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Sample records for wear resistant components

  1. Development of wear resistant ceramic coatings for diesel engine components

    Energy Technology Data Exchange (ETDEWEB)

    Haselkorn, M.H. (Caterpillar, Inc., Peoria, IL (United States))

    1992-04-01

    Improved fuel economy and a reduction of emissions can be achieved by insulation of the combustion chamber components to reduce heat rejection. However, insulating the combustion chamber components will also increase the operating temperature of the piston ring/cylinder liner interface from approximately 150{degree}C to over 300{degree}C. Existing ring/liner materials can not withstand these higher operating temperatures and for this reason, new materials need to be developed for this critical tribological interface. The overall goal of this program is the development of piston ring/cylinder liner material pairs which would be able to provide the required friction and wear properties at these more severe operating conditions. More specifically, this program first selected, and then evaluated, potential d/wear resistant coatings which could be applied to either piston rings an or cylinder liners and provide, at 350{degree}C under lubricated conditions, coefficients of friction below 0.1 and wear rates of less than 25 {times} lO{sup {minus}6} mm/hour. The processes selected for applying the candidate wear resistant coatings to piston rings and/or cylinder liners were plasma spraying, chemical vapor, physical vapor and low temperature arc vapor deposition techniques as well as enameling techniques.

  2. FIBROUS MONOLITH WEAR RESISTANT COMPONENTS FOR THE MINING INDUSTRY

    Energy Technology Data Exchange (ETDEWEB)

    Kenneth L. Knittel

    2005-05-09

    The work performed on this program was to develop wear resistant, tough FM composite materials with efforts focused on WC-Co based FM systems. The materials were developed for use in mining industry wear applications. Components of interest were drill bit inserts for drilling blast holes. Other component applications investigated included wear plates for a variety of equipment such as pit shovels, wear surfaces for conveyors, milling media for ball milling operations, hydrocyclone cones, grader blades and dozer teeth. Cross-cutting technologies investigated included hot metal extrusion dies, drill bits for circuit board fabrication, cutting tools for cast iron and aluminum machining. An important part of the work was identification of the standard materials used in drilling applications. A materials trade study to determine those metals and ceramics used for mining applications provided guidance for the most important materials to be investigated. WC-Co and diamond combinations were shown to have the most desirable properties. Other considerations such as fabrication technique and the ability to consolidate shifted the focus away from diamond materials and toward WC-Co. Cooperating partners such as Kennametal and Kyocera assisted with supplies, evaluations of material systems, fabricated parts and suggestions for cross-cutting technology applications for FM architectures. Kennametal provided the raw materials (WC-Co and Al-TiCN powders) for the extent of the material evaluations. Kyocera shared their research into various FM systems and provided laboratory testing of fabricated materials. Kyocera also continued research of the FM systems with the intention of developing commercial markets for a variety of applications. The continued development of FM technology by Kyocera is seen as a direct result of the cooperation established under this funding. Kyocera has a specific interest in the commercial development of the FM technology and have licensed it and have paid

  3. Development of wear resistant ceramic coatings for diesel engine components. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Haselkorn, M.H. [Caterpillar, Inc., Peoria, IL (United States)

    1992-04-01

    Improved fuel economy and a reduction of emissions can be achieved by insulation of the combustion chamber components to reduce heat rejection. However, insulating the combustion chamber components will also increase the operating temperature of the piston ring/cylinder liner interface from approximately 150{degree}C to over 300{degree}C. Existing ring/liner materials can not withstand these higher operating temperatures and for this reason, new materials need to be developed for this critical tribological interface. The overall goal of this program is the development of piston ring/cylinder liner material pairs which would be able to provide the required friction and wear properties at these more severe operating conditions. More specifically, this program first selected, and then evaluated, potential d/wear resistant coatings which could be applied to either piston rings an or cylinder liners and provide, at 350{degree}C under lubricated conditions, coefficients of friction below 0.1 and wear rates of less than 25 {times} lO{sup {minus}6} mm/hour. The processes selected for applying the candidate wear resistant coatings to piston rings and/or cylinder liners were plasma spraying, chemical vapor, physical vapor and low temperature arc vapor deposition techniques as well as enameling techniques.

  4. Development of wear-resistant ceramic coatings for diesel engine components

    Energy Technology Data Exchange (ETDEWEB)

    Naylor, M.G.S. (Cummins Engine Co., Inc., Columbus, IN (United States))

    1992-06-01

    The tribological properties of a variety of advanced coating materials have been evaluated under conditions which simulate the piston ring -- cylinder liner environment near top ring reversal in a heavy duty diesel engine. Coated ring'' samples were tested against a conventional pearlitic grey cast iron liner material using a high temperature reciprocating wear test rig. Tests were run with a fresh CE/SF 15W40lubricant at 200 and 350{degrees}C, with a high-soot, engine-tested oil at 200{degrees}C and with no lubrication at 200{degrees}C. For lowest wear under boundary lubricated conditions, the most promising candidates to emerge from this study were high velocity oxy-fuel (HVOF) Cr{sub 3} C{sub 2} - 20% NiCr and WC - 12% Co cermets, low temperature arc vapor deposited (LTAVD) CrN and plasma sprayed chromium oxides. Also,plasma sprayed Cr{sub 2}O{sub 3} and A1{sub 2}O{sub 3}-ZrO{sub 2} materials were found to give excellent wear resistance in unlubricated tests and at extremely high temperatures (450{degrees}C) with a syntheticoil. All of these materials would offer substantial wear reductions compared to the conventional electroplated hard chromium ring facing and thermally sprayed metallic coatings, especially at high temperatures and with high-soot oils subjected to degradation in diesel environments. The LTAVD CrN coating provided the lowest lubricated wear rates of all the materials evaluated, but may be too thin (4 {mu}m) for use as a top ring facing. Most of the coatings evaluated showed higher wear rates with high-soot, engine-tested oil than with fresh oil, with increases of more than a factor of ten in some cases. Generally, metallic materials were found to be much more sensitive to soot/oil degradation than ceramic and cermet coatings. Thus, decreased soot sensitivity'' is a significant driving force for utilizing ceramic or cermet coatings in diesel engine wear applications.

  5. Low friction wear resistant graphene films

    Science.gov (United States)

    Sumant, Anirudha V.; Berman, Diana; Erdemir, Ali

    2017-02-07

    A low friction wear surface with a coefficient of friction in the superlubric regime including graphene and nanoparticles on the wear surface is provided, and methods of producing the low friction wear surface are also provided. A long lifetime wear resistant surface including graphene exposed to hydrogen is provided, including methods of increasing the lifetime of graphene containing wear surfaces by providing hydrogen to the wear surface.

  6. Wear resistance of hydrophobic surfaces

    Science.gov (United States)

    Martinez, MA; Abenojar, J.; Pantoja, M.; López de Armentia, S.

    2017-05-01

    Nature has been an inspiration source to develop artificial hydrophobic surfaces. During the latest years the development of hydrophobic surfaces has been widely researched due to their numerous ranges of industrial applications. Industrially the use of hydrophobic surfaces is being highly demanded. This is why many companies develop hydrophobic products to repel water, in order to be used as coatings. Moreover, these coating should have the appropriated mechanical properties and wear resistance. In this work wear study of a hydrophobic coating on glass is carried out. Hydrophobic product used was Sika Crystal Dry by Sika S.A.U. (Alcobendas, Spain). This product is currently used on car windshield. To calculate wear resistance, pin-on-disk tests were carried out in dry and water conditions. The test parameters were rate, load and sliding distance, which were fixed to 60 rpm, 5 N and 1000 m respectively. A chamois was used as pin. It allows to simulate a real use. The friction coefficient and loss weight were compared to determinate coating resistance

  7. Sliding wear resistance of iron aluminides

    Indian Academy of Sciences (India)

    Unknown

    ordered intermetallic alloy (Johnson et al 1990, 1994,. 1996; Maupin et al 1992, 1993; Tu and Liu 1997; Kim and Kim 1998). Maupin et al (1992, 1993) had shown that the Fe3Al alloy having DO3 structure possesses mar- ginally lower wear rate than those with B2 structure. The wear resistance of Fe3Al alloy was found to ...

  8. Critical component wear in heavy duty engines

    CERN Document Server

    Lakshminarayanan, P A

    2011-01-01

    The critical parts of a heavy duty engine are theoretically designed for infinite life without mechanical fatigue failure. Yet the life of an engine is in reality determined by wear of the critical parts. Even if an engine is designed and built to have normal wear life, abnormal wear takes place either due to special working conditions or increased loading.  Understanding abnormal and normal wear enables the engineer to control the external conditions leading to premature wear, or to design the critical parts that have longer wear life and hence lower costs. The literature on wear phenomenon r

  9. Development of wear-resistant ceramic coatings for diesel engine components. Volume 1, Coating development and tribological testing: Final report: DOE/ORNL Ceramic Technology Project

    Energy Technology Data Exchange (ETDEWEB)

    Naylor, M.G.S. [Cummins Engine Co., Inc., Columbus, IN (United States)

    1992-06-01

    The tribological properties of a variety of advanced coating materials have been evaluated under conditions which simulate the piston ring -- cylinder liner environment near top ring reversal in a heavy duty diesel engine. Coated ``ring`` samples were tested against a conventional pearlitic grey cast iron liner material using a high temperature reciprocating wear test rig. Tests were run with a fresh CE/SF 15W40lubricant at 200 and 350{degrees}C, with a high-soot, engine-tested oil at 200{degrees}C and with no lubrication at 200{degrees}C. For lowest wear under boundary lubricated conditions, the most promising candidates to emerge from this study were high velocity oxy-fuel (HVOF) Cr{sub 3} C{sub 2} - 20% NiCr and WC - 12% Co cermets, low temperature arc vapor deposited (LTAVD) CrN and plasma sprayed chromium oxides. Also,plasma sprayed Cr{sub 2}O{sub 3} and A1{sub 2}O{sub 3}-ZrO{sub 2} materials were found to give excellent wear resistance in unlubricated tests and at extremely high temperatures (450{degrees}C) with a syntheticoil. All of these materials would offer substantial wear reductions compared to the conventional electroplated hard chromium ring facing and thermally sprayed metallic coatings, especially at high temperatures and with high-soot oils subjected to degradation in diesel environments. The LTAVD CrN coating provided the lowest lubricated wear rates of all the materials evaluated, but may be too thin (4 {mu}m) for use as a top ring facing. Most of the coatings evaluated showed higher wear rates with high-soot, engine-tested oil than with fresh oil, with increases of more than a factor of ten in some cases. Generally, metallic materials were found to be much more sensitive to soot/oil degradation than ceramic and cermet coatings. Thus, decreased ``soot sensitivity`` is a significant driving force for utilizing ceramic or cermet coatings in diesel engine wear applications.

  10. Wear Resistant Amorphous and Nanocomposite Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Racek, O

    2008-03-26

    Glass forming materials (critical cooling rate <10{sup 4}K.s{sup -1}) are promising for their high corrosion and wear resistance. During rapid cooling, the materials form an amorphous structure that transforms to nanocrystalline during a process of devitrification. High hardness (HV 1690) can be achieved through a controlled crystallization. Thermal spray process has been used to apply coatings, which preserves the amorphous/nanocomposite structure due to a high cooling rate of the feedstock particles during the impact on a substrate. Wear properties have been studied with respect to process conditions and feedstock material properties. Application specific properties such as sliding wear resistance have been correlated with laboratory tests based on instrumented indentation and scratch tests.

  11. Corrosive wear. Evaluation of wear and corrosive resistant materials; Noetningskorrosion. Utvaerdering av noetnings- och korrosionsbestaendiga material

    Energy Technology Data Exchange (ETDEWEB)

    Persson, H.; Hjertsen, D.; Waara, P.; Prakash, B.; Hardell, J.

    2007-12-15

    With a new purchase of a waste conveyer screw at hand, for the 'A-warehouse' at the combined power and heating plant at E.ON Norrkoeping, the request for improved construction materials was raised. The previous screw required maintenance with very short intervals due to the difficult operation conditions. With the new screw the expectation is to manage 6 months of operation without interruption. The environment for the screw has two main components that sets the demand on the materials, on one hand the corrosive products that comes along and which forms at digestion of the waste and on the other hand the abrasive content in the waste. The term of the mechanism is wear-corrosion and can give considerably higher material loss than the two mechanisms wear and corrosion separately. Combination of a strong corrosive environment together with extensive wear is something that we today have limited knowledge about. The overall objective of the project has been to establish better wear and corrosive resistant construction materials for a waste conveyer screw that will lead to reduced operational disturbance costs. The evaluation has been performed in both controlled laboratory environments and in field tests, which has given us a better understanding of what materials are more suitable in this tough environment and has given us a tool for future predictions of the wear rate of the different material. The new conveyer screw, installed in February 2007 and with which the field test have been performed, has considerably reduced the wear of the construction and the target of 6 month maintenance-free operation is met with this screw for all the evaluated materials. The wear along the screw varies very much and with a clear trend for all the materials to increase towards the feeding direction of the screw. As an example, the wear plate SS2377 (stainless duplex steel) has a useful life at the most affected areas that is calculated to be 1077 days of operation with the

  12. Adhesion and wear resistance of materials

    Science.gov (United States)

    Buckley, D. H.

    1986-01-01

    Recent studies into the nature of bonding at the interface between two solids in contact or a solid and deposited film have provided a better understanding of those properties important to the adhesive wear resistance of materials. Analytical and experimental progress are reviewed. For simple metal systems the adhesive bond forces are related to electronic wave function overlap. With metals in contact with nonmetals, molecular-orbital energy, and density of states, respectively can provide insight into adhesion and wear. Experimental results are presented which correlate adhesive forces measured between solids and the electronic surface structures. Orientation, surface reconstruction, surface segregation, adsorption are all shown to influence adhesive interfacial strength. The interrelationship between adhesion and the wear of the various materials as well as the life of coatings applied to substrates are discussed. Metallic systems addressed include simple metals and alloys and these materials in contact with themselves, both oxide and nonoxide ceramics, diamond, polymers, and inorganic coating compounds, h as diamondlike carbon.

  13. The Abrasive Wear Resistance of Chromium Cast Iron

    Directory of Open Access Journals (Sweden)

    Kopyciński D.

    2014-03-01

    Full Text Available The resistance of cast iron to abrasive wear depends on the metal abrasive hardness ratio. For example, hardness of the structural constituents of the cast iron metal matrix is lower than the hardness of ordinary silica sand. Also cementite, the basic component of unalloyed white cast iron, has hardness lower than the hardness of silica. Some resistance to the abrasive effect of the aforementioned silica sand can provide the chromium white cast iron containing in its structure a large amount of (Cr, Fe7C3 carbides characterised by hardness higher than the hardness of the silica sand in question. In the present study, it has been anticipated that the white cast iron structure will be changed by changing the type of metal matrix and the type of carbides present in this matrix, which will greatly expand the application area of castings under the harsh operating conditions of abrasive wear. Moreover, the study compares the results of abrasive wear resistance tests performed on the examined types of cast iron. Tests of abrasive wear resistance were carried out on a Miller machine. Samples of standard dimensions were exposed to abrasion in a double to-and-fro movement, sliding against the bottom of a trough filled with an aqueous abrasive mixture containing SiC + distilled water. The obtained results of changes in the sample weight were approximated with a power curve and shown further in the study.

  14. Wear-resistance of Aluminum Matrix Microcomposite Materials

    Directory of Open Access Journals (Sweden)

    M. Kandeva

    2011-03-01

    Full Text Available A procedure is developed for the study of wear of aluminum alloys AlSi7 obtained by casting, reinforced by TiC microparticles, before and after heat treatment. Tribological study is realized under conditions of friction on counterbody with fixed abrasive. Experimental results were obtained for mass wear, wear rate, wear intensity and wear-resistance of the alloys with different wt% of microparticles.

  15. Advanced Wear-resistant Nanocomposites for Increased Energy Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Cook, B. A.; Harringa, J. L.; Russel, A. M.

    2012-12-01

    This report summarizes the work performed by an Ames-led project team under a 4-year DOE-ITP sponsored project titled, 'Advanced Wear-resistant Nanocomposites for Increased Energy Efficiency.' The Report serves as the project deliverable for the CPS agreement number 15015. The purpose of this project was to develop and commercialize a family of lightweight, bulk composite materials that are highly resistant to degradation by erosive and abrasive wear. These materials, based on AlMgB{sub 14}, are projected to save over 30 TBtu of energy per year when fully implemented in industrial applications, with the associated environmental benefits of eliminating the burning of 1.5 M tons/yr of coal and averting the release of 4.2 M tons/yr of CO{sub 2} into the air. This program targeted applications in the mining, drilling, machining, and dry erosion applications as key platforms for initial commercialization, which includes some of the most severe wear conditions in industry. Production-scale manufacturing of this technology has begun through a start-up company, NewTech Ceramics (NTC). This project included providing technical support to NTC in order to facilitate cost-effective mass production of the wear-resistant boride components. Resolution of issues related to processing scale-up, reduction in energy intensity during processing, and improving the quality and performance of the composites, without adding to the cost of processing were among the primary technical focus areas of this program. Compositional refinements were also investigated in order to achieve the maximum wear resistance. In addition, synthesis of large-scale, single-phase AlMgB{sub 14} powder was conducted for use as PVD sputtering targets for nanocoating applications.

  16. Wear Resistance Assessment of Fluoropolymer Coated Gears

    Directory of Open Access Journals (Sweden)

    Lidia Nedeloni

    2017-11-01

    Full Text Available Power transmissions that incorporate gears dissipate a significant amount of energy and noise. Thus, any improvement in their performance contributes to reducing energy consumption and noise pollution. In recent years, the opportunities offered by conventional technologies to increase gear performance have been fully exploited. Therefore, surface depositions on gear teeth have become increasingly important technologies in achieving objectives such as: improving energy performance, providing greater protection against superficial defects, increasing load capacity and reducing acoustic emissions generated during operation. However, gear coating technologies have begun to be developed, but the investigations are still insufficient. In this study, we carried out wear resistance investigations performed on fluoropolymer coatings for different working speeds, loads and lubrication conditions. The results point out that the deterioration rate of the coating increases with the increase of the working speed and the applied load. In addition, a slight lubrication, applied at the start of testing, leads to a noticeable improvement in wear behaviour. This study represents one step further in understanding the wear process of fluoropolymer coated gears

  17. THE WEAR RESISTANCE INCREASE OF CHROMIUM CAST IRON

    Directory of Open Access Journals (Sweden)

    V. M. Ilyushenko

    2016-01-01

    Full Text Available The article presents the results of the tests on the wear resistance of chromium cast irons of different compositions obtained in sand forms. It has been shown that increase of the wear resistance and mechanical properties of the cast iron is possible to obtain using the casting in metal molds. A further increase in wear resistance of parts produced in metal molds is possible by changing the technological parameters of casting and alloying by titanium.

  18. Aluminum nanocomposites having wear resistance better than stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    An, Linan [University of Central Florida; Qu, Jun [ORNL; Luo, Jinsong [Chinese Academy of Sciences; Fan, Yi [Chinese Academy of Sciences; Zhang, Ligong [University of Central Florida; Liu, Jinling [University of Central Florida; Xu, Chengying [University of Central Florida; Blau, Peter Julian [ORNL

    2011-01-01

    Tribological behavior of alumina-particle-reinforced aluminum composites made by powder metallurgy process has been investigated. The nanocomposite containing 15 vol% of Al2O3 nanoparticles exhibits excellent wear resistance by showing significantly low wear rate and abrasive wear mode. The wear rate of the nanocomposite is even lower than stainless steel. We have also demonstrated that such excellent wear resistance only occurred in the composite reinforced with the high volume fraction of nanosized reinforcing particles. The results were discussed in terms of the microstructure of the nanocomposite.

  19. Correlation between Wear Resistance and Lifetime of Electrical Contacts

    Directory of Open Access Journals (Sweden)

    Jian Song

    2012-01-01

    Full Text Available Electrical contacts are usually plated in order to prevent corrosion. Platings of detachable electrical contacts experience wear because of the motion between contacts. Once the protecting platings have been worn out, electrical contacts will fail rapidly due to corrosion or fretting corrosion. Therefore the wear resistance of the platings is a very important parameter for the long lifetime of electrical contacts. Many measures which improve the wear resistance can diminish the conductivity of the platings. Due to the fact that platings of electrical contacts must have both a high wear resistance and a high electrical conductivity, the manufacturing of high performance platings of electrical contacts poses a great challenge. Our study shows firstly the correlation between the wear resistance of platings and lifetime of electrical contacts and then the measures, which improve the wear resistance without impairing the electrical performance of the contacts.

  20. Titanium aluminide intermetallic alloys with improved wear resistance

    Science.gov (United States)

    Qu, Jun; Lin, Hua-Tay; Blau, Peter J.; Sikka, Vinod K.

    2014-07-08

    The invention is directed to a method for producing a titanium aluminide intermetallic alloy composition having an improved wear resistance, the method comprising heating a titanium aluminide intermetallic alloy material in an oxygen-containing environment at a temperature and for a time sufficient to produce a top oxide layer and underlying oxygen-diffused layer, followed by removal of the top oxide layer such that the oxygen-diffused layer is exposed. The invention is also directed to the resulting oxygen-diffused titanium aluminide intermetallic alloy, as well as mechanical components or devices containing the improved alloy composition.

  1. Effect of Lubricant Contaminants on Wear Rates of Lubricated Components.

    Science.gov (United States)

    1980-11-13

    34 Radiotracers Reveal Engine Wear During Detergent Oil Filtration Study," SAE Trans., Vol. 68, 1960, pp. 288-297. 45. Weber, K. H., "Hydrodynamic Theory of...Paper No. 71-Vibr.-96. 49. Naval Air Engineering Center/SKF Industries , " Oil Analysis Project," A/T A3400000/051B/5F53537401, 21 November 1974. 50...study on the effect of particulate contamination upon the wear rates of oil -vetted components normally used in lubrication systems. The components

  2. 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.

  3. EVALUATION AND RECOMMENDATION OF SALTSTONE MIXER AUGER/PADDLES MATERIALS OF CONSTRUCTION FOR IMPROVED WEAR RESISTANCE

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.; Torres, R.

    2012-08-15

    Wear and corrosion testing were conducted to evaluate alternate materials of construction for the Saltstone mixer auger and paddles. These components have been degraded by wear from the slurry processed in the mixer. Material test options included PVD coatings (TiN, TiCN, and ZrN), weld overlays (Stellite 12 and Ultimet) and higher hardness steels and carbides (D2 and tungsten carbide). The corrosion testing demonstrated that the slurry is not detrimental to the current materials of construction or the new candidates. The ASTM G75 Miller wear test showed that the high hardness materials and the Stellite 12 weld overlay provide superior wear relative to the Astralloy and CF8M stainless steel, which are the current materials of construction, as well as the PVD coatings and Ultimet. The following recommendations are made for selecting new material options and improving the overall wear resistance of the Saltstone mixer components: A Stellite 12 weld overlay or higher hardness steel (with toughness equivalent to Astralloy) be used to improve the wear resistance of the Saltstone mixer paddles; other manufacturing specifications for the mixer need to be considered in this selection. The current use of the Stellite 12 weld overlay be evaluated so that coverage of the 316 auger can be optimized for improved wear resistance of the auger. The wear surfaces of the Saltstone mixer auger and paddles be evaluated so that laboratory data can be better correlated to actual service. The 2-inch Saltstone mixer prototype be used to verify material performance.

  4. Wear of Spheroidal Graphite Cast Irons for Tractor Drive Train Components

    Energy Technology Data Exchange (ETDEWEB)

    Beltowski, Mark F [ORNL; Blau, Peter Julian [ORNL; Qu, Jun [ORNL

    2009-01-01

    The study was prompted by a desire to improve the wear resistance of power transmission components in rear axle drives on commercial farm tractors. Reciprocating wear tests were conducted under lubricated and non-lubricated conditions on three spheroidal cast irons which varied in strength and hardness (designated GGG450, GGG600, and GGG700). Hemispherically-tipped steel pins (designed 42CrMoS4/ 41CrS4) were used as the sliders. Except for the test duration, test procedures were similar to those described in ASTM Standard Test Method G133 for linearly-reciprocating sliding. Among the three cast irons tested, the harder and stronger the alloy, the lower was its wear rate. Wear factors were approximately four orders of magnitude lower for experiments lubricated in fresh, fully-formulated lubricating oil. There was a linear relationship between Brinell hardness of the alloys and the negative logarithm of the wear factors that were expressed in (mm3/N-m). Wear of lubricated test pins was not measurable due to the presence of deposits; however under non-lubricated sliding, the ratio of the wear of the flat specimen to that of the pin decreased as the hardness of the flat specimens approached that of the pin specimen.

  5. WEAR-RESISTANCE OF CHROMIC CAST IRONS OF EUTECTIC COMPOSITION

    Directory of Open Access Journals (Sweden)

    K. E. Baranovskij

    2009-01-01

    Full Text Available Casting of wear-resistant chrome cast irons in combined molds and iron chills is studied. Application of these ways of casting results in blending of carbides and increasing of hardness of castings.

  6. Development of an injection molding technique for the production of lightweight high temperature wear resistant, glassy carbon components for machine and motor construction

    Science.gov (United States)

    Duebgen, Rainer

    1986-12-01

    The efficient and inexpensive manufacture of glassy carbon components using specially developed raw materials was investigated. An unfilled, phenolic resin which can be efficiently and cheaply processed into molds by injection molding was derived. The molds can be converted into glassy carbon in solid phase pyrolysis with a high coke yield and relatively small shrinkage factor. The fracture mechanical values for the material were determined, and combined corrosion strength measurements were carried out. The production process was used in the manufacture of nozzles.

  7. Characterization of the wear resistant aluminum oxide - 40% titaniumdioxide coating

    Directory of Open Access Journals (Sweden)

    Mihailo R. Mrdak

    2014-02-01

    Full Text Available Plasma spray coatings play an important role in the design of surface properties of engineering components in order to increase their durability and performance under different operating conditions. Coatings are the most often used for wear resistance. This paper presents the microstructure and mechanical properties Al2O3_­40wt.%TiO2 coating resistant to dry friction slide, grain abrasion and erosion of particles at operating temperatures up to 540°C. In order to obtain the optimal characteristics of coating was performed  optimization  of deposition parameters. The powder Al2O3­40wt.%TiO2 is deposited atmospheric plasma spraying (APS process with a plasma current of 700, 800 and 900A. Evaluate the quality of the coating Al2O3­40wt.%TiO2 were made on the basis of their hardness, tensile bond strength and microstructure. The best performance showed the deposited layers with 900A. The morphology of the powder particles Al2O3­40wt.%TiO2 was examined with SEM (Scanning Electron Microscope. Microstructure of the coatings was examined by light microscopy. Analysis of the deposited layers was performed in accordance with standard Pratt & Whitney. Evaluation of mechanical properties of the layers was done by examining HV0.3 microhardness and tensile strength of the tensile testing. Studies have shown that plasma currents significantly affects the mechanical properties and microstructure of coatings which are of crucial importance for the protection for components subjected to wear       

  8. Micro-Abrasion Wear Resistance of Borided 316L Stainless Steel and AISI 1018 Steel

    Science.gov (United States)

    Reséndiz-Calderon, C. D.; Rodríguez-Castro, G. A.; Meneses-Amador, A.; Campos-Silva, I. E.; Andraca-Adame, J.; Palomar-Pardavé, M. E.; Gallardo-Hernández, E. A.

    2017-11-01

    The 316L stainless steel has high corrosion resistance but low tribological performance. In different industrial sectors (biomedical, chemical, petrochemical, and nuclear engineering), improvement upon wear resistance of 316L stainless steel components using accessible and inexpensive methods is critical. The AISI 1018 steel is widely used in industry, but its tribological performance is not the best among steels. Therefore, in this study the behavior of the borided 316L stainless steel and 1018 steel is evaluated under micro-abrasion wear. The boriding was carried out at 1223 K over 6 h of exposure time, resulting in a biphase layer composed of FeB/Fe2B phases. In order to evaluate Fe2B phase with no influence from FeB phase, AISI 1018 steel samples were borided at 1273 K for over 20 min and then diffusion annealed at 1273 K over 2 h to obtain a Fe2B mono-phase layer. Micro-abrasion wear resistance was evaluated by a commercial micro-abrasion testing rig using a mix of F-1200 SiC particles with deionized water as abrasive slurry. The obtained wear rates for FeB and Fe2B phases and for the 316L stainless steel were compared. Wear resistance of 316L stainless steel increases after boriding. The wear mechanisms for both phases and for the stainless steel were identified. Also, transient conditions for rolling and grooving abrasion were determined for the FeB and Fe2B phases.

  9. Micro-Abrasion Wear Resistance of Borided 316L Stainless Steel and AISI 1018 Steel

    Science.gov (United States)

    Reséndiz-Calderon, C. D.; Rodríguez-Castro, G. A.; Meneses-Amador, A.; Campos-Silva, I. E.; Andraca-Adame, J.; Palomar-Pardavé, M. E.; Gallardo-Hernández, E. A.

    2017-10-01

    The 316L stainless steel has high corrosion resistance but low tribological performance. In different industrial sectors (biomedical, chemical, petrochemical, and nuclear engineering), improvement upon wear resistance of 316L stainless steel components using accessible and inexpensive methods is critical. The AISI 1018 steel is widely used in industry, but its tribological performance is not the best among steels. Therefore, in this study the behavior of the borided 316L stainless steel and 1018 steel is evaluated under micro-abrasion wear. The boriding was carried out at 1223 K over 6 h of exposure time, resulting in a biphase layer composed of FeB/Fe2B phases. In order to evaluate Fe2B phase with no influence from FeB phase, AISI 1018 steel samples were borided at 1273 K for over 20 min and then diffusion annealed at 1273 K over 2 h to obtain a Fe2B mono-phase layer. Micro-abrasion wear resistance was evaluated by a commercial micro-abrasion testing rig using a mix of F-1200 SiC particles with deionized water as abrasive slurry. The obtained wear rates for FeB and Fe2B phases and for the 316L stainless steel were compared. Wear resistance of 316L stainless steel increases after boriding. The wear mechanisms for both phases and for the stainless steel were identified. Also, transient conditions for rolling and grooving abrasion were determined for the FeB and Fe2B phases.

  10. Evaluation of hardness and wear resistance of interim restorative materials.

    Science.gov (United States)

    Savabi, Omid; Nejatidanesh, Farahnaz; Fathi, Mohamad Hossein; Navabi, Amir Arsalan; Savabi, Ghazal

    2013-03-01

    The interim restorative materials should have certain mechanical properties to withstand in oral cavity. The aim of this study was to evaluate the hardness and wear resistance of interim restorative materials. Fifteen identical rectangular shape specimens with dimensions of 2 mm × 10 mm × 30 mm were made from 7 interim materials (TempSpan, Protemp 3 Garant, Revotek, Unifast LC, Tempron, Duralay, and Acropars). The Vickers hardness and abrasive wear of specimens were tested in dry conditions and after 1 week storage in artificial saliva. The depth of wear was measured using surface roughness inspection device. Data were subjected to Kruskal-Wallis and Mann-Whitney tests. The Pearson correlation coefficient was used to determine the relationship between hardness and wear (α =0.05). TempSpan had the highest hardness. The wear resistance of TempSpan (in dry condition) and Revotek (after conditioning in artificial saliva) was significantly higher (P materials (P = 0.281, r = -0.31). Hardness and wear resistance of interim resins are material related rather than category specified.

  11. Wear resistance of experimental titanium alloys for dental applications.

    Science.gov (United States)

    Faria, Adriana Cláudia Lapria; Rodrigues, Renata Cristina Silveira; Claro, Ana Paula Rosifini Alves; da Gloria Chiarello de Mattos, Maria; Ribeiro, Ricardo Faria

    2011-11-01

    The present study evaluated microstructure, microhardness and wear resistance of experimental titanium alloys containing zirconium and tantalum. Alloys were melted in arc melting furnace according to the following compositions: Ti-5Zr, Ti-5Ta and Ti-5Ta-5Zr (%wt). Hemispheres and disks were obtained from wax patterns that were invested and cast by plasma. Microstructures were evaluated using optical microscopy and X-ray diffraction (XRD) analysis and also Vickers microhardness was measured. Hemispherical samples and disks were used for 2-body wear tests, performed by repeated grinding of the samples. Wear resistance was assessed as height loss after 40,000 cycles. The data were compared using ANOVA and post-hoc Tukey test. Ti-5Zr presented a Widmanstätten structure and the identified phases were α and α' while Ti-5Ta and Ti-5Ta-5Zr presented α, β, α' and α" phases, but the former presented a lamellar structure, and the other, acicular. The microhardness of Ti-5Zr was significantly greater than other materials and cp Ti presented wear resistance significantly lower than experimental alloys. It was concluded that wear resistance was improved when adding Ta and Zr to titanium and Zr increased microhardness of Ti-5Zr alloy. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Improvement of wear-resistance of solid lubricants by ionic impact

    DEFF Research Database (Denmark)

    1993-01-01

    A solid lubricating material, preferentially as a coating, deposited on a substrate surface by conventional technique such as dipping in a suspension, painting, or spraying is bombarded with energetic ions fron an ion accelerator or in a plasma discharge. By such a treatment the wear resistance...... crystalline planes which are parellel to the component surface to be lubricated....

  13. Engineering wear-resistant surfaces in automotive aluminum

    Science.gov (United States)

    Kavorkijan, V.

    2003-02-01

    Inadequate wear resistance and low seizure loads prevent the direct use of aluminum alloys in automotive parts subject to intensive friction combined with high thermal and mechanical loading, such as brake discs, pistons, and cylinder liners. To enable the use of aluminum alloys in the production of automotive brake discs and other wear-resistant products, the insertion of a monolithic friction cladding rather than surface coating has been considered in this work. Three experimental approaches, two based on the pressure-less infiltration of porous ceramic preforms and one based on the subsequent hot rolling of aluminum and metal-matrix composite strips, are currently under investigation.

  14. Fissure sealant materials: Wear resistance of flowable composite resins.

    Science.gov (United States)

    Asefi, Sohrab; Eskandarion, Solmaz; Hamidiaval, Shadi

    2016-01-01

    Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow), Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists). A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm(2) and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm(2)of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics.

  15. Fissure sealant materials: Wear resistance of flowable composite resins

    Directory of Open Access Journals (Sweden)

    Sohrab Asefi

    2016-08-01

    Full Text Available Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow, Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists. A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm2 and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm2of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics.

  16. (AJST) EFFECT OF HEAT TREATMENT ON WEAR RESISTANCE ...

    African Journals Online (AJOL)

    ABSTRACT: The effects of heat treatment on the hardness and by extension the wear resistance of locally produced grinding plate ... from the grinding plate and were heat treated at 840°C, 860°C and 880°C and quenched at different rate. Some of the ... during dry sliding at low loading conditions has been attributed to the ...

  17. On the Durability and Wear Resistance of Transparent Superhydrophobic Coatings

    Directory of Open Access Journals (Sweden)

    Ilker S. Bayer

    2017-01-01

    Full Text Available Transparent liquid repellent coatings with exceptional wear and abrasion resistance are very demanding to fabricate. The most important reason for this is the fact that majority of the transparent liquid repellent coatings have so far been fabricated by nanoparticle assembly on surfaces in the form of films. These films or coatings demonstrate relatively poor substrate adhesion and rubbing induced wear resistance compared to polymer-based transparent hydrophobic coatings. However, recent advances reported in the literature indicate that considerable progress has now been made towards formulating and applying transparent, hydrophobic and even oleophobic coatings onto various substrates which can withstand certain degree of mechanical abrasion. This is considered to be very promising for anti-graffiti coatings or treatments since they require resistance to wear abrasion. Therefore, this review intends to highlight the state-of-the-art on materials and techniques that are used to fabricate wear resistant liquid repellent transparent coatings so that researchers can assess various aptitudes and limitations related to translating some of these technologies to large scale stain repellent outdoor applications.

  18. Evaluation Of Saltstone Mixer Paddle Configuration For Improved Wear Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Reigel, M. M.; Fowley, M. D.; Pickenheim, B. R.

    2012-09-27

    A soft metal with low wear resistance (6000 series aluminum), was used to minimize run time while maximizing wear rate. Two paddle configurations were tested, with the first four paddles after the augers replaced by the wear paddles. The first configuration was all flat paddles, with the first paddle not aligned with the augers and is consistent with present SPF mixer. The second configuration had helical paddles for the first three stages after the augers and a flat paddle at the fourth stage. The first helical paddle was aligned with the auger flight for the second configuration. The all flat paddle configuration wear rate was approximately double the wear rate of the helical paddles for the first two sets of paddles after the augers. For both configurations, there was little or no wear on the third and fourth paddle sets based on mass change, indicating that the fully wetted premix materials are much less abrasive than the un-wetted or partially wetted premix. Additionally, inspection of the wear surface of the paddles at higher magnification showed the flat paddles were worn much more than the helical and is consistent with the wear rates. Aligning the auger discharge flight with the first set of helical paddles was effective in reducing the wear rate as compared to the flat paddle configuration. Changing the paddle configuration from flat to helical resulted in a slight increase in rheological properties. Although, both tests produced grout-like material that is within the processing rage of the SPF, it should be noted that cement is not included in the premix and water was used rather than salt solution, which does affect the rheology of the fresh grout. The higher rheological properties from the helical wear test are most likely due to the reduced number of shearing paddles in the mixer. In addition, there is variation in the rheological data for each wear test. This is most likely due to the way that the dry feeds enter the mixer from the dry feeder. The

  19. Wear resistance of polypropylene-SiC composite

    Science.gov (United States)

    Abenojar, J.; Enciso, B.; Martínez, MA; Velasco, F.

    2017-05-01

    In this work, the wear resistance of thermoplastic composites with a high amount of ceramic is evaluated. Composites made of polypropylene (PP) and silicon carbide (SiC) powder at 50 wt% were used with the final objective of manufacturing ablative materials. This is the first part of a project studying the wear resistance and the mechanical properties of those composites, to be used in applications like habitat industry. In theory, the exposure to high temperature of ablative materials involves the elimination of thermal energy by the sacrifice of surface polymer. In our case, PP will act as a heat sink, up to the reaction temperature (melting or sublimation), where endothermic chemical decomposition into charred material and gaseous products occurs. As the surface is eroded, it is formed a SiC like-foam with improved insulation performance. Composites were produced by extrusion and hot compression. The wear characterization was performed by pin-on-disk test. Wear test was carried out under standard ASTM G99. The parameters were 120 rpm speed, 15 N load, a alumina ball with 6 mm as pin and 1000 m sliding distance. The tracks were also observed by opto-digital microscope.

  20. Study of Stainless Steel Resistance in Conditions of Tribocorrosion Wear

    Directory of Open Access Journals (Sweden)

    Goran Rozing

    2015-07-01

    Full Text Available Analyzed was the influence of tribocorrosion wear due to effects of fatty acids present in the processed medium. The analysis was conducted on samples made of two austenitic and two martensitic stainless steels. Austenitic steels were tested in their nitrided state and martensitic in their induction hardened state. Conducted were laboratory tests of corrosion resistance of samples, analysis of the microstructure and hardness. To see how the applied processes for modifying the surface of stainless steels behave in realistic conditions, it was conducted the examination of samples/parts of a sunflower cake chain conveyer. Based on the comparison of results obtained in the laboratory and in real conditions, it was estimated that steels AISI 420 and AISI 431 with induction hardened surfaces have a satisfactory resistance to abrasive-adhesive wear in the presence of fatty acids.

  1. Progress in Wear Resistant Materials for Total Hip Arthroplasty

    Directory of Open Access Journals (Sweden)

    Rohit Khanna

    2017-07-01

    Full Text Available Current trends in total hip arthroplasty (THA are to develop novel artificial hip joints with high wear resistance and mechanical reliability with a potential to last for at least 25–30 years for both young and old active patients. Currently used artificial hip joints are mainly composed of femoral head of monolithic alumina or alumina-zirconia composites articulating against cross-linked polyethylene liner of acetabular cup or Co-Cr alloy in a self-mated configuration. However, the possibility of fracture of ceramics or its composites, PE wear debris-induced osteolysis, and hypersensitivity issue due to metal ion release cannot be eliminated. In some cases, thin ultra-hard diamond-based, TiN coatings on Ti-6A-4V or thin zirconia layer on the Zr-Nb alloy have been fabricated to develop high wear resistant bearing surfaces. However, these coatings showed poor adhesion in tribological testing. To provide high wear resistance and mechanical reliability to femoral head, a new kind of ceramic/metal artificial hip joint hybrid was recently proposed in which 10–15 μm thick dense layer of pure α-alumina was formed onto Ti-6Al-4V alloy by deposition of Al metal layer by cold spraying or cold metal transfer methods with 1–2 μm thick Al3Ti reaction layer formed at their interface to improve adhesion. An optimal micro-arc oxidation treatment transformed Al to dense α-alumina layer, which showed high Vickers hardness 1900 HV and good adhesion to the substrate. Further tribological and cytotoxicity analyses of these hybrids will determine their efficacy for potential use in THA.

  2. Investigation of Wear Resistant of Low-Alloyed and Chromium Cast Steel

    Directory of Open Access Journals (Sweden)

    A. Studnicki

    2012-04-01

    Full Text Available Results of investigations of wear resistant of two species of cast steel were introduced in the article (low-alloyed and chromium cast steel on the background of the standard material which was low alloy wear resistant steel about the trade name CREUSABRO ®8000. The investigations were executed with two methods: abrasive wears in the stream of loose particles (the stream of quartz sand and abrasive wears particles fixed (abrasive paper with the silicon carbide. Comparing the results of investigations in the experiments was based about the counted wear index which characterizes the wears of the studied material in the relation to the standard material.

  3. Wear Resistance Analysis of A359/SiC/20p Advanced Composite Joints Welded by Friction Stir Welding

    Directory of Open Access Journals (Sweden)

    O. Cuevas Mata

    Full Text Available Abstract Advancement in automotive part development demands new cost-effective materials with higher mechanical properties and improved wear resistance as compared to existing materials. For instance, Aluminum Matrix Composites (AMC shows improved mechanical properties as wear and abrasion resistance, high strength, chemical and dimensional stability. Automotive industry has focused in AMC for a variety of applications in automotive parts in order to improve the fuel economy, minimize vehicle emissions, improve design options, and increase the performance. Wear resistance is one of the most important factors in useful life of the automotive components, overall in those components submitted to mechanical systems like automotive brakes and suspensions. Friction Stir Welding (FSW rises as the most capable process to joining AMC, principally for the capacity to weld without compromising their ceramic reinforcement. The aim of this study is focused on the analysis of wear characteristics of the friction-stir welded joint of aluminum matrix reinforced with 20 percent in weight silicon carbide composite (A359/SiC/20p. The experimental procedure consisted in cut samples into small plates and perform three welds on these with a FSW machine using a tool with 20 mm shoulder diameter and 8 mm pin diameter. The wear features of the three welded joints and parent metal were analyzed at constant load applying 5 N and a rotational speed of 100 rpm employing a Pin-on - Disk wear testing apparatus, using a sapphire steel ball with 6 mm diameter. The experimental results indicate that the three welded joints had low friction coefficient compared with the parent metal. The results determine that the FSW process parameters affect the wear resistance of the welded joints owing to different microstructural modifications during welding that causes a low wear resistance on the welded zone.

  4. The problem of wear-resistant coatings quality

    Directory of Open Access Journals (Sweden)

    Mi. I. Abashin

    2014-01-01

    Full Text Available The article aims at solving a problem concerning the express evaluation of the wear-resistant nanostructure coatings quality using the method of ultra-fluid jet examination. Conducted research activities have shown that an intensity of the coating delamination from the substrate depends on the stress concentration level in the test sample. The proposed informatively methodological procedure of ultra-fluid jet examination will allow prompt estimation of physical-and-mechanical parameters and operational condition of coatings being deposited on samples and passed fatigue loading. The offered procedure can be effectively used for selecting the coating material, substrate, and efficient modes of application.

  5. Standard Test Method for Abrasive Wear Resistance of Cemented

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the determination of abrasive wear resistance of cemented carbides. 1.2 The values stated in inch-pound units are to be regarded as the standard. The SI equivalents of inch-pound units are in parentheses and may be approximate. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  6. Tantalum-based thin film coatings for wear resistant arthroprostheses.

    Science.gov (United States)

    Balagna, C; Faga, M G; Spriano, S

    2011-10-01

    Cobalt-chromium-molybdenum alloys with high carbon content (HC-CoCrMo) are widely used as materials for arthroprosthesis, in particular in metal-on-metal (MoM) hip joints. In spite of their good wear and corrosion resistance, production of metallic wear particles and metal ion release will occur on a large time-scale. An enhancement of the metal ion level in the patient's blood and urine is often reported in clinical data. Hypersensitivity, inflammatory response and cell necrosis can occur as consequence. So implants on young patients and women on childbearing age are not so widespread. The aim of this research is the realization of a thin film coating in order to improve the biocompatibility of Co-based alloys and to reduce debris production, ion release and citotoxicity. The innovative process consists of a thermal treatment in molten salts, in order to obtain a tantalum enriched thin film coating. Tantalum is chosen because it is considered a biocompatible metal with high corrosion resistance and low ion release. Three HC-CoCrMo alloys, produced by different manufacturing processes, are tested as substrates. The coating is a thin film of TaC or it can be composed by a multilayer of two tantalum carbides and metallic tantalum, depending on the temperature of the treatment and on the carbon content of the substrate. The thin films as well the substrates are characterized from the structural, chemical and morphological point of view. Moreover mechanical behaviour of treated and untreated materials is analyzed by means of nanohardness, scratch and ball-on-disc wear tests. The coating increases the mechanical and tribological properties of HC-CoCrMo.

  7. Study on Composition, Microstructure and Wear Behavior of Fe-B-C Wear-Resistant Surfacing Alloys

    Science.gov (United States)

    Zhuang, Minghui; Li, Muqin; Wang, Jun; Ma, Zhen; Yuan, Shidan

    2017-11-01

    Fe-B-C alloy layers with various microstructures were welded on Q235 steel plates using welding powders/H08Mn2Si and welding wires composite surfacing technology. The relationship existing between the chemical composition, microstructure and wear resistance of the surfacing alloy layers was investigated by scanning electron microscopy, x-ray diffraction, electron backscatter diffraction and wear tests. The results demonstrated that the volume fractions and morphologies of the microstructures in the surfacing alloy layers could be controlled by adjusting the boron and carbon contents in the welding powders, which could further regulate the wear resistance of the surfacing alloy layers. The typical microstructures of the Fe-B-C surfacing alloy layers included dendritic Fe, rod-like Fe2B, fishbone-like Fe2B and daisy-like Fe3(C, B). The wear resistance of the alloy layers with various morphologies differed. The wear resistance order of the different microstructures was: rod-like Fe2B > fishbone-like Fe2B > daisy-like Fe3(C, B) > dendritic Fe. A large number of rod-like Fe2B with high microhardness could be obtained at the boron content of 5.70 5.90 wt.% and the carbon content of 0.50 0.60wt.%. The highest wear resistance of the Fe-B-C alloy layers reached the value of 24.1 g-1, which demonstrates the main microscopic cutting wear mechanism of the Fe-B-C alloy layers.

  8. Effect of bionic coupling units' forms on wear resistance of gray cast iron under dry linear reciprocating sliding condition

    Science.gov (United States)

    Pang, Zuobo; Zhou, Hong; Xie, Guofeng; Cong, Dalong; Meng, Chao; Ren, Luquan

    2015-07-01

    In order to get close to the wear form of guide rails, the homemade linear reciprocating wear testing machine was used for the wear test. In order to improve the wear-resistance of gray cast iron guide rail, bionic coupling units of different forms were manufactured by a laser. Wear behavior of gray-cast-iron with bionic-coupling units has been studied under dry sliding condition at room temperature using the wear testing machine. The wear resistance was evaluated by means of weight loss measurement and wear morphology. The results indicated that bionic coupling unit could improve the wear resistance of gray cast iron. The wear resistance of gray cast iron with reticulation bionic coupling unit is the best. When the load and speed changed, reticulation bionic coupling unit still has excellent performance in improving the wear resistance of gray cast iron.

  9. High Thermal Conductivity and High Wear Resistance Tool Steels for cost-effective Hot Stamping Tools

    Science.gov (United States)

    Valls, I.; Hamasaiid, A.; Padré, A.

    2017-09-01

    In hot stamping/press hardening, in addition to its shaping function, the tool controls the cycle time, the quality of the stamped components through determining the cooling rate of the stamped blank, the production costs and the feasibility frontier for stamping a given component. During the stamping, heat is extracted from the stamped blank and transported through the tool to the cooling medium in the cooling lines. Hence, the tools’ thermal properties determine the cooling rate of the blank, the heat transport mechanism, stamping times and temperature distribution. The tool’s surface resistance to adhesive and abrasive wear is also an important cost factor, as it determines the tool durability and maintenance costs. Wear is influenced by many tool material parameters, such as the microstructure, composition, hardness level and distribution of strengthening phases, as well as the tool’s working temperature. A decade ago, Rovalma developed a hot work tool steel for hot stamping that features a thermal conductivity of more than double that of any conventional hot work tool steel. Since that time, many complimentary grades have been developed in order to provide tailored material solutions as a function of the production volume, degree of blank cooling and wear resistance requirements, tool geometries, tool manufacturing method, type and thickness of the blank material, etc. Recently, Rovalma has developed a new generation of high thermal conductivity, high wear resistance tool steel grades that enable the manufacture of cost effective tools for hot stamping to increase process productivity and reduce tool manufacturing costs and lead times. Both of these novel grades feature high wear resistance and high thermal conductivity to enhance tool durability and cut cycle times in the production process of hot stamped components. Furthermore, one of these new grades reduces tool manufacturing costs through low tool material cost and hardening through readily

  10. Improvement of wear resistance for C45 steel using plasma nitriding, nitrocarburizing and nitriding/ manganese phosphating duplex treatment

    Science.gov (United States)

    Doan, T. V.; Kusmič, D.; Pospíchal, M.; Dobrocký, D.

    2017-02-01

    This article focuses on effect of plasma nitriding, nitrocarburizing and nitriding/manganese phosphating duplex treatments to wear resistance of C45 steel substrate. The wear test “ball on disc” was conducted to evaluate the coefficient of friction and wear rate using the BRUKER UMT-3 tribometer. The analysis results indicated that nitrocarburizing obtained the best wear resistance; the worst wear resistance was plasma nitriding. Manganese phosphating coating enabled to reduce the coefficient of friction enhanced wear resistance nitrided layer. The used surface treatments also improve non-equal wear of tempered surface over the sliding track.

  11. Comparison of two rocket sled slipper materials for resistance to wear

    Science.gov (United States)

    Liu, Jun; Wang, Weihua; Zhao, Feng; Gong, Mingsheng

    2017-10-01

    The wear loss amount directly affects rocket sled's working speed and safety. The paper evaluates the wear resistance of two materials, 0Cr18Ni9Ti and T250. Wear loss under different working conditions are tested using pin-on-disk experiment for both materials, and an equivalent conversion method to evaluate the slipper wear loss in lab experiment was established. Results show that T250 possesses better wear resistance property than 0Cr18Ni9Ti especially in high pressure and velocity. Above Pv value of 8×107Pa.m/s, the wear loss of 0Cr18Ni9Ti increases exponentially, comparing with a steady wear amount of approximately 0.5g for that of T250. The results provide a reliable reference for the choice of rocket sled slipper material in different range of speed and load.

  12. Plasma powder coating of rods of hydraulic cylinders with white wear resistance cast iron

    Directory of Open Access Journals (Sweden)

    S. P. Nefedyev

    2014-01-01

    Full Text Available The article considers the features to form a structure and properties of Fe-C-Cr-V system coverings provided by the plasma and powder coating (build-up on the low carbon steel.It is shown that it is possible to restore a rod of hydraulic cylinders of small diameter by the plasma and powder coating. Thus, to avoid buckling and provide the built-up metal structure with the best wear resistance it is necessary to find a reasonable approach to a choice of the operation conditions to provide coating.The paper offers a way for efficient control of heat input at coating and a superheat value of the welding bath. It is noted that the coverings, which have been built up at the smallest heat input in a substrate, possess the best wear resistance, with a fusion zone formed with an austenitic crystallization interlayer.The paper defines consistent patterns to form a structure of coverings under various operation conditions of a plasma and powder coating. It shows the influence of the cooling speed after built-up metal crystallization on the formation of covering structure components.The paper formulates requirements for operation conditions of plasma and powder coating to provide coverings to be subjected to shock and abrasive wear, and shows the influence of additional heat treatment on formation of structure and properties of the built-up metal.The article under review meets available lacks in studying high-carbon chrome-vanadium coverings and is useful for scientists, graduates, and students investigating the wear resistance coating materials and effective methods for their deposition.

  13. Influence of Cycle Temperature on the Wear Resistance of Vermicular Iron Derivatized with Bionic Surfaces

    Science.gov (United States)

    Sui, Qi; Zhang, Peng; Zhou, Hong; Liu, Yan; Ren, Luquan

    2016-11-01

    Depending on their applications, such as in brake discs, camshafts, etc., the wear behavior of vermicular iron is influenced by the thermal cycling regime. The failure of a working part during its service life is a consequence of both thermal fatigue and wear. Previously, the wear and thermal fatigue resistance properties of vermicular iron were separately investigated by researchers, rather than a study combining these two factors. In the present work, the effect of cycle temperature on the wear resistance of specimens with bionic units processed by laser has been investigated experimentally. The wear behavior pre- and post-thermal cycling has also been investigated, and the influence of different cycle temperatures on the wear resistance is discussed. The results indicate that the thermal cycling regime brought about negative influences with varying degrees, on the material properties, such as the microstructures, micro-hardness, cracks, and oxidation resistance properties. All these factors synergistically reduced the wear resistance of vermicular iron. In particular, the negative influence apparently increased with an increase in cycle temperature. Nevertheless, the post-thermal-cycle wear resistance of the specimens with bionic units was superior to those without bionic units. Hence, the laser bionic process is an effective way to improve the performance of vermicular iron in combined thermal cycling and wear service conditions.

  14. Standard test method for ranking resistance of plastics to sliding wear using block-on-ring wear test—cumulative wear method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This test method covers laboratory procedures for determining the resistance of plastics to sliding wear. The test utilizes a block-on-ring friction and wear testing machine to rank plastics according to their sliding wear characteristics against metals or other solids. 1.2 An important attribute of this test is that it is very flexible. Any material that can be fabricated into, or applied to, blocks and rings can be tested. Thus, the potential materials combinations are endless. In addition, the test can be run with different gaseous atmospheres and elevated temperatures, as desired, to simulate service conditions. 1.3 Wear test results are reported as the volume loss in cubic millimetres for the block and ring. Materials of higher wear resistance will have lower volume loss. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with it...

  15. Improvement of Wear Resistance in Alumina Matrix Composites Reinforced with Carbon Nanotubes

    Science.gov (United States)

    Kim, Sung Wan; Chung, Won Sub; Sohn, Kee-Sun; Son, Chang-Young; Lee, Sunghak

    2010-02-01

    Alumina matrix composites reinforced with carbon nanotubes (CNTs) fabricated by CNT purification, mixing, compaction, and sintering processes, and the effects of the CNT addition on wear resistance were investigated in relation to the relative density, hardness, and fracture toughness. Wear resistance and fracture toughness were measured by the dry sliding wear test method and the indentation fracture test method, respectively. Zero to ~3 vol pct of CNTs were homogeneously distributed in the composites, although some pores existed. The wear resistance and fracture toughness increased with an increasing CNT fraction, but the composite specimen containing 3.0 vol pct of CNTs hardly showed an increase over the specimen containing 2.25 vol pct of CNTs. Observations of worn surfaces revealed that the wear mechanism involved both the abrasive and delamination wear modes in the specimens containing 0 to ~0.75 vol pct of CNTs, whereas the surface was worn largely in an abrasive wear mode in the specimens containing 1.5 to ~3.0 vol pct of CNTs. This was because CNTs helped to change the delamination wear mode to the abrasive wear mode by preventing crack initiation and propagation at alumina grains. The fracture toughness increase provided beneficial effects in the resistance to crack initiation and propagation, the reduction in delamination wear on the worn surface, and the consequent improvement in wear resistance. Because the effect of the porosity increase due to the CNT addition unfavorably affected the improvement of wear resistance and fracture toughness in the specimen containing 3.0 vol pct of CNTs, the appropriate level of CNT fraction was 1.5 to ~2.25 vol pct.

  16. Use of microhardness as a simple means of estimating relative wear resistance of carbide thermal spray coatings: Part 2. wear resistance of cemented carbide coatings

    Science.gov (United States)

    Factor, Michael; Roman, Itzhak

    2002-12-01

    A selection of WC-Co and Cr3C2-25%NiCr coatings produced by plasma spray and high velocity oxygen fuel (HVOF) deposition techniques were subjected to various wear tests designed to simulate abrasion, cavitation, sliding, and particle erosion type wear mechanisms. All of the coatings were at least 200 µm thick and were deposited onto stainless steel substrates. In Part 1 of this contribution, the microstructures of the coatings were characterized and their mechanical properties were assessed using microindentation procedures. In this second part of the article, the behavior of the coatings when subjected to the various wear tests is reported and the utility of microhardness testing as an indication of relative wear resistance is discussed. It is shown that correctly performed, appropriate microhardness measurements are a good indication of abrasion resistance and sliding wear resistance, and also correlate well with cavitation resistance in Cr3C2-NiCr. The measurements were less useful for predicting erosion resistance for both Cr3C2-NiCr and WC-Co, however, and for abrasion resistance when WC-Co was ground against SiC. Here the contribution of micromechanisms involving fracturing and brittle failure is greater than that indicated by the coating microhardness, which is essentially a measurement of resistance to plastic deformation under equilibrium conditions.

  17. Effects of sintering temperatures on microstructure and wear resistance of iron-silica composite

    Science.gov (United States)

    Amir, Adibah; Mamat, Othman

    2015-07-01

    Ceramic particle reinforced into metal base matrix composite has been reported to produce higher strength and wear resistance than its alloys because the ceramic phases can strongly resist abrasion. In this study the iron matrix was reinforced with two compositions of 20 and 25 wt. % fine silica particles. The compacts were produced by using powder metallurgy fabrication technique and sintered at three sintering temperatures: 1000, 1100 and 1200°C. Effects of various sintering temperatures on microstructures and the composite's wear resistance were evaluated via optical and SEM microscopy. Both compositions were also subjected to ball-on-disk wear test. The results showed the reinforcement weight fraction of 20 wt.% of silica and sintering temperature at 1100°C exhibited better result, in all aspects. It possessed higher mechanical properties, it's microstructure revealed most intact reinforcing region and it displayed higher wear resistance during wear test.

  18. Influence on the wear resistance of the particle size used in coatings of Alumina

    Science.gov (United States)

    Santos, A.; Guzmán, R.; Ramirez, Z. Y.

    2017-01-01

    In the literature, it is common to find that the size of the particles used in coatings through thermal spraying processes influences the hardness and wear resistance thereof; this project aimed to quantify the importance of this parameter in the adhesive and abrasive wear resistance when aluminium oxide is deposited on a substrate of AISI 1020 steel, through a thermal spraying by flame process. The methodology consisted of: a) morphological characterization of the powder used in the coatings by scanning electron microscopy, b) deposition of coatings, c) testing of adhesive and abrasive wear (ASTM G99-05 Standard test method for wear testing with a pin-on-disk apparatus and ASTM G65-04 Standard test method for measuring abrasion using dry sand/rubber wheel apparatus), and d) statistical analysis to determine the influence of particle size on wear resistance. The average size of the powder used for coatings was 92, 1690, 8990 and 76790nm. The obtained results allow to identify an inversely proportional behaviour between particle size and wear resistance, in both types of wear (adhesive and abrasive) is shown a logarithmic trend indicating an increase in loss mass during the test as the particle size is also increased and therefore a decrease in wear resistance of the coating.

  19. A review of the use of wear-resistant coatings in the cutting-tool industry

    Science.gov (United States)

    Salik, J.

    1983-01-01

    The main mechanisms involved in the wear of cutting tools are reviewed. Evaluation of the different coating properties required for the reduction of the different kinds of wear was also reviewed. The types of coatings and their ranges of applicability are presented and discussed in view of their properties. Various coating processes as well as their advantages and shortcomings are described. Potential future developments in the field of wear-resistant coatings are discussed.

  20. High Density Infrared (HDI) Transient Liquid Coatings for Improved Wear and Corrosion Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Ronald W. Smith

    2007-07-05

    This report documents a collaborative effort between Oak Ridge National Laboratory (ORNL), Materials Resources International and an industry team of participants to develop, evaluate and understand how high density infrared heating technology could be used to improve infiltrated carbide wear coatings and/or to densify sprayed coatings. The research included HDI fusion evaluations of infiltrated carbide suspensions such (BrazeCoat® S), composite suspensions with tool steel powders, thermally sprayed Ni-Cr- B-Si (self fluxing alloy) and nickel powder layers. The applied work developed practical HDI / transient liquid coating (TLC) procedures on test plates that demonstrated the ability to fuse carbide coatings for industrial applications such as agricultural blades, construction and mining vehicles. Fundamental studies helped create process models that led to improved process understanding and control. The coating of agricultural blades was demonstrated and showed the HDI process to have the ability to fuse industrial scale components. Sliding and brasive wear tests showed that high degree of wear resistance could be achieved with the addition of tool steel powders to carbide particulate composites.

