)

    Ramesh, D.; Shakkthivel, P.; Manickam, A. Susai; Kalpana, A.; Vasudevan, T.

    2006-01-01

    Solvent free high solid coatings are increasingly used as they posses number of advantages such as, lower cost per unit film thickness, better performance and eco-friendliness. In the present study polymeric film-forming materials such as aniline-novolac (ANS), cresol-novolac (CNS) and acrylic copolymer blended cresol-novolac (ACNS) coating materials have been prepared. The corrosion resistance properties of the prepared high solid coating materials have been evaluated through potential-time, potentiodynamic polarization and electrochemical impedance studies (EIS). Among the three coating systems, cresol-novolac polymer coated substrates offer better corrosion resistance property and the order of the performance was found as CNS > ACNS > ANS. We can recommend these systems for use in automobile applications

  9. Evaluation of properties and thermal stress field for thermal barrier coatings

    Institute of Scientific and Technical Information of China (English)

    王良; 齐红宇; 杨晓光; 李旭

    2008-01-01

    In order to get thermal stress field of the hot section with thermal barrier coating (TBCs), the thermal conductivity and elastic modulus of top-coat are the physical key properties. The porosity of top-coat was tested and evaluated under different high temperatures. The relationship between the microstructure (porosity of top-coat) and properties of TBCs were analyzed to predict the thermal properties of ceramic top-coat, such as thermal conductivity and elastic modulus. The temperature and stress field of the vane with TBCs were simulated using two sets of thermal conductivity data and elastic modulus, which are from literatures and this work, respectively. The results show that the temperature and stress distributions change with thermal conductivity and elastic modulus. The differences of maximum temperatures and stress are 6.5% and 8.0%, respectively.

  10. Economic evaluation of five curing processes for wood coatings

    International Nuclear Information System (INIS)

    Martinez M, I.

    1996-01-01

    In this work we study the economic feasibility of five methods for curing coatings over sheet wood products. Each year, Mexico is producing more than 40 millions of square meters of wood panels, but the demand is of the range of 58 millions of square meters of this product. Two millions are expended after they are coated, and 38 millions without coating, they are coated artisanilly when they are used to make pieces of furniture. The technical characteristics and the costs involved in each one of five methods of curing, are described. Investments involved with each method are processed to establish: fixed costs, variable costs, equilibrium point, and others. Initial investment, coasts and revenues are processed to determine the income statement pro-form, the projected statement of change in financial position, the projected working capital, the projected balance sheet, the cash-flow, and some economical and financial indicators for each one of the five curing methods. With this information, the internal rate of return (IRR) is determined, and used to compare the economic worth of each of the five methods. The five methods are profitable, because all they have a IRR greater than the opportunity cost of capital (15%) of projects with similar characteristics. Despite, with each one of the five methods, the capital invested is recoverable, and profits can be obtained; curing by ultraviolet light or by electron beam, let recover the investment in less than two years, require fewer dollars for investment, and have a IRR of 135% and 111% respectively. Besides ultraviolet light or electron beam curing processes, pollute less with volatile solvents, use the energy efficiently, have greater production rate, and the coating obtained have better quality than with the other three methods. (Author)

  11. Primary control of upper gingiva and hard palate squamous cell carcinoma. A clinical evaluation

    International Nuclear Information System (INIS)

    Beppu, Takeshi; Mitani, Hiroki; Kawabata, Kazuyoshi

    2005-01-01

    The primary control of upper gingiva and hard palate squamous cell carcinoma was evaluated clinically. From 1985 to 1999, there were 51 cases that received definitive treatment in our hospital with a primary control rate of 70.6%. The primary control rates according to treatment modality were: 73.3% for surgery alone (69.2% for partial maxillectomy, 80% for total maxillectomy); 71.4% for definitive radiation therapy; and 68% for combined surgery and radiation therapy. The primary control rates according to the T stage were: 85.7% for T1; 60% for T2; 77.8% for T3; and 80% for T4. In general, primary control was better when the tumor was located anteriorly rather than posterolaterally in the oral cavity. Frequent recurrent sites following the operation were the infratemporal fossa and/or the pterygopalatine fossa, especially when the tumor had been located posterolaterally. In such cases, a salvage operation was often impossible, and the uncontrollable primary lesion progressed and caused death. Therefore, when the tumor is located posterolaterally, and especially if it has invaded deeply into the infratemporal fossa and the pterygopalatine fossa, it is vitally important to properly plan the surgical approach and to ensure a good visual operative field. (author)

  12. Preliminary clinical evaluation of hard- and soft-copy digitized chest radiography

    Science.gov (United States)

    Rian, Roger L.; Smerud, Michael J.; Guinn, Todd

    1994-05-01

    The digital applications in radiology are a controversial advanced which potentially will influence all areas of patient imaging. It is utilized and accepted in angiography, computed tomography, magnetic resonance, nuclear imaging and sonography. More recently Computed Radiography has gained credibility in mobile scenarios as well as specific applications from cervical spine radiography to digital fluoroscopy. Usually this acceptance is related to benefits of lesser radiation exposure or an improved presentation with an incorrect radiographic technique. One advantage of interpreting from digital information is the potential manipulation of the image presentation to the observer through windowing, leveling and edge enhancement pre and/or during image review. Additionally this digital data can be transmitted over distance and represented as hard and/or soft copy for primary or consultative review. The number and quality of the images to be viewed, the environment of the review station as well as the observer experience with conventional radiographic as well as digital image evaluation are important aspects of delivering the radiologist's product i.e. the final interpretation. This paper assesses that product, specifically addressing the question `Is the radiologist's report the same whether derived from the original analog image or from its digitized image.' The object of this study is to determine whether a digital system (3M PACS) designed for consultative viewing in a satellite department can also be used directly for primary diagnosis of conventional chest exams.

  13. Automated pharmaceutical tablet coating layer evaluation of optical coherence tomography images

    International Nuclear Information System (INIS)

    Markl, Daniel; Sacher, Stephan; Khinast, Johannes G; Hannesschläger, Günther; Leitner, Michael; Buchsbaum, Andreas

    2015-01-01

    Film coating of pharmaceutical tablets is often applied to influence the drug release behaviour. The coating characteristics such as thickness and uniformity are critical quality parameters, which need to be precisely controlled. Optical coherence tomography (OCT) shows not only high potential for off-line quality control of film-coated tablets but also for in-line monitoring of coating processes. However, an in-line quality control tool must be able to determine coating thickness measurements automatically and in real-time. This study proposes an automatic thickness evaluation algorithm for bi-convex tables, which provides about 1000 thickness measurements within 1 s. Beside the segmentation of the coating layer, optical distortions due to refraction of the beam by the air/coating interface are corrected. Moreover, during in-line monitoring the tablets might be in oblique orientation, which needs to be considered in the algorithm design. Experiments were conducted where the tablet was rotated to specified angles. Manual and automatic thickness measurements were compared for varying coating thicknesses, angles of rotations, and beam displacements (i.e. lateral displacement between successive depth scans). The automatic thickness determination algorithm provides highly accurate results up to an angle of rotation of 30°. The computation time was reduced to 0.53 s for 700 thickness measurements by introducing feasibility constraints in the algorithm. (paper)

  14. Residual stress evaluation in brittle coatings using indentation technique combined with in-situ bending

    International Nuclear Information System (INIS)

    Futakawa, Masatoshi; Steinbrech, R.W.; Tanabe, Yuji; Hara, Toshiaki

    2000-01-01

    The indentation crack length approach was adopted and further elaborated to evaluate residual stress and toughness of the brittle coatings: two kinds of glass coatings on steel. The influence of the residual stress on indentation cracking was examined in as-received coating condition and by in-situ superimposing a counteracting tensile stress. For purpose of providing reference toughness values stress-free pieces of separated coating material have also been examined. Thus results of the two complementary sets of experiments were assumed to prove self-consistently toughness and residual stress data of the coating. In particular, the in-situ bending of specimen in combination with the indentation test allowed us to vary deliberately the residual stress situation in glass coating. Thus experiments which utilized the combination of bending test and micro-indentation were introduced as a method to provide unambiguous information about residual compressive stress. Toughness and residual compressive stress of glass coatings used in this study were 0.46-0.50 MPa·m 1/2 and 94-111 MPa, respectively. Furthermore, a thermoelastic calculation of the residual compressive stress was performed and it is found that the value of residual compressive stress at coating surface of specimen was 90-102 MPa. (author)

  15. Experimental evaluation of chromium-carbide-based solid lubricant coatings for use to 760 C

    Science.gov (United States)

    Dellacorte, Christopher

    1987-01-01

    A research program is described which further developed and investigated chromium carbide based self-lubricating coatings for use to 760 C. A bonded chromium carbide was used as the base stock because of the known excellent wear resistance and the chemical stability of chromium carbide. Additives were silver and barium fluoride/calcium fluoride eutectic. The three coating components were blended in powder form, applied to stainless steel substrates by plasma spraying and then diamond ground to the desired coating thickness. A variety of coating compositions was tested to determine the coating composition which gave optimum tribological results. Coatings were tested in air, helium, and hydrogen at temperatures from 25 to 760 C. Several counterface materials were evaluated with the objective of discovering a satisfactory metal/coating sliding combination for potential applications, such as piston ring/cylinder liner couples for Stirling engines. In general, silver and fluoride additions to chromium carbide reduced the friction coefficient and increased the wear resistance relative to the unmodified coating. The lubricant additives acted synergistically in reducing friction and wear.

  16. Fluidized bed deposition and evaluation of silicon carbide coatings on microspheres

    International Nuclear Information System (INIS)

    Federer, J.I.

    1977-01-01

    The fuel element for the HTGR is an array of closely packed fuel microspheres in a carbonaceous matrix. A coating of dense silicon carbide (SiC), along with pyrocarbon layers, is deposited on the fueled microspheres to serve as a barrier against diffusion of fission products. The microspheres are coated with silicon carbide in a fluidized bed by reaction of methyltrichlorosilane (CH 3 SiCl 3 or MTS) and hydrogen at elevated temperatures. The principal variables of coating temperature and reactant gas composition (H 2 /MTS ratio) have been correlated with coating rate, morphology, stoichiometry, microstructure, and density. The optimum temperature for depositing highly dense coatings is in the range 1475 to 1675 0 C. Lower temperatures result in silicon-rich deposits, while higher temperatures may cause unacceptable porosity. The optimum H 2 /MTS ratio for highly dense coatings is 20 or more (approximately 5% MTS or less). The amount of grown-in porosity increases as the H 2 /MTS ratio decreases below 20. The requirement that the H 2 /MTS ratio be about 20 or more imposes a practical restraint on coating rate, since increasing the total flow rate would eventually expel microspheres from the coating tube. Evaluation of stoichiometry, morphology, and microstructure support the above mentioned optimum conditions of temperature and reactant gas composition. 18 figures, 3 tables

  17. Nano-hardness estimation by means of Ar+ ion etching

    International Nuclear Information System (INIS)

    Bartali, R.; Micheli, V.; Gottardi, G.; Vaccari, A.; Safeen, M.K.; Laidani, N.

    2015-01-01

    When the coatings are in nano-scale, the mechanical properties cannot be easily estimated by means of the conventional methods due to: tip shape, instrument resolution, roughness, and substrate effect. In this paper, we proposed a semi-empirical method to evaluate the mechanical properties of thin films based on the sputtering rate induced by bombardment of Ar + ion. The Ar + ion bombardment was induced by ion gun implemented in Auger electron spectroscopy (AES). This procedure has been applied on a series of coatings with different structure (carbon films) and a series of coating with a different density (ZnO thin films). The coatings were deposited on Silicon substrates by RF sputtering plasma. The results show that, as predicted by Insepov et al., there is a correlation between hardness and sputtering rate. Using reference materials and a simple power law equation the estimation of the nano-hardness using an Ar + beam is possible. - Highlights: • ZnO film and Carbon films were grown on silicon using PVD. • The growth temperature was room temperature. • The hardness of the coatings was estimated by means of nanoindentation. • Evaluation of resistance of materials to the mechanical damage induced by an Ar + ion gun (AES). • The hardness have been studied and a power law with the erosion rate has been found

  18. Evaluation of Glider Coatings Against Biofouling for Improved Flight Performance

    Science.gov (United States)

    2011-08-17

    and used to conduct assays of survivorship with approximately 100 nauplii larvae ofArtemia sp. (brine shrimp ). The larvae were exposed to the...seal (D). These coatings showed higher mortality of brine shrimp as well as 100% mortality of cypris larvae during the settlement assay which...brine shrimp compared to the glass control; however these did not inhibit settlement and were evidently not toxic to the cypris larvae . All other

  19. Development of a Nondestructive Evaluation Technique for Degraded Thermal Barrier Coatings Using Microwave

    Science.gov (United States)

    Sayar, M.; Ogawa, K.; Shoji, T.

    2008-02-01

    Thermal barrier coatings have been widely used in gas turbine engines in order to protect substrate metal alloy against high temperature and to enhance turbine efficiency. Currently, there are no reliable nondestructive techniques available to monitor TBC integrity over lifetime of the coating. Hence, to detect top coating (TC) and TGO thicknesses, a microwave nondestructive technique that utilizes a rectangular waveguide was developed. The phase of the reflection coefficient at the interface of TC and waveguide varies for different TGO and TC thicknesses. Therefore, measuring the phase of the reflection coefficient enables us to accurately calculate these thicknesses. Finally, a theoretical analysis was used to evaluate the reliability of the experimental results.

  20. Evaluation of steam corrosion and water quenching behavior of zirconium-silicide coated LWR fuel claddings

    Science.gov (United States)

    Yeom, Hwasung; Lockhart, Cody; Mariani, Robert; Xu, Peng; Corradini, Michael; Sridharan, Kumar

    2018-02-01

    This study investigates steam corrosion of bulk ZrSi2, pure Si, and zirconium-silicide coatings as well as water quenching behavior of ZrSi2 coatings to evaluate its feasibility as a potential accident-tolerant fuel cladding coating material in light water nuclear reactor. The ZrSi2 coating and Zr2Si-ZrSi2 coating were deposited on Zircaloy-4 flats, SiC flats, and cylindrical Zircaloy-4 rodlets using magnetron sputter deposition. Bulk ZrSi2 and pure Si samples showed weight loss after the corrosion test in pure steam at 400 °C and 10.3 MPa for 72 h. Silicon depletion on the ZrSi2 surface during the steam test was related to the surface recession observed in the silicon samples. ZrSi2 coating (∼3.9 μm) pre-oxidized in 700 °C air prevented substrate oxidation but thin porous ZrO2 formed on the coating. The only condition which achieved complete silicon immobilization in the oxide scale in aqueous environments was the formation of ZrSiO4 via ZrSi2 coating oxidation in 1400 °C air. In addition, ZrSi2 coatings were beneficial in enhancing quenching heat transfer - the minimum film boiling temperature increased by 6-8% in the three different environmental conditions tested. During repeated thermal cycles (water quenching from 700 °C to 85 °C for 20 s) performed as a part of quench tests, no spallation and cracking was observed and the coating prevented oxidation of the underlying Zircaloy-4 substrate.

  1. SHS合成TiC粉对铁基涂层显微组织和硬度的影响%Effect of SHS TiC Reinforced Fe on Microstructure and Hardness of Composite Coatings on Steel

    Institute of Scientific and Technical Information of China (English)

    温芳; 林涛; 刘祥庆; 郭志猛

    2011-01-01

    以钛粉、石墨粉为原料通过自蔓延高温(SHS)合成TiC,通过破碎、筛分制得不同粒度的TiC.以此TiC为硬质相、以铁基合金粉为粘结相通过真空熔覆方法,制得TiC/Fe基耐磨涂层.研究了TiC不同含量、粒度对涂层的微观组织、硬度的影响,并与添加传统微米级TiC的涂层进行了比较.结果表明:当TiC粒度一定时,随着TiC含量的增加,耐磨涂层的硬度略有增加,达到62HRC;当TiC的加入量一定时,随着TIC的粒度增大,耐磨涂层的硬度基本不变,保持在63HRC左右.在涂层组织中,SHS方法制得的硬质相TiC在涂层中分布均匀,且TiC颗粒和铁基粘结相的界面结合好,这将对涂层的耐磨性起到很好的作用.%Titanium carbide were produced by self-propagating high temperature synthesis, which were composed of titanium powder and graphite powder. Then different sizes of TiC were obtained by broken and screening in order to as a hard phase. In addition, a TiC/Fe surface composite,consising of SHS titanium carbide and cast iron ,was produced by Vacluum cladding process. The effect of different content and size of Tic particles on microstructure and hardness was studied. And the it was checked againsted the coating which was added with traditional nano Tic particles. Results show that when the quality fraction of TiC particles is constant ,the smaller the particles size,the higher hardness. The highest hardness can be reached to 62 HRC. When the size of TiC particles is unchanged, with the increase of quality fraction of TiC particles, the hardness hardly increases and maintains at ahout 63 HRC. TiC particles uniform distribute in composite coating . The composite coating and the master-steel has good interfacial boning. That is benefical to the wear resistance of coating.

  2. Evaluation of hardness and colour change of soft liners after accelerated ageing.

    Science.gov (United States)

    Mancuso, Daniela Nardi; Goiato, Marcelo Coelho; Zuccolotti, Bruna Carolina Rossatti; Moreno, Amália; dos Santos, Daniela Micheline

    2009-07-01

    Soft liners have been developed to offer comfort to denture wearers. However, this comfort is compromised when there is a change in the properties of the material, causing colour change, solubility, absorption and hardening. These characteristics can compromise the longevity of soft liners. The aim of this in vitro study was to investigate the effect of ageing on both the hardness and colour change of two soft liners following accelerated ageing. Two denture liners, one resin based (Trusoft, Bosworth, Illinois, USA) and one silicone based (Ufi Gel P, Voco GMBH, Cuxhaven, Germany), were tested in this study for both hardness (using the Shore A scale) and colour change (using the CIE L*a*b* colour scale), initially and after 1008 hours (6 weeks) of accelerated ageing. Statistical analysis was performed using the unpaired t-test with the Welch correction. These indicated that both materials increased in hardness and underwent colour change after accelerated ageing. The initial hardness of Trusoft was far lower than that of Ufi Gel P (18.2 Shore A units vs 34.8 Shore A units). However, for Trusoft the changes for both hardness (from 18.2 to 52.1 Shore A units) and colour change (16.85 on the CIE L*a*b* colour scale) were greater than those for Ufi Gel P, for which hardness changed from 34.8 to 36.5 Shore A units and the colour change was 5.19 on the CIE L*a*b* colour scale. Ufi Gel P underwent less hardness and colour change after accelerated ageing than Trusoft. On the other hand, the use of Trusoft may be preferable in cases where initial softness is a major consideration, such as when relining an immediate denture after implant surgery.

  3. Comprehensive hard materials

    CERN Document Server

    2014-01-01

    Comprehensive Hard Materials deals with the production, uses and properties of the carbides, nitrides and borides of these metals and those of titanium, as well as tools of ceramics, the superhard boron nitrides and diamond and related compounds. Articles include the technologies of powder production (including their precursor materials), milling, granulation, cold and hot compaction, sintering, hot isostatic pressing, hot-pressing, injection moulding, as well as on the coating technologies for refractory metals, hard metals and hard materials. The characterization, testing, quality assurance and applications are also covered. Comprehensive Hard Materials provides meaningful insights on materials at the leading edge of technology. It aids continued research and development of these materials and as such it is a critical information resource to academics and industry professionals facing the technological challenges of the future. Hard materials operate at the leading edge of technology, and continued res...

  4. Preparation and performance evaluation of epoxy-based heat reflective coating for the pavement

    Science.gov (United States)

    Hu, B.; Liang, Y. H.; Guo, L. Y.; Jiang, T.

    2017-04-01

    According to the basic characteristics and composition of heat-reflective coating, combining with the functional requirements of road materials, the experiment selects the epoxy resin with good wear resistance and adhesive force as a film forming material, with TiO2, SiO2 and extinction powder as the main functional filler. The experiment gets a good formula with suitable viscosity, low glossiness and good cooling effect, optimizes by orthogonal experiment. The experiment evaluates the indoor and outdoor cooling effect of heat-reflective coating, and analyses the road performance of the coating. The results shows that the better heat-reflective coating formula included 12% of titanium dioxide, 4% of silica and 4% of extinction powder. When the dosage of coating is 0.8kg/m2, the indoor specimen of heat-reflective coating decrease the temperature of 12 ˜ 14°C, and the specimen under solar radiation can reduce the temperature of 7 ˜ 9°C. The pavement of heat-reflective coating has good wear resistance, but the road slip resistance partly declines. Therefore, it needs to add the anti-sliding particles to meet the safe driving requirements.

  5. The evaluation of hydroxyapatite (HA) coated and uncoated porous tantalum for biomedical material applications

    International Nuclear Information System (INIS)

    Safuan, Nadia; Sukmana, Irza; Kadir, Mohammed Rafiq Abdul; Noviana, Deni

    2014-01-01

    Porous tantalum has been used as an orthopedic implant for bone defects as it has a good corrosion resistance and fatigue behaviour properties. However, there are some reports on the rejection of porous Ta after the implantation. Those clinical cases refer to the less bioactivity of metallic-based materials. This study aims to evaluate hydroxyapatite coated and uncoated porous Tantalum in order to improve the biocompatibility of porous tantalum implant and osseointegration. Porous tantalum was used as metallic-base substrate and hydroxyapatite coating has been done using plasma-spraying technique. Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM) techniques were utilizes to investigate the coating characteristics while Confocal Raman Microscopy to investigate the interface and image. The effect of coating to the corrosion behaviour was assessed by employing potentiodynamic polarization tests in simulated body fluid at 37±1 °C. Based on SEM and FESEM results, the morphologies as well the weight element consists in the uncoated and hydroxyapatite coated porous tantalum were revealed. The results indicated that the decrease in corrosion current density for HA coated porous Ta compared to the uncoated porous Ta. This study concluded that by coating porous tantalum with HA supports to decrease the corrosion rate of pure porous.

  6. The Evaluation of Hydroxyapatite (HA) Coated and Uncoated Porous Tantalum for Biomedical Material Applications

    Science.gov (United States)

    Safuan, Nadia; Sukmana, Irza; Kadir, Mohammed Rafiq Abdul; Noviana, Deni

    2014-04-01

    Porous tantalum has been used as an orthopedic implant for bone defects as it has a good corrosion resistance and fatigue behaviour properties. However, there are some reports on the rejection of porous Ta after the implantation. Those clinical cases refer to the less bioactivity of metallic-based materials. This study aims to evaluate hydroxyapatite coated and uncoated porous Tantalum in order to improve the biocompatibility of porous tantalum implant and osseointegration. Porous tantalum was used as metallic-base substrate and hydroxyapatite coating has been done using plasma-spraying technique. Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM) techniques were utilizes to investigate the coating characteristics while Confocal Raman Microscopy to investigate the interface and image. The effect of coating to the corrosion behaviour was assessed by employing potentiodynamic polarization tests in simulated body fluid at 37±1 °C. Based on SEM and FESEM results, the morphologies as well the weight element consists in the uncoated and hydroxyapatite coated porous tantalum were revealed. The results indicated that the decrease in corrosion current density for HA coated porous Ta compared to the uncoated porous Ta. This study concluded that by coating porous tantalum with HA supports to decrease the corrosion rate of pure porous.

  7. Aespoe Hard Rock Laboratory. Evaluation of scaling records for TASA access tunnel

    International Nuclear Information System (INIS)

    Ittner, Henrik

    2009-01-01

    This report presents the result of a project accomplished during the summer 2009. It introduces a method to estimate the magnitude, mass distribution and cause of scaled blocks by tunnel mapping and evaluation of scaling data records. These issues are important for understanding the impact of the excavation method on the surrounding rock mass during excavation of the planned underground repository for spent nuclear fuel. The project includes mapping of the 3120 m drill and blast excavated part of the TASA access tunnel in the Aespoe Hard Rock Laboratory (HRL). In addition it includes development of a method for evaluation of the collected material together with scaling data records from the Site Characterization Database (SICADA). An interview has also been held with Erik Gabrielsson, who has been in charge of tunnel maintenance at Aespoe for many years. The mapping focused on to identify size and cause of areas with significant overbreaks in the tunnel roof. By distributing documented scaled volume in a tunnel section on several mapped overbreak areas in the same section it is possible to reconstruct the size of scaled blocks. The observed overbreak areas have been categorized in five different area types, depending on the cause of scaling: two geologically induced, one blast induced, one induced from a combination of geology and blasting and one unable to place in any category. For the calculated mass distribution the number of observations is declining with increasing block mass. 11% of the total blocks exceeding 400 Kg and 75% of the scaled blocks weights under 200 Kg. Most of the blocks are however lighter with 34% weighting 50 Kg or less. There is a relation between the mapped area type and the size distribution among the mapped overbreak areas. For example the areas caused by the end of blasting rounds are more frequently appearing then the other types but most of them are small in relation to the others The impression achieved from the tunnel mapping is

  8. Aespoe Hard Rock Laboratory. Evaluation of scaling records for TASA access tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Ittner, Henrik (Chalmers Univ. of Technology, Goeteborg (Sweden))

    2009-07-01

    This report presents the result of a project accomplished during the summer 2009. It introduces a method to estimate the magnitude, mass distribution and cause of scaled blocks by tunnel mapping and evaluation of scaling data records. These issues are important for understanding the impact of the excavation method on the surrounding rock mass during excavation of the planned underground repository for spent nuclear fuel. The project includes mapping of the 3120 m drill and blast excavated part of the TASA access tunnel in the Aespoe Hard Rock Laboratory (HRL). In addition it includes development of a method for evaluation of the collected material together with scaling data records from the Site Characterization Database (SICADA). An interview has also been held with Erik Gabrielsson, who has been in charge of tunnel maintenance at Aespoe for many years. The mapping focused on to identify size and cause of areas with significant overbreaks in the tunnel roof. By distributing documented scaled volume in a tunnel section on several mapped overbreak areas in the same section it is possible to reconstruct the size of scaled blocks. The observed overbreak areas have been categorized in five different area types, depending on the cause of scaling: two geologically induced, one blast induced, one induced from a combination of geology and blasting and one unable to place in any category. For the calculated mass distribution the number of observations is declining with increasing block mass. 11% of the total blocks exceeding 400 Kg and 75% of the scaled blocks weights under 200 Kg. Most of the blocks are however lighter with 34% weighting 50 Kg or less. There is a relation between the mapped area type and the size distribution among the mapped overbreak areas. For example the areas caused by the end of blasting rounds are more frequently appearing then the other types but most of them are small in relation to the others The impression achieved from the tunnel mapping is

  9. Development and evaluation of suspension plasma sprayed yttria stabilized zirconia coatings as thermal barriers

    Science.gov (United States)

    van Every, Kent J.

    The insulating effects from thermal barrier coatings (TBCs) in gas turbine engines allow for increased operational efficiencies and longer service lifetimes. Consequently, improving TBCs can lead to enhanced gas turbine engine performance. This study was conducted to investigate if yttria-stabilized zirconia (YSZ) coatings, the standard industrial choice for TBCs, produced from nano-sized powder could provide better thermal insulation than current commericial YSZ coatings generated using micron-sized powders. The coatings for this research were made via the recently developed suspension plasma spraying (SPS) process. With SPS, powders are suspended in a solvent containing dispersing agents; the suspension is then injected directly into a plasma flow that evaporates the solvent and melts the powder while transporting it to the substrate. Although related to the industrial TBC production method of air plasma spraying (APS), SPS has two important differences---the ability to spray sub-micron diameter ceramic particles, and the ability to alloy the particles with chemicals dissolved in the solvent. These aspects of SPS were employed to generate a series of coatings from suspensions containing ˜100 nm diameter YSZ powder particles, some of which were alloyed with neodymium and ytterbium ions from the solvent. The SPS coatings contained columnar structures not observed in APS TBCs; thus, a theory was developed to explain the formation of these features. The thermal conductivity of the coatings was tested to evaluate the effects of these unique microstructures and the effects of the alloying process. The results for samples in the as-sprayed and heat-treated conditions were compared to conventional YSZ TBCs. This comparison showed that, relative to APS YSZ coatings, the unalloyed SPS samples typically exhibited higher as-sprayed and lower heat-treated thermal conductivities. All thermal conductivity values for the alloyed samples were lower than conventional YSZ TBCs

  10. Property Evaluation and Damage Evolution of Environmental Barrier Coatings and Environmental Barrier Coated SiC/SiC Ceramic Matrix Composite Sub-Elements

    Science.gov (United States)

    Zhu, Dongming; Halbig, Michael; Jaskowiak, Martha; Hurst, Janet; Bhatt, Ram; Fox, Dennis S.

    2014-01-01

    This paper describes recent development of environmental barrier coatings on SiC/SiC ceramic matrix composites. The creep and fatigue behavior at aggressive long-term high temperature conditions have been evaluated and highlighted. Thermal conductivity and high thermal gradient cyclic durability of environmental barrier coatings have been evaluated. The damage accumulation and complex stress-strain behavior environmental barrier coatings on SiCSiC ceramic matrix composite turbine airfoil subelements during the thermal cyclic and fatigue testing of have been also reported.

  11. Evaluation of the linearity of soft- to hard-tissue movement after orthognathic surgery

    NARCIS (Netherlands)

    Chew, Ming Tak; Sandham, John; Wong, Hwee Bee

    2008-01-01

    Introduction: Our aim in this study was to investigate whether a linear relationship exists between soft- to hard-tissue changes for both maxillary and mandibular landmarks over a wide range of skeletal changes. Methods: The sample consisted of 30 Chinese patients with Class III malocclusion treated

  12. Is Chronic Dialysis the Right Hard Renal End Point To Evaluate Renoprotective Drug Effects?

    NARCIS (Netherlands)

    Weldegiorgis, Misghina; de Zeeuw, Dick; Dwyer, Jamie P.; Mol, Peter; Heerspink, Hiddo J. L.

    2017-01-01

    Background and objectives: RRT and doubling of serum creatinine are considered the objective hard end points in nephrology intervention trials. Because both are assumed to reflect changes in the filtration capacity of the kidney, drug effects, if present, are attributed to kidney protection.

  13. Evaluation of the linearity of soft- to hard-tissue movement after orthognathic surgery

    NARCIS (Netherlands)

    Chew, Ming Tak; Sandham, John; Wong, Hwee Bee

    Introduction: Our aim in this study was to investigate whether a linear relationship exists between soft- to hard-tissue changes for both maxillary and mandibular landmarks over a wide range of skeletal changes. Methods: The sample consisted of 30 Chinese patients with Class III malocclusion treated

  14. A study to evaluate cephalometric hard tissue profile of Tamil population for orthognathic surgery.

    Science.gov (United States)

    Nachiappan, S; Tharanikumar, S; Chandran, Ajay; Anusudha, P; Nandini, G D; Balasubramaniam, Murali

    2015-08-01

    The primary aim of this study is to compare, the cephalometric hard tissue profile values and analysis between Tamil and Caucasian population. The study also aims to create a better understanding in the facial proportions of Tamil Nadu population and to have better diagnosis and treatment planning for orthognathic surgery for Tamil population in Tamil Nadu.

  15. Evaluation of mechanical properties of Aluminum-Copper cold sprayed and alloy 625 wire arc sprayed coatings

    Science.gov (United States)

    Bashirzadeh, Milad

    This study examines microstructural-based mechanical properties of Al-Cu composite deposited by cold spraying and wire arc sprayed nickel-based alloy 625 coating using numerical modeling and experimental techniques. The microhardness and elastic modulus of samples were determined using the Knoop hardness technique. Hardness in both transverse and longitudinal directions on the sample cross-sections has been measured. An image-based finite element simulation algorithm was employed to determine the mechanical properties through an inverse analysis. In addition mechanical tests including, tensile, bending, and nano-indentation tests were performed on alloy 625 wire arc sprayed samples. Overall, results from the experimental tests are in relatively good agreement for deposited Al-Cu composites and alloy 625 coating. However, results obtained from numerical simulation are significantly higher in value than experimentally obtained results. Examination and comparison of the results are strong indications of the influence of microstructure characteristics on the mechanical properties of thermally spray deposited coatings.

  16. Inorganic/organic hybrid nanocomposite coating applications: Formulation, characterization, and evaluation

    Science.gov (United States)

    Eyassu, Tsehaye

    Nanotechnology applications in coatings have shown significant growth in recent years. Systematic incorporation of nano-sized inorganic materials into polymer coating enhances optical, electrical, thermal and mechanical properties significantly. The present dissertation will focus on formulation, characterization and evaluation of inorganic/organic hybrid nanocomposite coatings for heat dissipation, corrosion inhibition and ultraviolet (UV) and near infrared (NIR) cut applications. In addition, the dissertation will cover synthesis, characterization and dispersion of functional inorganic fillers. In the first project, we investigated factors that can affect the "Molecular Fan" cooling performance and efficiency. The investigated factors and conditions include types of nanomaterials, size, loading amount, coating thickness, heat sink substrate, substrate surface modification, and power input. Using the optimal factors, MF coating was formulated and applied on commercial HDUs, and cooling efficiencies up to 22% and 23% were achieved using multi-walled carbon nanotube and graphene fillers. The result suggests that molecular fan action can reduce the size and mass of heat-sink module and thus offer a low cost of LED light unit. In the second project, we report the use of thin organic/inorganic hybrid coating as a protection for corrosion and as a thermal management to dissipate heat from galvanized steel. Here, we employed the in-situ phosphatization method for corrosion inhibition and "Molecular fan" technique to dissipate heat from galvanized steel panels and sheets. Salt fog tests reveal successful completion of 72 hours corrosion protection time frame for samples coated with as low as ~0.7microm thickness. Heat dissipation measurement shows 9% and 13% temperature cooling for GI and GL panels with the same coating thickness of ~0.7microm respectively. The effect of different factors, in-situ phosphatization reagent (ISPR), cross-linkers and nanomaterial on corrosion

  17. Evaluation of resistant starch, glycemic index and fortificants content of premix rice coated with various concentrations and types of edible coating materials

    Science.gov (United States)

    Yulianto, W. A.; Susiati, A. M.; Adhini, H. A. N.

    2018-01-01

    The incidence of diabetes in Indonesia has been increasing year by year. Diets with a low glycemic index and high resistant starch foods can assist diabetics in controlling their blood glucose levels. Diabetics are known to have micro-nutrient deficiencies of chromium, magnesium and vitamin D that can be overcome by consuming parboiled rice fortified by use of a coating method. The fortification of parboiled rice (premix rice) can be achieved by coating with HPMC (hydroxypropyl methyl cellulose), MC (methyl cellulose), CMC (carboxyl methyl cellulose), gum arabic and rice starch. This research aimed to evaluate the levels of resistant starch, glycemic index and fortificants of premix rice coated with different concentrations and types of edible coating materials. This research used completely randomized design, with treatments to the concentrations and the types of edible coating (HPMC, CMC, MC, gum arabic and rice starch). The concentrations of edible coating were 0.15%, 0.2% and 0.25% for cellulose derivative coatings; 25%, 30%, 35% for gum arabic and 2%, 3.5% and 5% for rice starch. This research shows that fortified premix rice coated with various concentrations and types of edible coating materials is high in resistant starch and has a low glycemic index. The coating treatment affects the levels of magnesium and vitamin D, but does not affect the levels of chromium in parboiled rice. The premix rice with a low glycemic index and high nutrient content (chromium, magnesium and vitamin D) was premix rice coated by CMC 0.25% and HPMC 0.25% with glycemic indeces of 39.34 and 38.50, respectively.

  18. The evaluation of integrity and elasticity of thermally sprayed ceramic coatings by ultrasonics

    Energy Technology Data Exchange (ETDEWEB)

    Kauppinen, P. [VTT Manufacturing Technology, Espoo (Finland). Materials and Structural Integrity

    1997-12-31

    Thermally sprayed ceramic coatings are widely used in industrial applications where the coated component is subject to, e.g. high thermal loads or mechanical wear. The mechanical properties of the coating are finally created in the coating process and the chemical composition of the powder used as raw material can only give some hints about the properties of the final coating. Several non-destructive testing techniques are available for the detection of defects in ceramic materials or for the evaluation of density and density variations. In addition to this, ultrasonic techniques can be used for quantitative evaluation of elastic properties of materials. This evaluation is based on the measurement of sound velocities of different wave modes in the material and is normally applied only to relatively simple-shaped specimens having parallel surfaces. Acoustic microscopy operating at very high (> 100 MHz) frequencies has been used to measure the sound velocities in homogeneous and thin coatings. With this type of equipment, reliable and accurate results have been achieved in laboratory measurements. A lot of development work has been carried out world-wide to develop the measurement techniques and acoustic lenses (transducers) used in acoustic microscopy. However, less attention has been paid on the development of techniques for industrial applications on-site. The present work was focused on the development of measurement techniques for industrial applications. A new type of large-aperture low-frequency transducer was designed and constructed for the measurement of sound velocities in thermally sprayed ceramic coatings. The major difference to the lenses used in acoustic microscopy is that in the new transducer no separate lens is needed for focusing the sound beam. The piezoelectric element in the new transducer is a plastic (PVDF)-film that can be shaped to create the required focus. The practical measurement of the sound velocity is based on a modification of the V

  19. SiO2@TiO2 Coating: Synthesis, Physical Characterization and Photocatalytic Evaluation

    Directory of Open Access Journals (Sweden)

    A. Rosales

    2018-03-01

    Full Text Available Use of silicon dioxide (SiO2 and titanium dioxide (TiO2 have been widely investigated individually in coatings technology, but their combined properties promote compatibility for different innovative applications. For example, the photocatalytic properties of TiO2 coatings, when exposed to UV light, have interesting environmental applications, such as air purification, self-cleaning and antibacterial properties. However, as reported in different pilot projects, serious durability problems, associated with the adhesion between the substrate and TiO2, have been evidenced. Thus, the aim of this work is to synthesize SiO2 together with TiO2 to increase the durability of the photocatalytic coating without affecting its photocatalytic potential. Therefore, synthesis using sonochemistry, synthesis without sonochemistry, physical characterization, photocatalytic evaluation, and durability of the SiO2, SiO2@TiO2 and TiO2 coatings are presented. Results indicate that using SiO2 improved the durability of the TiO2 coating without affecting its photocatalytic properties. Thus, this novel SiO2@TiO2 coating shows potential for developing long-lasting, self-cleaning and air-purifying construction materials.

  20. Development of combinatorial chemistry methods for coatings: high-throughput adhesion evaluation and scale-up of combinatorial leads.

    Science.gov (United States)

    Potyrailo, Radislav A; Chisholm, Bret J; Morris, William G; Cawse, James N; Flanagan, William P; Hassib, Lamyaa; Molaison, Chris A; Ezbiansky, Karin; Medford, George; Reitz, Hariklia

    2003-01-01

    Coupling of combinatorial chemistry methods with high-throughput (HT) performance testing and measurements of resulting properties has provided a powerful set of tools for the 10-fold accelerated discovery of new high-performance coating materials for automotive applications. Our approach replaces labor-intensive steps with automated systems for evaluation of adhesion of 8 x 6 arrays of coating elements that are discretely deposited on a single 9 x 12 cm plastic substrate. Performance of coatings is evaluated with respect to their resistance to adhesion loss, because this parameter is one of the primary considerations in end-use automotive applications. Our HT adhesion evaluation provides previously unavailable capabilities of high speed and reproducibility of testing by using a robotic automation, an expanded range of types of tested coatings by using the coating tagging strategy, and an improved quantitation by using high signal-to-noise automatic imaging. Upon testing, the coatings undergo changes that are impossible to quantitatively predict using existing knowledge. Using our HT methodology, we have developed several coatings leads. These HT screening results for the best coating compositions have been validated on the traditional scales of coating formulation and adhesion loss testing. These validation results have confirmed the superb performance of combinatorially developed coatings over conventional coatings on the traditional scale.

  1. Evaluation of stiffness feedback for hard nodule identification on a phantom silicone model

    OpenAIRE

    Li, M.; Konstantinova, J.; Xu, G.; He, B.; Aminzadeh, V.; Xie, J.; Wurdemann, H.; Althoefer, K.

    2017-01-01

    Haptic information in robotic surgery can significantly improve clinical outcomes and help detect hard soft-tissue inclusions that indicate potential abnormalities. Visual representation of tissue stiffness information is a cost-effective technique. Meanwhile, direct force feedback, although considerably more expensive than visual representation, is an intuitive method of conveying information regarding tissue stiffness to surgeons. In this study, real-time visual stiffness feedback by slidin...

  2. Non destructive evaluation of residual stresses in welding and hard-surfacing processes

    International Nuclear Information System (INIS)

    Suarez, J.C.; Fernandez, L.M.; Cruz, C.; Aragon, B.; Merino, F.

    1995-01-01

    In this paper transversal and longitudinal stress profiles in welding and hard-surfacing by welding processes are presented. The stresses were measured by RMS of Barkhausen signal. In this work it is shown that in each case the level of stresses is strongly dependent on the number of weld beads of surfacing layers deposited. The subsequent deposition of new weld beads or surfacing layers produces a stress-relieving effect

  3. Evaluation of erbium:YAG and holmium:YAG laser radiation and dental hard tissue

    Science.gov (United States)

    Attrill, David Cameron

    Lasers have become increasingly established in medicine as effective alternatives or adjuncts to conventional techniques. In dentistry, several clinical laser systems have been developed and marketed, but their applications have been limited to soft tissue surgery. To date, no laser has been capable of effectively cutting or modifying the highly mineralised dental tissues of enamel and dentine. The aim of this study was to evaluate two new laser systems for use in dentistry through a series of in vitro experiments. Both generic erbium and holmium lasers have theoretically superior operating characteristics over currently established lasers for applications with dental hard tissues. The two lasers investigated in this study were pulsed Er:YAG (lambda=2.94) a.m. and Cr-Tm-Ho:YAG (lambda=2.1mu.m). Both operated with a macropulse duration of approximately 200lambdas, at pulse repetition rates of 2-8Hz and mean pulse energies up to 230mJ. Radiation was focused using CaF[2] lenses (f=50-120mm). The lasers could be operated with or without the addition of a surface water film at the interaction site. Tissue removal efficiency was expressed as a latent heat of ablation (LHA, kJ/cm[3]) using a modification of the technique described by Charlton et al. (1990). The mean LHA's for the Er:YAG laser were 6.24kJ/cm[3] and 22.99kJ/cm[3] with dentine and enamel respectively without water, and 10.07kJ/cm[3] and 18.73kJ/cm[3] for dentine and enamel with water. The Cr-Tm-Ho:YAG laser was unable to effectively remove enamel at the fluences and pulse energies available; the mean LHA's for the Cr-Tm- Ho:YAG laser with dentine were 82.79kJ/cm3 and 57.57kJ/cm3 with and without water respectively. The Cr-Tm-Ho;YAG was approximately 8-9 times less efficient for tissue removal than the Er:YAG system. Er:YAG tissue removal with water was characterised by clean "surgical" cuts, comparable in histological appearance to those obtained using conventional instrumentation. Some thermal disruption

  4. Evaluation of the coat quality of sustained release pellets by individual pellet dissolution methodology.

    Science.gov (United States)

    Xu, Min; Liew, Celine Valeria; Heng, Paul Wan Sia

    2015-01-15

    This study explored the application of 400-DS dissolution apparatus 7 for individual pellet dissolution methodology by a design of experiment approach and compared its capability with that of the USP dissolution apparatus 1 and 2 for differentiating the coat quality of sustained release pellets. Drug loaded pellets were prepared by extrusion-spheronization from powder blends comprising 50%, w/w metformin, 25%, w/w microcrystalline cellulose and 25%, w/w lactose, and then coated with ethyl cellulose to produce sustained release pellets with 8% and 10%, w/w coat weight gains. Various pellet properties were investigated, including cumulative drug release behaviours of ensemble and individual pellets. When USP dissolution apparatus 1 and 2 were used for drug release study of the sustained release pellets prepared, floating and clumping of pellets were observed and confounded the release profiles of the ensemble pellets. Hence, the release profiles obtained did not characterize the actual drug release from individual pellet and the applicability of USP dissolution apparatus 1 and 2 to evaluate the coat quality of sustained release pellets was limited. The cumulative release profile of individual pellet using the 400-DS dissolution apparatus 7 was found to be more precise at distinguishing differences in the applied coat quality. The dip speed and dip interval of the reciprocating holder were critical operational parameters of 400-DS dissolution apparatus 7 that affected the drug release rate of a sustained release pellet during the individual dissolution study. The individual dissolution methodology using the 400-DS dissolution apparatus 7 is a promising technique to evaluate the individual pellet coat quality without the influence of confounding factors such as pellet floating and clumping observed during drug release test with dissolution apparatus 1 and 2, as well as to facilitate the elucidation of the actual drug release mechanism conferred by the applied sustained

  5. Microstructure Characterization and Hardness Evaluation of Alloy 52 Welded Stainless Steel 316 Subjected to Ultrasonic Nanocyrtal Surface Modification Technique

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H. D.; Amanov, A.; Pyun, Y. S. [Sun Moon Univ., Asan (Korea, Republic of); Kim, Y. S.; Choi, Y. S. [Andong National Univ., Andong (Korea, Republic of)

    2015-10-15

    In this study, an ultrasonic nanocrystal surface modification (UNSM) technique was applied to dissimilar weld point between STS316L and Alloy 52. This UNSM technique is a patented technology, which can be described as a type of ultrasonic cold-forging technology. It has been demonstrated that the UNSM technique is a simple method to produce a nanocrystalline surface layer at the top surface of metallic materials. Microstructure and hardness of STS316L and Alloy 52 are investigated before and after UNSM treatment. It is expected according to the previous study that the UNSM technique is able to release the residual stress which delays PWSCC. In this study, microstructural characterization and hardness evaluation of STS316L and welded Alloy 52 subjected to UNSM technique were investigated.

  6. Effects of Different Levels of Boron on Microstructure and Hardness of CoCrFeNiAlxCu0.7Si0.1By High-Entropy Alloy Coatings by Laser Cladding

    Directory of Open Access Journals (Sweden)

    Yizhu He

    2017-01-01

    Full Text Available High-entropy alloys (HEAs are novel solid solution strengthening metallic materials, some of which show attractive mechanical properties. This paper aims to reveal the effect of adding small atomic boron on the interstitial solid solution strengthening ability in the laser cladded CoCrFeNiAlxCu0.7Si0.1By (x = 0.3, x = 2.3, and 0.3 ≤ y ≤ 0.6 HEA coatings. The results show that laser rapid solidification effectively prevents brittle boride precipitation in the designed coatings. The main phase is a simple face-centered cubic (FCC matrix when the Al content is equal to 0.3. On the other hand, the matrix transforms to single bcc solid solution when x increases to 2.3. Increasing boron content improves the microhardness of the coatings, but leads to a high degree of segregation of Cr and Fe in the interdendritic microstructure. Furthermore, it is worth noting that CoCrFeNiAl0.3Cu0.7Si0.1B0.6 coatings with an FCC matrix and a modulated structure on the nanometer scale exhibit an ultrahigh hardness of 502 HV0.5.

  7. Investigation of metallurgical coatings for automotive applications

    Science.gov (United States)

    Su, Jun Feng

    Metallurgical coatings have been widely used in the automotive industry from component machining, engine daily running to body decoration due to their high hardness, wear resistance, corrosion resistance and low friction coefficient. With high demands in energy saving, weight reduction and limiting environmental impact, the use of new materials such as light Aluminum/magnesium alloys with high strength-weight ratio for engine block and advanced high-strength steel (AHSS) with better performance in crash energy management for die stamping, are increasing. However, challenges are emerging when these new materials are applied such as the wear of the relative soft light alloys and machining tools for hard AHSS. The protective metallurgical coatings are the best option to profit from these new materials' advantages without altering largely in mass production equipments, machinery, tools and human labor. In this dissertation, a plasma electrolytic oxidation (PEO) coating processing on aluminum alloys was introduced in engine cylinder bores to resist wear and corrosion. The tribological behavior of the PEO coatings under boundary and starve lubrication conditions was studied experimentally and numerically for the first time. Experimental results of the PEO coating demonstrated prominent wear resistance and low friction, taking into account the extreme working conditions. The numerical elastohydrodynamic lubrication (EHL) and asperity contact based tribological study also showed a promising approach on designing low friction and high wear resistant PEO coatings. Other than the fabrication of the new coatings, a novel coating evaluation methodology, namely, inclined impact sliding tester was presented in the second part of this dissertation. This methodology has been developed and applied in testing and analyzing physical vapor deposition (PVD)/ chemical vapor deposition (CVD)/PEO coatings. Failure mechanisms of these common metallurgical hard coatings were systematically

  8. Evaluation of self-healing ability of Ce–V conversion coating on AZ31 magnesium alloy

    Directory of Open Access Journals (Sweden)

    Xiao Jiang

    2016-09-01

    Full Text Available This study investigated the influence of cerium nitrate in vanadate solutions on the properties of Ce–V conversion coatings on AZ31 magnesium alloys, and evaluated the self-healing behavior of the Ce–V conversion coating for AZ31 magnesium alloy. The results showed that the additions of cerium nitrate prevented pentavalent vanadium from reducing to tetravalent vanadium in the coatings during conversion reaction process. Adding appropriate cerium nitrate to vanadate solution led to a thicker coating with a more compact CeVO4 layer. The corrosion behavior of the Ce–V conversion coating was investigated by the electrochemical tests and the scratch immersion test in 3.5 wt.% NaCl solution. The self-healing ability of the coating was confirmed from all tests. The surface analysis revealed that the self-healing effect of the Ce–V conversion coating was only provided by the release and migration of vanadium compounds.

  9. Thermal Conductivity of EB-PVD Thermal Barrier Coatings Evaluated by a Steady-State Laser Heat Flux Technique

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.; Nagaraj, Ben A.; Bruce, Robert W.

    2000-01-01

    The thermal conductivity of electron beam-physical vapor deposited (EB-PVD) Zr02-8wt%Y2O3 thermal barrier coatings was determined by a steady-state heat flux laser technique. Thermal conductivity change kinetics of the EB-PVD ceramic coatings were also obtained in real time, at high temperatures, under the laser high heat flux, long term test conditions. The thermal conductivity increase due to micro-pore sintering and the decrease due to coating micro-delaminations in the EB-PVD coatings were evaluated for grooved and non-grooved EB-PVD coating systems under isothermal and thermal cycling conditions. The coating failure modes under the high heat flux test conditions were also investigated. The test technique provides a viable means for obtaining coating thermal conductivity data for use in design, development, and life prediction for engine applications.

  10. Sputtered titanium oxynitride coatings for endosseous applications: Physical and chemical evaluation and first bioactivity assays

    Energy Technology Data Exchange (ETDEWEB)

    Banakh, Oksana, E-mail: oksana.banakh@he-arc.ch [Institute of Applied Microtechnologies, Haute Ecole Arc Ingénierie (HES-SO), Eplatures-Grise 17, CH-2300 La Chaux-de-Fonds (Switzerland); Moussa, Mira, E-mail: mira.moussa@unige.ch [Laboratory of Biomaterials, University of Geneva, 19, rue Barthelemy Menn, CH-1205 Geneva (Switzerland); Matthey, Joel, E-mail: joel.matthey@he-arc.ch [Institute of Applied Microtechnologies, Haute Ecole Arc Ingénierie (HES-SO), Eplatures-Grise 17, CH-2300 La Chaux-de-Fonds (Switzerland); Pontearso, Alessandro, E-mail: alessandro.pontearso@he-arc.ch [Institute of Applied Microtechnologies, Haute Ecole Arc Ingénierie (HES-SO), Eplatures-Grise 17, CH-2300 La Chaux-de-Fonds (Switzerland); Cattani-Lorente, Maria, E-mail: maria.cattani-lorente@unige.ch [Laboratory of Biomaterials, University of Geneva, 19, rue Barthelemy Menn, CH-1205 Geneva (Switzerland); Sanjines, Rosendo, E-mail: rosendo.sanjines@epfl.ch [Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Condensed Matter Physics, Station 3, CH-1015 Lausanne (Switzerland); Fontana, Pierre, E-mail: Pierre.Fontana@hcuge.ch [Haemostasis laboratory, Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4, CH-1205 Geneva (Switzerland); Wiskott, Anselm, E-mail: anselm.wiskott@unige.ch [Laboratory of Biomaterials, University of Geneva, 19, rue Barthelemy Menn, CH-1205 Geneva (Switzerland); Durual, Stephane, E-mail: stephane.durual@unige.ch [Laboratory of Biomaterials, University of Geneva, 19, rue Barthelemy Menn, CH-1205 Geneva (Switzerland)

    2014-10-30

    Highlights: • Titanium oxynitride coatings (TiN{sub x}O{sub y}) with chemical composition ranging from TiN to TiO{sub 2} were deposited by magnetron sputtering from a metallic Ti target using a mixture of O{sub 2} + N{sub 2}. • The coatings structure as well as physical, chemical and mechanical properties progressively changes as a function of oxygen content in the TiN{sub x}O{sub y.} • All TiN{sub x}O{sub y} coatings show a significantly higher level of bioactivity as compared to bare Ti substrates (1.2 to 1.4 fold increase in cell proliferation). Despite variations in surface chemistry, topography and surface tension observed on films as a function of chemical composition, no significant differences in the films’ biological activity were observed after 3 days of testing. - Abstract: Titanium oxynitride coatings (TiN{sub x}O{sub y}) are considered a promising material for applications in dental implantology due to their high corrosion resistance, their biocompatibility and their superior hardness. Using the sputtering technique, TiN{sub x}O{sub y} films with variable chemical compositions can be deposited. These films may then be set to a desired value by varying the process parameters, that is, the oxygen and nitrogen gas flows. To improve the control of the sputtering process with two reactive gases and to achieve a variable and controllable coating composition, the plasma characteristics were monitored in-situ by optical emission spectroscopy. TiN{sub x}O{sub y} films were deposited onto commercially pure (ASTM 67) microroughened titanium plates by reactive magnetron sputtering. The nitrogen gas flow was kept constant while the oxygen gas flow was adjusted for each deposition run to obtain films with different oxygen and nitrogen contents. The physical and chemical properties of the deposited films were analyzed as a function of oxygen content in the titanium oxynitride. The potential application of the coatings in dental implantology was assessed by

  11. A microbiological evaluation of SiO2-coated textiles in hospital interiors

    DEFF Research Database (Denmark)

    Mogensen, Jeppe; Jørgensen, Poul-Erik; Thomsen, Trine Rolighed

    2016-01-01

    . From this perspective, the purpose of this paper is therefore to address focus on alternative passive coatings that without actively killing the bacteria provide a hydrophobic and easy-to-clean textile surface. The paper relates to an in-situ study evaluating the effect and cleaning potential of SiO2...... contact plates through a three-week period. By determining the level of contamination on these surfaces, the study illustrates that the SiO2-coated textile is possible to clean to an acceptable level below the critical limit value of 2,5 Colony Forming Units (CFU) per cm2. In comparison, the traditional...

  12. Evaluation of Metal Ion Concentration in Hard Tissues of Teeth in Residents of Central Poland

    Directory of Open Access Journals (Sweden)

    Piotr Wychowanski

    2017-01-01

    Full Text Available Objectives. The aim of the study was an assessment of the content of trace elements in enamel and dentin of teeth extracted in patients residing in urban and agricultural areas of Poland. Methods. The study included 30 generally healthy patients with retained third molars. 65 samples of enamel and dentin from individuals living in urban areas and 85 samples of enamel and dentin from individuals living in agricultural areas were prepared. The content of manganese, lead, cadmium, and chromium in the studied enamel and dentin samples from retained teeth was determined by Graphite Furnace Atomic Absorption Spectrometry. In the process of statistical hypothesis testing, the level of significance was assumed at α=0.05. Results. A comparative analysis of the data showed that enamel and dentin of inhabitants of industrialized areas contain significantly higher amounts of lead and cadmium than hard tissues of teeth in residents of agricultural areas and comparable amounts of manganese and chromium. Significance. It appears that hard tissues of retained teeth may constitute valuable material for assessment of long-term environmental exposure to metal ions. The study confirms that the risk of exposure to heavy metals depends on the place of residence and environmental pollution.

  13. Application of pulsed laser for evaluation and optimization of SEU-Hard Designs

    International Nuclear Information System (INIS)

    McMorrow, D.; Melinger, J.S.; Buchner, St.; Scott, T.; Brown, R.D.

    1999-01-01

    Pulsed laser SEU tests are used to pinpoint and characterize sensitive nodes of CMOS circuits and to provide feedback relevant to the development and optimization of radiation-hard designs. The present study reveals several examples of the quantitative utility of the laser system. The most direct approach to obtaining quantitative thresholds from laser SEU tests involved a calibration of the measured laser upset thresholds against heavy ion results. This procedure requires only a correlation between the laser and heavy ion measurements. This study shows that this correlation exists and is particularly strong and that the calibration factor is identical to that determined in previous studies. The laser SEU threshold energy corresponds to the most sensitive node located with the laser probe. The ion-equivalent laser LET is calculated using the calibration factor noted above. The measured heavy ion threshold is given as a range since heavy-ion upset measurements are discrete: the upper value gives the lowest LET ion to induce an upset; the lower value gives the next lower LET investigated. Laser SEU measurements often can be used directly for hardness assurance or diagnosis studies. (A.C.)

  14. Steam oxidation and the evaluation of coatings and material performance through collaborative research

    Energy Technology Data Exchange (ETDEWEB)

    Fry, A.T. [National Physical Lab., Teddington (United Kingdom); Aguero, A. [INTA, Madrid (Spain)

    2010-07-01

    Over the last five years through the COST 536 Programme researchers across Europe have been collaborating to better understand the phenomena of steam oxidation and to characterise coated and uncoated materials for use in power plants. During this period fundamental study of the oxidation mechanisms and changes in the oxidation kinetics caused by the presence of steam have been undertaken. Materials covering a range of high temperature plant applications have been studied, from low alloy martensitic alloys through to Ni-based superalloy materials, with investigations into the effect of increasing temperatures and pressures on the oxidation kinetics, oxide morphology and spallation characteristics. In addition conventional and novel coatings have been evaluated to assess their potential use in new USC plant. This paper will present an overview of these activities demonstrating the effect that steam has on the oxidation of alloys and coatings. (orig.)

  15. Synthesis and Performance Evaluation of Pulse Electrodeposited Ni-AlN Nanocomposite Coatings

    Directory of Open Access Journals (Sweden)

    Kamran Ali

    2018-01-01

    Full Text Available This research work presents the microscopic analysis of pulse electrodeposited Ni-AlN nanocomposite coatings using SEM and AFM techniques and their performance evaluation (mechanical and electrochemical by employing nanoindentation and electrochemical methods. The Ni-AlN nanocomposite coatings were developed by pulse electrodeposition. The nickel matrix was reinforced with various amounts of AlN nanoparticles (3, 6, and 9 g/L to develop Ni-AlN nanocomposite coatings. The effect of reinforcement concentration on structure, surface morphology, and mechanical and anticorrosion properties was studied. SEM and AFM analyses indicate that Ni-AlN nanocomposite coatings have dense, homogenous, and well-defined pyramid structure containing uniformly distributed AlN particles. A decent improvement in the corrosion protection performance is also observed by the addition of AlN particles to the nickel matrix. Corrosion current was reduced from 2.15 to 1.29 μA cm−2 by increasing the AlN particles concentration from 3 to 9 g/L. It has been observed that the properties of Ni-AlN nanocomposite coating are sensitive to the concentration of AlN nanoparticles used as reinforcement.

  16. Evaluation of the corrosion resistance of Ni-Co-B coatings in simulated PEMFC environment

    Energy Technology Data Exchange (ETDEWEB)

    Gamboa, S.A.; Valenzuela, E.; Sebastian, P.J. [CIE-UNAM, 62580 Temixco, Morelos (Mexico); Gonzalez-Rodriguez, J.G. [UAEM-CIICAp, Av. Universidad 1001, Col. Chamilpa, 62210 Cuernavaca, Mor. (Mexico); Campillo, B. [Facultad de Quimica-UNAM, Cd. Universitaria, DF, CP 04510 (Mexico); Reyes-Rojas, A. [CIMAV, Miguel de Cervantes 120, Complejo Ind. Chihuahua, 31109 Chihuahua, Chih. (Mexico)

    2006-05-20

    The corrosion resistance behavior of Ni-Co-B coated carbon steel, Al 6061 alloy and 304 stainless steel was evaluated in simulated proton exchange membrane fuel cell (PEMFC) environment. The phase structure of the NiCoB based alloy was determined by Rietveld analysis. The PEMFC environment was constituted of 0.5M H{sub 2}SO{sub 4} at 60{sup o}C and the evaluation techniques employed included potentiodynamic polarization, linear polarization resistance, open circuit potential measurements and electrochemical impedance spectroscopy. The results showed that in all cases the corrosion resistance of the Ni-Co-B coating was higher than that of the uncoated alloys; about two orders of magnitude with respect to carbon steel and an order of magnitude compared to 304 stainless steel. Except for the uncoated 304 type stainless steel, the polarization curves for the coated specimens did not exhibit a passive region but only anodic dissolution. The corrosion potential value, E{sub corr}, was always nobler for the coated samples than for the uncoated specimens. This was true for the stainless steel in the passive region, but in the active state for the carbon steel and Al 6061 alloy. The corrosion of the underlying alloy occurred due to filtering of the solution through coating defects like microcracks, pinholes, etc. During the filtering process the E{sub corr} value of the coating decreased slowly until it reached a steady state value, close to the E{sub corr} value of the underlying alloy. (author)

  17. Silver-doped nanocomposite carbon coatings (Ag-DLC) for biomedical applications - Physiochemical and biological evaluation

    Science.gov (United States)

    Bociaga, Dorota; Komorowski, Piotr; Batory, Damian; Szymanski, Witold; Olejnik, Anna; Jastrzebski, Krzysztof; Jakubowski, Witold

    2015-11-01

    The formation of bacteria biofilm on the surface of medical products is a major clinical issue nowadays. Highly adaptive ability of bacteria to colonize the surface of biomaterials causes a lot of infections. This study evaluates samples of the AISI 316 LVM with special nanocomposite silver-doped (by means of ion implantation) diamond-like carbon (DLC) coating prepared by hybrid RF/MS PACVD (radio frequency/magnetron sputtering plasma assisted chemical vapour deposition) deposition technique in order to improve the physicochemical and biological properties of biomaterials and add new features such as antibacterial properties. The aim of the following work was to evaluate antimicrobial efficacy and biocompatibility of gradient a-C:H/Ti + Ag coatings in relation to the physiochemical properties of the surface and chemical composition of coating. For this purpose, samples were tested in live/dead test using two cell strains: human endothelial cells (Ea.hy926) and osteoblasts-like cells (Saos-2). For testing bactericidal activity of the coatings, an exponential growth phase of Escherichia coli strain DH5α was used as a model microorganism. Surface condition and its physicochemical properties were investigated using SEM, AFM and XPS. Examined coatings showed a uniformity of silver ions distribution in the amorphous DLC matrix, good biocompatibility in contact with mammalian cells and an increased level of bactericidal properties. What is more, considering very good mechanical parameters of these Ag including gradient a-C:H/Ti coatings, they constitute an excellent material for biomedical application in e.g. orthopedics or dentistry.

  18. Evaluation of thermal sprayed metallic coatings for use on the structures at Launch Complex 39

    Science.gov (United States)

    Welch, Peter J.

    1990-01-01

    The current status of the evaluation program is presented. The objective was to evaluate the applicability of Thermal Sprayed Coatings (TSC) to protect the structures in the high temperature acid environment produced by exhaust of the Solid Rocket Boosters during the launches of the Shuttle Transportation System. Only the relatively low cost aluminum TSC which provides some cathodic protection for steel appears to be a practical candidate for further investigation.

  19. Clinical evaluation on the coaxial microincision cataract surgery in hard nuclear cataracts

    Directory of Open Access Journals (Sweden)

    Qing-Cheng Shi

    2013-05-01

    Full Text Available AIM: To assess and compare the results of 2.2mm microincision coaxial cataract surgery(MCCSphacoemulsification with the conventional 3.0mm MCCS in hard nuclear cataracts. METHODS: Totally 132 eyes with hard cataract(Ⅳ level and abovewere randomized to two groups: 2.2mm MCCS(group 1:60 eyesand 3.0mm MCCS(group 2:72 eyes. All patients underwent standard phacoemulsification and intraocular lens implantation surgery by one experienced surgeon. The average ultrasound power(AVEwas recorded during the operation. The incidences of capsule rupture and postoperative corneal edema were compared.Visual acuity, surgically induced astigmatism(SIAand the descent rate of endothelial cell density were compared at intervals of 1 day, 1 month and 3 months after surgery. Statistic analysis was taken by Student's t test and Chi square test. RESULTS: There was no significant difference on the incidences of capsule rupture, postoperative corneal edema and AVE(P> 0.05between the two groups(3.3%, 10.0%, 65.09±20.15and(4.2%, 11.1%, 69.13±15.44. One day after the surgery, the 2.2mm MCCS group showed better uncorrected visual acuity as compared to the 3.0mm MCCS group(P < 0.05. There were no significant differences on best-corrected visual acuity on 1 month and 3 months after the surgery. There was no significant difference on the descent rate of endothelial cell density(16.54%±10.20%, 17.69%±10.65%3 months after the surgery. One day, 1 month and 3 months after the surgery, SIA was 0.77±0.31,0.66±0.29, 0.52±0.25D in the 2.2mm MCCS group, and 1.41±0.73,0.98±0.61D,0.82±0.35D in the 3.0mm MCCS group, respectively. The differences were statistically significant. CONCLUSION: The operative safety of the 2.2mm MCCS group were the same as 3.0mm MCCS group with the hard nuclear cataracts. The 2.2mm MCCS phacoemulsification could significantly reduce SIA and get better earlier visual rehabilitation.

  20. Evaluation of seed priming and coating on emergence, yield and ...

    African Journals Online (AJOL)

    Bread wheat production is constrained by climate change impacts and diseases in Amhara region. Pre-farming seed treatments are practiced worldwide to avert their effects on wheat. A field experiment was conducted at Adet and Finoteselam research stations in 2014 main cropping season to evaluate the effects of seed ...

  1. Additive manufacturing of Ti-Si-N ceramic coatings on titanium

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanning; Sahasrabudhe, Himanshu; Bandyopadhyay, Amit, E-mail: amitband@wsu.edu

    2015-08-15

    Highlights: • 3D Printing or additive manufacturing of hard Ti-Si-N based ceramics coating on Ti metal substrate. • Understanding of phase transformation as a function of compositional variation. • Evaluation of influence of processing parameters and composition on wear resistance. - Abstract: In this study, Laser Engineered Net Shaping (LENS{sup TM}) was employed towards Additive Manufacturing/3D Printing of Ti-Si-N coatings with three different Ti-Si ratios on commercially pure titanium (cp-Ti) substrate. Microstructural analysis, phase analysis using X-ray diffraction, wear resistance and hardness measurements were done on LENS™ processed 3D printed coatings. Coatings showed graded microstructures and in situ formed phases. Results showed that microstructural variations and phase changes influence coating's hardness and wear resistance directly. High hardness values were obtained from all samples’ top surface where the hardness of coatings can be ranked as 90% Ti-10% Si-N coating (2093.67 ± 144 HV{sub 0.2}) > 100% Ti-N coating (1846 ± 68.5 HV{sub 0.2}) > 75% Ti-25% Si-N coating (1375.3 ± 61.4 HV{sub 0.2}). However, wear resistance was more dependent on inherent Si content, and samples with higher Si content showed better wear resistance.