  1. Resistance to wear of four matrices with ball attachments for implant overdentures: a fatigue study.

    Science.gov (United States)

    Branchi, Roberto; Vangi, Dario; Virga, Antonio; Guertin, Genevieve; Fazi, Giovanni

    2010-12-01

    The study evaluated in vitro the retention force and the wear resistance over simulated function of four matrix components of ball attachments for implant-retained overdentures. Four types of matrices for ball attachments were evaluated in a fatigue study simulating 5500 cycles of insertion and removal. The matrices used were (1) a Teflon matrix supported by a metal housing, (2) a titanium matrix, (3) a gold alloy matrix, (4) an O-ring matrix using the red color ring for medium retention. Dimensional changes of the ball attachments were investigated with a profilometer. The Teflon matrices showed an increase of 27% in retention at 5500 cycles while the gold alloy matrices showed an increase of 50% in retention in the first 500 cycles and remained relatively stable up to 5500 cycles. On the other hand, titanium matrices and O-ring matrices exhibited progressive loss of retention ending with 68% and 75% of retention loss, respectively, at 5500 cycles. Dimensional analysis by profilometer revealed significant wear on the ball attachment only for titanium matrixes. Gold alloy and Teflon matrices showed the highest retention values without retention loss after 3 years of simulated function. Titanium and O-ring matrices presented a continuous loss of retention with the highest wear on the ball attachments when combined with the titanium matrix. © 2010 by The American College of Prosthodontists.

  2. Influence of Titanium on Crystallization and Wear Resistance of High Chromium Cast Iron

    Directory of Open Access Journals (Sweden)

    Studnicki A.

    2016-03-01

    Full Text Available Paper presents the results of studies on primary crystallization and wear resistance of high chromium cast iron inoculated with ferrotitanium intended for work in abrasive conditions. Primary crystallization was examined with use of TDA method, wear tests of the samples were conducted using the modified pin-on-disk method.

  3. Influence of Titanium on Crystallization and Wear Resistance of High Chromium Cast Iron

    OpenAIRE

    Studnicki A.; Dojka R.; Gromczyk M.; Kondracki M.

    2016-01-01

    Paper presents the results of studies on primary crystallization and wear resistance of high chromium cast iron inoculated with ferrotitanium intended for work in abrasive conditions. Primary crystallization was examined with use of TDA method, wear tests of the samples were conducted using the modified pin-on-disk method.

  4. Is there evidence for accelerated polyethylene wear in uncemented compared to cemented acetabular components? A systematic review of the literature

    NARCIS (Netherlands)

    van der Veen, Hugo; van Jonbergen, H.P.W.; Poolman, R.W.; Bulstra, S.K.; van Raay, J.J.A.M.

    Joint arthroplasty registries show an increased rate of aseptic loosening in uncemented acetabular components as compared to cemented acetabular components. Since loosening is associated with particulate wear debris, we postulated that uncemented acetabular components demonstrate a higher

  5. Effect of the microhardness difference between base metal and bionic coupling unit on wear resistance of gray cast iron

    Science.gov (United States)

    Pang, Zuobo; Zhou, Hong; Chang, Fang; Zhang, Peng; Cong, Dalong; Meng, Chao; Wang, Chuanwei; Ren, Luquan

    2015-12-01

    In order to improve the wear resistance of gray cast iron guide rail, the samples with different microhardness difference between bionic coupling units and base metal were manufactured by laser surface remelting. Wear behavior of gray cast iron with bionic coupling units has been studied under dry sliding condition at room temperature using a homemade liner reciprocating wear testing machine. The wear resistance was evaluated by means of weight loss measurement and wear morphology. The results indicated that when the microhardness difference is 561 HV0.2, the wear resistance of sample is the best.

  6. Lubricated wear resistance of Al-Cu-Mn-Mg-Si and Al-Si-Cu-Mn-Mg alloys against JIS ADC12 aluminium diecast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T. [Junior Coll., Hikone, Shiga (Japan)

    1995-03-01

    Aluminium alloys are light, easy to shape by plastic working, and in the case of casting alloys, can give better products and higher productivity by diecasting. Accordingly, the demand for mechanical components made from aluminium alloys has increased. In addition to strength, wear resistance is often required since moving aluminium components that make sliding contact with each other are becoming more common as machinery becomes lighter. For such applications the wear resistance of aluminium alloys is not generally sufficient unless greatly improved by the use of a lubricant. Thus, designs in which aluminium alloy components slide against one another can be used when the contact conditions are appropriate. (orig.)

  7. Comparison of Wear Resistance of Hawley and Vacuum Formed Retainers: An in-vitro Study

    Directory of Open Access Journals (Sweden)

    Moshkelgosha V

    2016-06-01

    Full Text Available Statement of Problem: As a physical property, wear resistance of the materials used in the fabrication of orthodontic retainers play a significant role in the stability and long term use of the appliances. Objectives: To evaluate the wear resistance of two commonly used materials for orthodontic retainers: Acropars OP, i.e. a polymethyl methacrylate based material, and 3A-GS060, i.e. a polyethylene based material. Materials and Methods: For each material, 30 orthodontic retainers were made according to the manufacturers’ instructions and a 30×30×2 mm block was cut out from the mid- palatal area of each retainer. Each specimen underwent 1000 cycles of wear stimulation in a pin on disc machine. The depth of wear of each specimen was measured using a Nano Wizard II atomic force microscope in 3 random points of each specimen’s wear trough. The average of these three measurements was calculated and considered as mean value wear depth of each specimen (µm. Results: The mean wear depth was 6.10µm and 2.15µm for 3A-GS060 and Acropars OP groups respectively. Independent t-test showed a significant difference between the two groups (p < 0.001. The results show Polymethyl methacrylate base (Acropars is more wear resistance than the polyethylene based material (3A-GS060. Conclusions: As the higher wear resistance of the fabrication material can improve the retainers’ survival time and its cost-effectiveness, VFRs should be avoided in situations that the appliance needs high wear resistance such as bite blocks opposing occlusal forces.

  8. Effect of molybdenum on the microstructure and wear resistance of Fe-based hardfacing coatings

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.H. [School of Materials Science and Engineering, Shandong University, Jinan 250061 (China)], E-mail: xinhongwang@sdu.edu.cn; Han, F. [Department of Mechanical and Electrical Engineering, College of Weifang, Weifang 261021 (China); Liu, X.M.; Qu, S.Y.; Zou, Z.D. [School of Materials Science and Engineering, Shandong University, Jinan 250061 (China)

    2008-08-20

    Fe-based hardfacing alloys containing molybdenum compound have been deposited on AISI 1020 steel substrates by shield manual arc welding (SMAW) process. The effect of Mo on the microstructure and wear resistance of the Fe-based hardfacing alloys were investigated by means of X-ray diffraction, optical microscopy, scanning electron microscopy (SEM) and electron probe microanalysis, as well as wear test. The results indicated that cuboidal and rod-type complex carbides were synthesized in the lath martensite matrix. The fraction of carbides in hardfacing layer increased with an increasing of Mo content. The hardfacing layer with good cracking resistance and wear resistance could be obtained when the amounts of Fe-Mo was controlled within a range of 3-4 wt.%. The improvement of hardness and wear resistance of the hardfacing layers attributed to the formation of Mo{sub 2}C carbide and the solution strengthening of Mo.

  9. Technology for improving the wear resistance of aggregates by materials impregnation

    Science.gov (United States)

    1981-08-01

    The use of impregnation as a means of improving the wear resistance of natural aggregates was investigated. A series of tests were conducted using four aggregates of varying quality, selected from a sampling of 40 different aggregates. Tests performe...

  10. Standard test method for ranking resistance of materials to sliding wear using block-on-ring wear test

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers laboratory procedures for determining the resistance of materials to sliding wear. The test utilizes a block-on-ring friction and wear testing machine to rank pairs of materials according to their sliding wear characteristics under various conditions. 1.2 An important attribute of this test is that it is very flexible. Any material that can be fabricated into, or applied to, blocks and rings can be tested. Thus, the potential materials combinations are endless. However, the interlaboratory testing has been limited to metals. In addition, the test can be run with various lubricants, liquids, or gaseous atmospheres, as desired, to simulate service conditions. Rotational speed and load can also be varied to better correspond to service requirements. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. Wear test results are reported as the volume loss in cubic millimetres for both the block and ring. Materials...

  11. Corrosion and wear resistant metallic layers produced by electrochemical methods

    DEFF Research Database (Denmark)

    Christoffersen, Lasse; Maahn, Ernst Emanuel

    1999-01-01

    Corrosion and wear-corrosion properties of novel nickel alloy coatings with promising production characteristics have been compared with conventional bulk materials and hard platings. Corrosion properties in neutral and acidic environments have been investigated with electrochemical methods...

  12. Deposition of Coatings for Raising the Wear Resistance of Friction Surfaces of Spherical Sliding Bearings

    Science.gov (United States)

    Gorlenko, A. O.; Davydov, S. V.

    2018-01-01

    The process of finishing plasma hardening with deposition of a multilayer amorphous coating of the Si - O - C - N system is considered as applied to hardening of the friction surfaces of spherical sliding bearings. The microrelief, the submicrorelief, and the tribological characteristics of the deposited wear-resistant antifriction amorphous coating, which are responsible for the elevated wear resistance of spherical sliding bearings, are investigated.

  13. Effect of Isothermal Bainitic Quenching on Rail Steel Impact Strength and Wear Resistance

    Science.gov (United States)

    Çakir, Fatih Hayati; Çelik, Osman Nuri

    2017-09-01

    The effect of heat treatment regimes on hardness, impact strength, and wear resistance of rail steel for high-speed tracks (rail quality category R350HT) is studied. Analysis of steel properties with a different structure is compared: pearlitic, and upper and lower bainite. It is shown that the steel with bainitic structure has the best impact strength, but wear resistance is better for steel with a lower bainite structure.

  14. The analysis of mechanism of rhenium-coated tools' wear-resistance rising

    Directory of Open Access Journals (Sweden)

    Daniel Petrosyan

    2017-06-01

    Full Text Available It is proposed to obtain wear-resistant layers on the hard-alloy materials by thermochemical treatment. In the different field of production – mechanical engineering, metallurgy and military technologies, with machine parts demanding high wearproof and corrosion-proof machinery parts on the surfaces of syntheses of diamonds, with metal surface thermal-diffusion with rhenium, to receive diffusion wearing layers for the first time. A method for thermochemical treatment of hard alloy plates has been investigated, allowing to raise the wear-resistance of cutting and mining tools.

  15. Wear resistance of four types of vacuum-formed retainer materials: a laboratory study.

    Science.gov (United States)

    Raja, Taiyub A; Littlewood, Simon J; Munyombwe, Theresa; Bubb, Nigel L

    2014-07-01

    To investigate the resistance to wear of four different vacuum-formed retainer (VFR) materials: Essix C+, Essix ACE, Duran, and Tru-Tain. Essix C+ is a polypropylene polymer; the other materials are polyethylene co-polymers. The study was undertaken at the Leeds Dental Institute, Leeds, UK, with 26 samples in each group. The specimens were vacuum-formed according to the manufacturers' guidelines, and a custom-made wear-simulation machine was used to conduct the test. Each specimen was subjected to 1000 cycles of the wear simulation, with steatite balls as the antagonist material. The resistance to wear of the VFR materials was evaluated by measuring the maximum wear depth using noncontact, three-dimensional surface profilometry. The wear depth was given in micrometers. The median wear depth was 63.20 µm for the Essix C+ group, 7.88 µm for the Essix ACE group, 9.75 µm for the Duran group, and 12.08 µm for the Tru-Tain group. The Kruskal-Wallis test to compare the four VFR materials detected a statistically significant difference between the groups (P materials-Essix ACE, Duran, and Tru-Tain-exhibited significantly less wear than the polypropylene material, Essix C+.

  16. Effect of Anode Pulse-Width on the Microstructure and Wear Resistance of Microarc Oxidation Coatings

    Directory of Open Access Journals (Sweden)

    Zhen-Wei Li

    2017-06-01

    Full Text Available Microarc oxidation (MAO coatings were prepared on 2024-T4 aluminum alloys using a pulsed bipolar power supply at different anode pulse-widths. After the MAO coatings were formed, the micropores and microcracks on the surface of the MAO coatings were filled with Fluorinated ethylene propylene (FEP dispersion for preparing MAO self-lubricating composite coatings containing FEP. The effect of the anode pulse-width on the microstructure and wear resistance of the microarc oxidation coatings was investigated. The wear resistance of the microarc oxidation self-lubricating composite coatings was analyzed. The results revealed that the MAO self-lubricating composite coatings integrated the advantages of wear resistance of the MAO ceramic coatings and a low friction coefficient of FEP. Compared to the MAO coatings, the microarc oxidation self-lubricating composite coatings exhibited a lower friction coefficient and lower wear rates.

  17. Wear resistance of machine tools' bionic linear rolling guides by laser cladding

    Science.gov (United States)

    Wang, Yiqiang; Liu, Botao; Guo, Zhengcai

    2017-06-01

    In order to improve the rolling wear resistance (RWR) of linear rolling guides (LRG) as well as prolong the life of machine tools, various shape samples with different units spaces ranged from 1 to 5 mm are designed through the observation of animals in the desert and manufactured by laser cladding. Wear resistance tests reproducing closely the real operational condition are conducted by using a homemade linear reciprocating wear test machine, and wear resistance is evaluated by means of weight loss measurement. Results indicate that the samples with bionic units have better RWR than the untreated one, of which the reticulate treated sample with unit space 3 mm present the best RWR. More specifically, among the punctuate treated samples, the mass loss increases with the increase of unit space; among the striate treated samples, the mass loss changes slightly with the increase of unit space, attaining a minimum at the unit space of 4 mm; among the reticulate treated samples, with the increase of unit space, the mass loss initially decreases, but turns to increase after reaching a minimum at the unit space of 3 mm. Additionally, the samples with striate shape perform better wear resistance than the other shape groups on the whole. From the ratio value of laser treated area to contacted area perspective, that the samples with ratio value between 0.15 and 0.3 possess better wear resistance is concluded.

  18. Amorphous Metallic Alloys: Pathways for Enhanced Wear and Corrosion Resistance

    Science.gov (United States)

    Aditya, Ayyagari; Felix Wu, H.; Arora, Harpreet; Mukherjee, Sundeep

    2017-11-01

    Amorphous metallic alloys are widely used in bulk form and as coatings for their desirable corrosion and wear behavior. Nevertheless, the effects of heat treatment and thermal cycling on these surface properties are not well understood. In this study, the corrosion and wear behavior of two Zr-based bulk metallic glasses were evaluated in as-cast and thermally relaxed states. Significant improvement in wear rate, friction coefficient, and corrosion penetration rate was seen for both alloys after thermal relaxation. A fully amorphous structure was retained with thermal relaxation below the glass transition. There was an increase in surface hardness and elastic modulus for both alloys after relaxation. The improvement in surface properties was explained based on annihilation of free volume.

  19. Evaluation of Wear Resistance of Friction Materials Prepared by Granulation.

    Science.gov (United States)

    Ma, Yunhai; Liu, Yucheng; Menon, Carlo; Tong, Jin

    2015-10-21

    The tribological properties of friction materials prepared by hot-pressing pellets of different sizes were experimentally investigated. Friction and wear tests of the specimens were performed and morphological analysis was carried out by investigating images acquired with both scanning electron and confocal laser microscopes. The highest friction coefficient of friction materials was obtained with pellets having 1-5 mm size. The lowest wear rate was obtained with pellets having 8-10 mm size. Specimens processed by mixing pellets of different sizes had the highest density and the lowest roughness and were the least expensive to fabricate. The results show that granulation generally enabled increasing the friction coefficient, decreasing the wear rate, and reducing the number of defects on the surface of friction materials.

  20. Evaluation of the wear resistance of new nanocomposite resin restorative materials.

    Science.gov (United States)

    Yesil, Zeynep Duymus; Alapati, Satish; Johnston, William; Seghi, Robert R

    2008-06-01

    The use of composite resins for the restoration of posterior teeth is popular because of the improved performance and appearance of these materials. Wear resistance continues to be of particular importance when restoring large occlusal areas in posterior teeth. The purpose of this study was to evaluate the relative wear characteristics of 2 recently introduced nanofiller-based composite resins (Filtek Supreme, Premise) and compare them to the more traditional microhybrid (Point 4) and microfill (Heliomolar RO) materials that have been used for many years. Six specimens (2 mm thick and 15 mm in diameter) of each material were subjected to 3-body wear tests using the Oregon Health Sciences University Oral Wear Simulator to produce abrasive wear and attrition for all specimens using human enamel as the opposing cusp. Profilometric tracings of the worn surfaces were used to determine the relative abrasive wear, attrition wear, and roughness (Ra) of the composite resin substrate. The mean diameter of the antagonist enamel wear facets was determined under a measuring microscope. Qualitative SEM analysis was also used to assess the surface appearance of the resulting enamel and composite resin wear facets. The data were analyzed by 1-way ANOVA and Tukey's multiple range post hoc test (alpha=.05). The results indicated that the composite resin type did not significantly affect the amount of measured attrition (P=.15) but did significantly affect abrasive wear (P=.02). The conventional microfill composite resin (Heliomolar RO) exhibited significantly less abrasive wear than the nanohybrid material (Premise). There was no significant difference in the average size of the opposing enamel wear facet generated by the different composite resin materials. Heliomolar RO resulted in a significantly rougher surface within the wear track than either nanohybrid composite resin (Premise) or microhybrid composite resin (Point 4) but was not significantly different than nanofilled

  1. High Strength and Wear Resistant Aluminum Alloy for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.; Chen, Po Shou

    2003-01-01

    Originally developed by NASA as high performance piston alloys to meet U.S. automotive legislation requiring low exhaust emission, the novel NASA alloys now offer dramatic increase in tensile strength for many other applications at elevated temperatures from 450 F (232 C) to about 750 F (400 C). It is an ideal low cost material for cast automotive components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. It can be very economically produced from conventional permanent mold, sand casting or investment casting, with silicon content ranging from 6% to 18%. At high silicon levels, the alloy exhibits excellent thermal growth stability, surface hardness and wear resistant properties.

  2. Enhanced Wear Resistance of Transparent Epoxy Composite Coatings with Vertically Aligned Halloysite Nanotubes.

    Science.gov (United States)

    Song, Kenan; Chen, Dayong; Polak, Roberta; Rubner, Michael F; Cohen, Robert E; Askar, Khalid A

    2016-12-28

    The influence of nanoparticle orientation on wear resistance of transparent composite coatings has been studied. Using a nozzle spray coating method, halloysite nanotubes (HNTs) were aligned in the in-plane and out-of-plane directions and in various randomly oriented states. Nanoscratching, falling sand, and Taber Abrasion tests were used to characterize the wear resistance at different length scales. Composites consistently displayed better wear resistance than pure epoxy. Samples with out-of-plane particle orientations exhibited better wear-resistant behavior than those with in-plane particle distributions. In nanoscratching tests, the out-of-plane orientation decreases the normalized scratch volume by as much as 60% compared to pure epoxy. In the falling sand and Taber Abrasion tests, out-of-plane aligned halloysite particles resulted in surfaces with smaller roughness based on stylus profilometry and SEM observations. The decrease in roughness values after these wear tests can be as large as 67% from pure epoxy to composites. Composites with higher out-of-plane particle orientation factors exhibited better light transmittance after sand impingements and other wear tests. This study suggests a useful strategy for producing material systems with enhanced mechanical durability and more durable optical properties.

  3. Analysis and Modelling of Electrode Wear in Resistance Spot Welding

    DEFF Research Database (Denmark)

    Madsen, Anders; Pedersen, Kim; Friis, Kasper Storgaard

    2010-01-01

    A model describing electrode wear as a function of weld number, initial tip diameter, truncated cone angle, welding current and electrode force is proposed. Excellent agreement between the model and experimental results is achieved, showing that the model can describe the change in electrode tip...

  4. The comparative studies of ADI versus Hadfield cast steel wear resistance

    Directory of Open Access Journals (Sweden)

    Mieczysław Kaczorowski

    2011-04-01

    Full Text Available The results of comparative studies of wear resistance of ADI versus high manganese Hadfield cast steel are presented. For evaluation ofwear resistance three type of ADI were chosen. Two of them were of moderate strength ADI with 800 and 1000MPa tensile strength whilethe third was 1400MPa tensile strength ADI. The specimens were cut from ADI test YII type casting poured and heat treated in Institute ofFoundry in Krakow. The pin on disc method was used for wear resistance experiment. The specimens had a shape of 40mm long rod withdiameter 6mm. The load and speed were 100N and 0,54m/s respectively. It was concluded that the wear resistance of ADI is comparablewith high manganese cast steel and in case of low tensile grade ADI and is even better for high strength ADI than Hadfield steel.

  5. Features of Wear-Resistant Cast Iron Coating Formation During Plasma-Powder Surfacing

    Science.gov (United States)

    Vdovin, K. N.; Emelyushin, A. N.; Nefed'ev, S. P.

    2017-09-01

    The structure of coatings deposited on steel 45 by plasma-powder surfacing of white wear-resistant cast iron is studied. The effects of surfacing regime and additional production effects on the welding bath during surfacing produced by current modulation, accelerated cooling of the deposited beads by blowing with air, and accelerated cooling of the substrate with running water on the structure, are determined. A new composition is suggested for powder material for depositing wear-resistant and corrosion-resistant coatings on a carbon steel by the plasma-powder process.

  6. Comparative in vitro wear resistance of CAD/CAM composite resin and ceramic materials.

    Science.gov (United States)

    Zhi, Li; Bortolotto, Tissiana; Krejci, Ivo

    2016-02-01

    Composite resin is a promising option in computer-aided design and computer-aided manufacturing (CAD/CAM) dentistry; however, the wear resistance of composite resin remains a primary concern. The purpose of this in vitro study was to evaluate the wear resistance of 5 CAD/CAM materials (n=10), consisting of 4 composite resins (3M Lava Ultimate, Kerr experimental composite resin material, Vita Enamic, 3M Paradigm MZ100) and 1 ceramic (Vita Mark II) in contact with natural human enamel cusps. Specimens were loaded into a computer-controlled mastication simulator and subjected to 200000 mechanical cycles (49 N) against natural human enamel simultaneously with 500 thermal cycles (5°C to 50°C to 5°C). The wear resistance was analyzed by measuring the vertical substance loss (the maximum depth of the worn area) in the contact point area of the specimen. The worn surfaces were observed by scanning electron microscopy to determine the wear patterns. Vita Mark II exhibited the best wear resistance among the tested materials, followed by 3M Lava Ultimate, Vita Enamic, and 3M Paradigm MZ100. The Kerr experimental material exhibited the lowest wear resistance, yet its results were not significantly different from those of the 3 other composite resin blocks (P>.05). Within the limitations of this in vitro study, the wear resistance of composite resin blocks in contact with enamel cusps was significantly lower than that of a ceramic block. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  7. IMPROVEMENT OF WEAR-RESISTANCE AND SERVICE LIFE OF MULTI-DISK BRAKE MECHANISMS OF «BELARUS» TRACTOR BY LASER THERMAL HARDENING OF FAST WEARING PARTS

    OpenAIRE

    O. S. Kobjakov; N. V. Spiridonov; A. A. Barkun

    2008-01-01

    Problems concerning wear resistance improvement of «Belarus» tractor brake mechanism parts are considered in the paper. Properties of ВЧ-50-pig iron are investigated as a result of laser thermal hardening by various technological methods.

  8. NANOSCALE BOEHMITE FILLER FOR CORROSION AND WEAR RESISTANT POLYPHENYLENESULFIDE COATINGS.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2003-06-26

    The authors evaluated the usefulness of nanoscale boehmite crystals as a filler for anti-wear and anti-corrosion polyphenylenesulfide (PPS) coatings exposed to a very harsh, 300 C corrosive geothermal environment. The boehmite fillers dispersed uniformly into the PPS coating, conferring two advanced properties: First, they reduced markedly the rate of blasting wear; second, they increased the PPS's glass transition temperature and thermal decomposition temperature. The wear rate of PPS surfaces was reduced three times when 5wt% boehmite was incorporated into the PPS. During exposure for 15 days at 300 C, the PPS underwent hydrothermal oxidation, leading to the substitution of sulfide linkages by the sulfite linkages. However, such molecular alteration did not significantly diminish the ability of the coating to protect carbon steel against corrosion. In fact, PPS coating filled with boehmite of {le} 5wt% adequately mitigated its corrosion in brine at 300 C. One concern in using this filler was that it absorbs brine. Thus, adding an excess amount of boehmite was detrimental to achieving the maximum protection afforded by the coatings.

  9. Alternate paddle configuration for improved wear resistance in the saltstone mixer

    Energy Technology Data Exchange (ETDEWEB)

    Reigel, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fowley, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2013-09-23

    The Saltstone Production Facility has a 10-inch Readco-Kurimoto continuous mixer that mixes the premix dry feeds and low-level waste salt solution to make fresh (uncured) saltstone. Inspection of the mixer in January 2013 showed significant wear on the third, fourth and fifth paddle pairs after the conveying augers. A 2-inch Readco-Kurimoto continuous mixer was used to test alternate paddle configurations for use in the 10-inch mixer to decrease the wear rate on the paddles. Two wear tests were conducted to investigate a method of reducing wear on the mixer paddles. The first test (wear test 2a) had a paddle configuration similar to the currently installed 10-inch mixer in the SPF. This test established baseline wear. The second test (wear test 2b) had a reconfigured paddle arrangement that replaced the flat paddles with helical paddles for paddle pairs 2 - 6 and aligned paddle pair 1 with the augers. The intent of the reconfiguration was to more effectively convey the partially wetted dry feeds through the transition region and into the liquid feed where paddle wear is reduced due to dry feeds and salt solution being mixed at the intended water to premix ratio. The design of the helical paddles provides conveyance through the transition region to the liquid feed inlet. The alignment with the auger is aimed to provide a smoother transition (minimizing the discontinuity between the auger and paddle pair 1) into the downstream paddles. A soft metal with low wear resistance (6000 series aluminum) was used for the wear testing paddles to determine wear patterns while minimizing run time and maximizing wear rate. For the two paddle configurations tested using the scaled 2-inch Readco-Kurimoto continuous mixer, with the first six paddles after the augers replaced by the wear paddles and the remaining paddles were stainless steel. Since the 10-inch SPF mixer is designed with the liquid inlet centered over paddle pairs 5 and 6, the scaled 2-inch mixer was configured the

  10. Study on quantitative relation between characteristics of striature bionic coupling unit and wear resistance of gray cast iron

    Science.gov (United States)

    Pang, Zuobo; Zhou, Hong; Zhang, Peng; Cong, Dalong; Meng, Chao; Wang, Chuanwei; Ren, Luquan

    2015-03-01

    In order to improve the wear resistance of gray cast iron guide rail, striature bionic coupling units of different characteristics were manufactured by laser surface remelting. Wear behavior of gray cast iron with striature bionic coupling units has been studied under dry sliding condition at room temperature using a homemade linear reciprocating wear testing machine. The wear resistance was evaluated by means of weight loss measurement and wear morphology. The results indicated that there is a relationship between weight loss and the area of striature bionic coupling units and α: Δm = Δm0 - 0.0212S × cos α - 0.0241S × sin α.

  11. Microstructure and wear resistance of high chromium cast iron containing niobium

    Directory of Open Access Journals (Sweden)

    Zhang Zhiguo

    2014-05-01

    Full Text Available In the paper, the effect of niobium addition on the microstructure, mechanical properties and wear resistance of high chromium cast iron has been studied. The results show that the microstructure of the heat-treated alloys is composed of M7C3 and M23C6 types primary carbide, eutectic carbide, secondary carbide and a matrix of martensite and retained austenite. NbC particles appear both inside and on the edge of the primary carbides. The hardness of the studied alloys maintains around 66 HRC, not significantly affected by the Nb content within the selected range of 0.48%-0.74%. The impact toughness of the alloys increases with increasing niobium content. The wear resistance of the specimens presents little variation in spite of the increase of Nb content under a light load of 40 N. However, when heavier loads of 70 and 100 N are applied, the wear resistance increases with increasing Nb content.

  12. Wear resistance of alloy вт-22 with non-ferrous alloys at reverse

    Directory of Open Access Journals (Sweden)

    А.М. Хімко

    2010-01-01

    Full Text Available  The article presents the results of tests of non hardened titanium alloy ВТ-22 with aviation non-ferrous alloys in reverse sliding friction. The main objective of the work is the selection of the optimum combination of materials depending on changes in loading conditions. Study of alloy ВТ-22 wear resistance was carried out in pairs with БрОФ-10-1, БрБ2, БрАЖ-9-4, ВТ-22, МЛ5, Д16Т, 7Х21ГАН5Ш and 95Х18Ш. The dependencies of the materials wear at pressures 10, 20 and 30 Mpa we determined. The linear nature of titanium alloy wear curves indicates that the change in the wear mechanism occurs gradually. The histograms of non-ferrous materials wear and the total wear of the friction pair are presented. It is established that the bronze БрАЖ-9-4 is the most preferable material for contact with non hardened titanium alloy ВТ-22, the least wear among the tested materials. The established coefficients of the titanium alloy ВТ-22 friction in pair with aviation structural non-ferrous alloys are presented. The results of research will be relevant for the engineering industry, where non hardened titanium alloy ВТ-22 in pair with non-ferrous alloys is applied.

  13. Comparison of Wear Resistance Between Innovative Composites and Nano- and Microfilled Composite Resins

    Directory of Open Access Journals (Sweden)

    Asefi

    2016-02-01

    Full Text Available Background One of the most common causes of failure in class 2 posterior composite restorations is occlusal and proximal wear. Estelite composites used supra-nano monodispersing spherical fillers and a new photoinitiator, and the manufacturer claimed that the wear of these composites is less than 1 mm3 volumetric wear. Objectives Compare the wear resistance of new Estelite composites with that of other composites generations. Materials and Methods Thirty-five specimens were evaluated in five groups: three kinds of Estelite composites (Estelite Sigma Quick, Estelite Flow Quick, and Estelite Flow Quick High Flow, Filtek Z350, and Filtek Z250. All specimens were prepared in 25 mm disks and cured with laboratory light for 120 seconds (60 s for each side. Then, they were polished by 600 grit sand paper and stored for one week in distilled water at room temperature. We used a two-body abrasion test and the pin-on-disk method with distilled water as medium. All specimens were worn under 15 N load, 0.05 m/seconds speed, 100 m distance, and steatite ceramic balls antagonists. After wearing, we measured wear volume by calculating the wear track cross-section area with a profilometer and analyzed the data with the one-way analysis of variance (ANOVA test. Results The wear amounts of the composites are as follows in order: Estelite sigma quick (1886.9 ± 518.5 μm2, Estelite flow quick (2708.9 ± 578.1 μm2, Estelite high flow (3206 ± 2445.1 μm2, Filtek Z350 (3840 ± 1963.4 μm2, and Filtek Z250 (4667.2 ± 2351.1 μm2. No statistical difference was found among the groups (P value > 0.05. Conclusions Estelite sigma quick composite had wear resistance similar to that of nano- and microfilled composites. Estelite flowable composites demonstrated similar wear resistance to that of a posterior composite.

  14. Wear and abrasion resistance selection maps of biological materials.

    Science.gov (United States)

    Amini, Shahrouz; Miserez, Ali

    2013-08-01

    The mechanical design of biological materials has generated widespread interest in recent years, providing many insights into their intriguing structure-property relationships. A critical characteristic of load-bearing materials, which is central to the survival of many species, is their wear and abrasion tolerance. In order to be fully functional, protective armors, dentitious structures and dynamic appendages must be able to tolerate repetitive contact loads without significant loss of materials or internal damage. However, very little is known about this tribological performance. Using a contact mechanics framework, we have constructed materials selection charts that provide general predictions about the wear performance of biological materials as a function of their fundamental mechanical properties. One key assumption in constructing these selection charts is that abrasion tolerance is governed by the first irreversible damage at the contact point. The maps were generated using comprehensive data from the literature and encompass a wide range of materials, from heavily mineralized to fully organic materials. Our analysis shows that the tolerance of biological materials against abrasion depends on contact geometry, which is ultimately correlated to environmental and selective pressures. Comparisons with experimental data from nanoindentation experiments are also drawn in order to verify our predictions. With the increasing amount of data available for biological materials also comes the challenge of selecting relevant model systems for bioinspired materials engineering. We suggest that these maps will be able to guide this selection by providing an overview of biological materials that are predicted to exhibit the best abrasion tolerance, which is of fundamental interest for a wide range of applications, for instance in restorative implants and protective devices. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  15. Influence of aging solutions on wear resistance and hardness of selected resin-based dental composites.

    Science.gov (United States)

    Chladek, Grzegorz; Basa, Katarzyna; Żmudzki, Jarosław; Malara, Piotr; Nowak, Agnieszka J; Kasperski, Jacek

    2016-01-01

    The purpose of this study was to investigate the effect of different plasticizing aging solutions on wear resistance and hardness of selected universal resin-based dental composites. Three light cured (one nanofilled, two microhybride) and one hybride chemical cured composites were aged at 37 °C for 48 h in distillated water, ethyl alcohol solution or Listerine mouthwash. After aging the microhardness tests were carried out and then tribological tests were performed in the presence of aging solution at 37 °C. During wear testing coefficients of friction were determined. The maximal vertical loss in micrometers was determined with profilometer. Aging in all liquids resulted in a significant decrease in hardness of the test materials, with the largest values obtained successively in ethanol solution, mouthwash and water. The effect of the liquid was dependent on the particular material, but not the type of material (interpreted as the size of filler used). Introduction of mouthwash instead of water or ethanol solution resulted in a significant reduction in the coefficient of friction. The lowest wear resistance was registered after aging in ethanol and for the chemical cured hybrid composite, but the vertical loss was strongly material dependent. The effect of different aging solution, including commercial mouthrinse, on hardness and wear was material dependent, and cannot be deduced from their category or filler loading. There is no simple correlation between hardness of resin-based dental composites and their wear resistance, but softening of particular composites materials during aging leads to the reduction of its wear resistance.

  16. Cerium Addition Improved the Dry Sliding Wear Resistance of Surface Welding AZ91 Alloy

    Directory of Open Access Journals (Sweden)

    Qingqiang Chen

    2018-02-01

    Full Text Available In this study, the effects of cerium (Ce addition on the friction and wear properties of surface welding AZ91 magnesium alloys were evaluated by pin-on-disk dry sliding friction and wear tests at normal temperature. The results show that both the friction coefficient and wear rate of surfacing magnesium alloys decreased with the decrease in load and increase in sliding speed. The surfacing AZ91 alloy with 1.5% Ce had the lowest friction coefficient and wear rate. The alloy without Ce had the worst wear resistance, mainly because it contained a lot of irregularly shaped and coarse β-Mg17Al12 phases. During friction, the β phase readily caused stress concentration and thus formed cracks at the interface between β phase and α-Mg matrix. The addition of Ce reduced the size and amount of Mg17Al12, while generating Al4Ce phase with a higher thermal stability. The Al-Ce phase could hinder the grain-boundary sliding and migration and reduced the degree of plastic deformation of subsurface metal. Scanning electron microscopy observation showed that the surfacing AZ91 alloy with 1.5% Ce had a total of four types of wear mechanism: abrasion, oxidation, and severe plastic deformation were the primary mechanisms; delamination was the secondary mechanism.

  17. Cerium Addition Improved the Dry Sliding Wear Resistance of Surface Welding AZ91 Alloy.

    Science.gov (United States)

    Chen, Qingqiang; Zhao, Zhihao; Zhu, Qingfeng; Wang, Gaosong; Tao, Kai

    2018-02-06

    In this study, the effects of cerium (Ce) addition on the friction and wear properties of surface welding AZ91 magnesium alloys were evaluated by pin-on-disk dry sliding friction and wear tests at normal temperature. The results show that both the friction coefficient and wear rate of surfacing magnesium alloys decreased with the decrease in load and increase in sliding speed. The surfacing AZ91 alloy with 1.5% Ce had the lowest friction coefficient and wear rate. The alloy without Ce had the worst wear resistance, mainly because it contained a lot of irregularly shaped and coarse β-Mg 17 Al 12 phases. During friction, the β phase readily caused stress concentration and thus formed cracks at the interface between β phase and α-Mg matrix. The addition of Ce reduced the size and amount of Mg 17 Al 12 , while generating Al₄Ce phase with a higher thermal stability. The Al-Ce phase could hinder the grain-boundary sliding and migration and reduced the degree of plastic deformation of subsurface metal. Scanning electron microscopy observation showed that the surfacing AZ91 alloy with 1.5% Ce had a total of four types of wear mechanism: abrasion, oxidation, and severe plastic deformation were the primary mechanisms; delamination was the secondary mechanism.

  18. Effect of Boronizing on Microhardness and Wear Resistance of Steel AISI 1050 and Chilled Cast Iron

    Science.gov (United States)

    Calik, Adnan; Simsek, Mithat; Karakas, Mustafa Serdar; Ucar, Nazim

    2014-05-01

    Steel AISI 1050 (steel 50) and chilled cast iron are studied after 5-h solid-phase boronizing from a powder environment at 900 °C. The surfaces of the boronized specimens are studied by x-ray and electron microscopic analyses and their Vickers microhardness is measured. The wear resistance is determined by the pin-on-disc method.

  19. STRUCTURE FORMATION OF WEAR RESISTANT COMBINED TITANIUM-BASED COATINGS ON HIGH SPEED STEEL

    Directory of Open Access Journals (Sweden)

    M. A. Andreyev

    2006-01-01

    Full Text Available The paper proposes a technology of wear resistant coating formation on the basis of Ti. The combined technology includes electro arc evaporation in vacuum and ionic nitriding. Every technological stage of coating application has an influence on tiie structure formation of the combined coating.

  20. Effect of heat treatment on wear resistance of a grinding plate ...

    African Journals Online (AJOL)

    The effects of heat treatment on the hardness and by extension the wear resistance of locally produced grinding plate of known composition were investigated. Specimens were prepared from the grinding plate and were heat treated at 840°C, 860°C and 880°C and quenched at different rate. Some of the specimens were ...

  1. INFLUENCE OF ADDITIVES ON THE STRUCTURE FORMING OF ECONOMICALLY-ALLOYED WEAR RESISTING STEEL

    Directory of Open Access Journals (Sweden)

    A. I. Garost

    2007-01-01

    Full Text Available The characteristics of vanadium and nitrogencontaining economically-alloyed wear-resisting steels are investigated. The micro-composition and nature of nonmetallic impurities of steels with lowered content of manganese are studied. The optimal compositions of alloys for castings are offered.

  2. Wear analysis and cyclic fatigue resistance of electro discharge machined NiTi rotary instruments

    Directory of Open Access Journals (Sweden)

    F. Iacono

    2016-06-01

    Conclusions: The typical irregular surface of HyFlex EDM remained unaffected after multiple uses, confirming a high wear resistance. The new manufacturing process of electrical discharge machining had a substantial impact on fatigue lifetime of EDM files when compared with HyFlex CM. Within limitations of the present in vitro results, EDM files appeared suitable in shaping severely curved canals.

  3. Concrete surface with nano-particle additives for improved wearing resistance to increasing truck traffic.

    Science.gov (United States)

    2012-07-01

    This study focused on the use of nanotechnology in concrete to improve the wearing resistance of concrete. The nano : materials used were polymer cross-linked aerogels, carbon nanotubes, and nano-SiO2, nano-CaCO3, and nano-Al2O3 : particles. As an in...

  4. An in vitro investigation of wear resistance and hardness of composite resins.

    Science.gov (United States)

    Cao, Liqun; Zhao, Xinyi; Gong, Xu; Zhao, Shouliang

    2013-01-01

    The aim of the present study was to investigate the wear resistance and hardness of five kinds of composite resins. Sixty-five specimens were fabricated with one nano-hybrid (Charisma Diamond), two micro-hybrid (3MZ250, Clearfil AP-X) and two packable (3MP60, Surefil) composite resins, according to a randomized complete block design (n=13, 8 for wear test; 5 for hardness test). The composites were filled in a rectangular mold, and light polymerization. After storage in 37°C deionized water for 24h, all specimens were tested with a custom-made toothbrush machine with a stainless-steel ball as antagonist (3N loads, 1Hz, 6×10(5) cycles) immersed in calcium fluoride slurry. Wear volume, hardness and surface structure of each tested material was examined by a three-dimensional non-contact optical profilometer, Vickers indentation technique and scanning electron microscope. The volume loss ranked from least to most as follows: Charisma Diamond, P60, Z250, Clearfil AP-X and Surefil. Regarding hardness, the rank from highest to lowest as follows: Clearfil AP-X, P60, Surefil, Z250, Charisma Diamond. The interactions between wear resistance and microhardness were not significant. The custom-made machine is considered suitable to simulate sliding of an antagonist cusp on an opposing occlusal composite restoration. Nanofilled composite may have superior wear compared to other composite resins.

  5. Effect of quenching method on the wear and corrosion resistance of stainless steel AISI 420 (TYPE 30Kh13)

    Science.gov (United States)

    Sola, R.; Giovanardi, R.; Veronesi, P.; Poli, G.

    2013-03-01

    The effect of different kinds of quenching, i.e., laser, vacuum, and induction ones, on the mechanical properties and wear and corrosion resistances of stainless steel AISI 420 is studied. It is shown that all the three kinds of heat treatment raise considerably the wear resistance of the steel due to growth in the hardness. Laser and vacuum quenching also increases the corrosion resistance. After induction quenching the resistance to corrosion is lower than in untreated steel.

  6. Wear Resistance of Bulk-fill Composite Resin Restorative Materials Polymerized under different Curing Intensities.

    Science.gov (United States)

    Alkhudhairy, Fahad

    2017-01-01

    The aim of this study was to assess the wear resistance of four bulk-fill composite resin restorative materials cured using high- and low-intensity lights. Twenty-four samples were prepared from each composite resin material (Tetric N-Ceram, SonicFill, Smart Dentin Replacement, Filtek Bulk-Fill) resulting in a total of 96 samples; they were placed into a mold in a single increment. All of the 96 samples were cured using the Bluephase N light curing unit for 20 seconds. Half of the total specimens (n = 48) were light cured using high-intensity output (1,200 mW/cm2), while the remaining half (n = 48) were light cured using low-intensity output (650 mW/cm2). Wear was analyzed by a three-dimensional (3D) noncontact optical profilometer (Contour GT-I, Bruker, Germany). Mean and standard deviation (SD) of surface loss (depth) after 120,000 cycles for each test material was calculated and analyzed using one-way analysis of variance (ANOVA) with a significance level at p materials with each other without taking the curing light intensity into consideration (p = 0.352). A significant difference in the mean surface loss was observed between SonicFill cured using high-intensity light compared with that cured using low-intensity light (p resistance of the four bulk-fill composite resin restorative materials tested compared with lower curing light intensity (650 mW/cm2). Furthermore, SonicFill cured using low-intensity light was the most wear-resistant material tested, whereas Tetric N-Ceram cured using high-intensity light was the least wear resistant. The wear resistance was better with the newly introduced bulk-fill composite resins under low-intensity light curing.

  7. Factors Affecting the Wear Resistance of Forging Tools

    Directory of Open Access Journals (Sweden)

    Zwierzchowski M.

    2017-09-01

    Full Text Available The durability of forging tools is a function of many variables: tool heat treatment, surface quality, temperature, pressure, number of forgings, diffusion layers (nitriding and many others. The objective of study was to analyze and compare the working conditions of forging tools. For the analysis of selected flat surfaces of tools. Analyzed forging dies subjected to normal use. Presented results of laboratory tests . The effect of temperature and time on the properties of the surface layer of forging tools. The results were compared with the literature data. This article shows the results of microhardness tests for forging dies which have forged the corresponding number of forgings. The results of laboratory studies on microhardness of hot working steel 1.2344 in the furnace at various temperatures and time are also presented. The working conditions of the forging tools are very complex. The most often described in the literature are: thermal fatigue, abrasive wear, mechanical fatigue and cracks. The article discusses the effects of increased temperature on the surface properties of forging tools. Forging dies were made of hot work tool steel 1.2344. FEM modeling of changes in the surface layer should take into account changes in tool hardness as a function of time (number of forgings.

  8. The effects of homogenization treatment on wear resistance of AZ61 magnesium alloy fabricated by extrusion-shear process

    Science.gov (United States)

    Hu, H.-J.; Ying, Y.-L.; OU, Z.-W.; Wang, X.-Q.

    2017-12-01

    Wear resistance of extrusion shear-processed AZ61 magnesium samples with as-cast state and homogenization treatment state has been studied by wear tests using pin-on-disc experiments under dry sliding conditions. Wear rates and friction coefficients between AZ61 magnesium alloy and GCr15 steel have been used to evaluate wear resistances of AZ61 magnesium alloys, and obtained from dry sliding with different frequencies and loads. Scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDS) were used to analyze microstructures before and after the wear tests to find the wear mechanisms of AZ61 magnesium samples with as-cast state and homogenization treatment state. The wear resistances of the homogeneous state samples prepared by extrusion-shear process are close to those of as cast state, which are due to the little differences of microstructures. In addition, the wear mechanisms change from mild wear to severe wear with rise of exerted loads and reciprocating frequencies.

  9. Machining efficiency and wear resistance of nickel-titanium endodontic files.

    Science.gov (United States)

    Kazemi, R B; Stenman, E; Spångberg, L S

    1996-05-01

    Nickel-titanium endodontic files are more flexible than stainless steel. Little information is reported concerning machining efficiency and wear resistance of nickel titanium. This study assessed the dentin-machining ability and wear resistance of nickel titanium endodontic files in vitro. The method described earlier to assess machining efficiency and wear resistance of stainless steel files was used. Eight different types and brands of nickel titanium files were studied: Ultra-Flex Hedström, Ultra-Flex K, Mity Hedstrom, Mity K, Mity Turbo, Hedstrom Naviflex NT, NiTiFlex, and Hyflex X-file. Thirty files of each brand were evaluated. One-way ANOVA and t tests were performed to analyze the data. Considerable variation was found in matching efficiency and wear. The best initial machining ability of all nickel titanium instruments was recorded for the Hyflex-X file (0.60 +/- 0.16 mm2); the poorest performance was for the Mity Turbo file, which machined less than one third of the best performing instrument (0.19 +/- 0.12 mm2). We compared our results with results of a previous study of stainless steel endodontic files and concluded that nickel titanium instruments are as aggressive as or better than stainless steel instruments in removing dentin. They are also more durable than their stainless steel counterparts.

  10. Microstructure, microhardness and wear resistance of VCp/Fe surface composites fabricated in situ

    Science.gov (United States)

    Ye, Fangxia; Hojamberdiev, Mirabbos; Xu, Yunhua; Zhong, Lisheng; Zhao, Nana; Li, Yaping; Huang, Xing

    2013-09-01

    The vanadium carbide particles (VCp)/Fe surface composites were in situ fabricated by a technique combining infiltration casting with subsequent heat treatment. The effects of different heat treatment times on the phase evolution, microstructure, microhardness and wear resistance of the composite were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), Vickers hardness tester and wear resistance testing instrument, respectively. The results show that only graphite, α-Fe and V8C7 phases dominate in the composite after being heat treated at 1164 °C for 3 h. The amount of V8C7 decreases gradually from the top surface of the composite to the matrix mainly composed of gray cast iron. The average microhardness of the VCp/Fe surface composites varies according to the different reaction zones as follows: 505 HV0.1 (vanadium plate), 1096 HV0.1 (composite region), and 235 HV0.1 (iron matrix). The microhardness of the composite region is four times higher than that of the iron matrix and two times higher than that of the vanadium plate. This is attributed to the formation of vanadium carbide (V2C and V8C7) crystallites as reinforcement phases within the iron matrix. The VCp/Fe surface composites exhibit a good wear resistance under two-body abrasive wear test.

  11. Wear resistance analysis of the aluminum 7075 alloy and the nanostructured aluminum 7075 - silver nanoparticles composites

    Directory of Open Access Journals (Sweden)

    Estrada-Ruiz R.H.

    2016-01-01

    Full Text Available Nanostructured composites of the aluminum 7075 alloy and carbon-coated silver nanoparticles were synthetized by the mechanical milling technique using a high-energy mill SPEX 8000M; the powders generated were compacted, sintered and hot-extruded to produce 1 cm-diameter bars. The composites were then subjected to a wear test using a pin-on-disc device to validate the hypothesis that second phase-ductile nanometric particles homogenously distributed throughout the metalmatrix improve the wear resistance of the material. It was found that silver nanoparticles prevent the wear of the material by acting as an obstacle to dislocations movement during the plastic deformation of the contact surface, as well as a solid lubricant when these are separated from the metal-matrix.

  12. Friction and wear resistance of the electroless Ni-P-CNTs composite coatings

    Science.gov (United States)

    Zhao, G.; Zhang, H.; Wang, Z.

    2007-07-01

    Ni-P-Carbon nanotubes (CNTs) composite coatings as well as Ni-P-SiC and Ni-P coatings were prepared by electroless plating. The characteristics of the coatings were assessed by scanning electron microscopy and microhardness test. The friction and wear performance of the produced composite coatings were investigated at room temperature on a ball-on-disc type tribometer under non-lubricated conditions. The results show that the Ni-P-CNTs composite coatings exhibited lowed friction coefficient and better anti-wear performance compared to Ni-P-SiC and Ni-P coatings due to improved mechanical properties, self-lubrication and unique microstructure of the Ni-P-CNTs composite coatings. The effect of CNTs on the friction and wear resistance was discussed in detail.

  13. Mechanical Properties and Sliding-impact Wear Resistance of Self-adhesive Resin Cements.

    Science.gov (United States)

    Furuichi, T; Takamizawa, T; Tsujimoto, A; Miyazaki, M; Barkmeier, W W; Latta, M A

    2016-01-01

    The present study determined the mechanical properties and impact-sliding wear characteristics of self-adhesive resin cements. Five self-adhesive resin cements were used: G-CEM LinkAce, BeautiCem SA, Maxcem Elite, Clearfil SA Automix, and RelyX Unicem 2. Clearfil Esthetic Cement was employed as a control material. Six specimens for each resin cement were used to determine flexural strength, elastic modulus, and resilience according to ISO specification #4049. Ten specimens for each resin cement were used to determine the wear characteristics using an impact-sliding wear testing apparatus. Wear was generated using a stainless-steel ball bearing mounted inside a collet assembly. The maximum facet depth and volume loss were determined using a noncontact profilometer in combination with confocal laser scanning microscopy. Data were evaluated using analysis of variance followed by the Tukey honestly significantly different test (α=0.05). The flexural strength of the resin cements ranged from 68.4 to 144.2 MPa; the elastic modulus ranged from 4.4 to 10.6 GPa; and the resilience ranged from 4.5 to 12.0 MJ/m(3). The results for the maximum facet depth ranged from 25.2 to 235.9 μm, and volume loss ranged from 0.0107 to 0.5258 mm(3). The flexural properties and wear resistance were found to vary depending upon the self-adhesive resin cement tested. The self-adhesive cements tended to have lower mechanical properties than the conventional resin cement. All self-adhesive resin cements, apart from G-CEM LinkAce, demonstrated significantly poorer wear resistance than did the conventional resin cement.

  14. Nanostructured wear resistant coating for reversible cultivator shovels: An experimental investigation

    Energy Technology Data Exchange (ETDEWEB)

    Dave, V., E-mail: vdaditya1000@gmail.com [Department of Electrical Engineering,College of Technology and Engineerin, MPUAT Udaipur, 313001,India (India); Rao, G. P., E-mail: ragrao38@gmail.com; Tiwari, G. S., E-mail: tiwarigsin@yahoo.com [Department of Farm Machinery and Power Engineering, MPUAT Udaipur, 313001,India (India); Sanger, A., E-mail: amitsangeriitr@gmail.com; Kumar, A., E-mail: 01ashraj@gmail.com; Chandra, R., E-mail: ramesfic@gmail.com [Institute Instrumentation Centre, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

    2016-04-13

    Cultivator, one of the agriculture farm tool, extensively suffers from the wear problem. In this paper, we report nanostructured chromium nitrite (CrN) coating for the cultivator shovels to mitigate wear problem. The (CrN) coating was developed using DC magnetron sputtering technique at 200 °C. The structural, morphological, hydrophobic and wear properties were investigated using X-ray diffractometer, scanning electron microscope, contact angle goniometer and custom designed soil bin assembly. The XRD reveals that the deposited coating was polycrystalline in nature with cubic structure. Also, The deposited coating was found to be anti wear resistant as well as hydrophobic in nature. The gravimetric wear for the coating developed at 200 °C coated was found out to be 8.15 gm and for non coated it was 14.48 gm tested for 100 hrs. The roughness of the coating plays an important role in determining the hydrophobicity of the coated film. Roughness and contact angle measured for 200 °C coated shovel was found out to be 11.17 nm and 105 ° respectively.

  15. Analysis of the relationship between the surface hardness and wear resistance of indirect composites used as veneer materials.

    Science.gov (United States)

    Faria, Adriana Cláudia Lapria; Benassi, Ubiratan Menezes; Rodrigues, Renata Cristina Silveira; Ribeiro, Ricardo Faria; Mattos, Maria da Gloria Chiarello de

    2007-01-01

    This study evaluated the surface hardness and wear resistance of indirect composites (Artglass and Solidex) and the existence of a correlation between these properties. Twenty-four specimens (12 per material) were fabricated using a polytetrafluoroethylene matrix (5.0 mm in diameter; 7.0 mm high) following an incremental technique. Polymerization was done with a xenon stroboscopic light curing unit. After polishing, the specimens were stored in water at 37 degrees C during either 1 day (n=6 per material) or 55 days (n=6 per material), after which Vickers surface hardness and wear resistance were assessed. Data were analyzed statistically by unpaired Student t-test, two-way ANOVA and Tukey's test. SURFACE HARDNESS: Artglass had higher surface hardness than Solidex after 1-day immersion period (pmaterials (p>0.05). Comparing the materials at both periods, Artglass means differed significantly to each other (p0.05). WEAR RESISTANCE: Solidex had higher wear than Artglass after 1-day immersion period (pmaterials after 55 days (p>0.05). Comparing the materials at both periods, Artglass means differed significantly to each other (p0.05). These results suggest that Artglass was better than Solidex in terms of hardness and wear resistance after 1-day water immersion. However, it was more susceptible to degradation, showing greater wear after 55 days. In conclusion, there was an inverse correlation between surface hardness and wear resistance for both Artglass and Solidex indirect composites, that is the higher the hardness, the lower the wear.

  16. Effect of thermal fatigue on the wear resistance of graphite cast iron with bionic units processed by laser cladding WC

    Science.gov (United States)

    Jing, Zhengjun; Zhou, Hong; Zhang, Peng; Wang, Chuanwei; Meng, Chao; Cong, Dalong

    2013-04-01

    Thermal fatigue and wear exist simultaneously during the service life of brake discs. Previous researchers only studied thermal fatigue resistance or abrasion resistance of compact graphite cast iron (CGI), rather than combining them together. In this paper, wear resistance after thermal fatigue of CGI was investigated basing on the principle of bionics, which was close to actual service condition of the brake discs. In the meanwhile, the effect of thermal fatigue on wear resistance was also discussed. Non-smooth bionic units were fabricated by laser cladding WC powder with different proportions (50 wt.%, 60 wt.%, 70 wt.%). Microstructure and microhardness of the units were investigated, and wear mass losses of the samples were also compared. The results indicate that thermal fatigue has a negative effect on the wear resistance. After the same thermal fatigue cycles times, the wear resistance of laser cladding WC samples is superior to that of laser remelting ones and their wear resistance enhances with the increase of WC content.

  17. Hardness and Wear Resistance of TiC-Fe-Cr Locally Reinforcement Produced in Cast Steel

    Directory of Open Access Journals (Sweden)

    Olejnik E.

    2016-06-01

    Full Text Available In order to increase wear resistance cast steel casting the TiC-Fe-Cr type composite zones were fabricated. These zones were obtained by means of in situ synthesis of substrates of the reaction TiC with a moderator of a chemical composition of white cast iron with nickel of the Ni-Hard type 4. The synthesis was carried out directly in the mould cavity. The moderator was applied to control the reactive infiltration occurring during the TiC synthesis. The microstructure of composite zones was investigated by electron scanning microscopy, using the backscattered electron mode. The structure of composite zones was verified by the X-ray diffraction method. The hardness of composite zones, cast steel base alloy and the reference samples such as white chromium cast iron with 14 % Cr and 20 % Cr, manganese cast steel 18 % Mn was measured by Vickers test. The wear resistance of the composite zone and the reference samples examined by ball-on-disc wear test. Dimensionally stable composite zones were obtained containing submicron sizes TiC particles uniformly distributed in the matrix. The macro and microstructure of the composite zone ensured three times hardness increase in comparison to the cast steel base alloy and one and a half times increase in comparison to the white chromium cast iron 20 % Cr. Finally ball-on-disc wear rate of the composite zone was five times lower than chromium white cast iron containing 20 % Cr.

  18. Genipin crosslinking of cartilage enhances resistance to biochemical degradation and mechanical wear.

    Science.gov (United States)

    McGann, Megan E; Bonitsky, Craig M; Jackson, Mariah L; Ovaert, Timothy C; Trippel, Stephen B; Wagner, Diane R

    2015-11-01

    Collagen crosslinking enhances many beneficial properties of articular cartilage, including resistance to chemical degradation and mechanical wear, but many crosslinking agents are cytotoxic. The purpose of this study was to evaluate the effectiveness of genipin, a crosslinking agent with favorable biocompatibility and cytotoxicity, as a potential treatment to prevent the degradation and wear of articular cartilage. First, the impact of genipin concentration and treatment duration on the viscoelastic properties of bovine articular cartilage was quantified. Next, two short-term (15 min) genipin crosslinking treatments were chosen, and the change in collagenase digestion, cartilage wear, and the friction coefficient of the tissue with these treatments was measured. Finally, chondrocyte viability after exposure to these genipin treatments was assessed. Genipin treatment increased the stiffness of healthy, intact cartilage in a dose-dependent manner. The 15-min crosslinking treatments improved cartilage's resistance to both chemical degradation, particularly at the articular surface, and to damage due to mechanical wear. These enhancements were achieved without sacrificing the low coefficient of friction of the tissue and at a genipin dose that preserved chondrocyte viability. The results of this study suggest that collagen crosslinking via genipin may be a promising preventative treatment to slow the degradation of cartilage. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  19. Effect of post weld heat treatment on wear resistance of hot forging cast steel die coated with surfacing layer

    Directory of Open Access Journals (Sweden)

    Xu Wujiao

    2015-01-01

    Full Text Available The wear resistance capability of die surfacing layer under different Post Weld Heat Treatments (PWHT was analysed by Finite Element Method (FEM simulation and experiments. Taking the hot forging process of crankshaft as example, a wear model of hot forging die coated with surfacing layer was established by the software DEFORM-3D. The simulation results indicate that the wear resistance capability of the die surfacing layer is optimal when tempering temperature and holding time are 550 ∘C and 4h respectively. To verify the wear calculation result, 16 groups of different PWHT orthogonal wear tests were performed under atmospheric condition at 400 ∘C. The wear test result shows a good agreement with the FEM simulation result. SEM observation of the wear debris shows that oxidative wear plays a dominant role in 400 ∘C among 16 specimens. Furthermore, when tempering temperature and holding time are 550 ∘C and 4h respectively, the alloy carbide dispersively distributes in the metallographic structure, which can improve the wear resistance of the surfacing.

  20. Effect of post-welding heat treatment on wear resistance of cast-steel die with surfacing layer

    Directory of Open Access Journals (Sweden)

    Xu Wujiao

    2015-01-01

    Full Text Available The wear resistance capability of die surfacing layer under different Post-Welding Heat Treatments (PWHT was analysed by Finite Element (FE simulation and experiments. Taking hot forging process of a crankshaft as an example, a wear model of the hot forging die coated with surfacing layer was established using FE software DEFORM-3D. The simulation results indicated that the wear resistance capability of the die surfacing layer is optimal when tempering temperature and holding time are 550 °C and 4 h respectively. To verify the wear computational results, 16 groups of PWHT orthogonal wear tests were performed at a temperature of 400 °C, which is a similar temperature to that occurs in an actual hot forging die. The wear-test result showed a good agreement with the FE simulation. SEM observation of the wear debris on 16 specimens showed that oxidative wear is dominant when the temperature was in 400 °C. Furthermore, when tempering temperature and holding time were 550 °C and 4 h respectively, the carbide alloy dispersively distributes in the metallographic structure, which helps to improve the wear resistance of the surfacing layer.

  1. Selected Plastics Wear Resistance to Bonded Abrasive Particles Compared to Some Ferrous Materials

    Directory of Open Access Journals (Sweden)

    Milan Brožek

    2015-01-01

    Full Text Available Plastics are macromolecular materials without we cannot imagine any branch of human activity with. Plastics have unique properties, often very different from metals. At the choice of the concrete plastic for the concrete application it is necessary to evaluate its mechanical, physical, chemical and technological properties. In last years producers offer also plastics for production of parts exposed to different types of wear. In the contribution the results of wear resistance studying of 10 types of plastics (PTFE, PVC, POM-C, PC, PETP, PEEK, PA66, PP, PA6E and PE-UHMW of one producer are published and compared with test results of four different Fe alloys (grey iron, structural steel, cast steel wear resistant and high-speed steel. The laboratory tests were carried out using the pin-on-disk machine with abrasive cloth (according to ČSN 01 5084, when the abrasive clothes of three different grits (240, 120 and 60 were used. It corresponds to the average abrasive grain sizes of 44.5 µm, 115.5 µm and 275 µm. During the test the test sample was pressed to the abrasive cloth by the pressure of 0.1 MPa. The wear intensity was assessed by the volume, weight and length losses of tested samples. The technical-economical evaluation was the part of the carried out tests. It was univocally proved that at the intensive abrasive wear using the abrasive cloth the best results shows the High-Speed Steel HSS Poldi Radeco 19 810 according to ČSN 41 9810, although its price is relatively high. Other tested Fe alloys, namely grey iron according to ČSN 42 2415, structural steel 11 373 according to ČSN 41 1373 and wear resistant cast steel VPH 6 showed also very favourable properties at the material low price. In comparison with Fe alloys the wear of all plastics was considerably higher and the plastics were considerably more expensive.