  2. Additive manufacturing of Ti-Si-N ceramic coatings on titanium

    International Nuclear Information System (INIS)

    Zhang, Yanning; Sahasrabudhe, Himanshu; Bandyopadhyay, Amit

    2015-01-01

    Highlights: • 3D Printing or additive manufacturing of hard Ti-Si-N based ceramics coating on Ti metal substrate. • Understanding of phase transformation as a function of compositional variation. • Evaluation of influence of processing parameters and composition on wear resistance. - Abstract: In this study, Laser Engineered Net Shaping (LENS TM ) was employed towards Additive Manufacturing/3D Printing of Ti-Si-N coatings with three different Ti-Si ratios on commercially pure titanium (cp-Ti) substrate. Microstructural analysis, phase analysis using X-ray diffraction, wear resistance and hardness measurements were done on LENS™ processed 3D printed coatings. Coatings showed graded microstructures and in situ formed phases. Results showed that microstructural variations and phase changes influence coating's hardness and wear resistance directly. High hardness values were obtained from all samples’ top surface where the hardness of coatings can be ranked as 90% Ti-10% Si-N coating (2093.67 ± 144 HV 0.2 ) > 100% Ti-N coating (1846 ± 68.5 HV 0.2 ) > 75% Ti-25% Si-N coating (1375.3 ± 61.4 HV 0.2 ). However, wear resistance was more dependent on inherent Si content, and samples with higher Si content showed better wear resistance

  3. Evaluation of radiation effects on dental enamel hardness and dental restorative materials

    International Nuclear Information System (INIS)

    Adachi, Lena Katekawa; Saiki, Mitiko; Campos, Tomie Nakakuki

    2000-01-01

    This research presents the results of the microhardness of human dental enamel and of the following dental restorative materials: three dental porcelains - Ceramco II, Finesse and Noritake, and two resin restorative materials - Artglass and Targis, for materials submitted to different times of irradiation at the IEA-R1m nuclear reactor under a thermal neutron flux of 10 12 n cm -2 .s -1 . The results obtained indicated that there is a decrease of the surface microhardness when the enamel is irradiated for 1 h and when dental materials are irradiated for 3 h. However, enamels irradiated for 30 min. did not show significant change of their surface hardness. Therefore, the selection of irradiation time is an important factor to be considered when irradiated teeth or dental materials are used in the investigations of their properties. (author)

  4. Reliability evaluation of hard disk drive failures based on counting processes

    International Nuclear Information System (INIS)

    Ye, Zhi-Sheng; Xie, Min; Tang, Loon-Ching

    2013-01-01

    Reliability assessment for hard disk drives (HDDs) is important yet difficult for manufacturers. Motivated by the fact that the particle accumulation in the HDDs, which accounts for most HDD catastrophic failures, is contributed from the internal and external sources, a counting process with two arrival sources is proposed to model the particle cumulative process in HDDs. This model successfully explains the collapse of traditional ALT approaches for accelerated life test data. Parameter estimation and hypothesis tests for the model are developed and illustrated with real data from a HDD test. A simulation study is conducted to examine the accuracy of large sample normal approximations that are used to test existence of the internal and external sources.

  5. General evaluation of hard dental tissue and risk factors of dental caries in young people

    Directory of Open Access Journals (Sweden)

    Антоніна Михайлівна Політун

    2016-04-01

    Full Text Available The prognostication of caries in youth is important for determination and prescription of individual prophylactic arrangements and its further influence on mineralization of the hard dental tissues.Aim of the work: the study of the prevalence and intensity of caries among the young people and determination of possible connection with the risk factor of caries development for further choice of the reasonable prophylactic arrangement.Materials and methods of research: epidemiological, clinical, statistic ones.Results of research: The article describes results of the comprehensive dental examination of 135 persons18-25 years old. There was determined the high prevalence of caries (96,3±0,74 % with considerable intensity (8,87±0,39. The main etiological factors among youth are: poor nutrition with prevalence of carbohydrate (74,81±0,56 %, lack of oral hygiene (59,27±0,73 %, quantitative and qualitative composition of oral fluid, presence of somatic diseases (40±0,30 %, bad habits (31,85±0,24 %, neglect of the sport (48,88±0,36 %, chronic emotional stress (38,51±0,29 %, due to the increased workload and related stress factors.Conclusions: the high prevalence (96,3±0,74 % and intensity of carious process (8,87±0,39 is caused by the unsatisfactory state of oral cavity, (1,91±0,06, under the influence of general factors (somatic diseases, stress, poor nutrition the reactivity of protective mechanisms is lowered and the risk of dental morbidity of youth increases. So, it proves the necessity of elaboration and introduction of the active arrangements of primary prophylaxis directed on the raise of caries resistance of the hard dental tissues in young people

  6. Nanomechanical properties of hafnium nitride coating

    International Nuclear Information System (INIS)

    Chen Yao; Laha, Tapas; Balani, Kantesh; Agarwal, Arvind

    2008-01-01

    Nanomechanical properties of plasma-sprayed HfN coating with and without hot isostatic pressing (HIP) treatment were evaluated using nanoindentation. For HIPed HfN coating, the elastic modulus (E) and yield strength increase whereas the hardness (H), H/E ratio and fraction of the elastic work decrease. HIPed HfN coating shows a larger pile-up around the indent as compared to as-sprayed HfN. HIPing causes densification and improvement in inter-splat bonding which subsequently lead to increase in nanomechanical properties

  7. Porosity and wear resistance of flame sprayed tungsten carbide coatings

    Science.gov (United States)

    Winarto, Winarto; Sofyan, Nofrijon; Rooscote, Didi

    2017-06-01

    Thermal-sprayed coatings offer practical and economical solutions for corrosion and wear protection of components or tools. To improve the coating properties, heat treatment such as preheat is applied. The selection of coating and substrate materials is a key factor in improving the quality of the coating morphology after the heat treatment. This paper presents the experimental results regarding the effect of preheat temperatures, i.e. 200°C, 300°C and 400°C, on porosity and wear resistance of tungsten carbide (WC) coating sprayed by flame thermal coating. The powders and coatings morphology were analyzed by a Field Emission Scanning Electron Microscope equipped with Energy Dispersive Spectrometry (FE-SEM/EDS), whereas the phase identification was performed by X-Ray diffraction technique (XRD). In order to evaluate the quality of the flame spray obtained coatings, the porosity, micro-hardness and wear rate of the specimens was determined. The results showed that WC coating gives a higher surface hardness from 1391 HVN up to 1541 HVN compared to that of the non-coating. Moreover, the wear rate increased from 0.072 mm3/min. to 0.082 mm3/min. when preheat temperature was increased. Preheat on H13 steel substrate can reduce the percentage of porosity level from 10.24 % to 3.94% on the thermal spray coatings.

  8. Immobilisation of hydroxyapatite-collagen on polydopamine grafted stainless steel 316L: Coating adhesion and in vitro cells evaluation.

    Science.gov (United States)

    Tapsir, Zafirah; Jamaludin, Farah H; Pingguan-Murphy, Belinda; Saidin, Syafiqah

    2018-02-01

    The utilisation of hydroxyapatite and collagen as bioactive coating materials could enhance cells attachment, proliferation and osseointegration. However, most methods to form crystal hydroxyapatite coating do not allow the incorporation of polymer/organic compound due to production phase of high sintering temperature. In this study, a polydopamine film was used as an intermediate layer to immobilise hydroxyapatite-collagen without the introduction of high sintering temperature. The surface roughness, coating adhesion, bioactivity and osteoblast attachment on the hydroxyapatite-collagen coating were assessed as these properties remains unknown on the polydopamine grafted film. The coating was developed by grafting stainless steel 316L disks with a polydopamine film. Collagen type I fibres were then immobilised on the grafted film, followed by the biomineralisation of hydroxyapatite. The surface roughness and coating adhesion analyses were later performed by using AFM instrument. An Alamar Blue assay was used to determine the cytotoxicity of the coating, while an alkaline phosphatase activity test was conducted to evaluate the osteogenic differentiation of human fetal osteoblasts on the coating. Finally, the morphology of cells attachment on the coating was visualised under FESEM. The highest RMS roughness and coating adhesion were observed on the hydroxyapatite-collagen coating (hydroxyapatite-coll-dopa). The hydroxyapatite-coll-dopa coating was non-toxic to the osteoblast cells with greater cells proliferation, greater level of alkaline phosphate production and more cells attachment. These results indicate that the immobilisation of hydroxyapatite and collagen using an intermediate polydopamine is identical to enhance coating adhesion, osteoblast cells attachment, proliferation and differentiation, and thus could be implemented as a coating material on orthopaedic and dental implants.

  9. Preliminary evaluation of an aqueous wax emulsion for controlled-release coating.

    Science.gov (United States)

    Walia, P S; Stout, P J; Turton, R

    1998-02-01

    The purpose of this work was to evaluate the use of an aqueous carnauba wax emulsion (Primafresh HS, Johnson Wax) in a spray-coating process. This involved assessing the effectiveness of the wax in sustaining the release of the drug, theophylline. Second, the process by which the drug was released from the wax-coated pellets was modeled. Finally, a method to determine the optimum blend of pellets with different wax thicknesses, in order to yield a zero-order release profile of the drug, was addressed. Nonpareil pellets were loaded with theophylline using a novel powder coating technique. These drug-loaded pellets were then coated with different levels of carnauba wax in a 6-in. diameter Plexiglas fluid bed with a 3.5-in. diameter Wurster partition. Drug release was measured using a spin-filter dissolution device. The study resulted in continuous carnauba wax coatings which showed sustained drug release profile characteristics typical of a barrier-type, diffusion-controlled system. The effect of varying wax thickness on the release profiles was investigated. It was observed that very high wax loadings would be required to achieve long sustained-release times. The diffusion model, developed to predict the release of the drug, showed good agreement with the experimental data. However, the data exhibited an initial lag-time for drug release which could not be predicted a priori based on the wax coating thickness. A method of mixing pellets with different wax thicknesses was proposed as a way to approximate zero-order release.

  10. Effect of pulse current parameters on the mechanical and corrosion properties of anodized nanoporous aluminum coatings

    International Nuclear Information System (INIS)

    Mohammadi, Iman; Ahmadi, Shahab; Afshar, Abdollah

    2016-01-01

    In this study, the effects of pulse current parameters on corrosion resistance and mechanical properties of anodized coatings were evaluated. Hardness measurements, polarization and electrochemical impedance spectroscopy tests were employed to investigate the mechanical properties and corrosion behavior of these coatings. Also, field emission scanning electron microscopy (FE-SEM) was used to analyze the surface morphology and microstructure of the coatings. It was found that the properties of anodized coatings were dependent on various parameters, among which, time, temperature and pulse current parameters (current density limit, frequency and duty cycle) were optimized. Analysis of Variance (ANOVA) was conducted in order to optimize the results of designed experiments for predicting the hardness of anodic Al_2O_3 coatings. Experimental results showed that the temperature and the interaction of quadratic behavior of minimum current density with frequency and duty cycle were the most important factors influencing the hardness of these coatings. It was indicated that the highest hardness value of 642 HV was attained at the maximum and minimum current densities of 4.4, 1.27 A/dm"2, respectively, a frequency of 82 Hz, procedure time of 27.2 min, duty cycle of 80.2% and the bath temperature of 13.5 °C. In addition, the FE-SEM micrographs showed that the highest density is obtained through the mentioned optimum conditions. Moreover, the electrochemical tests revealed that the highest polarization resistance obtained at optimum conditions was more than 20 times greater than the other samples. - Highlights: • Electrolyte temperature undesirably influences the hardness of anodized coatings. • Maximum hardness of coatings was evaluated by optimization of effective parameters. • The diameter of alumina nanotube considerably affects hardness of anodized coating. • R_P of the sample formed at optimum condition was at least 20 times more than others. • Porosity is the

  11. Effect of pulse current parameters on the mechanical and corrosion properties of anodized nanoporous aluminum coatings

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Iman, E-mail: imanmohammadi68@gmail.com; Ahmadi, Shahab; Afshar, Abdollah

    2016-11-01

    In this study, the effects of pulse current parameters on corrosion resistance and mechanical properties of anodized coatings were evaluated. Hardness measurements, polarization and electrochemical impedance spectroscopy tests were employed to investigate the mechanical properties and corrosion behavior of these coatings. Also, field emission scanning electron microscopy (FE-SEM) was used to analyze the surface morphology and microstructure of the coatings. It was found that the properties of anodized coatings were dependent on various parameters, among which, time, temperature and pulse current parameters (current density limit, frequency and duty cycle) were optimized. Analysis of Variance (ANOVA) was conducted in order to optimize the results of designed experiments for predicting the hardness of anodic Al{sub 2}O{sub 3} coatings. Experimental results showed that the temperature and the interaction of quadratic behavior of minimum current density with frequency and duty cycle were the most important factors influencing the hardness of these coatings. It was indicated that the highest hardness value of 642 HV was attained at the maximum and minimum current densities of 4.4, 1.27 A/dm{sup 2}, respectively, a frequency of 82 Hz, procedure time of 27.2 min, duty cycle of 80.2% and the bath temperature of 13.5 °C. In addition, the FE-SEM micrographs showed that the highest density is obtained through the mentioned optimum conditions. Moreover, the electrochemical tests revealed that the highest polarization resistance obtained at optimum conditions was more than 20 times greater than the other samples. - Highlights: • Electrolyte temperature undesirably influences the hardness of anodized coatings. • Maximum hardness of coatings was evaluated by optimization of effective parameters. • The diameter of alumina nanotube considerably affects hardness of anodized coating. • R{sub P} of the sample formed at optimum condition was at least 20 times more than others

  12. An evaluation of the electric arc spray and (HPPS) processes for the manufacturing of high power plasma spraying MCrAIY coatings

    Science.gov (United States)

    Sacriste, D.; Goubot, N.; Dhers, J.; Ducos, M.; Vardelle, A.

    2001-06-01

    The high power plasma torch (PlazJet) can be used to spray refractory ceramics with high spray rates and deposition efficiency. It can provide dense and hard coating with high bond strengths. When manufacturing thermal barrier coatings, the PlazJet gun is well adapted to spraying the ceramic top coat but not the MCrAIY materials that are used as bond coat. Arc spraying can compete with plasma spraying for metallic coatings since cored wires can be used to spray alloys and composites. In addition, the high production rate of arc spraying enables a significant decrease in coating cost. This paper discusses the performances of the PlazJet gun, and a twin-wire are spray system, and compares the properties and cost of MCrAIY coatings made with these two processes. For arc spraying, the use of air or nitrogen as atomizing gas is also investigated.

  13. Evaluation of bonding strength between yttria coating and vanadium alloys for development of self-cooled blanket

    Energy Technology Data Exchange (ETDEWEB)

    Akamatsu, Hitoshi, E-mail: akamatsu@jupiter.qse.tohoku.ac.jp [Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2, Aramaki-aza-Aoba, Sendai 980-8579 (Japan); Satou, Manabu; Sato, Takashi [Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2, Aramaki-aza-Aoba, Sendai 980-8579 (Japan); Jain, Amit; Gupta, Vijay [Department of Mechanical and Aerospace Engineering, 38-137E, Eng IV Building, University of California, Los Angels, CA 90095-1597 (United States); Hasegawa, Akira [Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2, Aramaki-aza-Aoba, Sendai 980-8579 (Japan)

    2011-10-01

    A laser spallation technique was utilized for measurement of the bonding strength between yttria coating and vanadium alloys. The bonding strength between the alloys containing small amounts of yttrium made by levitation melting method and the yttria coating prepared by vacuum plasma-spray was evaluated to be about 950 MPa. It was not clearly observed the effects of alloying elements on the bonding strength. The strength varied about 100 MPa by specimens and by alloy compositions. Detailed observation of the failure type at the interface indicated that crack formation in the coating reduced the stress at the interface, so that the evaluation might be overestimated. It was demonstrated that application of the laser spallation technique to measure the bonding strength between ceramics coating and base material was useful for the evaluation of mechanical integrity of the coating.

  14. Evaluation of Thermal Barrier and PS-200 Self-Lubricating Coatings in an Air-Cooled Rotary Engine

    Science.gov (United States)

    Moller, Paul S.

    1995-01-01

    This project provides an evaluation of the feasibility and desirability of applying a thermal barrier coating overlaid with a wear coating on the internal surfaces of the combustion area of rotary engines. Many experiments were conducted with different combinations of coatings applied to engine components of aluminum, iron and titanium, and the engines were run on a well-instrumented test stand. Significant improvements in specific fuel consumption were achieved and the wear coating, PS-200, which was invented at NASA's Lewis Research Center, held up well under severe test conditions.

  15. Corrosion resistance and cytocompatibility of biodegradable surgical magnesium alloy coated with hydrogenated amorphous silicon.

    Science.gov (United States)

    Xin, Yunchang; Jiang, Jiang; Huo, Kaifu; Tang, Guoyi; Tian, Xiubo; Chu, Paul K

    2009-06-01

    The fast degradation rates in the physiological environment constitute the main limitation for the applications of surgical magnesium alloys as biodegradable hard-tissue implants. In this work, a stable and dense hydrogenated amorphous silicon coating (a-Si:H) with desirable bioactivity is deposited on AZ91 magnesium alloy using magnetron sputtering deposition. Raman spectroscopy and Fourier transform infrared spectroscopy reveal that the coating is mainly composed of hydrogenated amorphous silicon. The hardness of the coated alloy is enhanced significantly and the coating is quite hydrophilic as well. Potentiodynamic polarization results show that the corrosion resistance of the coated alloy is enhanced dramatically. In addition, the deterioration process of the coating in simulated body fluids is systematically investigated by open circuit potential evolution and electrochemical impedance spectroscopy. The cytocompatibility of the coated Mg is evaluated for the first time using hFOB1.19 cells and favorable biocompatibility is observed. 2008 Wiley Periodicals, Inc.

  16. On the evaluation of residual stress and mechanical properties of FeCrBSi coatings by nanoindentation

    International Nuclear Information System (INIS)

    Zhu Lina; Xu Binshi; Wang Haidou; Wang Chengbiao

    2012-01-01

    Highlights: ► Ni/Al coating can reduce the mismatch degree between the coating and substrate. ► No obvious pile-up is observed for the nanoindents of the FeCrBSi coating. ► The higher the tensile residual stress, the lower the hardness and elastic modulus. - Abstract: In this paper, the residual stress in the plasma-sprayed FeCrBSi coating was determined by nanoindentation and X-ray diffraction (XRD). The XRD results showed that tensile residual stress was generated in the FeCrBSi coating, and the through-thickness values range between 40 MPa and 112 MPa. The residual stress measured by nanoindentation is 753 MPa. The difference between the XRD and nanoindentation results was discussed. It is found that the factors limiting the nanoindentation measurement of residual stress include the ‘sink-in’ deformation around the indenter, the roughness of the FeCrBSi coating, and the use of reference sample without residual stress. The above three factors lead to the over-prediction of residual stress by nanoindentation.

  17. Wear Evaluation of AISI 4140 Alloy Steel with WC/C Lamellar Coatings Sliding Against EN 8 Using Taguchi Method

    Science.gov (United States)

    Kadam, Nikhil Rajendra; Karthikeyan, Ganesarethinam

    2016-10-01

    The purpose of the experiments in this paper is to use the Taguchi methods to investigate the wear of WC/C coated nitrided AISI 4140 alloy steel. A study of lamellar WC/C coating which were deposited by a physical vapor deposition on nitrided AISI 4140 alloy steel. The investigation includes wear evaluation using Pin-on-disk configuration. When WC/C coated AISI 4140 alloy steel slides against EN 8 steel, it was found that carbon-rich coatings show much lower wear of the countersurface than nitrogen-rich coatings. The results were correlated with the properties determined from tribological and mechanical characterization, therefore by probably selecting the proper processing parameters the deposition of WC/C coating results in decreasing the wear rate of the substrate which shows a potential for tribological application.

  18. Evaluating scintillator performance in time-resolved hard X-ray studies at synchrotron light sources

    International Nuclear Information System (INIS)

    Rutherford, Michael E.; Chapman, David J.; White, Thomas G.; Drakopoulos, Michael; Rack, Alexander; Eakins, Daniel E.

    2016-01-01

    Scintillator performance in time-resolved, hard, indirect detection X-ray studies on the sub-microsecond timescale at synchrotron light sources is reviewed, modelled and examined experimentally. LYSO:Ce is found to be the only commercially available crystal suitable for these experiments. The short pulse duration, small effective source size and high flux of synchrotron radiation is ideally suited for probing a wide range of transient deformation processes in materials under extreme conditions. In this paper, the challenges of high-resolution time-resolved indirect X-ray detection are reviewed in the context of dynamic synchrotron experiments. In particular, the discussion is targeted at two-dimensional integrating detector methods, such as those focused on dynamic radiography and diffraction experiments. The response of a scintillator to periodic synchrotron X-ray excitation is modelled and validated against experimental data collected at the Diamond Light Source (DLS) and European Synchrotron Radiation Facility (ESRF). An upper bound on the dynamic range accessible in a time-resolved experiment for a given bunch separation is calculated for a range of scintillators. New bunch structures are suggested for DLS and ESRF using the highest-performing commercially available crystal LYSO:Ce, allowing time-resolved experiments with an interframe time of 189 ns and a maximum dynamic range of 98 (6.6 bits)

  19. Evaluating scintillator performance in time-resolved hard X-ray studies at synchrotron light sources

    Energy Technology Data Exchange (ETDEWEB)

    Rutherford, Michael E.; Chapman, David J.; White, Thomas G. [Imperial College London, London (United Kingdom); Drakopoulos, Michael [Diamond Light Source, I12 Joint Engineering, Environmental, Processing (JEEP) Beamline, Didcot, Oxfordshire (United Kingdom); Rack, Alexander [European Synchrotron Radiation Facility, Grenoble (France); Eakins, Daniel E., E-mail: d.eakins@imperial.ac.uk [Imperial College London, London (United Kingdom)

    2016-03-24

    Scintillator performance in time-resolved, hard, indirect detection X-ray studies on the sub-microsecond timescale at synchrotron light sources is reviewed, modelled and examined experimentally. LYSO:Ce is found to be the only commercially available crystal suitable for these experiments. The short pulse duration, small effective source size and high flux of synchrotron radiation is ideally suited for probing a wide range of transient deformation processes in materials under extreme conditions. In this paper, the challenges of high-resolution time-resolved indirect X-ray detection are reviewed in the context of dynamic synchrotron experiments. In particular, the discussion is targeted at two-dimensional integrating detector methods, such as those focused on dynamic radiography and diffraction experiments. The response of a scintillator to periodic synchrotron X-ray excitation is modelled and validated against experimental data collected at the Diamond Light Source (DLS) and European Synchrotron Radiation Facility (ESRF). An upper bound on the dynamic range accessible in a time-resolved experiment for a given bunch separation is calculated for a range of scintillators. New bunch structures are suggested for DLS and ESRF using the highest-performing commercially available crystal LYSO:Ce, allowing time-resolved experiments with an interframe time of 189 ns and a maximum dynamic range of 98 (6.6 bits)

  20. Evaluating the Structure of Early English Literacy Skills in Deaf and Hard-of-Hearing Children.

    Science.gov (United States)

    Webb, Mi-Young; Lederberg, Amy R; Branum-Martin, Lee; McDonald Connor, Carol

    2015-10-01

    Better understanding the mechanisms underlying developing literacy has promoted the development of more effective reading interventions for typically developing children. Such knowledge may facilitate effective instruction of deaf and hard-of-hearing (DHH) children. Hence, the current study examined the multivariate associations among phonological awareness, alphabetic knowledge, word reading, and vocabulary skills in DHH children who have auditory access to speech. One hundred and sixty-seven DHH children (M age = 60.43 months) were assessed with a battery of early literacy measures. Forty-six percent used at least 1 cochlear implant; 54% were fitted with hearing aids. About a fourth of the sample was acquiring both spoken English and sign. Scores on standardized tests of phonological awareness and vocabulary averaged at least 1 standard deviation (SD) below the mean of the hearing norming sample. Confirmatory factor analyses showed that DHH children's early literacy skills were best characterized by a complex 3-factor model in which phonological awareness, alphabetic knowledge, and vocabulary formed 3 separate, but highly correlated constructs, with letter-sound knowledge and word reading skills relating to both phonological awareness and alphabetic knowledge. This supports the hypothesis that early reading of DHH children with functional hearing is qualitatively similar to that of hearing children. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Evaluating the Effects of Function-Based Interventions With Deaf or Hard-of-Hearing Students.

    Science.gov (United States)

    Gann, Candace J; Gaines, Sarah E; Antia, Shirin D; Umbreit, John; Liaupsin, Carl J

    2015-07-01

    This study examined the effectiveness of function-based interventions with students who are deaf or hard of hearing (D/HH). The participants were 3 elementary-aged males attending a center school for the deaf who exhibited chronic off-task behaviors throughout the school day. This study was conducted across 2 phases: (a) a descriptive functional behavior assessment (FBA) was conducted for each participant and (b) individualized function-based interventions were developed based on the results of the FBAs, followed by the implementation of the interventions in each classroom using a single-subject, ABAB reversal design. The function-based interventions significantly improved each participant's on-task behavior in his classroom environment. Furthermore, social validity ratings by each teacher revealed that the interventions were effective, easy to implement, and appropriate for each participant. Implications for application of the procedures used in this study with the D/HH population, limitations, and directions for future research are discussed. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Comparative examination of the microstructure and high temperature oxidation performance of NiCrBSi flame sprayed and pack cementation coatings

    Science.gov (United States)

    Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Skolianos, S.; Chrissafis, K.; Stergioudis, G.

    2009-01-01

    Coatings formed from NiCrBSi powder were deposited by thermal spray and pack cementation processes on low carbon steel. The microstructure and morphology of the coatings were studied by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Flame sprayed coatings exhibited high porosity and were mechanically bonded to the substrate while pack cementation coatings were more compact and chemically bonded to the substrate. The microhardness and the high temperature oxidation resistance of the coated samples were evaluated by a Vickers microhardness tester and by thermogravimetric measurements (TG), respectively. Pack cementation coatings showed higher hardness and were more protective to high temperature environments than the flame sprayed coatings.

  3. Abrasive Wear Resistance of the Iron- and WC-based Hardfaced Coatings Evaluated with Scratch Test Method

    Directory of Open Access Journals (Sweden)

    A. Vencl

    2013-06-01

    Full Text Available Abrasive wear is one of the most common types of wear, which makesabrasive wear resistance very important in many industries. Thehard facing is considered as useful and economical way to improve theperformance of components submitted to severe abrasive wear conditions, with wide range of applicable filler materials. The abrasive wear resistance of the three different hardfaced coatings (two iron‐based and one WC‐based, which were intended to be used for reparation of the impact plates of the ventilation mill, was investigated and compared. Abrasive wear tests were carried‐out by using the scratch tester under the dry conditions. Three normal loads of 10, 50 and 100 N and the constant sliding speed of 4 mm/s were used. Scratch test was chosen as a relatively easy and quick test method. Wear mechanism analysis showed significant influence of the hardfaced coatings structure, which, along with hardness, has determined coatings abrasive wear resistance.

  4. Dedicated outreach service for hard to reach patients with tuberculosis in London: observational study and economic evaluation.

    Science.gov (United States)

    Jit, Mark; Stagg, Helen R; Aldridge, Robert W; White, Peter J; Abubakar, Ibrahim

    2011-09-14

    To assess the cost effectiveness of the Find and Treat service for diagnosing and managing hard to reach individuals with active tuberculosis. Economic evaluation using a discrete, multiple age cohort, compartmental model of treated and untreated cases of active tuberculosis. London, United Kingdom. Population Hard to reach individuals with active pulmonary tuberculosis screened or managed by the Find and Treat service (48 mobile screening unit cases, 188 cases referred for case management support, and 180 cases referred for loss to follow-up), and 252 passively presenting controls from London's enhanced tuberculosis surveillance system. Incremental costs, quality adjusted life years (QALYs), and cost effectiveness ratios for the Find and Treat service. The model estimated that, on average, the Find and Treat service identifies 16 and manages 123 active cases of tuberculosis each year in hard to reach groups in London. The service has a net cost of £1.4 million/year and, under conservative assumptions, gains 220 QALYs. The incremental cost effectiveness ratio was £6400-£10,000/QALY gained (about €7300-€11,000 or $10,000-$16 000 in September 2011). The two Find and Treat components were also cost effective, even in unfavourable scenarios (mobile screening unit (for undiagnosed cases), £18,000-£26,000/QALY gained; case management support team, £4100-£6800/QALY gained). Both the screening and case management components of the Find and Treat service are likely to be cost effective in London. The cost effectiveness of the mobile screening unit in particular could be even greater than estimated, in view of the secondary effects of infection transmission and development of antibiotic resistance.

  5. Infrared spectroscopy, nano-mechanical properties, and scratch resistance of esthetic orthodontic coated archwires.

    Science.gov (United States)

    da Silva, Dayanne Lopes; Santos, Emanuel; Camargo, Sérgio de Souza; Ruellas, Antônio Carlos de Oliveira

    2015-09-01

    To evaluate the material composition, mechanical properties (hardness and elastic modulus), and scratch resistance of the coating of four commercialized esthetic orthodontic archwires. The coating composition of esthetic archwires was assessed by Fourier-transform infrared spectroscopy (FTIR). Coating hardness and elastic modulus were analyzed with instrumented nano-indentation tests. Scratch resistance of coatings was evaluated by scratch test. Coating micromorphologic characteristics after scratch tests were observed in a scanning electron microscope. Statistical differences were investigated using analysis of variance and Tukey post hoc test. The FTIR results indicate that all analyzed coatings were markedly characterized by the benzene peak at about 1500 cm(-1). The coating hardness and elastic modulus average values ranged from 0.17 to 0.23 GPa and from 5.0 to 7.6 GPa, respectively. Scratch test showed a high coating elasticity after load removal with elastic recoveries >60%, but different failure features could be observed along the scratches. The coatings of esthetic archwires evaluated are probably a composite of polyester and polytetrafluoroethylene. Delamination, crack propagation, and debris generation could be observed along the coating scratches and could influence its durability in the oral environment.

  6. Fabrication and biological evaluation of uniform extracellular matrix coatings on discontinuous photolithography generated micropallet arrays.

    Science.gov (United States)

    Gunn, Nicholas M; Bachman, Mark; Li, Guann-Pyng; Nelson, Edward L

    2010-11-01

    The recent identification of rare cell populations within tissues that are associated with specific biological behaviors, for example, progenitor cells, has illuminated a limitation of current technologies to study such adherent cells directly from primary tissues. The micropallet array is a recently developed technology designed to address this limitation by virtue of its capacity to isolate and recover single adherent cells on individual micropallets. The capacity to apply this technology to primary tissues and cells with restricted growth characteristics, particularly adhesion requirements, is critically dependent on the capacity to generate functional extracellular matrix (ECM) coatings. The discontinuous nature of the micropallet array surface provides specific constraints on the processes for generating the desired ECM coatings that are necessary to achieve the full functional capacity of the micropallet array. We have developed strategies, reported herein, to generate functional coatings with various ECM protein components: fibronectin, EHS tumor basement membrane extract, collagen, and laminin-5; confirmed by evaluation for rapid cellular adherence of four dissimilar cell types: fibroblast, breast epithelial, pancreatic epithelial, and myeloma. These findings are important for the dissemination and expanded use of micropallet arrays and similar microtechnologies requiring the integrated use of ECM protein coatings to promote cellular adherence.

  7. Evaluation of hardness, tribological behaviour and impact load of carbon-based hard composite coatings exposed to the influence of humidity

    Czech Academy of Sciences Publication Activity Database

    Sobota, Jaroslav; Grossman, Jan; Buršíková, V.; Dupák, Libor; Vyskočil, J.

    2011-01-01

    Roč. 20, č. 4 (2011), s. 596-599 ISSN 0925-9635 R&D Projects: GA MPO 2A-1TP1/031; GA ČR GA202/07/1669 Institutional research plan: CEZ:AV0Z20650511 Keywords : diamond-like carbon * mechanical properties * tribology Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 1.913, year: 2011

  8. Velocity Measurement of ultrasonic for evaluation of aging epoxy coating in containment structure of nuclear power plant

    International Nuclear Information System (INIS)

    Eun, Gil Soo; Kim, Noh Yu; Nah, Hwan Seon; Song, Young Chol

    2001-01-01

    Relative variation of ultrasonic velocity in aging epoxy coating in nuclear plant is measured for evaluation of the degradation of the epoxy coating. Time delay for ultrasound to travel through the epoxy film due to change of ultrasonic velocity is measured indirectly using ultrasonic interferometry which compares two reflection waves from the same point of coating surface at two different distances. Magnitude of the difference of two waves increases or decreases depending on change of the time of flight of ultrasound in the epoxy film caused by heat damage in the epoxy coating. Based on the transfer functions of the wedge and the epoxy coating in frequency domain, the reflection wave is analyzed and related to the velocity of ultrasound in the epoxy coating. A specially designed conical wedge is adopted to minimize the waviness effect of the surface of the epoxy coating. Epoxy films are fabricated, degraded under the accelerated aging conditions and tested to evaluate the change of ultrasonic velocity in the films. The experimental results show that the method can be applied to evaluate quantitatively the sealing quality of the epoxy coating.

  9. Coatings and Corrosion Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose: The mission of the Coatings and Corrosion Laboratory is to develop and analyze the effectiveness of innovative coatings test procedures while evaluating the...

  10. Metallographic techniques for evaluation of Thermal Barrier Coatings produced by Electron Beam Physical Vapor Deposition

    International Nuclear Information System (INIS)

    Kelly, Matthew; Singh, Jogender; Todd, Judith; Copley, Steven; Wolfe, Douglas

    2008-01-01

    Thermal Barrier Coatings (TBC) produced by Electron Beam Physical Vapor Deposition (EB-PVD) are primarily applied to critical hot section turbine components. EB-PVD TBC for turbine applications exhibit a complicated structure of porous ceramic columns separated by voids that offers mechanical compliance. Currently there are no standard evaluation methods for evaluating EB-PVD TBC structure quantitatively. This paper proposes a metallographic method for preparing samples and evaluating techniques to quantitatively measure structure. TBC samples were produced and evaluated with the proposed metallographic technique and digital image analysis for columnar grain size and relative intercolumnar porosity. Incorporation of the proposed evaluation technique will increase knowledge of the relation between processing parameters and material properties by incorporating a structural link. Application of this evaluation method will directly benefit areas of quality control, microstructural model development, and reduced development time for process scaling

  11. Evaluation of the relation between lipid coat, transepidermal water loss, and skin pH.

    Science.gov (United States)

    Algiert-Zielińska, Barbara; Batory, Mirella; Skubalski, Janusz; Rotsztejn, Helena

    2017-11-01

    The epidermis is an epidermal barrier which accumulates lipid substances and participates in skin moisturizing. An evaluation of the epidermal barrier efficiency can be made, among others, by the measurement of the following values: the lipid coat, the transepidermal water loss (TEWL) index, and pH. The study involved 50 Caucasian, healthy women aged 19-35 years (mean 20.56). Measurements were made using Courage & Khazaka Multi Probe Adapter MPA 580: Tewameter TM 300, pH-Meter PH 905, Sebumeter SM 815. The areas of measurements included forehead, nose, left cheek, right cheek, chin, and thigh. In the T-zone, the lipid coat was in the range between 0 and 270 μg/cm 2 (mean 128 μg/cm 2 ), TEWL between 1 and 55 g/m 2 /h (mean 11.1 g/m 2 /h), and pH 4.0-5.6 (mean 5.39). Lower values of the lipid coat up to 100 μg/cm 2 were accompanied by TEWL greater than 30 g/m 2 /h and less acidic pH of 5.6-9.0. In the U-zone the range of lipid coat was up to 200 μg/cm 2 (mean 65.2 μg/cm 2 ), the skin pH remained 4.0-5.6 (mean 5.47), and TEWL was in the range between 1 and 20 g/m 2 /h (mean 8.7 g/m 2 /h). Lower values of the lipid coat up to 100 μg/cm 2 were accompanied by TEWL between 1 and 20 g/m 2 /h and less acidic pH of 5.6-9.0. High values of the lipid coat between 180 and 200 μg/cm 2 were connected with TEWL of 1-15 g/m 2 /h. On the skin of the thigh, we observed a very thin lipid coat - 35 μg/cm 2 (mean 5.6 μg/cm 2 ), pH (mean 5.37), and TEWL (mean 8.5 g/m 2 /h) were considered by us to be within regular limits. In the T-zone, a thinner lipid coat resulted in relatively high TEWL and pH levels changing toward alkaline. In the U-zone, thinner lipid coat was accompanied by lower TEWL and pH changing toward alkaline. We also observed that lower values of lipid coat up to 100 μg/cm 2 were associated with higher pH values ranging toward the basic character pH 5.6-9.0). © 2017 The International Society of Dermatology.

  12. In vivo evaluation of the bone integration of coated poly(vinyl-alcohol) hydrogel fiber implants.

    Science.gov (United States)

    Moreau, David; Villain, Arthur; Bachy, Manon; Proudhon, Henry; Ku, David N; Hannouche, Didier; Petite, Hervé; Corté, Laurent

    2017-08-01

    Recently, it has been shown that constructs of poly(vinyl alcohol) (PVA) hydrogel fibers reproduce closely the tensile behavior of ligaments. However, the biological response to these systems has not been explored yet. Here, we report the first in vivo evaluation of these implants and focus on the integration in bone, using a rabbit model of bone tunnel healing. Implants consisted in bundles of PVA hydrogel fibers embedded in a PVA hydrogel matrix. Half of the samples were coated with a composite coating of hydroxyapatite (HA) particles embedded in PVA hydrogel. The biological integration was evaluated at 6 weeks using histology and micro-CT imaging. For all implants, a good biological tolerance and growth of new bone tissue are reported. All the implants were surrounded by a fibrous layer comparable to what was previously observed for poly(ethylene terephthalate) (PET) fibers currently used in humans for ligament reconstruction. An image analysis method is proposed to quantify the thickness of this fibrous capsule. Implants coated with HA were not significantly osteoconductive, which can be attributed to the slow dissolution of the selected hydroxyapatite. Overall, these results confirm the relevance of PVA hydrogel fibers for ligament reconstruction and adjustments are proposed to enhance its osseointegration.

  13. Evaluation of a dehumidifier with adsorbent coated heat exchangers for tropical climate operations

    KAUST Repository

    Oh, Seung Jin

    2017-03-10

    This paper presents the evaluation of a solid desiccant dehumidifier equipped with adsorbent powder coated heat exchangers (PCHX). The main component of the solid desiccant dehumidifier includes two heat exchangers that are coated with silica gel RD type powders in order to increase water adsorption uptake by improving its heat and mass transfer. A series of experiment are conducted to evaluate two key performance indices, namely, moisture removal capacity (MRC) and thermal coefficient performance (COPth), under various hot and humid air conditions. Conventional granular adsorbent packed heat exchangers (GPHX) are employed to benchmark the performance of the adsorbent coated heat exchanger (PCHX). Results reveal that the PCHX exhibits higher uptake performance due to better heat and mass transfer. It is found that the moisture removal capacity increases from 7.4 g/kg to 11.0 g/kg with air flow rates of 35 kg/h, resulting in the extended contact time of the water vapor. Experiments also demonstrate that the moisture removal capacity is highly affected by inlet air humidity ratio. In addition, marked improvement in COPth can be achieved by a lowered hot water regeneration temperature.

  14. Evaluation of a dehumidifier with adsorbent coated heat exchangers for tropical climate operations

    KAUST Repository

    Oh, Seung Jin; Ng, Kim Choon; Chun, Wongee; Chua, Kian Jon Ernest

    2017-01-01

    This paper presents the evaluation of a solid desiccant dehumidifier equipped with adsorbent powder coated heat exchangers (PCHX). The main component of the solid desiccant dehumidifier includes two heat exchangers that are coated with silica gel RD type powders in order to increase water adsorption uptake by improving its heat and mass transfer. A series of experiment are conducted to evaluate two key performance indices, namely, moisture removal capacity (MRC) and thermal coefficient performance (COPth), under various hot and humid air conditions. Conventional granular adsorbent packed heat exchangers (GPHX) are employed to benchmark the performance of the adsorbent coated heat exchanger (PCHX). Results reveal that the PCHX exhibits higher uptake performance due to better heat and mass transfer. It is found that the moisture removal capacity increases from 7.4 g/kg to 11.0 g/kg with air flow rates of 35 kg/h, resulting in the extended contact time of the water vapor. Experiments also demonstrate that the moisture removal capacity is highly affected by inlet air humidity ratio. In addition, marked improvement in COPth can be achieved by a lowered hot water regeneration temperature.

  15. Erosion of wind turbine blade coatings - Design and analysis of jet-based laboratory equipment for performance evaluation

    DEFF Research Database (Denmark)

    Zhang, Shizhong; Dam-Johansen, Kim; Nørkjær, Sten

    2015-01-01

    of the blades in such equipment. To reduce expensive blade maintenance repairs and to avoid out-of-service periods, energy-absorbing blade coatings are required to protect rotor blades from rain erosion. In this work we describe the design, construction and evaluation of a laboratory setup for fast screening...... experimental blade coatings were investigated using the proposed experimental design. The evaluation of the coatings under conditions where impact frequency and water hammer pressure were "matched" could not be directly correlated with the results obtained with the whirling arm rig. This result may...

  16. Evaluation of resistance of diamond-like carbon coating to the corpuscular radiation in outer space conditions

    Science.gov (United States)

    Tomilova, Elizaveta; Bashkov, Valeriy; Mikhalev, Pavel; Fedorchenko, Alexander; Volkova, Yana

    2015-02-01

    The purpose of this work was to research the resistance of thin coatings to the effects of corpuscular radiation, as well as evaluation speed etching of diamond-like films with different content of diamond phase. There were two samples of monocrystalline silicon with DLC coating. To evaluate the resistance, two groups of grooves were etched on each sample. The depth was then measured to calculate a relative etching ratio of DLC coating. The resistance was determined to be four times that of silicon.

  17. Evaluation of elastic modulus and hardness of crop stalks cell walls by nano-indentation

    Science.gov (United States)

    Yan Wu; Siqun Wang; Dingguo Zhou; Cheng Xing; Yang Zhang; Zhiyong Cai

    2010-01-01

    Agricultural biomaterials such as crop stalks are natural sources of cellulosic fiber and have great potential as reinforced materials in bio-composites. In order to evaluate their potential as materials for reinforcement, the nano-mechanical properties of crop-stalk cell walls, i.e. those of cotton (Gossypium herbaceu) stalk, soybean (Glycine max) stalk, cassava (...

  18. Evaluation of accelerated test parameters for CMOS IC total dose hardness prediction

    International Nuclear Information System (INIS)

    Sogoyan, A.V.; Nikiforov, A.Y.; Chumakov, A.I.

    1999-01-01

    The approach to accelerated test parameters evaluation is presented in order to predict CMOS IC total dose behavior in variable dose-rate environment. The technique is based on the analytical model of MOSFET parameters total dose degradation. The simple way to estimate model parameter is proposed using IC's input-output MOSFET radiation test results. (authors)

  19. Contact Behavior of Composite CrTiSiN Coated Dies in Compressing of Mg Alloy Sheets under High Pressure

    Directory of Open Access Journals (Sweden)

    T.S. Yang

    2018-01-01

    Full Text Available Hard coatings have been adopted in cutting and forming applications for nearly two decades. The major purpose of using hard coatings is to reduce the friction coefficient between contact surfaces, to increase strength, toughness and anti-wear performance of working tools and molds, and then to obtain a smooth work surface and an increase in service life of tools and molds. In this report, we deposited a composite CrTiSiN hard coating, and a traditional single-layered TiAlN coating as a reference. Then, the coatings were comparatively studied by a series of tests. A field emission SEM was used to characterize the microstructure. Hardness was measured using a nano-indentation tester. Adhesion of coatings was evaluated using a Rockwell C hardness indentation tester. A pin-on-disk wear tester with WC balls as sliding counterparts was used to determine the wear properties. A self-designed compression and friction tester, by combining a Universal Testing Machine and a wear tester, was used to evaluate the contact behavior of composite CrTiSiN coated dies in compressing of Mg alloy sheets under high pressure. The results indicated that the hardness of composite CrTiSiN coating was lower than that of the TiAlN coating. However, the CrTiSiN coating showed better anti-wear performance. The CrTiSiN coated dies achieved smooth surfaces on the Mg alloy sheet in the compressing test and lower friction coefficient in the friction test, as compared with the TiAlN coating.

  20. Contact Behavior of Composite CrTiSiN Coated Dies in Compressing of Mg Alloy Sheets under High Pressure.

    Science.gov (United States)

    Yang, T S; Yao, S H; Chang, Y Y; Deng, J H

    2018-01-08

    Hard coatings have been adopted in cutting and forming applications for nearly two decades. The major purpose of using hard coatings is to reduce the friction coefficient between contact surfaces, to increase strength, toughness and anti-wear performance of working tools and molds, and then to obtain a smooth work surface and an increase in service life of tools and molds. In this report, we deposited a composite CrTiSiN hard coating, and a traditional single-layered TiAlN coating as a reference. Then, the coatings were comparatively studied by a series of tests. A field emission SEM was used to characterize the microstructure. Hardness was measured using a nano-indentation tester. Adhesion of coatings was evaluated using a Rockwell C hardness indentation tester. A pin-on-disk wear tester with WC balls as sliding counterparts was used to determine the wear properties. A self-designed compression and friction tester, by combining a Universal Testing Machine and a wear tester, was used to evaluate the contact behavior of composite CrTiSiN coated dies in compressing of Mg alloy sheets under high pressure. The results indicated that the hardness of composite CrTiSiN coating was lower than that of the TiAlN coating. However, the CrTiSiN coating showed better anti-wear performance. The CrTiSiN coated dies achieved smooth surfaces on the Mg alloy sheet in the compressing test and lower friction coefficient in the friction test, as compared with the TiAlN coating.

  1. TECHNICAL EVALUATION OF THE SAFE TRANSPORTATION OF WASTE CONTAINERS COATED WITH POLYUREA

    Energy Technology Data Exchange (ETDEWEB)

    VAIL, T.S.

    2007-03-30

    This technical report is to evaluate and establish that the transportation of waste containers (e.g. drums, wooden boxes, fiberglass-reinforced plywood (FRP) or metal boxes, tanks, casks, or other containers) that have an external application of polyurea coating between facilities on the Hanford Site can be achieved with a level of onsite safety equivalent to that achieved offsite. Utilizing the parameters, requirements, limitations, and controls described in the DOE/RL-2001-36, ''Hanford Sitewide Transportation Safety Document'' (TSD) and the Department of Energy Richland Operations (DOE-RL) approved package specific authorizations (e.g. Package Specific Safety Documents (PSSDs), One-Time Requests for Shipment (OTRSs), and Special Packaging Authorizations (SPAS)), this evaluation concludes that polyurea coatings on packages does not impose an undue hazard for normal and accident conditions. The transportation of all packages on the Hanford Site must comply with the transportation safety basis documents for that packaging system. Compliance with the requirements, limitations, or controls described in the safety basis for a package system will not be relaxed or modified because of the application of polyurea. The inspection criteria described in facility/projects procedures and work packages that ensure compliance with Container Management Programs and transportation safety basis documentation dictate the need to overpack a package without consideration for polyurea. This technical report reviews the transportation of waste packages coated with polyurea and does not credit the polyurea with enhancing the structural, thermal, containment, shielding, criticality, or gas generating posture of a package. Facilities/Projects Container Management Programs must determine if a container requires an overpack prior to the polyurea application recognizing that circumstances newly discovered surface contamination or loss of integrity may require a previously

  2. TECHNICAL EVALUATION OF THE SAFE TRANSPORTATION OF WASTE CONTAINERS COATED WITH POLYUREA

    International Nuclear Information System (INIS)

    VAIL, T.S.

    2007-01-01

    This technical report is to evaluate and establish that the transportation of waste containers (e.g. drums, wooden boxes, fiberglass-reinforced plywood (FRP) or metal boxes, tanks, casks, or other containers) that have an external application of polyurea coating between facilities on the Hanford Site can be achieved with a level of onsite safety equivalent to that achieved offsite. Utilizing the parameters, requirements, limitations, and controls described in the DOE/RL-2001-36, ''Hanford Sitewide Transportation Safety Document'' (TSD) and the Department of Energy Richland Operations (DOE-RL) approved package specific authorizations (e.g. Package Specific Safety Documents (PSSDs), One-Time Requests for Shipment (OTRSs), and Special Packaging Authorizations (SPAS)), this evaluation concludes that polyurea coatings on packages does not impose an undue hazard for normal and accident conditions. The transportation of all packages on the Hanford Site must comply with the transportation safety basis documents for that packaging system. Compliance with the requirements, limitations, or controls described in the safety basis for a package system will not be relaxed or modified because of the application of polyurea. The inspection criteria described in facility/projects procedures and work packages that ensure compliance with Container Management Programs and transportation safety basis documentation dictate the need to overpack a package without consideration for polyurea. This technical report reviews the transportation of waste packages coated with polyurea and does not credit the polyurea with enhancing the structural, thermal, containment, shielding, criticality, or gas generating posture of a package. Facilities/Projects Container Management Programs must determine if a container requires an overpack prior to the polyurea application recognizing that circumstances newly discovered surface contamination or loss of integrity may require a previously un

  3. Nanašanje trdih zaščitnih prevlek s katodnim lokom: Cathodic arc plasma deposition of hard protective coatings:

    OpenAIRE

    Panjan, Peter

    2002-01-01

    The cathodic arc evaporation process is based upon the vacuum arc, the physics of which is still under investigation. This method is using almost exclusively for the deposition of wear-resistant coatings onto cutting and forming tools. The method is fast, effective, and relatively cost efficient. This paper reviews the arc evaporation process. Naparevanje s katodnim lokom temelji na plazemskem loku, ki ga prižegmo v vakuumu. Postopek se uporablja skoraj izključno za pripravo trdih zaščitni...

  4. Nano-hardness estimation by means of Ar{sup +} ion etching

    Energy Technology Data Exchange (ETDEWEB)

    Bartali, R., E-mail: bartali@fbk.eu; Micheli, V.; Gottardi, G.; Vaccari, A.; Safeen, M.K.; Laidani, N.

    2015-08-31

    When the coatings are in nano-scale, the mechanical properties cannot be easily estimated by means of the conventional methods due to: tip shape, instrument resolution, roughness, and substrate effect. In this paper, we proposed a semi-empirical method to evaluate the mechanical properties of thin films based on the sputtering rate induced by bombardment of Ar{sup +} ion. The Ar{sup +} ion bombardment was induced by ion gun implemented in Auger electron spectroscopy (AES). This procedure has been applied on a series of coatings with different structure (carbon films) and a series of coating with a different density (ZnO thin films). The coatings were deposited on Silicon substrates by RF sputtering plasma. The results show that, as predicted by Insepov et al., there is a correlation between hardness and sputtering rate. Using reference materials and a simple power law equation the estimation of the nano-hardness using an Ar{sup +} beam is possible. - Highlights: • ZnO film and Carbon films were grown on silicon using PVD. • The growth temperature was room temperature. • The hardness of the coatings was estimated by means of nanoindentation. • Evaluation of resistance of materials to the mechanical damage induced by an Ar{sup +} ion gun (AES). • The hardness have been studied and a power law with the erosion rate has been found.

  5. A Study on Performance Evaluation of Safety-Related Protective Coating for Yonggwang Unit 1 and 2

    International Nuclear Information System (INIS)

    Kim, Sung Young; Kim, Young Bum; Lee, Won Sang

    2010-01-01

    Protective coating inside nuclear power plants could find its origin from NRC Reg. Guide 1.82(Rev. 3) regarding current issue for the regulation of foreign materials inside containment building. The current issue for the regulation of foreign materials inside containment considered/determined the current issues only regarding the blockage of sump screen by foreign materials such as coating material, insulator, and other materials, while safety-related coating is separately managed by NRC Reg. Guide 1.54(Rev. 1). In this study, we performed field walk-down to evaluate the as-is condition of protective coating inside containment building which was classified as for structure and for equipment with applying the requirement for safety-related coating

  6. Coating of Bio-mimetic Minerals-Substituted Hydroxyapatite on Surgical Grade Stainless Steel 316L by Electrophoretic Deposition for Hard tissue Applications

    Science.gov (United States)

    Govindaraj, Dharman; Rajan, Mariappan

    2018-02-01

    Third-era bio-implant materials intend to empower particular live cell reactions at the atomic level, these materials represented with a resorbable and biocompatibility that bodies recuperate once they have been embedded. Necessitate to decrease expenses in public health services has required the utilization of surgical grade stainless steel (SS 316L) as the most inexpensive choice for orthodontic and orthopaedic implants. 316L SS is one of the broadly used implant biomaterials in orthodontic and orthopaedic surgeries. Yet, frequently those discharge for toxic metal ions is confirm from the implants and hence a second surgery is required will remove those implant material. One approach to managing the discharge of toxic metal ions is to coat the implant substance with bio-mimetic minerals in hydroxyapatite (HA). Bio-mimetic minerals such as magnesium (Mg), strontium (Sr), also zinc (Zn) were revealed with animate bone growth furthermore restrain bone resorption both in vitro and in vivo. The present work deals with the electrophoretic deposition (EPD) for multi minerals substituted hydroxyapatite (M-HA) on the surface treated 316L SS under distinctive temperatures (27°C, (room temperature), 60 and 80°C). The resultant coatings were characterized by FT-IR, XRD, SEM-EDX, adhesion strength and leach out analysis.

  7. Evaluation of tribological wear and corrosion in coatings of diamalloy 4060NS deposited by thermal spray

    Science.gov (United States)

    Acuña R, S. M.; Moreno T, C. M.; Espinosa C, E. J.

    2017-12-01

    Surface engineering seeks the development of new techniques to improve the performance and life of components of machines or industrial facilities, always looking for low costs and the least possible environmental damage. Thermal projection is one of the techniques that is based on the projection of particles of compounds and alloys on properly prepared and heated substrates, these particles are driven by a stream of air passing through an oxyacetylene flame which gives the energy to the process; These coatings give the possibility to improve the properties of the materials or the maintenance of components to maximize the availability of service. In order to reduce the damage caused by wear and corrosion of a low carbon AISI 1020 steel, they were coated with a metal based alloy, studying the effect of the cobalt-chromium-silicon-tungsten carbide alloy coating (DIAMALLLOY 4060 NS). The coating was deposited with two different pressures in the gases supplied to the torch, obtaining two flames and working three thicknesses of coating that oscillate between 100-500μm, according to the number of deposited layers, making use of a projection gun Castolin Eutectic. Powder and substrate characterization was performed using X-Ray Diffraction (XRD) techniques, X-Ray Fluorescence (XRF), Scanning Electron Microscopy (SEM), spark emission spectroscopy and metallographic analysis. The results confirm the chemical nature and structure of the powder of the alloy and the substrate to be used, in addition, the thermal stability of the system was verified. The evaluation of the adhesion of the deposited layers was carried out by the implementation of pull-off tests according to ASTM D4541, in order to determine the type of failure that is presented. Mechanical wear was determined using a MT/60/NI microtest tribometer while electrochemical tests were performed using a suitable experimental unit for this purpose, confirming that the substrate exhibits lower wear levels when coated with

  8. Preparation and in vitro evaluation of nanostructured TiO2/TCP composite coating by plasma electrolytic oxidation

    International Nuclear Information System (INIS)

    Hu, Hongjie; Liu, Xuanyong; Ding, Chuanxian

    2010-01-01

    Porous and nanostructured TiO 2 /tricalcium phosphate (TCP) composite coating on titanium substrate was prepared by plasma electrolytic oxidation (PEO). The microstructure and phase composition of the coating were characterized using scanning electron microscopy and X-ray diffraction. Its bioactivity was evaluated by simulated body fluid (SBF) immersion tests. MG63 cells were cultured on the surface of the coating to investigate its cytocompatibility. Potentiodynamic polarization tests were applied to measure its corrosion resistance. The results revealed that rough and hydrophilic TiO 2 /TCP composite coating with pores of several micrometers and grains of 50-200 nm was prepared by one-step PEO treatment. The TiO 2 /TCP composite coating showed good apatite-forming ability in SBF, and the TCP phase in the coating played an important role in inducing apatite formation. MG63 cells could adhere and proliferate on the surface of the coating, indicating its good cytocompatibility. The composite coating also exhibited good corrosion resistance in 0.9% NaCl solution.

  9. Evaluation of the biocompatibility of a coating material for an implantable bladder volume sensor

    Directory of Open Access Journals (Sweden)

    Su-Jin Kim

    2012-03-01

    Full Text Available As the applications for implantable medical devices have increased, the need for biocompatible packaging materials has become important. Recently, we reported an implantable sensor for real-time monitoring of the changes in bladder volume, which necessitated finding a safe coating material for use in bladder tissue. At present, materials like polyethylene glycol (PEG, polydimethylsiloxane (PDMS and parylene-C are used in biomedical devices or as coating materials, owing to their excellent safety in various medical fields. However, few studies have assessed their safety in bladder tissue, therefore, we evaluated the biocompatibility of PEG, PDMS and parylene-C in the bladder. All three materials turned out to be safe in in vitro tests of live/dead staining and cell viability. In vivo tests with hematoxylin and eosin and immunofluorescence staining with MAC387 showed no persistent inflammation. Therefore, we consider that the three materials are biocompatible in bladder tissue. Despite this safety, however, PEG has biodegradable characteristics and thus is not suitable for use as packaging. We suggest that PDMS and parylene-C can be used as safe coating materials for the implantable bladder volume sensor reported previously.

  10. Preparation and Evaluation of Newly Developed Chitosan Salt Coating Dispersions for Colon Delivery without Requiring Overcoating.

    Science.gov (United States)

    Yamada, Kyohei; Iwao, Yasunori; Bani-Jaber, Ahmad; Noguchi, Shuji; Itai, Shigeru

    2015-01-01

    Although chitosan (CS) has been recognized as a good material for colon-specific drug delivery systems, an overcoating with an enteric coating polymer on the surface of CS is absolutely necessary because CS is soluble in acidic conditions before reaching the colon. In the present study, to improve its stability in the presence of acid, a newly developed CS-laurate (CS-LA) material was evaluated as a coating dispersion for the development of colon-specific drug delivery systems. Two types of CS with different molecular weights, CS250 and CS600, were used to prepare CS-LA films by the casting method. The CS250-LA films had smooth surfaces, whereas the surfaces of the CS600-LA films were rough, indicating that the CS250-LA dispersion could form a denser film than CS600-LA. Both of these CS-LA films maintained a constant shape over 22 h in a pH 1.2 HCl/NaCl buffer, where the corresponding CS films rapidly disintegrated. In addition, the CS250-LA film showed specific colon degradability in a pH 6.0 phosphate buffered solution containing 1.0% (w/v) β-glucosidase. As a result of tensile strength and elongation at the break, both CS-LA films were found to have flexible film properties. Finally, the release of acetaminophen from disks coated with CS250-LA dispersions was significantly suppressed in fluids at pH 1.2 and 6.8, whereas disks coated with CS solution rapidly released the drug in pH 1.2 fluids. Taken together, this study shows that LA modification could be a useful approach in preparing CS films with acid stability and colonic degradability properties without requiring overcoating.

  11. Development and evaluation of a dimensionless mechanistic pan coating model for the prediction of coated tablet appearance.

    Science.gov (United States)

    Niblett, Daniel; Porter, Stuart; Reynolds, Gavin; Morgan, Tomos; Greenamoyer, Jennifer; Hach, Ronald; Sido, Stephanie; Karan, Kapish; Gabbott, Ian

    2017-08-07

    A mathematical, mechanistic tablet film-coating model has been developed for pharmaceutical pan coating systems based on the mechanisms of atomisation, tablet bed movement and droplet drying with the main purpose of predicting tablet appearance quality. Two dimensionless quantities were used to characterise the product properties and operating parameters: the dimensionless Spray Flux (relating to area coverage of the spray droplets) and the Niblett Number (relating to the time available for drying of coating droplets). The Niblett Number is the ratio between the time a droplet needs to dry under given thermodynamic conditions and the time available for the droplet while on the surface of the tablet bed. The time available for drying on the tablet bed surface is critical for appearance quality. These two dimensionless quantities were used to select process parameters for a set of 22 coating experiments, performed over a wide range of multivariate process parameters. The dimensionless Regime Map created can be used to visualise the effect of interacting process parameters on overall tablet appearance quality and defects such as picking and logo bridging. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Evaluation of residual stresses in welded part using hard synchrotron x-rays

    International Nuclear Information System (INIS)

    Suzuki, Kenji; Shobu, Takahisa; Shiro, Ayumi; Zhang Shuoyuan

    2013-01-01

    The spiral slit-system and DSTM (diffraction spot trace method) are under development in order to evaluate internal stresses of materials with coarse grains. The spiral slit-system was improved so that the length of the gauge volume is independent of the diffraction angle. The bending stress in the specimen with coarse grains was measured in order to confirm performance of this advanced spiral slit-system. The distribution of the measured bending stress coincided with the applied bending stress. As a result, it was proved that the combination of the advanced spiral slit-system and the DSTM is useful for the internal stress measurement of materials with coarse grains. The welded specimen of a Mg-alloy plate was prepared by melt-run with TIG welding. The residual stress map in the cross-section of the specimen was made using the DSTM. On the other hand, the residual stresses of the welded specimen were simulated by a finite element method. Although the measured residual stresses were similar to the simulated results, the residual stresses due to extrusion were measured also using the DSTM. The DSTM is an excellent technique for the stress measurement of weld parts. (author)

  13. Evaluating the effect of coating equipment on tablet film quality using terahertz pulsed imaging

    DEFF Research Database (Denmark)

    Haaser, Miriam; Naelapaa, Kaisa; Gordon, Keith C

    2013-01-01

    In this study, terahertz pulsed imaging (TPI) was employed to investigate the effect of the coating equipment (fluid bed and drum coater) on the structure of the applied film coating and subsequent dissolution behaviour. Six tablets from every batch coated with the same delayed release coating fo...

  14. Effect of the metal concentration on the structural, mechanical and tribological properties of self-organized a-C:Cu hard nanocomposite coatings

    International Nuclear Information System (INIS)

    Pardo, A.; Buijnsters, J.G.; Endrino, J.L.; Gómez-Aleixandre, C.; Abrasonis, G.; Bonet, R.; Caro, J.

    2013-01-01

    The influence of the metal content (Cu: 0–28 at.%) on the structural, mechanical and tribological properties of amorphous carbon films grown by pulsed filtered cathodic vacuum arc deposition is investigated. Silicon and AISI 301 stainless steel have been used as substrate materials. The microstructure, composition and bonding structure have been determined by scanning electron microscopy, combined Rutherford backscattered spectroscopy-nuclear reaction analysis, and Raman spectroscopy, respectively. The mechanical and tribological properties have been assessed using nanoindentation and reciprocating sliding (fretting tests) and these have been correlated with the elemental composition of the films. A self-organized multilayered structure consisting of alternating carbon and copper metal nanolayers (thickness in the 25–50 nm range), whose formation is enhanced by the Cu content, is detected. The nanohardness and Young’s modulus decrease monotonically with increasing Cu content. A maximum value of the Young’s modulus of about 255 GPa is obtained for the metal-free film, whereas it drops to about 174 GPa for the film with a Cu content of 28 at.%. In parallel, a 50% drop in the nanohardness from about 28 GPa towards 14 GPa is observed for these coatings. An increase in the Cu content also produces an increment of the coefficient of friction in reciprocating sliding tests performed against a corundum ball counterbody. As compared to the metal free film, a nearly four times higher coefficient of friction value is detected in the case of a Cu content of 28 at.%. Nevertheless, the carbon–copper composite coatings produced a clear surface protection of the substrate despite an overall increase in wear loss with increasing Cu content in the range 3–28 at.%.

  15. Effect of the metal concentration on the structural, mechanical and tribological properties of self-organized a-C:Cu hard nanocomposite coatings

    Science.gov (United States)

    Pardo, A.; Buijnsters, J. G.; Endrino, J. L.; Gómez-Aleixandre, C.; Abrasonis, G.; Bonet, R.; Caro, J.

    2013-09-01

    The influence of the metal content (Cu: 0-28 at.%) on the structural, mechanical and tribological properties of amorphous carbon films grown by pulsed filtered cathodic vacuum arc deposition is investigated. Silicon and AISI 301 stainless steel have been used as substrate materials. The microstructure, composition and bonding structure have been determined by scanning electron microscopy, combined Rutherford backscattered spectroscopy-nuclear reaction analysis, and Raman spectroscopy, respectively. The mechanical and tribological properties have been assessed using nanoindentation and reciprocating sliding (fretting tests) and these have been correlated with the elemental composition of the films. A self-organized multilayered structure consisting of alternating carbon and copper metal nanolayers (thickness in the 25-50 nm range), whose formation is enhanced by the Cu content, is detected. The nanohardness and Young’s modulus decrease monotonically with increasing Cu content. A maximum value of the Young’s modulus of about 255 GPa is obtained for the metal-free film, whereas it drops to about 174 GPa for the film with a Cu content of 28 at.%. In parallel, a 50% drop in the nanohardness from about 28 GPa towards 14 GPa is observed for these coatings. An increase in the Cu content also produces an increment of the coefficient of friction in reciprocating sliding tests performed against a corundum ball counterbody. As compared to the metal free film, a nearly four times higher coefficient of friction value is detected in the case of a Cu content of 28 at.%. Nevertheless, the carbon-copper composite coatings produced a clear surface protection of the substrate despite an overall increase in wear loss with increasing Cu content in the range 3-28 at.%.

  16. Evaluation of atmospheric corrosion on electroplated zinc and zinc nickel coatings by Electrical Resistance (ER) Monitoring

    DEFF Research Database (Denmark)

    Møller, Per

    2013-01-01

    ER (Electrical Resistance) probes provide a measurement of metal loss, measured at any time when a metal is exposed to the real environment. The precise electrical resistance monitoring system can evaluate the corrosion to the level of nanometers, if the conductivity is compensated for temperature...... and magnetic fields. With this technique very important information about the durability of a new conversion coatings for aluminum, zinc and zinc alloys exposed to unknown atmospheric conditions can be gathered. This is expected to have a major impact on a number of industrial segments, such as test cars...

  17. The evaluation of Computed Tomography hard- and software tools for micropaleontologic studies on foraminifera

    Science.gov (United States)

    van Loo, D.; Speijer, R.; Masschaele, B.; Dierick, M.; Cnudde, V.; Boone, M.; de Witte, Y.; Dewanckele, J.; van Hoorebeke, L.; Jacobs, P.

    2009-04-01

    Foraminifera (Forams) are single-celled amoeba-like organisms in the sea, which build a tiny calcareous multi-chambered shell for protection. Their enormous abundance, great variation of shape through time and their presence in all marine deposits made these tiny microfossils the oil companies' best friend by facilitating the detection of new oil wells. Besides the success of forams in the oil and gas industry, they are also a most powerful tool for reconstructing climate change in the past. The shell of a foraminifer is a tiny gold mine of information both geometrical as chemical. However, until recently the best information on this architecture was only obtained through imaging the outside of a shell with Scanning Electron Microscopy (SEM), giving no clues towards internal structures other than single snapshots through breaking a specimen apart. With X-ray computed tomography (CT) it is possible to overcome this problem and uncover a huge amount of geometrical information without destructing the samples. Using the last generation of micro-CT's, called nano-CT, because of the sub-micron resolution, it is now possible to perform adequate imaging even on these tiny samples without needing huge facilities. In this research, a comparison is made between different X-ray sources and X-ray detectors and the resulting image resolution. Both sharpness, noise and contrast are very important parameters that will have important effects on the accuracy of the results and on the speed of data-processing. Combining this tomography technique with specific image processing software, called segmentation, it is possible to obtain a 3D virtual representation of the entire forams shell. This 3D virtual object can then be used for many purposes, from which automatic measurement of the chambers size is one of the most important ones. The segmentation process is a combination of several algorithms that are often used in CT evaluation, in this work an evaluation of those algorithms is

  18. Hardness evaluation of cured urea-formaldehyde resins with different formaldehyde/urea mole ratios using nanoindentation method

    Science.gov (United States)

    Byung-Dae Park; Charles R. Frihart; Yan Yu; Adya P. Singh

    2013-01-01

    To understand the influence of formaldehyde/urea (F/U) mole ratio on the properties of urea–formaldehyde (UF) resins, this study investigated hardness of cured UF resins with different F/U mole ratios using a nanoindentation method. The traditional Brinell hardness (HB) method was also used...