  2. IMPROVEMENT OF WEAR-RESISTANCE AND SERVICE LIFE OF MULTI-DISK BRAKE MECHANISMS OF «BELARUS» TRACTOR BY LASER THERMAL HARDENING OF FAST WEARING PARTS

    Directory of Open Access Journals (Sweden)

    O. S. Kobjakov

    2008-01-01

    Full Text Available Problems concerning wear resistance improvement of «Belarus» tractor brake mechanism parts are considered in the paper. Properties of ВЧ-50-pig iron are investigated as a result of laser thermal hardening by various technological methods.

  3. Effect of Anode Pulse-Width on the Microstructure and Wear Resistance of Microarc Oxidation Coatings

    OpenAIRE

    Zhen-Wei Li; Shi-Chun Di

    2017-01-01

    Microarc oxidation (MAO) coatings were prepared on 2024-T4 aluminum alloys using a pulsed bipolar power supply at different anode pulse-widths. After the MAO coatings were formed, the micropores and microcracks on the surface of the MAO coatings were filled with Fluorinated ethylene propylene (FEP) dispersion for preparing MAO self-lubricating composite coatings containing FEP. The effect of the anode pulse-width on the microstructure and wear resistance of the microarc oxidation coatings was...

  4. Abrasive Wear Resistance of Overlay Composite Alloy with Addition of Carbide Powders

    OpenAIRE

    Tadao, ARAKI; Minoru, NISHIDA; Akio, HIROSE; Kouji, YANO; HIroshi, FUJITA; Faculty of Eng., Ehime University; Faculty of Eng., Ehime University; Faculty of Eng., Osaka University; Kawasaki Steel Co., Ltd.; Tokuden Co., Ltd.

    1993-01-01

    The overall objective of this project is to provide data showing how carbide powder in addition to base alloy powder can be used effectively to increase hardness of overlay alloy and resistance to abrasive wear. An experimental study was performed to examine combinations of base alloy powders and reinforcing powders. The base alloy powders considered were stainless steel, Ni-base alloy, Co-base alloy and high speed steel powder, while reinforcing powders considered were metal-carbide and cera...

  5. Microstructure and wear behaviors of laser clad NiCr/Cr3C2-WS2 high temperature self-lubricating wear-resistant composite coating

    Science.gov (United States)

    Yang, Mao-Sheng; Liu, Xiu-Bo; Fan, Ji-Wei; He, Xiang-Ming; Shi, Shi-Hong; Fu, Ge-Yan; Wang, Ming-Di; Chen, Shu-Fa

    2012-02-01

    The high temperature self-lubricating wear-resistant NiCr/Cr3C2-30%WS2 coating and wear-resistant NiCr/Cr3C2 coating were fabricated on 0Cr18Ni9 austenitic stainless steel by laser cladding. Phase constitutions and microstructures were investigated, and the tribological properties were evaluated using a ball-on-disc wear tester under dry sliding condition at room-temperature (17 °C), 300 °C and 600 °C, respectively. Results indicated that the laser clad NiCr/Cr3C2 coating consisted of Cr7C3 primary phase and γ-(Fe,Ni)/Cr7C3 eutectic colony, while the coating added with WS2 was mainly composed of Cr7C3 and (Cr,W)C carbides, with the lubricating WS2 and CrS sulfides as the minor phases. The wear tests showed that the friction coefficients of two coatings both decrease with the increasing temperature, while the both wear rates increase. The friction coefficient of laser clad NiCr/Cr3C2-30%WS2 is lower than the coating without WS2 whatever at room-temperature, 300 °C, 600 °C, but its wear rate is only lower at 300 °C. It is considered that the laser clad NiCr/Cr3C2-30%WS2 composite coating has good combination of anti-wear and friction-reducing capabilities at room-temperature up to 300 °C.

  6. Nano-hardness, wear resistance and pseudoelasticity of hafnium implanted NiTi shape memory alloy.

    Science.gov (United States)

    Zhao, Tingting; Li, Yan; Liu, Yong; Zhao, Xinqing

    2012-09-01

    NiTi shape memory alloy was modified by Hf ion implantation to improve its wear resistance and surface integrity against deformation. The Auger electron spectroscopy and x-ray photoelectron spectroscopy results indicated that the oxide thickness of NiTi alloy was increased by the formation of TiO₂/HfO₂ nanofilm on the surface. The nano-hardness measured by nano-indentation was decreased even at the depth larger than the maximum reach of the implanted Hf ion. The lower coefficient of friction with much longer fretting time indicated the remarkable improvement of wear resistance of Hf implanted NiTi, especially for the sample with a moderate incident dose. The formation of TiO₂/HfO₂ nanofilm with larger thickness and decrease of the nano-hardness played important roles in the improvement of wear resistance. Moreover, Hf implanted NiTi exhibited larger pseudoelastic recovery strain and retained better surface integrity even after being strained to 10% as demonstrated by in situ scanning electron microscope observation. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  7. Preparation and Properties of Superamphiphobic Wear-resistance PPS-based Coating

    Directory of Open Access Journals (Sweden)

    WANG Huai-yuan

    2017-01-01

    Full Text Available Superamphiphobic wear-resistance PPS-based coatings were prepared by a simple spraying method with a pore-forming reagent of NH4HCO3 and nano-filler of carbon nanotubes (CNTs.The surface morphology and the hydrophobicity,oleophobicity of the coating were analyzed by scanning electron microscope (SEM and contact angle meter.The wear-resistance of the coating was verified by sanding method with given load.The results indicate that a rough surface is obtained after pore-forming,and the porous structures in combination with the CNTs construct the special micro/nano-scale network structures.When the mass fraction of NH4HCO3 is 5%,the contact angles of the coating for water,glycerine and ethylene glycol are 162°,158° and 152°,showing superamphiphobic property.After polished 10000 times by abrasive paper,the coating shows slight friction marks and remains high hydrophobicity,exhibiting excellent wear-resistance.

  8. Effect of dry cryogenic treatment on Vickers hardness and wear resistance of new martensitic shape memory nickel-titanium alloy

    National Research Council Canada - National Science Library

    Vinothkumar, Thilla Sekar; Kandaswamy, Deivanayagam; Prabhakaran, Gopalakrishnan; Rajadurai, Arunachalam

    2015-01-01

    The aim of this study is to investigate the role of dry cryogenic treatment (CT) temperature and time on the Vickers hardness and wear resistance of new martensitic shape memory (SM) nickel-titanium (NiTi) alloy...

  9. Scanning probe microscopy estimation of the wear resistance of the surface of a modified PVC film

    Science.gov (United States)

    Kochetkova, A. S.; Gorbushin, P. N.; Sosnov, E. A.; Kolert, K.; Malygin, A. A.

    2017-04-01

    An atomic force microscopy technique is proposed to determine the wear resistance of a protective coating deposited by the sol-gel method on the surface of a polyvinylchloride film. The force of action of a probe on a sample is estimated under various scanning conditions. It is shown that the obtained data on the resistance of a coating to the action of a probe in the contact mode can be used to qualitatively estimate the adhesion of the coating to the surface of a polymer matrix.

  10. Influence of Heat Treatment on Abrasive Wear Resistance of Silumin Matrix Composite Castings

    Directory of Open Access Journals (Sweden)

    Gawdzińska K.

    2016-03-01

    Full Text Available The authors attempted at examining the effect of heat treatment on abrasive wear resistance of metal composite castings. Metal matrix composites were made by infiltrating preforms created from unordered short fibers (graphite or silumin with liquid aluminium alloy AlSi12(b. Thus prepared composites were subject to solution heat treatment at a temperature of 520°C for four hours, then aging at a temperature of 220°C for four hours. Abrasion resistance of the material was tested before and after thermal treatment.

  11. A nanometric cushion for enhancing scratch and wear resistance of hard films

    Directory of Open Access Journals (Sweden)

    Katya Gotlib-Vainshtein

    2014-07-01

    Full Text Available Scratch resistance and friction are core properties which define the tribological characteristics of materials. Attempts to optimize these quantities at solid surfaces are the subject of intense technological interest. The capability to modulate these surface properties while preserving both the bulk properties of the materials and a well-defined, constant chemical composition of the surface is particularly attractive. We report herein the use of a soft, flexible underlayer to control the scratch resistance of oxide surfaces. Titania films of several nm thickness are coated onto substrates of silicon, kapton, polycarbonate, and polydimethylsiloxane (PDMS. The scratch resistance measured by scanning force microscopy is found to be substrate dependent, diminishing in the order PDMS, kapton/polycarbonate, Si/SiO2. Furthermore, when PDMS is applied as an intermediate layer between a harder substrate and titania, marked improvement in the scratch resistance is achieved. This is shown by quantitative wear tests for silicon or kapton, by coating these substrates with PDMS which is subsequently capped by a titania layer, resulting in enhanced scratch/wear resistance. The physical basis of this effect is explored by means of Finite Element Analysis, and we suggest a model for friction reduction based on the "cushioning effect” of a soft intermediate layer.

  12. Wear resistant composite structure of vitreous carbon containing convoluted fibers. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Burton, R.G.; Burton, R.A.

    1996-05-28

    Energy Related Inventions Program Number 613 was a two year program to commercialize a unique new wear material, Metal Reinforced Carbon Composite, MRCC. The program was designed to manufacture sample components of MRCC for evaluation by potential users and manufacturers. As a result of the program Burton Technologies Inc. and Rotary Power International are forming a joint company to manufacture, market and license MRCC materials to a wide range of industries.

  13. The Tribological Performance of Hardfaced/ Thermal Sprayed Coatings for Increasing the Wear Resistance of Ventilation Mill Working Parts

    Directory of Open Access Journals (Sweden)

    A. Vencl

    2015-09-01

    Full Text Available During the coal pulverizing, the working parts of the ventilation mill are being worn by the sand particles. For this reason, the working parts are usually protected with materials resistant to wear (hardfaced/thermal sprayed coatings. The aim of this study was to evaluate the tribological performance of four different types of coatings as candidates for wear protection of the mill’s working parts. The coatings were produced by using the filler materials with the following nominal chemical composition: NiFeBSi-WC, NiCrBSiC, FeCrCTiSi, and FeCrNiCSiBMn, and by using the plasma arc welding and flame and electric arc spraying processes. The results showed that Ni-based coatings exhibited higher wear resistance than Fe-based coatings. The highest wear resistance showed coating produced by using the NiFeBSi-WC filler material and plasma transferred arc welding deposition process. The hardness was not the only characteristic that affected the wear resistance. In this context, the wear rate of NiFeBSi-WC coating was not in correlation with its hardness, in contrast to other coatings. The different wear performance of NiFeBSi-WC coating was attributed to the different type and morphological features of the reinforcing particles (WC.

  14. Wear resistance of laser-deposited boride reinforced Ti-Nb-Zr-Ta alloy composites for orthopedic implants

    Energy Technology Data Exchange (ETDEWEB)

    Samuel, Sonia [Department of Materials Science and Engineering University of North Texas, Denton, TX (United States); Nag, Soumya [Department of Materials Science and Engineering Ohio State University, Columbus, OH (United States); Scharf, Thomas W.; Banerjee, Rajarshi [Department of Materials Science and Engineering University of North Texas, Denton, TX (United States)

    2008-04-01

    The inherently poor wear resistance of titanium alloys limits their application as femoral heads in femoral (hip) implants. Reinforcing the soft matrix of titanium alloys (including new generation {beta}-Ti alloys) with hard ceramic precipitates such as borides offers the possibility of substantially enhancing the wear resistance of these composites. The present study discusses the microstructure and wear resistance of laser-deposited boride reinforced composites based on Ti-Nb-Zr-Ta alloys. These composites have been deposited using the LENS{sup TM} process from a blend of elemental Ti, Nb, Zr, Ta, and boron powders and consist of complex borides dispersed in a matrix of {beta}-Ti. The wear resistance of these composites has been compared with that of Ti-6Al-4V ELI, the current material of choice for orthopedic femoral implants, against two types of counterfaces, hard Si{sub 3}N{sub 4} and softer SS440C stainless steel. Results suggest a substantial improvement in the wear resistance of the boride reinforced Ti-Nb-Zr-Ta alloys as compared with Ti-6Al-4V ELI against the softer counterface of SS440. The presence of an oxide layer on the surface of these alloys and composites also appears to have a substantial effect in terms of enhanced wear resistance.

  15. Microstructure and wear resistance of NiCrBSi laser clad layer on titanium alloy substrate

    Energy Technology Data Exchange (ETDEWEB)

    Sun, R.L.; Yang, D.Z.; Guo, L.X.; Dong, S.L. [Harbin Inst. of Technol. (China). Sch. of Mater. Sci. and Eng.

    2000-10-23

    Laser cladding of NiCrBSi powders on Ti-6Al-4V alloy substrate was performed, and microstructure, microhardness and wear resistance of the clad layers were evaluated. Results show that the laser clad layer is divided into three regions: the clad, the dilution and the heat-affected zones. In the clad zone, fine particles of TiB{sub 2}, TiC and M{sub 23}(CB){sub 6} are distributed in the matrix of the primary {gamma}-Ni and the multi-phase eutectics consisting of {gamma}-Ni, Ni{sub 3}B and silicides. Microhardness of the clad zone is very high, being approximately HV 1000. The dilution zone is a mixture of melted Ni-base and Ti-base alloys, and possesses a characteristic of directional crystallization. The heat-affected zone has an acicular martensitic structure, and the microhardness is HV 360-380. Compared to titanium alloy, the wear resistance of clad layer is improved. The mechanism of wearing of clad layer is a mixed type of slight peeling-off and abrasion. (orig.)

  16. Initial Assessment of Abrasive Wear Resistance of Austempered Cast Iron with Vermicular Graphite

    Directory of Open Access Journals (Sweden)

    Soiński M. S.

    2014-10-01

    Full Text Available The work compares the abrasive wear resistance of cast iron containing vermicular graphite, measured in the as-cast state and after austempering carried out at 290°C, 340°C, or 390°C. Theexaminations were performed by means of the T-01M tribological tester using the pin-on-disc configuration. Specimens used for examinations were taken from the end tabs of the tensile specimens, these being cut out of the test walls of the double-leg keel block test castings. Examinations proved that the austempering process increases the abrasive wear resistance of vermicular cast iron by several times as compared with the as-cast material. A tendency for a slight decrease in abrasive wear with an increase in austempering temperature can be stated. The coefficient of friction took a little higher values for cast iron after thermal treatment than for the as-cast material. The work was completed with roughness examination by means of electron scanning microscopy.

  17. Wear Resistance and Mechanical Behaviour of Epoxy/Mollusk Shell Biocomposites developed for Structural Applications

    Directory of Open Access Journals (Sweden)

    I.O. Oladele

    2016-09-01

    Full Text Available Epoxy resin is one of the strongest commercially exploitable thermosetting polymers in the polymer family; however its expensive nature in comparison with other thermosetting polymers such as vinylester and polyester limits its applications as a structural material. Inexpensive fillers on the other hand, especially those derived from agro-industrial wastes are very important in reducing the overall cost of polymer composites and furthermore influential in enhancing some of their engineering properties. In the present study, the wear resistance and mechanical behaviour of epoxy polymer matrix filled with <75 and 75 μm calcined particles of African land snail shells have been comparatively investigated. The wear resistance and the mechanical behaviour of the composites were studied via Taber Abraser and INSTRON universal testing machine. Also, the elemental constituents of the calcined snail shell and the epoxy biocomposites were characterized by X-Ray Fluorescence Spectroscopy and Scanning Electron Microscopy/Energy Dispersion Spectroscopy. From the experimental results, it was observed that, at the highest filler loading, smaller particle size presented a biocomposite with significant enhancement in wear and mechanical properties. However, it was also observed that increase in particle size showed no significant enhancement in the mechanical properties of the biocomposites.

  18. Recycled Aluminium Cans/Eggshell Composites: Evaluation of Mechanical and Wear Resistance Properties

    Directory of Open Access Journals (Sweden)

    J.O. Agunsoye

    2015-03-01

    Full Text Available Aluminium based metal matrix composites have been produced from recycled aluminium cans and 150µm sized eggshell particles using a stir cast process. The mechanical properties of the control and aluminium can/eggshell composites produced have been investigated. The microstructures of the aluminium can/eggshell composites were examined with the aids of Scanning Electron Microscope (SEM after the sample surfaces have been carefully prepared and etched with aqueous solution of 0.5 cm3 nitric acid. Micrographs revealed that there was a homogenous distribution of eggshell particles within the aluminium can matrix. An indication of effective stirring action during the melting process. The wear resistance was also investigated under different applied loads (6 to 14 N on an abrasive surface emery paper of grade 220. The results revealed an increase in Young’s modulus of elasticity and yield stress from 1,206.45 and 50.23 Mpa respectively of the cast aluminium can with 0 % eggshell particle to the maximum of 3,258.87and 73.2 MPa of aluminium can/12 % eggshell composites. The hardness values increased from 66.23 to 75.13 VN. There was a gradual increase in wear rate of the tested samples as the applied load increased. However, the wear resistance of the aluminium can/6 % eggshell and aluminium can/12 % eggshell composites increased significantly. Hence, recycling of aluminium cans and eggshells can be harnessed into development of useful engineering metal matrix composite materials.

  19. Wear resistant PTFE thin film enabled by a polydopamine adhesive layer

    Energy Technology Data Exchange (ETDEWEB)

    Beckford, Samuel [Microelectronics-Photonics Graduate Program, University of Arkansas, Fayetteville, AR 72701 (United States); Zou, Min, E-mail: mzou@uark.edu [Department of Mechanical Engineering, University of Arkansas, 863 West Dickson Street, Fayetteville, AR 72701 (United States); Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR 72701 (United States)

    2014-02-15

    The influence of a polydopamine (PDA) adhesive layer on the friction and wear resistance of polytetrafluoroethylene (PTFE) thin films coated on stainless steel was investigated. The friction and wear tests were carried out using a ball on flat configuration under a normal load of 50 g, sliding speed of 2.5 mm/s, and stroke length of 15 mm. It is found that the PDA/PTFE film is able to withstand approximately 500 times more rubbing cycles than the PTFE film alone. X-ray photoelectron spectroscopy (XPS) results show that a tenacious layer of PTFE remains adhered to the PDA layer, which enables the durability of the PDA/PTFE film. Because of the relatively low thickness of the film, PDA/PTFE shows great potential for use in applications where durable, thin films are desirable.

  20. Wear Resistance of Steel 20MnCr5 After Surfacing with Micro-jet Cooling

    Directory of Open Access Journals (Sweden)

    Tarasiuk W.

    2016-09-01

    Full Text Available This paper presents results of experimental research concerning the impact of an innovative method of micro-jet cooling on the padding weld performed with MIG welding. Micro-jet cooling is a novel method patented in 2011. It enables to steer the parameters of weld cooling in a precise manner. In addition, various elements which may e.g. enhance hardness or alter tribological properties can be entered into its top surface, depending on the applied cooling gas. The material under study was steel 20MnCr5, which was subject to the welding process with micro-jet cooling and without cooling. Nitrogen was used as a cooling gas. The main parameter of weld assessment was wear intensity. The tests were conducted in a tribological pin-on-disc type position. The following results exhibit growth at approximately 5% in wear resistance of padding welds with micro-jet cooling.

  1. Inventions in the nanotechnological area considerably increase wear- and chemical resistance of construction products

    Directory of Open Access Journals (Sweden)

    VLASOV Vladimir Alexeevich

    2014-08-01

    Full Text Available The invention «Reinforced flaked element made of natural or conglomerate stone and its multilayer protective coating (RU 2520193» is referred to construction materials. Reinforced flaked element made of natural or conglomerate stone consists of: natural or conglomerate materials as the basis; multilayer coating which protects the mentioned basis from chemical substances and wearing mechanical factors influencing on this element where the multilayer coating includes at least three layers formed by one or many film-forming compositions which comprise top layer with scratch-resistant nanoparticles and encircled with polyester, melamine, phenolic, acryl or epoxy resin (or any combination of them which provides protection against scratches; damper intermediate layer made of epoxy and/or acryl resin which provides impact resistant; lower layer adjoining to the basis and containing particles of Al2O3 or silicon carbide plus acryl polymer and providing resistance to abrasive wear. Technical result is increased wear- and chemical resistance of flaked elements from natural or conglomerate materials. The invention «Fine organic suspension of carbon metal-containing nanostructures and the method to produce it (RU 2515858» is referred to the area of physical and colloid chemistry and can be used to obtain polymer compositions. Fine organic suspension of carbon metal-containing nanostructures is produced by interaction between nanostructures and polyethylenepolyamine. At first the powder of carbon metalcontaining nanostructures (which are nanoparticles of 3d-metal such as copper, cobalt, nickel stabilized in carbon nanostructures is mechanically milled, then it is mechanically ground with polyethylenepolyamine introduced portionally unless and until the content of nanostructures is less 1 g/ml. The invention results in decreased power inputs as the obtained fine organic suspension of carbon and metal-containing nanostructures is able to recover due to

  2. Resistance to Abrasive Wear and Volume Fraction of Carbides in Cast High-manganese Austenitic Steel with Composite Structure

    Directory of Open Access Journals (Sweden)

    Tęcza G.

    2015-12-01

    Full Text Available Cast Hadfield steel is characterised by high abrasion resistance, provided, however, that it is exposed to the effect of dynamic loads. During abrasion without loading, e.g. under the impact of loose sand jet, its wear resistance drops very drastically. To increase the abrasion resistance of this alloy under the conditions where no pressure is acting, primary vanadium carbides are formed in the metallurgical process, to obtain a composite structure after the melt solidification. The primary, very hard, carbides uniformly distributed in the austenitic matrix are reported to double the wear resistance of samples subjected to the effect of a silicon carbide-water mixture.

  3. Wear resistance of a modified polymethyl methacrylate artificial tooth compared to five commercially available artificial tooth materials.

    Science.gov (United States)

    Kamonwanon, Pranithida; Yodmongkol, Sirasa; Chantarachindawong, Rojcharin; Thaweeboon, Sroisiri; Thaweeboon, Boonyanit; Srikhirin, Toemsak

    2015-08-01

    Wear resistance is a limitation of artificial denture teeth. Improving the wear resistance of conventional artificial denture teeth is of value to prosthodontic patients. The purpose of this in vitro study was to evaluate the wear resistance and hardness of modified polymethyl methacrylate artificial denture teeth compared to 5 commercially available artificial tooth materials. This study evaluated 180 artificial denture teeth (6 groups) that included 3 groups of conventional artificial teeth (MajorDent, Cosmo HXL, and Gnathostar), 2 groups of composite resin artificial teeth (Endura and SR Orthosit PE), and 1 group of modified surface artificial teeth. The flattened buccal surface of each tooth (n=15) was prepared for investigation with the Vickers hardness test and the elucidate wear test (n=15) by using a brushing machine. Each group was loaded for 18,000 cycles, at 2 N, and 150 rpm. The wear value was identified with a profilometer. The data were statistically analyzed by using 1-way ANOVA and post hoc Turkey honestly significant difference tests (α=.001). The tribologies were observed under a scanning electron microscope, and the cytotoxicities were evaluated by MTT assay. The Vickers hardnesses ranged from 28.48 to 39.36. The wear depths and worn surface area values ranged from 1.12 to 10.79 μm and from 6.74 to 161.95 μm(2). The data revealed that the modified artificial denture teeth were significantly harder and exhibited significantly higher wear resistance than did the conventional artificial teeth (Pmaterial. Within the limitations of this study, the polymethyl methacrylate modified surface artificial denture teeth was not significantly different from that of the composite resin artificial denture teeth, with the exceptions that the surface was harder and more wear resistant. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  4. The Use of Nitriding to Enhance Wear Resistance of Cast Irons and 4140 Steel

    Science.gov (United States)

    Yang, Zaidao

    This research is focused on using nitriding to enhance the wear resistance of austempered ductile iron (ADI), ductile iron (DI), and gray iron (GI), and 4140 steel. Three gas nitriding processes, namely "Gas nitriding + nitrogen cooled down to 800°F (Blue)", "Gas nitriding + cooled down to 300°F (Gray)", and "Gas nitriding + oil quenched (Oil)" were used for the cast irons. Three salt bath nitriding processes, namely Isonite, QP (Quench, Polish) and QPQ (Quench, Polish, Quench) were used for the 4140 steel. This study was carried out through optical metallography, roughness measurements, microhardness, and SEM. The ball-on-disc wear tests were conducted under lubricated conditions. It was found that COF for all materials in all nitrided conditions was small (Gray and Oil gas nitriding processes. For the 4140 steel, The surface microhardness of the ISONITE specimen was around 1400HV. QP and QPQ processes produce a surface microhardness of 2000-2200HV, which suggests that they may show improved wear behaviour compared to ISONITE- treated steels.

  5. Forecast of reliability for mechanical components subjected to wearing; Pronostico de la fiabilidad de componentes mecanicos sometidos a desgaste

    Energy Technology Data Exchange (ETDEWEB)

    Angulo-Zevallos, J.; Castellote-Varona, C.; Alanbari, M.

    2010-07-01

    Generally, improving quality and price of products, obtaining a complete customer satisfaction and achieving excellence in all the processes are some of the challenges currently set up by every company. To do this, knowing frequently the reliability of some component is necessary. To achieve this goal, a research, that contributes with clear ideas and offers a methodology for the assessment of the parameters involved in the reliability calculation, becomes necessary. A parameter closely related to this concept is the probability of product failure depending on the operating time. It is known that mechanical components fail by: creep, fatigue, wear, corrosion, etc. This article proposes a methodology for finding the reliability of a component subject to wear, such as brake pads, grinding wheels, brake linings of clutch discs, etc. (Author)

  6. Corrosion failure of Ni-resist pumping system components

    Energy Technology Data Exchange (ETDEWEB)

    Tatarov, A.; Gareau, F. [Skystone Engineering, Calgary, AB (Canada); Bondarchuk, D.; Cymbol, B. [Apache Canada Ltd., Calgary, AB (Canada)

    2010-07-01

    This paper discussed a failure analysis conducted after the failure of a new high pressure horizontal pumping system that was installed as part of an oilfield injection system. The pump impellers failed after less than a year in service due to the corrosion and cracking. The components were constructed from Ni-Resist type 1, a commonly used material in corrosive environments, as well as a polytetrafluoroethylene (PTFE) surface coating. A visual examination, X-ray diffraction, optical microscopy, scanning electron microscopy (SEM) and a metallographic examination did not demonstrate signs of impingement corrosion, abrasive wear, or cavitation. Results of the study showed that the root cause of the corrosion failure was the permeability of the coating, and the unprotected surfaces of the Ni-Resist material, which did not have a protective passive film. The system was found to contain an un-removed surface scale of sand and ceramics as well as materials left over from the manufacturing process. A thorough cleaning of the system's surfaces would have allowed a passive layer to form on the surface and prevented the failure from occurring. 2 refs., 5 figs.

  7. Effects of heat treatment on properties of multi-element low alloy wear-resistant steel

    Directory of Open Access Journals (Sweden)

    SONG Xu-ding

    2007-02-01

    Full Text Available The paper has studied the mechanical properties and heat treatment effects on multi-element low alloy wear-resistant steel (MLAWS used as a material for the liner of rolling mill torii. The results show that when quenched at 900-920℃ and tempered at 350-370℃, the MLAWS has achieved hardness above 60 HRC, tensile strength greater than 1 600 MPa, impact toughness higher than 18J/cm2 and fracture toughness greater than 37 MPa

  8. Microstructure and Abrasive Wear Resistance of 18Cr-4Ni-2.5Mo Cast Steel

    Directory of Open Access Journals (Sweden)

    Kalandyk B.

    2012-12-01

    Full Text Available An influence of a decreased Cr content on the microstructure of the highly alloyed Cr-Ni cast steel, duplex type, melted under laboratory conditions, was characterized in the paper. The microstructure investigations were performed in the initial state and after the heat treatment (solution annealing at 1060°C as well as the phase transformation kinetics at continuous cooling was measured. The wear resistance of the investigated cast steel was tested and compared with the 24%Cr-5%Ni-2.5%Mo cast steel.

  9. Restoration of the wear-resistant coatings on a GTE compressor airfoil shroud platform

    Science.gov (United States)

    Abraimov, N. V.; Geikin, V. A.; Chekalova, E. A.; Lukina, V. V.

    2017-06-01

    The deposition of a VT20 alloy onto the airfoil shroud platform of a compressor in an argon atmosphere and the composition, the structure, and the properties of a restored wear-resistant VK-25M coating are studied. The coating deposited onto the built-up material is found to contain (%) 3-4 C, 72-74 W, and 23-24 Co. This coating does not undergo cracking when a diamond pyramid is indented at a load of 50 kg or a diamond cone is indented at a load of 100 kg at a layer thickness of 0.15, 0.25, and 0.38 mm.

  10. Laser clad NiCrBSi alloy wear-resistance coating with RE addition on heavy duty spur gear flank

    Science.gov (United States)

    Zhao, N.; Tao, L.; Guo, H.; Zhang, M. Q.

    2017-10-01

    In this research the wear-resistance composite coating successfully produced on heavy duty gear work surface by laser was reported. The coating containing 99 wt.% NiCrBSi alloy and 1 wt.% RE (rare earth element) oxidation powder. The RE addition coupled with laser operating parameters optimization caused elimination of both cracks and pores meanwhile further enhanced comprehensive properties of the laser layer. The coating microhardness, microstructure, phase construction and wear behaviors were tested by hardness tester, SEM equipped with EDS, XRD and tribometer, respectively. The results reflected the fact that the RE addition enhanced the coating ability of wear resistance and laser clad layer properly bonded with the gear flank. The wear volume loss rate of coating was half of that of the gear flank metal the COF curve of coating kept bellow that of the gear flank steel.

  11. Effect of Cobalt on Microstructure and Wear Resistance of Ni-Based Alloy Coating Fabricated by Laser Cladding

    Directory of Open Access Journals (Sweden)

    Kaiming Wang

    2017-12-01

    Full Text Available Ni-based alloy powders with different contents of cobalt (Co have been deposited on a 42CrMo steel substrate surface using a fiber laser. The effects of Co content on the microstructure, composition, hardness, and wear properties of the claddings were studied by scanning electron microscopy (SEM, an electron probe microanalyzer (EPMA, X-ray diffraction (XRD, a hardness tester, and a wear tester. The results show that the phases in the cladding layers are mainly γ, M7(C, B3, M23(C, B6, and M2B. With the increase in Co content, the amounts of M7(C, B3, M23(C, B6, and M2B gradually decrease, and the width of the eutectic structure in the cladding layer also gradually decreases. The microhardness decreases but the wear resistance of the cladding layer gradually improves with the increase of Co content. The wear resistance of the NiCo30 cladding layer is 3.6 times that of the NiCo00 cladding layer. With the increase of Co content, the wear mechanism of the cladding layer is changed from abrasive wear to adhesive wear.

  12. Increasing in the wear resistance of injection molds made of 1.2343 steel using Ti/TiN/TiCN/nc-TiCN:a-C/nc-TiC:a-C/a-C nanocomposite coating

    Science.gov (United States)

    Rupetsov, Velko; Mishev, Georgi; Dishliev, Stefan; Kopanov, Viktor; Chitanov, Vassiliy; Kolaklieva, Lilyana; Pashinski, Chavdar

    2017-02-01

    Injection molds used in production of plastic components are subject of heavy abrasion wear. The increase of their wear resistance significantly reduces the production cost. In the current work are presented research results of the wear resistance of injection molds made of steel 1.2343, coated with Ti/TiN/TiCN/nc-TiCN: a-C/nc-TiC:a -C/a-C. The study of the wear rate was done using the volumetric method and the influence of the trace length was investigated. The coating thickness, nanohardness, elastic modulus and adhesion were also tested. The coating was applied on unhardened ground specimens, hardened ground specimens and hardened polished specimens.

  13. Effects of Rare Earth Metal Addition on Wear Resistance of Chromium-Molybdenum Cast Steel

    Directory of Open Access Journals (Sweden)

    Kasinska J.

    2017-09-01

    Full Text Available This paper discusses changes in the microstructure and abrasive wear resistance of G17CrMo5-5 cast steel modified with rare earth metals (REM. The changes were assessed using scanning microscopy. The wear response was determined in the Miller test to ASTM G75. Abrasion tests were supplemented with the surface profile measurements of non-modified and modified cast steel using a Talysurf CCI optical profilometer. It was demonstrated that the modification substantially affected the microstructure of the alloy, leading to grain size reduction and changed morphology of non-metallic inclusions. The observed changes in the microstructure resulted in a three times higher impact strength (from 33 to 99 kJ/cm2 and more than two times higher resistance to cracking (from 116 to 250 MPa. The following surface parameters were computed: Sa: Arithmetic mean deviation of the surface, Sq: Root-mean-square deviation of the surface, Sp: Maximum height of the peak Sv: Maximum depth of the valley, Sz: Ten Point Average, Ssk: Asymmetry of the surface, Sku: Kurtosis of the surface. The findings also indicated that the addition of rare earth metals had a positive effect on the abrasion behaviour of G17CrMo5-5 cast steel.

  14. Mesenchymal stem cell interaction with ultra-smooth nanostructured diamond for wear-resistant orthopaedic implants.

    Science.gov (United States)

    Clem, William C; Chowdhury, Shafiul; Catledge, Shane A; Weimer, Jeffrey J; Shaikh, Faheem M; Hennessy, Kristin M; Konovalov, Valery V; Hill, Michael R; Waterfeld, Alfred; Bellis, Susan L; Vohra, Yogesh K

    2008-01-01

    Ultra-smooth nanostructured diamond (USND) can be applied to greatly increase the wear resistance of orthopaedic implants over conventional designs. Herein we describe surface modification techniques and cytocompatibility studies performed on this new material. We report that hydrogen (H)-terminated USND surfaces supported robust mesenchymal stem cell (MSC) adhesion and survival, while oxygen- (O) and fluorine (F)-terminated surfaces resisted cell adhesion, indicating that USND can be modified to either promote or prevent cell/biomaterial interactions. Given the favorable cell response to H-terminated USND, this material was further compared with two commonly used biocompatible metals, titanium alloy (Ti-6Al-4V) and cobalt chrome (CoCrMo). MSC adhesion and proliferation were significantly improved on USND compared with CoCrMo, although cell adhesion was greatest on Ti-6Al-4V. Comparable amounts of the pro-adhesive protein, fibronectin, were deposited from serum on the three substrates. Finally, MSCs were induced to undergo osteoblastic differentiation on the three materials, and deposition of a mineralized matrix was quantified. Similar amounts of mineral were deposited onto USND and CoCrMo, whereas mineral deposition was slightly higher on Ti-6Al-4V. When coupled with recently published wear studies, these in vitro results suggest that USND has the potential to reduce debris particle release from orthopaedic implants without compromising osseointegration.

  15. Mesenchymal stem cell interaction with ultra smooth nanostructured diamond for wear resistant orthopaedic implants

    Science.gov (United States)

    Clem, William C.; Chowdhury, Shafiul; Catledge, Shane A.; Weimer, Jeffrey J.; Shaikh, Faheem M.; Hennessy, Kristin M.; Konovalov, Valery V.; Hill, Michael R.; Waterfeld, Alfred; Bellis, Susan L.; Vohra, Yogesh K.

    2008-01-01

    Ultra smooth nanostructured diamond (USND) can be applied to greatly increase the wear resistance of orthopaedic implants over conventional designs. Herein we describe surface modification techniques and cytocompatibility studies performed on this new material. We report that hydrogen (H) -terminated USND surfaces supported robust mesenchymal stem cell (MSC) adhesion and survival, while oxygen (O) and fluorine (F) -terminated surfaces resisted cell adhesion, indicating that USND can be modified to either promote or prevent cell/biomaterial interactions. Given the favorable cell response to H-terminated USND, this material was further compared with two commonly-used biocompatible metals, titanium alloy (Ti-6Al-4V) and cobalt chrome (CoCrMo). MSC adhesion and proliferation were significantly improved on USND compared with CoCrMo, although cell adhesion was greatest on Ti-6Al-4V. Comparable amounts of the proadhesive protein, fibronectin, were deposited from serum on the three substrates. Finally, MSCs were induced to undergo osteoblastic differentiation on the three materials, and deposition of a mineralized matrix was quantified. Similar amounts of mineral were deposited onto USND and CoCrMo, whereas mineral deposition was slightly higher on Ti-6Al-4V. When coupled with recently published wear studies, these in vitro results suggest that USND has the potential to reduce debris particle release from orthopaedic implants without compromising osseointegration. PMID:18490051

  16. Self-lubricating, wear resistant protic ionic liquid-epoxy resin

    Directory of Open Access Journals (Sweden)

    M. D. Aviles

    2017-03-01

    Full Text Available A new self-lubricating, wear resistant epoxy resin material (ER+DCi has been obtained by addition of a 9 wt.% of the room-temperature protic ionic liquid (PIL tri-[bis(2-hydroxyethylammonium] citrate (DCi to the mixture of the prepolymer and the hardener composed of a mixture of amines. The highly polar tricationic protic ammonium carboxylate ionic liquid shows a high contact angle on the resin surface and distributes inside the epoxy matrix as spheres of around 50 µm in diameter, with a mean density of approximately 38 mm2. The presence of the ionic liquid fluid phase inside the cavities has been determined by SEM observation of fracture surfaces and FTIR microscopy. The DCi phase reduces the residual curing enthalpy and the glass transition temperature, as determined by DSC, without significantly changing microhardness or electrical resistivity values. DMA analysis shows that DCi reduces storage modulus, loss modulus and tan δ values. The tribological performance of the new material has been compared with that of the neat epoxy resin under pin-on-disc sliding conditions. ER+DCi shows more than 50% reduction of the friction coefficient with respect to neat epoxy resin, and no surface damage, in contrast with the severe wear that takes place in the case of neat epoxy resin. A self-lubrication mechanism by release of the ionic liquid lubricant under load is proposed.

  17. Standard test method for ranking resistance of plastic materials to sliding wear using a block-on-ring configuration

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1997-01-01

    1.1 This test method covers a laboratory procedure to measure the resistance of plastic materials under dry sliding conditions. The test utilizes a block-on-ring geometry to rank materials according to their sliding wear characteristics under various conditions. 1.2 The test specimens are small so that they can be molded or cut from fabricated plastic parts. The test may be run at the load, velocity, and temperature which simulate the service condition. 1.3 Wear test results are reported as specific wear rates calculated from volume loss, sliding distance, and load. Materials with superior wear resistance have lower specific wear rates. 1.4 This test method allows the use of both single- and multi-station apparatus to determine the specific wear rates. 1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibil...

  18. A Study on Wear Resistance of HVOF-Sprayed Ni-MoS2 Self-Lubricating Composite Coatings

    Science.gov (United States)

    Liu, Y. L.; Jeng, M. C.; Hwang, J. R.; Chang, C. H.

    2015-02-01

    Composite coating techniques are becoming increasingly popular owing to their peculiar performances. In this study, the wear resistance of thermally sprayed Ni-MoS2 composite coatings on an AISI 1020 steel substrate was investigated. Ni-MoS2 composite powder (size: 60-90 μm) containing 25 wt.% of dispersed MoS2 was prepared by electroless plating. Ni-MoS2 composite coatings were then prepared by HVOF thermal spraying. The coatings were characterized by structural, surface morphological, and compositional analyses by means of microhardness tests, SEM/EDS, XRD, and ICP-AES. For the evaluation of their anti-wear properties, the composites were subjected to ball-on-disk dry wear tests based on the ASTM G99 standard at room temperature. Experimental results showed that some of the MoS2 content dispersed in the Ni-based composite coating burnt away during the high-temperature spraying process, thereby reducing the MoS2 concentration in the coating. In the wear test, the weight loss in the Ni-MoS2 composite coating was minimal under a low load (30 N). The average wear rate of the coatings was found to be ~1/40 times that of a Ni coating, showing that the wear resistance of the composite coatings was significantly improved by MoS2 addition.

  19. Investigating Corrosion, Wear Resistance and Friction of AA5454-O Series after its Severe Deformation by Rolling

    Directory of Open Access Journals (Sweden)

    Sinan SEZEK

    2017-02-01

    Full Text Available AA5454-O is an easily wrought, or in other words, a ductile aluminium alloy, however, its mechanical properties are inferior as compared to those of other alloys. The change taking place in corrosion resistance of AA5454-O alloy as a result of its severe plastic deformation (SPD by rolling has been investigated in this study. It has been observed that significant changes occurred in abrasion wear and corrosion resistances of AA5454-O alloy, which was severely deformed up to 80 % by rolling process. Corrosion resistance of the alloy that was severely deformed by rolling has increased. The effect of deformation rate on corrosion has been investigated by applying potentiodynamic test whereas on the other hand such change has been evidenced also through corrosion test. It has been observed that friction coefficient of severely deformed AA5454-O alloy varied by around 10 %, and that, associated with such change, its wear resistance also increased considerably. It has been determined that, as a result of severe deformation by rolling, hardness values rose in areas where the alloy was in contact with rolling surface. In this study, wear resistance of severely deformed alloy has been investigated as well. It has been observed that deformation value contributed positively to the increase in wear resistance.DOI: http://dx.doi.org/10.5755/j01.ms.23.1.14650

  20. Effect of Fe2B boride orientation on abrasion wear resistance of Fe-B cast alloy

    Directory of Open Access Journals (Sweden)

    Da-wei Yi

    2017-07-01

    Full Text Available The microstructures and abrasion wear resistance of directional solidification Fe-B alloy have been investigated using optical microscopy, X-ray diffraction, scanning electron microscopy and laser scanning microscopy. The results show that the microstructure of as-cast Fe-B alloy consists of ferrite, pearlite and eutectic boride. After heat treatment, the microstructure is composed of boride and martensite. The plane which is perpendicular to the boride growth direction possesses the highest hardness. In two-body abrasive wear tests, the silicon carbide abrasive can cut the boride and martensite matrix synchronously, and the wear mechanism is micro cutting mechanism. The worn surface roughness and the wear weight loss both increase with the increasing contact load. Moreover, when the boride growth direction is perpendicular to the worn surface, the highest hardness plane of the boride can effectively oppose abrasion, and the martensite matrix can surround and support borides perfectly.

  1. Effect of second phase morphology on wear resistance of Fe-TiC composites

    Directory of Open Access Journals (Sweden)

    A. Rajabi

    2015-03-01

    Full Text Available The aim of this paper is to investigate the influence of the second phase morphology (TiC on wear behavior in Fe-TiC composites. Fe-TiC composites were successfully produced by an in-situ melting method under an inert argon gas in which raw materials, namely cast iron (Fe-3.5wt%C and 10wt%ferrotitanium (Fe-72wt%Ti were used. The obtained melting was centrifugally casted in mold ceramic to produce the samples required. XRD instrument was also used to identify the acquired phases. The size of TiC and hardness of composites were examined by an image analyser and Vickers hardness respectively. Morphological investigation of the microstructure was performed using scanning electron microscopy (SEM. Weight lost was measured under the condition of using a pin-on-wheel configuration with normal load 20N, sliding distance up to 2000m and speed 0.8m/s. The results indicated the wear resistance in re-melt composites improved due to TiC good uniform distribution with its regular form.

  2. Wear Resistance Limited by Step Edge Failure: The Rise and Fall of Graphene as an Atomically Thin Lubricating Material.

    Science.gov (United States)

    Qi, Yizhou; Liu, Jun; Zhang, Ji; Dong, Yalin; Li, Qunyang

    2017-01-11

    Owing to its intrinsically lubricious property, graphene has a high potential to be an atomically thin solid lubricant for sliding interfaces. Despite its ultrahigh breaking strength at the nanoscale, graphene often fails to maintain its integrity when subjected to macroscale tribological tests. To reveal the true wear characteristics of graphene, a nanoscale diamond tip was used to scratch monolayer graphene mechanically exfoliated to SiO2 substrates. Our experimental results show that while graphene exhibited extraordinary wear resistance in the interior region, it could be easily damaged at the step edge under a much lower normal load (∼2 orders of magnitude smaller). Similar behavior with substantially reduced wear resistance at the edge was also observed for monatomic graphene layer on graphite surface. Using molecular dynamics simulations, we attributed this markedly weak wear resistance at the step edge to two primary mechanisms, i.e., atom-by-atom adhesive wear and peel induced rupture. Our findings shed light on the paradox that graphene is nanoscopically strong yet macroscopically weak. As step edge is ubiquitous for two-dimensional materials at the macroscale, our study also provides a guiding direction for maximizing the mechanical and tribological performance of these atomically thin materials.

  3. Influence of Orientations of Bionic Unit Fabricated by Laser Remelting on Fatigue Wear Resistance of Gray Cast Iron

    Science.gov (United States)

    Chen, Zhi-Kai; Zhou, Ti; Zhang, Hai-feng; Yang, Wan-shi; Zhou, Hong

    2015-06-01

    Fatigue wear resistance improvements were researched by studying experimental samples with gray cast iron fabricated with bionic units in different orientations. Experimental samples were modified by laser surface remelting, including parallel, vertical, and gradient units to the wear direction. The remelting pool was then studied to determine the micro-hardness, microstructure, alteration of phase, and etc. Lab-control fatigue wear test method was applied with the treated and untreated samples tested under the laboratorial conditions. Wear resistance result was considered as the rolling contact fatigue (RCF) resistance and mechanisms of the modified samples were experimentally investigated and discussed. Results suggested that all treated samples demonstrated the beneficial effect on the RCF improvement due to lack of graphite and reinforcement of treated region. Results also indicated the sample with fastigiated units was more effective than that with vertical units or parallel units to the wear direction. Influence of the sample unit's angle which intensely depended on the conditions of actual application, however, was not identified.

  4. Wear Resistance of Steels with Surface Nanocrystalline Structure Generated by Mechanical-Pulse Treatment

    Science.gov (United States)

    Nykyforchyn, Hryhoriy; Kyryliv, Volodymyr; Maksymiv, Olha

    2017-02-01

    The influence of the surface mechanical-pulse treatment based on high-speed friction with a rapid cooling by the technological environment on the wear resistance of medium- and high-carbon steels was considered. The treatment due to a severe plastic deformation enabled obtaining the nanocrystalline structure with a grain size of 14-40 nm. A high positive effect of this treatment was obtained not only because of metal nanocrystallization but also thanks to other factors, namely, structural-phase transformations, carbon saturation of the surface due to decomposition of the coolant and the friction coefficient decrease. Higher carbon content leads to better strengthening of the surface, and its microhardness can reach 12 GPa.

  5. Improvements in Microstructure and Wear Resistance of Plasma-Sprayed Fe-Based Amorphous Coating by Laser-Remelting

    Science.gov (United States)

    Jiang, Chaoping; Chen, Hong; Wang, Gui; Chen, Yongnan; Xing, Yazhe; Zhang, Chunhua; Dargusch, Matthew

    2017-04-01

    Amorphous coating technology is an attractive way of taking advantage of the superior properties of amorphous alloys for structural applications. However, the limited bonds between splats within the plasma-sprayed coatings result in a typically lamellar and porous coating structure. To overcome these limitations, the as-sprayed coating was treated by a laser-remelting process. The microstructure and phase composition of two coatings were analyzed using scanning electron microscopy with energy-dispersive spectroscopy, transmission electron microscopy, and x-ray diffraction. The wear resistance of the plasma-sprayed coating and laser-remelted coating was studied comparatively using a pin-on-disc wear test under dry friction conditions. It was revealed that the laser-remelted coating exhibited better wear resistance because of its defect-free and amorphous-nanocrystalline composited structure.

  6. Tribological tests of wear-resistant coatings used in the production of drill bits of horizontal and inclined drilling

    Science.gov (United States)

    Maslov, A. L.; Markova, I. Yu; Zakharova, E. S.; Polushin, N. I.; Laptev, A. I.

    2017-05-01

    It is known that modern drilling bit body undergoes significant abrasive wear in the contact area with the solid and the retracted cuttings. For protection of the body rationally use wear-resistant coating, which is welded directly to the body of bit. Before mass use of the developed coverings they need to be investigated by various methods that it was possible to characterize coatings and on the basis of the obtained data to perform optimization of both composition of coatings and technology. Such methods include microstructural studies tribological tests, crack resistance and others. This work is devoted to the tribological tests of imported brand of coatings WokaDur NiA and and domestic brand of coating HR-6750 (both brands manufactured by Ltd “Oerlikon Metco Rus”), used to protect the bit body from abrasive wear.

  7. Wear Resistance Properties Reinforcement Using Nano-Al/Cu Composite Coating in Sliding Bearing Maintenance.

    Science.gov (United States)

    Liu, Hongtao; Li, Zhixiong; Wang, Jianmei; Sheng, Chenxing; Liu, Wanli

    2018-03-01

    Sliding bearing maintenance is crucial for reducing the cost and extending the service life. An efficient and practical solution is to coat a restorative agent onto the worn/damaged bearings. Traditional pure-copper (Cu) coating results in a soft surface and poor abrasion resistance. To address this issue, this paper presents a nano-composite repairing coating method. A series of nano-Al/Cu coatings were prepared on the surface of 45 steel by composite electro-brush plating (EBP). Their micro-hardness was examined by a MHV-2000 Vickers hardness tester, and tribological properties by a UMT-2M Micro-friction tester, 3D profiler and SEM. Then, the influence of processing parameters such as nano-particle concentration and coating thickness on the micro-hardness of nano-Al/Cu coating was analyzed. The experimental analysis results demonstrate that, when the nano-Al particle concentration in electrolyte was 10 g/L, the micro-hardness of the composite coating was 1.1 times as much as that of pure-Cu coating. When the Al nano-particle concentration in electrolyte was 20 g/L, the micro-hardness of the composite coating reached its maximum value (i.e., 231.6 HV). Compared with the pure-Cu coating, the hardness and wear resistance of the nano-composite coating were increased, and the friction coefficient and wear volume were decreased, because of the grain strengthening and dispersion strengthening. The development in this work may provide a feasible and effective nano-composite EBP method for sliding bearing repair.

  8. Ultrathin wear-resistant coatings for the tape bearing surface of thin-film magnetic heads for digital compact cassette

    Science.gov (United States)

    Zieren, V.; Dejongh, M.; Vangroenou, A. Broese; Vanzon, J. B. A.; Lasinski, P.; Theunissen, G. S. A. M.

    1994-03-01

    The introduction of the digital compact cassette (DCC) system into the consumer market imposed some severe requirements on the durability of the thin-film heads used in this system. The reliability of the head's record and playback functions has to be maintained under a wide variety of climatic conditions and tape types, as a consequence of the system's backward compatibility with the analog compact cassette. This paper describes the results of several accelerated wear tests as well as of durability tests against tape, which were set-up to find the best material and process conditions for a wear-resistant coating on the tape bearing surface of a DCC head. This ultrathin coating (less than 75 nm) appeared to be the best solution as a safeguard against severe pole-tip recession, which would cause an unacceptable distance loss in the recording system. The first material which showed a very high wear resistance was CrN. As CrN fulfils all requirements for wear and corrosion resistance in the home application, this material is presently used in all DCC home decks. However, under extremely abrasive conditions, such as may be encountered in a car environment (e.g. cold start at -20 C), CrN is surpassed by an even more wear-resistant material, called SPL (super protective layer). Therefore, SPL is preferred as a coating on thin-film heads for car stereo (as well as portable) DCC apparatus. Both materials are characterized by their specific wear performance, which has a superior impact on the electrical (record and playback) properties of the head during its lifetime.

  9. EFECT OF PLASMA IMMERSION ION IMPLANTATION TREATEMENT IN THE WEAR RESISTANCE OF Ti-6Al-4V ALLOY

    Directory of Open Access Journals (Sweden)

    Zepka, Susana

    2015-07-01

    Full Text Available The objective of this work was the evaluation of wear resistance of Ti-6Al-4V alloy after plasma immersion ion implantation (PIII in different immersion times. The goal of this process was the modification of surface properties of the alloy to obtain better tribology properties. In this process, atoms can be injected on the material´s surface changing the mechanical properties in the region near the surface independently of thermodynamics variables, as solubility and difusivity. The samples were submitted to 120 e 180 minutes of implantation at 250°C in the three samples for each condition. The wear analyses were made by pin-on-disk process, where the lost volumes and wear coefficients were compared in the samples. It was observed the decreasing of attrite coefficient and the lost volume of the material during wear test. The implanted sample by 180 minutes has showed the wear coefficient 35.12% lower in comparison of the sample without treatment, and 11.09% lower in comparison of implanted sample by 120 minutes. It can be observed that the sample implanted by 180 minutes showed lower wear coefficient.

  10. Retrieved Unicompartmental Implants with Full PE Tibial Components: The Effects of Knee Alignment and Polyethylene Thickness on Creep and Wear

    Science.gov (United States)

    Hernigou, Ph; Poignard, A; Filippini, P; Zilber, S

    2008-01-01

    Creep and true wear of polyethylene are difficult to evaluate on radiographs of knee arthroplasties and for this reason the true rate of polyethylene wear in vivo after unicompartmental arthroplasty is not well known. This study evaluated the creep and true wear in fifty-five medial retrieved unicompartmental implants that had a flat articular surface at the time of implantation. All the full polyethylene tibial components had the same design and were retrieved from eleven to 224 months (mean 152 months) after their implantation. The postoperative varus deformity had been measured on weight-bearing radiographs of the whole limb (hip-knee-ankle angle). The retrieved implants were placed in a coordinate measuring machine and the coordinates of a grid of points were obtained. Using this system, a three dimensional scaled image of the implant could be created and was used to calculate the total penetration of the femoral condyle due to true wear and creep. Total linear penetration rates ranged from 0.18 to 2.6 millimeters per year (mean 0.25 millimeters per year). Linear penetration rates due to true wear ranged from 0.08 to 1.4 millimeters per year (mean 0.13 millimeter per year), and penetration due to creep ranged from 0.07 to 1.9 millimeters per year (mean 0.12 millimeters per year). The linear and volumetric penetration rates of the femoral condyle due to true wear were negatively correlated with the duration of implantation. The linear penetration rate due to creep was higher in the first two years after the implantation compared to the subsequent years. Using multiple linear regression analyses to remove the confounding effects of age, weight, gender and thickness of the implant, we found that an increase of the postoperative varus deformity was due to an increase of creep (p = 0.03) but not with an increase of true wear (p = 0.25). Thinner implants were due to an increase of creep (p = 0.02) but not with an increase of true wear (p = 0.34). Increase in age was

  11. Antibacterial activity, corrosion resistance and wear behavior of spark plasma sintered Ta-5Cu alloy for biomedical applications.

    Science.gov (United States)

    Cui, Jing; Zhao, Liang; Zhu, Weiwei; Wang, Bi; Zhao, Cancan; Fang, Liming; Ren, Fuzeng

    2017-10-01

    Tantalum has been widely used in orthopedic and dental implants. However, the major barrier to the extended use of such medical devices is the possibility of bacterial adhesion to the implant surface which will cause implant-associated infections. To solve this problem, bulk Ta-5Cu alloy has been fabricated by a combination of mechanical alloying and spark plasma sintering. The effect of the addition of Cu on the hardness, antibacterial activity, cytocompatibility, corrosion resistance and wear performance was systematically investigated. The sintered Ta-5Cu alloy shows enhanced antibacterial activity against E. Coli due to the sustained release of Cu ions. However, the addition of Cu would produce slight cytotoxicity and decrease corrosion resistance of Ta. Furthermore, pin-on-disk wear tests show that Ta-5Cu alloy has a much lower coefficient of friction but a higher wear rate and shows a distinct wear mode from that of Ta upon sliding against stainless steel 440C. Wear-induced plastic deformation leads to elongation of Ta and Cu grains along the sliding direction and nanolayered structures were observed upon approaching the sliding surface. The presence of hard oxides also shows a profound effect on the plastic flow of the base material and results in localized vortex patterns. The obtained results are expected to provide deep insights into the development of novel Ta-Cu alloy for biomedical applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Plasma immersion ion implantation on 15-5PH stainless steel: influence on fatigue strength and wear resistance

    Science.gov (United States)

    Bonora, R.; Cioffi, M. O. H.; Voorwald, H. J. C.

    2017-05-01

    Surface improvement in steels is of great interest for applications in industry. The aim of this investigation is to study the effect of nitrogen ion implantation on the axial fatigue strength and wear resistance of 15-5 PH stainless steel. It is well know that electroplated coatings, which are used to improve abrasive wear and corrosion properties, affects negatively the fatigue strength. It is also important to consider requirements to reduce the use of coated materials with electroplated chromium and cadmium, that produce waste, which is harmful to health and environment. The HVOF (High velocity oxygen fuel) process provides hardness, wear strength and higher fatigue resistance in comparison to electroplated chromium. Plasma immersion ion implantation has been used to enhance the hardness, wear, fatigue and corrosion properties of metals and alloys. In the present research the fatigue life increased twice for 15-5 PH three hours PIII treated in comparison to base material. From the abrasive wear tests a lower pin mass reduction was observed, associated to the superficial treatments. The improvement of fatigue and mechanical performance is attributed to a combination of nitrides phase structure and compressive residual stresses during the PIII treatment.

  13. Microstructure Characterization and Wear-Resistant Properties Evaluation of an Intermetallic Composite in Ni-Mo-Si System.

    Science.gov (United States)

    Huang, Boyuan; Song, Chunyan; Liu, Yang; Gui, Yongliang

    2017-02-04

    Intermetallic compounds have been studied for their potential application as structural wear materials or coatings on engineering steels. In the present work, a newly designed intermetallic composite in a Ni-Mo-Si system was fabricated by arc-melting process with commercially pure metal powders as starting materials. The chemical composition of this intermetallic composite is 45Ni-40Mo-15Si (at %), selected according to the ternary alloy diagram. The microstructure was characterized using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS), and the wear-resistant properties at room temperature were evaluated under different wear test conditions. Microstructure characterization showed that the composite has a dense and uniform microstructure. XRD results showed that the intermetallic composite is constituted by a binary intermetallic compound NiMo and a ternary Mo₂Ni₃Si metal silicide phase. Wear test results indicated that the intermetallic composite has an excellent wear-resistance at room-temperature, which is attributed to the high hardness and strong atomic bonding of constituent phases NiMo and Mo₂Ni₃Si.

  14. Lead-free, bronze-based surface layers for wear resistance in axial piston hydraulic pumps

    Energy Technology Data Exchange (ETDEWEB)

    Vetterick, Gregory Alan [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    Concerns regarding the safety of lead have provided sufficient motivation to develop substitute materials for the surface layer on a thrust bearing type component known as a valve plate in axial piston hydraulic pumps that consists of 10% tin, 10% lead, and remainder cooper (in wt. %). A recently developed replacement material, a Cu-10Sn-3Bi (wt.%) P/M bronze, was found to be unsuitable as valve plate surface layer, requiring the development of a new alloy. A comparison of the Cu-1-Sn-10Pb and Cu-10Sn-3Bi powder metal valve plates showed that the differences in wear behavior between the two alloys arose due to the soft phase bismuth in the alloy that is known to cause both solid and liquid metal embrittlement of copper alloys.

  15. Measuring the migration of the components and polyethylene wear after total hip arthroplasty: beads and specialised radiographs are not necessary.

    Science.gov (United States)

    Devane, P A; Horne, J G; Foley, G; Stanley, J

    2017-10-01

    This paper describes the methodology, validation and reliability of a new computer-assisted method which uses models of the patient's bones and the components to measure their migration and polyethylene wear from radiographs after total hip arthroplasty (THA). Models of the patient's acetabular and femoral component obtained from the manufacturer and models of the patient's pelvis and femur built from a single computed tomography (CT) scan, are used by a computer program to measure the migration of the components and the penetration of the femoral head from anteroposterior and lateral radiographs taken at follow-up visits. The program simulates the radiographic setup and matches the position and orientation of the models to outlines of the pelvis, the acetabular and femoral component, and femur on radiographs. Changes in position and orientation reflect the migration of the components and the penetration of the femoral head. Validation was performed using radiographs of phantoms simulating known migration and penetration, and the clinical feasibility of measuring migration was assessed in two patients. Migration of the acetabular and femoral components can be measured with limits of agreement (LOA) of 0.37 mm and 0.33 mm, respectively. Penetration of the femoral head can be measured with LOA of 0.161 mm. The migration of components and polyethylene wear can be measured without needing specialised radiographs. Accurate measurement may allow earlier prediction of failure after THA. Cite this article: Bone Joint J 2017;99-B:1290-7. ©2017 The British Editorial Society of Bone & Joint Surgery.