  19. EVALUATING THE ROLE OF ION COMPOSITION ON THE TOXICITY OF COPPER TO CERIODAPHNIA DUBIA IN VERY HARD WATERS

    Science.gov (United States)

    The mitigating effect of increasing hardness on metal toxicity is reflected in water quality criteria in the United States. - - - Copper toxicity did not consistently vary as a function of hardness, but likely as a function of other water quality characteristics (e.g. alkalinity ...

  20. Protective Coatings

    Science.gov (United States)

    1980-01-01

    General Magnaplate Corporation's pharmaceutical machine is used in the industry for high speed pressing of pills and capsules. Machine is automatic system for molding glycerine suppositories. These machines are typical of many types of drug production and packaging equipment whose metal parts are treated with space spinoff coatings that promote general machine efficiency and contribute to compliance with stringent federal sanitation codes for pharmaceutical manufacture. Collectively known as "synergistic" coatings, these dry lubricants are bonded to a variety of metals to form an extremely hard slippery surface with long lasting self lubrication. The coatings offer multiple advantages; they cannot chip, peel or be rubbed off. They protect machine parts from corrosion and wear longer, lowering maintenance cost and reduce undesired heat caused by power-robbing friction.

  1. Designing a highly sensitive Eddy current sensor for evaluating damage on thermal barrier coating

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Min; Kim, Hak Joon; Song, Sung Jin; Seok, Chang Seong; Lee, Yeong Ze [Dept. of Mechanical Engineering, Sungkyunkwan University, Suwon (Korea, Republic of); Lee, Seul Gi [LG Electronics, Seoul (Korea, Republic of)

    2016-06-15

    A thermal barrier coating (TBC) has been widely applied to machine components working under high temperature as a thermal insulator owing to its critical financial and safety benefits to the industry. However, the nondestructive evaluation of TBC damage is not easy since sensing of the microscopic change that occurs on the TBC is required during an evaluation. We designed an eddy current probe for evaluating damage on a TBC based on the finite element method (FEM) and validated its performance through an experiment. An FEM analysis predicted the sensitivity of the probe, showing that impedance change increases as the TBC thermally degrades. In addition, the effect of the magnetic shield concentrating magnetic flux density was also observed. Finally, experimental validation showed good agreement with the simulation result.

  2. Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period

    Directory of Open Access Journals (Sweden)

    Ugur Erdemir

    2013-04-01

    Full Text Available Objectives: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. Material and Methods: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group. For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05. Results: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (p<0.001 in different solutions (p<0.001. The effect of different solutions on the surface hardness values of the restorative materials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (p<0.001. The compomer was the most affected by an acidic environment, whereas the composite resin materials were the least affected materials. Conclusions: The effect of sports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material.

  3. Evaluation of the attachment, proliferation, and differentiation of osteoblast on a calcium carbonate coating on titanium surface

    Energy Technology Data Exchange (ETDEWEB)

    Liu Yi; Jiang Tao; Zhou Yi; Zhang Zhen; Wang Zhejun [Key Laboratory for Oral Biomedical Engineering, Ministry of Education, School and Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan 430079 (China); Tong Hua; Shen Xinyu [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Wang Yining, E-mail: wang.yn@whu.edu.cn [Key Laboratory for Oral Biomedical Engineering, Ministry of Education, School and Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan 430079 (China)

    2011-07-20

    Titanium has been reported to have some limitations in dental and orthopaedic clinical application. This study described a coating process using a simple chemical method to prepare calcium carbonate coatings on smooth titanium (STi) and sandblasted and acid-etched titanium (SATi), and evaluated the biological response of the materials in vitro. The surfaces of STi, SATi, calcium carbonate coated STi (CC-STi) and calcium carbonate coated SATi (CC-SATi) were characterized for surface roughness, contact angles, surface morphology and surface chemistry. The morphology of MG63 cells cultured on the surfaces was observed by SEM and Immuno-fluorescence staining. Cell attachment/proliferation was assessed by MTT assay, and cell differentiation was evaluated by alkaline phosphatase (ALP) activity. MG63 was found to attach favorably to calcium carbonate crystals with longer cytoplasmic extensions on CC-STi and CC-SATi, resulting in lower cell proliferation but higher ALP activity when compared to STi and SATi respectively. Moreover, CC-SATi is more favorable than CC-STi in terms of biological response. In conclusion, the calcium carbonate coatings on titanium were supposed to improve the osteointegration process and stimulate osteoblast differentiation, especially in early stage. And this method could possibly be a feasible alternative option for future clinical application. Highlights: {yields} Calcium carbonate coatings were prepared on titanium substrates. {yields} The coating process is simple and cost-effective. {yields} Calcium carbonate coating could induce differentiation toward an osteoblastic phenotype. {yields} Calcium carbonate coating could enhance the osteointegration process especially in early stage.

  4. In vitro color evaluation of esthetic coatings for metallic dental implants and implant prosthetic appliances.

    Science.gov (United States)

    Pecnik, Christina M; Roos, Malgorzata; Muff, Daniel; Spolenak, Ralph; Sailer, Irena

    2015-05-01

    The aim of this study was to characterize the optical properties of newly developed esthetic coatings for metallic implants and components for an improved peri-implant soft tissue appearance. Pig maxillae (n = 6) were used for the in vitro color evaluation of coated and uncoated samples. Three different coating systems (Ti-ZrO(2), Ti-Al-ZrO(2), and Ti-Ag-ZrO(2)) were deposited on titanium substrates, which exhibited different roughness (polished, machined, and sand-blasted) and interference colors (pink, yellow, and white). Spectrophotometric measurements were made of samples below three different mucosa thicknesses (1 mm, 2 mm, and 3 mm) and titanium served as negative control. Color difference ΔE was calculated using ΔL, Δa, and Δb values for each sample (in total 30 samples). ΔE values were significantly above the threshold value of 3.70 for sand-blasted Ti and Ti-ZrO(2) samples when tested below 1 mm thick soft tissue, hence resulted in a dark appearance of the soft tissues. In contrast, Ti-Al-ZrO(2) and Ti-Ag-ZrO(2) samples showed significant ΔL values below 1 mm, which indicates a brightening of the covering tissue. In general, ΔE values decreased with increasing thickness of the tissue. At 3 mm thick tissue, ΔE values were significantly below 3.70 for Ti-Al-ZrO(2) and Ti-Ag-ZrO(2) samples. The preferable substrate surface should be machined due increased color brightness, good soft tissue integration and improved adhesion between coating and substrates. Improvement of the optical appearance of the metal was achieved with the coating systems Ti-Al-ZrO(2) and Ti-Ag-ZrO(2). Darkening effects could not be observed for these systems, and partially light brightening of the tissue was observed. Advantageous colors were suggested to be pink and yellow. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Evaluation and Comparison of the Effects of RRA, T73 and T6 Heat Treatments on Hardness, Tensile and Bending Strengths of 7075 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    M. Assadi

    2016-09-01

    20 min and in the third stage aging process was repeated like T6 treatment. Evaluation of the microstructures and fractured surfaces were performed with optical microscopes (OM and scanning electron microscopes (SEM. Energy dispersive spectroscopy (EDS was used to study the chemical composition of precipitates. Hardness, tensile and bending strength were evaluated according to ASTM E384-11e1, ASTM B557-06 and DIN 50121 standards. RRA treatment increased tensile strength from 466 to 485 MPa and hardness from 110 to 165 Vickers. After T6 treatment, tensile strength increased from 466 to 505 MPa and hardness from 110 to 160 Vickers. In T73 process, the tensile strength remained almost constant (465 MPa but yield strength increased from 394 to 410 MPa and hardness decreased from 110 to 84 Vickers. The bending strength increased from 797 to 844, 920 and 1030 MPa in T73, RRA and T6 processes, respectively. By applying RRA process in optimized temperature and time, hardness, tensile and bending strengths of 7075 aluminum alloy were enhanced from 5 to 15% compared to that of T6 and T73 processes.

  6. 7 CFR 201.57 - Hard seeds.

    Science.gov (United States)

    2010-01-01

    ... REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at the end of the prescribed test because they have not absorbed water, due to an impermeable seed coat... percentage of germination. For flatpea, continue the swollen seed in test for 14 days when germinating at 15...

  7. Evaluation of radiation tolerance of FETs used for Astro-E2 hard X-ray detector (HXD-II)

    International Nuclear Information System (INIS)

    Itoh, Takeshi; Niko, Hisako; Kokubun, Motohide; Makishima, Kazuo; Kawaharada, Madoka; Takahashi, Isao; Miyasaka, Hiromasa

    2005-01-01

    We evaluated the radiation tolerance of three types of metal-can MOS Field Effect Transistors (FETs). They are candidates for flight electronics of the Hard X-ray Detector (HXD-II) experiment which is onboard the cosmic X-ray satellite Astro-E2 scheduled for launch in 2005. We irradiated FETs with a Co60γ-ray source under several different experimental conditions, and measured changes in their I-V characteristic curves. After a 10krad irradiation during which the gate voltage is set at 0V, all types showed a decrease in the switching voltage by ∼0.2-0.4V. In addition, the gate conductance increased under some irradiation conditions. These experimental results may be explained in terms of trapped charges and boundary levels in the oxide layer beneath the gate electrode. We have confirmed that at least two types of FETs can be used in our satellite-borne experiment, one as relay-driving FETs and the other in TTL-ECL conversion circuits

  8. Comparative characterization of Cu–Ni substrates for coated conductors

    DEFF Research Database (Denmark)

    Tian, H.; Suo, H.L.; Wulff, Anders Christian

    2014-01-01

    Three Cu100xNix alloys, with x = 23, 33 and 45 at.%Ni, have been evaluated for use as substrates for coated conductors on the basis of measurements of their microstructure, crystallographic texture and hardness. It is found that high-temperature annealing after heavy rolling generates strong cube...

  9. Biomimetic novel nanoporous niobium oxide coating for orthopaedic applications

    Science.gov (United States)

    Pauline, S. Anne; Rajendran, N.

    2014-01-01

    Niobium oxide was synthesized by sol-gel methodology and a crystalline, nanoporous and adherent coating of Nb2O5 was deposited on 316L SS using the spin coating technique and heat treatment. The synthesis conditions were optimized to obtain a nanoporous morphology. The coating was characterized using attenuated total reflectance-Infrared spectroscopy (ATR-IR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM) and transmission electron microscopy (TEM) and the formation of crystalline Nb2O5 coating with nanoporous morphology was confirmed. Mechanical studies confirmed that the coating has excellent adherence to the substrate and the hardness value of the coating was excellent. Contact angle analysis showed increased hydrophilicity for the coated substrate. In vitro bioactivity test confirmed that the Nb2O5 coating with nanoporous morphology facilitated the growth of hydroxyapatite (HAp). This was further confirmed by the solution analysis test where increased uptake of calcium and phosphorous ions from simulated body fluid (SBF) was observed. Electrochemical evaluation of the coating confirmed that the crystalline coating is insulative and protective in nature and offered excellent corrosion protection to 316L SS. Thus, this study confirmed that the nanoporous crystalline Nb2O5 coating conferred bioactivity and enhanced corrosion resistance on 316L SS.

  10. Biomimetic novel nanoporous niobium oxide coating for orthopaedic applications

    Energy Technology Data Exchange (ETDEWEB)

    Pauline, S. Anne; Rajendran, N., E-mail: nrajendran@annauniv.edu

    2014-01-30

    Niobium oxide was synthesized by sol–gel methodology and a crystalline, nanoporous and adherent coating of Nb{sub 2}O{sub 5} was deposited on 316L SS using the spin coating technique and heat treatment. The synthesis conditions were optimized to obtain a nanoporous morphology. The coating was characterized using attenuated total reflectance-Infrared spectroscopy (ATR-IR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM) and transmission electron microscopy (TEM) and the formation of crystalline Nb{sub 2}O{sub 5} coating with nanoporous morphology was confirmed. Mechanical studies confirmed that the coating has excellent adherence to the substrate and the hardness value of the coating was excellent. Contact angle analysis showed increased hydrophilicity for the coated substrate. In vitro bioactivity test confirmed that the Nb{sub 2}O{sub 5} coating with nanoporous morphology facilitated the growth of hydroxyapatite (HAp). This was further confirmed by the solution analysis test where increased uptake of calcium and phosphorous ions from simulated body fluid (SBF) was observed. Electrochemical evaluation of the coating confirmed that the crystalline coating is insulative and protective in nature and offered excellent corrosion protection to 316L SS. Thus, this study confirmed that the nanoporous crystalline Nb{sub 2}O{sub 5} coating conferred bioactivity and enhanced corrosion resistance on 316L SS.

  11. Replacement for a Flex Hose Coating at the Space Shuttle Launch Pad

    Science.gov (United States)

    Whitten, Mary; Vinje, Rubiela; Curran, Jerome; Meneghelli, Barry; Calle, Luz Marina

    2009-01-01

    Aerocoat AR-7 is a coating that has been used to protect stainless steel flex hoses at NASA's Kennedy Space Center launch complex and hydraulic lines of the mobile launch platform (MLP). This coating has great corrosion control performance and low temperature application. AR-7 was developed by NASA and produced exclusively for NASA but its production has been discontinued due to its high content of volatile organic compounds (VOC) and significant environmental impact. The purpose of this project was to select and evaluate candidate coatings to find a replacement coating that is more environmentally friendly, with similar properties to AR-7. No coatings were identified that perform the same as AR-7 in all areas. Candidate coatings failed in comparison to AR-7 in salt fog, beachside atmospheric exposure, pencil hardness, Mandrel bend, chemical compatibility, adhesion, and ease of application tests. However, two coatings were selected for further evaluation.

  12. Corrosion properties of zirconium-based ceramic coatings for micro-bearing and biomedical applications

    International Nuclear Information System (INIS)

    Walkowicz, J; Zavaleyev, V; Dobruchowska, E; Murzynski, D; Donkov, N; Zykova, A; Safonov, V; Yakovin, S

    2016-01-01

    Ceramic oxide ZrO 2 and oxynitride ZrON coatings are widely used as protective coatings against diffusion and corrosion. The enhancement of the coatings' mechanical properties, as well as their wear and corrosion resistance, is very important for their tribological performance. In this work, ZrO 2 and ZrON coatings were deposited by magnetron sputtering on stainless steel (AISI 316) substrates. The adhesion, hardness and elastic properties were evaluated by standard methods. The surface structure of the deposited coatings was observed by electron scanning microscopy (SEM) and atomic force microscopy (AFM). The composition of the coatings was analyzed by X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDS). The corrosion resistance properties were evaluated using the potentiodynamic method. The results show that the corrosion parameters are significantly increased in the cases of both oxynitride and oxide coatings in comparison with the stainless steel (AISI 316) substrates. (paper)

  13. Corrosion properties of zirconium-based ceramic coatings for micro-bearing and biomedical applications

    Science.gov (United States)

    Walkowicz, J.; Zavaleyev, V.; Dobruchowska, E.; Murzynski, D.; Donkov, N.; Zykova, A.; Safonov, V.; Yakovin, S.

    2016-03-01

    Ceramic oxide ZrO2 and oxynitride ZrON coatings are widely used as protective coatings against diffusion and corrosion. The enhancement of the coatings' mechanical properties, as well as their wear and corrosion resistance, is very important for their tribological performance. In this work, ZrO2 and ZrON coatings were deposited by magnetron sputtering on stainless steel (AISI 316) substrates. The adhesion, hardness and elastic properties were evaluated by standard methods. The surface structure of the deposited coatings was observed by electron scanning microscopy (SEM) and atomic force microscopy (AFM). The composition of the coatings was analyzed by X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDS). The corrosion resistance properties were evaluated using the potentiodynamic method. The results show that the corrosion parameters are significantly increased in the cases of both oxynitride and oxide coatings in comparison with the stainless steel (AISI 316) substrates.

  14. Electrochemical evaluation of corrosion and tribocorrosion behaviour of amorphous and nanocrystalline cobalt–tungsten electrodeposited coatings

    Energy Technology Data Exchange (ETDEWEB)

    Fathollahzade, N.; Raeissi, K., E-mail: k_raeissi@cc.iut.ac.ir

    2014-11-14

    Amorphous and nanocrystalline Co–W coatings were electrodeposited on copper substrates from a citrate–ammonia bath. The coatings showed nodular surface morphologies, but a microcrack network was detected in the amorphous coating. However, a better corrosion resistance was achieved for the amorphous coating. During sliding under open circuit potential (OCP) condition, the potential of amorphous coating gradually became more active probably due to the widening of wear scar, and thus expansion of active area. The amorphous coatings showed a higher volume loss at OCP probably due to its lower microhardness. In anodic sliding, a sharp increase in current density was observed due to mass transport and depassivation effects. In all sliding conditions, the proportion of mass transport was higher than wear accelerated corrosion, which implied that the dissolution reaction of the coatings was mainly a mass-transport controlled process. The results also showed that the effect of sliding on degradation is more intense for the nanocrystalline coating. For both coatings, the formation of the superficial microcracks in the vicinity of wear scars indicating on a surface fatigue wear mechanism. - Highlights: • Mass-transport effect had higher proportion in tribocorrosion of Co–W coatings. • The major electrochemical-wear degradation was for the nanocrystalline coating. • The higher proportion of wear accelerated corrosion was for the amorphous coating. • Superficial microcracks were formed near scars due to the coatings brittleness.

  15. Nanoporous Aluminum Oxide Membranes Coated with Atomic Layer Deposition-Grown Titanium Dioxide for Biomedical Applications: An In Vitro Evaluation.

    Science.gov (United States)

    Petrochenko, Peter E; Kumar, Girish; Fu, Wujun; Zhang, Qin; Zheng, Jiwen; Liang, Chengdu; Goering, Peter L; Narayan, Roger J

    2015-12-01

    The surface topographies of nanoporous anodic aluminum oxide (AAO) and titanium dioxide (TiO2) membranes have been shown to modulate cell response in orthopedic and skin wound repair applications. In this study, we: (1) demonstrate an improved atomic layer deposition (ALD) method for coating the porous structures of 20, 100, and 200 nm pore diameter AAO with nanometer-thick layers of TiO2 and (2) evaluate the effects of uncoated AAO and TiO2-coated AAO on cellular responses. The TiO2 coatings were deposited on the AAO membranes without compromising the openings of the nanoscale pores. The 20 nm TiO2-coated membranes showed the highest amount of initial protein adsorption via the micro bicinchoninic acid (micro-BCA) assay; all of the TiO2-coated membranes showed slightly higher protein adsorption than the uncoated control materials. Cell viability, proliferation, and inflammatory responses on the TiO2-coated AAO membranes showed no adverse outcomes. For all of the tested surfaces, normal increases in proliferation (DNA content) of L929 fibroblasts were observed over from 4 hours to 72 hours. No increases in TNF-alpha production were seen in RAW 264.7 macrophages grown on TiO2-coated AAO membranes compared to uncoated AAO membranes and tissue culture polystyrene (TCPS) surfaces. Both uncoated AAO membranes and TiO2-coated AAO membranes showed no significant effects on cell growth and inflammatory responses. The results suggest that TiO2-coated AAO may serve as a reasonable prototype material for the development of nanostructured wound repair devices and orthopedic implants.

  16. Material Evaluation and Process Optimization of CNT-Coated Polymer Powders for Selective Laser Sintering

    Directory of Open Access Journals (Sweden)

    Shangqin Yuan

    2016-10-01

    Full Text Available Multi-walled carbon nanotubes (CNTs as nano-reinforcements were introduced to facilitate the laser sintering process and enhance the thermal and mechanical properties of polymeric composites. A dual experimental-theoretical method was proposed to evaluate the processability and predict the process parameters of newly developed CNT-coated polyamide 12 (CNTs/PA12 powders. The thermal conductivity, melt viscosity, phase transition and temperature-dependent density and heat capacity of PA12 and CNTs/PA12 powders were characterized for material evaluation. The composite powders exhibited improved heat conduction and heat absorption compared with virgin polymer powders, and the stable sintering range of composite powders was extended and found to be favourable for the sintering process. The microstructures of sintered composites revealed that the CNTs remained at the powder boundaries and formed network architectures, which instantaneously induced the significant enhancements in tensile strength, elongation at break and toughness without sacrificing tensile modulus.

  17. A vacuum thermogravimetric method for outgassing evaluations of silicone-coated fiberglass cloth

    Science.gov (United States)

    Jensen, L. B.; Mccauley, G. B.; Honma, M.; Hultquist, A. E.

    1972-01-01

    A method for evaluating outgassing characteristics of space-sensitive materials was devised by modifying a thermogravimetric balance so that a continual weight loss trace is obtained as a function of time at constant temperature and nearly constant pressure. In addition the apparatus is capable of collecting room temperature condensibles during the outgassing run. A series of silicone-coated glass cloth samples were evaluated by this method. The major advantage of the technique is that data presentation is developed in the form of a continuous trace. This data can then be utilized to develop the kinetics of weight loss. The technique has been shown to be a useful and valid one for indicating small differences between materials under vacuum and elevated temperature conditions.

  18. Evaluation of corrosion behaviour of tantalum coating obtained by low pressure chemical vapor deposition using electrochemical polarization

    Science.gov (United States)

    Levesque, A.; Bouteville, A.; de Baynast, H.; Laveissière, B.

    2002-06-01

    antalum coatings are elaborated on titanium substrates through Low Pressure Chemical Vapor Deposition from tantalum pentachloride-hydrogen gaseous phase at a deposition temperature of 800 °C and a total pressure of 3.3 mbar. The aim of this paper is to evaluate the effectiveness of this tantalum coating in corrosive solution. Optical Microscopy and Scanning Electron Microscopy observations reveal that deposits are of 1.7 μm in thickness and conformal. The corrosion resistance of tantalum coated titanium substrates is quantified through standard potentiodynamic polarization method. Even for tantalum coatings exhibiting some defects as pores, the corrosion current density is as low as 0.25 mA/cm^2.in very agressive solutions like kroll reagent (HN03/HF).

  19. The in vitro indirect cytotoxicity test and in vivo interface bioactivity evaluation of biodegradable FHA coated Mg-Zn alloys

    Energy Technology Data Exchange (ETDEWEB)

    Li Jianan [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Han Pei, E-mail: hanpei_cn@163.com [Orthopaedic Department of the 6th People' s Hospital, Shanghai Jiao Tong University, Shanghai 200233 (China); Ji Weiping [Orthopaedic Department of the 6th People' s Hospital, Shanghai Jiao Tong University, Shanghai 200233 (China); Song, Yang; Zhang, Shaoxiang; Chen Ying; Zhao Changli; Zhang Fan [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhang Xiaonong, E-mail: xnzhang@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Key Laboratory of Inorganic Coating Materials, Chinese Academy of Sciences, Shanghai 200051 (China); Jiang Yao [Orthopaedic Department of the 6th People' s Hospital, Shanghai Jiao Tong University, Shanghai 200233 (China)

    2011-12-15

    A kind of biodegradable fluoridated hydroxyapatite (FHA) coating was prepared on Mg-Zn alloy to improve the interface bioactivity in bone healing via electrodeposition method. The in vitro cytotoxicity evaluation of the ions released during degradation was taken. No toxicity was shown and even higher cells' viability appeared on the 7th day compared with the normal culture case (negative control). In vivo implantation was carried out in the femoral condyle of adult New Zealand rabbits. The cross section showed by Micro-CT scan confirmed that the better interface contacts happened in the coated group after one month implantation. Also the coating left can still be normally observed by scanning electron microscope (SEM) with a little degradation. As a result, the FHA coating may be a promising candidate to enhance interface bioactivity for biodegradable Mg alloys in orthopaedics.

  20. Attenuation characteristics of seismic motion based on earthquake observation records. Identification of damping factor at hard rock sites and its influences on ground stability evaluation

    International Nuclear Information System (INIS)

    Sato, Hiroaki; Kanatani, Mamoru; Ohtori, Yasuki

    2005-01-01

    In this report, we examined validity of currently available ground stability evaluation method by applying commonly used damping factor which was invariant for frequency. First, we conducted a survey of the actual conditions of damping factors, which were used in ground stability evaluation, on 10 existing nuclear power plants. As a result, we found that damping factor of 0.03(3%) was used in of 80 percent investigated plants. Next, a spectral inversion method using very fast simulated annealing was proposed for identifying damping factor and its lower limit. Here, the lower limit of damping factor means intrinsic damping factor. The developed inversion method was applied to borehole array data recorded at hard rock ground. From the inversion, it was found that intrinsic damping factor of hard rock ground distributed between about 0.03(3%) and 0.06(3%) at a depth of less than 100m, and between about 0.003(0.3%) and 0.01(1%) at a depth of more than 100m. Furthermore, we indicated that scattering damping factor with in a depth of less than 100m was in proportion to the almost -1.0 power of the frequency, and the factor in a depth of more than 100m had a peak in a frequency range from about 1.0 to 5.0 Hz. Therefore, it was recognized that commonly used damping of 0.03(3%) expressed intrinsic damping factor of shallower hard rock ground. Finally, we estimated the influences of damping factor on ground stability evaluation by 2D dynamic FEM analyses of hard rock foundation ground considering 8 slipping lines using 6 combinations of damping factor. It was demonstrated that the variation of damping factor was not so decisive on the results of ground stability evaluation. This suggests present ground stability evaluation method by applying commonly used damping factor is reasonable for hard rock sites. (author)

  1. Preparation and in vitro evaluation of plasma-sprayed bioactive akermanite coatings

    International Nuclear Information System (INIS)

    Yi, Deliang; Wu, Chengtie; Chang, Jiang; Ma, Xubing; Ji, Heng; Zheng, Xuebin

    2012-01-01

    Bioactive ceramic coatings on titanium (Ti) alloys play an important role in orthopedic applications. In this study, akermanite (Ca 2 MgSi 2 O 7 ) bioactive coatings are prepared through a plasma spraying technique. The bonding strength between the coatings and Ti-6Al-4V substrates is around 38.7–42.2 MPa, which is higher than that of plasma sprayed hydroxyapatite (HA) coatings reported previously. The prepared akermanite coatings reveal a distinct apatite-mineralization ability in simulated body fluid. Furthermore, akermanite coatings support the attachment and proliferation of rabbit bone marrow mesenchymal stem cells (BMSCs). The proliferation rate of BMSCs on akermanite coatings is obviously higher than that on HA coatings. (paper)

  2. Development of coatings for ultrasonic additive manufacturing sonotrode using laser direct metal deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Niyanth S, Niyanth [ORNL; Dehoff, Ryan R [ORNL; Jordan, Brian H [ORNL; Babu, Sudarsanam Suresh [ORNL

    2016-10-01

    ORNL partnered with Fabrisonic, LLC to develop galling resistant hard facing coatings on sonotrodes used to fabricate 3D printed materials using ultrasonic additive manufacturing. The development and deployment of a coated sonotrode is expected to push the existing state of the art to facilitate the solidstate additive manufacturing of hard steels and titanium alloys. To this effect a structurally amorphous stainless steel material and cobalt chrome material were deposited on the sonotrode material. Both the deposits showed good adhesion to the substrate. The coatings made using the structurally amorphous steel materials showed cracking during the initial trials and cracking was eliminated by deposition on a preheated substrate. Both the coatings show hardness in excess of 600 HVN. Thus the phase 1 of this project has been used to identify suitable materials to use to coat the sonotrode. Despite the fact that successful deposits were obtained, the coatings need to be evaluated by performing detailed galling tests at various temperatures. In addition field tests are also necessary to test the stability of these coatings in a high cycle ultrasonic vibration mode. If awarded, phase 2 of the project would be used to optimize the composition of the deposit material to maximize galling resistance. The industrial partner would then use the coated sonotrode to fabricate builds made of austenitic stainless steel to test the viability of using a coated sonotrode.

  3. Analytical and Experimental Draft Force Evaluation of Plastic Coated Chisel Tines

    Directory of Open Access Journals (Sweden)

    M Barzegar Tabrizi

    2017-10-01

    Methods Eight tines have been built. Four of them had a thick coating layer of UHMW-PE, and the other four were made of pure mild steel. Each set of the tines have been installed on a four shanked chisel plough chassis and then attached to a tractor. The draft force required for pulling the furrowers attached to the tractor has been measured by a simple load meter mechanism connecting two tractors. Draft force has been measured in two different speeds. Slip ratio of the tractor has been recorded. Each test has been repeated three times.McKyes-Ali’s proposed model for evaluating the draft force of narrow blades has been chosen to predict draft force of the traditional steel furrower tines and the surface coated ones. To drive the model, a computer program has been coded in the script environment of Matlab software. The model required some of the mechanical properties of the soil and the tool to operate. Specific gravity, cohesion and internal friction angle of the soil have been measured by routine laboratory methods. Soil-tool adhesion and friction of the mild steel and the UHMW-PE plates have been measured using the direct shear apparatus. Results and Discussions MkKyes-Ali’s model has predicted draft forces with an accuracy of 90%. According to the results of the driven model, applying a UHMW-PE coating layer to the surface of the tines can improve draft force by 13%. The change of tractor speed from 3.5 km h-1 to 5.5 km h-1 have no significant effect on the predicted draft forces. The model also predicted different angles of the soil failure zone for coated and uncoated tines. On the other hand, the improvement of the draft force for the UHMW-PE coated tine in the field test was about 27%. According to The results obtained from the field test, the draft force of the furrower tines had significant correlation with the speed. Conclusions The UHMW-PE coated tines required significantly less draft force to work in compare with the steel tines. McKyes-Ali’s model

  4. Design and performance evaluation of the functional coating for air purification under indoor conditions

    NARCIS (Netherlands)

    Lorencik, S.; Yu, Q.L.; Brouwers, H.J.H.

    2015-01-01

    The present work aims to develop a photocatalytic coating for the improvement of indoor air quality. Two types of visible-light responsive photocatalysts (powder and suspension form) were applied into a water-based acrylic coating. The applied materials were characterized and the developed coatings

  5. Evaluating tamsulosin hydrochloride-released microparticles prepared using single-step matrix coating.

    Science.gov (United States)

    Maeda, Atsushi; Shinoda, Tatsuki; Ito, Naoki; Baba, Keizo; Oku, Naoto; Mizumoto, Takao

    2011-04-15

    The objective of the present study was to determine the optimum composition for sustained-release of tamsulosin hydrochloride from microparticles intended for orally disintegrating tablets. Microparticles were prepared from an aqueous ethylcellulose dispersion (Aquacoa®), and an aqueous copolymer based on ethyl acrylate and methyl methacrylate dispersion (Eudragit®) NE30D), with microcrystalline cellulose as core particles with a fluidized bed coating process. Prepared microparticles were about 200 μm diameter and spherical. The microparticles were evaluated for in vitro drug release and in vivo absorption to assess bioequivalence in a commercial product, Harnal® pellets. The optimum ratio of Aquacoat® and Eudragit® NE30D in the matrix was 9:1. We observed similar drug release profiles in microparticles and Harnal® pellets. Higuchi model analysis of the in vitro drug release from microparticles was linear up to 80% release, typical of Fickian diffusion sustained-release profile. The in vivo absorption properties from microparticles were comparable to Harnal® pellets, and there was a linear relationship between in vitro drug release and in vivo drug release. In conclusion, this development produces microparticles in single-step coating, that provided a sustained-release of tamsulosin hydrochloride comparable to Harnal® pellets. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Evaluation of commercial nickel-phosphorus coating for ultracold neutron guides using a pinhole bottling method

    Science.gov (United States)

    Pattie, R. W.; Adamek, E. R.; Brenner, T.; Brandt, A.; Broussard, L. J.; Callahan, N. B.; Clayton, S. M.; Cude-Woods, C.; Currie, S. A.; Geltenbort, P.; Ito, T. M.; Lauer, T.; Liu, C. Y.; Majewski, J.; Makela, M.; Masuda, Y.; Morris, C. L.; Ramsey, J. C.; Salvat, D. J.; Saunders, A.; Schroffenegger, J.; Tang, Z.; Wei, W.; Wang, Z.; Watkins, E.; Young, A. R.; Zeck, B. A.

    2017-11-01

    We report on the evaluation of commercial electroless nickel phosphorus (NiP) coatings for ultracold neutron (UCN) transport and storage. The material potential of 50 μm thick NiP coatings on stainless steel and aluminum substrates was measured to be VF = 213(5 . 2) neV using the time-of-flight spectrometer ASTERIX at the Lujan Center. The loss per bounce probability was measured in pinhole bottling experiments carried out at ultracold neutron sources at Los Alamos Neutron Science Center and the Institut Laue-Langevin. For these tests a new guide coupling design was used to minimize gaps between the guide sections. The observed UCN loss in the bottle was interpreted in terms of an energy independent effective loss per bounce, which is the appropriate model when gaps in the system and upscattering are the dominate loss mechanisms, yielding a loss per bounce of 1 . 3(1) × 10-4. We also present a detailed discussion of the pinhole bottling methodology and an energy dependent analysis of the experimental results.

  7. Standard Test Method for Mechanical Hydrogen Embrittlement Evaluation of Plating/Coating Processes and Service Environments

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method describes mechanical test methods and defines acceptance criteria for coating and plating processes that can cause hydrogen embrittlement in steels. Subsequent exposure to chemicals encountered in service environments, such as fluids, cleaning treatments or maintenance chemicals that come in contact with the plated/coated or bare surface of the steel, can also be evaluated. 1.2 This test method is not intended to measure the relative susceptibility of different steels. The relative susceptibility of different materials to hydrogen embrittlement may be determined in accordance with Test Method F1459 and Test Method F1624. 1.3 This test method specifies the use of air melted AISI E4340 steel per SAE AMS-S-5000 (formerly MIL-S-5000) heat treated to 260 – 280 ksi (pounds per square inch x 1000) as the baseline. This combination of alloy and heat treat level has been used for many years and a large database has been accumulated in the aerospace industry on its specific response to exposure...

  8. [Emission characteristics and safety evaluation of volatile organic compounds in manufacturing processes of automotive coatings].

    Science.gov (United States)

    Zeng, Pei-Yuan; Li, Jian-Jun; Liao, Dong-Qi; Tu, Xiang; Xu, Mei-Ying; Sun, Guo-Ping

    2013-12-01

    Emission characteristics of volatile organic compounds (VOCs) were investigated in an automotive coating manufacturing enterprise. Air samples were taken from eight different manufacturing areas in three workshops, and the species of VOCs and their concentrations were measured by gas chromatography-mass spectrometry (GC-MS). Safety evaluation was also conducted by comparing the concentration of VOCs with the permissible concentration-short term exposure limit (PC-STEL) regulated by the Ministry of Health. The results showed that fifteen VOCs were detected in the indoor air of the automotive coatings workshop, including benzene, toluene, ethylbenzene, xylene, ethyl acetate, butyl acetate, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, trimethylbenzene and ethylene glycol monobutyl ether, Their concentrations widely ranged from 0.51 to 593.14 mg x m(-3). The concentrations of TVOCs were significantly different among different manufacturing processes. Even in the same manufacturing process, the concentrations of each component measured at different times were also greatly different. The predominant VOCs of indoor air in the workshop were identified to be ethylbenzene and butyl acetate. The concentrations of most VOCs exceeded the occupational exposure limits, so the corresponding control measures should be taken to protect the health of the workers.

  9. Evaluation of the efficacy of insecticidal coatings based on teflutrin and chlorpyrifos against Rhynchophorus ferrugineus.

    Science.gov (United States)

    Pugliese, Massimo; Rettori, Andrea Alberto; Martinis, Roberto; Al-Rohily, Khalid; Velate, Suresh; Moideen, Mohamed Ashraf; Al-Maashi, Ali

    2017-08-01

    The date palm (Phoenix dactylifera L.), an important economic resource for many nations worldwide, has recently been threatened by the presence of different insect pests, like the red palm weevil (RPW) Rhynchophorus ferrugineus. Two products, a glue (polyvinyl acetate) and an oil (raw linseed oil) were used as coatings and applied together with a repellent and two insecticides (teflutrin and chlorpyrifos) at different dosages on two species of palm (P. dactylifera and P. canariensis). Phytotoxic effects of the treatments were evaluated in a greenhouse on 260 potted palms (130 P. dactylifera and 130 P. canariensis) and no negative effects were observed. Afterwards, a trial lasting 400 days was carried out in a nursery located in Sicily (south Italy), treating 572 potted palm trees (286 P. dactylifera and 286 P. canariensis) with an average diameter at the base of 18-20 cm. After 400 days, 48% of the untreated palms were infested, while only 3% of date palms and 7% of Canary palms treated with insecticide at lower dosages were infested. The application of an insecticide-based coating is a good strategy to control and prevent the red palm weevil infestation, in particular on date palms. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  10. Nanocomposite tribological coatings with 'chameleon' surface adaptation

    International Nuclear Information System (INIS)

    Voevodin, A.A.; Fitz, T.A.; Hu, J.J.; Zabinski, J.S.

    2002-01-01

    Nanocomposite tribological coatings were designed to respond to changing environmental conditions by self-adjustment of their surface properties to maintain good tribological performance in any environment. These smart coatings have been dubbed 'chameleon' because, analogous to a chameleon changing its skin color to avoid predators, the coating changes its 'skin' chemistry and structure to avoid wear. The concept was originally developed using WC, diamondlike carbon, and WS 2 material combination for adaptation to a humid/dry environment cycling. In order to address temperature variation, nanocomposite coatings made of yttria-stabilized zirconia (YSZ) in a gold matrix were developed with encapsulated nanosized reservoirs of MoS 2 and diamondlike carbon (DLC). Coatings were produced using a combination of laser ablation and magnetron sputtering. They were characterized by x-ray photoelectron spectroscopy, x-ray diffraction, transmission electron microscopy, x-ray energy dispersive spectroscopy, and micro-Raman spectroscopy. Results were correlated with mechanical and tribological characterization. Coating hardness was evaluated using nanoindentation, while coating adhesion and toughness were estimated using scratch and Vickers indentation tests. Friction and wear endurance measurements of YSZ/Au/MoS 2 /DLC coatings against steel and Si 3 N 4 balls were performed at room temperature in controlled humidity air, dry nitrogen, and vacuum environments, as well as at 500 deg. C in air. Depending on the environment, coating friction surface changed its chemistry and structure between (i) graphitic carbon for sliding in humid air [coating friction coefficients (c.o.f. 0.10-0.15)], (ii) hexagonal MoS 2 for sliding in dry N 2 and vacuum (c.o.f. 0.02-0.05), and (iii) metallic Au for sliding in air at 500 deg. C (c.o.f. 0.10-0.20). The unique coating skin adaptation realized with YSZ/Au/MoS 2 /DLC and WC/DLC/WS composites proves a universal applicability of the chameleon design

  11. SAPO-34 coated adsorbent heat exchanger for adsorption chillers

    International Nuclear Information System (INIS)

    Freni, Angelo; Bonaccorsi, Lucio; Calabrese, Luigi; Caprì, Angela; Frazzica, Andrea; Sapienza, Alessio

    2015-01-01

    In this work, adsorbent coatings on aluminum surfaces were prepared by dip-coating method starting from a water suspension of SAPO-34 zeolite and a silane-based binder. Silane-zeolite coatings morphology and surface coverage grade were evaluated by scanning electron microscopy. Adhesive and mechanical properties were evaluated by peel, pull-off, impact and micro-hardness tests, confirming the good interaction between metal substrate, binder and zeolite. Adsorption equilibrium and kinetics of water vapour adsorption on the adsorbent coating were studied in the range T = 30–150 °C and pH 2 O = 11 mbar using a CAHN 2000 thermo-balance. It was found that, in the investigated conditions, the organic binder doesn't affect the water adsorption capacity and adsorption kinetics of the original SAPO-34 zeolite. Subsequently, the zeolite coating was applied on a finned flat-tubes aluminum heat exchanger realizing a full-scale AdHEx with an uniform adsorbent coating 0.1 mm thick and a metal/adsorbent mass ratio = 6. The cooling capacity of the realized coated AdHEx was measured by a lab-scale adsorption chiller under realistic operating conditions for air conditioning applications. The coated AdHEx produced up to 675 W/kg ads specific cooling power with a cycle time of 5 min. Adsorption stability of the coated adsorber subjected to 600 sorption cycles was successfully verified. - Highlights: • Adsorbent coatings on aluminum surfaces were prepared by dip-coating method. • Silane-zeolite coatings morphology, and mechanical properties were studied. • The zeolite coating was applied on a finned flat-tubes aluminum heat exchanger. • The coated AdHEx was tested in a lab scale adsorption chiller

  12. Low Temperature Powder Coating

    Science.gov (United States)

    2011-02-09

    of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) • Legacy primers contain hexavalent chrome • Conventional powder coatings...coatings both in laboratory and field service evaluations • LTCPC allows environmental cost reductions through VOC/HAP elimination and hexavalent ... chrome reduction. • The LTCPC process greatly shortens the coating operation (LTCPC cures much more rapidly then conventional wet coatings) resulting in

  13. Development and evaluation of two PVD-coated β-titanium orthodontic archwires for fluoride-induced corrosion protection.

    Science.gov (United States)

    Krishnan, Vinod; Krishnan, Anand; Remya, R; Ravikumar, K K; Nair, S Asha; Shibli, S M A; Varma, H K; Sukumaran, K; Kumar, K Jyothindra

    2011-04-01

    The present research was aimed at developing surface coatings on β titanium orthodontic archwires capable of protection against fluoride-induced corrosion. Cathodic arc physical vapor deposition PVD (CA-PVD) and magnetron sputtering were utilized to deposit thin films of titanium aluminium nitride (TiAlN) and tungsten carbide/carbon (WC/C) coatings on β titanium orthodontic archwires. Uncoated and coated specimens were immersed in a high fluoride ion concentration mouth rinse, following a specially designed cycle simulating daily use. All specimens thus obtained were subjected to critical evaluation of parameters such as electrochemical corrosion behaviour, surface analysis, mechanical testing, microstructure, element release, and toxicology. The results confirm previous research that β titanium archwires undergo a degradation process when in contact with fluoride mouth rinses. The study confirmed the superior nature of the TiAlN coating, evident as many fewer changes in properties after fluoride treatment when compared with the WC/C coating. Thus, coating with TiAlN is recommended in order to reduce the corrosive effects of fluorides on β titanium orthodontic archwires. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  14. Development of radiation curable surface coating based on soybean oil. part II: Evaluation of the prepared acrylated resin as surface coatings by using EB or UV sources for radiation curing applications

    International Nuclear Information System (INIS)

    Ibrahim, M.S.; Said, H.M.; Moussa, I.M.

    2005-01-01

    In recent years, there has been a growing trend in using vegetable oils as raw materials in acylation production that can be cured by UV/EB systems. The acrylated resin formulates by using individually different functional acrylate monomers were prepared and cured by EB or UV sources. The characterization properties of the cured films were investigated in terms of pendulum hardness, bending, impact, gloss, adhesion and chemical tests. Other formulations were prepared by mixing a constant ratio of different functional acrylate monomers and exposed to UV or EB irradiation. The results showed that the hardness of cured films were increased by increasing the functionality of monomers with excellent adhesion for all formulations but at expense of other properties involving bending and impact tests. Therefore, it can be deduce that the hardness of the curing surface coating by using EB was found to be nearly twice the hardness of the curing surface coating by using UV irradiation. Also, the best formulations which have given good chemical and mechanical properties are (mono-di) functional acrylate monomer resin under EB and (mono-tri) functional acrylate monomer resin under UV irradiation

  15. Evaluating the effects of hydroxyapatite coating on the corrosion behavior of severely deformed 316Ti SS for surgical implants

    International Nuclear Information System (INIS)

    Mhaede, Mansour; Ahmed, Aymen; Wollmann, Manfred; Wagner, Lothar

    2015-01-01

    The present work investigates the effects of severe plastic deformation by cold rolling on the microstructure, the mechanical properties and the corrosion behavior of austenitic stainless steel (SS) 316Ti. Hydroxyapatite coating (HA) was applied on the deformed material to improve their corrosion resistance. The martensitic transformation due to cold rolling was recorded by X-ray diffraction spectra. The effects of cold rolling on the corrosion behavior were studied using potentiodynamic polarization. The electrochemical tests were carried out in Ringer's solution at 37 ± 1 °C. Cold rolling markedly enhanced the mechanical properties while the electrochemical tests referred to a lower corrosion resistance of the deformed material. The best combination of both high strength and good corrosion resistance was achieved after applying hydroxyapatite coating. - Highlights: • Cold rolling markedly increases the hardness of SS 316Ti from 125 to 460 HV10. • Higher deformation degrees lead to lower corrosion resistance. • Application of HA-coating leads to significant improvement of the corrosion resistance

  16. Microstructure and cytotoxicity evaluation of duplex-treated silver-containing antibacterial TiO{sub 2} coatings

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiangyu; Wu, Haibo; Geng, Zhenhua; Huang, Xiaobo; Hang, Ruiqiang; Ma, Yong; Yao, Xiaohong; Tang, Bin, E-mail: tangbin6405@sina.com

    2014-12-01

    Implant-related infection is one of the most common and serious complications associated with biomedical implantation. To prevent bacterial adhesion, a series of porous TiO{sub 2} coatings with different concentrations of silver (designated as M0, M1, M2 and M3) were prepared on pure titanium substrates by a duplex-treatment technique combining magnetron sputtering with micro-arc oxidation. All coatings are porous with pore size less than 5 μm and the concentrations of silver in the M0, M1, M2 and M3 are 0, 0.95, 1.36 and 1.93 wt.%, respectively. Silver is found to be distributed throughout the thickness of the coatings by scanning electron microscopy. The release of silver from the TiO{sub 2} coatings was confirmed by an inductively-coupled plasma mass spectroscopy. The antibacterial effects of these coatings were tested against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli), and the cytotoxicity was evaluated using the mouse pre-osteoblast cells. The results indicate that the antibacterial activities of TiO{sub 2} coatings are greatly improved due to the incorporation of silver. No cytotoxic effect is found for the M1 surfaces from the observation of pre-osteoblast cell by MTT assay and fluorescence microscopy. Although the M2 and M3 coatings appeared to be toxic for pre-osteoblast cells after 1 day in culture, the cell viability on M2 and M3 surfaces was greatly raised after culturing for 2 days. Our results suggested that the TiO{sub 2} coatings incorporated with an optimum amount of silver can possess excellent antibacterial activities without cytotoxic effect, which has promising applications in biomedical devices. - Highlights: • Porous TiO{sub 2} coatings with various concentration of Ag on titanium were prepared. • Ag element was distributed throughout the thickness of the coatings. • The antibacterial activities were greatly improved due to the incorporation of Ag. • The release amounts of Ag were

  17. Microstructure and cytotoxicity evaluation of duplex-treated silver-containing antibacterial TiO2 coatings

    International Nuclear Information System (INIS)

    Zhang, Xiangyu; Wu, Haibo; Geng, Zhenhua; Huang, Xiaobo; Hang, Ruiqiang; Ma, Yong; Yao, Xiaohong; Tang, Bin

    2014-01-01

    Implant-related infection is one of the most common and serious complications associated with biomedical implantation. To prevent bacterial adhesion, a series of porous TiO 2 coatings with different concentrations of silver (designated as M0, M1, M2 and M3) were prepared on pure titanium substrates by a duplex-treatment technique combining magnetron sputtering with micro-arc oxidation. All coatings are porous with pore size less than 5 μm and the concentrations of silver in the M0, M1, M2 and M3 are 0, 0.95, 1.36 and 1.93 wt.%, respectively. Silver is found to be distributed throughout the thickness of the coatings by scanning electron microscopy. The release of silver from the TiO 2 coatings was confirmed by an inductively-coupled plasma mass spectroscopy. The antibacterial effects of these coatings were tested against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli), and the cytotoxicity was evaluated using the mouse pre-osteoblast cells. The results indicate that the antibacterial activities of TiO 2 coatings are greatly improved due to the incorporation of silver. No cytotoxic effect is found for the M1 surfaces from the observation of pre-osteoblast cell by MTT assay and fluorescence microscopy. Although the M2 and M3 coatings appeared to be toxic for pre-osteoblast cells after 1 day in culture, the cell viability on M2 and M3 surfaces was greatly raised after culturing for 2 days. Our results suggested that the TiO 2 coatings incorporated with an optimum amount of silver can possess excellent antibacterial activities without cytotoxic effect, which has promising applications in biomedical devices. - Highlights: • Porous TiO 2 coatings with various concentration of Ag on titanium were prepared. • Ag element was distributed throughout the thickness of the coatings. • The antibacterial activities were greatly improved due to the incorporation of Ag. • The release amounts of Ag were initially high and gradually

  18. Evaluation of Iron and Manganese-Coated Pumice Application for the Removal of as(v from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Leila Babaie Far

    2012-12-01

    Full Text Available Arsenic contamination of water has been recognized as a serious environmental issue and there are reports on its epidemiological problems to human health. The objective of this study was to evaluate the performances of iron-coated pumice and manganese-coated pumice as the adsorbents for removing arsenate from aqueous solutions. The effect of various parameters such as adsorbent dose, contact time, pH and initial concentration on removal efficiency of arsenate were evaluated in batch mode. The data obtained from the kinetic studies were analyzed using kinetic models of pseudo-first-order and pseudo-second-order. In addition, two isotherm models of Freundlich and Langmuir were used to fit the experimental data. The results showed that the optimum dosage of iron-coated pumice and manganese-coated pumice for arsenate removal were 40 and 80 g/L whereas the adsorption process reached equilibrium after 80 and 100 min, respectively. The maximum removal efficiency of arsenate using the two adsorbents were both recorded in pH=3 as the removal efficiency gradually declinedfollowing every increase in pH values of the solution. Iron-coated pumice also showed to have high removal efficiency when the initial concentration of arsenate was high while the low concentration of arsenate was efficiently removed by manganese-coated pumice. Moreover, it was depicted that the adsorption kinetics by bothadsorbents followed pseudo-second order equation and the uptake data of arsenate were well fitted with Langmuir isotherm model. Therefore, it could be concluded that iron and manganese-coated pumice could beconsidered as suitable adsorbents for arsenate removal from aqueous solutions.

  19. Standard hardness conversion tables for metals relationship among brinell hardness, vickers hardness, rockwell hardness, superficial hardness, knoop hardness, and scleroscope hardness

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 Conversion Table 1 presents data in the Rockwell C hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.2 Conversion Table 2 presents data in the Rockwell B hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.3 Conversion Table 3 presents data on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, and Knoop hardness of nickel and high-nickel alloys (nickel content o...

  20. Investigation on the corrosion behavior of physical vapor deposition coated high speed steel

    Directory of Open Access Journals (Sweden)

    R Ravi Raja Malarvannan

    2015-08-01

    Full Text Available This work emphasizes on the influence of the TiN and AlCrN coatings fabricated on high speed steel form tool using physical vapor deposition technique. The surface microstructure of the coatings was studied using scanning electron microscope. Hardness and corrosion studies were also performed using Vickers hardness test and salt spray testing, respectively. The salt spray test results suggested that the bilayer coated (TiN- bottom layer and AlCrN- top layer substrate has undergone less amount of corrosion, and this is attributed to the dense microstructure. In addition to the above, the influence of the above coatings on the machining performance of the high speed steel was also evaluated and compared with that of the uncoated material and the results suggested that the bilayered coating has undergone very low weight loss when compared with that of the uncoated substrate depicting enhanced wear resistance.

  1. Processing-structure-property relationships in electron beam physical vapor deposited yttria stabilized zirconia coatings

    International Nuclear Information System (INIS)

    Rao, D. Srinivasa; Valleti, Krishna; Joshi, S. V.; Janardhan, G. Ranga

    2011-01-01

    The physical and mechanical properties of yttria stabilized zirconia (YSZ) coatings deposited by the electron beam physical vapor deposition technique have been investigated by varying the key process variables such as vapor incidence angle and sample rotation speed. The tetragonal zirconia coatings formed under varying process conditions employed were found to have widely different surface and cross-sectional morphologies. The porosity, phase composition, planar orientation, hardness, adhesion, and surface residual stresses in the coated specimens were comprehensively evaluated to develop a correlation with the process variables. Under transverse scratch test conditions, the YSZ coatings exhibited two different crack formation modes, depending on the magnitude of residual stress. The influence of processing conditions on the coating deposition rate, column orientation angle, and adhesion strength has been established. Key relationships between porosity, hardness, and adhesion are also presented.

  2. Evaluation of UV-permeability and photo-oxidisability of organic ultraviolet radiation-absorbing coatings

    Energy Technology Data Exchange (ETDEWEB)

    Li, Neng; Chen, Yuhe, E-mail: yuhec@sina.com; Bao, Yongjie; Zhang, Zeqian; Wu, Zaixing; Chen, Zhangmin

    2015-03-30

    Highlights: • We investigate organic UV radiation-absorbing coatings for use on bamboo surfaces. • The size of glass exactly inserted into sample cell of UV-Vis spectrophotometer. • A model was made to predict UV absorption of coatings. • We examine carbonyl groups change of coatings after ageing. • Two formulations which could effectively protect coating were obtained. - Abstract: Enhancing the durability of the coatings used on bamboo products is essential for increasing their use in outdoor environments. In this study, we investigated organic UV radiation-absorbing coatings for use on bamboo surfaces. The degree of resistance of the coatings, which contained 2-(2-hydroxy-3-tert-butyl-5-methyl-phenyl)-5-chlorinated benzotriazole (BTZ-1), to UV radiation degradation was determined through spectroscopic analysis. The critical BTZ-1 loading amount was determined by analysing the spectroscopic data. Fourier transform infrared spectroscopy was used to elucidate the relationship between the degree of photooxidation of the coatings and their BTZ-1 concentration. The experimental results showed that the coatings provided a high degree of shielding from UV radiation. The critical loading amount was determined to be 1.82 ± 0.05 g BTZ-1/m{sup 2}. The coatings formed using the formulations that contained 3 and 5 wt% BTZ-1 exhibited the lowest degree of photooxidation after exposure to UV radiation.

  3. Umbelliprenin-coated Fe3O4 magnetite nanoparticles: Antiproliferation evaluation on human Fibrosarcoma cell line (HT-1080)

    International Nuclear Information System (INIS)

    Khorramizadeh, M.R.; Esmail-Nazari, Z.; Zarei-Ghaane, Z.; Shakibaie, M.; Mollazadeh-Moghaddam, K.; Iranshahi, M.; Shahverdi, A.R.

    2010-01-01

    The potential applications of Fe 3 O 4 magnetite nanoparticles (MNPs) in nanomedicine as drug delivery systems are well known. In this study we prepared umbelliprenin-coated Fe 3 O 4 MNPs and evaluated the antiproliferative effect of combination in vitro. After synthesis of Fe 3 O 4 MNPs, particles were characterized by transmission electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction spectroscopy techniques. The natural candidate compound - umbelliprenin- was isolated and identified and umbelliprenin-coated Fe 3 O 4 MNPs were prepared, using precipitation method. The surface chemistry of umbelliprenin-coated Fe 3 O 4 MNPs as well as their thermal decomposition characteristics was examined using Fourier transform infrared spectroscopy and Thermogravimetric Analyzer equipment, respectively. HT-1080 cells were cultured until the logarithmic phase of growth, and MTT assay was successfully carried out to evaluate the possible cytotoxic effects of umbelliprenin-coated Fe 3 O 4 MNPs in viable cells in vitro. The results demonstrated that umbelliprenin has moderate antiproliferative effects with IC 50 value of 50 μg/mL. However, the combination of umbelliprenin and Fe 3 O 4 MNPs showed the IC 50 value of 9 μg/mL. In other words, cell proliferation decreased to the remarkably-low proportion of 45% after treating cells with umbelliprenin-coated Fe 3 O 4 MNPs. This suggests that with the aid of nanoparticles as carriers, natural products may have even broader range of medical applications in future.

  4. Development of improved lacv-30 propeller blade coatings for protection against sand and rain erosion and marine environment corrosion. Final report 4 Jan 1982-4 Mar 1983

    Energy Technology Data Exchange (ETDEWEB)

    Malone, G.A.

    1983-05-10

    An investigation was conducted of candidate systems offering potential erosion and corrosion protection when applied as coatings to Aluminum 7075 alloy propeller blades used to propel air cushioned vehicles operating in severe environments. This work focused on (1) special hard anodized and (2) hard nickel electroplated coatings as candidate protective systems with sand/rain erosion testing to evaluate their merits. Attributes of the coating systems developed and studied included: For (1) Ways and means to produce and control deposit hardness for optimum erosion resistance, methods of bonding to blades for high integrity adhesion, and inclusion of sacrificial corrosion protection electroplates in the coating systems (zinc and zinc-nickel alloy). For (2) Incorporation of dry film lubricant systems on sealed hardcoats of various anodic coating thicknesses to enhance erosion performance. Study results indicated that anodized coatings did not provide suitable erosion protection to Aluminum 7075 in sand/rain environments, even with dry film lubricant supplemental films. Electroplated hard nickel coatings, Vickers hardnesses in the range of 380 to 440, appeared better for combined sand/rain erosion resistance based on comparisons with prior work. Dilute phosphoric anodizing the aluminum substrates led to excellent bonds and improved corrosion resistance when subsequently plated with ductile nickel from a low pH bath, followed by hard nickel electroplate.

  5. Silver-doped nanocomposite carbon coatings (Ag-DLC) for biomedical applications – Physiochemical and biological evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Bociaga, Dorota, E-mail: dorota.bociaga1@gmail.com [Division of Biomedical Engineering and Functional Materials, Lodz University of Technology, Institute of Materials Science and Engineering, 1/15 Stefanowskiego St., 90-924 Lodz (Poland); Komorowski, Piotr [Division of Biophysics, Lodz University of Technology, Institute of Materials Science and Engineering, 1/15 Stefanowskiego St., 90-924 Lodz (Poland); BioNanoPark Laboratories of Lodz Regional Park of Science and Technology, Lodz (Poland); Batory, Damian [Division of Biomedical Engineering and Functional Materials, Lodz University of Technology, Institute of Materials Science and Engineering, 1/15 Stefanowskiego St., 90-924 Lodz (Poland); Szymanski, Witold [Division of Biophysics, Lodz University of Technology, Institute of Materials Science and Engineering, 1/15 Stefanowskiego St., 90-924 Lodz (Poland); Olejnik, Anna; Jastrzebski, Krzysztof [Division of Biomedical Engineering and Functional Materials, Lodz University of Technology, Institute of Materials Science and Engineering, 1/15 Stefanowskiego St., 90-924 Lodz (Poland); Jakubowski, Witold [Division of Biophysics, Lodz University of Technology, Institute of Materials Science and Engineering, 1/15 Stefanowskiego St., 90-924 Lodz (Poland)

    2015-11-15

    Graphical abstract: - Highlights: • The DLC coatings with interlayer improving adhesion were manufactured using the author's method in dual RF/MS PCVD system. • The Ag ions were incorporated into DLC matrix using ion beam implantation method. • The morphology, chemical structure and composition of coatings were examined. • Viability, cytotoxicity of human cells and the formation of bacterial biofilm on the samples surface were evaluated. • <5% of Ag in DLC coating is efficient to make it bactericidal and biocompatible. - Abstract: The formation of bacteria biofilm on the surface of medical products is a major clinical issue nowadays. Highly adaptive ability of bacteria to colonize the surface of biomaterials causes a lot of infections. This study evaluates samples of the AISI 316 LVM with special nanocomposite silver-doped (by means of ion implantation) diamond-like carbon (DLC) coating prepared by hybrid RF/MS PACVD (radio frequency/magnetron sputtering plasma assisted chemical vapour deposition) deposition technique in order to improve the physicochemical and biological properties of biomaterials and add new features such as antibacterial properties. The aim of the following work was to evaluate antimicrobial efficacy and biocompatibility of gradient a-C:H/Ti + Ag coatings in relation to the physiochemical properties of the surface and chemical composition of coating. For this purpose, samples were tested in live/dead test using two cell strains: human endothelial cells (Ea.hy926) and osteoblasts-like cells (Saos-2). For testing bactericidal activity of the coatings, an exponential growth phase of Escherichia coli strain DH5α was used as a model microorganism. Surface condition and its physicochemical properties were investigated using SEM, AFM and XPS. Examined coatings showed a uniformity of silver ions distribution in the amorphous DLC matrix, good biocompatibility in contact with mammalian cells and an increased level of bactericidal

  6. Silver-doped nanocomposite carbon coatings (Ag-DLC) for biomedical applications – Physiochemical and biological evaluation

    International Nuclear Information System (INIS)

    Bociaga, Dorota; Komorowski, Piotr; Batory, Damian; Szymanski, Witold; Olejnik, Anna; Jastrzebski, Krzysztof; Jakubowski, Witold

    2015-01-01

    Graphical abstract: - Highlights: • The DLC coatings with interlayer improving adhesion were manufactured using the author's method in dual RF/MS PCVD system. • The Ag ions were incorporated into DLC matrix using ion beam implantation method. • The morphology, chemical structure and composition of coatings were examined. • Viability, cytotoxicity of human cells and the formation of bacterial biofilm on the samples surface were evaluated. • <5% of Ag in DLC coating is efficient to make it bactericidal and biocompatible. - Abstract: The formation of bacteria biofilm on the surface of medical products is a major clinical issue nowadays. Highly adaptive ability of bacteria to colonize the surface of biomaterials causes a lot of infections. This study evaluates samples of the AISI 316 LVM with special nanocomposite silver-doped (by means of ion implantation) diamond-like carbon (DLC) coating prepared by hybrid RF/MS PACVD (radio frequency/magnetron sputtering plasma assisted chemical vapour deposition) deposition technique in order to improve the physicochemical and biological properties of biomaterials and add new features such as antibacterial properties. The aim of the following work was to evaluate antimicrobial efficacy and biocompatibility of gradient a-C:H/Ti + Ag coatings in relation to the physiochemical properties of the surface and chemical composition of coating. For this purpose, samples were tested in live/dead test using two cell strains: human endothelial cells (Ea.hy926) and osteoblasts-like cells (Saos-2). For testing bactericidal activity of the coatings, an exponential growth phase of Escherichia coli strain DH5α was used as a model microorganism. Surface condition and its physicochemical properties were investigated using SEM, AFM and XPS. Examined coatings showed a uniformity of silver ions distribution in the amorphous DLC matrix, good biocompatibility in contact with mammalian cells and an increased level of bactericidal

  7. Friction surfaced Stellite6 coatings

    International Nuclear Information System (INIS)

    Rao, K. Prasad; Damodaram, R.; Rafi, H. Khalid; Ram, G.D. Janaki; Reddy, G. Madhusudhan; Nagalakshmi, R.

    2012-01-01

    Solid state Stellite6 coatings were deposited on steel substrate by friction surfacing and compared with Stellite6 cast rod and coatings deposited by gas tungsten arc and plasma transferred arc welding processes. Friction surfaced coatings exhibited finer and uniformly distributed carbides and were characterized by the absence of solidification structure and compositional homogeneity compared to cast rod, gas tungsten arc and plasma transferred coatings. Friction surfaced coating showed relatively higher hardness. X-ray diffraction of samples showed only face centered cubic Co peaks while cold worked coating showed hexagonally close packed Co also. - Highlights: ► Stellite6 used as coating material for friction surfacing. ► Friction surfaced (FS) coatings compared with casting, GTA and PTA processes. ► Finer and uniformly distributed carbides in friction surfaced coatings. ► Absence of melting results compositional homogeneity in FS Stellite6 coatings.

  8. Theoretical modeling developed to evaluate the hardness and reduced modulus for the C/a-Si composite film using nanoindentation tests

    International Nuclear Information System (INIS)

    Han, C.-F.; Lin, J.-F.; Chung, C.-K.; Wu, B.-H.

    2008-01-01

    A general mechanical model, which is composed of the mechanical models employed to describe the contact behaviors and deformations arising in all layers (including the substrate), is successfully developed in the present study for multilayer specimens in order to evaluate the contact projected area by a theoretical model, and thus the hardness and reduced modulus, using nanoindentation tests. The governing differential equations for the depth solutions of the indenter tip formed at all layers of the specimen under their contact load are developed individually. The influence of the material properties of the substrate on a multilayer specimen's hardness and reduced modulus at various indentation depths can thus be evaluated. Transition and pop-in occurred at depths near, but still before, the C (top layer)/a-Si (buffer layer) interface and the a-Si/Si (substrate) interface, respectively. Using the present analysis, the depths corresponding to the transition and pop-in behaviors can be predicted effectively

  9. Experimental Evaluation of Polyester and Epoxy–Polyester Powder Coatings in Aggressive Media

    OpenAIRE

    Ivan Stojanović; Vinko Šimunović; Vesna Alar; Frankica Kapor

    2018-01-01

    Protective coatings are the most widely used corrosion protection method for construction materials in different environmental conditions. They isolate metals from aggressive media, making the structure more durable. Today, alongside good anti-corrosive properties, coatings need to be safe for the environment and harmless to those who apply them. The high volatile organic compound (VOC) content in conventional solvent-borne coatings presents a huge ecological problem. A solution for indispens...

  10. Evaluation of liposomes coated with a pH responsive polymer

    OpenAIRE

    Barea, M.J.; Jenkins, M.J.; Gaber, M.H.; Bridson, R.H.

    2010-01-01

    Liposomes have been coated with the pH responsive polymer, Eudragit S100, and the formulation's potential for lower gastrointestinal (GI) targeting following oral administration assessed. Cationic liposomes were coated with the anionic polymer through simple mixing. The evolution of a polymer coat was studied using zeta potential measurements and laser diffraction size analysis. Further evidence of an association between polymer and liposome was obtained using light and cryo scanning electron...

  11. Fabrication and evaluation of atmospheric plasma spraying WC-Co-Cu-MoS2 composite coatings

    International Nuclear Information System (INIS)

    Yuan Jianhui; Zhu Yingchun; Zheng Xuebing; Ji Heng; Yang Tao

    2011-01-01

    Research highlights: → Protective WC-Co-based coatings containing solid lubricant Cu and MoS 2 used in wear applications were investigated in this study. → It was found that the MoS 2 composition in the feed powder was kept in WC-Co-Cu-MoS 2 coatings, and the decomposition and decarburization of WC in APS process were improved. → Combining the wear resistance of WC with the lubricating properties of Cu and MoS 2 has an extremely beneficial effect on improving the tribological performance of the resulting coating. - Abstract: Protective WC-Co-based coatings containing solid lubricant Cu and MoS 2 used in wear applications were investigated in this study. These coatings were deposited on mild steel substrates by atmospheric plasma spraying (APS). The feedstock powders were prepared by mechanically mixing the solid lubricant powders and WC-Co powder, followed by sintering and crushing the mixtures to avoid different particle flighting trajectories at plasma. The tribological properties of the coatings against stainless steel balls were examined by ball-on-disk (BOD) tribometer under normal atmospheric condition. The microstructure of the coatings was studied by optical microscope, scanning electron microscope and X-ray diffraction. It was found that the MoS 2 composition in the feed powder was kept in WC-Co-Cu-MoS 2 coatings, and the decomposition and decarburization of WC in APS process were improved, which were attributed to the protection of Cu around them. The friction and wear behaviors of all the WC-Co-Cu-MoS 2 coatings were superior to that of WC-Co coating. Such behavior was associated to different wear mechanisms operating for WC-Co coating and the WC-Co-Cu-MoS 2 coatings.