  16. Evaluation of Skid Resistance of Wearing Course Made Of Stone Mastic Asphalt Mixture in Laboratory Conditions

    Science.gov (United States)

    Wasilewska, Marta

    2017-10-01

    This paper presents the comparison of skid resistance of wearing course made of SMA (Stone Mastic Asphalt) mixtures which differ in resistance to polishing of coarse aggregate. Dolomite, limestone, granite and trachybasalt were taken for investigation. SMA mixtures have the same nominal size of aggregate (11 mm) and very similar aggregate particle-size distribution in mineral mixtures. Tested SMA11 mixtures were designed according to EN 13108-5 and Polish National Specification WT-2: 2014. Evaluation of the skid resistance has been performed using the FAP (Friction After Polishing) test equipment also known as the Wehner/Schulze machine. Laboratory method enables to compare the skid resistance of different types of mixtures under specified conditions simulating polishing processes. Tests were performed on both the specimens made of each coarse aggregate and SMA11 mixtures containing these aggregates. Measuring of friction coefficient μm was conducted before and during polishing process up to 180 0000 passes of polishing head. Comparison of the results showed differences in sensitivity to polishing among particular mixtures which depend on the petrographic properties of rock used to produce aggregate. Limestone and dolomite tend to have a fairly uniform texture with low hardness which makes these rock types susceptible to rapid polishing. This caused lower coefficient of friction for SMA11 mixtures with limestone and dolomite in comparison with other test mixtures. These significant differences were already registered at the beginning of the polishing process. Limestone aggregate had lower value of μm before starting the process than trachybasalt and granite aggregate after its completion. Despite the differences in structure and mineralogical composition between the granite and trachybasalt, slightly different values of the friction coefficient at the end of polishing were obtained. Images of the surface were taken with the optical microscope for better

  17. Accuracy of the SenseWear Armband Mini and the BodyMedia FIT in resistance training.

    Science.gov (United States)

    Reeve, Michael D; Pumpa, Kate L; Ball, Nick

    2014-11-01

    To examine the validity and reliability of the SenseWear Armband Mini and BodyMedia FIT in comparison to the Cosmed K4b(2) portable for assessing energy expenditure during resistance training. Lab based validation and reliability study. Eleven males and 7 females (age = 22.7 ± 4.5 years) completed two resistance-training sessions. Total energy expenditure was simultaneously assessed by the SenseWear Armband Mini, BodyMedia FIT and Cosmed K4b(2) portable. The resistance-training sessions involved 3 sets of 10 repetitions for 9 different exercises. The weight lifted was 70% of the participants 1 repetition max with 90-s rest intervals. Validity and re-test reliability was assessed using Pearson correlations and mean change (%) ± 90% confidence limits and log transformed typical error measurements (TEMCV%). A very large correlation was identified for total energy expenditure (Kcal) from both the SenseWear Armband Mini and BodyMedia FIT in comparison to the Cosmed K4b(2) portable (r = 0.77 and r = 0.78, respectively) and an almost perfect correlation was observed for total energy expenditure (Kcal) between the SenseWear Armband Mini and BodyMedia FIT (r = 0.97). A small percent mean change for the SenseWear Armband Mini (23.7%) and a trivial percent mean change for the BodyMedia FIT (13.8%) was observed in comparison to the Cosmed K4b(2) portable with a tendency to underestimate total energy expenditure. The SenseWear Armband Mini and BodyMedia FIT displayed an almost perfect correlation for total energy expenditure (Kcal) between sessions (r = 0.96 and r = 0.97, respectively) whilst TEMCV% of 5.1 and 4.3, respectively were observed. The SenseWear Armband Mini and BodyMedia FIT provide a valid and reliable measure of energy expenditure during resistance training. There was no significant difference in validity or reliability observed between the SenseWear Armband Mini and BodyMedia FIT. Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All

  18. Effect of molybdenum on wear resistance of Cr-Nb hard-faced S355JR steel

    Energy Technology Data Exchange (ETDEWEB)

    Thongchitrugsa, Nut; Chianpairot, Amnuaysak; Hartung, Fritz; Lothongkum, Gobboon [Chulalongkorn Univ., Bangkok (Thailand). Dept. of Metallurgical Engineering

    2014-03-01

    The effect of Mo on the abrasive wear resistance of (20-23)Cr-(7-8)Nb hard-faced S355JR steel by shielded metal arc welding (SMAW) was studied. Four types of flux, consisting of fixed Cr and Nb but varying Mo contents, coated on hard-facing electrode were used. Microstructure, micro hardness, and abrasive wear resistance of the hard-faced surface were investigated by ASTM G65 D procedure. The original microstructures consist of the primary coarse and eutectic carbides. Mo affects morphology of carbides by decreasing primary carbide size. When Mo content in the hard-faced surface was up to 6.43 wt.-%, the highest abrasive wear resistance and micro hardness were obtained. The decrease of primary carbide size is attributed to the increased nucleation induced by Mo addition. Network structure was observed when the Mo content reaches 10.19 wt.-%. The main mechanisms of wear are micro-cutting and carbide pulling out. (orig.)

  19. Research on microstructure and wear resistance of coatings obtained by adding nanoparticles of refractory compounds in laser cladding

    Science.gov (United States)

    Murzakov, M. A.; Chirikov, S. N.; Markushov, Y. V.

    2016-09-01

    The paper is aimed at research of coatings, which are achieved by means of laser cladding with additives of nanoparticles of high-melting compounds in form of tungsten carbide and tantalum (WC and TaC). In the course of experiment, various ceramic powder concentrations were tested. Main technological characteristics were determined. Power density amounted to 0.68-0.98 MW/cm2. During the coating wear resistance measurement, it was discovered that increase in nanopowder concentration extended wear resistance of coating 2-6 times. Wear resistance measurement and wear coefficient calculation were performed using Brinell-Howarth method. The load was 15 N, load time was 10 minutes. Optical metallographic microscope Neophot-30 was used to study microstructure of the deposited coatings. To reveal microstructure of the deposited coatings, the samples were exposed to chemical etching. Elemental composition of the samples was determined by the methods of X- ray microanalysis in testing solution using electron microscope EVO-50 under acceleration voltage 10-20 kV (probe current 5-50 nA) using energy- and wavelength-dispersive spectrometers.

  20. Non-Magnetic, Tough, Corrosion- and Wear-Resistant Knives From Bulk Metallic Glasses and Composites

    Science.gov (United States)

    Hoffman, Douglas C.; Potter, Benjamin

    2013-01-01

    Quality knives are typically fabricated from high-strength steel alloys. Depending on the application, there are different requirements for mechanical and physical properties that cause problems for steel alloys. For example, diver's knives are generally used in salt water, which causes rust in steel knives. Titanium diver's knives are a popular alternative due to their salt water corrosion resistance, but are too soft to maintain a sharp cutting edge. Steel knives are also magnetic, which is undesirable for military applications where the knives are used as a tactical tool for diffusing magnetic mines. Steel is also significantly denser than titanium (8 g/cu cm vs. 4.5 g/cu cm), which results in heavier knives for the same size. Steel is hard and wear-resistant, compared with titanium, and can keep a sharp edge during service. A major drawback of both steel and titanium knives is that they must be ground or machined into the final knife shape from a billet. Since most knives have a mirrored surface and a complex shape, manufacturing them is complex. It would be more desirable if the knife could be cast into a net or near-net shape in a single step. The solution to the deficiencies of titanium, steel, and ceramic knives is to fabricate them using bulk metallic glasses (or composites). These alloys can be cast into net or near-net shaped knives with a combination of properties that exceed both titanium and steel. A commercially viable BMG (bulk metallic glass) or composite knife is one that exhibits one or all of the following properties: It is based on titanium, has a self-sharpening edge, can retain an edge during service, is hard, is non-magnetic, is corrosion-resistant against a variety of corrosive environments, is tough (to allow for prying), can be cast into a net-shape with a mirror finish and a complex shape, has excellent wear resistance, and is low-density. These properties can be achieved in BMG and composites through alloy chemistry and processing. For

  1. Can Pin-on-Disk Testing Be Used to Assess the Wear Performance of Retrieved UHMWPE Components for Total Joint Arthroplasty?

    Directory of Open Access Journals (Sweden)

    Steven M. Kurtz

    2014-01-01

    Full Text Available The objective of this study was to assess the suitability of using multidirectional pin-on-disk (POD testing to characterize wear behavior of retrieved ultrahigh molecular weight polyethylene (UHMWPE. The POD wear behavior of 25 UHMWPE components, retrieved after 10 years in vivo, was compared with 25 that were shelf aged for 10–15 years in their original packaging. Components were gamma sterilized (25–40 kGy in an air or reduced oxygen (inert package. 9 mm diameter pins were fabricated from each component and evaluated against CoCr disks using a super-CTPOD with 100 stations under physiologically relevant, multidirectional loading conditions. Bovine serum (20 g/L protein concentration was used as lubricant. Volumetric wear rates were found to vary based on the aging environment, as well as sterilization environment. Volumetric wear rates were the lowest for the pins in the gamma inert, shelf aged cohort. These results support the utility of using modern, multidirectional POD testing with a physiologic lubricant as a novel method for evaluating wear properties of retrieved UHMWPE components. The data also supported the hypothesis that wear rates of gamma-inert liners were lower than gamma-air liners for both retrieved and shelf aging conditions. However, this difference was not statistically significant for the retrieved condition.

  2. Enhancement of the wear resistance and microhardness of aluminum alloy by Nd:YaG laser treatment.

    Science.gov (United States)

    Hussein, Haitham T; Kadhim, Abdulhadi; Al-Amiery, Ahmed A; Kadhum, Abdul Amir H; Mohamad, Abu Bakar

    2014-01-01

    Influence of laser treatment on mechanical properties, wear resistance, and Vickers hardness of aluminum alloy was studied. The specimens were treated by using Nd:YaG laser of energy 780 mj, wavelength 512 nm, and duration time 8 ns. The wear behavior of the specimens was studied for all specimens before and after treatment by Nd:YaG laser and the dry wear experiments were carried out by sing pinon-disc technique. The specimens were machined as a disk with diameter of 25 mm and circular groove in depth of 3 mm. All specimens were conducted by scanning electron microscopy (SEM), energy-dispersive X-ray fluorescence analysis (EDS), optical microscopy, and Vickers hardness. The results showed that the dry wear rate was decreased after laser hardening and increased Vickers hardness values by ratio of 2.4:1. The results showed that the values of wear rate for samples having circular grooves are less than samples without grooves after laser treatment.

  3. The study of microstructure of wear-resistant coatings applied for protection from abrasive wear of horizontal and tilt drilling drill bits

    Science.gov (United States)

    Markova, I. Yu; Zakharova, E. S.; Maslov, A. L.; Polushin, N. I.; Laptev, A. I.; SOvchinnikova, M.

    2017-05-01

    Drill bits of the cutting type over the period of their existence have undergone significant changes - from the use of carbide cutters to diamond composite PDC elements, in which the diamond layer is applied to a hardmetal substrate. Using such elements, it was possible to significantly increase the service life of the drill bits, however, during work, there is a significant abrasive deterioration of the bit body, which does not fully realize the advantages of PDC elements. Therefore, to protect the body from wear use special wear-resistant coatings. This work is devoted to research of microstructural coatings, namely coatings brands WokaDur NiA, HR-6750, HR-6750 with sublayer Rock Dur 47 on various steel substrates which applied by the gas-thermal spraying in Ltd “Oerlikon Metko Rus”. They were examined with the use of scanning electron microscopy, X-ray phase analysis and a Vickers micro-hardness tester. It was established that the microhardness of the coating matrix is 590-660 HV, and the microhardness of tungsten carbide particles reinforcing the coating, is 2145-2455 HV.

  4. Facile and scalable preparation of highly wear-resistance superhydrophobic surface on wood substrates using silica nanoparticles modified by VTES

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Shanshan; Liu, Ming [College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004 (China); Wu, Yiqiang, E-mail: wuyq0506@126.com [College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004 (China); Hunan Provincial Collaborative Innovation Center for High-efficiency Utilization of Wood and Bamboo Resources, Central South University of Forestry and Technology, Changsha 410004 (China); Luo, Sha [College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004 (China); Qing, Yan, E-mail: qingyan0429@163.com [College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004 (China); Hunan Provincial Collaborative Innovation Center for High-efficiency Utilization of Wood and Bamboo Resources, Central South University of Forestry and Technology, Changsha 410004 (China); Chen, Haibo [College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004 (China)

    2016-11-15

    Graphical abstract: Highly wear-resistance superhydrophobic surface on wood substrates was fabricated using silica nanoparticles modified by VTES. Display Omitted - Highlights: • Superhydrophobic surface on wood substrates was efficiently fabricated using nanoparticles modified by VTES. • The superhydrophobic surface exhibited a CA of 154° and a SAclose to 0°. • The superhydrophobic surface showed a durable and robust wear-resistance performance. - Abstract: In this study, an efficient, facile method has been developed for fabricating superhydrophobic surfaces on wood substrates using silica nanoparticles modified by VTES. The as-prepared superhydrophobic wood surface had a water contact angle of 154° and water slide angle close to 0°. Simultaneously, this superhydrophobic wood showed highly durable and robust wear resistance when having undergone a long period of sandpaper abrasion or being scratched by a knife. Even under extreme conditions of boiling water, the superhydrophobicity of the as-prepared wood composite was preserved. Characterizations by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy showed that a typical and tough hierarchical micro/nanostructure was created on the wood substrate and vinyltriethoxysilane contributed to preventing the agglomeration of silica nanoparticles and serving as low-surface-free-energy substances. This superhydrophobic wood was easy to fabricate, mechanically resistant and exhibited long-term stability. Therefore, it is considered to be of significant importance in the industrial production of functional wood, especially for outdoor applications.

  5. Effect of Austenite Transformation on Abrasive Wear and Corrosion Resistance of Spheroidal Ni-Mn-Cu Cast Iron

    Directory of Open Access Journals (Sweden)

    Medyński D.

    2016-09-01

    Full Text Available Within the presented work, the effect of austenite transformation on abrasive wear as well as on rate and nature of corrosive destruction of spheroidal Ni-Mn-Cu cast iron was determined. Cast iron contained: 3.1÷3.4 %C, 2.1÷2.3 %Si, 2.3÷3.3 %Mn, 2.3÷2.5 %Cu and 4.8÷9.3 %Ni. At a higher degree of austenite transformation in the alloys with nickel equivalent below 16.0%, abrasive wear resistance was significantly higher. Examinations of the corrosion resistance were carried out with the use of gravimetric and potentiodynamic method. It was shown that higher degree of austenite transformation results in significantly higher abrasive wear resistance and slightly higher corrosion rate, as determined by the gravimetric method. However, results of potentiodynamic examinations showed creation of a smaller number of deep pinholes, which is a favourable phenomenon from the viewpoint of corrosion resistance.

  6. Study on wear resistant cast B-containing 1Cr18Ni9Ti stainless steel

    Directory of Open Access Journals (Sweden)

    Kuang Jiacai

    2009-02-01

    Full Text Available The developed 1Cr18Ni9Ti austenitic stainless steel containing 1.63 wt.%B have been characterized by X-ray diffraction (XRD, electron probe microanalyzer (EPMA, optical microscopy (OM, scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDS and Vickers microhardness measurement. The microstructural evolution and property of high boron stainless steel after solution treatment at the temperature of 1050℃ are also investigated. The results show that the main compositions of borides are Fe, Cr and B, and with small amount of Ni, Mn and C elements. Silicon is insoluble in the borides. The hardness of borides is over 1,500 HV. It has been found that borides do not decompose during solution treatment, but part of borides dissolves into the matrix. The effect of increasing the solubility of boron element in the austenitic matrix favours the hardness enhancement by 8.54%. High boron stainless steel has excellent wear resistance in corrosive environment. Lifetime of transfer pipe made of high boron-containing stainless steel is 1.5-1.8 times longer than that of boron-free 1Cr18Ni9Ti stainless steel.

  7. Enhancement of wear and corrosion resistance of beta titanium alloy by laser gas alloying with nitrogen

    DEFF Research Database (Denmark)

    Chan, Chi-Wai; Lee, Seunghwan; Smith, Graham

    2016-01-01

    be resolved before commercialising in the orthopaedic market. In this work, a newly developed laser surface treatment technique was employed to improve the surface properties of Ti-35.3Nb-7.3Zr-5.7Ta alloy. The surface structure and composition of the laser-treated TNZT surface were examined by grazing......The relatively high elastic modulus coupled with the presence of toxic vanadium (V) in Ti6Al4V alloy has long been a concern in orthopaedic applications. To solve the problem, a variety of non-toxic and low modulus beta-titanium (beta-Ti) alloys have been developed. Among the beta-Ti alloy family......, the quaternary Ti-Nb-Zr-Ta (TNZT) alloys have received the highest attention as a promising replacement for Ti6Al4V due to their lower elastic modulus and outstanding long term stability against corrosion in biological environments. However, the inferior wear resistance of TNZT is still a problem that must...

  8. Investigation of Parent Austenite Grains from Martensite Structure Using EBSD in a Wear Resistant Steel.

    Science.gov (United States)

    Gyhlesten Back, Jessica; Engberg, Göran

    2017-04-26

    Crystallographic reconstruction of parent austenite grain boundaries from the martensitic microstructure in a wear resistant steel was carried out using electron backscattered diffraction (EBSD). The present study mainly aims to investigate the parent austenite grains from the martensitic structure in an as-rolled (reference) steel sample and samples obtained by quenching at different cooling rates with corresponding dilatometry. Subsequently, this study is to correlate the nearest cooling rate by the dilatometer which yields a similar orientation relationship and substructure as the reference sample. The Kurdjumov-Sachs orientation relationship was used to reconstruct the parent austenite grain boundaries from the martensite boundaries in both reference and dilatometric samples using EBSD crystallographic data. The parent austenite grain boundaries were successfully evaluated from the EBSD data and the corresponding grain sizes were measured. The parent austenite grain boundaries of the reference sample match the sample quenched at 100 °C/s (CR100). Also the martensite substructures and crystallographic textures are similar in these two samples. The results from hardness measurements show that the reference sample exhibits higher hardness than the CR100 sample due to the presence of carbides in the reference sample.

  9. Tribaloy intermetallic alloy compositions: new materials or additives for wear resistant applications

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, C.B.; Hoffman, R.A.; Poskitt, R.W.

    1975-01-01

    Properties and uses of TRIBALOY alloys in powder metallurgy fabrication are discussed. Powders of TRIBALOY can be blended with essentially any powder processed by powder metallurgy. Green strength of the blended powder parts is reduced as the amount of TRIBALOY is increased. The concentration of TRIBALOY, however, is usually 15 to 20 volume percent, a compromise between green strength and effectiveness as a wear resistant part. Blended powders are sintered at the temperature normally used for the base metal with special consideration given to a low dew point in the atmosphere. The sintered parts can be coined, carburized, machined, or impregnated in any of the well-known ways. TRIBALOY as a powder blending agent has extended the useful life of P/M parts by factors of 5 and more. A variety of industries are presently using P/M parts at higher temperatures, heavier loads, in poorer or non-lubricated conditions or at higher speeds because of the addition of TRIBALOY. More important, however, is that TRIBALOY can be incorporated in parts to be made by powder metallurgy which until now had not been feasible. The overall effect has been considerable savings for the customer by switching to the powder metal method of manufacturing and increased activity for the fabricator.

  10. Effect of Carbide Ceramic Zone on Wear Resistance of the (Fe,Cr)7C3/Fe Surface Gradient Composite

    Science.gov (United States)

    Ye, Fangxia; Xu, Yunhua; Hojamberdiev, Mirabbos; Lai, Yujun; Wang, Chong; Wang, Xin

    2015-08-01

    In this work, we report on the influence of microstructure and mechanical properties of the (Fe,Cr)7C3 ceramic zone on wear resistance of the (Fe,Cr)7C3/Fe surface gradient composite fabricated by in situ synthesis method followed by a post-heat treatment at 1100 °C for 20 h in argon atmosphere. The phase composition, microstructure, nanoindentation hardness, elastic modulus, fracture toughness, and relative wear resistance of the (Fe,Cr)7C3/Fe surface gradient composite were investigated by means of x-ray diffraction, scanning electron microscopy, nanoindentation tester, and wear resistance testing instrument, respectively. The XRD results showed that (Fe,Cr)7C3 is the predominant crystalline phases in the fabricated composite. The volume fraction of the (Fe,Cr)7C3 particulates formed has a gradient distribution from the surface to the iron matrix, and the microstructure also changes significantly. The (Fe,Cr)7C3 bulk ceramic zone with the volume fraction of about 100% and the (Fe,Cr)7C3 dense ceramic zone with the volume fraction of about 90% were synthesized on the upper surface of the (Fe,Cr)7C3/Fe surface gradient composite, respectively. The average nanoindentation hardness and elastic modulus of the (Fe,Cr)7C3 bulk ceramic zone of the composite were determined to be 12.711 and 256.054 GPa, respectively. The fracture toughness of the (Fe,Cr)7C3 bulk ceramic zone is in the range of 2.06-4.19 MPa m1/2, and its relative wear resistance is about 56 times higher than that of the iron matrix. The (Fe,Cr)7C3 dense ceramic zone with rod-like, secondary (Fe,Cr)7C3 particulates was formed at the bottom of the (Fe,Cr)7C3 bulk ceramic zone. Rod-like, secondary (Fe,Cr)7C3 particulates are dense and grew in the direction of the iron substrate, providing higher wear resistance to the composite. The wear mechanisms of the (Fe,Cr)7C3 bulk and dense ceramic zones are considered to be microcutting, microcracking, and spalling pit.

  11. Application of ceramic coating to improve abrasive wear resistance of die inserts used to press-mould stampings of refractories

    Directory of Open Access Journals (Sweden)

    A. W. Orłowicz

    2017-01-01

    Full Text Available The paper presents results of a study on abrasive wear resistance of die inserts for composite moulds used to pressmould stampings from refractory materials, determined based on susceptibility to scratching with a diamond indenter. For the study, two inserts of high-chromium cast iron were prepared, of which one was provided with a ceramic coating (60 % Al2O3 + 40 % TiO2 with a metallic interlayer (NiAlCrSi. Both layers were deposited by means of the Atmospheric Plasma Spraying (APS method. The obtained scratch test results indicate that with the use of the same load force (20 N, die inserts with ceramic coating are characterized with less indenter penetration depth which should translate to higher resistance to abrasive wear.

  12. Hardness, elastic modulus, and wear resistance of hafnium oxide-based films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Berdova, Maria; Liu, Xuwen; Franssila, Sami, E-mail: sami.franssila@aalto.fi [Department of Materials Science and Engineering, Aalto University, 02150 Espoo (Finland); Wiemer, Claudia; Lamperti, Alessio; Tallarida, Grazia; Cianci, Elena [Laboratorio MDM, IMM CNR, Via C. Olivetti 2, 20864 Agrate Brianza (MB) (Italy); Fanciulli, Marco [Laboratorio MDM, IMM CNR, Via C. Olivetti 2, 20864 Agrate Brianza (MB), Italy and Dipartimento di Scienza dei Materiali, Università degli studi di Milano Bicocca, 20126 Milano (Italy)

    2016-09-15

    The investigation of mechanical properties of atomic layer deposition HfO{sub 2} films is important for implementing these layers in microdevices. The mechanical properties of films change as a function of composition and structure, which accordingly vary with deposition temperature and post-annealing. This work describes elastic modulus, hardness, and wear resistance of as-grown and annealed HfO{sub 2}. From nanoindentation measurements, the elastic modulus and hardness remained relatively stable in the range of 163–165 GPa and 8.3–9.7 GPa as a function of deposition temperature. The annealing of HfO{sub 2} caused significant increase in hardness up to 14.4 GPa due to film crystallization and densification. The structural change also caused increase in the elastic modulus up to 197 GPa. Wear resistance did not change as a function of deposition temperature, but improved upon annealing.

  13. Mechanical And Microstructural Evaluation Of A Wear Resistant Steel; Avaliacao mecanica e microestrutural de um aco resistente ao desgaste

    Energy Technology Data Exchange (ETDEWEB)

    Santos, F.L.F. dos; Vieira, A.G.; Correa, E.C.S.; Pinheiro, I.P., E-mail: falletti@hotmail.co [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET/MG), Belo Horizonte, MG (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    In the present work, the analysis of the mechanical properties and the microstructural features of a high strength low alloy steel, containing chromium, molybdenum and boron, subjected to different heat treatments, was conducted. After austenitizing at 910 deg C for 10 minutes, three operations were carried out: oil quenching, oil quenching followed by tempering at 200 deg C for 120 minutes and austempering at 400 deg C for 5 minutes followed by water cooling. The analysis was performed through tensile and hardness tests, optical microscopy and X-ray diffraction. The bainitic structure led to high strength and toughness, both essential mechanical properties for wear resistant steels. The occurrence of allotriomorphic ferrite and retained austenite in the samples also increased the wear resistance. This phenomenon is related to the fact that both structures are able to be deformed and, in the case of the retained austenite, the transformation induced plasticity TRIP effect may take place as the material is used. (author)

  14. Enhancement of wear and ballistic resistance of armour grade AA7075 aluminium alloy using friction stir processing

    Directory of Open Access Journals (Sweden)

    I. Sudhakar

    2015-03-01

    Full Text Available Industrial applications of aluminium and its alloys are restricted because of their poor tribological properties. Thermal spraying, laser surfacing, electron beam welding are the most widely used techniques to alter the surface morphology of base metal. Preliminary studies reveal that the coating and layering of aluminium alloys with ceramic particles enhance the ballistic resistance. Furthermore, among aluminium alloys, 7075 aluminium alloy exhibits high strength which can be compared to that of steels and has profound applications in the designing of lightweight fortification structures and integrated protection systems. Having limitations such as poor bond integrity, formation of detrimental phases and interfacial reaction between reinforcement and substrate using fusion route to deposit hard particles paves the way to adopt friction stir processing for fabricating surface composites using different sizes of boron carbide particles as reinforcement on armour grade 7075 aluminium alloy as matrix in the present investigation. Wear and ballistic tests were carried out to assess the performance of friction stir processed AA7075 alloy. Significant improvement in wear resistance of friction stir processed surface composites is attributed to the change in wear mechanism from abrasion to adhesion. It has also been observed that the surface metal matrix composites have shown better ballistic resistance compared to the substrate AA7075 alloy. Addition of solid lubricant MoS2 has reduced the depth of penetration of the projectile to half that of base metal AA7075 alloy. For the first time, the friction stir processing technique was successfully used to improve the wear and ballistic resistances of armour grade high strength AA7075 alloy.

  15. Improving corrosion and wear resistance of FV520B steel by high current pulsed electron beam surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Shengzhi, E-mail: ebeam@dlut.edu.cn [Key Laboratory of Material Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116024 (China); Zhao, Limin [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Zhang, Yanlong; Wang, Huihui [Key Laboratory of Material Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116024 (China)

    2015-08-01

    Highlights: • HCPEB surface treatment was conducted on FV520B steel. • Surface layer ∼10 μm was refined with elements homogenization. • Remelted layer exhibited 〈2 0 0〉 preferential orientation. • Corrosion potential increased and corrosion rate decreased one order of magnitude. • Wear resistance increased by 3 times. - Abstract: High current pulsed electron beam (HCPEB) surface treatment was conducted on FV520B steel with accelerating voltage 27 kV, pulse duration 2.5 μs, energy density 5 J/cm{sup 2} and 1–25 pulses. The surface microstructure and element distribution were examined by using scanning electron microscope (SEM), electron probe micro-analysis (EPMA) and X-ray diffraction (XRD) methods. After HCPEB treatments, the surface microstructure became refined and uniform with an average grain size less than 2 μm and a preferential solidification orientation in 〈2 0 0〉 direction. The thickness of surface remelted layer was ∼4 μm. The initial precipitated particles in surface layer of depth ∼10 μm were dissolved into the base matrix and gave a homogenous element distribution. The HCPEB modified surface exhibited an effective improvement in corrosion and wear resistance. The corrosion potential shifted towards positive and the corrosion rate decreased nearly one order of magnitude, while the wear resistance after 25 pulses of HCPEB treatment increased by 3 times as compared with the initial FV520B steel.

  16. Improvement in Abrasion Wear Resistance and Microstructural Changes with Deep Cryogenic Treatment of Austempered Ductile Cast Iron (ADI)

    Science.gov (United States)

    Šolić, Sanja; Godec, Matjaž; Schauperl, Zdravko; Donik, Črtomir

    2016-10-01

    The application of a deep cryogenic treatment during the heat-treatment processes for different types of steels has demonstrated a significant influence on their mechanical and tribological properties. A great deal of research was conducted on steels, as well as on other kinds of materials, such as hard metal, gray cast iron, aluminum, aluminum alloys, etc., but not on austempered ductile iron (ADI). In this research the influence of a deep cryogenic treatment on the microstructure and abrasive wear resistance of austempered ductile iron was investigated. The ductile cast iron was austempered at the upper ausferritic temperature, deep cryogenically treated, and afterwards tempered at two different temperatures. The abrasion wear resistance was tested using the standard ASTM G65 method. The microstructure was characterized using optical microscopy, field-emission scanning electron microscopy, electron back-scattered diffraction, and X-ray diffraction in order to define the microstructural changes that influenced the properties of the ADI. The obtained results show that the deep cryogenic treatment, in combination with different tempering temperatures, affects the matrix microstructure of the austempered ductile iron, which leads to an increase in both the abrasion wear resistance and the hardness.

  17. Sliding-wear resistance of pure near fully-dense B4C under lubrication with water, diesel fuel, and paraffin oil

    DEFF Research Database (Denmark)

    Ortiz, Angel L.; Leal, Victor Manuel Candelario; Borrero-López, Oscar

    2017-01-01

    The sliding-wear resistance of pure near fully-dense B4C is investigated, and the wear mode/mechanisms identified, under lubrication with water, diesel fuel, and paraffin oil. It is found that the wear is mild in the three cases, with specific wear rates (SWRs) of 10−16–10−17 m3/N m. Nonetheless......, the wear resistance of the B4C ceramic is one order of magnitude greater under oil lubrication (1016 N m/m3) than under water lubrication (1015 N m/m3), and twice as great for the specific case of paraffin oil than diesel fuel, attributable to the lubricant’s viscosity. It is also found that the wear mode...... is always abrasion, and that the wear mechanisms are plastic deformation and localized fracture with grain pullout. However, in agreement with the macro-wear data, the severity of the wear damage is lower under lubrication with paraffin oil, followed by diesel fuel, and lastly water. Finally...

  18. Way to increase back-up rolls cracking and wearing resistances at high-speed deposition with low heat input

    Directory of Open Access Journals (Sweden)

    Сергій Вікторович Щетинін

    2017-07-01

    Full Text Available The rolling-mill back-up rolls operate under high specific pressures conditions and are produced of high-carbon steel, prone to hot and cold cracking. Therefore crack resistance increase is an important scientific and technical problem. The impact of the electrode shape and heat input on the arc motion, and heat affected zone, the size of which determines the cold cracks formation and deposited metal flaking has been found. The arc moves along the electrode end face along the longitudinal axis or perpendicular to the weld pool in dependence on the ribbon position. The arc movement governs the heat input in the pool and if the surfacing regime is constant, the heating and cooling rates of the molten metal and heat affected zone as well. At surfacing with a perpendicular ribbon the heat affected zone decreases; at surfacing with a longitudinal ribbon and wire the heat affected zone increases. At surfacing with a composite electrode the heat affected zone reduces sharply while resistance to cracking and wearing increases. With the heat input reduction in weld pool side edges the heat affected zone reduces as well. At high speed surfacing with low heat input, the heat affected zone reduces, the tendency to cold cracking and deposited metal flaking decrease, welding stresses and specific pressure decrease, what results in resistance to cracking increase as well as the increase in wearing resistance. When energy decreases the deposited metal quality increases. Energy minimum results in maximum quality. The process of energy-saving high-speed deposition with low heat input, which provides microstructure reduction, heat input in the base metal and heat affected zone decrease, prevent cold cracking and deposited metal flaking increases both rolling mill back-up cracking resistance and wearing resistance has been developed

  19. Abrasive Wear Resistance of a Ti–Fe–Cr Alloy Obtained by Self-Propagating High-Temperature Synthesis and Modified with Boron and Carbon

    National Research Council Canada - National Science Library

    O. O. Onyshchuk

    2016-01-01

    ...–Cr system obtained by self-propagating hightemperature synthesis. It is shown that, as a result of the addition of carbon and boron, the heterogeneity of the structure and its wear resistance increase...

  20. RESEARCH OF PROCESSES ON FORMATION AND TRIBOTECHNICAL PROPERTIES OF WEAR-RESISTANT COMPOSITE GAS THERMAL COATINGS BEING DISPERSIVELY STRENGTHENED BY SYNTHETIC DIAMONDS AND ELECTRO-CORUNDUM

    Directory of Open Access Journals (Sweden)

    O. S. Kobjakov

    2011-01-01

    Full Text Available Formation processes, tribotechnical and wear-resistant properties of composite gas thermal coatings being dispersively strengthened by synthetic diamonds and electro-corundum are investigated in the paper.

  1. Influence of Melt State on the Properties of Nickel-based Powders for Wear-Resistant Coat

    Science.gov (United States)

    Baryshev, E.; Tyagunov, G.; Kostina, T.; Shmakova, K.

    2017-06-01

    The influence of time-temperature treatment on properties of the PG-SR-type alloys in cast condition, in produced powders and coatings is studied in this work. The temperature dependence of physical properties were obtained. These results and the comparative metallographic analysis have allowed offering the mode for time-temperature treatment of the liquid PG-SR-type alloys. Use of the time-temperature treatment when producing metal powders and coatings are as follows: the dispersibility of powders increases; the yield of powder fractions used for applying coatings increases; the powder porosity and oxidation decreases; oxidation resistance in various media increases; corrosion-, heat-, and wear resistance increases.

  2. Self-assembled thin film of imidazolium ionic liquid on a silicon surface: Low friction and remarkable wear-resistivity

    Energy Technology Data Exchange (ETDEWEB)

    Gusain, Rashi [CSIR-Indian Institute of Petroleum, Mohkampur, Dehardun 248005 (India); Academy of Scientific and Innovative Research, New Delhi 110025 (India); Kokufu, Sho [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan); Bakshi, Paramjeet S. [CSIR-Indian Institute of Petroleum, Mohkampur, Dehardun 248005 (India); Utsunomiya, Toru; Ichii, Takashi; Sugimura, Hiroyuki [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan); Khatri, Om P., E-mail: opkhatri@iip.res.in [CSIR-Indian Institute of Petroleum, Mohkampur, Dehardun 248005 (India); Academy of Scientific and Innovative Research, New Delhi 110025 (India)

    2016-02-28

    Graphical abstract: - Highlights: • Ionic liquid thin film is deposited on a silicon surface via covalent interaction. • Chemical and morphological features of ionic liquid thin film are probed by XPS and AFM. • Ionic liquid thin film exhibited low and steady friction along with remarkable wear-resistivity. - Abstract: Imidazolium-hexafluorophosphate (ImPF{sub 6}) ionic liquid thin film is prepared on a silicon surface using 3-chloropropyltrimethoxysilane as a bifunctional chemical linker. XPS result revealed the covalent grafting of ImPF{sub 6} thin film on a silicon surface. The atomic force microscopic images demonstrated that the ImPF{sub 6} thin film is composed of nanoscopic pads/clusters with height of 3–7 nm. Microtribological properties in terms of coefficient of friction and wear-resistivity are probed at the mean Hertzian contact pressure of 0.35–0.6 GPa under the rotational sliding contact. The ImPF{sub 6} thin film exhibited low and steady coefficient of friction (μ = 0.11) along with remarkable wear-resistivity to protect the underlying silicon substrate. The low shear strength of ImPF{sub 6} thin film, the covalent interaction between ImPF{sub 6} ionic liquid thin film and underlying silicon substrate, and its regular grafting collectively reduced the friction and improved the anti-wear property. The covalently grafted ionic liquid thin film further shows immense potential to expand the durability and lifetime of M/NEMS based devices with significant reduction of the friction.

  3. Corrosive-wear resistance of stainless steels for the impeller of slurry pump used in zinc hydrometallurgy process

    Directory of Open Access Journals (Sweden)

    Ping LI

    2005-08-01

    Full Text Available This paper presents corrosive-wear (C-W behaviors of three kinds of steels under the simulating condition of traditional zinc hydrometallurgy process by using a self-made rotating disk apparatus. Result shows that pure wear loss rate is significantly larger than pure corrosion loss rate. Under this C-W condition, the ranking of C-W resistance is S2 > S3 > S1 (S1: austenite stainless steel; S2: CD-4MCu duplex stainless steel; S3 :17-4PH stainless steel. S2 has excellent C-W resistance due to strong surface deformation strengthening effect of high-density dislocations of the γ phase. S3 also has excellent C-W resistance owing to high hardness and strength. However, S1 does not show good C-W resistance under strong erosion of liquid-solid slurry because of its single-phase austenitic structure and very low hardness. As a result, duplex stainless steels as well as 17-4 PH stainless steel can be used as impeller candidate materials in the zinc hydrometallurgy process due to their excellent C-W resistance and lower cost.

  4. Effect of tetrahedral amorphous carbon coating on the resistivity and wear of single-walled carbon nanotube network

    Energy Technology Data Exchange (ETDEWEB)

    Iyer, Ajai, E-mail: ajai.iyer@aalto.fi; Etula, Jarkko; Liu, Xuwen; Koskinen, Jari [Department of Materials Science and Engineering, School of Chemical Technology, Aalto University, P.O. Box 16200, 00076 Espoo (Finland); Kaskela, Antti; Kauppinen, Esko I. [NanoMaterials Group, Department of Applied Physics, School of Science, Aalto University, P.O. Box 15100, 00076 Espoo (Finland); Novikov, Serguei [Department of Micro and Nanosciences, Aalto University, P.O. Box 13500, 00076 Aalto (Finland)

    2016-05-14

    Single walled carbon nanotube networks (SWCNTNs) were coated by tetrahedral amorphous carbon (ta-C) to improve the mechanical wear properties of the composite film. The ta-C deposition was performed by using pulsed filtered cathodic vacuum arc method resulting in the generation of C+ ions in the energy range of 40–60 eV which coalesce to form a ta-C film. The primary disadvantage of this process is a significant increase in the electrical resistance of the SWCNTN post coating. The increase in the SWCNTN resistance is attributed primarily to the intrinsic stress of the ta-C coating which affects the inter-bundle junction resistance between the SWCNTN bundles. E-beam evaporated carbon was deposited on the SWCNTNs prior to the ta-C deposition in order to protect the SWCNTN from the intrinsic stress of the ta-C film. The causes of changes in electrical resistance and the effect of evaporated carbon thickness on the changes in electrical resistance and mechanical wear properties have been studied.

  5. Wear-resistant rose petal-effect surfaces with superhydrophobicity and high droplet adhesion using hydrophobic and hydrophilic nanoparticles.

    Science.gov (United States)

    Ebert, Daniel; Bhushan, Bharat

    2012-10-15

    Surfaces exhibiting the so-called "petal effect" (superhydrophobicity with high droplet adhesion) have potential for applications such as the transport of small volumes of liquid. It is known that the microstructure pitch value and nanostructure density are important in achieving this effect, both in rose petals themselves and in synthetic petal-effect surfaces. However, the effect of the surface energy of materials on these values has not been systematically studied. In addition, wear resistance, which is critical for industrial applications, has rarely been examined for petal-effect surfaces. In this study, surfaces of varying microstructure pitch and nanostructure density were fabricated by depositing ZnO nanoparticles onto micropatterned substrates. The prepared surfaces were then modified with octadecylphosphonic acid (ODP) in order to hydrophobize the ZnO nanoparticles. The wettability of the surfaces was characterized both before and after ODP modification. The effect of hydrophobizing the nanostructure was examined with regards to the values of microstructure pitch and nanostructure density necessary to achieve the petal effect. In addition, to study wear resistance for industrial applications, a wear experiment was performed using an atomic force microscope (AFM). Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Imposed Thermal Fatigue and Post-Thermal-Cycle Wear Resistance of Biomimetic Gray Cast Iron by Laser Treatment

    Science.gov (United States)

    Sui, Qi; Zhou, Hong; Zhang, Deping; Chen, Zhikai; Zhang, Peng

    2017-08-01

    The present study aims to create coupling biomimetic units on gray cast iron substrate by laser surface treatment (LST). LSTs for single-step (LST1) and two-step (LST2) processes, were carried out on gray cast iron in different media (air and water). Their effects on microstructure, thermal fatigue, and post-thermal-cycle wear (PTW) resistance on the specimens were studied. The tests were carried out to examine the influence of crack-resistance behavior as well as the biomimetic surface on its post-thermal-cycle wear behavior and different units, with different laser treatments for comparison. Results showed that LST2 enhanced the PTW behaviors of gray cast iron, which then led to an increase in its crack resistance. Among the treated cast irons, the one treated by LST2 in air showed the lowest residual stress, due to the positive effect of the lower steepness of the thermal gradient. Moreover, the same specimen showed the best PTW performance, due to its superior crack resistance and higher hardness as a result of it.

  7. Wear surface damage of a Stainless Steel EN 3358 aeronautical component subjected to sliding

    Directory of Open Access Journals (Sweden)

    Ferdinando Felli

    2013-01-01

    Full Text Available The present paper describes the failure analysis of an aircraft component subjected to several episodes of in service failure, resulted in loss of the aircraft safety. Modern aircrafts are provided with mechanical systems which have the task to open not pressurized hatches during landing. The components of such systems are subject to considerable mechanical stresses in harsh environment (presence of moisture and pollutants, significant and sudden temperature variations. The system is constituted by a sliding piston, a related nipple and by a locking system consisting of 4 steel spheres which are forced into a countersink machined on the piston when the hatches is open. The whole system is activated by a preloaded spring. The machined parts, nipple and piston, are made of EN3358 steel (X3CrNiMo13-8-2, a precipitation hardening stainless steel with very low content of carbon often used in the aerospace. The samples provided by the manufacturer present different types of damage all referable to phenomena relative to the sliding of the piston inside the nipple. The present paper describes the different damage observed and the microstructure of the material, then are reported the results obtained from the characterization of the material of the samples by means of optical and electronic microscopy, carried out to define the mechanisms involved in the system seizure. In order to define the primary cause of failure and to propose solutions to be adopted, also analyzing the criticality of using this PH stainless steel for this application, the results of different tests were compared with system design and working data.

  8. Effect of the Cutting Tool Geometry on the Tool Wear Resistance When Machining Inconel 625

    Directory of Open Access Journals (Sweden)

    Tomáš Zlámal

    2017-12-01

    Full Text Available The paper deals with the design of a suitable cutting geometry of a tool for the machining of the Inconel 625 nickel alloy. This alloy is among the hard-to-machine refractory alloys that cause very rapid wear on cutting tools. Therefore, SNMG and RCMT indexable cutting insert were used to machine the alloy. The selected insert geometry should prevent notch wear and extend tool life. The alloy was machined under predetermined cutting conditions. The angle of the main edge and thus the size and nature of the wear changed with the depth of the material layer being cut. The criterion for determining a more suitable cutting geometry was the tool’s durability and the roughness of the machined surface.

  9. Influence of Hardness, Matrix and Carbides in Combination with Nitridation on Abrasive Wear Resistance of X210Cr12 Tool Steel

    Directory of Open Access Journals (Sweden)

    Martin Orečný

    2016-10-01

    Full Text Available Materials used in abrasive wear conditions are usually selected according to their microstructure and hardness, however, other factors such as grain size, matrix saturation, carbides size and morphology are rarely considered. Therefore, the present study deals with the influence of different heat and chemical-heat treatments including their combination on abrasive wear resistance of X210Cr12 tool steel. The effects of material hardness, carbide morphology and microstructure on wear resistance after quenching and nitriding were also investigated. One sample series was quenched after austenitization at 960 °C for 20 min and tempered at 180 °C for 2 h. The second sample series was quenched from 1060 °C austenitization for 20 min and afterwards twice tempered at 530 °C for 1 h. From both the quenched and tempered states, one half of the samples was gas nitrided in NH3 atmosphere for 3 h and then diffusion annealed in N2 atmosphere for 4 h. Abrasion wear tests were performed by sliding the samples on Al2O3 paper. The samples weight loss was considered the main criterion for the wear resistance evaluation. The microstructures, nitrided layers and worn surfaces were observed using SEM microscopy. The highest abrasion wear resistance was obtained for the nitrided samples that were previously quenched from 1060 °C and tempered at 530 °C.

  10. Wear resistance and friction reduction in acrylo nitrile butadiene rubber through hybrid combination of graphite flakes and nano tungsten disulphide

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Neha, E-mail: neha87bhu@gmail.com [Defence Material Store Research Development and Establishment (DMSRDE), DRDO, GT Road, Kanpur 208013, U.P (India); Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra (India); Pandey, Akanksha; Parihar, A. S.; Mishra, A. K.; Mukhopadhyay, K.; Prasad, N. E. [Defence Material Store Research Development and Establishment (DMSRDE), DRDO, GT Road, Kanpur 208013, U.P (India); Gandhi, M. N.; Bhattacharyya, A. R. [Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra (India)

    2016-05-06

    Friction and wear have considerable role in the life span of two interacting parts. Incorporation of nanofillers in polymers/elastomers matrix causes commendable changes in its tribologicalproperties. The main purpose of this work is to reduce the coefficient of friction and wear rate of Acrylo Nitrile Butadiene rubber (NBR). To achieve such objective traditionally well knownlubricants graphite(G), tungsten disulphide (WS{sub 2}) and there hybrid combination was incorporated in NBR matrix. Effect of applied load (force) and concentration of fillers on tribological properties of NBR had been studied. The filler incorporation enhanced the hardnessby 8%, showed resistance to hydraulic oil and aging effect also got improved significantly. A particular optimized concentration of NBR with hybrid combination of 2% WS{sub 2} and 4% Graphite showed minimum coefficient of friction as well as wear rate. A hypothesis could be attributed that similar lamellar structure of WS{sub 2} and Graphite along with formation of a stable nanoscale disulfide tribofilmcould result in lowering of friction. These substantially improved properties of nanoreinforced rubber materials would definitely pave promising path for plethora of potential technological applications.

  11. Laser surface modification of Ti6Al4V-Cu for improved microhardness and wear resistance properties

    CSIR Research Space (South Africa)

    Erinosho, MF

    2017-06-01

    Full Text Available sample was etched for 10 -15 seconds, cleaned with ethanol, rinsed under running water and dried off prior to Scanning Electron Microscope (SEM) and optical microscopic (OM) observations. The SEM was conducted on the samples using the TESCAN...Laser Surface Modification of Ti6Al4V-Cu for Improved Microhardness and Wear Resistance Properties The microstructures of the selected Ti6Al4V-3Cu and Ti6Al4V-5Cu alloys observed by SEM and Optical microscope (OM) are presented Figure 5. The SEM...

  12. Clinical safety and wear resistance of the phospholipid polymer-grafted highly cross-linked polyethylene liner.

    Science.gov (United States)

    Moro, Toru; Takatori, Yoshio; Tanaka, Sakae; Ishihara, Kazuhiko; Oda, Hiromi; Kim, Yoon Taek; Umeyama, Takashige; Fukatani, Eisei; Ito, Hideya; Kyomoto, Masayuki; Oshima, Hirofumi; Tanaka, Takeyuki; Kawaguchi, Hiroshi; Nakamura, Kozo

    2017-09-01

    To reduce the production of wear particles and subsequent aseptic loosening, we created a human articular cartilage-mimicked surface for a highly cross-linked polyethylene liner, whose surface grafted layer consisted of a biocompatible phospholipid polymer, poly(2-methacryloyloxyethyl phosphorylcholine). Although our previous in vitro findings showed that poly(2-methacryloyloxyethyl phosphorylcholine)-grafted particles were biologically inert and caused no subsequent bone resorptive responses, and poly(2-methacryloyloxyethyl phosphorylcholine) grafting markedly decreased wear in hip joint simulator tests, the clinical safety, and in vivo wear resistance of poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liners remained open to question. Therefore, in the present study, we evaluated clinical and radiographic outcomes of poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liners 5 years subsequent to total hip replacement in 68 consecutive patients. No reoperation was required for any reason, and no adverse events were associated with the implanted liners. The average Harris Hip Score increased from 38.6 preoperatively to 96.5 5 years postoperatively, and health-related quality of life, as indicated by the Short Form 36 Health Survey, improved. Radiographic analyses showed no periprosthetic osteolysis or implant migration. Between 1 and 5 years postoperatively, the mean steady-state wear rate was 0.002 mm/year, which represented a marked reduction relative to other highly cross-linked polyethylene liners, and appeared to be unaffected by patient-related or surgical factors. Although longer follow up is required, poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liners improved mid-term clinical outcomes. The clinical safety and wear-resistance results are encouraging with respect to the improvement of long-term clinical outcomes with poly(2

  13. Determination of radiation resistant of electronic components in robot system

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hee Dong [Kyungpook National University, Taegu (Korea); Kim, Do Sung [Taegu University, Taegu (Korea); Woo, Hong [Kyungsan University, Kyungsan (Korea)

    1998-04-01

    We investigated the characteristic change for the electronic components of the systems which were used in radiation area, when those were exposured by gamma rays. Bipolar transistor, FET, TTL, CMOS, operational amplifier, some capacitors, and several electronic components were selected for experiment. We applied irradiated gamma ray to the electronic components in the range of 10{sup 6} rad, by {sup 6}0Co(KAERI). We made up appropriate assessment circuit for each electronic component during the performance test, and assessed the reliability and radiation-resistance of them for the each radiation irradiation. (author). 59 refs., 35 figs., 8 tabs.

  14. Development of Advanced Wear and Corrosion Resistant Systems Through Laser Surface Alloying and Materials Simulations

    Energy Technology Data Exchange (ETDEWEB)

    R. P. Martukanitz and S. Babu

    2007-05-03

    Laser surfacing in the form of cladding, alloying, and modifications are gaining widespread use because of its ability to provide high deposition rates, low thermal distortion, and refined microstructure due to high solidification rates. Because of these advantages, laser surface alloying is considered a prime candidate for producing ultra-hard coatings through the establishment or in situ formation of composite structures. Therefore, a program was conducted by the Applied Research Laboratory, Pennsylvania State University and Oak Ridge National Laboratory to develop the scientific and engineering basis for performing laser-based surface modifications involving the addition of hard particles, such as carbides, borides, and nitrides, within a metallic matrix for improved wear, fatigue, creep, and corrosion resistance. This has involved the development of advanced laser processing and simulation techniques, along with the refinement and application of these techniques for predicting and selecting materials and processing parameters for the creation of new surfaces having improved properties over current coating technologies. This program has also resulted in the formulation of process and material simulation tools capable of examining the potential for the formation and retention of composite coatings and deposits produced using laser processing techniques, as well as positive laboratory demonstrations in producing these coatings. In conjunction with the process simulation techniques, the application of computational thermodynamic and kinetic models to design laser surface alloying materials was demonstrated and resulted in a vast improvement in the formulation of materials used for producing composite coatings. The methodology was used to identify materials and to selectively modify microstructures for increasing hardness of deposits produced by the laser surface alloying process. Computational thermodynamic calculations indicated that it was possible to induce the

  15. Abrasive wear resistance optimization of three different carbide coatings by the Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Guer, Ali Kaya [Firat Univ., Elazig (Turkey). Dept. of Metallurgy and Materials; Kaya, Sinan [Firat Univ., Elazig (Turkey). Faculty of Technology

    2017-06-01

    In this study, FeCrC, SiC and B{sub 4}C powders were alloyed on the surface of AISI 430 ferritic stainless steel by plasma arc welding. The mass losses of the abrasive wear of the AISI 430 substrate were examined under the loads of 6, 10 and 16 N and in the distances of 10, 20 and 30 m by using Taguchi design method. The results of abrasive wear test were optimized by the minimum optimal control characteristics of the Taguchi procedure and the results were analyzed by using graphical methods. The Taguchi procedure is an important approach to achieve high quality without increasing the cost during the optimization of process parameters. The orthogonal planes of maximum effects of the controllable process parameters and minimum effects of uncontrollable process parameters were employed in the Taguchi method.

  16. Impact of UHMWPE texture on friction and wear resistance of hip prosthesis

    Directory of Open Access Journals (Sweden)

    Eddoumy Fatima

    2013-11-01

    Full Text Available Ultra High Molecular Weight PolyEthylene (UHMWPE is a polymer widely used in hip implants (prostheses as a bearing surface against metal, because of its good mechanical properties and biocompatibility [1]. Nevertheless, the durability of such implants is limited because of failure resulting from osteolysis and aseptic loosening. These two phenomenons are due to the immune response of human body consecutive to the apparition of wear particles of UHMWPE with time.

  17. Analysis Of The Austenite Grain Growth In Low-Alloy Boron Steel With High Resistance To Abrasive Wear

    Directory of Open Access Journals (Sweden)

    Białobrzeska B.

    2015-09-01

    Full Text Available Today low-alloy steels with boron achieve high resistance to abrasive wear and high strength. These features are obtained by using advanced technology of manufacturing. This makes boron steels increasingly popular and their application more diverse. Application of these steels can extend the lifetime of very expensive machine construction in many industries such as mining, the automotive, and agriculture industries. An interesting subgroup of these materials is steel with boron intended for heat treatment. These steels are supplied by the manufacturer after cold or hot rolling so that it is possible for them to be heat treated in a suitable manner by the purchaser for its specific application. Very important factor that determines the mechanical properties of final product is austenite grain growth occurring during hot working process such us quenching or hot rolling. Investigation of the effect of heating temperature and holding time on the austenite grain size is necessary to understand the growth behavior under different conditions. This article presents the result of investigation of austenite grain growth in selected low-allow boron steel with high resistance to abrasive wear and attempts to describe the influence of chemical composition on this process.

  18. Wear and Corrosion Resistance of Fe Based Coatings by HVOF Sprayed on Gray Cast-Iron for Automotive Application

    Directory of Open Access Journals (Sweden)

    M.S. Priyan

    2014-12-01

    Full Text Available In this study, commercially available FeSiNiCr and FeBCr alloy powders were designed with suitable compositions, gas atomized and then coated on gray cast-iron substrate. The microstructures of the feed stock Fe based alloy powders and the coatings were investigated by means of optical microscopy (OM, X-Ray diffraction (XRD, Thermogravimetric analysis (TGA and Scanning Electron Microscopy (SEM. In the present study, both the coating materials experienced two-body wear mechanisms. The results showed that for loads of 0.05 N, 0.1 N and 0.2 N, the wear resistance of FeBCr coating was less than FeSiNiCr by 44 %, 40 % and 31 %, respectively. The results indicated that the coated substrates exhibited lower corrosion current densities and lower corrosion rates, when placed in 20 wt.% H2SO4 solutions. In addition, the use of optimal spraying parameters/conditions gave improvements to the corrosion resistance of the substrates that had been treated with the crystalline coating.

  19. Influence of high sintering pressure on the microhardness and wear resistance of diamond powder and silicon carbide-based composites

    Directory of Open Access Journals (Sweden)

    Osipov Oleksandr Sergueevitch

    2004-01-01

    Full Text Available The work reported on here involved the development of several samples of "diamond-SiC" composite produced under sintering pressures of up to 9.0 GPa at temperatures of up to 1973 7K. The average size of the diamond micropowder crystals used was 40/28 µm. The sintering process was carried out in a 2500-ton hydraulic press equipped with an anvil-type high-pressure device having a toroidal work surface and a central concavity diameter of 20 mm. The microhardness and wear resistance of the samples were found to be dependent on the sintering pressure. The experimental results indicated that the maximum microhardness and minimum wear resistance coefficients of each compact were attained when the pressure applied during sintering exceeded 6.5 GPa. Based on the established values of pressure, this study served to identify the types of devices applicable for the manufacture of composite material inserts for a variety of rock drilling applications.

  20. Silver nanosheet-coated copper nanowire/epoxy resin nanocomposites with enhanced electrical conductivity and wear resistance

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Ningning; Ma, Jingyi; Zhang, Yujuan; Yang, Guangbin; Zhang, Shengmao, E-mail: zsm@henu.edu.cn; Zhang, Pingyu [Henan University, Engineering Research Center for Nanomaterials (China)

    2017-03-15

    Silver (Ag) nanosheet-coated Cu nanowires (denoted as Cu@AgNWs) were prepared with a facile transmetalation reaction method. The effect of reaction conditions on the morphology and microstructure of the as-prepared Cu@AgNWs was investigated, and the thermal stability of Cu@AgNWs was evaluated by thermogravimetric analysis. In the meantime, the as-prepared Cu@AgNWs were used as the nanofillers of epoxy resin (EP), and their effect on the electrical conductivity and wear resistance of the EP-matrix composites was examined. Results indicate that the as-prepared Cu@AgNWs consist of CuNW core and Ag nanosheet shell. The Ag nanosheet shell can well inhibit the oxidation of the CuNW core, thereby providing the as-prepared Cu@AgNWs with good thermal stability even at an elevated temperature of 230 °C. The reaction temperature, Cu/Ag molar ratio, Cu dispersion concentration, and the dropping speed of silver ammonia reagent are suggested to be 40 °C, 5:1, 1% (mass fraction), and poured directly, respectively. Resultant Cu@AgNWs exhibit desired morphology and performance and can effectively increase the electrical conductivity and wear resistance of EP. This could make it feasible for the Cu@AgNW-EP composite to be applied as an electrostatic conductive material.

  1. Elastic Bands as a Component of Periodized Resistance Training.

    Science.gov (United States)

    Joy, Jordan M; Lowery, Ryan P; Oliveira de Souza, Eduardo; Wilson, Jacob M

    2016-08-01

    Joy, JM, Lowery, RP, Oliveira de Souza, E, and Wilson, JM. Elastic bands as a component of periodized resistance training. J Strength Cond Res 30(8): 2100-2106, 2016-Variable resistance training (VRT) has recently become a component of strength and conditioning programs. Prior research has demonstrated increases in power and/or strength using low loads of variable resistance. However, no study has examined using high loads of variable resistance as a part of a periodized training protocol to examine VRT within the context of a periodized training program and to examine a greater load of variable resistance than has been examined in prior research. Fourteen National Collegiate Athletic Association division II male basketball players were recruited for this study. Athletes were divided equally into either a variable resistance or control group. The variable resistance group added 30% of their 1 repetition maximum (1RM) as band tension to their prescribed weight 1 session per week. Rate of power development (RPD), peak power, strength, body composition, and vertical jump height were measured pretreatment and posttreatment. No baseline differences were observed between groups for any measurement of strength, power, or body composition. A significant group by time interaction was observed for RPD, in which RPD was greater in VRT posttraining than in the control group. Significant time effects were observed for all other variables including squat 1RM, bench press 1RM, deadlift 1RM, clean 3RM, vertical jump, and lean mass. Although there were no significant group ×-time interactions, the VRT group's percent changes and effect sizes indicate a larger treatment effect in the squat and bench press 1RM values and the vertical jump performed on the force plate and vertec. These results suggest that when using variable resistance as a component of a periodized training program, power and strength can be enhanced. Therefore, athletes who add variable resistance to 1 training

  2. Wear resistance evaluation of palm fatty acid distillate using four-ball tribotester

    Science.gov (United States)

    Golshokouh, Iman; Ani, Farid Nasir; Syahrullail, S.

    2012-06-01

    Petroleum reserves are declining nowadays while ironically petroleum is a major source of pollution despite many uses. Researchers are in effort to find an alternative to replace petroleum as a lubricant. One of the best replace sources for petroleum is bio-oil. In this paper, a comparative study of friction and wear was carried out using a fourball tester. In this research, Palm Fatty Acid Distillate (PFAD) and Jatropha oil, two well-known oils from the vegetable family oils were compared with Hydraulic mineral oil and commercial mineral Engine oil. All investigated oils in this study are used in industries as lubricants. PFAD is a product from refined crude palm oil. It exists as a light brown solid at room temperature and Jatropa oil is produced from the seeds of the Jatropha cruces, a plant that grows in marginal lands. For the wear test, the experimental research condition was comparing four kind of oils with ASTM condition in which the load applied was 392N. The sliding speed was 1200rpm under the lubricant temperature of 75 degree Celsius. The experiment was run for 3600 seconds. The experimental results demonstrated that the PFAD and Jatropha oils exhibited better performance in term of friction and wear compared to Hydraulic and Engine mineral oils.

  3. High Kinetic Energy Penetrator Shielding and High Wear Resistance Materials Fabricated with Boron Nitride Nanotubes (BNNTS) and BNNT Polymer Composites

    Science.gov (United States)

    Kang, Jin Ho (Inventor); Park, Cheol (Inventor); Sauti, Godfrey (Inventor); Smith, Michael W. (Inventor); Jordan, Kevin C. (Inventor); Lowther, Sharon E. (Inventor); Bryant, Robert George (Inventor)

    2015-01-01

    Boron nitride nanotubes (BNNTs), boron nitride nanoparticles (BNNPs), carbon nanotubes (CNTs), graphites, or combinations, are incorporated into matrices of polymer, ceramic or metals. Fibers, yarns, and woven or nonwoven mats of BNNTs are used as toughening layers in penetration resistant materials to maximize energy absorption and/or high hardness layers to rebound or deform penetrators. They can be also used as reinforcing inclusions combining with other polymer matrices to create composite layers like typical reinforcing fibers such as Kevlar.RTM., Spectra.RTM., ceramics and metals. Enhanced wear resistance and usage time are achieved by adding boron nitride nanomaterials, increasing hardness and toughness. Such materials can be used in high temperature environments since the oxidation temperature of BNNTs exceeds 800.degree. C. in air. Boron nitride based composites are useful as strong structural materials for anti-micrometeorite layers for spacecraft and space suits, ultra strong tethers, protective gear, vehicles, helmets, shields and safety suits/helmets for industry.

  4. Influence of halogen irradiance on short- and long-term wear resistance of resin-based composite materials.

    LENUS (Irish Health Repository)

    Bhamra, Gurcharn S

    2009-02-01

    The Oregon Health Science University (OHSU) four-chamber oral wear simulator was used to examine the impact of halogen irradiance on the short- and long-term wear behavior of four-methacrylate resin-based composites (RBCs). The hypothesis proposed was that exacerbated wear would occur following the long-term wear of RBCs irradiated under non-optimized irradiance conditions.

  5. Measurement of the Resistance of Treated Metal Foils to Scrubbing Abrasion Using a Modified Reciprocating Wear Test

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jun [ORNL; Blau, Peter Julian [ORNL; Sikka, Vinod K [ORNL

    2007-01-01

    A reciprocating wear test method has been developed to evaluate the resistance of metal foils to scrubbing abrasion. Development included the definition of a quantitative measure of the scrubbing resistance. In order to test the ability of the new method to differentiate between surface treatments, four versions of Type 316 stainless steel foils were tested: annealed (A-NT), cold-worked (C-NT), annealed plus a case-hardened (A-T), and cold-worked plus case-hardened (C-T). Measurements were made of their scrubbing resistance using commercial kitchen scrub pads as the counterface material. Results showed that the case-hardening process significantly increased the scrubbing resistance both under dry conditions and with cleaning solutions to lubricate the contact. While this linearly-reciprocating method does not simulate the circular, overlapping motion commonly occurring in service, results indicated that the new test method could sufficiently discriminate levels of two-body abrasion behavior, and therefore can be useful for studying the effects of surface treatments on abrasion resistance.