  12. Evaluation of Moisture-Cure Urethane Coatings for Compliance with Industry Specifications

    Science.gov (United States)

    2011-12-01

    polyurethane coating with a thermoset binder and micaceous iron oxide pigment reinforcement. Since SSPC paint specifications are designed for zinc ...Outside Coating System No.2 (minimum AWWA OFT 7.5 mils) 1 ct. Corothane I GalvaPac Zinc Primer@ 3.0 mils dft 1 ct. Corothane Iron ox B@ 3.0 mils dft...Substrates Over properly prepared: Ferrous Metal Galvanized Metal Aluminium/Non-Ferrous Metal Ductile Iron Previously Existing Coatings

  13. MULTILAYER COATINGS Ti/TiN, Cr/CrN AND W/WN DEPOSITED BY MAGNETRON SPUTTERING FOR IMPROVEMENT OF ADHESION TO BASE MATERIALS

    Directory of Open Access Journals (Sweden)

    Jakub Horník

    2015-12-01

    Full Text Available The paper deals with evaluation of single and multilayer layer PVD coatings based on Cr and Ti widely used in tool application. Additionally, W and WN based coating which are not so widespread were designed and deposited as functionally graded material. The coatings properties were evaluated from the point of view of hardness and adhesion. The hardness measuring was carried out using nanoindentation method. The scratch test was performed to test adhesion. Moreover, the presence of metallic interlayer in functionally graded materials further increases the coating adhesion by gradually approaching its composition to the substrate. Coatings consisting of W and WN have showed very good adhesion. With regard to the results of the scratch test, the multilayer coatings of CrN, TiN and WN have increased adhesion and can be assumed to have their protective function improved. Results will be appliedin development of functionally graded layers for functionally graded materials.

  14. Microstructure and tribological property of nanocrystalline Co–W alloy coating produced by dual-pulse electrodeposition

    International Nuclear Information System (INIS)

    Su Fenghua; Huang Ping

    2012-01-01

    Highlights: ► The nanocrystalline Co–W alloy coating were produced by dual-pulse electrodeposition from aqueous bath with cobalt sulfate and sodium tungstate. ► The correlation between the electrodeposition condition, the microstructure and alloy composition, and the hardness and tribological properties of electrodeposited Co–W alloy coatings were established. ► By careful control of the electrodeposition condition and the bath composition, the Co–W alloy coating excellent performance of microhardness and tribological properties, can exhibit excellent performances of microhardness and tribological properties. - Abstract: The nanocrystalline Co–W alloy coatings were produced by dual-pulse electrodeposition from aqueous bath with cobalt sulfate and sodium tungstate (Na 2 WO 4 ). Influence of the current density and Na 2 WO 4 concentration in bath on the microstructure, morphology and hardness of the Co–W alloy coatings were investigated using an X-ray diffraction, a scanning electronic microscope and a Vickers hardness tester, respectively. In addition, the friction and wear properties of the Co–W alloy coating electrodeposited under different condition were evaluated with a ball-on-disk UMT-3MT tribometer. The correlation between the electrodeposition condition, the microstructure and alloy composition, and the hardness and tribological properties of the deposited Co–W alloy coatings were discussed in detail. The results showed that the microhardness of the deposited Co–W alloy coating was significantly affected by its average grain size, W content and crystal orientation. Smaller grain size, higher W content and strong hcp (1 0 0) orientation favor the improvement of the hardness for Co–W alloy coatings. The deposited Co–W alloy coating could obtain the maximum microhardness over 1000 kgf mm −2 by careful control of the electrodeposition conditions. The tribological properties of the electrodeposited Co–W alloy coating were greatly

  15. Coatings and Tints of Spectacle Lenses

    Directory of Open Access Journals (Sweden)

    H. Zeki Büyükyıldız

    2012-10-01

    Full Text Available Spectacle lenses are made of mineral or organic (plastic materials. Various coatings and tints are applied to the spectacle lenses according to the characteristic of the lens material, and for the personal needs and cosmetic purpose. The coatings may be classified in seven groups: 1 Anti-reflection coatings, 2 Hard coatings, 3 Clean coat, 4 Mirror coatings, 5 Color tint coating (one of coloring processes, 6 Photochromic coating (one of photochromic processes, and 7 Anti-fog coatings. Anti-reflection coatings reduce unwanted reflections from the lens surfaces and increase light transmission. Hard coatings are applied for preventing the plastic lens surface from scratches and abrasion. Hard coatings are not required for the mineral lenses due to their hardness. Clean coat makes the lens surface smooth and hydrophobic. Thus, it prevents the adherence of dust, tarnish, and dirt particles on the lens surface. Mirror coatings are applied onto the sunglasses for cosmetic purpose. Color tinted and photochromic lenses are used for sun protection and absorption of the harmful UV radiations. Anti-fog coatings make the lens surface hydrophilic and prevent the coalescence of tiny water droplets on the lens surface that reduces light transmission. (Turk J Ophthalmol 2012; 42: 359-69

  16. Experimental initial partial polymerization method for Fuji II placement evaluated for microleakage with/without Fuji Coat.

    Science.gov (United States)

    Chen, J W; Fletcher, B; Roggenkamp, C L

    2013-01-01

    This laboratory study evaluated an experimental 1-second initial partial polymerization (IPP) technique using Fuji II LC vs the manufacturer's standard placement (control), both with and without Fuji Coat, relative to microleakage. Class V restorative preparations were placed on the buccal and lingual aspects of 30 permanent, caries-free and restoration-free, third molar teeth. Fuji II LC restorations were placed either following manufacturer-specified guidelines or IPP for 1 second prior to contouring and full light curing. Half of the restorations were placed using the IPP experimental technique and half of the teeth were finished using Fuji Coat LC. Following thermocycling, specimens were sectioned and dye penetration was measured. SPSS 16 was used for statistical analysis (pCoat LC results in further diminished microleakage.

  17. Evaluation of anti-scale property of CrN coatings at high temperature and high pressure

    International Nuclear Information System (INIS)

    Honda, Tomomi; Iwai, Yoshiro; Uno, Ryoji; Yoshinaga, Shigeki

    2007-01-01

    It is well known that oxide scale which adheres to the inner wall of the nozzle in nuclear power plant causes a serious problem. This study was carried out to obtain the knowledge about initiation and deposition behavior of oxide scale on the surface of SUS304 stainless steel and the evaluation of anti-scale property of chromium nitride (CrN) coatings at high temperature and high pressure. SUS304 stainless steel and CrN coating specimens were heated in water up to 200degC for more than 250 hours. Obtained results are summarized as follows. Initiation of the scale started from corrosive part of SUS304 stainless steel and the scale grows by deposition of magnetite particles. CrN coating can be applied to prevent the initiation and deposition of oxide scale. (author)

  18. Study of Different Sol-Gel Coatings to Enhance the Lifetime of PDMS Devices: Evaluation of Their Biocompatibility.

    Science.gov (United States)

    Aymerich, María; Gómez-Varela, Ana I; Álvarez, Ezequiel; Flores-Arias, María T

    2016-08-25

    A study of PDMS (polydimethylsiloxane) sol-gel-coated channels fabricated using soft lithography and a laser direct writing technique is presented. PDMS is a biocompatible material that presents a high versatility to reproduce several structures. It is widely employed in the fabrication of preclinical devices due to its advantages but it presents a rapid chemical deterioration to organic solvents. The use of sol-gel layers to cover the PDMS overcomes this problem since it provides the robustness of glass for the structures made with PDMS, decreasing its deterioration and changing the biocompatibility of the surface. In this work, PDMS channels are coated with three different kinds of sol-gel compositions (60MTES/40TEOS, 70MTES/30TISP and 80MTES/20TISP). The endothelial cell adhesion to the different coated devices is evaluated in order to determine the most suitable sol-gel preparation conditions to enhance cellular adhesion.

  19. Designing, preparing and evaluation of novel HA/Ti composite coating for endodontic dental implant

    Directory of Open Access Journals (Sweden)

    Fathi MH.

    2002-08-01

    Full Text Available Nowadays, application of implants as a new method for replacing extracted teeth have been improved. So, many researches have been performed for improving the characteristics of implants. The aim of this study was to design and produce a desired coating in order to obtaining two goals including; improvement of the corrosion behavior of metallic endodontic implant and the bone osseointegration simultaneously. Stainless steel 316L (SS, cobalt-chromium alloy (Vit and commercial pure titanium (cpTi were chosen as metallic substrates and hydroxyapatite coating (HAC were performed by plasma-spraying (PS process on three different substrates. A novel double layer Hydroxyapatite/Titanium (HA/Ti composite coating composed of a HA top layer and a Ti under layer was prepared using PS and physical vapor deposition (PVD process respectively on SS. Structural characterization techniques including XRD, SEM and EDX were utilized to investigate the microstructure, morpholgy and crystallinity of the coatings. Electrochemical potentiodynamic tests were performed in physiological solutions in order to determine and compare the corrosion behavior of the coated and uncoated specimens behavior as an indication of biocmpatibility. Results indicated that the cpTi possesses the highest and SS the lowest corrosion resistance (highest corrosion current density between uncoated substrates. This trend was independent to the type of physiological environment. The HA coating decreased the corrosion current density of HA coated metallic implants but did not change that trend. HAC acted as a mechanical barrier on the metallic substrate but could not prevent the interaction between metallic substrate and environment completely. The HA/Ti composite coating improved the corrosion behavior of SS. The corrosion current density of HA/Ti coated SS decreased and was exactly similar to single HA coated cpTi in physiological solutions. The results indicated that HA/Ti composite coated SS

  20. The evaluation of arterial stiffness of essential hypertension and white coat hypertension in children: a case-control study.

    Science.gov (United States)

    Tokgöz, Semiha Terlemez; Yılmaz, Dilek; Tokgöz, Yavuz; Çelik, Bülent; Bulut, Yasin

    2018-03-01

    The aim of this study was to determine and compare cardiovascular risks by assessing arterial stiffness in children with essential hypertension and white coat hypertension. Paediatric patients followed up with essential hypertension and white coat hypertension diagnoses and with no established end organ damage were involved in the study. Arterial stiffness in children included in the study was evaluated and compared by using the oscillometric device (Mobil-O-Graph) method. A total of 62 essential hypertension (34 male, 28 female), 38 white coat hypertension (21 male, 17 female), and 60 healthy controls (33 male, 27 female) were assessed in the present study. Pulse wave velocity of the essential hypertension, white coat hypertension, and control group was, respectively, as follows: 5.3±0.6 (m/s), 5.1±0.4 (m/s), 4.3±0.4 (m/s) (pcoat hypertension were found to be higher compared with the control group. This level was identified as correlated with the duration of hypertension in both patient groups (pcoat hypertension was impaired compared with healthy children. This finding has made us think that white coat hypertension is not an innocent clinical situation. This information should be taken into consideration in the follow-up and treatment approaches of the patients.

  1. A novel blister test to evaluate the interface strength between nickel coating and low carbon steel substrate

    International Nuclear Information System (INIS)

    Xiao, L.H.; Su, Xu Ping.; Wang, J.H.; Zhou, Y.C.

    2009-01-01

    A novel blister test theory model was developed based on the bending theory of beams for assessing the interface strength of the nickel coating/low carbon steel substrate material system. The strain energy of the debonded nickel coating was calculated analytically and by finite element analysis, respectively. The analytic solutions agree well with the FE calculation results. Some blister tests were carried out on the WII-5 Computer Controlled Material Mechanical Properties Testing Machine, using four nickel-coated specimens type-A, -B, -C and -D which were electrodeposited on low carbon steel substrate. Here, types A, B, C and D correspond to the nickel coating thickness of 5 μm, 10 μm, 15μm and 25μm, respectively. The interface strength, evaluated by this blister test method, is 196.86 J/m 2 and 269.40 J/m 2 for type-C and -D specimens, respectively. However the tests demonstrate that the type-A and -B specimens were cut through by the spindle and no delaminations between the coating and the substrate could be found

  2. Evaluation of organic coatings to reduce air leakage through cracks in the Pickering NGS 'A' reactor building 1

    International Nuclear Information System (INIS)

    Deans, J.J.; Sato, J.A.; Hampton, J.H.D.; Cullen, R.; Paterson, G.; Chan, P.; Rajagopalan, R.

    1994-01-01

    Pressure tests conducted in 1992 on the Pickering NGS 'A' Reactor Building 1 showed that the containment leakage rate of the building was close to the licensing limit. The leakage was found to be pressure dependent and was attributed to cracks in the concrete dome. A number of solutions were studied by a task group, and the application of an organic coating to the exterior surface of the dome was identified as the most viable solution under the constraints of schedule and cost. In addition to reducing the air leakage rate, the coating material must be flexible to bridge existing moving cracks, it must have excellent adhesion to the concrete substrate to sustain the design pressure of 41.4 kPa(g) during pressure tests, and it must be durable for an exterior application and service conditions. Five candidate organic coating materials were selected for laboratory testing. As a result of the testing, a single-component elastomeric polyurethane coating was selected to be used on the dome. This paper discusses the selection process, laboratory tests and results, and the application of the polyurethane coating system to the exterior concrete dome surface. However, the main emphasis of the paper is on the laboratory evaluation of the five candidate materials. (author). 2 refs., 3 tabs., 1 fig

  3. Alendronate Sodium as Enteric Coated Solid Lipid Nanoparticles; Preparation, Optimization, and In Vivo Evaluation to Enhance Its Oral Bioavailability.

    Directory of Open Access Journals (Sweden)

    Khaled Mohamed Hosny

    Full Text Available Treatment of osteoporosis with alendronate sodium has several challenges. The first challenge is the low bioavailability. The second main challenge is side effects, which include oesophageal ulceration. The aim of this research was to reformulate alendronate sodium as enteric coated solid lipid nanoparticles in order to enhance its bioavailability, and preventing the free alendronate sodium from coming into direct contact with the gastrointestinal mucosa, and thereby reducing the possibility of side effects. Enteric coated solid lipid nanoparticles were prepared according to the Box-Behnken design employing Design expert® software, and characterized for size, morphology, and entrapment efficiency. The optimized formula was coated with an Eudragit S100 and evaluated for drug release in acidic and basic media, stability studies and pharmacokinetic evaluations on rabbits. The results indicated that, using Derringer's desirability functional tool for optimization, the highest entrapment efficiency value of 74.3% and the smallest size value of 98 nm were predicted under optimum conditions with a desirability value of 0.917. The optimized nanoparticles released alendronate sodium only at an alkaline pH. The pharmacokinetic evaluation revealed that alendronate sodium bioavailability was enhanced by more than 7.4-fold in rabbits. In conclusion, enteric coated solid lipid nanoparticles is a promising formula for the delivery of alendronate sodium, eliminating its oesophageal side effects and enhancing its bioavailability.

  4. CONTEMPORARY PROBLEMS OF EVALUATION OF HYPERTENSION TREATMENT EFFICACY: MASKED HYPERTENSION AND WHITE COAT HYPERTENSION

    Directory of Open Access Journals (Sweden)

    V. M. Gorbunov

    2016-01-01

    Full Text Available The implementation of contemporary ambulatory methods of BP level evaluation in clinical practice improved diagnostics of arterial hypertension (HT, but at the same time faced with specific problems. White coat HT (WCHT and masked HT are characterized by inconsistency between ambulatory and clinical BP levels. Studying of these conditions in patients receiving antihypertensive therapy is important. The WCHT during treatment (target ambulatory BP levels and no control of clinical BP is observed in 10-20% of patients. The cardiovascular risk in these patients does not differ significantly from the risk in patients with controlled BP. Masked HT (target levels of clinical BP and no control of ambulatory BP is observed in 5,4-23% of patients. The cardiovascular risk in patients with masked HT is 2,5-3,0 times more than that in patients with controlled HT and comparable with risk in patients with ineffective antihypertensive therapy. Thus, clinical measurements can give inexact data about true BP level in one third of treated hypertensive patients. Therefore the evaluation of cardiovascular risk and correct usage of ambulatory BP measurement is important for choice of therapy tactics in patients with HT. 

  5. CONTEMPORARY PROBLEMS OF EVALUATION OF HYPERTENSION TREATMENT EFFICACY: MASKED HYPERTENSION AND WHITE COAT HYPERTENSION

    Directory of Open Access Journals (Sweden)

    V. M. Gorbunov

    2009-01-01

    Full Text Available The implementation of contemporary ambulatory methods of BP level evaluation in clinical practice improved diagnostics of arterial hypertension (HT, but at the same time faced with specific problems. White coat HT (WCHT and masked HT are characterized by inconsistency between ambulatory and clinical BP levels. Studying of these conditions in patients receiving antihypertensive therapy is important. The WCHT during treatment (target ambulatory BP levels and no control of clinical BP is observed in 10-20% of patients. The cardiovascular risk in these patients does not differ significantly from the risk in patients with controlled BP. Masked HT (target levels of clinical BP and no control of ambulatory BP is observed in 5,4-23% of patients. The cardiovascular risk in patients with masked HT is 2,5-3,0 times more than that in patients with controlled HT and comparable with risk in patients with ineffective antihypertensive therapy. Thus, clinical measurements can give inexact data about true BP level in one third of treated hypertensive patients. Therefore the evaluation of cardiovascular risk and correct usage of ambulatory BP measurement is important for choice of therapy tactics in patients with HT. 

  6. Development and evaluation of diltiazem hydrochloride controlled-release pellets by fluid bed coating process

    Directory of Open Access Journals (Sweden)

    Mikkilineni Bhanu Prasad

    2013-01-01

    Full Text Available The aim of the present study was to develop controlled-release pellets of diltiazem HCl with ethyl cellulose and hydroxylpropyl methylcellulose phthalate as the release rate retarding polymers by fluid bed coating technique. The prepared pellets were evaluated for drug content, particle size, subjected to Scanning Electron Microscopy (SEM and Differential Scanning Calori metry (DSC, and evaluated for in vitro release. Stability studies were carried out on the optimized formulations for a period of 3 months. The drug content was in the range of 97%-101%. The mean particle size of the drug-loaded pellets was in the range 700-785 μm. The drug release rate decreased as the concentration of ethyl cellulose increased in the pellet formulations. Among the prepared formulations, FDL10 and FDL11 showed 80% drug release in 16 h, matching with USP dissolution test 6 for diltiazem HCl extended-release capsules. SEM photographs confirmed that the prepared formulations were spherical in nature with a smooth surface. The compatibility between drug and polymers in the drug-loaded pellets was confirmed by DSC studies. Stability studies indicated that the pellets were stable.

  7. A Field Performance Evaluation Scheme for Microwave-Absorbing Material Coatings

    Directory of Open Access Journals (Sweden)

    Shaopeng Guan

    2017-03-01

    Full Text Available Performance evaluation is an important aspect in the study of microwave-absorbing material coatings. The reflectivity of the incident wave is usually taken as the performance indicator. There have been various methods to directly or indirectly measure the reflectivity, but existing methods are mostly cumbersome and require a strict testing environment. What is more, they cannot be applied to field measurement. In this paper, we propose a scheme to achieve field performance evaluation of microwave-absorbing materials, which adopts a small H-plane sectoral horn antenna as the testing probe and a small microwave reflectometer as the indicator. When the size of the H-plane sectoral horn antenna is specially designed, the field distribution at the antenna aperture can be approximated as a plane wave similar to the far field of the microwave emitted by a radar unit. Therefore, the reflectivity can be obtained by a near-field measurement. We conducted experiments on a kind of ferrite-based microwave-absorbing material at X band (8.2–12.4 GHz to validate the scheme. The experimental results show that the reflectivity is in agreement with the reference data measured by the conventional method as a whole.

  8. Evaluation of magnetostrictive composite coated fabric as a fragment barrier material

    International Nuclear Information System (INIS)

    Son, Kwon Joong; Fahrenthold, Eric P

    2012-01-01

    Over the last decade a surge in fragment barrier research has led to investigation of numerous materials and material augmentations in the attempt to improve the ballistic performance of systems designed to protect personnel, vehicles or infrastructure from impact and blast loads. One widely studied material augmentation approach is the use of coatings, often polymers, to enhance the performance of protection systems constructed from metal, concrete, composite and fabric materials. In recent research the authors have conducted the first experimental study of the ballistic performance of fabrics coated with a magnetically responsive polymer. Zero field impact experiments on coated fabric targets showed a 61% increase in impact energy dissipation, although the coated targets were not competitive with neat fabrics on a protection per unit mass basis. Under an applied field of 110 kA m −1 , the ballistic performance of the coated fabric was reduced. The reduction in performance may be attributed to a reduction in material damping and an increase in material modulus for the magnetostrictive component of the coating. Analysis of the coated fabric response to magnetic preloads suggests that coating tensile stresses and coating–fabric interface stresses induced by the applied field may also adversely affect ballistic performance. (paper)

  9. Evaluation of Osseous Integration of PVD-Silver-Coated Hip Prostheses in a Canine Model

    Directory of Open Access Journals (Sweden)

    Gregor Hauschild

    2015-01-01

    Full Text Available Infection associated with biomaterials used for orthopedic prostheses remains a serious complication in orthopedics, especially tumor surgery. Silver-coating of orthopedic (megaprostheses proved its efficiency in reducing infections but has been limited to surface areas exposed to soft tissues due to concerns of silver inhibiting osseous integration of cementless stems. To close this gap in the bactericidal capacity of silver-coated orthopedic prostheses extension of the silver-coating on surface areas intended for osseous integration seems to be inevitable. Our study reports about a PVD- (physical-vapor-deposition- silver-coated cementless stem in a canine model for the first time and showed osseous integration of a silver-coated titanium surface in vivo. Radiological, histological, and biomechanical analysis revealed a stable osseous integration of four of nine stems implanted. Silver trace elemental concentrations in serum did not exceed 1.82 parts per billion (ppb and can be considered as nontoxic. Changes in liver and kidney functions associated with the silver-coating could be excluded by blood chemistry analysis. This was in accordance with very limited metal displacement from coated surfaces observed by laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS 12 months after implantation. In conclusion our results represent a step towards complete bactericidal silver-coating of orthopedic prostheses.

  10. Evaluation of osseous integration of PVD-silver-coated hip prostheses in a canine model.

    Science.gov (United States)

    Hauschild, Gregor; Hardes, Jendrik; Gosheger, Georg; Stoeppeler, Sandra; Ahrens, Helmut; Blaske, Franziska; Wehe, Christoph; Karst, Uwe; Höll, Steffen

    2015-01-01

    Infection associated with biomaterials used for orthopedic prostheses remains a serious complication in orthopedics, especially tumor surgery. Silver-coating of orthopedic (mega)prostheses proved its efficiency in reducing infections but has been limited to surface areas exposed to soft tissues due to concerns of silver inhibiting osseous integration of cementless stems. To close this gap in the bactericidal capacity of silver-coated orthopedic prostheses extension of the silver-coating on surface areas intended for osseous integration seems to be inevitable. Our study reports about a PVD- (physical-vapor-deposition-) silver-coated cementless stem in a canine model for the first time and showed osseous integration of a silver-coated titanium surface in vivo. Radiological, histological, and biomechanical analysis revealed a stable osseous integration of four of nine stems implanted. Silver trace elemental concentrations in serum did not exceed 1.82 parts per billion (ppb) and can be considered as nontoxic. Changes in liver and kidney functions associated with the silver-coating could be excluded by blood chemistry analysis. This was in accordance with very limited metal displacement from coated surfaces observed by laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) 12 months after implantation. In conclusion our results represent a step towards complete bactericidal silver-coating of orthopedic prostheses.

  11. Influence of Plasma Transferred Arc Process Parameters on Structure and Mechanical Properties of Wear Resistive NiCrBSi-WC/Co Coatings

    Directory of Open Access Journals (Sweden)

    Eitvydas GRUZDYS

    2011-07-01

    Full Text Available Self-fluxing NiCrBSi and related coatings received considerable interest due to their good wear as well as corrosion resistance at moderate and elevated temperatures. Hard tungsten carbide (WC particles can be included in NiCrBSi for further increase of the coating hardness and abrasive wear resistance. Flame spray technique is widely used for fabrication of NiCrBSi films. However, in such a case, subsequent remelting of the deposited coatings by flame, arc discharge or high power laser beam is necessary. In present study NiCrBSi-WC/Co coatings were formed using plasma transferred arc process. By adjusting plasma parameters, such as current, plasma gas flow, shielding gas flow, a number of coatings were formed on steel substrates. Structure of the coatings was investigated using X-ray diffractometry. Microstructure of cross-sectioned coatings was examined using scanning electron microscopy. Hardness of the coating was evaluated by means of the Vickers hardness tests. Wear tests were also performed on specimens to determine resistance to abrasive wear. Acquired results allowed estimating the influence of the deposition process parameters on structure and mechanical properties of the coatings.http://dx.doi.org/10.5755/j01.ms.17.2.482

  12. Comparative Evaluation of Osseointegration of Dental Endodontic Implants with and without Plasma- Sprayed Hydroxy apatite Coating

    Directory of Open Access Journals (Sweden)

    Moosavi SB

    2001-05-01

    Full Text Available Bone osseointegration around dental implant can cause earlier stabilization and fixation of implant and reduce healing time. Hydroxyapatite coating can affect bone osseointegration and enhance its rates. The aim of this study was comparison of osseointegration between plasma sprayed hydroxyapatite coated and uncoated dental implants in cats. Four endodontic implants including, vitallium and two stainless steel with and without hydroxyapatite coating were prepared and placed in mandibular canines of 20 cats after completion of root canal treatment and osseous preparation. After a healing period of 4 months, investigation by scanning electron microscopy showed significant difference in ossointegration between coated and uncoated dental implants and average bone osseointegration of coated implants was more than uncoated implants.

  13. Evaluation of thermal control coatings for use on solar dynamic radiators in low earth orbit

    Science.gov (United States)

    Dever, Joyce A.; Rodriguez, Elvin; Slemp, Wayne S.; Stoyack, Joseph E.

    1991-01-01

    Thermal control coatings with high thermal emittance and low solar absorptance are needed for Space Station Freedom (SSF) solar dynamic power module radiator (SDR) surfaces for efficient heat rejection. Additionally, these coatings must be durable to low earth orbital (LEO) environmental effects of atomic oxygen, ultraviolet radiation and deep thermal cycles which occur as a result of start-up and shut-down of the solar dynamic power system. Eleven candidate coatings were characterized for their solar absorptance and emittance before and after exposure to ultraviolet (UV) radiation (200 to 400 nm), vacuum UV (VUV) radiation (100 to 200 nm) and atomic oxygen. Results indicated that the most durable and best performing coatings were white paint thermal control coatings Z-93, zinc oxide pigment in potassium silicate binder, and YB-71, zinc orthotitanate pigment in potassium silicate binder. Optical micrographs of these materials exposed to the individual environmental effects of atomic oxygen and vacuum thermal cycling showed that no surface cracking occurred.

  14. Nanoindentation study of WC-12Co hardmetals obtained from nanocrystalline powders: Evaluation of hardness and modulus on individual phases

    International Nuclear Information System (INIS)

    Bonache, V.; Rayon, E.; Salvador, M.D.; Busquets, D.

    2010-01-01

    With the development of finer hardmetals, the study of mechanical properties of the different constituents down the micrometric level is a question of concern for materials optimization. Nanoindentation has been developed in last years in order to cope with mechanical characterisation at the nanolevel, but difficulties on phase detection are an issue. In the present work, individual hardness and Young's modulus of the constituents of WC-12Co composite were obtained by the use of very shallow nanoindentations (30 nm depth), with the aid of in situ 3D imaging to identify these. By this method three different phases at the sub-micrometric level have been identified and characterised: namely cobalt matrix, tungsten carbide and η phase. The presence of the latter phase and its characterisation is of paramount importance in understanding the behaviour of hardmetals. Values of hardness from 8 (cobalt matrix) to 25 GPa (η phase) have been obtained. Also, for these phases Young's modulus varied from 250 to 400 GPa respectively. Furthermore, it is firstly reported these values for the WC prismatic planes {1 0 1 0} being in the range of 40-55 and 700-900 GPa respectively. These values decrease to a hardness in the range of 25-30 GPa and modulus in the range from 450 to 550 GPa for the WC basal plane {0 0 0 1}.

  15. SEM evaluation of the morphological changes in hard dental tissues prepared by Er: YAG laser and rotary instruments

    Directory of Open Access Journals (Sweden)

    Tomov Georgi

    2010-09-01

    Full Text Available Effective ablation of dental hard tissues by means of the erbium:yttrium-aluminum garnet (Er: YAG laser has been reported recently, and its application to caries removal and cavity preparation has been expected. However, few studies have investigated the morphological changes in hard dental tissues after Er: YAG laser caries treatment. In the present study the morphological changes in hard dental tissues after Er: YAG laser caries ablation in vitro was compared with that of conventional mechanical treatment. Thirty extracted human teeth with caries were used. Ten tooth was treated with the Er: YAG laser, and the other was treated with a conventional steel and diamond burs. Laser treatment was performed by means of a non-contact irradiation modes with cooling water spray, with a new Er: YAG laser (LiteTouch. Conventional bur treatment was conducted by means of a low-speed micromotor and air turbine with water cooling. Scanning electron microscope (SEM observations were performed for each treatment. The Er: YAG laser ablated carious dentin effectively with minimal thermal damage to the surrounding intact dentin, and removed infected and softened carious dentin to the same degree as the burtreatment. In addition, a lower degree of vibration was noted with the Er: YAG laser treatment. The SEM examination revealed characteristic micro-irregularities of the lased dentin and enamel surfaces with potential benefits for adhesive restorations. Our results show that the Er: YAG laser is promising as a new technical modality for caries treatment

  16. Evaluating the Relationships Between NTNU/SINTEF Drillability Indices with Index Properties and Petrographic Data of Hard Igneous Rocks

    Science.gov (United States)

    Aligholi, Saeed; Lashkaripour, Gholam Reza; Ghafoori, Mohammad; Azali, Sadegh Tarigh

    2017-11-01

    Thorough and realistic performance predictions are among the main requisites for estimating excavation costs and time of the tunneling projects. Also, NTNU/SINTEF rock drillability indices, including the Drilling Rate Index™ (DRI), Bit Wear Index™ (BWI), and Cutter Life Index™ (CLI), are among the most effective indices for determining rock drillability. In this study, brittleness value (S20), Sievers' J-Value (SJ), abrasion value (AV), and Abrasion Value Cutter Steel (AVS) tests are conducted to determine these indices for a wide range of Iranian hard igneous rocks. In addition, relationships between such drillability parameters with petrographic features and index properties of the tested rocks are investigated. The results from multiple regression analysis revealed that the multiple regression models prepared using petrographic features provide a better estimation of drillability compared to those prepared using index properties. Also, it was found that the semiautomatic petrography and multiple regression analyses provide a suitable complement to determine drillability properties of igneous rocks. Based on the results of this study, AV has higher correlations with studied mineralogical indices than AVS. The results imply that, in general, rock surface hardness of hard igneous rocks is very high, and the acidic igneous rocks have a lower strength and density and higher S20 than those of basic rocks. Moreover, DRI is higher, while BWI is lower in acidic igneous rocks, suggesting that drill and blast tunneling is more convenient in these rocks than basic rocks.

  17. Microstructural degradation mechanisms during creep in strength enhanced high Cr ferritic steels and their evaluation by hardness measurement

    International Nuclear Information System (INIS)

    Ghassemi Armaki, Hassan; Chen, Ruiping; Kano, Satoshi; Maruyama, Kouichi; Hasegawa, Yasushi; Igarashi, Masaaki

    2011-01-01

    Graphical abstract: Effect of static recovery on the acceleration of subgrain coarsening during creep plastic deformation. Display Omitted Highlights: → Short-term 'H' and long-term 'L' creep regions have different creep characteristics. → Strain-induced recovery of subgrains proceeds in the both creep regions 'H' and 'L'. → In region ''L', two additional degradation mechanisms accelerate creep failure. → Thermal coarsening of precipitates and subgrains appear during long-term creep ''L'. → In region 'L', strain-induced coarsening of precipitates accelerates creep failure. - Abstract: There are two creep regions with different creep characteristics: short-term creep region 'H', where precipitates and subgrains are thermally stable, and long-term creep region 'L', where thermal coarsening of precipitates and subgrains appear. In region 'H', the normalized subgrain size (λ-λ 0 )/(λ * -λ 0 ) has a linear relation with creep strain and its slope is 10ε -1 . But, region L is the time range in which the static recovery and the strain-induced recovery progress simultaneously. In this region, the static recovery accelerates the strain-induced recovery, and subgrain size is larger than that line which neglects the contribution of the static recovery. In region 'L', the Δλ/Δλ * -strain present a linear relation with a slope 35ε -1 . There is a linear relation between hardness and subgrain size. Hardness drop, H 0 - H, as a function of Larson-Miller parameter can be a good measure method for assessment of hardness drop and consequently degradation of microstructure. Hardness drop shows an identical slope in creep region 'H', whereas hardness drop due to thermal aging and creep in region 'L' show together a similar slope. In region 'H', degradation of microstructure is mainly due to recovery of subgrains controlled by creep plastic deformation, and precipitates do not have a major role. However, in creep region 'L', there are three degradation mechanisms

  18. Evaluation of silk biomaterials in combination with extracellular matrix coatings for bladder tissue engineering with primary and pluripotent cells.

    Science.gov (United States)

    Franck, Debra; Gil, Eun Seok; Adam, Rosalyn M; Kaplan, David L; Chung, Yeun Goo; Estrada, Carlos R; Mauney, Joshua R

    2013-01-01

    Silk-based biomaterials in combination with extracellular matrix (ECM) coatings were assessed as templates for cell-seeded bladder tissue engineering approaches. Two structurally diverse groups of silk scaffolds were produced by a gel spinning process and consisted of either smooth, compact multi-laminates (Group 1) or rough, porous lamellar-like sheets (Group 2). Scaffolds alone or coated with collagen types I or IV or fibronectin were assessed independently for their ability to support attachment, proliferation, and differentiation of primary cell lines including human bladder smooth muscle cells (SMC) and urothelial cells as well as pluripotent cell populations, such as murine embryonic stem cells (ESC) and induced pluripotent stem (iPS) cells. AlamarBlue evaluations revealed that fibronectin-coated Group 2 scaffolds promoted the highest degree of primary SMC and urothelial cell attachment in comparison to uncoated Group 2 controls and all Group 1 scaffold variants. Real time RT-PCR and immunohistochemical (IHC) analyses demonstrated that both fibronectin-coated silk groups were permissive for SMC contractile differentiation as determined by significant upregulation of α-actin and SM22α mRNA and protein expression levels following TGFβ1 stimulation. Prominent expression of epithelial differentiation markers, cytokeratins, was observed in urothelial cells cultured on both control and fibronectin-coated groups following IHC analysis. Evaluation of silk matrices for ESC and iPS cell attachment by alamarBlue showed that fibronectin-coated Group 2 scaffolds promoted the highest levels in comparison to all other scaffold formulations. In addition, real time RT-PCR and IHC analyses showed that fibronectin-coated Group 2 scaffolds facilitated ESC and iPS cell differentiation toward both urothelial and smooth muscle lineages in response to all trans retinoic acid as assessed by induction of uroplakin and contractile gene and protein expression. These results

  19. Evaluation of an interlaboratory comparison of the chemical assay of U, Th, oxide coated particles

    International Nuclear Information System (INIS)

    Tamberg, T.; Thiele, D.; Brodda, B.G.