  6. Hydrophobicity attainment and wear resistance enhancement on glass substrates by atmospheric plasma-polymerization of mixtures of an aminosilane and a fluorocarbon

    Energy Technology Data Exchange (ETDEWEB)

    Múgica-Vidal, Rodolfo, E-mail: rodolfo.mugica@alum.unirioja.es [Department of Mechanical Engineering, University of La Rioja, c/ Luis de Ulloa 20, 26004, Logroño, La Rioja (Spain); Alba-Elías, Fernando, E-mail: fernando.alba@unirioja.es [Department of Mechanical Engineering, University of La Rioja, c/ Luis de Ulloa 20, 26004, Logroño, La Rioja (Spain); Sainz-García, Elisa, E-mail: elisa.sainzg@unirioja.es [Department of Mechanical Engineering, University of La Rioja, c/ Luis de Ulloa 20, 26004, Logroño, La Rioja (Spain); Pantoja-Ruiz, Mariola, E-mail: mpruiz@ing.uc3m.es [Materials Science and Engineering Department, IAAB, Materials Performance Group, University Carlos III of Madrid, Av. Universidad 30, 28911, Leganés, Madrid (Spain)

    2015-08-30

    Graphical abstract: - Highlights: • APTES and PFH were used to coat glass by non-thermal atmospheric jet plasma. • A mixture of 75% of APTES and 25% PFH produced the best sample of this work. • Hydrophobicity was achieved by changes in surface morphology and chemistry. • Wear resistance was enhanced by the formation of siloxane groups. - Abstract: Mixtures of different proportions of two liquid precursors were subjected to plasma-polymerization by a non-thermal atmospheric jet plasma system in a search for a coating that achieves a hydrophobic character on a glass substrate and enhances its wear resistance. 1-Perfluorohexene (PFH) was chosen as a low-surface-energy precursor to promote a hydrophobic character. Aminopropyltriethoxysilane (APTES) was chosen for its contribution to the improvement of wear resistance by the formation of siloxane bonds. The objective of this work was to determine which of the precursors’ mixtures that were tested provides the coating with the most balanced enhancement of both hydrophobicity and wear resistance, given that coatings deposited with fluorocarbon-based precursors such as PFH are usually low in resistance to wear and coatings deposited with APTES are generally hydrophilic. The coatings obtained were analyzed by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infra-Red (FTIR) spectroscopy, X-ray Photoelectron Spectroscopy (XPS), static Water Contact Angle (WCA) measurements, tribological ball-on-disc tests and contact profilometry. A relationship between the achievement of a hydrophobic character and the modifications to roughness and surface morphology and the incorporation of fluorocarbon groups in the surface chemistry was observed. Also, it was seen that the wear resistance was influenced by the SiOSi content of the coatings. In turn, the SiOSi content appears to be directly related to the percentage of APTES used in the mixture of precursors. The best conjunction of

  7. Wear and Corrosion Resistance of Thick Ti-6Al-4V Coating Deposited on Ti-6Al-4V Substrate via High-Pressure Cold Spray

    Science.gov (United States)

    Khun, N. W.; Tan, A. W. Y.; Sun, W.; Liu, E.

    2017-08-01

    Ti-6Al-4V (Ti64) coating with a thickness of about 9 mm was deposited on commercial Ti64 substrate via a high-pressure cold spray process. The microstructure, hardness, and wear and corrosion resistance of the Ti64 coating were systematically investigated. The hardness of the Ti64 coating was higher than that of the Ti64 substrate due to the cold-worked microstructure of the coating. The tribological results showed that there was no significant difference in the surface wear rates of the Ti64 coating measured on its different layers while the surface wear resistance of the Ti64 coating was lower than its cross-sectional wear resistance. The corrosion results showed that the Ti64 coating did not effectively prevent its underlying Ti64 substrate from corrosion due to the occurrence of pores in the coating microstructure. It could be concluded that the hardness and wear resistance of the Ti64 coating were comparable to those of the commercial Ti64 substrate.

  8. Microhardness and wear resistance of PEO-coated 5754 aluminum alloy

    Science.gov (United States)

    Vyaliy, I. E.; Egorkin, V. S.; Sinebryukhov, S. L.; Minaev, A. N.; Gnedenkov, S. V.

    2017-09-01

    We present results of the study aimed at assessing the effect of duty cycle (D) during plasma electrolytic oxidation (PEO) on protective properties of the coatings produced on 5754 aluminum alloy. It is shown that increasing the duty cycle of a microsecond current pulses leads to increased hardness and reduced abrasive wear of the PEO-layers, improving mechanical properties. The obtained data allowed confirming, that increasing the amount of energy consumed for coating growth leads to the formation of thicker PEO-layers with improved tribological properties. The effect of duty cycle during plasma electrolytic oxidation on protective properties of the produced coatings was assessed.

  9. Sputter deposition and characterisation of hard wear-resistant Ti/TiN multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Simmonds, M.C.; Swygenhoven, H. van [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Multilayered Ti/TiN thin films have been synthesized by magnetron sputter deposition. Alternating layers of Ti and TiN with layer thickness in the 5-50 nm range are sequentially deposited. The structure of the films have been characterised by atomic force microscopy (AFM), X-ray diffraction and reflection and Auger depth profiling. The mechanical properties have been investigated using pin-on-disc wear rate testing, nanoindentation determination of hardness and micro scratch testing. (author) 1 fig., 3 refs.

  10. Polishability and wear resistance of splint material for oral appliances produced with conventional, subtractive, and additive manufacturing.

    Science.gov (United States)

    Huettig, Fabian; Kustermann, Achim; Kuscu, Ebru; Geis-Gerstorfer, Jürgen; Spintzyk, Sebastian

    2017-11-01

    Occlusal splints to treat bruxism are commonly made from polymethylmethacrylate (PMMA) in a manual workflow (powder-liquid technique). Today digitalization allows a machine-based manufacturing in subtractive (milling) and additive (printing) means using industrial-made PMMA or comparable resins. An in-vitro study should assess the surface finish and screen the wear resistance of conventional and industrial materials. Therefore, a total of 30 specimens made from conventionally PMMA (group C; powder-liquid, Palapress), polycarbonate ingots (group S; innoBlanc splint plus), and light-curing resin (group A; VarseoWax splint) were polished to examine the surface roughness (Ra) by profilometry and further analyzed by SEM. The specimens were loaded with a steatite ball moving 5000 times along 1cm with 5N of surface pressure under constant wetting (artificial saliva). The total height of profile (Pt) was calculated by further profilometry of the specimens. All specimen showed initially comparable Ra values ranging between 0.06 and 0.05µm (SD = 0.01) after polishing. SEM investigations revealed no visual cues for scratches or irregularities in any group. After abrasion test, the comparison of the wear depths, revealed mean Pt values of 111.4µm (SD = 18.5) in C, 85.7µm (SD = 21.5) in S, and 99.1µm (SD = 21.5) in A, whereas the mean of S was statistically different from C (p = 0.025). No signs of abrasion were found on the steatite balls. All materials showed comparable polished surfaces and a similar scale of wear. It remains questionable if the detected statistical differences are of clinical relevance, but indicates the need for tests of novel materials, especially in additive manufacturing. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Anodized porous titanium coated with Ni-CeO2 deposits for enhancing surface toughness and wear resistance

    Science.gov (United States)

    Zhou, Xiaowei; Ouyang, Chun

    2017-05-01

    In order to make large improvements of surface toughness and wear resistance for pure titanium (Ti) substrate, anodic titanium oxide (ATO) surface with nanoporous structure was coated with the Ni-CeO2 nanocomposite coatings. Regarding TiO2 barrier layer on Ti surface to inhibit its electrochemical activity, pre-treatments were successively processed with anodizing, sensitizing, activating, and then followed by electroless Ni-P film to be acted as an activated layer for electroplating Ni-CeO2 deposits. The existing Pd atoms around ATO nanopores were expected as the heterogeneous nucleation sites for supporting the growing locations of electroless Ni-P film. The innovative of interface design using porous structure was introduced for bonding pinholes to achieve a metallurgical adhesion interface between Ti substrate and surface coatings. Besides the objectives of this work were to elucidate how effects by the adding CeO2 nanoparticles on modifying microstructures and wear mechanisms of Ni-CeO2 nanocomposite coatings. Many efforts of XRD, FE-SEM, TEM and Nanoindentation tests were devoted to comparing different wear behaviors of Ni-CeO2 coatings relative to pure nickel. Results indicated that uniform-distributed Ti nanopores with an average diameter size of ∼200 nm was achieved using the Phosphate-type anodizing solution at DC 150 V. A worn surface without fatigue cracks was observed for TAO surface coated with Ni-CeO2 deposits, showing the existing Ce-rich worn products to be acted as a solid lubricant phase for making a self-healing effect on de-lamination failures. More important, this finding will be the guidelines for Ce-rich precipitations to be expected as the strengthening phase in anodized porous of Ti, Al and Mg alloys for intensifying their surface properties.

  12. Influence of the angle of irradiation of the Er,Cr:YSGG laser on the morphology, attachment of blood components, roughness, and root wear: in vitro study.

    Science.gov (United States)

    de Oliveira, Guilherme José Pimentel Lopes; Pavone, Chaine; Sampaio, José Eduardo Cézar; Marcantonio, Rosemary Adriana Chiérici

    2010-11-01

    To evaluate the influence of the working tip angulation of the Er,Cr:YSGG laser on the morphology, attachment of blood components, roughness, and wear on irradiated root surfaces compared to scaling and root planing (SRP). The present study used 45 teeth, of which 25 were used for the analysis of the morphology and the attachment of blood components and 20 were used for the analysis of the roughness and of the root wear. The teeth were randomly divided into five groups according to the treatment applied: (G1) Laser Er,Cr:YSGG-30°; (G2) Laser Er,Cr:YSGG-45°; (G3) Laser Er,Cr:YSGG-60°; (G4) Laser Er,Cr:YSGG-90°; and (G5) SRP. The root surfaces irradiated with the Er,Cr:YSGG laser working angulation tip of 45° and 60°, and the samples scaled with manual instruments presented greater attachment of blood components than the group where the Er,Cr:YSGG laser irradiated at working tip angulation of 30° and 90° (Pirradiated with the Er,Cr:YSGG laser were rougher than the samples scaled with manual instruments (Pirradiated with the Er,Cr:YSGG laser at an angle of 30° presented the least wear in comparison to all the other treatments (Pirradiated root surfaces proved to be rougher than those scaled with manual instruments; however, irradiation at working tip angulations of 45° and 60° produced results of attachment of blood components and root wear comparable with those obtained with manual instrumentation. © 2010 Wiley-Liss, Inc.

  13. A New Design of In Situ Ti(C,N) Reinforced Composite Coatings and Their Microstructures, Interfaces, and Wear Resistances.

    Science.gov (United States)

    Wang, Mingliang; Cui, Hongzhi; Wei, Na; Ding, Lei; Zhang, Xinjie; Zhao, Yong; Wang, Canming; Song, Qiang

    2018-01-31

    Here, a unique combination of a novel carbon-nitrogen source (g-C 3 N 4 ) with different mole ratios of Ti/g-C 3 N 4 has been utilized to fabricate iron matrix composite coatings by a synchronized powder feeding plasma transferred arc (PTA) cladding technology. The results show that submicron Ti(C,N) particles are successfully fabricated in situ on a Q235 low carbon steel substrate to reinforce the iron matrix composite coatings and exhibit dense microstructures and good metallurgical bonding between the coating and the substrate. The microstructure of the coating consists of an α-Fe matrix and Ti(C,N) particles when the mole ratio of Ti/g-C 3 N 4 is no more than 5:1. The microhardness and wear resistance of the coating gradually improve with increasing abundance of the in-situ-synthesized Ti(C,N) particles. Interestingly, for a Ti/g-C 3 N 4 mole ratio of 6:1, a fine lamellar eutectic Laves phase (Fe 2 Ti) appears, and this phase further improves the microhardness and wear resistance of the coating. The microhardness of the coating is 3.5 times greater than that of the Q235 substrate, and the wear resistance is enhanced 7.66 times over that of the substrate. The Ti(C,N)/Fe 2 Ti and Fe 2 Ti/α-Fe interfaces are very clean, and the crystallographic orientation relationships between the phases are analyzed by high-resolution transmission electron microscopy (HRTEM) and an edge-to-edge matching model. The theoretical predictions and the experimental results are in good agreement. Furthermore, based on the present study, for the solidification process near equilibrium, smaller interatomic spacing misfits and interplanar spacing d-value mismatches contribute to the formation of crystallographic orientation relationships between phases during the PTA cladding process. The existence of orientation relationships is beneficial for improving the properties of the coatings. This work not only expands the application fields of g-C 3 N 4 but also provides a new idea for the

  14. Resistance to High-Temperature Oxidation and Wear of Various Ferrous Alloys Used in Rolling Mills

    Science.gov (United States)

    Delaunois, Fabienne; Stanciu, Victor Ioan; Sinnaeve, Mario

    2018-01-01

    Various materials are commonly used to manufacture work rolls for hot rolling mills, such as ICDP (Indefinite Chill Double Pour) cast irons, high-chromium white cast irons, and high speed steels (HSS). Various chemical compositions and microstructures are studied in order to optimize the in-use behavior of those grades of rolls. In this paper, six grades of ferrous alloys (an ICDP cast iron; an ICDP cast iron enriched in vanadium, niobium, and molybdenum; a HSS; a graphitic HSS; a high-chromium white cast iron (Hi-Cr); and a niobium-molybdenum-doped high-chromium white cast iron) were investigated. High-temperature oxidation tests with gravimetric means at 575 °C in water vapor atmosphere and sliding wear tests were carried out. The oxidation kinetics was followed during oxidation test. The microstructure was observed by optical and scanning electron microscopies. The oxides formed on the surface of the samples were analyzed by XRD and EDS. The thickness of the oxide scales and the mass gain were measured after oxidation test. The results showed that the behavior of all the grades differed. The oxide scale of HSS and HSS-G grades was fine and their friction coefficient was low. The weight gain after oxidation test of HSS was high. Hi-Cr and M-Hi-Cr grades presented highly porous oxide layer and an important increase of the friction coefficient during wear test. ICDP and M-ICDP had intermediate behavior.

  15. Data-mining modeling for the prediction of wear on forming-taps in the threading of steel components

    Directory of Open Access Journals (Sweden)

    Andres Bustillo

    2016-10-01

    Full Text Available An experimental approach is presented for the measurement of wear that is common in the threading of cold-forged steel. In this work, the first objective is to measure wear on various types of roll taps manufactured to tapping holes in microalloyed HR45 steel. Different geometries and levels of wear are tested and measured. Taking their geometry as the critical factor, the types of forming tap with the least wear and the best performance are identified. Abrasive wear was observed on the forming lobes. A higher number of lobes in the chamber zone and around the nominal diameter meant a more uniform load distribution and a more gradual forming process. A second objective is to identify the most accurate data-mining technique for the prediction of form-tap wear. Different data-mining techniques are tested to select the most accurate one: from standard versions such as Multilayer Perceptrons, Support Vector Machines and Regression Trees to the most recent ones such as Rotation Forest ensembles and Iterated Bagging ensembles. The best results were obtained with ensembles of Rotation Forest with unpruned Regression Trees as base regressors that reduced the RMS error of the best-tested baseline technique for the lower length output by 33%, and Additive Regression with unpruned M5P as base regressors that reduced the RMS errors of the linear fit for the upper and total lengths by 25% and 39%, respectively. However, the lower length was statistically more difficult to model in Additive Regression than in Rotation Forest. Rotation Forest with unpruned Regression Trees as base regressors therefore appeared to be the most suitable regressor for the modeling of this industrial problem.

  16. The Abrasive Wear Resistance of the Segmented Linear Polyurethane Elastomers Based on a Variety of Polyols as Soft Segments

    Directory of Open Access Journals (Sweden)

    Konrad Kwiatkowski

    2017-12-01

    Full Text Available The presented results make an original contribution to the development of knowledge on the prediction and/or modeling of the abrasive wear properties of polyurethanes. A series of segmented linear polyurethane elastomers (PUR—In which the hard segments consist of 4,4′-methylene bis(phenylisocyanate and 1,4-butanodiol, whilst polyether, polycarbonate, or polyester polyols constitute the soft segments—Were synthesized and characterized. The hardness and wear performance as functions of the variable chemical composition of polyurethane elastomers were evaluated in order to define the relationship between studied factors. The microstructure was characterized in detail, including analysis of the hydrogen bonding by Fourier transformed infrared (FT-IR spectroscopy and the phase structure by X-ray scattering (WAXS and differential scanning calorimetry (DSC methods. The presented studies provide the key features of the polymer composition affecting the abrasive resistance as well as attempts to explain the origin of the differences in the polyurethane elastomers’ performance.

  17. Effect of Age-Hardening Treatment on Microstructure and Sliding Wear-Resistance Performance of WC/Cu-Ni-Mn Composite Coatings

    Science.gov (United States)

    Liu, Jun; Yang, Shuai; Liu, Kai; Gui, Chibin; Xia, Weisheng

    2017-06-01

    The Cu-Ni-Mn alloy-based hardfacing coatings reinforced by WC particles (WC/Cu-Ni-Mn) were deposited on a steel substrate by a manual oxy-acetylene weld hardfacing method. A sound interfacial junction was formed between the WC particles and the Cu-Ni-Mn alloy metal matrix binder even after the age-hardening treatment. The friction and wear behavior of the hardfacing coatings was investigated. With the introduction of WC particles, the sliding wear resistance of the WC/Cu-Ni-Mn hardfacing coatings was sharply improved: more than 200 times better than that of the age-hardening-treated Cu-Ni-Mn alloy coating. The sliding wear resistances of the as-deposited and the age-hardening-treated WC/Cu-Ni-Mn hardfacing coatings were 1.83 and 2.26 times higher than that of the commercial Fe-Cr-C hardfacing coating, which is mainly ascribed to the higher volume fraction of carbide reinforcement. Owing to the precipitation of the NiMn secondary phase in the Cu-Ni-Mn metal matrix, the age-hardening-treated coating had better wear resistance than that of the as-deposited coating. The main sliding wear mechanisms of the age-hardening-treated coatings are adhesion and abrasion.

  18. Anodized porous titanium coated with Ni-CeO{sub 2} deposits for enhancing surface toughness and wear resistance

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiaowei, E-mail: zhouxiaowei901@163.com; Ouyang, Chun

    2017-05-31

    Highlights: • Structural design of anodized nanoporous Ti was introduced for bonding pinholes to achieve a metallurgical bonding interface. • Anodized porous Ti substrate was activated by electroless Ni-P film to be acted as transitional layer to deposit Ni-CeO{sub 2} nanocomposite coatings. • An analytical model was validated for predicting the Ce-rich worn products as a self-lubricant phase for monitoring wear mechanisms. - Abstract: In order to make large improvements of surface toughness and wear resistance for pure titanium (Ti) substrate, anodic titanium oxide (ATO) surface with nanoporous structure was coated with the Ni-CeO{sub 2} nanocomposite coatings. Regarding TiO{sub 2} barrier layer on Ti surface to inhibit its electrochemical activity, pre-treatments were successively processed with anodizing, sensitizing, activating, and then followed by electroless Ni-P film to be acted as an activated layer for electroplating Ni-CeO{sub 2} deposits. The existing Pd atoms around ATO nanopores were expected as the heterogeneous nucleation sites for supporting the growing locations of electroless Ni-P film. The innovative of interface design using porous structure was introduced for bonding pinholes to achieve a metallurgical adhesion interface between Ti substrate and surface coatings. Besides the objectives of this work were to elucidate how effects by the adding CeO{sub 2} nanoparticles on modifying microstructures and wear mechanisms of Ni-CeO{sub 2} nanocomposite coatings. Many efforts of XRD, FE-SEM, TEM and Nanoindentation tests were devoted to comparing different wear behaviors of Ni-CeO{sub 2} coatings relative to pure nickel. Results indicated that uniform-distributed Ti nanopores with an average diameter size of ∼200 nm was achieved using the Phosphate-type anodizing solution at DC 150 V. A worn surface without fatigue cracks was observed for TAO surface coated with Ni-CeO{sub 2} deposits, showing the existing Ce-rich worn products to be acted as a

  19. Wear and Corrosion Resistance of CrN-based Coatings Deposited by R.F Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    K. Bouzid

    2015-03-01

    Full Text Available A comparative study was conducted to evaluate the performances against wear and corrosion of CrN, CrMoN, CrZrN, CrVN single layer thin films. The latest are synthesized onto steel substrates (DIN 90CrMoV8, using R.F reactive magnetron co-sputtering. The experimental work was achieved using ball-on-disc configuration in dry conditions against WC balls. The main conclusions are: (i electrochemical tests in 0.3 wt.% NaCl solution indicated that CrZrN are improved anticorrosion performance when compared to CrN, while CrMoN demonstrated a poor corrosion resistance;(ii the CrN coating presents the better tribological properties when compared to the ternary nitride coatings.

  20. Endurance in Al Alloy Melts and Wear Resistance of Titanium Matrix Composite Shot-Sleeve for Aluminum Alloy Die-casting

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Bong-Jae; Kim, Young-Jig [Sungkyunkwan University, Suwon (Korea, Republic of); Sung, Si-Young [Korea Automotive Technology Institute, Chonan (Korea, Republic of)

    2012-02-15

    The main purpose of this study was to evaluate the endurance against Al alloy melts and wear resistance of an in-situ synthesized titanium matrix composite (TMC) sleeve for aluminum alloy die-casting. The conventional die-casting shot sleeve material was STD61 tool steel. TMCs have great thermal stability, wear and oxidation resistance. The in-situ reaction between Ti and B4C leads to two kinds of thermodynamically stable reinforcements, such as TiBw and TiCp. To evaluate the feasibility of the application to a TMCs diecasting shot sleeve, the interfacial reaction behavior was examined between Al alloys melts with TMCs and STD61 tool steel. The pin-on-disk type dry sliding wear test was also investigated for TMCs and STD61 tool steel.

  1. In-situ electro-charging for friction reduction and wear resistant film formation

    Energy Technology Data Exchange (ETDEWEB)

    Tung, S.C.; Wang, S.S. (GM Research Laboratories, Warren, MI (USA))

    1991-10-01

    A technique has been developed to form friction-reducing and antiwear films in situ by means of an electric field applied between rubbing metal surfaces. Using this in situ charging technique, the effectiveness of zinc organodithiophosphate (ZDP) additives as antiwear and friction reducing agents can be enhanced by electrochemical reactions which form surface coatings. The coatings formed on sliding surfaces compared with uncharged surfaces reduce friction by up to 35 percent. In addition, during the sliding process, the films formed on the surfaces are replenished and protect the rubbing surfaces from wear. A steel plate subjected to rubbing and in situ charging for four hours had a smooth surface and a yellowish reaction film; the one without charging was rougher and no yellowish reaction film was formed. The improved tribological characteristics are attributed to an increase in the electrochemical reactivity of the ZDP-mineral oil blends and the formation of phosphate or sulfate films on the metal surfaces. 16 refs.

  2. Industrial scale HP-HT synthesis of hard and wear resistant c-Zr3N4

    Science.gov (United States)

    Dzivenko, Dmytro; Riedel, Ralf; Taniguchi, Takashi; Chauveau, Thierry; Zerr, Andreas

    2013-06-01

    We present a large scale high-pressure high-temperature (HP-HT) synthesis of hard and wear resistant cubic zirconium nitride having Th3P4-type structure,c-Zr3N4. This material, also available as well-adhesive coatings with exceptional wear resistance, represents a compound competitive to diamond and c-BN with respect to machining of low-carbon steels and other ferrous alloys. We obtained c-Zr3N4 powder at pressures as low as 6.5 GPa and temperatures of 1400-1600 °C from nanocrystalline Zr3N4+x precursor using a belt-type apparatus - a static HP-HT device widely employed for the commercial production of diamond and c-BN. The HP products are characterized in details by means of powder X-ray diffraction, Raman spectroscopy, scanning electron microscopy and combustion elemental analysis. In addition to major polycrystalline c-Zr3N4, we unveil the formation of a quaternary compound c-(Zr1-xTax)3 (N1-yOy)4 which indicates the possibility of doping of c-Zr3N4, thus introducing it for practical application as a multifunctional material. Moreover, we consider ways of cementing the c-Zr3N4 powders (similar to cemented tungsten carbides) which would allow economic fabrication of large bodies based on this compound. Supported by the DFG (Bonn, Germany) within SPP 1236 and by the IFR ``Paris Nord Plaine de France''.

  3. Hydrophobicity attainment and wear resistance enhancement on glass substrates by atmospheric plasma-polymerization of mixtures of an aminosilane and a fluorocarbon

    Science.gov (United States)

    Múgica-Vidal, Rodolfo; Alba-Elías, Fernando; Sainz-García, Elisa; Pantoja-Ruiz, Mariola

    2015-08-01

    Mixtures of different proportions of two liquid precursors were subjected to plasma-polymerization by a non-thermal atmospheric jet plasma system in a search for a coating that achieves a hydrophobic character on a glass substrate and enhances its wear resistance. 1-Perfluorohexene (PFH) was chosen as a low-surface-energy precursor to promote a hydrophobic character. Aminopropyltriethoxysilane (APTES) was chosen for its contribution to the improvement of wear resistance by the formation of siloxane bonds. The objective of this work was to determine which of the precursors' mixtures that were tested provides the coating with the most balanced enhancement of both hydrophobicity and wear resistance, given that coatings deposited with fluorocarbon-based precursors such as PFH are usually low in resistance to wear and coatings deposited with APTES are generally hydrophilic. The coatings obtained were analyzed by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infra-Red (FTIR) spectroscopy, X-ray Photoelectron Spectroscopy (XPS), static Water Contact Angle (WCA) measurements, tribological ball-on-disc tests and contact profilometry. A relationship between the achievement of a hydrophobic character and the modifications to roughness and surface morphology and the incorporation of fluorocarbon groups in the surface chemistry was observed. Also, it was seen that the wear resistance was influenced by the SiOSi content of the coatings. In turn, the SiOSi content appears to be directly related to the percentage of APTES used in the mixture of precursors. The best conjunction of hydrophobicity and wear resistance in this work was found in the sample that was coated using a mixture of APTES and PFH in proportions of 75 and 25%, respectively. Its WCA (100.2 ± 7.5°) was the highest of all samples that were measured and more than three times that of the uncoated glass (31 ± 0.7°). This sample underwent a change from a hydrophilic to a

  4. Detection of Resistive Transitions in LHC Superconducting Components

    CERN Document Server

    Denz, R

    2001-01-01

    The LHC has entered the construction phase. It will incorporate a large number of superconducting components like magnets, current leads and busbars. All these components require protection means in case of a transition from the superconducting to the resistive state, the so-called quench. Key elements in the protection system are electronic quench detectors, which have to be able to identify a quench in any state of the powering cycle of the accelerator. According to the different properties and characteristics of the superconducting elements and circuits, a set of quench detectors adapted to their specific tasks has been developed.

  5. Polymer wear evaluation

    DEFF Research Database (Denmark)

    Lagerbon, Mikkel; Sivebæk, Ion Marius

    2012-01-01

    Polymer wear plays an increasing role in manufacturing of machine parts for e.g. medical devices. Some of these have an expected lifetime of five to eight years during which very little wear of the components is acceptable. Too much wear compromises the dosage accuracy of the device and thereby...... the safety of the patients. Prediction of the wear of polymers is complicated by the low thermal conductivity of this kind of material. It implies that any acceleration of testing conditions by increased contact pressure and/or sliding velocity will make the polymer fail due to exaggerated heat buildup....... This is not the kind of wear observed in medical devices. In the present work a method was developed capable of evaluating the wear progression in polymer-polymer contacts. The configuration of the setup is injection moulded specimens consisting of an upper part having a toroid shape and a lower flat part. The sliding...

  6. Scanning velocity influence on microstructure, microhardness and wear resistance performance of laser deposited Ti6Al4V/TiC composite

    CSIR Research Space (South Africa)

    Mahamood, RM

    2013-09-01

    Full Text Available Ti6Al4V is the most widely used titanium alloy in the aerospace industry because of its excellent properties. However, the wear resistance behaviour of this material is not very impressive and surface damage occurs in applications involving contact...

  7. Effect of high-manganese cast steel strain hardening on the abrasion wear resistance in a mixture of SiC and water

    Directory of Open Access Journals (Sweden)

    Kalandyk B.

    2013-12-01

    Full Text Available The study attempts to determine the impact of the high-manganese cast steel strain hardening on its abrasion wear resistance in a mixture of SiC and water prepared in accordance with ASTM G75. For tests, the high-manganese cast steel containing 10.7, 17.9 and 20.02% Mn was selected. The results of microstructure examinations and abrasion wear resistance tests carried out on the material in non-hardened condition and after strain hardening with a force of 539.55kN were disclosed. Additionally, the surface of samples after a 16-hour cycle of abrasion tests was examined. Moreover, based on the obtained results, the effect of different contents of Mn in cast steel was studied, mainly in terms of its impact on the abrasion wear resistance. The results obtained on the tested materials were compared with the results obtained on the low-alloyed abrasion wear-resistant cast steel L35GSM.

  8. Effect of pressing temperature on the wear resistance of a Co-based Cr-Mo powder alloy produced by hot pressing

    Energy Technology Data Exchange (ETDEWEB)

    Somunkiran, Ilyas [Firat Univ., Elazig (Turkey). Metallurgical and Materials Engineering Dept.; Balin, Ahmet [Siirt Univ. (Turkey). Dept. of Vocational High School

    2016-02-01

    In this study, Co-based Cr-Mo powder alloy was produced at different pressing temperatures by using hot pressing technique and abrasive wear behaviors of the produced specimens were examined. Produced specimens were exposed to abrasive wear experiment using block on disc wear test device by applying a load of 50 N with 100-mesh SiC abrasive paper. Each specimen was investigated at 25, 50, 75 and 100 m. At the end of the experiment, abrasive wear results of the specimens were determined by calculating their mass losses. Microstructural properties of the specimens which were produced at different pressing temperatures were investigated by optical and SEM examinations and their wear resistances were examined by abrasive wear experiments. Consequently, it was observed that in Co-based Cr-Mo powder alloy produced by hot pressing technique; as sintering temperature increased, size of neck formations between the powder grains increased, porosity decreased and abrasive wear resistance increased. [German] In diesem Beitrag zugrunde liegenden Studie wurde eine Co-basierte Cr-Mo-Legierung mittels Heisspressens hergestellt und der Abrasivverschleisswiderstand dieser Proben untersucht. Die hergestellten Proben wurden dem Abrasivverschleissversuch durch einen Block-Scheibe-Versuchsaufbau unterzogen, wobei eine Kraft von 50 N mit einem SiC-Papier (100 mesh) verwendet wurde. Jede Probe wurde ueber eine Distanz von 25, 50, 75 und 100 m untersucht. Am Ende der jeweiligen Experimente wurden die Abrasivverschleissergebnisse ermittelt, indem die Massenverluste berechnet wurden. Die mikrostrukturellen Eigenschaften der Proben, die bei verschiedenen Presstemperaturen hergestellt wurden, wurden mittels optischer und Rasterelektronenmikroskopie bestimmt und ihr Verschleisswiderstand anhand der Verschleissversuche ermittelt. Schliesslich wurde beobachtet, dass bei steigender Sintertemperatur der heissgespressten Co-basierten Cr-Mo-Pulverlegierung die Groesse der Einschnuerungen zwischen den

  9. Microstructure and wear resistance of laser cladded Ni-Cr-Co-Ti-V high-entropy alloy coating after laser remelting processing

    Science.gov (United States)

    Cai, Zhaobing; Cui, Xiufang; Liu, Zhe; Li, Yang; Dong, Meiling; Jin, Guo

    2018-02-01

    An attempt, combined with the technologies of laser cladding and laser remelting, has been made to develop a Ni-Cr-Co-Ti-V high entropy alloy coating. The phase composition, microstructure, micro-hardness and wear resistance (rolling friction) were studied in detail. The results show that after laser remelting, the phase composition remains unchanged, that is, as-cladded coating and as-remelted coatings are all composed of (Ni, Co)Ti2 intermetallic compound, Ti-rich phase and BCC solid solution phase. However, after laser remelting, the volume fraction of Ti-rich phase increases significantly. Moreover, the micro-hardness is increased, up to ∼900 HV at the laser remelting parameters: laser power of 1 kW, laser spot diameter of 3 mm, and laser speed of 10 mm/s. Compared to the as-cladded high-entropy alloy coating, the as-remelted high-entropy alloy coatings have high friction coefficient and low wear mass loss, indicating that the wear resistance of as-remelted coatings is improved and suggesting practical applications, like coatings on brake pads for wear protection. The worn surface morphologies show that the worn mechanism of as-cladded and as-remelted high-entropy alloy coatings are adhesive wear.

  10. Synthesis of High-Temperature Self-lubricating Wear Resistant Composite Coating on Ti6Al4V Alloy by Laser Deposition

    Science.gov (United States)

    Luo, Jian; Liu, Xiu-Bo; Xiang, Zhan-Feng; Shi, Shi-Hong; Chen, Yao; Shi, Gao-Lian; Wu, Shao-Hua; Wu, Yu-Nan

    2015-05-01

    Laser deposition was adopted to prepare novel Ni-based solid solution (γ-NiCrAlTi)/ TiC/α-Ti/CaF2 high-temperature self-lubricating wear resistant composite coating on Ti6Al4V alloy. Microstructure, micro-hardness, wear behavior, and counter-body effect of the coating were investigated systematically. It can be seen that the coating mainly consists of γ-NiCrAlTi, TiC, α-Ti, and small fine CaF2 particles. Average micro-hardness of the coating is 1023 HV0.3, which is about three-factor higher than that of Ti6Al4V substrate (380 HV0.3). The friction coefficient and wear rate of the coating decrease at all test temperatures to different extents with respect to the substrate. The improvement in wear resistance is believed to be the combined effects of the γ-NiCrAlTi solid solution, the dominating anti-wear capabilities of the reinforced TiC carbides, and the self-lubricating property of CaF2.

  11. Effect of deep cryogenic treatment and tempering on microstructure and mechanical behaviors of a wear-resistant austempered alloyed bainitic ductile iron

    Directory of Open Access Journals (Sweden)

    Chen Liqing

    2015-01-01

    Full Text Available In this paper, the effect of deep cryogenic treatment in combination with conven- tional heat treatment process was investigated on microstructure and mechanical behaviors of alloyed bainitic ductile iron. Three processing schedules were employed to treat this alloyed ductile iron including direct tempering treatment, tempering.+deep cryogenic treatment and deep cryogenic treatment.+tempering treatments. The microstructure and mechanical behavior, especially the wear resistance, have been evaluated after treated by these three schedules. The results show that martensite microstructure can be obviously refined and the precipitation of dispersed carbides is promoted by deep cryogenic treatment at .−196 ∘C for 3 h after tempered at 450 ∘C for 2 h. In this case, the alloyed bainitic ductile iron possesses rather high hardness and wear-resistance than those processed by other two schedules. The main wear mechanism of the austempered alloyed ductile iron with deep cryogenic treatment and tempering is micro-cutting wear in association with plastic deformation wear.

  12. Micro-EDM process modeling and machining approaches for minimum tool electrode wear for fabrication of biocompatible micro-components

    DEFF Research Database (Denmark)

    Puthumana, Govindan

    2017-01-01

    Micro-electrical discharge machining (micro-EDM) is a potential non-contact method for fabrication of biocompatible micro devices. This paper presents an attempt to model the tool electrode wear in micro-EDM process using multiple linear regression analysis (MLRA) and artificial neural networks...... linear regression model was developed for prediction of TWR in ten steps at a significance level of 90%. The optimum architecture of the ANN was obtained with 7 hidden layers at an R-sq value of 0.98. The predicted values of TWR using ANN matched well with the practically measured and calculated values...... (ANN). The governing micro-EDM factors chosen for this investigation were: voltage (V), current (I), pulse on time (Ton) and pulse frequency (f). The proposed predictive models generate a functional correlation between the tool electrode wear rate (TWR) and the governing micro-EDM factors. A multiple...

  13. Creep behavior and wear resistance of Al 5083 based hybrid composites reinforced with carbon nanotubes (CNTs) and boron carbide (B{sub 4}C)

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, Ali [Faculty of Materials & Manufacturing Processes, Malek-e-Ashtar University of Technology, Tehran (Iran, Islamic Republic of); Abdollahi, Alireza, E-mail: alirezaabdollahi1366@gmail.com [Faculty of Materials & Manufacturing Processes, Malek-e-Ashtar University of Technology, Tehran (Iran, Islamic Republic of); Biukani, Hootan [Faculty of Engineering, South Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2015-11-25

    In the current research, aluminum based hybrid composite reinforced with boron carbide (B{sub 4}C) and carbon nanotubes (CNTs) was produced by powder metallurgy method. creep behavior, wear resistance, surface roughness, and hardness of the samples were investigated. To prepare the samples, Al 5083 powder was milled with boron carbide particles and carbon nanotubes using planetary ball mill under argon atmosphere with ball-to-powder weight ratio of 10:1 for 5 h. Afterwards, the milled powders were formed by hot press process at 380{sup °}C and then were sintered at 585{sup °}C under argon atmosphere for 2 h. There was shown to be an increase in hardness values of composite with an increase in B{sub 4}C content. The micrograph of worn surfaces indicate a delamination mechanism due to the presence of CNTs and abrasion mechanism in composite containing 10 vol.%B{sub 4}C. Moreover, it was shown that increasing B{sub 4}C content increases the wear resistance by 3 times under a load of 20 N and 10 times under a load of 10 N compared to CNTs-reinforced composite. surface roughness of the composite containing 5 vol.%CNT has shown to be more than other samples. The results of creep test showed that adding carbon nanotubes increases creep rate of Al 5083 alloy; however, adding B{sub 4}C decreases its creep rate. - Highlights: • Al 5083/(CNTs + B{sub 4}C) hybrid composite was produced by powder metallurgy method. • Creep behavior, wear resistance, surface roughness, and Hardness of samples were investigated. • Addition of CNTs to Al 5083 matrix reduces alloy hardness, wear resistance and creep strength. • By addition of B{sub 4}C and composite hybridization, creep strength and wear resistance increased. • Surface roughness of Al-5 vol.%CNT has shown to be more than other samples.

  14. Facile and scalable preparation of highly wear-resistance superhydrophobic surface on wood substrates using silica nanoparticles modified by VTES

    Science.gov (United States)

    Jia, Shanshan; Liu, Ming; Wu, Yiqiang; Luo, Sha; Qing, Yan; Chen, Haibo

    2016-11-01

    In this study, an efficient, facile method has been developed for fabricating superhydrophobic surfaces on wood substrates using silica nanoparticles modified by VTES. The as-prepared superhydrophobic wood surface had a water contact angle of 154° and water slide angle close to 0°. Simultaneously, this superhydrophobic wood showed highly durable and robust wear resistance when having undergone a long period of sandpaper abrasion or being scratched by a knife. Even under extreme conditions of boiling water, the superhydrophobicity of the as-prepared wood composite was preserved. Characterizations by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy showed that a typical and tough hierarchical micro/nanostructure was created on the wood substrate and vinyltriethoxysilane contributed to preventing the agglomeration of silica nanoparticles and serving as low-surface-free-energy substances. This superhydrophobic wood was easy to fabricate, mechanically resistant and exhibited long-term stability. Therefore, it is considered to be of significant importance in the industrial production of functional wood, especially for outdoor applications.

  15. 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

  16. Page 1 Deposition of Ni-B composites 32.5 The wear resistance of ...

    Indian Academy of Sciences (India)

    The corrosion resistance was evaluated by counting the number of rust spots, seen at low magnification, on the sample immersed in 3% sodium chloride solution for 24hr. 3. Results. 3.1 Deposit composition. The nickel deposits formed by chemical reduction with sodium borohydride are alloys of nickel and boron. Nickel ...

  17. Enhancement of wear and corrosion resistance of low modulus β-type Zr-20Nb-xTi (x=0, 3) dental alloys through thermal oxidation treatment.

    Science.gov (United States)

    Zhang, Jianfeng; Gan, Xiaxia; Tang, Hongqun; Zhan, Yongzhong

    2017-07-01

    In order to obtain material with low elastic modulus, good abrasion resistance and high corrosion stability as screw for dental implant, the biomedical Zr-20Nb and Zr-20Nb-3Ti alloy with low elastic modulus were thermal oxidized respectively at 700°C for 1h and 600°C for 1.25h to obtain the compact oxidized layer to improve its wear resistance and corrosion resistance. The results show that smooth compact oxidized layer (composed of monoclinic ZrO 2 , tetragonal ZrO 2 and 6ZrO 2 -Nb 2 O 5 ) with 22.6μm-43.5μm thickness and 1252-1306HV hardness can be in-situ formed on the surface of the Zr-20Nb-xTi (x=0, 3). The adhesion of oxidized layers to the substrates is determined to be 58.35-66.25N. The oxidized Zr-20Nb-xTi alloys reveal great improvement of the pitting corrosion resistance in comparison with the un-oxidized alloys. In addition, the oxidized Zr-20Nb-3Ti exhibits sharply reduction of the corrosion rates and the oxidized Zr-20Nb shows higher corrosion rates than un-oxidized alloys, which is relevant with the content of the t-ZrO 2 . Wear test in artificial saliva demonstrates that the wear losses of the oxidized Zr-20Nb-xTi (x=0, 3) are superior to pure Ti. All of the un-oxidized Zr-20Nb-xTi (x=0, 3) alloys suffer from serious adhesive wear due to its high plasticity. Because of the protection from compact oxide layer with high adhesion and high hardness, the coefficients of friction and wear losses of the oxidized Zr-20Nb-xTi (x=0, 3) alloys decrease 50% and 95%, respectively. The defects on the oxidized Zr-20Nb have a negative effect on the friction and wear properties. In addition, after the thermal oxidation, compression test show that elastic modulus and strength of Zr-20Nb-xTi (x=0, 3) increase slightly with plastic deformation after 40% of transformation. Furthermore, stripping of the oxidized layer from the alloy matrix did not occur during the whole experiments. As the surface oxidized Zr-20Nb-3Ti alloy has a combination of excellent performance

  18. Effect of In-Office Carbamide Peroxide-Based Tooth Bleaching System on Wear Resistance of Silorane-Based and Methacrylate-Based Dental Composites

    Directory of Open Access Journals (Sweden)

    Masoumeh Hasani Tabatabaei

    2016-04-01

    Full Text Available Objectives: Several studies have assessed the characteristics and properties of silorane-based composites and adhesive systems. Considering the extensive application of tooth-whitening agents, possible deteriorative effects of tooth bleaching agents on these restorative materials must be studied. The aim of this study was to evaluate the effect of an in-office carbamide peroxide-based tooth bleaching agent on the wear resistance of a silorane-based and a conventional microhybrid dimethyl methacrylate-based dental composite with two different application times.  Materials and Methods: Thirty cylindrical specimens were made of Z250 and P90 dental composite resins (n=15 for each composite. Samples made of each composite were divided into three groups (n=5 for immersion in an in-office bleaching agent (Opalescence® Quick 45% for either three or eight hours or saline solution (control. Wear tests were conducted after bleaching using a pin-on disk apparatus under the load of 40N at a constant sliding speed of 0.5 ms-1 for a sliding distance of 300 m. The samples were weighed before and after the wear test. Repeated measures ANOVA was used to statistically analyze the obtained data (α=0.05.Results: There was a significant decrease in the weight of samples after the wear test (P<0.001. However, no significant difference was found among groups in the mean weight of samples before and after the wear test (P>0.05. Conclusion: Bleaching for three or eight hours using 45% carbamide peroxide had no deteriorative effect on the wear resistance of Z250 and P90 composites.

  19. Wear of components in consumer substation caused by high differential pressure; Slitage av komponenter i FC orsakade av hoega differenstryck

    Energy Technology Data Exchange (ETDEWEB)

    Fransson, Anders [Goeteborg Energi AB (Sweden)

    2005-07-01

    The purpose of this project was to show the consequences in increased wear and decreased lowering of the return temperature in sub stations as a result of changes in the production of district heating, in particular increased differential pressure. It is known that increased differential pressure might lead to; - Noise - Ascending return temperature - Unwanted descending temperatures on the secondary side (i.e. the hot water circuit and the radiator circuit) - Oscillating regulation - Increased wear of the control equipment - Leakage from old heat exchangers There are four areas with in the district heating grid of Goeteborg Energi AB that are studied according to reported faults. Noise: The area which has the highest differential pressure and known variation in differential pressure also has the most problem. It is not possible to make certain statements based on the study. Ascending return temperature: Both areas with higher differential pressure reveals decreased cooling of the primary water and higher overconsumption of primary water according to the principle of overconsumption relatively the other two areas. Unwanted descending temperatures on the secondary side (i.e. the hot water circuit and the radiator circuit) This fault is not found in the study. Oscillating regulation: This fault is not found in the study. Increased wear of the control equipment: The area which has the highest differential pressure also has most problems with wear. Looking at leakage from packing boxes, you will also see a clear effect over time. It is still not possible to make certain statements based on the study. Valves and sometimes the corresponding actuators have been replaced because they were oversized. It is impossible to exclude those replacements completely from the material in the study. Leakage from old heat exchangers: This fault is not found in the study. However it is found more common to find leakage to the surroundings in the areas with higher differential pressure

  20. Improving hardness and wear resistance of austenitic stainless steel; Harte und verschleissfeste Randschicht auf korrosionsbestaendigen Staehlen

    Energy Technology Data Exchange (ETDEWEB)

    Guempel, Paul [Hochschule Konstanz (Germany). Werkstoffprueflabor; Waegner, Martina [Bodycote Hardiff GmbH, Huerth (Germany). S3P-Gruppe

    2010-09-15

    Nowadays more stainless steels are used in the field of automotive technology. These austenitic or ferritic steels have a high corrosion resistance but they are not hardenable and therefore they are susceptible to gallig / fretting during mechanical / tribological loading, for example in connecting rods. With a new surface hardening treatment these detrimental effects can be avoided. Hochschule Konstanz and Bodycote jointly develop this process further to open up new market areas. (orig.)

  1. Evaluation of permanent die coatings to improve the wear resistance of die casting dies. Final project report, January 1, 1995--April 30, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Shivpuri, R.

    1997-09-18

    Die Casting dies are subject to severe service conditions during the die casting operation. While these severe conditions are necessary to achieve high production rates, they cause the dies which are commonly made of H13 die steel, to suffer frequent failures. The major die failure mechanisms are erosion or washout, Heat checking, soldering and corrosion. Due to their geometrical complexity, die casting dies are very expensive (some dies cost over a million dollars), and thus a large number of parts have to be produced by a die, to justify this cost and leverage the advantages of the die casting process (high production rates, low manpower costs). A potential increase in the die service life, thus has a significant impact on the economics of the die; casting operation. There are many ways to extend die life: developing new wear resistant die materials, developing new surface treatments including coatings, improving heat treatment of existing H13 dies, using better lubricants that can protect the die material, or modifying the die geometry and process parameters to reduce the intensity of wear. Of these the use of coatings to improve the wear resistance of the die surface has shown a lot of promise. Consequently, use of coatings in the die casting industry and their wide use to decrease die wear can improve significantly the productivity of shop operations resulting in large savings in material and energy usage.

  2. Microstructures and tribological properties of plasma sprayed WC-Co-Cu-BaF 2/CaF 2 self-lubricating wear resistant coatings

    Science.gov (United States)

    Yuan, Jianhui; Zhu, Yingchun; Ji, Heng; Zheng, Xuebing; Ruan, Qichao; Niu, Yaran; Liu, Ziwei; Zeng, Yi

    2010-06-01

    A promising WC-Co-Cu-BaF 2/CaF 2 self-lubricating wear resistant coating was deposited via atmospheric plasma spraying (APS) process by using homemade feedstock powders composed of WC-Co, Cu and BaF 2/CaF 2 eutectic. The as-prepared cermet coatings had better frictional behavior comparing with the WC-Co coating. Moreover, the often-occurred decarburization of WC in APS process was noticeably improved due to the binding of copper and BaF 2/CaF 2 phase, which not only offered effective solid lubrication, but also acted as bind phases to mend the microstructure and protected WC from decomposition. The optimized specimen contained 10 wt.% Cu and 10 wt.% BaF 2/CaF 2 in a WC-Co matrix, which had excellent frictional and wear performance. The wear mechanism of the self-lubricating wear resistant coating was discussed with the microstructures, compositions and mechanical properties of the composite materials in detail.

  3. ELECTROCHEMICAL METHODS TO IMPROVE THE WEAR RESISTANCE OF COATING DEPOSITED ON THE METAL SURFACE

    Directory of Open Access Journals (Sweden)

    Yurij Shalapko

    2015-09-01

    Full Text Available It was established that existing methods show low accuracy when assessing the durability of coatings. Furthermore, they don’t allow assessment of the contribution into durability of structural components and fillers for thermodiffusion and polymer-composite coatings, respectively. A method to evaluate durability of thermal diffusion chrome coatings on carbon steel and gray cast irons has been developed - the speed υp of destruction of the structural components of the coating. In addition, the destruction of each structural component is characterized by a constant value of destruction speed υp and potential φ, and their sharp vibrations are in complete destruction of the coating and the beginning of the destruction of the base metal. From the start of the test until the abrupt change in the rate of destruction υp, which is found on the curve υp - τ is the assessment of durability coating t¶ hat is specified with the curve φ - τ. Accuracy of the durability decreases from ± 30 min to ± 2 min. Developed as a way to assess the durability fillers polymer composite coatings, along with the finding that the rate of destruction υp of the time includes total disability coverage t3aƧ and time breakdown cover τn which are fixed on the curve φ - τ.

  4. Determinación del desgaste del componente acetabular en prótesis totales de cadera. // Wear determination of acetabular component in total hip prosthesis.

    Directory of Open Access Journals (Sweden)

    G. García del Pino

    2002-01-01

    Full Text Available En este trabajo se realiza un estudio a través del Método de los Elementos Finitos “MEF” sobre el desgaste del componenteacetabular durante el ciclo de marcha y considerando algunos casos extremos de cargas como subir y bajar escaleras,levantarse de una silla, etc. Utilizando el MEF fueron modelados independientemente los componentes acetabular yfemoral de la prótesis total de cadera y puestos en contacto posteriormente. Fueron estudiadas varias posiciones delacetábulo así como diferentes casos de carga simulando pacientes con diferente peso corporal y actividades físicas. Paraevaluar los resultados se crearon rutinas en lenguaje C que organizaron los mismos para un tratamiento estadísticoposterior.Palabras claves: biomecánica, ortopedia, elementos finitos, modelación, desgaste, prótesis de cadera.___________________________________________________________________________Abstract.A wear study of acetabular component during the marching cycle, considering some extreme loads cases as: ascend anddescend stairways, get up from a seat, etc , by means of Finite Elements Method ( FEM , is carried out. The acetabular andfemoral component of the total hip prosthesis were independently modeled and placed in contact lastly. Several acetabulpositions were studied as well as different load cases, simulating patients with different body weight and different physicalactivities. To evaluate the results routines in C language were created in order to organized the same ones for a laterstatistical treatment.Key words. biomechanics, ortophedy, finite elements, modelation, wear, hip bone prosthesis.

  5. Development of low-friction and wear-resistant surfaces for low-cost Al hot stamping tools

    Directory of Open Access Journals (Sweden)

    Dong Y.

    2015-01-01

    Full Text Available In this study, advanced surfaces and coatings have been developed using plasma thermochemical treatment, PVD coating, electroless Ni-BN plating and duplex surface engineering to produce low-friction and wear-resistant surfaces for cast iron stamping tools. Their microstructural and nano-mechanical properties were systematically analysed and the tribological behaviour of these new surfaces and coatings were evaluated. The experimental results have shown that under dry sliding condition, the tribological behaviour of aluminium differed great from that of steel regardless of the counterpart material. Highly reactive aluminium had a strong tendency to solder with tool surfaces during dry sliding. However, the lubricity of gray cast irons can be significantly improved by Ni-BN and DLC coatings. The coefficient of friction reduced from about 0.5 for untreated cast irons to about 0.2 sliding against aluminium. Duplex treatment combining plasma nitrocarburising with low-friction coatings showed superior durability than both DLC and Ni-BN coatings.

  6. Effects of Heat-Treatment on the Microstructure and Wear Resistance of a High-Chromium Cast Iron for Rolls

    Directory of Open Access Journals (Sweden)

    Zhi-hong Guo

    2016-01-01

    Full Text Available The variations of microstructure and mechanical properties of a high-chromium cast iron for rolls were studied from as-cast to the final heat treatments. Results show that the as-cast microstructure of the HCCI consists of M7C3 carbide, M23C6 carbide, martensite matrix, and retained austenite. The large dendritic M7C3 carbide surrounds the matrix, and the M23C6 carbide is mainly distributed in the matrix. Part of M23C6 carbide transforms to M7C3 carbide and is dissolved in austenite during austenization at 1020°C. Thus, the amount of M23C6 carbide decreases, whereas that of M7C3 carbide increases after quenching; the highest hardness is also obtained. After tempering, the martensite transforms to a tempered martensite, and some carbide precipitates in the martensite matrix. The hardness also changes from HRC62.1, which corresponds to quenching, to HRC55.2 and HRC56.3, which correspond to once and twice tempering, respectively. However, tempering could improve the impact toughness and wear resistance of the HCCI.

  7. How do material properties influence wear and fracture mechanisms?

    Science.gov (United States)

    Rimnac, Clare; Pruitt, Lisa

    2008-01-01

    The wear and fracture mechanisms of ultra-high-molecular-weight polyethylene (UHMWPE) hip and knee implant components are of great interest. The material properties of UHMWPE are affected by ionizing radiation as used for sterilization and cross-linking. Cross-linking with high-dose irradiation has been shown to improve the wear resistance of UHMWPE. However, cross-linking leads to a loss in properties such as ductility and resistance to fatigue crack propagation. Highly cross-linked UHMWPE may be more susceptible than conventional UHMWPE to fracture under severe clinical conditions (eg, impingement). Contemporary hip and knee simulator studies provide good information with which new UHMWPE formulations can be screened for clinical wear performance. However, comparable methodologies are lacking for screening UHMWPEs for fracture resistance. Mechanical tests as well as computational material and structural models should be developed to evaluate the combined effect of material and geometry (structure) on fracture resistance under clinically relevant loading conditions.

  8. DIFFUSIVELY ALLOYED COMPOUNDS MADE OF METAL DISCARD WITH A REDUCED MELTING TEMPERATURE FOR OBTAINING WEAR RESISTANT COATINGS USING INDUCTION HARD-FACING TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    V. G. Shcherbakou

    2016-01-01

    Full Text Available The technology of obtaining diffusion doped alloys made from metal scrap is reviewed in the article. The influence of short term preprocessing at high temperature on structure formation by concentrated energy sources within the further induction deposit is reviewed. A mechanism of a contact eutectic melting in diffusion doped alloys at short term high temperature treatment is described and suggested in this work. It was shown that such kind of processing of diffusion doped alloys is a perspective way of treatment when using induction hard-facing technologies for obtaining wear resistant coatings. A resource and energy saving technology was developed for obtaining wear resistant coatings based on diffusion doped alloys from metal scrap treated using induction hard-facing process.

  9. Effects of the different frequencies and loads of ultrasonic surface rolling on surface mechanical properties and fretting wear resistance of HIP Ti–6Al–4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Li, G., E-mail: ligang_scut@outlook.com; Qu, S.G., E-mail: qusg@scut.edu.cn; Pan, Y.X.; Li, X.Q.

    2016-12-15

    Highlights: • Effects of MUSR frequency and load on surface properties of HIP Ti-6Al-4V investigated. • The grains in surface-modified layer were refined and appeared twins and many dense dislocations. • The hardened layer depth and surface residual stress of MUSR- treated samples were significantly improved. • MUSR- treated samples showed the good fretting friction and wear resistance. • The best microstructure and properties of surface-modified layer obtained by sample treated by 30 kHz and 900 N. - Abstract: The main purpose of this paper was to investigate the effects of the different frequencies and loads of multi-pass ultrasonic surface rolling (MUSR) on surface layer mechanical properties, microstructure and fretting friction and wear characteristics of HIP (hot isostatic pressing) Ti–6Al–4 V alloy. Some microscopic analysis methods (SEM, TEM and EDS) were used to characterize the modified surface layer of material after MUSR treatment. The results indicated that the material in sample surface layer experienced a certain extent plastic deformation, and accompanied by some dense dislocations and twins generation. Moreover surface microhardness and residual stress of samples treated by MUSR were also greatly improved compared with the untreated. The fretting friction and wear properties of samples treated by MUSR in different conditions are tested at 10 and 15 N in dry friction conditions. It could be found that friction coefficient and wear volume loss were significantly declined in the optimal result. The main wear mechanism of MUSR-treated samples included abrasive wear, adhesion and spalling.

  10. High performance corrosion and wear resistant composite titanium nitride layers produced on the AZ91D magnesium alloy by a hybrid method

    Directory of Open Access Journals (Sweden)

    Michał Tacikowski

    2014-09-01

    Full Text Available Composite, diffusive titanium nitride layers formed on a titanium and aluminum sub-layer were produced on the AZ91D magnesium alloy. The layers were obtained using a hybrid method which combined the PVD processes with the final sealing by a hydrothermal treatment. The microstructure, resistance to corrosion, mechanical damage, and frictional wear of the layers were examined. The properties of the AZ91D alloy covered with these layers were compared with those of the untreated alloy and of some engineering materials such as 316L stainless steel, 100Cr6 bearing steel, and the AZ91D alloy subjected to commercial anodizing. It has been found that the composite diffusive nitride layer produced on the AZ91D alloy and then sealed by the hydrothermal treatment ensures the corrosion resistance comparable with that of 316L stainless steel. The layers are characterized by higher electrochemical durability which is due to the surface being overbuilt with the titanium oxides formed, as shown by the XPS examinations, from titanium nitride during the hydrothermal treatment. The composite titanium nitride layers exhibit high resistance to mechanical damage and wear, including frictional wear which is comparable with that of 100Cr6 bearing steel. The performance properties of the AZ91D magnesium alloy covered with the composite titanium nitride coating are substantially superior to those of the alloy subjected to commercial anodizing which is the dominant technique employed in industrial practice.

  11. Enhancing Corrosion and Wear Resistance of AA6061 by Friction Stir Processing with Fe78Si9B13 Glass Particles

    Directory of Open Access Journals (Sweden)

    Lingyu Guo

    2015-08-01

    Full Text Available The AA6061-T6 aluminum alloy samples including annealed Fe78Si9B13 particles were prepared by friction stir processing (FSP and investigated by various techniques. The Fe78Si9B13-reinforced particles are uniformly dispersed in the aluminum alloy matrix. The XRD results indicated that the lattice parameter of α-Al increases and the preferred orientation factors F of (200 plane of α-Al reduces after friction stir processing. The coefficient of thermal expansion (CTE for FSP samples increases at first with the temperature but then decreases as the temperature further increased, which can be explained by the dissolving of Mg and Si from β phase and Fe78Si9B13 particles. The corrosion and wear resistance of FSP samples have been improved compared with that of base metal, which can be attributed to the reduction of grain size and the CTE mismatch between the base metal and reinforced particles by FSP, and the lubrication effect of Fe78Si9B13 particles also plays a role in improving wear resistance. In particular, the FSP sample with reinforced particles in amorphous state exhibited superior corrosion and wear resistance due to the unique metastable structure.

  12. Tribo-Mechanical Properties of HVOF Deposited Fe3Al Coatings Reinforced with TiB2 Particles for Wear-Resistant Applications

    Directory of Open Access Journals (Sweden)

    Mahdi Amiriyan

    2016-02-01

    Full Text Available This study reveals the effect of TiB2 particles on the mechanical and tribological properties of Fe3Al-TiB2 composite coatings against an alumina counterpart. The feedstock was produced by milling Fe3Al and TiB2 powders in a high energy ball mill. The high-velocity oxy-fuel (HVOF technique was used to deposit the feedstock powder on a steel substrate. The effect of TiB2 addition on mechanical properties and dry sliding wear rates of the coatings at sliding speeds ranging from 0.04 to 0.8 m·s−1 and loads of 3, 5 and 7 N was studied. Coatings made from unreinforced Fe3Al exhibited a relatively high wear rate. The Vickers hardness, elastic modulus and wear resistance of the coatings increased with increasing TiB2 content in the Fe3Al matrix. The wear mechanisms strongly depended on the sliding speed and the presence of TiB2 particles but were less dependent on the applied load.

  13. DIFFUSION COATINGS FOR CORROSION RESISTANT COMPONENTS IN COAL GASIFICATION SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2005-01-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy may improve is resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this reporting period we coated coupons of selected alloy steels with diffusion coatings of Cr and Al, as well as with titanium and tantalum nitrides. The coated samples were analyzed for their surface composition. In several instances, the samples were also cut to determine the depth profile of the coating. Several of the early runs did not yield uniform or deep enough coatings and hence a significant portion of the effort in this period was devoted fixing the problems with our fluidized bed reactor. Before the end of the quarter we had prepared a number of samples, many of them in duplicates, and sent one set to Wabash River Energy Laboratory for them to install in their gasifier. The gasifier was undergoing a scheduled maintenance and thus presented an opportunity to place some of our coupons in the stream of an operating gasifier. The samples submitted included coated and uncoated pairs of different alloys.

  14. Non-contact evaluation of mechanical properties of electroplated wear resistant Ni-P layer from the velocity dispersion of laser SAW; Laser reiki Rayleigh ha no sokudo bunsan wo mochiita taimamo Ni-P mekkiso tokusei no hisesshoku hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Morikawa, Y.; Cho, H.; Takemoto, M. [Aoyama Gakuin University, Tokyo (Japan). Faculty of Science and Engineering; Nakayama, T. [Kobe Steel Ltd., Kobe (Japan)

    1996-11-01

    We developed a new laser surface acoustic wave (SAW) system and applied this to estimate the mechanical properties of the wear-resistant Ni-P layer electroplated on a stainless steel. The velocity dispersions of Rayleigh wave of the as -plated and heat-treated Ni-P layer were obtained by the one point time domain signal processing. The Ni-P layers with excellent wear resistance produced by the heated treatment higher than 725K were found to show higher Rayleigh velocities than that of the substrate steel, while the Ni-P layer with poor wear resistance showed lower velocities. Young`s moduli of the Ni-P layer, estimated so as the computed velocity dispersion agreed with the measured one, increased with the increase of wear resistance. 10 refs., 9 figs., 2 tabs.

  15. Microstructure Characterization and Wear-Resistant Properties Evaluation of an Intermetallic Composite in Ni–Mo–Si System

    National Research Council Canada - National Science Library

    Huang, Boyuan; Song, Chunyan; Liu, Yang; Gui, Yongliang

    2017-01-01

    ... compounds have been studied for their potential application as structural wear materials or coatings on engineering steels. In the present work, a newly designed intermetallic composite in a Ni–M...

  16. Qualitative Assessment of Wear Resistance and Surface Hardness of Different Commercially Available Dental Porcelain: An in vitro Study.

    Science.gov (United States)

    Singh, Abhishek; Nagpal, Abhishek; Pawah, Salil; Pathak, Chetan; Issar, Gaurav; Sharma, Pankaj

    2016-09-01

    In an attempt to minimize wear damage to the enamel of antagonist teeth, new low and medium fusing ceramic materials have been developed. Manufacturers usually claim that these ceramics are wear-friendly because of their lower hardness, lower concentrations of crystal phase, and smaller crystal sizes. This study aimed to quantitatively analyze the wear strength of various commercially available dental porcelain with tooth enamel as well as the surface hardness of these dental porcelain. The basic model was designed as a pin on plate arrangement. The tooth specimens were mounted on the stylus which was centered on the ceramic specimen in a wear testing machine. The dental ceramic specimen was centered in the metal die. A load of 40 N was applied at a rate of 80 cycles/minute for 15 minutes. In the current study, mean wear depth (Ra) value, volumetric loss, and surface hardness were obtained by standard quantification method and were statistically evaluated. Ceramco-3 was reported to be most abrasive for enamel; however, Duceram love significantly more abraded itself than the other two, Ceramco-3 and Vita Alpha, and generated the lowest loss of enamel. Also, same abrasive type of wear was revealed for all three variants of tested ceramics. Ceramco-3 was the most abrasive for enamel, while surface roughness (mean wear depth) of Duceram love was maximum and for Ceramco-3 it was minimum. The value of surface roughness for Vita Alpha was in between Duceram love and Ceramco-3. Nonetheless, the mean surface hardness of Duceram love was found to be least and maximum for Vita Alpha. In situations of dental wear and wasting tooth disease (Attrition/Abrasion), Duceram can be applied in lieu of Ceramco-3 so as to prevent worsening of existing dentition. However, in younger patients Vita Alpha would offer maximum durability due to its greater surface hardness.

  17. Microstructure and wear resistance of Al2O3-M7C3/Fe composite coatings produced by laser controlled reactive synthesis

    Science.gov (United States)

    Tan, Hui; Luo, Zhen; Li, Yang; Yan, Fuyu; Duan, Rui

    2015-05-01

    Based on the principle of thermite reaction of Al and Fe2O3 powders, the Al2O3 ceramic reinforced Fe-based composite coatings were fabricated on a steel substrate by laser controlled reactive synthesis and cladding. The effects of different additions of thermite reactants on the phase transition, microstructure evolution, microhardness and wear resistance of the composite coatings were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Vickers microhardness and block-on-ring wear test, respectively. The results show that Al2O3 ceramic and M7C3 carbide are in situ synthesized via the laser controlled reactive synthesis. The Al2O3 ceramic and M7C3 carbides prefer to distribute along the γ-Fe phase boundary continuously, which separates the γ-Fe matrix and is beneficial to the grain refinement. With the increase of thermite reactants, the amount of Al2O3 ceramic and M7C3 carbide in the composite coatings increases gradually. Moreover the cladding layer changes from dendritic structure to columnar structure and martensite structure in the heat affected zone becomes coarse. The increased thermite reactants improve the microhardness and wear resistance of the in situ composite coatings obviously and enhance the hardness of the heat affected zone, which should be ascribed to the grain refinement, ceramic and carbide precipitation and solid solution strengthening.

  18. Microstructure and Wear Resistance of Laser-Clad (Co, Ni61.2B26.2Si7.8Ta4.8 Coatings

    Directory of Open Access Journals (Sweden)

    Luan Zhang

    2017-10-01

    Full Text Available It has been reported that a quaternary Co61.2B26.2Si7.8Ta4.8 alloy is a good glass former and can be laser-clad to an amorphous composite coating with superior hardness and wear resistance. In this paper, alloys with varying Ni contents to substitute for Co are coated on the surface of #45 carbon steel using a 5-kW CO2 laser source for the purpose of obtaining protective coatings. In contrast to the quaternary case, the clad layers are characterized by a matrix of α-(Fe, Co, Ni solid solution plus CoB, Co3B, and Co3Ta types of precipitates. The cladding layer is divided into four regions: Near-surface dendrites, α-(Fe, Co, Ni solid solution plus dispersed particles in the middle zone, columnar bonding zone, and heat-affected area that consists of martensite. The hardness gradually decreases with increasing Ni content, and the maximum hardness occurs in the middle zone. Both the friction coefficient and wear volume are minimized in the alloy containing 12.2% Ni. Compared with the previous cobalt-based quaternary alloy Co61.2B26.2Si7.8Ta4.8, the addition of the Ni element reduces the glass-forming ability and henceforth the hardness and wear resistance of the clad layers.

  19. Effects of Duplex Nitriding and TiN Coating Treatment on Wear Resistance, Corrosion Resistance and Biocompatibility of Ti6Al4V Alloy

    Science.gov (United States)

    Kao, W. H.; Su, Y. L.; Hsieh, Y. T.

    2017-08-01

    Ti6Al4V alloy substrates were nitrided at 900 °C. TiN coatings were then deposited on the nitrided substrates using a closed-field unbalanced magnetron sputtering system. The microstructure, hardness and adhesion properties of the TiN-N-Ti6Al4V substrates were evaluated and compared with those of an untreated Ti6Al4V sample, a nitrided Ti6Al4V sample and a TiN-coated Ti6Al4V sample, respectively. The tribological properties of the various samples were investigated by means of reciprocating sliding wear tests performed in 0.9 wt.% NaCl solution against 316L, Si3N4 and Ti6Al4V balls, respectively. In addition, the corrosion resistance was evaluated using potentiodynamic polarization tests. Finally, the biocompatibility of the samples was investigated by observing the attachment and growth of purified mouse leukemic monocyte/macrophage cells (Raw 264.7) on the sample surface after culturing periods of 24, 72 and 120 h, respectively. Overall, the results showed that the duplex nitriding/TiN coating treatment significantly improved the tribological, anti-corrosion and biocompatibility properties of the original Ti6Al4V alloy.

  20. Wear resistant pavement study.

    Science.gov (United States)

    2009-01-01

    This report documents the construction of three special pavement test sections on I-90 east of Spokane, Washington. The test sections included ultra-thin and thin whitetopping, Modified Class D open graded asphalt concrete, and micro/macro surfacing ...

  1. Wear, delamination, and fatigue resistance of melt-annealed highly crosslinked UHMWPE cruciate-retaining knee inserts under activities of daily living.

    Science.gov (United States)

    Popoola, Oludele O; Yao, Jian Q; Johnson, Todd S; Blanchard, Cheryl R

    2010-09-01

    The wear, delamination, and fatigue resistance of artificially aged gamma irradiation-sterilized conventional polyethylene (CPE) and gas-plasma-sterilized melt-annealed highly crosslinked polyethylene tibial inserts (HXPE) were compared. Six CPE and 12 HXPE (six irradiated at 58 kGy and six at 72 kGy) left knee inserts were wear tested for 5.5 million cycles (Mc) under loads and motions that mimic activities of daily living, such as walking, chair rise, stair ascent, and deep squatting. Another six HXPE (72 kGy) and six CPE inserts were also tested under conditions that could produce severe delamination for 8 Mc. Ten other knees (five 72 kGy HXPE and five CPE) were subjected to posterior edge loading fatigue testing for 5 Mc. The HXPE inserts had an average wear rate reduction of about 80% relative to their CPE counterparts during all activities. All of the CPE inserts delaminated and fractured during high cycle deep squat (152 degrees flexion) motions, while all the HXPE remained intact. None of the HXPE inserts delaminated after 8 Mc, while all of the CPE inserts developed delamination damage within 1.5-5.8 Mc of delamination testing. All CPE inserts developed subsurface cracks and delamination within 2.8 Mc during posterior edge loading fatigue studies, while none of the HXPE inserts showed cracking or delamination after 5 Mc. These results show that aged HXPE has higher wear and fatigue resistance than aged CPE, and offers potential long-term advantages for young active patients with sustained activities of daily living. (c) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  2. Remarkable improvement of the wear resistance of poly(vinylidene difluoride) by incorporating polyimide powder and carbon nanofibers

    Science.gov (United States)

    Min, Chunying; Liu, Dengdeng; Shen, Chen; Zhang, Qiaqia; Shen, Xiaojuan; Zhang, Kan

    2017-10-01

    Poly(vinylidene difluoride) (PVDF) composites reinforced via adding different fillers have attracted wide attention in the field of dielectric materials, but few have been reported in the tribological area. In this paper, the effect of polyimide (PI) powder and carbon nanofibers (CF) as reinforcement phases on the friction and wear performance of PVDF composites has been investigated. It was found that PI powder enhances the mechanical and tribological properties of PVDF and especially as the content of the PI powder reaches 5 wt%. In addition, CF and PI exhibited synergistic effect on the tribological properties of PVDF. With PVDF containing 5 wt% PI powder and 20 wt% CF, the friction and wear behavior of the PVDF composite showed the best performance. PVDF, PI powder and CF can form a consistent network structure, which prevents the polymer molecular chains from moving or deformation, decreasing the wear loss of PVDF composites.

  3. Eye Wear

    Science.gov (United States)

    Eye wear protects or corrects your vision. Examples are Sunglasses Safety goggles Glasses (also called eyeglasses) Contact ... jobs and some sports carry a risk of eye injury. Thousands of children and adults get eye ...

  4. An Investigation on the Wear Resistance and Fatigue Behaviour of Ti-6Al-4V Notched Members Coated with Hydroxyapatite Coatings

    Directory of Open Access Journals (Sweden)

    Reza H Oskouei

    2016-02-01

    Full Text Available In this study, surface properties of Ti-6Al-4V alloy coated with hydroxyapatite coatings were investigated. Wear resistance and fatigue behaviour of samples with coating thicknesses of 10 and 50 µm as well as uncoated samples were examined. Wear experiments demonstrated that the friction factor of the uncoated titanium decreased from 0.31 to 0.06, through a fluctuating trend, after 50 cycles of wear tests. However, the friction factor of both the coated samples (10 and 50 µm gradually decreased from 0.20 to 0.12 after 50 cycles. At the end of the 50th cycle, the penetration depth of the 10 and 50 µm coated samples were 7.69 and 6.06 µm, respectively. Fatigue tests showed that hydroxyapatite coatings could improve fatigue life of a notched Ti-6Al-4V member in both low and high cycle fatigue zones. It was understood, from fractography of the fracture surfaces, that the fatigue zone of the uncoated specimens was generally smaller in comparison with that of the coated specimens. No significant difference was observed between the fatigue life of coated specimens with 10 and 50 µm thicknesses.

  5. Hardness and wear resistance of steel-based surface composites fabricated with Fe-based metamorphic alloy powders by high-energy electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyuhong [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Nam, Duk-Hyun [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Lee, Sunghak [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)]. E-mail: shlee@postech.ac.kr; Kim, Choongnyun Paul [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

    2006-07-25

    In this study, steel-based surface composites were fabricated with Fe-based metamorphic alloy powders by high-energy electron beam irradiation, and their microstructure, hardness, and wear resistance were investigated. Two kinds of Fe-based metamorphic powders were deposited on a plain carbon steel substrate, and then electron beam was irradiated on these powders to fabricate one-layered surface composites. Two-layered surface composites were also fabricated by irradiating electron beam again onto the powders deposited on the one-layered surface composites. The composite layers of 2.6-3.1 mm in thickness were homogeneously formed without defects, and contained a large amount (up to 64 vol.%) of Cr{sub 2}B or Cr{sub 1.65}Fe{sub 0.35}B{sub 0.96} borides in the Cr{sub 0.19}Fe{sub 0.7}Ni{sub 0.11} or martensite matrix. Since the hardness and wear resistance of the surface composite layers were directly influenced by hard borides, they were two to four times greater than those of the steel substrate. These borides also played a role in improving the high-temperature hardness because they are insoluble and thermally stable even at high temperatures. These findings suggested that various applications of the fabricated surface composites to materials requiring high resistance to heat and abrasion were expected.

  6. The structure influence of resistance wear-out covering, which have get with help of detonation - gas vaporization

    Directory of Open Access Journals (Sweden)

    В.Д. Гулевець

    2004-03-01

    Full Text Available  It is presented an experimental studies of the structure surfaces changing at air loading, learned mechanism of formation and composition of the secondary structures, is the reason of wear-out stability of composite covering on nickel and chromium base.

  7. Resistance Welding of Advanced Materials and Micro Components

    DEFF Research Database (Denmark)

    Friis, Kasper Storgaard

    With the use of the Finite Element Method it has become possible to analyse and better understand complex physical processes such as the resistance welding by numerical simulation. However, simulation of resistance welding is a very complex matter due to the strong interaction between mechanical...... aimed at improving the understanding of resistance welding for increasing the accuracy of numerical simulation of the process. Firstly methods for measuring and modelling mechanical and electrical properties at a wide range of temperatures is investigated, and especially the electrical contact...... resistance is addressed both theoretically and experimentally. Secondly the consequences of downscaling the process is investigated experimentally and discussed in relation to simulation of the process. Finally resistance welding of advanced high strength steels is addressed aimed at improving the simulation...

  8. Effects of hard chrome and MoN-coated stainless steel on wear behaviour and tool life model under two-body abrasion wear testing

    Directory of Open Access Journals (Sweden)

    P. Srisattayakul

    2017-01-01

    Full Text Available The objectives of this study were to investigate the effect of the electroplated hard chrome (HC and the MoNcoated AISI 316 stainless steel coatings on weight loss under two-body abrasion wear testing and to predict the tool life of both materials used as a fishing net-weaving machine component, namely the hook. Both materials were used to carry out the wear experiments under two-body abrasion behavior. These specimens were wear tested with the in-house wear testing apparatus base on ASTM: G133-05 standard. The Taylor’s equation was used to formulate the tool life model whereas the Monte Carlo simulation was used to predict the tool life of the machine part. The results showed that the MoN-HC exhibited higher wear resistance than that of the HC.

  9. ANALYSIS OF INSULIN RESISTANCE IN VARIOUS COMPONENTS OF METABOLIC SYNDROME

    OpenAIRE

    Pankaj Maheria; Deepak Parchwani; Amit Upadhyay; Manoj Kumar Sharma

    2011-01-01

    Metabolic syndrome is a collection of health risks that increases chances of developing heart disease. The constellation of metabolic abnormalities includes glucose intolerance, central obesity, dyslipidemia, and hypertension. These conditions can occur in an individual more often than might be expected by chance. The aim of this study was to analyze the insulin resistance measured as Homeostasis model assessment of insulin resistance (HOMA-IR) in different variables of metabolic syndrome. In...

  10. Dietary Components in the Development of Leptin Resistance123

    Science.gov (United States)

    Vasselli, Joseph R.; Scarpace, Philip J.; Harris, Ruth B. S.; Banks, William A.

    2013-01-01

    Classically, leptin resistance has been associated with increased body fat and circulating leptin levels, and the condition is believed to contribute to the onset and/or maintenance of obesity. Although a great deal is known about the central nervous system mechanisms mediating leptin resistance, considerably less is known about the role of diet in establishing and maintaining this altered hormonal state. An exciting new finding has recently been published demonstrating the existence of leptin resistance in normal-weight rats with lean leptin levels by feeding them a high-concentration-fructose diet. This finding has opened the possibility that specific macronutrients may be capable of inducing leptin resistance, independently of the amount of body fat or circulating leptin present in the treated animals. This review describes several lines of research that have recently emerged indicating that specific types of dietary sugars and fats are capable of inducing leptin resistance in experimental rodent models. The results further show that diet-induced leptin resistance is capable of increasing energy intake and elevating body weight gain under appropriate dietary challenges. It appears that biological mechanisms on multiple levels may underlie the dietary induction of leptin resistance, including alterations in the leptin blood-to-brain transport system, in peripheral glucose metabolism, and in central leptin receptor signaling pathways. What is clear from the findings reviewed here is that diet-induced leptin resistance can occur in the absence of elevated circulating leptin levels and body weight, rendering it a potential cause and/or predisposing factor to excess body weight gain and obesity. PMID:23493533

  11. Effects of sex steroids on components of the insulin resistance syndrome in transsexual subjects

    NARCIS (Netherlands)

    Elbers, Jolanda M H; Giltay, Erik J; Teerlink, Tom; Scheffer, Peter G; Asscheman, Henk; Seidell, Jacob C; Gooren, Louis J G

    2003-01-01

    OBJECTIVE: Sex differences are found in most components of the insulin resistance syndrome and the associated cardiovascular risk profile. These differences are attributed to sex-specific sex steroid profiles, but the effects of sex steroids on the individual components of the insulin resistance

  12. Effects of sex steroids on components of the insulin resistance syndrome in transsexual subjects

    NARCIS (Netherlands)

    Elbers, J.M.H.; Giltay, E.J.; Teerlink, T.; Scheffer, P.G.; Asscheman, H.; Seidell, J.C.; Gooren, L.J.G.

    2003-01-01

    objective Sex differences are found in most components of the insulin resistance syndrome and the associated cardiovascular risk profile. These differences are attributed to sex-specific sex steroid profiles, but the effects of sex steroids on the individual components of the insulin resistance

  13. Effect of short LED lamp exposure on wear resistance, residual monomer and degree of conversion for Filtek Z250 and Tetric EvoCeram composites.

    Science.gov (United States)

    Kopperud, Hilde M; Johnsen, Gaute F; Lamolle, Sébastien; Kleven, Inger S; Wellendorf, Hanne; Haugen, Håvard J

    2013-08-01

    The latest LED dental curing devices claim sufficient curing of restorative materials with short curing times. This study evaluates mechanical and chemical properties as a function of curing time of two commercial composite filling materials cured with three different LED lamps. The composites were Filtek Z250 (3M ESPE) and Tetric EvoCeram (Ivoclar Vivadent) and the LED curing devices were bluephase 16i (Ivoclar Vivadent), L.E.Demetron II (Kerr) and Mini L.E.D. (Satelec). Control samples were cured with a QTH-lamp (VCL 400, Kerr). The wear resistance after simulated tooth brushing, degree of conversion, curing depth, and amounts of residual monomers were measured after different curing times. The results of this study show that short curing time with high-intensity LEDs may influence the bulk properties of the materials, resulting in lower curing depth and increased residual monomer content. The measured surface properties of the materials, degree of conversion and wear resistance, were not affected by short curing times to the same extent. This study demonstrates that reduced exposure time with high intensity LEDs can result in composite restorations with inferior curing depth and increased leaching of monomers. Dentists are recommended to use sufficient curing times even with high intensity LEDs to ensure adequate curing and minimize the risk of monomer leaching. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  14. Friction Induced Wear of Rapid Prototyping Generated Materials: A Review

    Directory of Open Access Journals (Sweden)

    A. Tsouknidas

    2011-01-01

    Full Text Available Additive manufacturing has been introduced in the early 80s and has gained importance as a manufacturing process ever since. Even though the inception of the implicated processes predominantly focused on prototyping purposes, during the last years rapid prototyping (RP has emerged as a key enabling technology for the fabrication of highly customized, functionally gradient materials. This paper reviews friction-related wear phenomena and the corresponding deterioration mechanisms of RP-generated components as well as the potential of improving the implicated materials' wear resistance without significantly altering the process itself. The paper briefly introduces the concept of RP technologies and the implicated materials, as a premises to the process-dependent wear progression of the generated components for various degeneration scenarios (dry sliding, fretting, etc..

  15. Microstructure, Residual Stress, Corrosion and Wear Resistance of Vacuum Annealed TiCN/TiN/Ti Films Deposited on AZ31

    Directory of Open Access Journals (Sweden)

    Haitao Li

    2016-12-01

    Full Text Available Composite titanium carbonitride (TiCN thin films deposited on AZ31 by DC/RF magnetron sputtering were vacuum annealed at different temperatures. Vacuum annealing yields the following on the structure and properties of the films: the grain grows and the roughness increases with an increase of annealing temperature, the structure changes from polycrystalline to single crystal, and the distribution of each element becomes more uniform. The residual stress effectively decreases compared to the as-deposited film, and their corrosion resistance is much improved owing to the change of structure and fusion of surface defects, whereas the wear-resistance is degraded due to the grain growth and the increase of surface roughness under a certain temperature.

  16. Laser Surface Modification of Ti6Al4V-Cu for Improved Microhardness and Wear Resistance Properties

    OpenAIRE

    Erinosho, Mutiu Folorunsho; Akinlabi, Esther Titilayo; Pityana, Sisa; Owolabi, Gbadebo

    2017-01-01

    To modify the properties of Ti6Al4V alloy, Cu has been added to host an antimicrobial effect in the revised alloy for marine application. The Laser Metal Deposition (LMD) process on the Ti6Al4V alloy and Cu was been investigated for surface modification in order to combat the problem of biofouling in the marine industry. The investigations focused on the microstructural observations, micro-hardness measurements and dry sliding wear in the presence of 3 and 5 weight percents of Cu. The microst...

  17. Wear performance of laser processed tantalum coatings

    Energy Technology Data Exchange (ETDEWEB)

    Dittrick, Stanley; Balla, Vamsi Krishna; Bose, Susmita; Bandyopadhyay, Amit, E-mail: amitband@wsu.edu

    2011-12-01

    This first generation investigation evaluates the in vitro tribological performance of laser-processed Ta coatings on Ti for load-bearing implant applications. Linear reciprocating wear tests in simulated body fluid showed one order of magnitude less wear rate, of the order of 10{sup -4} mm{sup 3}(N.m){sup -1}, for Ta coatings compared to Ti. Our results demonstrate that Ta coatings can potentially minimize the early-stage bone-implant interface micro-motion induced wear debris generation due to their excellent bioactivity comparable to that of hydroxyapatite (HA), high wear resistance and toughness compared to popular HA coatings. Highlights: {yields} In vitro wear performance of laser processed Ta coatings on Ti was evaluated. {yields} Wear tests in SBF showed one order of magnitude less wear for Ta coatings than Ti. {yields} Ta coatings can minimize early-stage micro-motion induced wear debris generation.

  18. Detection of Corrosion Resistance of Components in Cyclic Salt Spray

    Directory of Open Access Journals (Sweden)

    Štefan Álló

    2015-01-01

    Full Text Available The aim of this research is, to investigate the influence of two types of cyclic salt spray tests on parts surface treated with galvanizing. On the selected components was performed the method Zn-Ni surface treating on the bath line. Subsequently were the components embedded in the corrosion chamber, where was performed two types of cyclic salt test. In the first test was performed 4 hour salt spray, 8 hours drying, 60 hours condensation and 24 hours drying. Once cycle lasted 96 hours, and it was repeated 4 times. During the second test was performed 2 hours salt spray, 2 hours condensation. The cycle was repeated 4 times, that means 96 hours. After the cycle was performed 72 hours free relaxation in the corrosion chamber, on 20–25 °C temperature. As the research showed, after the cyclic salt spray was no red corrosion on the selected components. The white corrosion appeared only slightly.

  19. Tooth wear

    Directory of Open Access Journals (Sweden)

    Tušek Ivan

    2014-01-01

    Full Text Available Tooth wear is the loss of dental hard tissue that was not caused by decay and represents a common clinical problem of modern man. In the etiology of dental hard tissue lesions there are three dominant mechanisms that may act synergistically or separately:friction (friction, which is caused by abrasion of exogenous, or attrition of endogenous origin, chemical dissolution of dental hard tissues caused by erosion, occlusal stress created by compression and flexion and tension that leads to tooth abfraction and microfracture. Wear of tooth surfaces due to the presence of microscopic imperfections of tooth surfaces is clinically manifested as sanding veneers. Tribology, as an interdisciplinary study of the mechanisms of friction, wear and lubrication at the ultrastructural level, has defined a universal model according to which the etiopathogenesis of tooth wear is caused by the following factors: health and diseases of the digestive tract, oral hygiene, eating habits, poor oral habits, bruxism, temporomandibular disorders and iatrogenic factors. Attrition and dental erosion are much more common in children with special needs (Down syndrome. Erosion of teeth usually results from diseases of the digestive tract that lead to gastroesophageal reflux (GER of gastric juice (HCl. There are two basic approaches to the assessment of the degree of wear and dental erosion. Depending on the type of wear (erosion, attrition, abfraction, the amount of calcium that was realised during the erosive attack could be determined qualitatively and quantitatively, or changes in optical properties and hardness of enamel could be recorded, too. Abrasion of teeth (abrasio dentium is the loss of dental hard tissue caused by friction between the teeth and exogenous foreign substance. It is most commonly provoked by prosthetic dentures and bad habits, while its effect depends on the size of abrasive particles and their amount, abrasive particle hardness and hardness of tooth

  20. Facile preparation of superamphiphobic epoxy resin/modified poly(vinylidene fluoride)/fluorinated ethylene propylene composite coating with corrosion/wear-resistance

    Science.gov (United States)

    Wang, Huaiyuan; Liu, Zhanjian; Wang, Enqun; Zhang, Xiguang; Yuan, Ruixia; Wu, Shiqi; Zhu, Yanji

    2015-12-01

    A robust superamphiphobic epoxy resin (EP)/modified poly(vinylidene fluoride) (MPVDF)/fluorinated ethylene propylene (FEP) composite coating has been prepared through the combination of chemical modification and spraying technique. Nanometer silica (SiO2, 2.5 wt.%) and carbon nanotubes (CNTs, 2.5 wt.%) were added in the coating to construct the necessary reticulate papillae structures for superamphiphobic surface. The prepared EP composite coating demonstrated high static contact angles (166°, 155°) and low sliding angles (3°, 5°) to water and glycerol, respectively. Moreover, the prepared coating can also retain superhydrophobicity under strongly acidic and alkaline conditions. The brittleness of EP can be avoided by introducing the malleable MPVDF. The wear life of the EP composite coating with 25 wt.% FEP was improved to 18 times of the pure EP coating. The increased wear life of the coating can be attributed to the designed nano/micro structures, the self-lubrication of FEP and the chemical reaction between EP and MPVDF. The anti-corrosion performance of the coatings was investigated in 3.5% NaCl solution using potentiodynamic polarization. The results showed that the prepared superamphiphobic composite coating was most effective in corrosion resistance, primarily due to the barrier effect for the diffusion of O2 and H2O molecules. It is believed that this robust superamphiphobic EP/MPVDF/FEP composite coating prepared by the facile spray method can pave a way for the large-scale application in pipeline transport.

  1. Improvement in wear and corrosion resistance of AISI 1020 steel by high velocity oxy-fuel spray coating containing Ni-Cr-B-Si-Fe-C

    Science.gov (United States)

    Prince, M.; Thanu, A. Justin; Gopalakrishnan, P.

    2012-04-01

    In this investigation, AISI 1020 low carbon steel has been selected as the base material. The Ni based super alloy powder NiCrBSiFeC was sprayed on the base material using high velocity oxy-fuel spraying (HVOF) technique. The thickness of the coating was approximately 0.5 mm (500 μm). The coating was characterized using optical microscopy, Vickers microhardness testing, X-ray diffraction technique and scanning electron microscopy. Dry sliding wear tests were carried out at 3 m/s sliding speed under the load of 10 N for 1000 m sliding distance at various temperatures i.e., 35° C, 250° C and 350° C. The corrosion test was carried out in 1 M copper chloride in acetic acid solution. The polarization studies were also conducted for both base material and coating. The improvement in microhardness from 1.72 GPa (175 HV0.05) to 10.54 GPa (1075 HV0.05) was observed. The coatings exhibited 3-6 times improved wear resistance as compared with base material. Also, the corrosion rate was reduced by 3.5 times due to the presence of coatings.

  2. Plasma Components as Traits for Resistance to Coccidiosis in Chicken

    DEFF Research Database (Denmark)

    Hamzic, Edin; Bed'Hom, Bertrand; Juin, Hervé

    2014-01-01

    For successful genetic dissection of disease resistance it is of great importance to accurately identify the respective phenotypes. In case of coccidiosis some of the conventional phenotypes don’t fully reflect the animal health status. The objective of this study was large-scale evaluation...... were performed on subset of 184 extreme animals selected based on body weight gain. All fractions of plasma proteins associated with acute phase proteins, except β1-globulin, have been significantly elevated. We observed that the best estimation of plasma coloration variation under a coccidiosis...

  3. Relationship Between Simulated Gap Wear and Generalized Wear of Resin Luting Cements.

    Science.gov (United States)

    Tsujimoto, A; Barkmeier, W W; Takamizawa, T; Latta, M A; Miayazaki, M

    The relationship between the simulated gap wear and generalized wear of resin luting cements was investigated. Five resin luting cements, G-Cem LinkForce (GL), Multilink Automix (MA), NX3 Nexus, Panavia V5 (PV), and RelyX Ultimate were evaluated and subsequently subjected to a wear challenge in a Leinfelder-Suzuki (Alabama) wear simulation device. Half of the specimens from each resin luting cement were photo-cured for 40 seconds and the other half were not photo-cured. The simulated gap and generalized wear were generated using a flat-ended stainless steel antagonist. Wear testing was performed in a water slurry of polymethyl methacrylate beads, and the simulated gap and generalized wear were determined using a noncontact profilometer (Proscan 2100) in conjunction with the Proscan and AnSur 3D software. A strong relationship was found between the gap wear and generalized wear simulation models. The simulated gap wear and generalized wear of the resin luting cements followed similar trends in terms of both volume loss and mean depth of wear facets with each curing method. Unlike the simulated gap wear and generalized wear of GL and PV, those of MA, NX, and RU were influenced by the curing method. The results of this study indicate that simulated gap wear of resin luting cements is very similar to simulated generalized wear. In most cases, dual curing appears to ensure greater wear resistance of resin luting cements than chemical curing alone. The wear resistance of some resin luting cements appears to be material dependent and is not influenced by the curing method.

  4. "Bio-glues" to enhance slipperiness of mucins: improved lubricity and wear resistance of porcine gastric mucin (PGM) layers assisted by mucoadhesion with chitosan.

    Science.gov (United States)

    Nikogeorgos, Nikolaos; Efler, Petr; Kayitmazer, A Basak; Lee, Seunghwan

    2015-01-21

    A synergetic lubricating effect between porcine gastric mucin (PGM) and chitosan based on their mucoadhesive interaction is reported at a hydrophobic interface comprised of self-mated polydimethylsiloxane (PDMS) surfaces. In acidic solution (pH 3.2) and low concentrations (0.1 mg mL(-1)), the interaction of PGM with chitosan led to surface recharge and size shrinkage of their aggregates. This resulted in higher mass adsorption on the PDMS surface with an increasing weight ratio of [chitosan]/[PGM + chitosan] up to 0.50. While neither PGM nor chitosan exhibited slippery characteristics, the coefficient of friction being close to 1, their mixture improved considerably the lubricating efficiency (the coefficient of friction is 0.011 at an optimum mixing ratio) and wear resistance of the adsorbed layers. These findings are explained by the role of chitosan as a physical crosslinker within the adsorbed PGM layers, resulting in higher cohesion and lower interlayer chain interpenetration and bridging.

  5. The Influence Of Temperature Gradient On Stereological Parameters Of Carbide Phase On Cross-Section Of Abrasive Wear Resistant Chromium Cast Iron

    Directory of Open Access Journals (Sweden)

    Studnicki A.

    2015-09-01

    Full Text Available In the paper analysis of temperature gradient and parameters of structure on casting cross-section of abrasive wear resistant chromium cast iron at carbon content of 2,5%wt. and chromium 17%wt. with nickel and molybdenum additives are presented. The castings were made with use of special tester ϕ100mm (method of temperature gradient and derivative analysis with temperature recording in many points from thermal centre to surface (to mould of casting. Registered cooling curves were used to describe the temperature gradient on cross-section of analyzed casting. On the basis of determined curves of temperature gradient measurement fields were selected to make the quantitative studies of structure. The results of studies show significant influence of temperature gradient on quantitative parameters of chromium cast iron structure. Moreover was affirmed that exists a critical temperature gradient for which is present rapid change of quantitative parameters of chromium cast iron structure.

  6. Combined effect of rapid nitriding and plastic deformation on the surface strength, toughness and wear resistance of steel 38CrMoAlA

    DEFF Research Database (Denmark)

    Wang, B.; Lv, Z.A.; Zhou, Z.A.

    2015-01-01

    The combined treatment of pressurized gas nitriding and cold rolling is proposed as a new approach to rapid preparation of a strong and tough nitrided layer for steel 38CrMoAlA. The microstructural characteristics and properties of the modified surface layer in comparison with those of the conven......The combined treatment of pressurized gas nitriding and cold rolling is proposed as a new approach to rapid preparation of a strong and tough nitrided layer for steel 38CrMoAlA. The microstructural characteristics and properties of the modified surface layer in comparison with those...... of the conventionally gas nitrided sample have systematically been evaluated. The results show that the hardness and toughness of the nitrided surface layer can be significantly improved by the combined treatment. Especially, the wear resistance of nitrided surface layer under heavy loads was greatly enhanced. It can...

  7. Karakterizacija WCCo/NiCrBSi prevlake otporne na habanje / Characterization of wear resistant plasma sprayed WCCo/NiCrBSi self-fluxing coatings

    Directory of Open Access Journals (Sweden)

    Mihailo R. Mrdak

    2010-04-01

    Full Text Available U radu su analizirani mikrostruktura, mehaničke i tribološke karakteristike (APS prevlake WCCoNiCrBSi koja se primenjuje za reparaciju cilindara nosne noge helikoptera. Tribološka procena prevlake određena je primenom tribometra blok-na-prstenu. Spregnuti materijalblokovi sa prevlakom ispitani su na okaljenom i poboljšanom čeličnom prstenu. Za ukupno odstojanje od 3000 m bili su konstantna brzina 0,5 m/s i opterećenje 400 N. Prednost primene ove prevlake je u značajnom produženju resursa delova uz smanjenje troškova eksploatacije i održavanja. / In this paper, the microstructural, mechanical and tribological properties of WCCoNiCrBSi thermal spray coatings, applied to repair the cylinders of helicopter nasal feet, were analyzed. The process used for coating deposition on steel substrate was the Atmospheric Plasma Spraying (APS.The plasma spray process is a procedure widely used for applying coatings with increased resistance to wear. The combination of WCCo and NiCrBSi powders produced coatings for the protection of metal parts exposed to wear abrasion, erosion and cavitation to 540°C. The WCCoNiCrBSi 50/50% powder is specially developed for the production of coatings of high cohesion and adhesive strength. The coatings are very dense, hard and smooth. Microstructures present in the layers are tungsten carbides and chromium layers that increase resistance to wear and abrasion. Powder is deposited on the substrate rugged with Al2O3. The substrates were heated at temperatures up to 200°C. Powder deposition was performed with the optimal deposition parameters The microstructure and micro hardness of the coating layer was investigated on the cross section of samples using the Pratt & Whitney standard. Micro hardness was tested using the Vickers scale with a load of 300g. The microstructure of the layers was investigated on an optical microscope (OM with a magnification of 400X. Testing of bond strength between coatings and substrates

  8. Explore the electron work function as a promising indicative parameter for supplementary clues towards tailoring of wear-resistant materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian [School of Mechanical Engineering, Taiyuan University of Science and Technology (China); Department of Chemical and Materials Engineering, University of Alberta (Canada); Lu, Hao; Bin Yu [Department of Chemical and Materials Engineering, University of Alberta (Canada); Wang, Rongfeng [School of Mechanical Engineering, Taiyuan University of Science and Technology (China); Hua, Guomin [Department of Chemical and Materials Engineering, University of Alberta (Canada); Yan, Xianguo [School of Mechanical Engineering, Taiyuan University of Science and Technology (China); Parent, Leo [Suncor Energy, Fort McMurray, Alberta, Canada T9H 3E3 (Canada); Tian, Harry [Metallurgical/Materials R& D, GIW Industries, Grovetown, GA 30813-2842 (United States); Chung, Reinaldo [Suncor Energy, Fort McMurray, Alberta, Canada T9H 3E3 (Canada); Li, Dongyang, E-mail: dongyang.li@ualberta.ca [School of Mechanical Engineering, Taiyuan University of Science and Technology (China); Department of Chemical and Materials Engineering, University of Alberta (Canada)

    2016-07-04

    For materials used under dynamic loading conditions such as impact and impact wear, an appropriate balance between hardness and toughness is highly desired. However, determination of such a balance is challenging, since the toughness depends on both the mechanical strength and ductility, which complicates the judgement and control. Besides, local defects, poor phases and interfaces all could trigger local cracking and consequent global failure. These undesired structural or microstructural imperfections increase the difficulty in controlling the hardness-toughness balance. In this article, using high-Cr cast irons (HCCI) as example, we demonstrate that electron work function is a promising indicative parameter for supplementary clues to adjust the balance between hardness and toughness for HCCIs towards improved performance.

  9. Experimental investigation on wear resistance of a new cutting fluid using a four ball tribometer – optimization of additive percent

    Directory of Open Access Journals (Sweden)

    Paleu Viorel

    2017-01-01

    Full Text Available The cutting fluid manufacturers aim to obtain the best products at the lowest possible price. To achieve such a compromise experimental work is needed, trying to get the lowest allowed content of additive in the base oil. The paper presents the results of standard tests carried out on four ball machine. This tribometer is used to analyze the load-carrying properties of cutting fluids. The results are compared with the standard requirements, related to the measured wear scar on the three lower balls of the four ball device. An optimum of sulphur additive content into the base oil was found around 10%. According to the actual standards and following the results of carried-out tests, for this specific case the lowest acceptable content of additive is around 4%.

  10. Delamination and adhesive wear behavior of alpha-tocopherol-stabilized irradiated ultrahigh-molecular-weight polyethylene.

    Science.gov (United States)

    Wannomae, Keith K; Christensen, Steven D; Micheli, Brad R; Rowell, Shannon L; Schroeder, Dave W; Muratoglu, Orhun K

    2010-06-01

    Wear and delamination of conventional ultrahigh-molecular-weight polyethylene (UHMWPE) components used in total knee arthroplasty can compromise long-term performance. Radiation cross-linking and melt-annealing reduced wear and increased delamination resistance of UHMWPE. An alternative material is the alpha-tocopherol-stabilized irradiated UHMWPE (alphaTPE), with improved mechanical and fatigue properties vs irradiated and melted UHMWPE. We studied the wear and delamination resistance of alphaTPE and conventional UHMWPE (direct compression molded GUR 1050 and Himont 1900) under reciprocating unidirectional motion. Wear resistance was improved, and no delamination was observed in alphaTPE. Accelerated aging did not alter the wear and delamination behavior of alphaTPE. The GUR 1050 UHMWPE showed delamination and pitting when subjected to unidirectional reciprocating motion after accelerated aging. Himont 1900 UHMWPE showed no delamination when subjected to unidirectional reciprocating motion after accelerated aging. alpha-Tocopherol-stabilized irradiated UHMWPE is advanced for use in total knee arthroplasty due to its high resistance to wear, delamination, and oxidation. Copyright 2010 Elsevier Inc. All rights reserved.

  11. Preparation, characterization and wear resistance to ceramic composites Si C/Ti B{sub 2}; Elaboration, caracterisation et resistance a l`usure de composites ceramiques SiC/TiB{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, C.

    1997-12-18

    The composites Si C-Ti B{sub 2} (5,10,15% vol. Ti B{sub 2}) have been synthesized by natural and reactive sintering from Ti O{sub 2}, B{sub 4} C and phenolic resin used as carbon source, by the reaction: Ti O{sub 2} + 0.5 B{sub 4} C +1.5 C -> Ti B{sub 2} + 2 CO (1400 degrees Celsius). They have been characterized from a microstructural, mechanical and tribological point of view. The dispersion of Ti B{sub 2} particles is very homogeneous in optical microscopy and in scanning electron microscopy. The images analysis has showed that most of the particles have a size smaller than 1 {mu}m. The atomic force microscopy and the transmission electron microscopy have revealed the existence of nanometrical particles. Concerning the mechanical properties, the fracture toughness increases with the Ti B{sub 2} rate and the hardness decreases. By friction, the composite materials wear slowly than the monolithic SiC. The wear mechanisms are modified in air and in water. In air, a layer of oxidized scraps, protector if it is stable, are formed for composites while there is formation of rollers for SiC. In water, composites are polished while SiC wears by cleavages. The influence of the Ti B{sub 2} phase on the wear resistance is due to the tribo-oxidation: a lubrication can take place through the tribo-oxidation products. (O.M.) 64 refs.

  12. Extracellular Proteins: Novel Key Components of Metal Resistance in Cyanobacteria?

    Science.gov (United States)

    Giner-Lamia, Joaquín; Pereira, Sara B; Bovea-Marco, Miquel; Futschik, Matthias E; Tamagnini, Paula; Oliveira, Paulo

    2016-01-01

    Metals are essential for all living organisms and required for fundamental biochemical processes. However, when in excess, metals can turn into highly-toxic agents able to disrupt cell membranes, alter enzymatic activities, and damage DNA. Metal concentrations are therefore tightly controlled inside cells, particularly in cyanobacteria. Cyanobacteria are ecologically relevant prokaryotes that perform oxygenic photosynthesis and can be found in many different marine and freshwater ecosystems, including environments contaminated with heavy metals. As their photosynthetic machinery imposes high demands for metals, homeostasis of these micronutrients has been widely studied in cyanobacteria. So far, most studies have focused on how cells are capable of controlling their internal metal pools, with a strong bias toward the analysis of intracellular processes. Ultrastructure, modulation of physiology, dynamic changes in transcription and protein levels have been studied, but what takes place in the extracellular environment when cells are exposed to an unbalanced metal availability remains largely unknown. The interest in studying the subset of proteins present in the extracellular space has only recently begun and the identification and functional analysis of the cyanobacterial exoproteomes are just emerging. Remarkably, metal-related proteins such as the copper-chaperone CopM or the iron-binding protein FutA2 have already been identified outside the cell. With this perspective, we aim to raise the awareness that metal-resistance mechanisms are not yet fully known and hope to motivate future studies assessing the role of extracellular proteins on bacterial metal homeostasis, with a special focus on cyanobacteria.

  13. Extracellular proteins: Novel key components of metal resistance in cyanobacteria?

    Directory of Open Access Journals (Sweden)

    Joaquin eGiner-Lamia

    2016-06-01

    Full Text Available Metals are essential for all living organisms and required for fundamental biochemical processes. However, when in excess, metals can turn into highly-toxic agents able to disrupt cell membranes, alter enzymatic activities and damage DNA. Metal concentrations are therefore tightly controlled inside cells, particularly in cyanobacteria. Cyanobacteria are ecologically relevant prokaryotes that perform oxygenic photosynthesis and can be found in many different marine and freshwater ecosystems, including environments contaminated with heavy metals. As their photosynthetic machinery imposes high demands for metals, homeostasis of these micronutrients has been widely studied in cyanobacteria. So far, most studies have focused on how cells are capable of controlling their internal metal pools, with a strong bias towards the analysis of intracellular processes. Ultrastructure, modulation of physiology, dynamic changes in transcription and protein levels have been studied, but what takes place in the extracellular environment when cells are exposed to an unbalanced metal availability remains largely unknown. The interest in studying the subset of proteins present in the extracellular space has only recently begun and the identification and functional analysis of the cyanobacterial exoproteomes are just emerging. Remarkably, metal-related proteins such as the copper-chaperone CopM or the iron-binding protein FutA2 have already been identified outside the cell. With this perspective, we aim to raise the awareness that metal-resistance mechanisms are not yet fully known and hope to motivate future studies assessing the role of extracellular proteins on bacterial metal homeostasis, with a special focus on cyanobacteria.

  14. Effect of Multipath Laser Shock Processing on Microhardness, Surface Roughness, and Wear Resistance of 2024-T3 Al Alloy

    Directory of Open Access Journals (Sweden)

    Abdulhadi Kadhim

    2014-01-01

    Full Text Available Laser shock processing (LSP is an innovative surface treatment technique with high peak power, short pulse, and cold hardening for strengthening metal materials. LSP is based on the application of a high intensity pulsed laser beam (I>1 GW/cm2;  t<50 ns at the interface between the metallic target and the surrounding medium (a transparent confining material, normally water forcing a sudden vaporization of the metallic surface into a high temperature and density plasma that immediately develops inducing a shock wave propagating into the material. The shock wave induces plastic deformation and a residual stress distribution in the target material. In this paper we study the increase of microhardness and surface roughness with the increase of laser pulse energy in 2024-T3 Al alloy. The influence of the thickness of the confining layer (water on microhardness and surface roughness is also studied. In addition, the effect of LSP treatment with best conditions on wear behaviors of the alloy was investigated.

  15. Laser composite surfacing of A681 steel with WC + Cr + Co for improved wear resistance

    Directory of Open Access Journals (Sweden)

    Moisés Felipe Teixeira

    2017-01-01

    Full Text Available Laser surface alloying (LSA is a surface treatment technique. It involves the near surface melting by a powerful laser beam with a pre-deposited or concomitantly added alloying element along with a part of the underlying substrate to form a surface alloyed zone. In this paper, it is reported the treatment by laser surface alloying of a cold work steel ASTM A681 substrate simultaneously fed with a powder mixture of 86 wt.% WC + 8 wt.% Cr + 6 wt.% Co. It was carried out using a continuous wave λ = 1064 nm fiber-coupled diode laser with five different laser intensities – resulting in five specimens – and then studied and analyzed their microstructure, phases, composition and microhardness. One of these configurations was applied to enhance a deep drawing tool for automotive steel sheet stamping. The process modified the specimens near surface layer, from a ferritic structure into an austenitic matrix with a refined dendritic microstructure, with an enhanced surface hardness from 250 HV to ∼560 HV. The treated deep drawing tool showed remarkable wear improvement compared to a non-treated one after one thousand stamps. This result allows the process for industrial applications.

  16. Fault mechanism analysis and simulation for continuity resistance test of electrical components in aircraft engine

    Science.gov (United States)

    Shi, Xudong; Yin, Yaping; Wang, Jialin; Sun, Zhaorong

    2017-01-01

    A large number of electrical components are used in civil aircraft engines, whose electrical circuits are usually intricate and complicated. Continuity resistance is an important parameter for the operating state of electrical components. Electrical continuity fault has serious impact on the reliability of the aircraft engine. In this paper, mathematical models of electrical components are established, and simulation is made by Simulink to analyze the electrical continuity fault.

  17. Prediction of resistance development against drug combinations by collateral responses to component drugs

    DEFF Research Database (Denmark)

    Munck, Christian; Gumpert, Heidi; Nilsson Wallin, Annika

    2014-01-01

    to do so. Thus, predictive models are needed to rationally design resistance-limiting therapeutic regimens. Using adaptive evolution, we studied the resistance response of the common pathogen Escherichia coli to 5 different single antibiotics and all 10 different antibiotic drug pairs. By analyzing...... adaptation to the component drugs. Then, using engineered E. coli strains, we confirmed that drug resistance mutations that imposed collateral sensitivity were suppressed in a drug pair growth environment. These results provide a framework for rationally selecting drug combinations that limit resistance...

  18. Needs and challenges in precision wear measurement

    Energy Technology Data Exchange (ETDEWEB)

    Blau, P.J.

    1996-01-10

    Accurate, precise wear measurements are a key element in solving both current wear problems and in basic wear research. Applications range from assessing durability of micro-scale components to accurate screening of surface treatments and thin solid films. Need to distinguish small differences in wear tate presents formidable problems to those who are developing new materials and surface treatments. Methods for measuring wear in ASTM standard test methods are discussed. Errors in using alterate methods of wear measurement on the same test specimen are also described. Human judgemental factors are a concern in common methods for wear measurement, and an experiment involving measurement of a wear scar by ten different people is described. Precision in wear measurement is limited both by the capabilities of the measuring instruments and by the nonuniformity of the wear process. A method of measuring wear using nano-scale indentations is discussed. Current and future prospects for incorporating advanced, higher-precision wear measurement methods into standards are considered.

  19. Prediction of Wear in Crosslinked Polyethylene Unicompartmental Knee Arthroplasty

    Directory of Open Access Journals (Sweden)

    Jonathan Netter

    2015-05-01

    Full Text Available Wear-related complications remain a major issue after unicompartmental arthroplasty. We used a computational model to predict knee wear generated in vitro under diverse conditions. Inverse finite element analysis of 2 different total knee arthroplasty designs was used to determine wear factors of standard and highly crosslinked polyethylene by matching predicted wear rates to measured wear rates. The computed wear factor was used to predict wear in unicompartmental components. The articular surface design and kinematic conditions of the unicompartmental and tricompartmental designs were different. Predicted wear rate (1.77 mg/million cycles was very close to experimental wear rate (1.84 mg/million cycles after testing in an AMTI knee wear simulator. Finite element analysis can predict experimental wear and may reduce the cost and time of preclinical testing.

  20. Artificial Neural Networks for the Prediction of Wear Properties of Al6061-TiO2 Composites

    Science.gov (United States)

    Veeresh Kumar, G. B.; Pramod, R.; Shivakumar Gouda, P. S.; Rao, C. S. P.

    2017-08-01

    The exceptional performance of composite materials in comparison with the monolithic materials have been extensively studied by researchers. Among the metal matrix composites Aluminium matrix based composites have displayed superior mechanical properties. The aluminium 6061 alloy has been used in aeronautical and automotive components, but their resistance against the wear is poor. To enhance the wear properties, Titanium dioxide (TiO2) particulates have been used as reinforcements. In the present investigation Back propagation (BP) technique has been adopted for Artificial Neural Network [ANN] modelling. The wear experimentations were carried out on a pin-on-disc wear monitoring apparatus. For conduction of wear tests ASTM G99 was adopted. Experimental design was carried out using Taguchi L27 orthogonal array. The sliding distance, weight percentage of the reinforcement material and applied load have a substantial influence on the height damage due to wear of the Al6061 and Al6061-TiO2 filled composites. The Al6061 with 3 wt% TiO2 composite displayed an excellent wear resistance in comparison with other composites investigated. A non-linear relationship between density, applied load, weight percentage of reinforcement, sliding distance and height decrease due to wear has been established using an artificial neural network. A good agreement has been observed between experimental and ANN model predicted results.

  1. New directions in lubrication, materials, wear, and surface interactions - Tribology in the 80's

    Science.gov (United States)

    Loomis, W. R. (Editor)

    1985-01-01

    New directions in tribology are described. A range of topics is addressed, extending from fundamental research on tribological materials of all kinds and their surface effects, to final technological applications in mechanical components such as bearings, gears, and seals. The general topics addressed include: importance and definition of materials in tribology; future directions of research in adhesion and friction, wear and wear-resistant materials, and liquid lubricants and additives; status and new directions in elastohydrodynamic lubrication and solid lubricants; and tribological materials for mechanical components of the future.

  2. Sliding wear of conventional and nanostructured cemented carbides

    Energy Technology Data Exchange (ETDEWEB)

    Jia, K. [Stevens Inst. of Tech., Hoboken, NJ (United States). Dept. of Materials Science and Engineering; Fischer, T.E. [Stevens Inst. of Tech., Hoboken, NJ (United States). Dept. of Materials Science and Engineering

    1997-03-01

    The sliding wear mechanisms of cemented carbide and the effects of the microstructure scale on the wear resistance were investigated by performing a series of unlubricated sliding wear tests in air with pins of WC-Co composites sliding against silicon nitride disks. In the first approximation, the wear rate is proportional to the hardness with a wear coefficient k=6.9x10{sup -6} for all materials. In the conventional cermets, the wear coefficient k also depends on the grain size; materials with smaller WC grains exhibit a smaller wear resistance. This reduction, however, does not extend to the nanostructured materials which exhibit the above value for k: Their wear resistance is higher than that of conventional cermets in proportion to their hardness. The data can also be expressed in terms of cobalt content: The lower the cobalt content, the lower the wear; but two different such dependencies exist, one for the conventional and one for the nanostructured materials with lower wear. The sliding wear of WC-Co composites occurs on a very small scale: The worn surfaces show no evidence of fracture of plastic deformation. This wear behavior is explained by the hexagonal structure and the anisotropic mechanical behavior of the WC grains that are capable of shear in a limited number of planes but are not capable of triaxial deformation. The higher wear resistance of the nanostructured composites is related to their hardness which decreases the real area of contact. (orig.)

  3. Weight of polyethylene wear particles is similar in TKAs with oxidized zirconium and cobalt-chrome prostheses.

    Science.gov (United States)

    Kim, Young-Hoo; Kim, Jun-Shik; Huh, Wansoo; Lee, Kwang-Hoon

    2010-05-01

    The greater lubricity and resistance to scratching of oxidized zirconium femoral components are expected to result in less polyethylene wear than cobalt-chrome femoral components. We examined polyethylene wear particles in synovial fluid and compared the weight, size (equivalent circle diameter), and shape (aspect ratio) of polyethylene wear particles in knees with an oxidized zirconium femoral component with those in knees with a cobalt-chrome femoral component. One hundred patients received an oxidized zirconium femoral component in one knee and a cobalt-chrome femoral component in the other. There were 73 women and 27 men with a mean age of 55.6 years (range, 44-60 years). The minimum followup was 5 years (mean, 5.5 years; range, 5-6 years). Polyethylene wear particles were analyzed using thermogravimetric methods and scanning electron microscopy. The weight of polyethylene wear particles produced at the bearing surface was 0.0223 +/- 0.0054 g in 1 g synovial fluid in patients with an oxidized zirconium femoral component and 0.0228 +/- 0.0062 g in patients with a cobalt-chrome femoral component. Size and shape of polyethylene wear particles were 0.59 +/- 0.05 microm and 1.21 +/- 0.24, respectively, in the patients with an oxidized zirconium femoral component and 0.52 +/- 0.03 microm and 1.27 +/- 0.31, respectively, in the patients with a cobalt-chrome femoral component. Knee Society knee and function scores, radiographic results, and complication rate were similar between the knees with an oxidized zirconium and cobalt-chrome femoral component. The weight, size, and shape of polyethylene wear particles were similar in the knees with an oxidized zirconium and a cobalt-chrome femoral component. We found the theoretical advantages of this surface did not provide the actual advantage. Level I, therapeutic study. See the guidelines for Authors for a complete description of levels of evidence.

  4. Wear behaviour of Al 261

    Directory of Open Access Journals (Sweden)

    N. Mathan Kumar

    2016-03-01

    Full Text Available Al 2618 matrix material was mixed with the Silicon Nitride (Si3N4, Aluminium Nitride (AlN and Zirconium Boride (ZrB2 reinforced particles. AMC was synthesized successfully by the stir casting method with the various X-wt.% of reinforcements (X = 0,2,4,6,8. Tribological behaviour was studied in this composite with various temperature conditions. The working conditions were Temperature (°C, Load (N, Velocity (m/s and Sliding Distances (m. Before wear testing the mechanical behaviour has been analysed. EDAX was confirmed by the matrix material composition. The Al 2618 alloy and the reinforcement mixers were confirmed by the X-ray Diffraction analysis. Wear rate (mm3/m, Wear resistance (m/mm3, Specific Wear rate (m/Nm and Co-efficient of friction (μ were analysed with various conditions. The worn surfaces were analysed before and after wear testing by Scanning Electron Microscope (SEM. Influence of process parameters and Percentage of contribution were analysed by Taguchi and Analysis of Variance (ANOVA methods. Genetic Algorithm (GA was adopted for optimizing the best and mean of the wear rate and to identify the exact influence of input parameters.

  5. Wear rate control of peek surfaces modified by femtosecond laser

    Science.gov (United States)

    Hammouti, S.; Pascale-Hamri, A.; Faure, N.; Beaugiraud, B.; Guibert, M.; Mauclair, C.; Benayoun, S.; Valette, S.

    2015-12-01

    This paper presents the effect of laser texturing on the tribological properties of PEEK surfaces under a ball-on-flat contact configuration. Thus, surfaces with circular dimples of various diameters and depth were created. Tests were conducted with a normal load of 5 N and a sliding velocity of 0.01 m s-1, using bovine calf serum at 37.5 °C as a lubricant. The tribological conditions including the sliding frequency and the lubricant viscosity indicate that tests were performed under boundary lubrication regime. Results showed that discs with higher dimple depth exhibited higher friction coefficient and caused more abrasive wear on the ball specimen. Nevertheless, tribosystems (ball and disc) with dimpled disc surfaces showed a higher wear resistance. In the frame of our experiments, wear rates obtained for tribosystems including dimpled surfaces were 10 times lower than tribosystems including limited patterned or untextured surfaces. Applications such as design of spinal implants may be concerned by such a surface treatment to increase wear resistance of components.

  6. Sorghum Resistance to the Sugarcane Aphid, Melanaphis sacchari (Zehntenr) Amounts of Surface Wax and Nutritional Components

    OpenAIRE

    積木, 久明; 兼久, 勝夫; Moharramipour, Saeid

    1995-01-01

    The differences in the amounts of leaf surface wax and nutritional components such as sugar and free amino acids were compared among resistant (PE 954177), moderately resistant (IS 84) and susceptible (Redlan B) sorghum varieties to the sugarcane aphid. Melanaphis sacchari (Zehntner). (1) The kind of aphid appearing on the leaves of the sorghum varieties was only the sugarcane aphid, Melanaphis sacchari in the field. The number of aphids infesting a leaf was ca 0,30 and 3,500 in the resistant...

  7. Wear Characteristics of Polymer -Based Composites

    Science.gov (United States)

    Şahin, Y.; Mirzayev, H.

    2015-11-01

    The dry wear of polytetrafluoroethylene (PTFE)-based composites, including bronze-filled composites (B60), glass-filled composites (G15), and carbon-filled composites (C25), produced by the mold casting method were investigated under different sliding conditions. The Taguchi L27 method and the analysis of variance were used to identify the effect of process parameters on the wear of tested materials. Experimental results showed that the wear resistance of G15 polymer composites was better than those of C25 and B60 ones. The specific wear rate decreased with increasing sliding distance and load, but partly decreased with increasing tensile strength.

  8. Analytical Assessment of the Blast Resistance of Precast, Prestressed Concrete Components (PREPRINT)

    Science.gov (United States)

    2007-04-01

    AFRL-ML-TY-TP-2007-4529 PREPRINT ANALYTICAL ASSESSMENT OF THE BLAST RESISTANCE OF PRECAST, PRESTRESSED CONCRETE COMPONENTS Nicholas...Precast, Prestressed Concrete Components Nicholas Cramsey1 and Clay Naito2 SYNOPSIS Four blast tests were performed on 30-ft (9.1-m) tall precast... prestressed concrete wall panels. Two conventional sandwich panels and a control panel were examined and shown to perform adequately under the blast

  9. Investigation of silicon carbon nitride nanocomposite films as a wear resistant layer in vitro and in vivo for joint replacement applications.

    Science.gov (United States)

    Liang, Y; Liu, D G; Bai, W Q; Tu, J P

    2017-05-01

    Silicon-contained CNx nanocomposite films were prepared using the ion beam assisted magnetron sputtering under different nitrogen gas pressure. With increase of the nitrogen pressure, silicon and nitrogen content of the CNx films drastically increase, and is saturated as the PN2 reach about 40%. Surface roughness and the contact angle are increase, while the friction coefficient decreased. The CNx film with 5.7at.% Si content possess the lowest friction coefficient of only 0.07, and exhibited the best tribological properties. The impact of CNx films with different silicon content on the growth and the activation of osteoblasts were compared to that of Ti6Al4V. The incorporation of silicon in the CNx film also showed an increase cell adhesion. Bonding structure and surface energy were determined to be the factors contributing to the improved biocompatibility. Macrophages attached to 5.7at.% Si contained CNx films down regulated their production of cytokines and chemokines. Moreover, employed with Si contained CNx coated joint replacements, which were implanted subcutaneously into Sprague-Dawley mice for up to 36days, the tissue reaction and capsule formation was significantly decreased compared to that of Ti6Al4V. A mouse implantation study demonstrated the excellent in vivo biocompatibility and functional reliability of wear resist layer for joint replacements with a Si doped a-CNx coating for 36days. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Nanomechanical properties, wear resistance and in-vitro characterization of Ta2O5 nanotubes coating on biomedical grade Ti-6Al-4V.