    1981-09-01

    The prototype reactor THTR in Schmehausen (Germany, F.R.) burns a (Th,U)O 2 nuclear fuel using 93% enriched uranium. This material is particularly Safeguards sensitive. It was therefore desirable for the Safeguards Analytical Laboratory (SAL) and other laboratories of the Agency Network to collect experience and test their performance in the analysis of such materials. Support was requested from the ''Joint Programme between the IAEA and the Federal Republic of Germany for the Development of Safeguards Techniques'' to perform, as a first step, an interlaboratory comparison of the chemical assay of U and Th in pyrocarbon-coated BISO-type fuel particles. Such an intercomparison was organized under the auspices of the Institut fuer Chemische Technologie (ICT) of the Kernforschungsanlage Juelich GmbH (KFA). SAL prepared a statistical evaluation of the results which was discussed in Vienna in June 1980. The objective of the project was to define the state of the art in the chemical assay of U-Th fuels and the analytical requirements for the sampling of materials of major interest to Agency Safeguards at present

  20. Evaluation of extractant-coated magnetic microparticles for the recovery of hazardous metals from waste solution

    International Nuclear Information System (INIS)

    Kaminski, M. D.

    1998-01-01

    A magnetically assisted chemical separation (MACS) process was developed earlier at Argonne National Laboratory (ANL). This compact process was designed for the separation of transuranics (TRU) and radionuclides from the liquid waste streams that exist at many DOE sites, with an overall reduction in waste volume requiring disposal. The MACS process combines the selectivity afforded by solvent extractant/ion exchange materials with magnetic separation to provide an efficient chemical separation. Recently, the MACS process has been evaluated with acidic organophosphorus extractants for hazardous metal recovery from waste solutions. Moreover, process scale-up design issues have been addressed with respect to particle filtration and recovery. Two acidic organophosphorus compounds have been investigated for hazardous metal recovery, bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanexreg-sign 272) and bis(2,4,4-trimethylpentyl) dithiophosphinic acid (Cyanexreg-sign 301). Coated onto magnetic microparticles, these extractants demonstrated superior recovery of hazardous metals from solution, relative to what was expected on the basis of results from solvent extraction experiments. The results illustrate the diverse applications of MACS technology for dilute waste streams. Preliminary process scale-up experiments with a high-gradient magnetic separator at Oak Ridge National Laboratory have revealed that very low microparticle loss rates are possible

  1. Nondestructive Evaluation of Friction Stir-Welded Aluminum Alloy to Coated Steel Sheet Lap Joint

    Science.gov (United States)

    Das, H.; Kumar, A.; Rajkumar, K. V.; Saravanan, T.; Jayakumar, T.; Pal, Tapan Kumar

    2015-11-01

    Dissimilar lap joints of aluminum sheet (AA 6061) of 2 mm thickness and zinc-coated steel sheet of 1 mm thickness were produced by friction stir welding with different combinations of rotational speed and travel speed. Ultrasonic C- and B-scanning, and radiography have been used in a complementary manner for detection of volumetric (cavity and flash) and planar (de bond) defects as the defects are in micron level. Advanced ultrasonic C-scanning did not provide any idea about the defects, whereas B-scanning cross-sectional image showed an exclusive overview of the micron-level defects. A digital x-ray radiography methodology is proposed for quality assessment of the dissimilar welds which provide three-fold increase in signal-to-noise ratio with improved defect detection sensitivity. The present study clearly shows that the weld tool rotational speed and travel speed have a decisive role on the quality of the joints obtained by the friction stir welding process. The suitability of the proposed NDE techniques to evaluate the joint integrity of dissimilar FSW joints is thus established.

  2. Evaluation of Nd-Loaded SnO2:F Films Coated via Spray Pyrolysis

    Science.gov (United States)

    Turgut, G.

    2018-07-01

    Thin layers of single (F)- and double (F/Nd)-incorporated tin oxide have been coated on glass substrate via spray pyrolysis. The structural, morphological, electrical, and optical features of F-incorporated samples were evaluated depending on the Nd loading. X-ray diffraction analysis revealed that samples had tetragonal tin oxide structure with (211) and (200) preferential directions. The crystallite size and strain values varied from 37.98 nm and 1.21 × 10-3 to 52.12 nm and 1.88 × 10-3. Scanning electron microscopy analysis showed that the samples consisted of pyramidal, polyhedral, and needle-shaped granules. The lowest sheet resistance value of 1.22 Ω was found for 1.8 at.% Nd + 25 at.% F-coloaded SnO2. However, the widest optical bandgap of 4.01 eV was observed for the single 25 at.% F-loaded sample. The Urbach tail and figure of merit also changed in the ranges of 664 meV to 1296 meV and 6.4 × 10-2 Ω-1 to 2.3 × 10-3 Ω-1, respectively. The results presented herein indicate that the character of F-doped tin oxide films can be controlled by Nd loading and that these films could be useful for technological applications.

  3. Column study for the evaluation of the transport properties of polyphenol-coated nanoiron.

    Science.gov (United States)

    Mystrioti, C; Papassiopi, N; Xenidis, A; Dermatas, D; Chrysochoou, M

    2015-01-08

    Injection of a nano zero valent iron (nZVI) suspension in the subsurface is a remedial option for obtaining the in situ reduction and immobilization of hexavalent chromium in contaminated aquifers. Prerequisite for the successful implementation of this technology is that the nanoparticles form a stable colloidal suspension with good transport properties when delivered in the subsurface. In this study we produced stable suspensions of polyphenol-coated nZVI (GT-nZVI) and we evaluated their transport behavior through representative porous media. Two types of porous materials were tested: (a) silica sand as a typical inert medium and (b) a mixture of calcareous soil and sand. The transport of GT-nZVI through the sand column was effectively described using a classic 1-D convection-dispersion flow equation (CDE) in combination with the colloid filtration theory (CFT). The calculations indicate that nZVI travel distance will be limited in the range 2.5-25cm for low Darcy velocities (0.1-1m/d) and in the order of 2.5m at higher velocities (10m/d). The mobility of GT-nZVI suspension in the soil-sand column is lower and is directly related to the progress of the neutralization reactions between the acidic GT-nZVI suspension and soil calcite. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Wear evaluation of WC inserts coated with TiN/TiAlN multinanolayers

    OpenAIRE

    Moreno, L. H.; Ciacedo, J. C.; Martinez, F.; Bejarano, G.; Battaille, T. S.; Prieto, P.

    2010-01-01

    TiN/TiAlN multilayers were deposited by radio frequency, r.f., reactive magnetron sputtering by using titanium and aluminum targets with 10 cm diameter and 99.99% purity in an argon/nitrogen atmosphere, applying a substrate temperature of 300 ºC. WC inserts were used as substrates to improve the mechanical and tribological properties of TiN/TiAlN multilayered coatings compared to other types of coatings like TiAlN monolayers and to manage greater efficiency of these coatings in different indu...

  5. Nondestructive evaluation of a cermet coating using ultrasonic and eddy current techniques

    International Nuclear Information System (INIS)

    Roge, B.; Fahr, A.; Giguere, J.S.R.; McRae, K.I.

    2002-01-01

    This paper describes a series of experiments conducted to characterize cermet coatings using conventional ultrasonic and eddy current techniques as well as an ultrasonic leaky surface wave method. The results demonstrate the ability of these techniques to detect the presence of artificial defects on the surface or beneath the surface of the coating. In addition, ultrasonic tests in particular ultrasonic leaky surface waves demonstrate the ability to detect the presence of manufacturing flaws. Ultrasonic time-of-flight and eddy current quadrature measurements also show sensitivity to variations in coating thickness

  6. Anticorrosive organic/inorganic hybrid coatings

    Science.gov (United States)

    Gao, Tongzhai

    evaluated by electrochemical impedance spectroscopy (EIS) and the results showed that 10 wt% pigmentation improved the corrosion resistance of the entire coating system. The effect of pigmentation on epoxide/polysiloxane hybrid coatings was also investigated. The epoxide was successfully modified using 3-(triethoxysilyl) propyl isocyanate (TEOSPI) as indicated by FTIR and NMR. Good dispersion of the pigment particles was achieved as revealed by the SEM images. The tensile modulus, tensile strength, pencil hardness and thermal stability of the hybrid coatings were improved while the flexibility and pull-off adhesion were deteriorated when increasing PVC.

  7. Preparation of Cu–Ni–Fe alloy coating and its evaluation on corrosion behavior in 3.5% NaCl solution

    International Nuclear Information System (INIS)

    Zhou, Qiongyu; Jiang, Jibo; Zhong, Qingdong; Wang, Yi; Li, Ke; Liu, Huijuan

    2013-01-01

    Highlights: ► An uniform Cu–Ni–Fe alloy coating constituted of homogenous γ-phases was prepared on the surface of low-carbon steel. ► The increase of Ni has a significant promotion to produce a uniform and homogenous Cu–Ni–Fe alloy coating. ► Electrochemical test results indicated the excellent corrosion resistance of the coating with high Ni content. ► EIS test and results demonstrated the surface homogeneity or compactness of the coating with high Ni content. -- Abstract: In this paper, an attempt had been made to prepare a Cu–Ni–Fe alloy coating for improving the corrosion resistance of the low-carbon steel. The surface heat treatment of coated low-carbon steel was performed at 1000 °C for 3 h under hydrogen atmosphere. The structure and microstructure of coatings was separately analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The corrosion resistance of the samples was evaluated by potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy (EIS). Results indicated that a compact alloy coating was formed on the surface of low-carbon steel and the Ni content had a prodigious impact to the microstructure, composition and structure of Cu–Ni–Fe alloy coating. Apart from that, significant improvements in corrosion resistance were achieved by using the Cu–Ni–Fe alloy coating, which constituting of homogeneous γ-phases

  8. The applications of VIP 397/418 bulbs in free radical white pigmented coatings: UV curing evaluation for different free radical white pigmented formulations (I)

    International Nuclear Information System (INIS)

    Rong Bao; McCartney, R.

    1999-01-01

    White pigmented coatings have gained commercial success using a Gallium doped microwave F600-V bulb. A novel VIP 397/418 bulb has been made recently, by Fusion UV Systems, to increase UV curing efficiency of white pigmented coatings. Previous research work has shown that the VIP 397/418 bulb can cure cationic white pigmented coatings 40-60% faster than a F600-V bulb. Further evaluations of free radical white pigmented coatings have produced significant data indicating that better physical properties (40-50%) or higher cure speeds (50%) can be obtained by using the VIP 397/418 bulb than a F600-V bulb

  9. Evaluation of antibacterial, angiogenic, and osteogenic activities of green synthesized gap-bridging copper-doped nanocomposite coatings

    Directory of Open Access Journals (Sweden)

    Huang D

    2017-10-01

    Full Text Available Dan Huang,1 Kena Ma,1,2 Xinjie Cai,1,2 Xu Yang,3 Yinghui Hu,1 Pin Huang,1 Fushi Wang,1 Tao Jiang,1,2 Yining Wang1,2 1The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei- MOST & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, 2Department of Prosthodontics, Hospital of Stomatology, Wuhan University, Wuhan, China; 3Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, USA Abstract: Titanium (Ti and its alloys have been widely used in clinics for years. However, their bio-inert surface challenges application in patients with compromised surgical conditions. Numerous studies were conducted to modify the surface topography and chemical composition of Ti substrates, for the purpose of obtaining antibacterial, angiogenic, and osteogenic activities. In this study, using green electrophoretic deposition method, we fabricated gap-bridging chitosan-gelatin (CSG nanocomposite coatings incorporated with different amounts of copper (Cu; 0.01, 0.1, 1, and 10 mM for Cu I, II, III, and IV groups, respectively on the Ti substrates. Physicochemical characterization of these coatings confirmed that Cu ions were successfully deposited into the coatings in a metallic status. After rehydration, the coatings swelled by 850% in weight. Mechanical tests verified the excellent tensile bond strength between Ti substrates and deposited coatings. All Cu-containing CSG coatings showed antibacterial property against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. The antibacterial property was positively correlated with the Cu concentration. In vitro cytocompatibility evaluation demonstrated that activities of bone marrow stromal cells were not impaired on Cu-doped coatings except for the Cu IV group. Moreover, enhanced angiogenic and osteogenic activities were observed on Cu II and Cu III groups. Overall, our results

  10. Evaluation of seed coating formulations of Trichoderma harzianum on cucumber seeds against pre- and post-emergence damping-off caused by Pythium ultimum

    Science.gov (United States)

    Seed coating formulations of Trichoderma harzianum were evaluated on cucumber seeds to control pre- and post-emergence damping-off caused by Pythium ultimum in greenhouse studies. Results showed that coating formulation H reduced the disease incidence significantly, and had the potential for commer...

  11. Implementation of TiAIN and CrN coatings and ion implantation in the modern plastics moulding industry

    International Nuclear Information System (INIS)

    Bienk, E.J.; Mikkelsen, N.J.

    1997-01-01

    Two methods of surface improvement widely used in the modern plastics industry are compared, with a view to improving productivity and product quality. Ion implantation of plastics and physical vapour deposition coatings both offer surface engineering advantages. Each method is described and evaluated with reference to plastics moulding. TiAIN coatings are used to protect hard bulk materials, subjected to evenly distributed loads. The more ductile CrN coatings are used for softer materials which give less support to the coatings. (UK)

  12. Evaluation of the effects of water hardness and chemical pollutants on the zooplankton community in uranium mining lakes with acid mine drainage

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, H.; Ferrari, C.; Nascimento, M.R. [Brazilian Nulcear Energy Commission/Pocos de Caldas Laboratory (Brazil); Rodgher, S. [Universidade Estadual Paulista Julio de Mesquita Filho/Science and Technology Institute (Brazil); Wisniewski, M.J. [Alfenas Federal University/Limnology Laboratory (Brazil)

    2014-07-01

    Several mining lakes are characterized by the inorganic pollution of its waters, known as acid mine drainage (AMD). The current study was developed in order to evaluate the effect of water hardness and chemical pollutants on the richness and density of the zoo-planktonic community species. A seasonal study was conducted in a uranium mining lake affected by AMD. In environmental conditions of extremely high hardness water values (960.3 to 1284,9 mg/l), zoo-planktonic species have indicated resistance to the combined effect of elevated average concentrations of chemical pollutants such as Al (81.9 mg/l), Zn (15.5 mg/l), Mn (102.8 mg/l), U (2.9 mg/l) and low pH values (average = 3.8). Thus, in environments of extreme chemical conditions, such as a uranium mining lake affected by AMD, the hardness showed to be the best predictor of the zoo-planktonic community richness, indicating a protective effect of ions Ca{sup +2} over in special to Bosminopsis deitersi, Bosmina sp., Keratella americana and K. cochlearis. Document available in abstract form only. (authors)

  13. The Effect of Bias Voltage and Gas Pressure on the Structure, Adhesion and Wear Behavior of Diamond Like Carbon (DLC Coatings With Si Interlayers

    Directory of Open Access Journals (Sweden)

    Liam Ward

    2014-04-01

    Full Text Available In this study diamond like carbon (DLC coatings with Si interlayers were deposited on 316L stainless steel with varying gas pressure and substrate bias voltage using plasma enhanced chemical vapor deposition (PECVD technology. Coating and interlayer thickness values were determined using X-ray photoelectron spectroscopy (XPS which also revealed the presence of a gradient layer at the coating substrate interface. Coatings were evaluated in terms of the hardness, elastic modulus, wear behavior and adhesion. Deposition rate generally increased with increasing bias voltage and increasing gas pressure. At low working gas pressures, hardness and modulus of elasticity increased with increasing bias voltage. Reduced hardness and modulus of elasticity were observed at higher gas pressures. Increased adhesion was generally observed at lower bias voltages and higher gas pressures. All DLC coatings significantly improved the overall wear resistance of the base material. Lower wear rates were observed for coatings deposited with lower bias voltages. For coatings that showed wear tracks considerably deeper than the coating thickness but without spallation, the wear behavior was largely attributed to deformation of both the coating and substrate with some cracks at the wear track edges. This suggests that coatings deposited under certain conditions can exhibit ultra high flexible properties.

  14. Evaluation of the Texas tier system for seal coat binder specification.

    Science.gov (United States)

    2012-09-01

    The Texas Department of Transportation (TxDOT) instituted a change in their seal coat binder specification in 2010 which allowed districts to select multiple binders within specified traffic levels or tiers for the purposes of allowing contractors to...

  15. Evaluation of Various Tack Coat Materials Using Interface Shear Device and Recommendations on a Simplified Device

    Science.gov (United States)

    2017-12-01

    The performance of pavement interface bonds affects the integrity of pavement structures. In current practice, tack coats are used to ensure sufficient bonding between asphalt concrete (AC) layers as well as AC and concrete or aggregate base layers. ...

  16. Evaluation of Galvanized and Galvalume/Paint Duplex Coating Systems for Steel Building Panels

    National Research Council Canada - National Science Library

    Race, Timothy

    2002-01-01

    ...) or silicone modified polyester (SMP). Specimens having these coating systems were subjected to ASTM B 117, conventional salt spray exposure testing and ASTM D 5894 Testing in the laboratory, which combines the environmental effects...

  17. 96X Screen-Printed Gold Electrode Platform to Evaluate Electroactive Polymers as Marine Antifouling Coatings.

    Science.gov (United States)

    Brisset, Hugues; Briand, Jean-François; Barry-Martinet, Raphaëlle; Duong, The Hy; Frère, Pierre; Gohier, Frédéric; Leriche, Philippe; Bressy, Christine

    2018-04-17

    Several alternatives are currently investigated to prevent and control the natural process of colonization of any seawater submerged surfaces by marine organisms. Since few years we develop an approach based on addressable electroactive coatings containing conducting polymers or polymers with lateral redox groups. In this article we describe the use of a screen-printed plate formed by 96 three-electrode electrochemical cells to assess the potential of these electroactive coatings to prevent the adhesion of marine bacteria. This novel platform is intended to control and record the redox properties of the electroactive coating in each well during the bioassay (15 h) and to allow screening its antiadhesion activity with enough replicates to support significant conclusions. Validation of this platform was carried out with poly(ethylenedioxythiophene) (PEDOT) as electroactive coating obtained by electropolymerization of EDOT monomer in artificial seawater electrolyte on the working electrode of each electrochemical cell of the 96-well microplate.

  18. Evaluation of Hydrogen Cracking in Weld Metal Deposited using Cellulosic-Coated Electrodes

    Science.gov (United States)

    2009-06-16

    Cellulosic-coated electrodes (primarily AWS EXX10-type) are traditionally used for "stovepipe" welding of pipelines because they are well suited for deposition of pipeline girth welds and are capable of high deposition rates when welding downhill. De...

  19. Splice performance evaluation of enamel-coated rebar for structural safety.

    Science.gov (United States)

    2014-07-01

    This report summarizes the findings and results from an experimental study of vitreous enamel coating effects on the bond : strength between deformed rebar and normal strength concrete. A total of 24 beam splice specimens were tested under four-point...

  20. Corrosion evaluation of zirconium doped oxide coatings on aluminum formed by plasma electrolytic oxidation.

    Science.gov (United States)

    Bajat, Jelena; Mišković-Stanković, Vesna; Vasilić, Rastko; Stojadinović, Stevan

    2014-01-01

    The plasma electrolytic oxidation (PEO) of aluminum in sodium tungstate (Na(2)WO(4) · (2)H(2)O) and Na(2)WO(4) · (2)H(2)O doped with Zr was analyzed in order to obtain oxide coatings with improved corrosion resistance. The influence of current density in PEO process and anodization time was investigated, as well as the influence of Zr, with the aim to find out how they affect the chemical content, morphology, surface roughness, and corrosion stability of oxide coatings. It was shown that the presence of Zr increases the corrosion stability of oxide coatings for all investigated PEO times. Evolution of EIS spectra during the exposure to 3% NaCl, as a strong corrosive agent, indicated the highest corrosion stability for PEO coating formed on aluminum at 70 mA/cm(2) for 2 min in a zirconium containing electrolyte.

  1. Evaluation of bone loss in antibacterial coated dental implants: An experimental study in dogs

    DEFF Research Database (Denmark)

    Gallardo, Maria Godoy; Manzanares-Céspedes, Maria Cristina; Sevilla, Pablo

    2016-01-01

    _Ag (silver electrodeposition treatment, 10 units), and Ti_TSP (silanization treatment, 10 units). Coated implants were characterized by scanning electron microscopy, interferometry and X-ray photoelectron spectroscopy. Two months after implant insertion, experimental peri-implantitis was initiated...

  2. Evaluation of Volatile Organic Compound Emissions from Line-X XS-350 Polymer Coating

    National Research Council Canada - National Science Library

    Henley, M

    2002-01-01

    The use of Line-X XS-350 polymer as an interior retrofit coating for occupied building Structures to improve their blast resistance has raised a major concern by potential users of the polymer retrofit technology...

  3. Characterization and coating stability evaluation of nickel-titanium orthodontic esthetic wires: an in vivo study

    Directory of Open Access Journals (Sweden)

    Nina ARGALJI

    2017-08-01

    Full Text Available Abstract The objective of this study was to compare coating dimensions and surface characteristics of two different esthetic covered nickel-titanium orthodontic rectangular archwires, as-received from the manufacturer and after oral exposure. The study was designed for comparative purposes. Both archwires, as-received from the manufacturer, were observed using a stereomicroscope to measure coating thickness and inner metallic dimensions. The wires were also exposed to oral environment in 11 orthodontic active patients for 21 days. After removing the samples, stereomicroscopy images were captured, coating loss was measured and its percentage was calculated. Three segments of each wire (one as-received and two after oral exposure were observed using scanning electron microscopy for a qualitative analysis of the labial surface of the wires. The Lilliefors test and independent t-test were applied to verify normality of data and statistical differences between wires, respectively. The significance level adopted was 0.05. The results showed that the differences between the wires while comparing inner height and thickness were statistically significant (p < 0.0001. In average, the most recently launched wire presented a coating thickness twice that of the control wire, which was also a statistically significant difference. The coating loss percentage was also statistically different (p = 0.0346 when the latest launched wire (13.27% was compared to the control (29.63%. In conclusion, the coating of the most recent wire was thicker and more uniform, whereas the control had a thinner coating on the edges. After oral exposure, both tested wires presented coating loss, but the most recently launched wire exhibited better results.

  4. Characterization and coating stability evaluation of nickel-titanium orthodontic esthetic wires: an in vivo study.

    Science.gov (United States)

    Argalji, Nina; Silva, Eduardo Moreira da; Cury-Saramago, Adriana; Mattos, Claudia Trindade

    2017-08-21

    The objective of this study was to compare coating dimensions and surface characteristics of two different esthetic covered nickel-titanium orthodontic rectangular archwires, as-received from the manufacturer and after oral exposure. The study was designed for comparative purposes. Both archwires, as-received from the manufacturer, were observed using a stereomicroscope to measure coating thickness and inner metallic dimensions. The wires were also exposed to oral environment in 11 orthodontic active patients for 21 days. After removing the samples, stereomicroscopy images were captured, coating loss was measured and its percentage was calculated. Three segments of each wire (one as-received and two after oral exposure) were observed using scanning electron microscopy for a qualitative analysis of the labial surface of the wires. The Lilliefors test and independent t-test were applied to verify normality of data and statistical differences between wires, respectively. The significance level adopted was 0.05. The results showed that the differences between the wires while comparing inner height and thickness were statistically significant (p wire presented a coating thickness twice that of the control wire, which was also a statistically significant difference. The coating loss percentage was also statistically different (p = 0.0346) when the latest launched wire (13.27%) was compared to the control (29.63%). In conclusion, the coating of the most recent wire was thicker and more uniform, whereas the control had a thinner coating on the edges. After oral exposure, both tested wires presented coating loss, but the most recently launched wire exhibited better results.

  5. Evaluating the Properties of High-Temperature and Low-Temperature Wear of TiN Coatings Deposited at Different Temperatures

    Directory of Open Access Journals (Sweden)

    B. Khorrami Mokhori

    2017-02-01

    Full Text Available In this research titanium nitride (TiN films were prepared by plasma assisted chemical vapor deposition using TiCl4, H2, N2 and Ar on the AISI H13 tool steel. Coatings were deposited during different substrate temperatures (460°C, 480 ° C  and 510 °C. Wear tests were performed in order to study the acting wear mechanisms in the high(400 °C and low (25 °C temperatures by ball on disc method. Coating structure and chemical composition were characterized using scanning electron microscopy, microhardness and X-ray diffraction. Wear test result was described in ambient temprature according to wear rate. It was evidenced that the TiN coating deposited at 460 °C has the least weight loss with the highest hardness value. The best wear resistance was related to the coating with the highest hardness (1800 Vickers. Wear mechanisms were observed to change by changing wear temperatures. The result of wear track indicated that low-temprature wear has surface fatigue but high-temperature wear showed adhesive mechanism.

  6. Evaluation of mechanical hardness and fracture toughness of Co and Al co-doped ZnO

    International Nuclear Information System (INIS)

    Siddheswaran, R.; Mangalaraja, R.V.; Avila, Ricardo E.; Manikandan, D.; Esther Jeyanthi, C.; Ananthakumar, S.

    2012-01-01

    Combustion synthesized nanocrystalline Co and Al co-doped ZnO powders [(Zn 1−x−y Co x Al y O; x=0.04, 0.03, 0.02; y=0.01, 0.02, 0.03)] were fabricated into cylindrical discs by uni-axial pressing and sintered intentionally at 1000 °C for 2 h to assess the mechanical performance. The crystallinity of the pure and doped ZnO was confirmed by X-ray diffraction analysis. The microstructures of the sintered samples were investigated by scanning electron microscopy (SEM) to examine the density, porosity, grain size and its distribution. Grains of 0.5–3 μm were observed for the samples sintered at 1000 °C. The mechanical properties such as micro-hardness, fracture toughness and strain hardening co-efficient were investigated by the Vickers indentation method. It was found that the crack mode observed during the indentation on the samples belongs to median cracks under a load of 19.6 N. Also, the hardness was enhanced with increasing mol% of Co, while the trend was reversed with the increase of Al content. In addition, the strain hardening coefficient and fracture toughness were calculated using the indentation data.

  7. Evaluating a Health Belief Model-Based Educational Program for School Injury Prevention among Hard-of-Hearing/Deaf High School Students

    Directory of Open Access Journals (Sweden)

    Fatemeh Vejdani-Aram

    2015-03-01

    Full Text Available Background and Objectives: While all students are vulnerable to injuries, such vulnerability may even be higher in the deaf and hard-of-hearing students. Therefore, this study evaluated a health belief model-based educational program to prevent school injuries among deaf and hard-of-hearing high school students. Materials and Methods: This quasi-experimental study was conducted on all deaf and hard-of-hearing students who attended two special schools in Hamadan (Iran during 2014. They were randomly assigned to either the intervention group (n = 23 or the control group (n = 27. Data were collected using a self-report questionnaire containing items on demographic characteristics, constructs of the health belief model, and knowledge and preventive behaviors. In both groups, the questionnaires were filled out through interviews before and two months after the intervention. The intervention included distributing booklets and holding five educational sessions. Data were analyzed with paired t, independent t, chi square, and Fisher’s exact tests in SPSS16. Results: After the educational intervention, the mean scores of knowledge (P=0.002, preventive behaviors (P=0.001, and constructs of the health belief model, i.e. perceived severity (P=0.001, perceived benefits (P=0.001, self-efficacy (P=0.001, and cues to action (P=0.001, were significantly higher in the intervention group than in the control group. Conclusion: According to our findings, an educational intervention based on the health belief model can promote behaviors to prevent school injuries among deaf and hard-of-hearing students.

  8. Nanostructured diamond coatings for orthopaedic applications

    Science.gov (United States)

    CATLEDGE, S.A.; THOMAS, V.; VOHRA, Y.K.

    2013-01-01

    With increasing numbers of orthopaedic devices being implanted, greater emphasis is being placed on ceramic coating technology to reduce friction and wear in mating total joint replacement components, in order to improve implant function and increase device lifespan. In this chapter, we consider ultra-hard carbon coatings, with emphasis on nanostructured diamond, as alternative bearing surfaces for metallic components. Such coatings have great potential for use in biomedical implants as a result of their extreme hardness, wear resistance, low friction and biocompatibility. These ultra-hard carbon coatings can be deposited by several techniques resulting in a wide variety of structures and properties. PMID:25285213

  9. Evaluation of Antibacterial Effects of Silver-Coated Stainless Steel Orthodontic Brackets.

    Science.gov (United States)

    Arash, Valiollah; Keikhaee, Fatemeh; Rabiee, Sayed Mahmood; Rajabnia, Ramazan; Khafri, Soraya; Tavanafar, Saeid

    2016-01-01

    White spots and enamel demineralization around orthodontic brackets are among the most important complications resulting from orthodontic treatments. Since the antibacterial properties of metals and metallic particles have been well documented, the aim of this study was to assess the antibacterial effect of stainless steel orthodontic brackets coated with silver (Ag) particles. In this study, 40 standard metal brackets were divided into two groups of 20 cases and 20 controls. The brackets in the case group were coated with Ag particles using an electroplating method. Atomic force microscopy and scanning electron microscopy were used to assess the adequacy of the coating process. In addition, antibacterial tests, i.e., disk diffusion and direct contact tests were performed at three, six, 24, and 48 hours, and 15 and 30 days using a Streptococcus mutans strain. The results were analyzed using Student's t-test and repeated measures ANOVA. Analyses via SEM and AFM confirmed that excellent coatings were obtained by using an electroplating method. The groups exhibited similar behavior when subjected to the disk diffusion test in the agar medium. However, the bacterial counts of the Ag-coated brackets were, in general, significantly lower (PBrackets coated with Ag, via an electroplating method, exhibited antibacterial properties when placed in direct contact with Streptococcus mutans. This antibacterial effect persisted for 30 days after contact with the bacteria.

  10. Application of a radiotelemetric system to evaluate the performance of enteric coated and plain aspirin tablets.

    Science.gov (United States)

    Lui, C Y; Oberle, R; Fleisher, D; Amidon, G L

    1986-05-01

    The bioavailability of enteric coated and plain aspirin tablets was studied in four beagle dogs. Blood sampling for enteric coated tablets was planned with the aid of a radiotelemetric system. The release of aspirin from its dosage form was detected by monitoring the change in intestinal pH. Aspirin and salicylic acid levels in plasma obtained from the enteric coated dosage form exhibited familiar concentration versus time absorption profiles. Variation in the plasma concentrations of these two compounds within each dog studied (four runs each) was relatively small when time zero was adjusted to the commencement of tablet dissolution. The plasma levels obtained from plain aspirin (three runs each), however, show atypical absorption. The estimated absolute bioavailability was 0.432 +/- 0.0213 and 0.527 +/- 0.0260 for enteric coated and plain aspirin, respectively. Other pharmacokinetic parameters for these two dosage forms such as the highest observed plasma concentration (Cmax) (10.9 +/- 0.535 microgram/mL versus 13.6 +/- 1.88 micrograms/mL) and the time to reach Cmax (tmax) (26.6 +/- 1.94 min versus 31.0 +/- 7.04 min) agree well. The mean values for gastric emptying time, in vivo coating dissolution time, and in vivo disintegration/dissolution time of the tablet core for enteric coated aspirin are 48.7 +/- 7.23 min, 44.3 +/- 3.80 min, and 34.7 +/- 2.04 min, respectively.

  11. A Comparative Study of the Microstructure, Mechanical Properties and Corrosion Resistance of Ni- or Fe- Based Composite Coatings by Laser Cladding

    Science.gov (United States)

    Wan, M. Q.; Shi, J.; Lei, L.; Cui, Z. Y.; Wang, H. L.; Wang, X.

    2018-04-01

    Ni- and Fe-based composite coatings were laser cladded on 40Cr steel to improve the surface mechanical property and corrosion resistance, respectively. The microstructure and phase composition were analyzed by x-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) equipped with an energy-dispersive spectrometer (EDS). The micro-hardness, tribological properties and electrochemical corrosion behavior of the coatings were evaluated. The results show that the thickness of both the coatings is around 0.7 mm, the Ni-based coating is mainly composed of γ-(Ni, Fe), FeNi3, Ni31Si12, Ni3B, CrB and Cr7C3, and the Fe-based coating is mainly composed of austenite and (Fe, Cr)7C3. Micro-hardness of the Ni-based composite coating is about 960 HV0.3, much higher than that of Fe-based coating (357.4 HV0.3) and the 40Cr substrate (251 HV0.3). Meanwhile, the Ni-based composite coating possesses better wear resistance than the Fe-based coating validated by the worn appearance and the wear loss. Electrochemical results suggested that Ni-based coating exhibited better corrosion resistance than the Fe-based coating. The 40Cr substrate could be well protected by the Ni-based coating.

  12. Development of Ceramic Coating on Metal Substrate using Industrial Waste and Ore Minerals

    Science.gov (United States)

    Bhuyan, S. K.; Thiyagarajan, T. K.; Mishra, S. C.

    2017-02-01

    The technological advancement in modern era has a boon for enlightening human life; but also is a bane to produce a huge amount of (industrial) wastes, which is of great concern for utilization and not to create environmental threats viz. polution etc. In the present piece of research work, attempts have been made to utilize fly ash (wastes of thermal power plants) and along with alumina bearing ore i.e. bauxite, for developing plasma spray ceramic coatings on metals. Fly ash and with 10 and 20% bauxite addition is used to deposit plasma spray coatings on a metal substrate. The surface mor