    Science.gov (United States)

    Sarraf, Masoud; Razak, Bushroa Abdul; Nasiri-Tabrizi, Bahman; Dabbagh, Ali; Kasim, Noor Hayaty Abu; Basirun, Wan Jefrey; Bin Sulaiman, Eshamsul

    2017-02-01

    Tantalum pentoxide nanotubes (Ta2O5 NTs) can dramatically raise the biological functions of different kinds of cells, thus have promising applications in biomedical fields. In this study, Ta2O5 NTs were prepared on biomedical grade Ti-6Al-4V alloy (Ti64) via physical vapor deposition (PVD) and a successive two-step anodization in H2SO4: HF (99:1)+5% EG electrolyte at a constant potential of 15V. To improve the adhesion of nanotubular array coating on Ti64, heat treatment was carried out at 450°C for 1h under atmospheric pressure with a heating/cooling rate of 1°Cmin(-)(1). The surface topography and composition of the nanostructured coatings were examined by atomic force microscopy (AFM) and X-ray electron spectroscopy (XPS), to gather information about the corrosion behavior, wear resistance and bioactivity in simulated body fluids (SBF). From the nanoindentation experiments, the Young's modulus and hardness of the 5min anodized sample were ~ 135 and 6GPa, but increased to ~ 160 and 7.5GPa, respectively, after annealing at 450°C. It was shown that the corrosion resistance of Ti64 plates with nanotubular surface modification was higher than that of the bare substrate, where the 450°C annealed specimen revealed the highest corrosion protection efficiency (99%). Results from the SBF tests showed that a bone-like apatite layer was formed on nanotubular array coating, as early as the first day of immersion in simulated body fluid (SBF), indicating the importance of nanotubular configuration on the in-vitro bioactivity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Gear Tooth Wear Detection Algorithm

    Science.gov (United States)

    Delgado, Irebert R.

    2015-01-01

    Vibration-based condition indicators continue to be developed for Health Usage Monitoring of rotorcraft gearboxes. Testing performed at NASA Glenn Research Center have shown correlations between specific condition indicators and specific types of gear wear. To speed up the detection and analysis of gear teeth, an image detection program based on the Viola-Jones algorithm was trained to automatically detect spiral bevel gear wear pitting. The detector was tested using a training set of gear wear pictures and a blind set of gear wear pictures. The detector accuracy for the training set was 75 percent while the accuracy for the blind set was 15 percent. Further improvements on the accuracy of the detector are required but preliminary results have shown its ability to automatically detect gear tooth wear. The trained detector would be used to quickly evaluate a set of gear or pinion pictures for pits, spalls, or abrasive wear. The results could then be used to correlate with vibration or oil debris data. In general, the program could be retrained to detect features of interest from pictures of a component taken over a period of time.

  12. The atypical resistance gene, RPW8, recruits components of basal defence for powdery mildew resistance in Arabidopsis.

    Science.gov (United States)

    Xiao, Shunyuan; Calis, Ozer; Patrick, Elaine; Zhang, Guangmin; Charoenwattana, Piyavadee; Muskett, Paul; Parker, Jane E; Turner, John G

    2005-04-01

    Genetic studies have identified a number of components of signal transduction pathways leading to plant disease resistance and the accompanying hypersensitive response (HR) following detection of pathogens by plant resistance (R) genes. In Arabidopsis, the majority of R proteins so far characterized belong to a plant superfamily that have a central nucleotide-binding site and C-terminal leucine-rich-repeats (NB-LRRs). Another much less prevalent class comprises RPW8.1 and RPW8.2, two related proteins that possess a putative N-terminal transmembrane domain and a coiled-coil motif, and confer broad-spectrum resistance to powdery mildew. Here we investigated whether RPW8.1 and RPW8.2 engage known pathway(s) for defence signalling. We show that RPW8.1 and RPW8.2 recruit, in addition to salicylic acid and EDS1, the other NB-LRR gene-signalling components PAD4, EDS5, NPR1 and SGT1b for activation of powdery mildew resistance and HR. In contrast, NDR1, RAR1 and PBS3 that are required for function of certain NB-LRR R genes, and COI1 and EIN2 that operate, respectively, in the jasmonic acid and ethylene signalling pathways, do not contribute to RPW8.1 and RPW8.2-mediated resistance. We further demonstrate that EDR1, a gene encoding a conserved MAPKK kinase, exerts negative regulation on HR cell death and powdery mildew resistance by limiting the transcriptional amplification of RPW8.1 and RPW8.2. Our results suggest that RPW8.1 and RPW8.2 stimulate a conserved basal defence pathway that is negatively regulated by EDR1.

  13. Experimental dissection of oxygen transport resistance in the components of a polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Oh, Hwanyeong; Lee, Yoo il; Lee, Guesang; Min, Kyoungdoug; Yi, Jung S.

    2017-03-01

    Oxygen transport resistance is a major obstacle for obtaining high performance in a polymer electrolyte membrane fuel cell (PEMFC). To distinguish the major components that inhibit oxygen transport, an experimental method is established to dissect the oxygen transport resistance of the components of the PEMFC, such as the substrate, micro-porous layer (MPL), catalyst layer, and ionomer film. The Knudsen numbers are calculated to determine the types of diffusion mechanisms at each layer by measuring the pore sizes with either mercury porosimetry or BET analysis. At the under-saturated condition where condensation is mostly absent, the molecular diffusion resistance is dissected by changing the type of inert gas, and ionomer film permeation is separated by varying the inlet gas humidity. Moreover, the presence of the MPL and the variability of the substrate thickness allow the oxygen transport resistance at each component of a PEMFC to be dissected. At a low relative humidity of 50% and lower, an ionomer film had the largest resistance, while the contribution of the MPL was largest for the other humidification conditions.

  14. Different Impacts of Metabolic Syndrome Components on Insulin Resistance in Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Chung-Hua Hsu

    2013-01-01

    Full Text Available Objective. To examine the different impacts of MS components on insulin resistance in type 2 diabetes. Methods. A number of subjects (144 who met the criteria of (1 age between 30 and 75 years, (2 had type 2 diabetes for more than one year, and (3 taking gliclazide and metformin for more than 6 months were enrolled. All subjects were assigned to one of the four HOMA index categories. The HOMA index quartile 4 denotes the highest insulin resistance. The main outcome evaluated is the odds ratios (ORs of different MS components on HOMA index quartile 4. The characteristics in HOMA index quartiles and groups of nonmetabolic syndrome (NMS; number of components 2 were also evaluated. Results. The results showed that both MSA and MSB groups had higher ORs (5.9 and 13.8 times, resp. than the NMS group; and that subjects with large waist circumference (LWC and high triglyceride (HTG level have higher ORs (6.1 and 2.6 times, resp. in developing higher insulin resistance than normal control subjects. Conclusion. Type 2 diabetic patients with greater number of MS components have higher ORs in developing increased insulin resistance.

  15. Influence of silicon content and heat treatment on wear resistance of white chromium cast irons under high speed solidification conditions; Influencia del contenido de silicio y el tratamiento termico en la resistencia al desgaste de fundiciones blancas al cromo en condiciones de rapida solidificacion

    Energy Technology Data Exchange (ETDEWEB)

    Goyo, L.; Varela, A.; Verhaege, M.; Garcia, A.; Mier, J.; Moors, M.

    2012-11-01

    The influence of silicon content and heat treatment on microstructure, abrasive and dry friction wear resistance of a 3 % C, 12 % Cr cast iron, under fast solidification conditions is studied. The fast solidification condition diminishes the carbide volume and the silicon content increases their dispersion and finesses. All matrixes obtained were perlitics, whit different finesses. No intermediate transformation products were noticed. Hardness had little variation. Austenization treatment show little effectivity, with tendency to increase wear in reference to as cast and maintenance treatments. Behavior under dry friction and abrasive wear were similar under test conditions applied whit more influence of carbide morphology in the abrasive wear conditions. (Author) 32 refs.

  16. Comparative study of the wear resistance of Al2O3-coated MA956 superalloy

    Directory of Open Access Journals (Sweden)

    Canahua Loza, Hugo

    2000-10-01

    Full Text Available Preoxidation of the MA956 superalloy, proposed as a prosthetic biomaterial, generates a compact and inert a-alumina surface layer. The aim of this study is to assess the wear resistance provided by this alumina layer on the MA956 alloy in comparison with the same coated alloy and versus high density polyethylene. Comparative wear tests were carried out in both dry and wet conditions using the couples MA956/MA956, MA956/UHMWPE (ultra high molecular weight polyethylene and 316LVM/UHMWPE. The results corresponding to the couples MA956/MA956, with and without alumina layer, show that the load has more significant effect than the rotation speed on the weight loss and on the roughness. On the other hand the alumina surface layer provides a clear wear protection. The weight losses of the MA956 specimen in this couple are ten times lower when testing under wet conditions than under dry conditions. The MA956/UHMWPE couple behaves much better than the 316LVM/UHMWPE, as it presents the lowest values of friction coefíicient and weight losses of the MA956 specimen. These are only detectable after 70,000 cycles under a 70 MPa contact pressure. This couple offers the best guarantee of a prolonged service life for articulated parts in a prosthesis.

    La superaleación MA956, que se ha propuesto como biomaterial para prótesis osteoarticulares genera, mediante un adecuado tratamiento de preoxidación, una capa superficial, compacta e inerte, de alúmina alfa. El objetivo del presente trabajo es el estudio de la resistencia al desgaste de esta capa de alúmina, cuando se encuentra en contacto con la propia aleación recubierta y con polietileno de alta densidad. Se realizaron ensayos comparativos de desgaste, tanto en seco como en húmedo, con los pares MA956/MA956, MA956/UHMWPE (polietileno de muy elevado peso molecular y 316LVM/UHMWPE. Los resultados obtenidos con el par MA956/MA956, con y sin capa de alúmina, indican que la carga es el factor de mayor

  17. Structurally Integrated Coatings for Wear and Corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Beardsley, M. Brad; Sebright, Jason L.

    2008-11-18

    techniques, balanced with overall materials performance. State-of-the-art design and simulation capabilities were used to guide materials and process refinement. Caterpillar was the lead of the multi-partner collaborative project. Specific tasks were performed by the partners base on their unique capabilities. The project team was selected to include leaders in the field of material development, processing, modeling, and material characterization. Specifically, industrial members include the suppliers Deloro Stellite and Powder Alloy Corporation., who provided the experimental alloys and who aided in the development of the costs for the alloys, the Missouri University of Science and Technology and Iowa State University, who provided help in the alloy development and material characterization, QuesTek Innovations, a small company specializing the microstructural modeling of materials, and the DOE laboratories, Oak Ridge National Laboratory and National Energy Technology Laboratory (Albany), who provided unique coating process capability and wear characterization testing. The technologies developed in this program are expected to yield energy savings of about 50% over existing technologies, or 110 trillion BTUs per year by 2020 when fully implemented. Primary applications by Caterpillar are to replace the surface of machine components which are currently carburized and heat treated with new cladding materials with double the wear life. The new cladding technologies will consume less energy than carburizing. Thus, nearly 50% energy savings can be expected as a result from elimination of the heat treat process and the reduce wear of the materials. Additionally, when technologies from this project are applied on titanium or other non-ferrous substrates to make lighter weight, more wear resistant, and more efficient structures, significant fuel savings can be realized. With the anticipated drastic reduction in cost for refining titanium-containing ores, the usage of titanium

  18. Análise da resistência ao desgaste de revestimento duro aplicado por soldagem em facas picadoras de cana-de-açúcar Analysis of wear resistance of hardfacing applied by welding in sugarcane shredder knife

    Directory of Open Access Journals (Sweden)

    Aldemi Coelho Lima

    2010-06-01

    cost is high due to metallic losses by wear. This paper studies the application of hardfacings by flux cored arc welding on the wear resistance of sugarcane shredder knives comparing laboratory and field-test results. Four types of consumable were used: three selfshielded flux cored wires of diameter 1.6 mm of alloys FeCrC, FeCrC+Nb and FeCrC+Ti and a covered electrode of FeCrC alloy of diameter 4.0 mm. The base metal is SAE 1020 steel. Test specimens were evaluated using rubber wheel abrasion tests (ASTM G65. Sugarcane shredder knives hardfaced in the same welding conditions were also tested on a shredder in an alcohol distillery. Wear evaluation is by mass loss. The flux cored wires were welded in short-circuit transfer mode with the same current and voltage values. The wire with Nb had the highest wear resistance in laboratory test but due to cracks and spalling had the least wear resistance in field test. The FeCrC and FeCrC+Ti wires presented the worst results in laboratory tests and the best results in field test, respectively. In comparison with the covered electrode, the FeCrC+Nb wire presented similar performance in laboratory and the FeCrC+Ti wire presented similar performance in field tests.

  19. A third component of the human cytomegalovirus terminase complex is involved in letermovir resistance.

    Science.gov (United States)

    Chou, Sunwen

    2017-12-01

    Letermovir is a human cytomegalovirus (CMV) terminase inhibitor that was clinically effective in a Phase III prevention trial. In vitro studies have shown that viral mutations conferring letermovir resistance map primarily to the UL56 component of the terminase complex and uncommonly to UL89. After serial culture of a baseline CMV laboratory strain under letermovir, mutation was observed in a third terminase component in 2 experiments, both resulting in amino acid substitution P91S in gene UL51 and adding to a pre-existing UL56 mutation. Recombinant phenotyping indicated that P91S alone conferred 2.1-fold increased letermovir resistance (EC50) over baseline, and when combined with UL56 mutation S229F or R369M, multiplied the level of resistance conferred by those mutations by 3.5-7.7-fold. Similarly a combination of UL56 mutations S229F, L254F and L257I selected in the same experiment conferred 54-fold increased letermovir EC50 over baseline, but 290-fold when combined with UL51 P91S. The P91S mutant was not perceptibly growth impaired. Although pUL51 is essential for normal function of the terminase complex, its biological significance is not well understood. Letermovir resistance mutations mapping to 3 separate genes, and their multiplier effect on the level of resistance, suggest that the terminase components interactively contribute to the structure of a letermovir antiviral target. The diagnostic importance of the UL51 P91S mutation arises from its potential to augment the letermovir resistance of some UL56 mutations at low fitness cost. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. DEVELOPMENT OF WEAR RESISTANT COATINGS FORMED BY PLASMA SPRAYING OF ALLOY Ni–Fe–Cr–Si–B–C SYSTEM REINFORCED WITH CERAMICS Al2O3

    Directory of Open Access Journals (Sweden)

    A. S. Kalinichenko

    2016-01-01

    Full Text Available . Creating a functionally oriented, including nanostructured, anti-friction materials and coatings with qualitatively new complex of service properties is an important scientific and practical problem. In particular, for the cable industry it is urgent task of ensuring the high performance properties of fast deteriorating stretching and supporting rollers. Working surfaces of these parts operate under practically dry friction conditions with constantly updated material of stretching wire. Plasma spraying is one of the widely used methods of surface engineering to create wear resistant coatings and which is characterized with process flexibility and the ability to create coatings using various materials and alloys including composite ones. The installation UPU-3D with the PP-25 plasma torch was used for plasma spraying. The thickness of the sprayed layer was 0.8–1.1 mm. As a material for the deposition of composite coatings a powder mixture of self-fluxing nickel alloy PG-HN80SR4 (system Ni–Fe–Cr–Si–B–C and a neutral oxide ceramics Al2O3 was used. The amount of ceramics varied from 15 to 33 %. This ceramic oxide was selected due to the desire to reduce coatings’ costs while providing high durability. Carried out phase and microstructural studies have shown when ceramics was added in an amount more than 20 % a formation of conglomerates formed by not melted alumina particles often was observed. These conglomerates serve as crack formation centers in the coating. The phase composition of the coatings practically does not depend on the content of ceramics compounds. Tribological tests have shown that the best results were obtained when the content of the oxide ceramic in the coating was in the range from 15 to 20 %.

  1. Evaluation of polymerization shrinkage, polymerization shrinkage stress, wear resistance, and compressive strength of a silorane-based composite: A finite element analysis study

    Directory of Open Access Journals (Sweden)

    Suresh Mitthra

    2017-01-01

    Full Text Available Background: Understanding the mechanical properties is important in predicting the clinical behavior of composites. Finite element analysis (FEA evaluates properties of materials replicating clinical scenario. Aim: This study evaluated polymerization shrinkage and stress, wear resistance (WR, and compressive strength (CS of silorane in comparison with two methacrylate resins. Settings and Design: This study design was a numerical study using FEA. Materials and Methods: Three-dimensional (3D models of maxillary premolar with Class I cavities (2 mm depth, 4 mm length, and 2.5 mm width created and restored with silorane, nanohybrid, and microhybrid; Groups I, II, and III, respectively. Loads of 200–600 N were applied. Polymerization shrinkage was first determined by displacement produced in the X, Y, and Z planes. Maximum stress distribution due to shrinkage was calculated using AN SYS software. 3D cube models of composite resins were simulated with varying filler particle size. Similar loads were applied. WR and compressive stress were calculated: K W L/H and load/cross-sectional area, respectively. Statistical analysis done using one-way ANOVA, Kruskal–Wallis, and Tukey's honestly significant difference test (P < 0.05. Results: Polymerization shrinkage (0.99% and shrinkage stress (233.21 Mpa of silorane were less compared to microhybrid (2.14% and 472.43 Mpa and nanohybrid (2.32% and 464.88 Mpa. Silorane (7.92×/1011 μm/mm3 and nanohybrid (7.79×/1011 showed superior WR than microhybrid (1.113×/1017. There was no significant difference in compressive stress among the groups. Conclusion: Silorane exhibited less polymerization shrinkage and shrinkage stress compared to methacrylates. Silorane and nanohybrid showed greater WR compared to microhybrid. CS of all groups was similar.

  2. Nanoclay-Reinforced Glass-Ionomer Cements: In Vitro Wear Evaluation and Comparison by Two Wear-Test Methods

    Directory of Open Access Journals (Sweden)

    Muhammad A. Fareed

    2017-10-01

    Full Text Available Glass ionomer cement (GIC represents a major transformation in restorative dentistry. Wear of dental restoratives is a common phenomenon and the determination of the wear resistance of direct-restorative materials is a challenging task. The aim of this paper was to evaluate the wear resistance of novel glass ionomer cement by two wear-test methods and to compare the two wear methods.The wear resistance of a conventional glass ionomer cement (HiFi Advanced Health Care Kent, UK and cements modified by including various percentages of nanoclays (1, 2 and 4 wt % was measured by a reciprocating wear test (ball-on-flat and Oregon Health and Sciences University’s (OHSU wear simulator. The OHSU wear simulation subjected the cement specimens to three wear mechanisms, namely abrasion, three-body abrasion and attrition using a steatite antagonist. The abrasion wear resulted in material loss from GIC specimen as the steatite antagonist forced through the exposed glass particles when it travelled along the sliding path.The hardness of specimens was measured by the Vickers hardness test. The results of reciprocation wear test showed that HiFi-1 resulted in the lowest wear volume 4.90 (0.60 mm3 (p < 0.05, but there was no significant difference (p > 0.05 in the wear volume in comparison to HiFi, HiFi-2 and HiFi-4. Similarly, the results of OHSU wear simulator showed that the total wear volume of HiFi-4 1.49 (0.24 was higher than HiFi-1 and HiFi-2. However, no significant difference (p > 0.05 was found in the OHSU total wear volume in GICs after nanoclay incorporation. The Vickers hardness (HV of the nanoclay-reinforced cements was measured between 62 and 89 HV. Nanoclay addition at a higher concentration (4% resulted in higher wear volume and wear depth. The total wear volumes were less dependent upon abrasion volume and attrition volume. The total wear depths were strongly influenced by attrition depth and to some extent by abrasion depth. The addition of

  3. The effect of microstructure on abrasive wear of steel

    Science.gov (United States)

    Kešner, A.; Chotëborský, R.; Linda, M.

    2017-09-01

    Abrasive wear of agricultural tools is one of the biggest problems in currently being. The amount of abrasive wear, depending on the microstructure, has been investigated in this work. Steels 25CrMo4 and 51CrV4 were used in this work to determine the effect of the microstructure on the abrasive wear. These steels are commonly used for components that have to withstand abrasive wear.SEM analysis was used to detect the microstructure. The standardized ASTM G65 method was used to compare the abrasive wear of steels. The results show that the abrasive wear depends on the microstructure of steels.

  4. Wear in human knees

    Directory of Open Access Journals (Sweden)

    M.L. Wang

    2015-06-01

    Full Text Available Wear occurs in natural knee joints and plays a pivotal factor in causing articular cartilage degradation in osteoarthritis (OA processes. Wear particles are produced in the wear process and get involved in inflammation of human knees. This review presents progresses in the mechanical and surface morphological studies of articular cartilages, wear particles analysis techniques for wear studies and investigations of human knee synovial fluid in wear of human knees. Future work is also included for further understanding of OA symptoms and their relations which may shed light on OA causes.

  5. Wear Characteristics of Metallic Biomaterials: A Review

    Directory of Open Access Journals (Sweden)

    Mohamed A. Hussein

    2015-05-01

    Full Text Available Metals are extensively used in a variety of applications in the medical field for internal support and biological tissue replacements, such as joint replacements, dental roots, orthopedic fixation, and stents. The metals and alloys that are primarily used in biomedical applications are stainless steels, Co alloys, and Ti alloys. The service period of a metallic biomaterial is determined by its abrasion and wear resistance. A reduction in the wear resistance of the implant results in the release of incompatible metal ions into the body that loosen the implant. In addition, several reactions may occur because of the deposition of wear debris in tissue. Therefore, developing biomaterials with high wear resistance is critical to ensuring a long life for the biomaterial. The aim of this work is to review the current state of knowledge of the wear of metallic biomaterials and how wear is affected by the material properties and conditions in terms of the type of alloys developed and fabrication processes. We also present a brief evaluation of various experimental test techniques and wear characterization techniques that are used to determine the tribological performance of metallic biomaterials.

  6. The RAR1 interactor SGT1, an essential component of R gene-triggered disease resistance.

    Science.gov (United States)

    Azevedo, Cristina; Sadanandom, Ari; Kitagawa, Katsumi; Freialdenhoven, Andreas; Shirasu, Ken; Schulze-Lefert, Paul

    2002-03-15

    Plant disease resistance (R) genes trigger innate immune responses upon pathogen attack. RAR1 is an early convergence point in a signaling pathway engaged by multiple R genes. Here, we show that RAR1 interacts with plant orthologs of the yeast protein SGT1, an essential regulator in the cell cycle. Silencing the barley gene Sgt1 reveals its role in R gene-triggered, Rar1-dependent disease resistance. SGT1 associates with SKP1 and CUL1, subunits of the SCF (Skp1-Cullin-F-box) ubiquitin ligase complex. Furthermore, the RAR1-SGT1 complex also interacts with two COP9 signalosome components. The interactions among RAR1, SGT1, SCF, and signalosome subunits indicate a link between disease resistance and ubiquitination.

  7. Structural Component Fabrication and Characterization of Advanced Radiation Resistant ODS Steel for Next Generation Nuclear Systems

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Sang Hoon; Kim, Young Chun; Jin, Hyun Ju; Choi, Byoung Kwon; Kang, Suk Hoon; Kim, Tae Kyu [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    In a sodium-cooled fast reactor (SFR), the coolant outlet temperature and peak temperature of the fuel cladding tube will be about 545 .deg. C and 700 .deg. C with 250 dpa of a very high neutron dose rate. To realize this system, it is necessary to develop an advanced structural material having high creep and irradiation resistance at high temperatures. Austenitic stainless steel may be one of the candidates because of good strength and corrosion resistance at the high temperatures, however irradiation swelling severely occurred to 120dpa at high temperatures and this eventually leads to a decrease of the mechanical properties and dimensional stability. Advanced radiation resistant ODS steel (ARROS) has been newly developed for the in-core structural components in SFR, which has very attractive microstructures to achieve both superior creep and radiation resistances at high temperatures [4]. Nevertheless, the use of ARROS as a structural material essentially requires the fabrication technology development for component parts such as sheet, plate and tube. In this study, plates and tubes were tentatively fabricated with a newly developed alloy, ARROS. Microstructures as well as mechanical properties were also investigated to determine the optimized condition of the fabrication processes.

  8. Association among Fibrinolytic Proteins, Metabolic Syndrome Components, Insulin Secretion, and Resistance in Schoolchildren

    Directory of Open Access Journals (Sweden)

    Jin-Shuen Chen

    2015-01-01

    Full Text Available We investigated the role of urokinase plasminogen activator (uPA and its soluble receptors (suPAR and plasminogen activator inhibitor-1 (PAI-1 in metabolic syndrome (MetS components, insulin secretion, and resistance in schoolchildren. We enrolled 387 children, aged 10.3 ± 1.5 years, in Taipei. Anthropometry, fibrinolytic proteins, MetS components, insulin secretion, and resistance were measured. Subjects were divided into normal, overweight, and obese groups. Finally, the relationship between fibrinolytic proteins and metabolic syndrome in boys and girls was analyzed. In boys, PAI-1 was positively associated with body mass index (BMI percentile, hypertriglyceride, insulin secretion, and resistance. In girls, PAI-1 was positively associated with obesity, hypertriglyceridemia, and insulin secretion. In girls, uPA was positively associated with insulin secretion. suPAR was positively associated with high-sensitivity C-reactive protein in both boys and girls, and with BMI percentile and body fat in girls. The obese boys had higher suPAR and PAI-1 levels than the normal group. The obese girls had higher uPA, suPAR, and PAI-1 than the normal group. Boys and girls with MetS had higher PAI-1. Fibrinolytic proteins, especially PAI-1, are associated with MetS components and insulin secretion in children. Fibrinolytic proteins changes were more likely to occur in girls than in boys.

  9. The hardness and sliding wear behaviour of a bainitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Shipway, P.H. [Nottingham Univ. (United Kingdom). Dept. of Materials Engineering and Materials Design; Wood, S.J. [Nottingham Univ. (United Kingdom). Dept. of Materials Engineering and Materials Design; Dent, A.H. [Nottingham Univ. (United Kingdom). Dept. of Materials Engineering and Materials Design

    1997-03-01

    High-strength bainitic steels have a number of desirable mechanical properties and have thus been viewed as candidate materials for heavy wear applications. This work examines the role of transformation temperature on the wear resistance of isothermally formed bainite from a single alloy steel and compares it with wear resistance following other heat treatments such as quenching, quenching and tempering and normalisation. The sliding wear resistance was examined for a range of applied loads at a constant sliding velocity of 1 m s{sup -1}. Microstructural constituents of the steels were related to their wear resistance. The hardness of the bainitic steel was a function of the isothermal transformation temperature and its variation has been correlated with the transformation behaviour. However, the hardness of the materials did not correlate well with their wear resistance, with the hardest martensitic steel showing greater wear rates than the normalised steel. Bainitic microstructures formed at low transformation temperatures were found to have a high wear resistance which in many cases was a factor of two better than any of the other microstructures examined; this material had a good combination of hardness and toughness on the microstructural level due to the fine nature of the bainite formed with high dislocation density and the lack of embrittling martensite and cementite phases and it is proposed that these attributes confer its high wear resistance. (orig.)

  10. Asymmetric motion distribution between components of a mobile-core lumbar disc prosthesis: an explanation of unequal wear distribution in explanted CHARITÉ polyethylene cores.

    Science.gov (United States)

    Patwardhan, Avinash G; Havey, Robert M; Wharton, Nicholas D; Tsitsopoulos, Parmenion P; Newman, Patrick; Carandang, Gerard; Voronov, Leonard I

    2012-05-02

    The biconvex mobile core of the CHARITÉ lumbar disc prosthesis forms two joints (spherical bearings) with the metal end plates. We quantified the intra-prosthesis motion to test the hypothesis that the total prosthesis motion would not be equally distributed between the two bearings of implanted CHARITÉ discs, which might explain the unequal wear distribution reported in explanted cores. The hypothesis was tested by studying the flexion-extension motion responses of (1) twenty-six monosegmental CHARITÉ III discs implanted in nineteen human cadaveric lumbar spines, and (2) twenty-one CHARITÉ III discs (fifteen monosegmental, six bisegmental) implanted in eighteen patients in other published clinical studies. Intra-prosthesis motions were quantified with use of a radiographic image analysis technique. Eighty-eight percent of the CHARITÉ discs implanted in cadaveric specimens exhibited larger motion at the superior bearing, with 54% demonstrating more than twice as much motion at the superior bearing as at the inferior bearing. The ratio of motion at the superior bearing to motion at the inferior bearing averaged 2.68 ± 1.84, which was significantly larger than 1.0 (p cases and 2.55 ± 2.66 for all cases; both ratios were significantly larger than 1.0 (p < 0.05). We found preferentially larger motion at the superior bearing of the CHARITÉ discs implanted in human cadaveric lumbar spines and in patients, regardless of the implanted level.

  11. Nitrocarburizing for wear, corrosion, and fatigue

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, G. [Durferrit GmbH Thermotechnik, Hanau (Germany)

    1996-04-01

    Demands for higher strength and corrosion resistance at higher temperatures cannot always be met by advanced materials and designs alone. In many cases, surface engineering can provide required properties and extend service life. A thermochemical surface engineering treatment has been developed that improves the dynamic strength of parts and overcomes many corrosion and wear problems. Known as Melonite, the process was developed by Durferrite GmbH Thermotechnik, and is used to enhance the surface properties of steel and iron parts. The quench, quench-polish, and quench-polish-quench salt bath nitrocarburizing system can provide surface layers with a range of beneficial properties. This article will discuss details of the Melonite process, component properties after treatment, the effects of raising or lowering treatment temperatures, and environmental impact.

  12. Component

    Directory of Open Access Journals (Sweden)

    Tibor Tot

    2011-01-01

    Full Text Available A unique case of metaplastic breast carcinoma with an epithelial component showing tumoral necrosis and neuroectodermal stromal component is described. The tumor grew rapidly and measured 9 cm at the time of diagnosis. No lymph node metastases were present. The disease progressed rapidly and the patient died two years after the diagnosis from a hemorrhage caused by brain metastases. The morphology and phenotype of the tumor are described in detail and the differential diagnostic options are discussed.

  13. Phenotypic Suppression of Streptomycin Resistance by Mutations in Multiple Components of the Translation Apparatus.

    Science.gov (United States)

    Carr, Jennifer F; Lee, Hannah J; Jaspers, Joshua B; Dahlberg, Albert E; Jogl, Gerwald; Gregory, Steven T

    2015-09-01

    The bacterial ribosome and its associated translation factors are frequent targets of antibiotics, and antibiotic resistance mutations have been found in a number of these components. Such mutations can potentially interact with one another in unpredictable ways, including the phenotypic suppression of one mutation by another. These phenotypic interactions can provide evidence of long-range functional interactions throughout the ribosome and its functional complexes and potentially give insights into antibiotic resistance mechanisms. In this study, we used genetics and experimental evolution of the thermophilic bacterium Thermus thermophilus to examine the ability of mutations in various components of the protein synthesis apparatus to suppress the streptomycin resistance phenotypes of mutations in ribosomal protein S12, specifically those located distant from the streptomycin binding site. With genetic selections and strain constructions, we identified suppressor mutations in EF-Tu or in ribosomal protein L11. Using experimental evolution, we identified amino acid substitutions in EF-Tu or in ribosomal proteins S4, S5, L14, or L19, some of which were found to also relieve streptomycin resistance. The wide dispersal of these mutations is consistent with long-range functional interactions among components of the translational machinery and indicates that streptomycin resistance can result from the modulation of long-range conformational signals. The thermophilic bacterium Thermus thermophilus has become a model system for high-resolution structural studies of macromolecular complexes, such as the ribosome, while its natural competence for transformation facilitates genetic approaches. Genetic studies of T. thermophilus ribosomes can take advantage of existing high-resolution crystallographic information to allow a structural interpretation of phenotypic interactions among mutations. Using a combination of genetic selections, strain constructions, and experimental

  14. Effects of the different frequencies and loads of ultrasonic surface rolling on surface mechanical properties and fretting wear resistance of HIP Ti-6Al-4V alloy

    Science.gov (United States)

    Li, G.; Qu, S. G.; Pan, Y. X.; Li, X. Q.

    2016-12-01

    The main purpose of this paper was to investigate the effects of the different frequencies and loads of multi-pass ultrasonic surface rolling (MUSR) on surface layer mechanical properties, microstructure and fretting friction and wear characteristics of HIP (hot isostatic pressing) Ti-6Al-4 V alloy. Some microscopic analysis methods (SEM, TEM and EDS) were used to characterize the modified surface layer of material after MUSR treatment. The results indicated that the material in sample surface layer experienced a certain extent plastic deformation, and accompanied by some dense dislocations and twins generation. Moreover surface microhardness and residual stress of samples treated by MUSR were also greatly improved compared with the untreated. The fretting friction and wear properties of samples treated by MUSR in different conditions are tested at 10 and 15 N in dry friction conditions. It could be found that friction coefficient and wear volume loss were significantly declined in the optimal result. The main wear mechanism of MUSR-treated samples included abrasive wear, adhesion and spalling.

  15. Comparative wear mapping techniques

    DEFF Research Database (Denmark)

    Alcock, J.; Sørensen, Ole Toft; Jensen, S.

    1996-01-01

    Pin-on-disc tests of tungsten carbide pins against silicon carbide discs were performed and wear rate, mechanism and friction maps constructed. Correlations were observed between the wear mode and the friction of the pin-disc interface, and between the qualitative incidence of disruptive wear mec...

  16. Wear Behavior of Fiber Laser Textured TiN Coatings in a Heavy Loaded Sliding Regime

    Directory of Open Access Journals (Sweden)

    Daniele Ugues

    2012-11-01

    Full Text Available In heavy loaded mating components, such as sliders and sliding bearings, guaranteeing the efficiency of lubricant films for long times during severe service conditions is very complicated. In this work, the benefits deriving from the use of fiber laser sources for surface texturing of very thin TiN coatings in severe wear working conditions were demonstrated. Evaluations of the laser textured dimples shape, geometry and density are given. Wear performance of the fiber laser textured surfaces was evaluated in discontinuous oil lubricated conditions with a flat contact. High normal load and low sliding speed were applied. Comparison tests were also performed on commercial TiN and WC/C coatings. In terms of average wear volume and maximum wear depth, Laser Surface Texturing of TiN provided respectively a 70% and a 45% reduction if compared to plain TiN. If compared to WC/C the wear resistance gains were lower but LST TiN maintained such benefits for longer wear runs. SEM analysis also revealed that the laser interaction provided a localized thermal cracking to the TiN coating. However, the sliding action caused very limited and localized coating fragmentation or delamination.

  17. Resistencia al desgaste de recubrimientos de bronce al aluminio producidos con técnica de proyección térmica//Wear resistance of aluminum bronze coatings produced by thermal spray

    Directory of Open Access Journals (Sweden)

    Dayan Carolina Cárdenas-Feria

    2015-09-01

    Full Text Available Se estudió la resistencia al desgaste adhesivo de recubrimientos de bronce al aluminio depositados con la técnica de proyección térmica por llama sobre bronce fosforado SAE 62. Los recubrimientos fueron fabricados variando las presiones parciales de los gases de combustión, oxígeno y acetileno. El material utilizado fue caracterizado estructuralmente mediante difracción de rayosX (X-ray diffraction, XRD y el estudio morfológico mediante microscopía electrónica de barrido (Scanning electron microscopy, SEM. La resistencia al desgaste adhesivo de los recubrimientos se determinó por medio del ensayo de bola sobre disco, utilizando como bola una esférica de acero 100Cr6. Los resultados obtenidos permiten establecer que los recubrimientos proyectados con una presión de oxigeno de 78 psi y una presión de acetileno de 8 psi presentan la mejor resistencia al desgaste en comparación a los tratamientos producidos. El modo de falla de desgaste en los recubrimientos producidos es discutido en esta investigación.Palabras clave: desgaste abrasivo y adhesivo,  proyección térmica,  recubrimientos.______________________________________________________________________________AbstractWe studied the adhesive wear resistance of aluminum bronze coatings deposited by thermal spray on phosphor bronze SAE 62 substrates. The coatings were deposited by varying the partial pressures of the combustion gases: oxygen and acetylene. The structural characterization was made through X-ray diffraction (XRD and the morphological analysis was performed by scanning electron microscopy (SEM. The adhesive wear resistance of the coatings was determined by the bole on disc test using a spherical ball made of steel 100Cr6 and with a diameter of 6 mm. The results obtained show that the coating projected with an oxygen pressure of 78 psi and an acetylene pressure of 8 psi have the better wear resistance compared with the substrate and the others treatments deposited

  18. Prediction of wear rates in comminution equipment

    DEFF Research Database (Denmark)

    Jensen, Lucas Roald Dörig; Fundal, Erling; Møller, Per

    2010-01-01

    Raw material comminution equipment may be exposed to excessive wear, which makes it difficult to operate minerals processing plants continuously because lengthy and unplanned shut-downs interrupt the overall process. In general, most comminution equipment is fine-tuned to operate at low vibrations...... and to achieve guaranteed performance. From an economical point of view, it is always preferred to replace all worn parts during the planned maintenance shutdowns. When operating comminution equipment, the wear rate receives little attention and is considered a secondary matter. However, experience shows......-resistant high chromium white cast iron (21988/JN/HBW555XCr21), a heat-treated wear resistant steel (Hardox 400) and a plain carbon construction steel (S235). Quartz, which accounts for the largest wear loss in the cement industry, was chosen as abrasive. Other process parameters such as velocity (1–7 m...

  19. Development of Advanced Surface Enhancement Technology for Decreasing Wear and Corrosion of Equipment Used for Mineral Processing

    Energy Technology Data Exchange (ETDEWEB)

    Daniel Tao; Craig A. Blue

    2004-08-01

    Equipment wear is a major concern in the mineral processing industry, which dramatically increases the maintenance cost and adversely affects plant operation efficiency. In this research, wear problems of mineral processing equipment including screens, sieve bends, heavy media vessel, dewatering centrifuge, etc., were identified. A novel surface treatment technology, high density infrared (HDI) surface coating process was proposed for the surface enhancement of selected mineral processing equipment. Microstructural and mechanical properties of the coated samples were characterized. Laboratory-simulated wear tests were conducted to evaluate the tribological performance of the coated components. Test results indicate that the wear resistance of AISI 4140 and ASTM A36 steels can be increased 3 and 5 folds, respectively by the application of HDI coatings.

  20. Effect of Porosity on Particle Erosion Wear Behavior of Lab. Scale SICF/SIC Composites

    Science.gov (United States)

    Suh, Min-Soo; Kohyama, Akira

    The use of silicon-based ceramics and composites as combustor liners and turbine vanes provides the potential of improving next-generation turbine engine performance, through lower emissions and higher cycle efficiency, relative to today's use of super alloy hot-section components. As a series of research for FOD resistant, a particle erosion wear test was carried out for continuous Pre-SiC fiber-reinforced SiC matrix composites with a new concept of lab. scale fabrication by LPS process. The result shows that aperture (some form of porosity) between fiber and interface has a deleterious effect on erosion resistance. Aperture along the fiber interfaces consequently causes a severe wear in the form of fiber detachment. Wear rate increase proportional as contents of open porosity increases. For nearly full dense composite materials of about 0.5 % porosity, are about 200 % more wear-resistant than about 5 % porous composites. Grain growth and consolidate condition of matrix which directly affects to FOD resistant are also discussed.

  1. Short communication. Inheritance of yield, yield components and resistance to major diseases in Sesamum indicum L

    Energy Technology Data Exchange (ETDEWEB)

    El-Bramaway, M. A. S.; Shaban, W. I.

    2008-07-01

    Field experiments were conducted over 2005 and 2006 to study the gene action associated with yield and ten yield components, as well as resistance Fusarium wilt, charcoal rot and Alternaria leaf spot, in 6x6 half-diallel sesame progenies (F1). Highly significant differences among the 15 F1s and their six parents were detected with respect to all the investigated traits. A preponderance of non-additive genetic variance was seen for all the studied traits, except for days to maturity and resistance to Alternaria leaf spot. Ten traits showed over dominance. Recessive alleles were predominantly involved in fruiting branches plant-1, capsules plant-1 and single plant yield. The distribution of genes with positive and negative effects were symmetrical or nearly symmetrical with respect to 1000-seed weight, charcoal rot disease resistance, fruiting branches plant-1, capsules plant-1, single plant yield, and oil content. The parents possessed mostly negative genes in dominant form with respect to capsules plant-1, 1000-seed weight, oil content, and resistance to charcoal rot and Alternaria leaf spot; positive genes in recessive form were observed for the rest of the studied traits. Given the gene action observed, bi parental mating or diallel selective mating and heterosis breeding is suggested for the improvement of sesame. (Author) 24 refs.

  2. The influence of Ti, N and Ti + N implantation on phase change, microstructure, growth of metallic compounds and correlated effects in hardness and wear resistance in H13 steel

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Tonghe; Ji Chengzhou; Shen Jinghua; Chen Ju (Inst. of Low Energy Nuclear Physics, Beijing Normal Univ. (China)); Tan Fujin (Dept. of Physics, Jinan Univ., Guangzhou (China)); Gao Yuzun (General Research Inst. for Non-Ferrous Metal, Beijing (China))

    1992-12-01

    The lattice damage, small intermetallic compound (Fe[sub 2]Ti), metallic compound (TiN, Fe[sub 2]N) formation and supersaturated solutions of Ti or Ti + N-ion implanted into steel with various ion doses and energies were measured by TEM and X-ray diffraction formation and growth of the metallic compound has found to depend on ion dose and energy. Change of phases and microstructure were particularly enhanced with high dose and high energy. Metal hardening also increases with increasing ion dose, energy and the amount and size of metallic compounds. Specimens implanted at target temperature ranging from 300degC to 400degC (HT) or implanted at room temperature (RT) and then annealed at temperature ranging from 300 to 500degC, showed significant increase in hardness. The wear resistance of high energy and high dose implanted steel is better than that of low energy and lower dose implantation. The wear rate decreases 2-2.6 times for low temperature implantation, 10.4 times for HT implantation and high energy implantation. The Fe[sub 2]Ti and TiC precipitates, phase and microstructural changes in the implanted layer are responsible for such a drastic reduction in wear. (orig.).

  3. HVOF- and HVAF-Sprayed Cr3C2-NiCr Coatings Deposited from Feedstock Powders of Spherical Morphology: Microstructure Formation and High-Stress Abrasive Wear Resistance Up to 800 °C

    Science.gov (United States)

    Janka, L.; Norpoth, J.; Trache, R.; Thiele, S.; Berger, L.-M.

    2017-10-01

    Chromium carbide-based coatings are commonly applied to protect surfaces against wear at high temperatures. This work discusses the influence of feedstock powder and spray torch selection on the microstructure and high-stress abrasion resistance of thermally sprayed Cr3C2-NiCr coatings. Four commercial feedstock powders with spherical morphology and different microstructures were deposited by different high-velocity spray processes, namely third-generation gas- and liquid-fueled HVOF torches and by the latest generation HVAF torch. The microstructures of the coatings were studied in the as-sprayed state and after various heat treatments. The high-stress abrasion resistance of as-sprayed and heat-treated coatings was tested at room temperature and at 800 °C. The study reveals that the selection of the spray torch mainly affects the room temperature abrasion resistance of the as-sprayed coatings, which is due to differences in the embrittlement of the binder phase generated by carbide dissolution. At elevated temperatures, precipitation and growth of secondary carbides yields a fast equalization of the various coatings microstructures and wear properties.

  4. Development of improved and corrosion-resistant surfaces for fossil power system components

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.; Santella, M.L.; Goodwin, G.M.

    1996-06-01

    The purpose of this task is to develop the corrosion-resistant surfaces on a variety of fossil power system components. The Fe-Al alloys ranging in aluminum from 16 to 36 @ % are of interest. The surfaces of Fe-Al alloys can be produced by weld overlay. However, because of their limited room-temperature ductility, the production of weld wire for these compositions is not commercially feasible. The alloying element dilution during weld overlay also makes depositing exact surface composition rather difficult.

  5. Implant wear mechanisms-basic approach

    Energy Technology Data Exchange (ETDEWEB)

    Bhatt, Himanshu; Goswami, Tarun [Department of Biomedical, Industrial and Human Factors Engineering, Wright State University, Dayton, OH 45435 (United States)

    2008-12-15

    Numerous parameters control the long-term performance of a total hip joint arthroplasty. The articulating motions between the femoral and the acetabular components produce wear debris in a hip implant. Surface roughness, clearance, coefficient of friction and sliding distance are found to be contributing parameters that affect wear rates. Wear produced in a hip implant leads to the loosening of a hip prosthesis and thus failure of the hip implant. Ultra-high-molecular-weight polyethylene (UHMWPE) has been successfully used as an acetabular weight bearing component in the THR applications. Cross-linked UHMWPE was found to improve the lifespan of an artificial hip. A gradient cross-linking of UHMWPE has been observed to be a recent development in implant bearing materials. During in vitro studies, gradient cross-linked UHMWPE showed nearly undetectable wear rates. (topical review)

  6. Development and characterization of fatigue resistant Aramid reinforced aluminium laminates (ARALL) for fatigue Critical aircraft components

    Science.gov (United States)

    Qaiser, M. H.; Umar, S.; Nauman, S.

    2014-06-01

    The structural weight of an aircraft has always been a controlling parameter that governs its fuel efficiency and transport capacity. In pursuit of achieving light-weight aircraft structures, high design stress levels have to be adopted and materials with high specific strength such as Aluminum etc. are to be deployed. However, an extensive spectrum of fatigue load exists at the aircraft wings and other aerodynamic components that may cause initiation and propagation of fatigue cracks and concludes in a catastrophic rupture. Fatigue is therefore the limiting design parameter in such cases and materials with high fatigue resistance are then required. A major improvement in the fatigue behavior was observed by laminating Kevlar fibers with Aluminum using epoxy. ARALL (Aramid Reinforced ALuminum Laminates) is a fatigue resistant hybrid composite that consists of layers of thin high strength aluminum alloy sheets surface bonded with aramid fibers. The intact aramid fibers tie up the fatigue cracks, thus reducing the stress intensity factor at the crack tip as a result of which the fatigue properties of can be enhanced with orders of magnitude as compared to monolithic high strength Aluminum alloy sheets. Significant amount of weight savings can be achieved in fatigue critical components in comparison with the traditional materials used in aircraft.

  7. Obesity is associated with insulin resistance and components of the metabolic syndrome in Lebanese adolescents.

    Science.gov (United States)

    Nasreddine, Lara; Naja, Farah; Tabet, Maya; Habbal, Mohammad-Zuheir; El-Aily, Aida; Haikal, Chrystel; Sidani, Samira; Adra, Nada; Hwalla, Nahla

    2012-03-01

    Prevalence of metabolic syndrome (MS) in obese adolescents has been reported to range between 18-42%, depending on country of origin, thus suggesting an ethnic-based association between obesity and MS. This study aims to investigate the magnitude of the association between obesity, insulin resistance and components of MS among adolescents in Lebanon. The sample included 263 adolescents at 4(th) and 5(th) Tanner stages of puberty (104 obese; 78 overweight; 81 normal weight). Anthropometric, biochemical and blood pressure measurements were performed. Body fat was assessed using dual-energy X-ray absorptiometry. According to International Diabetes Federation criteria, MS was identified in 21.2% of obese, 3.8% of overweight and 1.2% of normal weight subjects. The most common metabolic abnormalities among subjects having MS were elevated waist circumference (96.2%), low HDL (96.2%) and hypertriglyceridemia (73.1%). Insulin resistance was identified in all subjects having MS. Regression analyses showed that percentage body fat, waist circumference and BMI were similar in their ability to predict the MS in this age group. MS was identified in a substantial proportion of Lebanese obese adolescents, thus highlighting the importance of early screening for obesity-associated metabolic abnormalities and of developing successful multi-component interventions addressing adolescent obesity.

  8. Controversy Associated With the Common Component of Most Transgenic Plants – Kanamycin Resistance Marker Gene

    Directory of Open Access Journals (Sweden)

    Srećko Jelenić

    2003-01-01

    Full Text Available Plant genetic engineering is a powerful tool for producing crops resistant to pests, diseases and abiotic stress or crops with improved nutritional value or better quality products. Currently over 70 genetically modified (GM crops have been approved for use in different countries. These cover a wide range of plant species with significant number of different modified traits. However, beside the technology used for their improvement, the common component of most GM crops is the neomycin phosphotransferase II gene (nptII, which confers resistance to the antibiotics kanamycin and neomycin. The nptII gene is present in GM crops as a marker gene to select transformed plant cells during the first steps of the transformation process. The use of antibiotic-resistance genes is subject to controversy and intense debate, because of the likelihood that clinical therapy could be compromised due to inactivation of the oral dose of the antibiotic from consumption of food derived from the transgenic plant, and because of the risk of gene transfer from plants to gut and soil microorganisms or to consumer’s cells. The present article discusses these possibilities in the light of current scientific knowledge.

  9. Effect of microstructure and microhardness on the wear resistance of zirconia-alumina, zirconia-yttria and zirconia-ceria coatings manufactured by atmospheric plasma spraying; fecto de la microestructura y de la microdureza sobre la resistencia al desgaste de recubrimientos elaborados por proyeccion termica por plasma atmosferico a partir de circona-alumina, circona-itria y circona-ceria

    Energy Technology Data Exchange (ETDEWEB)

    Giovanni Gonzalez, A.; Ageorges, H.; Rojas, O.; Lopez, E.; Milena Hurtado, F.; Vargas, F.

    2015-10-01

    The effect of the structure and microhardness on the wear resistance of zirconia-alumina (ATZ), zirconia-yttria (YSZ) and zirconia-ceria (CSZ) coatings manufactured by atmospheric plasma spraying was studied. The microstructure and the fracture on the cross section of the coatings were analyzed using Scanning Electron Microscopy, the phases were identified using X-Ray Diffraction, the microhardness was measured by Vickers indentation and the wear resistance was evaluated by ball on disc test. The results showed that zirconia-alumina coating exhibits the best performance in the wear test. This behavior is closely related to their microstructure and higher microhardness, despite of its significant quantity of the monoclinic zirconia phase, which has lower mechanical properties than tetragonal zirconia phase. Tetragonal zirconia phase was predominant in the zirconia-yttria and zirconia-ceria coatings and despite this behavior; they did not have a good performance in the wear tests. This low wear resistance was mainly influenced by the columnar structure within their lamellae, which caused a greater detachment of particles in the contact surface during the ball-disc tests, increasing its wear. (Author)

  10. Correlation of microstructure with hardness and wear resistance in Cr{sub 3}C{sub 2}/stainless steel surface composites fabricated by high-energy electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Eunsub [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Lee, Sunghak [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)]. E-mail: shlee@postech.ac.kr

    2005-09-25

    Correlation of microstructure with hardness and wear resistance in Cr{sub 3}C{sub 2}/stainless steel surface composites fabricated by high-energy electron beam irradiation was investigated in the present study. Three kinds of powder mixtures, i.e., 50Cr{sub 3}C{sub 2}-50CaF{sub 2}(flux), 100Cr{sub 3}C{sub 2} and 87.5Cr-12.5C (wt.%), were placed on an AISI 316L stainless steel substrate, which was then irradiated with electron beam. In the specimens fabricated without the flux addition, the surface composite layer of 3.5-4.8 mm in thickness was successfully formed without defects by the self-fluxing effect, and contained a large amount (up to 18 vol.%) of Cr{sub 7}C{sub 3} carbides in the austenite matrix. The composite layer fabricated with Cr + C powders having lower melting points than Cr{sub 3}C{sub 2} powders was thicker than that fabricated with Cr{sub 3}C{sub 2} powders because of more effective melting of Cr + C powders during electron beam irradiation. The hardness and wear resistance of the surface composite layer were directly influenced by hard Cr{sub 7}C{sub 3} carbides, and thus were about two times greater than those of the stainless steel substrate.

  11. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gopala N. Krishnan; Ripudaman Malhotra; Jordi Perez; Marc Hornbostel; Kai-Hung Lau; Angel Sanjurjo

    2007-05-31

    Advanced electric power generation systems use a coal gasifier to convert coal to a gas rich in fuels such as H{sub 2} and CO. The gas stream contains impurities such as H{sub 2}S and HCl, which attack metal components of the coal gas train, causing plant downtime and increasing the cost of power generation. Corrosion-resistant coatings would improve plant availability and decrease maintenance costs, thus allowing the environmentally superior integrated-gasification-combined-cycle (IGCC) plants to be more competitive with standard power-generation technologies. Heat-exchangers, particle filters, turbines, and other components in the IGCC system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy will improve is resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. The Fe- and Ni-based high-temperature alloys are susceptible to sulfidation attack unless they are fortified with high levels of Cr, Al, and Si. To impart corrosion resistance, these elements need not be in the bulk of the alloy and need only be present at the surface layers. In this study, the use of corrosion-resistant coatings on low alloy steels was investigated for use as high-temperature components in IGCC systems. The coatings were deposited using SRI's fluidized-bed reactor chemical vapor deposition technique. Diffusion coatings of Cr and Al were deposited by this method on to dense and porous, low alloy stainless steel substrates. Bench-scale exposure tests at 900 C with a simulated coal gas stream containing 1.7% H{sub 2}S showed that the low alloy steels such SS405 and SS409 coated with

  12. Non-Smad TGF-β signaling components are possible biomarkers of tamoxifen resistance

    Science.gov (United States)

    Babyshkina, N.; Zavyalova, M.; Patalyak, S.; Dronova, T.; Slonimskaya, E.; Cherdyntseva, N.

    2017-09-01

    A crosstalk between the estrogen receptor alpha (ERα) and tyrosine kinase receptors contribute to endocrine resistance. We investigated the effect of the four Smad-independent TGF-β signaling components and the distribution pattern of ERα expression on the response to adjuvant tamoxifen treatment in 122 estrogen positive breast cancer patients. We identified a low mRNA expression of TGF-βR1 in tamoxifen resistant group patients (TR) in contrast to tamoxifen sensitive group (TS). Similarly, negative TGF-βR1 expression was significantly higher in TR patients than in TS patients. The expression of TGF-βR1 was strongly correlated with the distribution pattern of ERα expression, level of CD44+/CD24-/low cells and Akt (pS473) expression. The patients with a low mRNA expression of TGF-βR1 as well as with a negative TGF-βR1 expression had an unfavorable prognosis concerning progression-free survival. The expression of TGF-βR1 and the distribution pattern of ERα expression can be considered as additional molecular predictive markers for estrogen positive breast cancer patients treated with adjuvant tamoxifen.

  13. Thujone, a component of medicinal herbs, rescues palmitate-induced insulin resistance in skeletal muscle.

    Science.gov (United States)

    Alkhateeb, Hakam; Bonen, Arend

    2010-09-01

    Thujone is thought to be the main constituent of medicinal herbs that have antidiabetic properties. Therefore, we examined whether thujone ameliorated palmitate-induced insulin resistance in skeletal muscle. Soleus muscles were incubated for Thujone (0.01 mg/ml), in the presence of palmitate, was provided in the last 6 h of incubation. Palmitate oxidation, AMPK/acetyl-CoA carboxylase (ACC) phosphorylation and insulin-stimulated glucose transport, plasmalemmal GLUT4, and AS160 phosphorylation were examined at 0, 6, and 12 h. Palmitate treatment for 12 h reduced fatty acid oxidation (-47%), and insulin-stimulated glucose transport (-71%), GLUT4 translocation (-40%), and AS160 phosphorylation (-26%), but it increased AMPK (+51%) and ACC phosphorylations (+44%). Thujone (6-12 h) fully rescued palmitate oxidation and insulin-stimulated glucose transport, but only partially restored GLUT4 translocation and AS160 phosphorylation, raising the possibility that an increased GLUT4 intrinsic activity may also have contributed to the restoration of glucose transport. Thujone also further increased AMPK phosphorylation but had no further effect on ACC phosphorylation. Inhibition of AMPK phosphorylation with adenine 9-beta-d-arabinofuranoside (Ara) (2.5 mM) or compound C (50 muM) inhibited the thujone-induced improvement in insulin-stimulated glucose transport, GLUT4 translocation, and AS160 phosphorylation. In contrast, the thujone-induced improvement in palmitate oxidation was only slightly inhibited (thujone, a medicinal herb component, rescues palmitate-induced insulin resistance in muscle, the improvement in fatty acid oxidation cannot account for this thujone-mediated effect. Instead, the rescue of palmitate-induced insulin resistance appears to occur via an AMPK-dependent mechanism involving partial restoration of insulin-stimulated GLUT4 translocation.

  14. The development and testing of ceramic components in piston engines. Final report

    Energy Technology Data Exchange (ETDEWEB)

    McEntire, B.J. [Norton Co., Northboro, MA (United States). Advanced Ceramics Div.; Willis, R.W.; Southam, R.E. [TRW, Inc., Cleveland, OH (United States)

    1994-10-01

    Within the past 10--15 years, ceramic hardware has been fabricated and tested in a number of piston engine applications including valves, piston pins, roller followers, tappet shims, and other wear components. It has been shown that, with proper design and installation, ceramics improve performance, fuel economy, and wear and corrosion resistance. These results have been obtained using rig and road tests on both stock and race engines. Selected summaries of these tests are presented in this review paper.

  15. Analysis of Wear Behavior of Graphene OXIDE — Polyamide Gears for Engineering Applications

    Science.gov (United States)

    Rajamani, Geetha; Paulraj, Jawahar; Krishnan, Kanny

    Recent advances in polymer nanocomposites open a wide range of applications in various industrial sectors. Due to their high potential properties, these materials are replacing the usage of metals for many heavier components in automobile industries. In this experimental work, the tribological performance of Graphene oxide (GO) — Polyamide is investigated against pristine polyamide by fabricating gears for the usage in engineering applications. A gear test rig was developed in-house for analysis to study the specific wear rate and temperature gradient at different conditions of load and speeds. The wear resistance of the polyamide gears with the addition of 0.03wt.% of graphene oxide is better than the pristine polyamide gears and the specific wear rate is reduced significantly. The reduced specific wear rate of these polymer nanocomposite gears is attributed to the superior properties of graphene oxide such as High specific surface area, good adhesion properties and enhanced glass transition temperatures. The GO nanocomposite gear seems to be a potential alternative against conventional gears for engineering applications. Finally, the wear mechanisms and the potential of GO-based polyamide nanocomposite gears were proposed tentatively in the development of transmission gears for engineering applications.

  16. Examining the Effects of Quenching Solution, Post-Treatment Heating, and Magnetic Fields upon the Wear Resistance of Wind Turbine Gearbox Bearings

    Science.gov (United States)

    Jakachira, Takunda; Sapp, Whitley; Somers, Hunter; West, Andrea; Watson, Casey; Paulin, Peter

    We explore modifications to the basic cryogenic procedures utilized by 300 Below Inc. to strengthen 52100 steel - the type of steel used to manufacture wind turbine gearbox bearings. We consider the effects of using two different quenching solutions steel samples, additional heating of samples after 300 Below's standard cryogenic treatment, and the application of both AC and permanent magnetic fields of various strengths to samples before and during the standard cryogenic treatment. We report on the wear-test performance of samples that have undergone these additional processes and compare them to the performance of control samples and samples subjected to the standard cryogenic treatment.

  17. Occlusal wear of provisional implant-supported restorations

    NARCIS (Netherlands)

    Santing, Hendrik J.; Kleverlaan, Cornelis J.; Werner, Arie; Feilzer, Albert J.; Raghoebar, Gerry M.; Meijer, Henny J. A.

    BACKGROUND: Implant-supported provisional restorations should be resistant to occlusal wear. PURPOSE: The purpose of this laboratory study was to evaluate three-body wear of three indirect laboratory composite resins, five chair side bis-acryl resin-based materials, and two chair side

  18. Carbon-Based Wear Coatings: Properties and Applications

    Science.gov (United States)

    Miyoshi, Kazuhisa

    2003-01-01

    The technical function of numerous engineering systems - such as vehicles, machines, and instruments - depends on the processes of motion and on the surface systems. Many processes in nature and technology depend on the motion and dynamic behavior of solids, liquids, and gases. Smart surface systems are essential because of the recent technological push toward higher speeds, loads, and operating temperatures; longer life; lighter weight and smaller size (including nanotechnology); and harsh environments in mechanical, mechatronic, and biomechanical systems. If proper attention is not given to surface systems, then vehicles, machines, instruments, and other technical systems could have short lives, consume excessive energy, experience breakdowns, result in liabilities, and fail to accomplish their missions. Surface systems strongly affect our national economy and our lifestyles. At the NASA Glenn Research Center, we believe that proper attention to surface systems, especially in education, research, and application, could lead to economic savings of between 1.3 and 1.6 percent of the gross domestic product. Wear coatings and surface systems continue to experience rapid growth as new coating and surface engineering technologies are discovered, more cost-effective coating and surface engineering solutions are developed, and marketers aggressively pursue, uncover, and exploit new applications for engineered surface systems in cutting tools and wear components. Wear coatings and smart surface systems have been used widely in industrial, consumer, automotive, aerospace, and biomedical applications. This presentation expresses the author's views of and insights into smart surface systems in wear coatings. A revolution is taking place in carbon science and technology. Diamond, an allotrope of carbon, joins graphite, fullerenes, and nanotubes as its major pure carbon structures. It has a unique combination of extreme properties: hardness and abrasion resistance; adhesion

  19. Influencia de los factores microestructurales en la resistencia al desgaste por deslizamiento de las fundiciones nodulares austemperadas. // Influence of the microstructure factors in the sliding wear resistance of austempered cast ductile iron.

    Directory of Open Access Journals (Sweden)

    C. J. Diez Cicero

    2008-09-01

    Full Text Available Entre los materiales metálicos de mayor demanda, el hierro dúctil con grafito esferoidal o nodular ocupa en la actualidaduno de los lugares más importantes entre los hierros fundidos de alta resistencia. Desde hace unos veinticinco años laintroducción del hierro nodular austemperado significó de hecho una revolución en el campo de las aleaciones ferrosas. Enel presente trabajo se realiza un estudio de la influencia del conteo de nódulos de grafito del hierro nodular en el proceso deaustemperado, a partir de las características de las estructuras obtenidas, por la variación de la cantidad de nódulos degrafito y de las variables de tratamiento térmico. Dichas estructuras son sometidas a la acción del desgaste, en este caso aun desgaste por deslizamiento mediante un ensayo típico disco-zapata. Con los resultados obtenidos, se realiza un análisisestadístico de la influencia del conteo de nódulos en dichas propiedades y de las causas de este comportamiento, tomandoen consideración la interrelación del conteo de nódulos con las variables de tratamiento térmico utilizadas en las muestrasensayadas y su incidencia en el mecanismo de desgaste.Palabras claves: Hierro nodular, conteo de nódulos, austemperado, desgaste por deslizamiento.____________________________________________________________________________Abstract:A study about the influence of the graphite nodules quantity and some heat treatment parameters in the characteristic of castductile iron is presented. Experimental investigation of wear resistance by sliding is applied to specimens tested ofaustempered ductile irons using a test machine based in the disc- plate system. Statistical analysis about the influence of thegraphite nodule quantity in the wear resistance properties, so as well as, the causes of this behaviour taking into account thegraphite nodule count and some heat treatment variables is done.Key words: austempered ductile iron, graphite nodules, wear

  20. Structure characterization and wear performance of NiTi thermal sprayed coatings

    Science.gov (United States)

    Cinca, N.; Isalgué, A.; Fernández, J.; Guilemany, J. M.

    2010-08-01

    NiTi shape memory alloy (SMA) has been studied for many years for its shape memory and pseudoelastic properties, as well as its biocompatibility, which make it suitable for many biomedical applications. However, SMA NiTi is also interesting for relevant wear resistance near the transition temperature which, along with its high oxidation and corrosion resistance, suggests its use as a coating to increase the lifetime of some components. Also, whereas bulk material properties have been characterized in respect of the nominal composition, manufacturing methods and thermo-mechanical treatments, NiTi overlays have been investigated much less. Most existent works in this field specifically deal with magnetron sputtering technology for thin films and its use in micro-devices (micro-electro-mechanical systems, MEMS), just some works refer to vacuum plasma spraying (VPS) for thicker coatings. The present paper explores and compares the microstructure and wear-related properties of coatings obtained from atomized NiTi powders, by VPS as well as by atmospheric plasma spraying (APS) and high velocity oxygen fuel (HVOF) techniques. In the present case, the wear behaviour of the NiTi deposits has been studied by rubber-wheel equipment and ball-on-disk tests. The results obtained at room temperature show that the APS-quenched coatings exhibit a preferential dry sliding wear mechanism, while the VPS and HVOF coatings show an abrasive mechanism.

  1. Wear resistance of Fe-Nb-Cr-W, Nb, AISI 1020 and AISI 420 coatings produced by thermal spray wire arc; Resistencia al desgaste de recubrimientos Fe-Nb-Cr-W, Nb, AISI 1020 y AISI 420 producidos por proyeccion termica por arco electrico

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Covaleda, E. A.; Mercado-Veladia, J. L.; Olaya-Florez, J. J.

    2013-07-01

    The commercial materials 140MXC (with iron, tungsten, chrome, niobium), 530AS (AISI 1015 steel) and 560AS (AISI 420 steel) on AISI 4340 steel were deposited using thermal spray with arc. The aim of work was to evaluate the best strategy abrasive wear resistance of the system coating-substrate using the following combinations: (1) homogeneous coatings and (2) coatings depositing simultaneously 140MXC + 530AS and 140MXC + 560AS. The coatings microstructure was characterized using Optical microscopy, Scanning electron microscopy and Laser con focal microscopy. The wear resistance was evaluated through dry sand rubber wheel test (DSRW). We found that the wear resistance depends on the quantity of defects and the mechanical properties like hardness. For example, the softer coatings have the biggest wear rates and the failure mode was characterized by plastic deformation caused by particles indentation, and the other hand the failure mode at the harder materials was grooving. The details and wear mechanism of the coatings produced are described in this investigation. (Author)

  2. FY 1998 annual summary report on research and development of metal-based, heat- and wear-resistant composite materials with controlled mesoscopic diplophase structures (second year); 1998 nendo mesosukopikku fukuso soshiki seigyo tainetsu taimamosei kinzokuki fukugo zairyo no kenkyu kaihatsu seika hokokusho. Daininendo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    This R and D program is aimed at development of highly functional, heat- and wear-resistant composite materials by (1) in-situ method (dissolution and solidification), (2) compositing, based on casting and (3) MA/MM and HIP, and hot pressing, and also aimed at establishment of the techniques for applying these materials to, e.g., transportation machine members, and power generation and steel-making plant members. The heat- and wear-resistant material is characterized by the diplophase structure with a hard phase dispersed in a heat-resistant alloy matrix, where constituent phase type, composition, content, size and distribution are adequately controlled at the mesoscopic level for specific purposes. Fe-Cr-Nb-Mo-Ni-C-based alloys are prepared by the method (1). The Al{sub 2}O{sub 3}-28%SiO{sub 2} composite prepared by the method (2) shows excellent characteristics. Cast iron for the matrix shows excellent controllability, when its P content is increased to 1.8%. The Fe-50%Cr-4.8%C composite prepared by the method (3) is 12 times more resistant to wear than the conventional material. A mixed powder of 2.3% of high-speed steel and TiC or TiN, when MA- and then HIP-treated, shows at least 3 times more resistant to wear than the cast high-speed steel.(NEDO)

  3. Strontium-doped calcium polyphosphate/ultrahigh molecular weight polyethylene composites: A new class of artificial joint components with enhanced biological efficacy to aseptic loosening

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Zhipeng [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu 610041 (China); Huang, Bingxue; Li, Yiwen [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Tian, Meng [Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu 610041 (China); Li, Li [Department of Oncology, the 452 Hospital of Chinese PLA, Chengdu 610021 (China); Yu, Xixun, E-mail: yuxixun@163.com [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China)

    2016-04-01

    To enhance implant stability and prolong the service life of artificial joint component, a new approach was proposed to improve the wear resistance of artificial joint component and endow artificial joint component with the biological efficacy of resistance to aseptic loosening. Strontium calcium polyphosphate (SCPP) were interfused in ultrahigh molecular weight polyethylene (UHMWPE) by a combination of liquid nitrogen ball-milling and flat-panel curing process to prepare the SCPP/UHMWPE composites. The micro-structure, mechanical characterization, tribological characterization and bioactivities of various SCPP/UHMWPE composites were investigated. The results suggested that this method could statistically improve the wear resistance of UHMWPE resulting from a good SCPP particle dispersion. Moreover, it is also observed that the SCPP/UHMWPE composites-wear particles could promote the production of OPG by osteoblasts and decrease the production of RANKL by osteoblasts, and then increase the OPG/RANKL ratio. This indicated that the SCPP/UHMWPE composites had potential efficacy to prevent and treat aseptic loosening. Above all, the SCPP/UHMWPE composites with a suitable SCPP content would be the promising materials for fabricating artificial joint component with ability to resist aseptic loosening. - Highlights: • SCPP/UHMWPE composites could enhance biological efficacy of resistance to aseptic loosening. • SCPP would improve biological efficacy with a few sacrifice of wear resistance. • The results might provide a promising wear-resistant material for fabricating acetabular cup.

  4. Assessment of wear facets produced by the ACTA wear machine

    DEFF Research Database (Denmark)

    Benetti, Ana R; Larsen, Liselotte; Dowling, Adam H

    2016-01-01

    an assessment of the potential of the experimental RBC formulations for clinical usage. CONCLUSION: The 3D technique allowed for the assessment of mean maximum wear depth and mean total volumetric wear which enables tribological analyses of the wear facet and therefore the wear mechanisms operative. Employing...... the 2D profile technique ranks RBC materials in terms of in-vitro wear performance. CLINICAL SIGNIFICANCE: Confidence in the wear volume measurements can only be achieved if the wear facet is analysed with sufficient resolution using a 3D digital measurement technique. However, the employment of 2D...

  5. Análise da microestrutura e da resistência ao desgaste de revestimento duro utilizado pela indústria sucroalcooleira Analysis of microstructure and wear strength of hardfacing used by the sugar and alcohol industry

    Directory of Open Access Journals (Sweden)

    Aldemi Coelho Lima

    2009-06-01

    Full Text Available O setor sucroalcooleiro tem apresentado um expressivo crescimento nos últimos anos no Brasil, entretanto, a manutenção das indústrias apresenta um elevado custo devido à perda de metal dos equipamentos por mecanismos de desgaste. O objetivo deste trabalho é avaliar a resistência ao desgaste abrasivo e a microestrutura de revestimentos duros depositados em camada única. Foram utilizados quatro tipos de consumíveis utilizados na indústria sucroalcooleira: um eletrodo revestido da liga FeCrC de 4,0 mm de diâmetro e três arames tubulares autoprotegidos de 1,6 mm de diâmetro, de ligas FeCrC, FeCrCNb, FeCrCTiMo. O metal de base utilizado foi um aço SAE 1020. As soldagens com os arames tubulares foram efetuadas no modo de transferência por curto-circuito, com mesmos valores de corrente e tensão de soldagem. Para o ensaio de desgaste utilizou-se o abrasômetro Roda de Borracha, segundo a norma ASTM G65-91. Os corpos de prova de desgaste foram retirados da região central das chapas de testes e da mesma região retirou-se dois conjuntos de amostras para análise microestrutural (microscopia ótica. Os resultados dos ensaios com a roda de borracha mostrou que a liga FeCrCNb apresenta maior resistência ao desgaste, seguida do eletrodo revestido e com pior desempenho a liga FeCrCMoTi e a liga FeCrC. A liga FeCrC (tanto para o eletrodo revestido como para o arame tubular apresentou microestrutura formada por carbonetos primários M7C3 distribuídos em uma matriz de menor dureza; a liga contendo Nb apresentou microestrutura similar além da presença de carbonetos NbC; por sua vez, a liga com adição de Ti e Mo apresentou a presença de grandes carbonetos primários de titânio.The Brazilian sugar/alcohol sector presented expressive growth in recent years. However, maintenance cost is high due to metallic losses by wear. This paper studies the application of hardfacing by flux cored arc welding on the wear resistance and microstructure of

  6. Sliding wear studies of microwave clad versus unclad surface of stainless steel 304

    Directory of Open Access Journals (Sweden)

    Akshata M. K.

    2018-01-01

    Full Text Available Small and large scale (gas power plant, hydro power plant, automobile industries are suffering by failure of component. Sometimes, it is also observed that the component which was failed due to these reasons are very much costly and replacement of those also very difficult due to the complex geometry. By using Microwave hybrid heating, WC-12Co based clads were developed on austenitic stainless steel (SS304. Microwave clads were developed by introducing the preplaced, preheated powder for a duration of 15 min to microwave radiation at 2.45GHz frequency and 900 W power in domestic microwave applicator. By using optical microscope and scanning electron microscope (SEM, the developed clads were characterized. By using pin-on-disk, wear performance of the WC-12Co based clads and unclad samples were tested. It is observed that developed clad samples performed superior wear resistance than unclad samples.

  7. Role of two-component systems in the resistance of Staphylococcus aureus to antibacterial agents.

    Science.gov (United States)

    Kawada-Matsuo, Miki; Yoshida, Yuuma; Nakamura, Norifumi; Komatsuzawa, Hitoshi

    2011-01-01

    Two-component systems (TCSs) play important roles in the adaptation of bacteria to environmental changes and the regulation of virulence factor expression. In addition, the association of TCSs with susceptibility to antibacterial agents has been demonstrated in some bacterial species. Staphylococcus aureus, a major human pathogen that can cause serious problems due to nosocomial infections, possesses 16 TCSs. Here we report a TCS, designated BceRS (MW2 gene ID: MW2545-44), which is related to bacitracin susceptibility. We found that BceRS regulates the expression of two transporters that determine susceptibility to bacitracin. One of these, BceAB (MW2543-42), is located downstream of BceRS, while the other, VraDE (MW2620-21), is more distant. With regard to other TCSs, VraRS and Aps/GraRS are reportedly associated with susceptibility to cell wall synthesis inhibitors and cationic antibacterial agents, respectively. Therefore, S. aureus possesses at least three TCSs that are involved in mediating its resistance to antibacterial agents.

  8. EFFECTIVE TOOL WEAR ESTIMATION THROUGH ...

    African Journals Online (AJOL)

    using TiN .coated K20 cemented carbide tool inserts to monitor the tool wear. In the early research, tool wear ... deformation, crack initiation, crack propagation and chipping. Such changes in material behavior will ... the coated carbide experienced rapid tool wear (up to a flank wear land of 0.11 Smm), followed by a slow.

  9. The effect of using components from different manufacturers on the rate of wear and corrosion of the head-stem taper junction of metal-on-metal hip arthroplasties.

    Science.gov (United States)

    Whittaker, R K; Hothi, H S; Meswania, J M; Berber, R; Blunn, G W; Skinner, J A; Hart, A J

    2016-07-01

    Surgeons have commonly used modular femoral heads and stems from different manufacturers, although this is not recommended by orthopaedic companies due to the different manufacturing processes. We compared the rate of corrosion and rate of wear at the trunnion/head taper junction in two groups of retrieved hips; those with mixed manufacturers (MM) and those from the same manufacturer (SM). We identified 151 retrieved hips with large-diameter cobalt-chromium heads; 51 of two designs that had been paired with stems from different manufacturers (MM) and 100 of seven designs paired with stems from the same manufacturer (SM). We determined the severity of corrosion with the Goldberg corrosion score and the volume of material loss at the head/stem junction. We used multivariable statistical analysis to determine if there was a significant difference between the two groups. We found no significant difference in the corrosion scores of the two groups. The median rate of material loss at the head/stem junction for the MM and SM groups were 0.39 mm(3)/year (0.00 to 4.73) and 0.46 mm(3)/year (0.00 to 6.71) respectively; this difference was not significant after controlling for confounding factors (p = 0.06). The use of stems with heads of another manufacturer does not appear to affect the amount of metal lost from the surfaces between these two components at total hip arthroplasty. Other surgical, implant and patient factors should be considered when determining the mechanisms of failure of large diameter metal-on-metal hip arthroplasties. Cite this article: Bone Joint J 2016;98-B:917-24. ©2016 The British Editorial Society of Bone & Joint Surgery.

  10. Surface engineering for enhanced performance against wear

    CERN Document Server

    2013-01-01

    Surface Engineering constitutes a variety of processes and sub processes. Each chapter of this work covers specific processes by experts working in the area. Included for each topic are tribological performances for each process as well as results of recent research. The reader also will benefit from in-depth studies of diffusion coatings, nanocomposite films for wear resistance, surfaces for biotribological applications, thin-film wear, tribology of thermal sprayed coatings, hardfacing, plating for tribology and high energy beam surface modifications. Material scientists as well as engineers working with surface engineering for tribology will be particularly interested in this work.

  11. Development of Advanced Surface Enhancement Technology for Decreasing Wear and Corrosion of Equipment Used for Mineral Processing

    Energy Technology Data Exchange (ETDEWEB)

    Daniel Tao; Craig A. Blue

    2006-07-20

    Equipment wear is a major concern in the mineral processing industry, which dramatically increases the maintenance cost and adversely affects plant operation efficiency. In this research, novel surface treatment technologies, High Density Infrared (HDI) and Laser Surface Engineering (LSE) surface coating processes were developed for the surface enhancement of selected mineral processing equipment. Microstructural and mechanical properties of the coated specimens were characterized. Laboratory-simulated wear tests were conducted to evaluate the tribological performance of the coated components. Test results indicate that the wear resistance of ASTM A36 (raw coal screen section) and can be significantly increased by applying HDI and LSE coating processes. Field testing has been performed using a LSE-treated screen panel and it showed a 2 times improvement of the service life.

  12. Development of Advanced Surface Enhancement Technology for Decreasing Wear and Corrosion of Equipment Used for Mineral Processing

    Energy Technology Data Exchange (ETDEWEB)

    Daniel Tao; Craig A. Blue

    2005-08-01

    Equipment wear is a major concern in the mineral processing industry, which dramatically increases the maintenance cost and adversely affects plant operation efficiency. In this research, a novel surface treatment technology, laser surface engineering (LSE) surface coating process was proposed for the surface enhancement of selected mineral processing equipment. Microstructural and mechanical properties of the coated specimen were characterized. Laboratory-simulated wear tests were conducted to evaluate the tribological performance of the coated components. Test results indicate that the wear resistance of ASTM A36 (raw coal screen section) and AISI 4140 steels can be increased 10 and 25 folds, respectively by the application of LSE process. Initial field testing showed a 2 times improvement of the service life of a raw coal screen panel.

  13. Development of Advanced Surface Enhancement Technology for Decreasing Wear and Corrosion of Equipment Used for Mineral Processing

    Energy Technology Data Exchange (ETDEWEB)

    Daniel Tao; R. Honaker; B. K. Parekh

    2007-09-20

    Equipment wear is a major concern in the mineral processing industry, which dramatically increases the maintenance cost and adversely affects plant operation efficiency. In this research, novel surface treatment technologies, High Density Infrared (HDI) and Laser Surface Engineering (LSE) surface coating processes were developed for the surface enhancement of selected mineral and coal processing equipment. Microstructural and mechanical properties of the coated specimens were characterized. Laboratory-simulated wear tests were conducted to evaluate the tribological performance of the coated components. Test results indicate that the wear resistance of ASTM A36 (raw coal screen section) and can be significantly increased by applying HDI and LSE coating processes. Field testing has been performed using a LSE-treated screen panel and it showed a significant improvement of the service life.

  14. Identification and QTL mapping of whitefly resistance components in Solanum galapagense

    NARCIS (Netherlands)

    Firdaus, S.; Heusden, van A.W.; Hidayati, N.; Supena, E.D.J.; Mumm, R.; Vos, de R.C.H.; Visser, R.G.F.; Vosman, B.

    2013-01-01

    Solanum galapagense is closely related to the cultivated tomato and can show a very good resistance towards whitefly. A segregating population resulting from a cross between the cultivated tomato and a whitefly resistant S. galapagense was created and used for mapping whitefly resistance and related

  15. Qualification of Life Extension Schemes for Engine Components (Homologation des Programmes de Prolongation du cycle de vie des Organes Moteur)

    Science.gov (United States)

    1999-03-01

    electronic components * polycarbonate substrates (e.g. opthalmic lenses) "* tribological parts (wear resistance, low friction) 0 IR components "* protective...in the paper illustrates that short term life © Crown Copyright 1998/DERA increases of up to 20% are sometimes at the price of less Published with

  16. Effects of Load and Speed on Wear Rate of Abrasive Wear for 2014 Al Alloy

    Science.gov (United States)

    Odabas, D.

    2018-01-01

    In this paper, the effects of the normal load and sliding speed on wear rate of two-body abrasive wear for 2014 Al Alloy were investigated in detail. In order to understand the variation in wear behaviour with load and speed, wear tests were carried out at a sliding distance of 11 m, a speed of 0.36 m/s, a duration of 30 s and loads in the range 3-11 N using 220 grit abrasive paper, and at a speed range 0.09-0.90 m/s, a load of 5 N and an average sliding distance of 11 m using abrasive papers of 150 grit size under dry friction conditions. Before the wear tests, solution treatment of the 2014 Al alloy was carried out at temperatures of 505 and 520 °C for 1 h in a muffle furnace and then quenched in cold water at 15 °C. Later, the ageing treatment was carried out at 185 °C for 8 h in the furnace. Generally, wear rate due to time increased linearly and linear wear resistance decreased with increasing loads. However, the wear rate was directly proportional to the load up to a critical load of 7 N. After this load, the slope of the curves decreased because the excessive deformation of the worn surface and the instability of the abrasive grains began to increase. When the load on an abrasive grain reaches a critical value, the groove width is about 0.17 of the abrasive grain diameter, and the abrasive grains begin to fail. The wear rate due to time increased slightly as the sliding speed increased in the range 0.09-0.90 m/s. The reason for this is that changes arising from strain rate and friction heating are expected with increasing sliding speeds.

  17. Investigation on wear characteristic of biopolymer gear

    Science.gov (United States)

    Ghazali, Wafiuddin Bin Md; Daing Idris, Daing Mohamad Nafiz Bin; Sofian, Azizul Helmi Bin; Basrawi, Mohamad Firdaus bin; Khalil Ibrahim, Thamir

    2017-10-01

    Polymer is widely used in many mechanical components such as gear. With the world going to a more green and sustainable environment, polymers which are bio based are being recognized as a replacement for conventional polymers based on fossil fuel. The use of biopolymer in mechanical components especially gear have not been fully explored yet. This research focuses on biopolymer for spur gear and whether the conventional method to investigate wear characteristic is applicable. The spur gears are produced by injection moulding and tested on several speeds using a custom test equipment. The wear formation such as tooth fracture, tooth deformation, debris and weight loss was observed on the biopolymer spur gear. It was noted that the biopolymer gear wear mechanism was similar with other type of polymer spur gears. It also undergoes stages of wear which are; running in, linear and rapid. It can be said that the wear mechanism of biopolymer spur gear is comparable to fossil fuel based polymer spur gear, thus it can be considered to replace polymer gears in suitable applications.

  18. Effect of wearing a swimsuit on hydrodynamic drag of swimmer

    Directory of Open Access Journals (Sweden)

    Daniel Almeida Marinho

    2012-12-01

    Full Text Available The purpose of this study was to analyse the effect of wearing a swimsuit on swimmer's passive drag. A computational fluid dynamics analysis was carried out to determine the hydrodynamic drag of a female swimmer's model (i wearing a standard swimsuit; (ii wearing a last generation swimsuit and; (iii with no swimsuit, wearing light underwear. The three-dimensional surface geometry of a female swimmer's model with different swimsuit/underwear was acquired through standard commercial laser scanner. Passive drag force and drag coefficient were computed with the swimmer in a prone position. Higher hydrodynamic drag values were determined when the swimmer was with no swimsuit in comparison with the situation when the swimmer was wearing a swimsuit. The last generation swimsuit presented lower hydrodynamic drag values, although very similar to standard swimsuit. In conclusion, wearing a swimsuit could positively influence the swimmer's hydrodynamics, especially reducing the pressure drag component.

  19. Influence of Multiple Bionic Unit Coupling on Sliding Wear of Laser-Processed Gray Cast Iron

    Science.gov (United States)

    Zhang, Haifeng; Zhang, Peng; Sui, Qi; Zhao, Kai; Zhou, Hong; Ren, Luquan

    2017-04-01

    In this study, in effort to improve the sliding wear resistance of gray cast iron under wet lubrication conditions, specimens with different bionic units were manufactured and modified according to bionic theory. Inspired by the structure and appearance of biological wear-resistant skin, two kinds of bionic units were processed by laser on the specimen surfaces. We investigated the wear resistance properties of the samples via indentation method and then observed the wear surface morphology of specimens and the stress distributions. The results indicated that coupling the bionic units enhanced the wear resistance of the cast iron considerably compared to the other samples. We also determined the mechanism of wear resistance improvement according to the results.

  20. Wear Resistance of Piston Sleeve Made of Layered Material Structure: MMC A356R, Anti-Abrasion Layer and FGM Interface

    Directory of Open Access Journals (Sweden)

    Hernik Szymon

    2016-09-01

    Full Text Available The aim of this paper is the numerical analysis of the one of main part of car engine – piston sleeve. The first example is for piston sleeve made of metal matrix composite (MMC A356R. The second improved material structure is layered. Both of them are comparison to the classical structure of piston sleeve made of Cr-Ni stainless steel. The layered material structure contains the anti-abrasion layer at the inner surface of piston sleeve, where the contact and friction is highest, FGM (functionally graded material interface and the layer of virgin material on the outer surface made of A356R. The complex thermo-elastic model with Archard's condition as a wear law is proposed. The piston sleeve is modelling as a thin walled cylindrical axisymmetric shell. The coupled between the formulation of thermo-elasticity of cylindrical axisymmetric shell and the Archard’s law with functionally changes of local hardness is proposed.

  1. High Temperature Dry Sliding Friction and Wear Performance of Laser Cladding WC/Ni Composite Coating

    Directory of Open Access Journals (Sweden)

    YANG Jiao-xi

    2016-06-01

    Full Text Available Two different types of agglomerate and angular WC/Ni matrix composite coatings were deposited by laser cladding. The high temperature wear resistance of these composite coatings was tested with a ring-on-disc MMG-10 apparatus. The morphologies of the worn surfaces were observed using a scanning electron microscopy (SEM equipped with an energy dispersive spectroscopy (EDS for elemental composition. The results show that the high temperature wear resistance of the laser clad WC/Ni-based composite coatings is improved significantly with WC mass fraction increasing. The 60% agglomerate WC/Ni composite coating has optimal high temperature wear resistance. High temperature wear mechanism of 60% WC/Ni composite coating is from abrasive wear of low temperature into composite function of the oxidation wear and abrasive wear.

  2. Multi technical analysis of wear mechanisms in axial piston pumps

    Science.gov (United States)

    Schuhler, G.; Jourani, A.; Bouvier, S.; Perrochat, J.-M.

    2017-05-01

    Axial piston pumps convert a motor rotation motion into hydraulic or pneumatic power. Their compactness and efficiency of approximately 0.9 make them suitable for actuation applications especially in aeronautics. However, they suffer a limited life due to the wear of their components. In the literature, studies of axial piston pumps deal with contact between its different elements under lubrication conditions. Nevertheless, they are more focused on analytic or numerical approaches. This study consists in an experimental analysis of worn pump components to highlight and understand wear mechanisms. Piston shoes are central components in the axial piston pump since they are involved in three tribological contacts. These three contacts are thereby studied: piston shoes/swashplate, piston shoes/pistons and piston shoes/shoes hold down plate (SHDP). To perform this analysis, helicopter hydraulic pumps after different operating times have been studied. The wear damage mechanisms and wear debris are analysed using SEM observations. 3D surface roughness measurements are then used to characterize worn surfaces. The observations reveal that in the contact between shoes and swashplate, the main wear mechanism is three-body abrasive wear due to coarse carbides removal. Between shoes and pistons, wear occurs in a less severe way and is mainly due to the debris generated in the first contact and conveyed by the lubricating fluid. In the third contact, the debris are also the prime cause of the abrasive wear and the generation of deep craters in the piston shoes.

  3. Wear Protection of AJ62 Mg Engine Blocks using Plasma Electrolytic Oxidation Process

    Science.gov (United States)

    Zhang, Peng

    2011-12-01

    In order to reduce the fuel consumption and pollution, automotive companies are developing magnesium-intensive components. However, due to the low wear resistance of the magnesium (Mg) alloys, Mg cylinder bores are vulnerable to the sliding wear attack. In this thesis, two approaches were used to protect the cylinder bores, made of a new developed Mg engine alloy AJ62 (MgA16Mn0.34Sr2). The first one was to use a Plasma Electrolytic Oxidation (PEO) process to produce oxide coatings on the Mg bores. The wear properties of the PEO coatings were evaluated by sliding wear tests under the boundary lubrication condition at the room and elevated temperatures. It was found that due to the substrate softening and the vaporization loss of the lubricant, the tribological properties of the PEO coatings were deteriorated at the elevated temperature. In order to optimize the PEO process, a statistical method (Response surface method) was used to analyze the effects of the 4 main PEO process parameters with 2 levels for each and their interactions on the tribological properties of the PEO coatings at the room and elevated temperatures, individually. A cylinder liner made of an economical metal-matrix composite (MMC) was another approach to improve the wear resistance of the Mg cylinder bore. In this thesis, an A1383/SiO2 MMC was designed to replace the expensive Alusil alloy used in the BMW Mg/Al composite engine to build the cylinder liner. To further increase the wear resistance of the MMC, PEO process was also used to form an oxide coating on the MMC. The effects of the SiO 2 content and coating thickness on the tribological properties of the MMC were studied. To evaluate the wear properties of the optimal PEO coated Mg coupons and the MMC with the oxide coatings, Alusil and cast iron, currently used on the cylinder bores of the commercial aluminum engines, were used as reference materials. The optimal PEO coated Mg coupons and the oxidized MMC showed their advantages over the

  4. Identification of genes required for nonhost resistance to Xanthomonas oryzae pv. oryzae reveals novel signaling components.

    Directory of Open Access Journals (Sweden)

    Wen Li

    Full Text Available BACKGROUND: Nonhost resistance is a generalized, durable, broad-spectrum resistance exhibited by plant species to a wide variety of microbial pathogens. Although nonhost resistance is an attractive breeding strategy, the molecular basis of this form of resistance remains unclear for many plant-microbe pathosystems, including interactions with the bacterial pathogen of rice, Xanthomonas oryzae pv. oryzae (Xoo. METHODS AND FINDINGS: Virus-induced gene silencing (VIGS and an assay to detect the hypersensitive response (HR were used to screen for genes required for nonhost resistance to Xoo in N. benthamiana. When infiltrated with Xoo strain YN-1, N. benthamiana plants exhibited a strong necrosis within 24 h and produced a large amount of H(2O(2 in the infiltrated area. Expression of HR- and defense-related genes was induced, whereas bacterial numbers dramatically decreased during necrosis. VIGS of 45 ACE (Avr/Cf-elicited genes revealed identified seven genes required for nonhost resistance to Xoo in N. benthamiana. The seven genes encoded a calreticulin protein (ACE35, an ERF transcriptional factor (ACE43, a novel Solanaceous protein (ACE80, a hydrolase (ACE117, a peroxidase (ACE175 and two proteins with unknown function (ACE95 and ACE112. The results indicate that oxidative burst and calcium-dependent signaling pathways play an important role in nonhost resistance to Xoo. VIGS analysis further revealed that ACE35, ACE80, ACE95 and ACE175, but not the other three ACE genes, interfered with the Cf-4/Avr4-dependent HR. CONCLUSIONS/SIGNIFICANCE: N. benthamiana plants inoculated with Xoo respond by rapidly eliciting an HR and nonhost resistance. The oxidative burst and other signaling pathways are pivotal in Xoo-N. benthamiana nonhost resistance, and genes involved in this response partially overlap with those involved in Cf/Avr4-dependent HR. The seven genes required for N. benthamiana-mediated resistance to Xoo provide a basis for further dissecting

  5. Insulin resistance and its association with the components of the metabolic syndrome among obese children and adolescents

    Directory of Open Access Journals (Sweden)

    Mass-Díaz Eliezer

    2010-06-01

    Full Text Available Abstract Background Insulin resistance is the primary metabolic disorder associated with obesity; yet little is known about its role as a determinant of the metabolic syndrome in obese children. The aim of this study is to assess the association between the degree of insulin resistance and the different components of the metabolic syndrome among obese children and adolescents. Methods An analytical, cross-sectional and population-based study was performed in forty-four public primary schools in Campeche City, Mexico. A total of 466 obese children and adolescents between 11-13 years of age were recruited. Fasting glucose and insulin concentrations, high density lipoprotein cholesterol, triglycerides, waist circumference, systolic and diastolic blood pressures were measured; insulin resistance and metabolic syndrome were also evaluated. Results Out of the total population studied, 69% presented low values of high density lipoprotein cholesterol, 49% suffered from abdominal obesity, 29% had hypertriglyceridemia, 8% presented high systolic and 13% high diastolic blood pressure, 4% showed impaired fasting glucose, 51% presented insulin resistance and 20% metabolic syndrome. In spite of being obese, 13% of the investigated population did not present any metabolic disorder. For each one of the components of the metabolic syndrome, when insulin resistance increased so did odds ratios as cardiometabolic risk factors. Conclusions Regardless of age and gender an increased degree of insulin resistance is associated with a higher prevalence of disorders in each of the components of the metabolic syndrome and with a heightened risk of suffering metabolic syndrome among obese children and adolescents.

  6. Mitigation of wear damage by laser surface alloying technique

    CSIR Research Space (South Africa)

    Adebiyi, ID

    2016-04-01

    Full Text Available , and alloys having these specific properties are usually very expensive and their use drastically increases components and production costs. Moreover, the economic implications of wear, in form of detrimental effects – and waste, are severe. This includes...

  7. Couple of biomimetic surfaces with different morphologies for remanufacturing nonuniform wear rail surface

    Science.gov (United States)

    Sui, Qi; Zhou, Hong; Yang, Lin; Zhang, Haifeng; Feng, Li; Zhang, Peng

    2018-02-01

    In this work, biomimetic laser treatment was performed on repairing and remanufacturing the nonuniform worn rail surface. The wearing depth distribution of three work regions of a failure rail surface was discussed, and different thickness hardening layers with different microstructure, microhardness and wear resistances were detected from the worm surfaces. Varying wear resistances of the surfaces with different biomimetic morphologies were obtained by biomimetic laser treatments, and the corresponding effect on the lubrication sliding wear of treated and untreated surfaces were studied for comparative study. In addition, the relationship between wear resistance and the spacing of units was also provided, which can lay the important theoretical foundation for avoiding the wear resistance of the serious worn surface is less than that of the slight worn surface in the future practical applications.

  8. The Devil Wears Prada

    African Journals Online (AJOL)

    Adele

    The film is based on the book. The Devil Wears Prada written by Lauren Weisberger, ... image and power driven industry that is haute couture and fashion today. Although Andrea's experience is the main ... creations not fit even for Halloween, designer and brand name jewellery and other fashion accessories. Anything from ...

  9. Comparative wear mapping techniques

    DEFF Research Database (Denmark)

    Alcock, J.; Sørensen, Ole Toft; Jensen, S.

    1996-01-01

    Pin surfaces were analysed by laser profilometry. Two roughness parameters, R(a) and the fractal dimension, were investigated as a first step towards methods of quantitative wear mechanism mapping. Both parameters were analysed for their relationship to the severity and prevalence of a mechanism....

  10. Wear Properties of Nuclear Graphite IG-110 at Elevated Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Dunkun; Kim, Jaehoon; Kim, Yeonwook [Chungnam National University, Daejeon (Korea, Republic of)

    2014-05-15

    The high temperature gas-cooled reactor (HTR-10) is designed to produce electricity and hydrogen. Graphite is used as reflector, support structures, and a moderator in reactor core; it has good resistance to neutron and is a suitable material at high temperatures. Friction is generated in the graphite structures for the core reflector, support structures, and moderator because of vibration from the HTR-10 fuel cycle flow. In this study, the wear characteristics of the isotropic graphite IG-110 used in HTR-10 were evaluated. The reciprocating wear test was carried out for graphite against graphite. The effects of changes in the contact load and sliding speeds at room temperature and 400℃ on the coefficient of friction and specific wear rate were evaluated. The wear behavior of graphite IG-110 was evaluated based on the wear surfaces.

  11. Oxidation Resistant CMC Materials Technology for Lightweight and Environmentally Durable Propulsion Components Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Foster-Miller will demonstrate a novel processing method to develop environmentally resistant C/SiC composites for turbomachinery. The need to reduce the weight,...

  12. Oxidation Resistant CMC Materials Technology for Lightweight and Environmentally Durable Propulsion Components Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Surmet will demonstrate a novel processing method to develop environmentally resistant C/SiC composites for turbomachinery. The need to reduce the weight, size, and...

  13. Influence of heat treatment on the wear life of hydraulic fracturing tools

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Chao; Liu, Yonghong; Wang, Hanxiang; Qin, Jie; Shen, Yang; Zhang, Shihong [China University of Petroleum, Qingdao (China)

    2017-02-15

    Wear phenomenon has caused severe damage or failure of fracturing tools in oil and gas industry. In this paper, influence of heat treatment on the mechanical properties and wear resistance of fracturing tool made of lamellar graphite grey cast iron were investigated. The surface composition and microstructure were characterized by X-ray diffraction (XRD) and metallographic microscope. Sliding wear tests were performed to study the tribological behavior. Tests results showed that wear rates of treated specimens decreased by 33 %. Besides, worn morphology and wear debris were analyzed using Scanning electron microscope (SEM) and Energy dispersive Xray spectra (EDS). Wear failure mechanisms of specimens were identified. Furthermore, on-site experiment results indicated that wear loss of treated samples decreased by 37.5 %. The wear life of hydraulic fracturing tools can be improved obviously by the heat treatment.

  14. Prestressing Shock Resistant Mechanical Components and Mechanisms Made from Hard, Superelastic Materials

    Science.gov (United States)

    DellaCorte, Christopher (Inventor)

    2014-01-01

    A method and an apparatus confer full superelastic properties to the active surface of a mechanical component constructed of a superelastic material prior to service. A compressive load is applied to the active surface of the mechanical component followed by removing the compressive load from the active surface whereby substantially all load strain is recoverable after applying and removing of subsequent compressive loads.

  15. The germinlike protein GLP4 exhibits superoxide dismutase activity and is an important component of quantitative resistance in wheat and barley

    DEFF Research Database (Denmark)

    Christensen, Anders Bentsen; Thordal-Christensen, Hans; Zimmermann, Grit

    2004-01-01

    overexpression of TaGLP4 and HvGLP4 enhanced resistance against B. graminis in wheat and barley, whereas transient silencing by RNA interference reduced basal resistance in both cereals. The effect of GLP4 overexpression or silencing was strongly influenced by the genotype of the plant. The data suggest...... that members of GLP subfamily 4 are components of quantitative resistance in both barley and wheat, acting together with other, as yet unknown, plant components....

  16. Thermal resistance of Listeria monocytogenes Scott A in ultrafiltered milk as related to the effect of different milk components.

    Science.gov (United States)

    Szlachta, Kinga; Keller, Susanne E; Shazer, Arlette; Chirtel, Stuart

    2010-11-01

    Pasteurization parameters for grade A milk are well established and set by regulation. However, as solids levels increase, an increased amount of heat is required to destroy any pathogens present. This effect is not well characterized. In this work, the effect of increased dairy solids levels on the thermal resistance of Listeria monocytogenes was examined through the use of ultrafiltered (UF) milk, reconstituted milk powder, and the milk components lactose and caseinate. From the results obtained, lactose and caseinate did not appear to affect thermal resistance. In addition, the level of milk fat, up to 10% of the total solids in UF whole milk, did not result in statistically significant changes to thermal resistance when compared with UF skim milk. Reconstituted skim milk powder at 27% total solids (D⁶²-value = 1.16 ± 0.2 [SD] min, z = 5.7) did result in increased thermal resistance, as compared with reconstituted skim milk powder at 17.5% (D⁶²-value = 0.86 ± 0.02 min, z = 5.57) and UF whole milk at 27% total solids (D⁶²-value = 0.66 ± 0.07 min, z = 5.16). However, that increase appeared to be due to the increase in salt levels, not to increases in caseinate, fat, or lactose. Consequently, total solids, as a single measure, could not be used to predict increased thermal resistance of L. monocytogenes in concentrated milk.

  17. Towards low-friction and wear-resistant plasma sintering dies via plasma surface co-alloying CM247 nickel alloy with V/Ag and N

    Directory of Open Access Journals (Sweden)

    Zhang Zhenxue

    2015-01-01

    Full Text Available Nickel based superalloys have good oxidation and creep resistance and hence they can function under high mechanical stress and high temperatures. However, their undesirable tribological behaviour is the major technical barrier to the challenging high-temperature, lubricant-free plasma sintering tool application. In this study, nickel based CM247 superalloy surfaces were co-alloyed using innovative active screen plasma technology with both interstitial element (e.g. N and substitutional alloying elements (e.g. V and Ag to provide a synergy effect to enhance its tribological properties. The tribological behaviour of the plasma co-alloyed CM247 superalloy surfaces were fully evaluated using reciprocal and pin-on-disc tribometers at temperatures from room temperature to 600 ∘C. The experimental results demonstrate that the co-alloyed surface with N, Ag and V can effectively lower the friction coefficient, which is expected to help demoulding during lubricant-free plasma sintering.

  18. Plant height and internode length as components of lodging resistance in barley

    Directory of Open Access Journals (Sweden)

    Madić Milomirka

    2016-01-01

    Full Text Available With the total acreage of 50 million ha and an annual production of about 140 million tonnes, barley ranks high in world cereal production. Selection of new cultivars is mostly associated with a particular ideotype designed by the breeder in line with the targets and goals specified. Although grain yield is an ongoing objective in creating new cultivars, breeding work on barley is further expanded to include other traits, primarily grain quality and lodging resistance. Lodging resistance is largely determined by the genetic background of certain stem properties (length, strength and flexibility and root system development i.e. structure. The degree of lodging resistance in barley is significantly affected by the morphological traits of aboveground parts (stem length, strength and flexibility; stem wall thickness; length, number and weight of internodes; spike size and spike weight. The new cultivars of winter malting barley currently used by producers are generally characterized by very good lodging resistance and an average plant height of 90 to 100 cm. Breeding spring malting barley has resulted in an optimal height (about 80 cm. Further changes should focus on increasing stem thickness and changing the anatomical structure to ensure sufficient stem strength.

  19. Avaliação da resistência ao desgaste de aluminas nanométricas produzidas a partir da decomposição térmica de acetato de alumínio liofilizado Evaluation of wear resistance of nanometric aluminas produced by thermal decomposition of lyophilized aluminum acetate

    Directory of Open Access Journals (Sweden)

    E. Fagury Neto

    2007-12-01

    Full Text Available Ensaios de resistência ao desgaste, na modalidade pino-contra-disco com pares deslizantes, foram realizados em pinos confeccionados a partir de pós de alumina proveniente do processo de decomposição térmica de acetato de alumínio liofilizado. Pós de alumina referentes às fases alfa-Al2O3 e gama-Al2O3, com e sem aditivos de sinterização (MgO e La2O3, foram usados para confeccionar pinos de desgaste. Pinos feitos também a partir de alumina comercial (A1000 SG foram analisados e os resultados foram comparados. Os ensaios foram feitos de acordo com norma ASTM e mostraram que os pinos confeccionados a partir de alfa-Al2O3 têm elevada resistência ao desgaste, comprovada pelos ensaios de perda de massa e microscopia eletrônica. Os pinos de gama-Al2O3 tiveram desempenho intermediário e os pinos de A1000 SG mostraram resultados menos expressivos.Wear resistance tests, using the pin-on-disk test method with sliding pairs, were carried out on pins produced from alumina powders prepared by thermal decomposition of lyophilized aluminum acetate. Alumina powders of alpha-Al2O3 and gamma-Al2O3 phases, with and without sintering additives (MgO and La2O3, were used to produce wear pins. In addition, pins made of commercial alumina (A1000 SG were tested and the results compared. The tests, carried out according to the ASTM standard, indicated that the pins made with alpha-Al2O3 powder showed high wear resistance, a finding corroborated by mass loss tests and scanning electron microscopy. The gamma-Al2O3 pins showed an intermediary performance while the A1000 SG pins showed less interesting results.

  20. Microstructure and wear behaviour of FeAl-based composites ...

    Indian Academy of Sciences (India)

    resistance of FeAl-based alloys is found to be significantly improved on addition of Ti/Zr. This is attributed to the high hardness of alloy carbides. The lower ... exhibit superior wear resistance due to higher hardness of carbides [6,12,17,18]. However ..... Also, most of the literature is on composites fabricated through PM route ...

  1. The Role of CzcRS Two-Component Systems in the Heavy Metal Resistance of Pseudomonas putida X4

    Directory of Open Access Journals (Sweden)

    Pulin Liu

    2015-07-01

    Full Text Available The role of different czcRS genes in metal resistance and the cross-link between czcRS and czcCBA in Pseudomonas putida X4 were studied to advance understanding of the mechanisms by which P. putida copes with metal stress. Similar to P. putida KT2440, two complete czcRS1 and czcRS2 two-component systems, as well as a czcR3 without the corresponding sensing component were amplified in P. putida X4. The histidine kinase genes czcS1 and czcS2 were inactivated and fused to lacZ by homologous recombination. The lacZ fusion assay revealed that Cd2+ and Zn2+ caused a decrease in the transcription of czcRS1, whereas Cd2+ treatment enhanced the transcription of czcRS2. The mutation of different czcRSs showed that all czcRSs are necessary to facilitate full metal resistance in P. putida X4. A putative gene just downstream of czcR3 is related to metal ion resistance, and its transcription was activated by Zn2+. Data from quantitative real-time polymerase chain reaction (qRT-PCR strongly suggested that czcRSs regulate the expression of czcCBA, and a cross-link exists between different czcRSs.

  2. Suppressing Nanoscale Wear by Graphene/Graphene Interfacial Contact Architecture: A Molecular Dynamics Study.

    Science.gov (United States)

    Xu, Qiang; Li, Xin; Zhang, Jie; Hu, Yuanzhong; Wang, Hui; Ma, TianBao

    2017-11-07

    Nanoscale wear is one of the key factors hindering the performance and lifetime of micro- and nanosystems, such as the scanning tip wear in atomic force microscopy (AFM), the head-disk interface in magnetic storage system, and the moving components in micro- or nanoelectromechanical systems (MEMS/NEMS). Here, we propose to construct the graphene/graphene interfacial architecture to suppress the nanoscale wear. Molecular dynamics simulations show that the atomic roughness of the sliding surfaces with either stepped or amorphous structure can lead to strong inhomogeneity of the local contact pressure distribution. By coating graphene on both sides of the frictional surfaces, the local contact pressure fluctuations due to the atomic roughness are suppressed. Moreover, this trend is more evident with the increasing layer number of the graphene coating. Furthermore, the nanoscratching simulation suggests that the rupture of graphene is driven by the inhomogeneous pressure distribution-induced lateral atomic interlocking between the rough tip and substrate and the consequent in-plane lattice deformation and C-C bond breaking during sliding. By coating graphene on the rough amorphous carbon tip, the critical normal load for wear failure of graphene is significantly increased, due to the weakening effect of the atomic interlocking by improving the contact conditions with atomically smooth graphene/graphene sliding interface. This investigation reveals a strategy for reducing nanowear by suppressing the local contact pressure fluctuations via graphene/graphene sliding interface architecture, which provides a theoretical guidance for designing wear-resistant coatings for the longevity of AFM probes and MEMS/NEMS systems.

  3. On the Estimation of Permeabilities and Draw Resistances of Cigarette Components

    Directory of Open Access Journals (Sweden)

    Eitzinger B

    2014-12-01

    Full Text Available The goal of this study is to investigate whether the permeability of the tipping/plugwrap system, the permeability of the cigarette paper and the draw resistances of the filter and tobacco rod can be calculated from measurements of the degree of filter ventilation and of the open and closed draw resistance. This issue is investigated for a linear and a non-linear model of the flow in unlit cigarettes. At first it is proven that there exist experimental conditions to which the cigarette can be exposed such that the problem has at least a unique solution. The problem is then solved by least-squares optimisation for a linear and a non-linear model of the air flow in unlit cigarettes with various noise levels on the output quantities. The error sensitivity of the optimisation problem is estimated by calculation of the condition number.

  4. Modelling changes in terrain resistance as a component of landform evolution in unstable hill country

    Science.gov (United States)

    Crozier, M. J.; Preston, N. J.

    Accurate modelling of landform evolution in unstable terrain requires some means of determining the frequency and magnitude of landslide occurrence. In many areas, this can be achieved with reference to the potency of the triggering regime and the susceptibility of the terrain. Terrain susceptibility is controlled by inherent geomechanical resistance and topographic conditions which filter the effect of the triggering agent. For a given terrain, susceptibility can be conveniently represented by establishing the triggering threshold required for the occurrence of landslides. Problems are identified in use of thresholds developed from historical and contemporary measurements of landslide activity to predict or postdict landslide activity. Even if all other external controlling factors remain constant, there appear to be event-related temporal shifts in terrain resistance which change the level of the triggering threshold and the occurrence of landslides over time. Mechanisms responsible for this change are proposed and the results of field investigation into geomechanical limiting equilibrium conditions are produced to demonstrate the effects of these mechanisms and the changes in resistance they produce. A conceptual model is presented to place event-related changes in susceptibility into the context of a major phase of landslide-induced soil erosion which has affected New Zealand hill country since European deforestation.

  5. The influence of laser line hardening of carbon steel AISI 1045 on the lubricated wear against steel AISI 52100

    NARCIS (Netherlands)

    Visscher, H.; de Rooij, Matthias B.; Vroegop, P.H.; Schipper, Dirk J.

    1995-01-01

    To diminish wear in tribological systems it is not always necessary to provide the entire surface with a wear resistant layer. Depending on the application it is sufficient to harden locally the load carrying areas which are subjected to wear. Such areas can be treated properly by a laser, either

  6. Investigation of piston ring – cylinder liner dry wear using a block-on-ring test rig

    DEFF Research Database (Denmark)

    Bihlet, Uffe; Klit, Peder; Felter, Christian L.

    Characterization of the wear of piston rings and cylinder liner is an important aspect of large two stroke diesel engine design. Two major wear mechanisms exist; corrosive wear and mechanical wear. This paper deals with the most aggressive form of the latter, which is known as scuffing. Different...... material combinations for piston rings and cylinder liners are examined using a block-on-ring test rig. An accelerated wear test run without lubricant is used. Results show that the morphology of cast iron is an important parameter affecting the wear resistance of the material. It is also demonstrated...

  7. Wear-Out Sensitivity Analysis Project Abstract

    Science.gov (United States)

    Harris, Adam

    2015-01-01

    During the course of the Summer 2015 internship session, I worked in the Reliability and Maintainability group of the ISS Safety and Mission Assurance department. My project was a statistical analysis of how sensitive ORU's (Orbital Replacement Units) are to a reliability parameter called the wear-out characteristic. The intended goal of this was to determine a worst case scenario of how many spares would be needed if multiple systems started exhibiting wear-out characteristics simultaneously. The goal was also to determine which parts would be most likely to do so. In order to do this, my duties were to take historical data of operational times and failure times of these ORU's and use them to build predictive models of failure using probability distribution functions, mainly the Weibull distribution. Then, I ran Monte Carlo Simulations to see how an entire population of these components would perform. From here, my final duty was to vary the wear-out characteristic from the intrinsic value, to extremely high wear-out values and determine how much the probability of sufficiency of the population would shift. This was done for around 30 different ORU populations on board the ISS.

  8. Evaluating the accuracy of wear formulae for acetabular cup liners.

    Science.gov (United States)

    Wu, James Shih-Shyn; Hsu, Shu-Ling; Chen, Jian-Horng

    2010-02-01

    This study proposes two methods for exploring the wear volume of a worn liner. The first method is a numerical method, in which SolidWorks software is used to create models of the worn out regions of liners at various wear directions and depths. The second method is an experimental one, in which a machining center is used to mill polyoxymethylene to manufacture worn and unworn liner models, then the volumes of the models are measured. The results show that the SolidWorks software is a good tool for presenting the wear pattern and volume of a worn liner. The formula provided by Ilchmann is the most suitable for computing liner volume loss, but is not accurate enough. This study suggests that a more accurate wear formula is required. This is crucial for accurate evaluation of the performance of hip components implanted in patients, as well as for designing new hip components.

  9. Investigation on the Tribological Behavior and Wear Mechanism of Five Different Veneering Porcelains

    Science.gov (United States)

    Min, Jie; Zhang, Qianqian; Qiu, Xiaoli; Zhu, Minhao; Yu, Haiyang; Gao, Shanshan

    2015-01-01

    Objectives The primary aim of this research was to investigate the wear behavior and wear mechanism of five different veneering porcelains. Methods Five kinds of veneering porcelains were selected in this research. The surface microhardness of all the samples was measured with a microhardness tester. Wear tests were performed on a ball-on-flat PLINT fretting wear machine, with lubrication of artificial saliva at 37°C. The friction coefficients were recorded by the testing system. The microstructure features, wear volume, and damage morphologies were recorded and analyzed with a confocal laser scanning microscope and a scanning electron microscope. The wear mechanism was then elucidated. Results The friction coefficients of the five veneering porcelains differ significantly. No significant correlation between hardness and wear volume was found for these veneering porcelains. Under lubrication of artificial saliva, the porcelain with higher leucite crystal content exhibited greater wear resistance. Additionally, leucite crystal size and distribution in glass matrix influenced wear behavior. The wear mechanisms for these porcelains were similar: abrasive wear dominates the early stage, whereas delamination was the main damage mode at the later stage. Furthermore, delamination was more prominent for porcelains with larger crystal sizes. Significance Wear compatibility between porcelain and natural teeth is important for dental restorative materials. Investigation on crystal content, size, and distribution in glass matrix can provide insight for the selection of dental porcelains in clinical settings. PMID:26368532

  10. Investigation on the Tribological Behavior and Wear Mechanism of Five Different Veneering Porcelains.

    Directory of Open Access Journals (Sweden)

    Jie Min

    Full Text Available The primary aim of this research was to investigate the wear behavior and wear mechanism of five different veneering porcelains.Five kinds of veneering porcelains were selected in this research. The surface microhardness of all the samples was measured with a microhardness tester. Wear tests were performed on a ball-on-flat PLINT fretting wear machine, with lubrication of artificial saliva at 37°C. The friction coefficients were recorded by the testing system. The microstructure features, wear volume, and damage morphologies were recorded and analyzed with a confocal laser scanning microscope and a scanning electron microscope. The wear mechanism was then elucidated.The friction coefficients of the five veneering porcelains differ significantly. No significant correlation between hardness and wear volume was found for these veneering porcelains. Under lubrication of artificial saliva, the porcelain with higher leucite crystal content exhibited greater wear resistance. Additionally, leucite crystal size and distribution in glass matrix influenced wear behavior. The wear mechanisms for these porcelains were similar: abrasive wear dominates the early stage, whereas delamination was the main damage mode at the later stage. Furthermore, delamination was more prominent for porcelains with larger crystal sizes.Wear compatibility between porcelain and natural teeth is important for dental restorative materials. Investigation on crystal content, size, and distribution in glass matrix can provide insight for the selection of dental porcelains in clinical settings.

  11. Investigation on the Tribological Behavior and Wear Mechanism of Five Different Veneering Porcelains.

    Science.gov (United States)

    Min, Jie; Zhang, Qianqian; Qiu, Xiaoli; Zhu, Minhao; Yu, Haiyang; Gao, Shanshan

    2015-01-01

    The primary aim of this research was to investigate the wear behavior and wear mechanism of five different veneering porcelains. Five kinds of veneering porcelains were selected in this research. The surface microhardness of all the samples was measured with a microhardness tester. Wear tests were performed on a ball-on-flat PLINT fretting wear machine, with lubrication of artificial saliva at 37°C. The friction coefficients were recorded by the testing system. The microstructure features, wear volume, and damage morphologies were recorded and analyzed with a confocal laser scanning microscope and a scanning electron microscope. The wear mechanism was then elucidated. The friction coefficients of the five veneering porcelains differ significantly. No significant correlation between hardness and wear volume was found for these veneering porcelains. Under lubrication of artificial saliva, the porcelain with higher leucite crystal content exhibited greater wear resistance. Additionally, leucite crystal size and distribution in glass matrix influenced wear behavior. The wear mechanisms for these porcelains were similar: abrasive wear dominates the early stage, whereas delamination was the main damage mode at the later stage. Furthermore, delamination was more prominent for porcelains with larger crystal sizes. Wear compatibility between porcelain and natural teeth is important for dental restorative materials. Investigation on crystal content, size, and distribution in glass matrix can provide insight for the selection of dental porcelains in clinical settings.

  12. Evolution of multidrug resistance during Staphylococcus aureus infection involves mutation of the essential two component regulator WalKR.

    Directory of Open Access Journals (Sweden)

    Benjamin P Howden

    2011-11-01

    Full Text Available Antimicrobial resistance in Staphylococcus aureus is a major public health threat, compounded by emergence of strains with resistance to vancomycin and daptomycin, both last line antimicrobials. Here we have performed high throughput DNA sequencing and comparative genomics for five clinical pairs of vancomycin-susceptible (VSSA and vancomycin-intermediate ST239 S. aureus (VISA; each pair isolated before and after vancomycin treatment failure. These comparisons revealed a frequent pattern of mutation among the VISA strains within the essential walKR two-component regulatory locus involved in control of cell wall metabolism. We then conducted bi-directional allelic exchange experiments in our clinical VSSA and VISA strains and showed that single nucleotide substitutions within either walK or walR lead to co-resistance to vancomycin and daptomycin, and caused the typical cell wall thickening observed in resistant clinical isolates. Ion Torrent genome sequencing confirmed no additional regulatory mutations had been introduced into either the walR or walK VISA mutants during the allelic exchange process. However, two potential compensatory mutations were detected within putative transport genes for the walK mutant. The minimal genetic changes in either walK or walR also attenuated virulence, reduced biofilm formation, and led to consistent transcriptional changes that suggest an important role for this regulator in control of central metabolism. This study highlights the dramatic impacts of single mutations that arise during persistent S. aureus infections and demonstrates the role played by walKR to increase drug resistance, control metabolism and alter the virulence potential of this pathogen.

  13. Evolution of multidrug resistance during Staphylococcus aureus infection involves mutation of the essential two component regulator WalKR.

    Science.gov (United States)

    Howden, Benjamin P; McEvoy, Christopher R E; Allen, David L; Chua, Kyra; Gao, Wei; Harrison, Paul F; Bell, Jan; Coombs, Geoffrey; Bennett-Wood, Vicki; Porter, Jessica L; Robins-Browne, Roy; Davies, John K; Seemann, Torsten; Stinear, Timothy P

    2011-11-01

    Antimicrobial resistance in Staphylococcus aureus is a major public health threat, compounded by emergence of strains with resistance to vancomycin and daptomycin, both last line antimicrobials. Here we have performed high throughput DNA sequencing and comparative genomics for five clinical pairs of vancomycin-susceptible (VSSA) and vancomycin-intermediate ST239 S. aureus (VISA); each pair isolated before and after vancomycin treatment failure. These comparisons revealed a frequent pattern of mutation among the VISA strains within the essential walKR two-component regulatory locus involved in control of cell wall metabolism. We then conducted bi-directional allelic exchange experiments in our clinical VSSA and VISA strains and showed that single nucleotide substitutions within either walK or walR lead to co-resistance to vancomycin and daptomycin, and caused the typical cell wall thickening observed in resistant clinical isolates. Ion Torrent genome sequencing confirmed no additional regulatory mutations had been introduced into either the walR or walK VISA mutants during the allelic exchange process. However, two potential compensatory mutations were detected within putative transport genes for the walK mutant. The minimal genetic changes in either walK or walR also attenuated virulence, reduced biofilm formation, and led to consistent transcriptional changes that suggest an important role for this regulator in control of central metabolism. This study highlights the dramatic impacts of single mutations that arise during persistent S. aureus infections and demonstrates the role played by walKR to increase drug resistance, control metabolism and alter the virulence potential of this pathogen.

  14. RESISTANCE OF COATED ELECTRODES SUITABLE FOR RENOVATION OF TILLAGE TOOLS

    Directory of Open Access Journals (Sweden)

    Martin Kotus

    2013-12-01

    Full Text Available This article deals with the abrasive wear resistance of additional materials. The resistance of individual materials was figured out by determining a proportional wear resistance on a grinding fabric. Results of the experiment confirmed an increase in welds abrasive wear resistance. Chosen coated electrodes are suitable for the renovation of tillage tools of agricultural machines.

  15. Identifying the components in eggshell membrane responsible for reducing the heat resistance of bacterial pathogens.

    Science.gov (United States)

    Ahlborn, Gene; Sheldon, Brian W

    2006-04-01

    The biological activity (D-value determination) of eggshell membrane (ESM) was examined to determine the membrane components and mechanisms responsible for antibacterial activity. Biological and enzymatic activities (i.e., beta-N-acetylglucosaminidase [beta-NAGase], lysozyme, and ovotransferrin) of ESM denatured with trypsin, lipases, or heat were compared with those of untreated ESM. Trypsin-treated ESM lost all biological activity (D-values at 54 degrees C were 5.12 and 5.38 min for immobilized and solubilized trypsin, respectively) but showed no significant loss of enzymatic activities. Treatments with porcine lipase and a lipase cocktail did not impact biological or enzymatic activities. Heat denaturation of ESM (at 80 and 100 degrees C for 15 min) resulted in significant decreases in biological activity (D-values of 3.99 and 4.43 min, respectively) and loss of beta-NAGase activity. Lysozyme and ovotransferrin activities remained but were significantly reduced. Purified ESM and hen egg white components (i.e., beta-NAGase, lysozyme, and ovotransferrin) were added to Salmonella Typhimurium suspensions (in 0.1% peptone water) at varying concentrations to evaluate their biological activity. D-values at 54 degrees C were 4.50 and 3.68 min for treatment with lysozyme or beta-NAGase alone, respectively, and 2.44 min for ovotransferrin but 1.47 min for a combination of all three components (similar to values for ESM). Exposure of Salmonella Typhimurium cells to a mixture of ovotransferrin, lysozyme, and beta-NAGase or ESM resulted in significant increases in extracellular concentrations of Ca2+, Mg2+, and K+. Transmission electron microscopic examination of Salmonella Typhimurium cells treated with a combination of ovotransferrin, lysozyme, and beta-NAGase revealed membrane disruption and cell lysis. The findings of this study demonstrate that ovotransferrin, lysozyme, and beta-NAGase are the primary components responsible for ESM antibacterial activity. The

  16. Wear and flexural strength comparisons of alumina/feldspar resin infiltrated dental composites.

    Science.gov (United States)

    Le Roux, A R; Lachman, N; Walker, M; Botha, T

    2008-11-01

    Incorporating a feldspar chemical bond between alumina filler particles is expected to increase the wear-resistant and flexural strength properties. An investigation was carried out to evaluate the influence of the feldspar chemical bonding between alumina filler particles on wear and flexural strength of experimental alumina/feldspar dental composites. It was hypothesized that wear resistance and flexural strength would be significantly increased with increased feldspar mass. Alumina was chemically sintered and bonded with 30% and 60% feldspar mass, silanized and infiltrated with UDMA resin to prepare the dental restorative composite material. Higher wear-resistant characteristics resulted with increased feldspar mass of up to 60% (p 0.05). Feldspar chemical bonding between the alumina particles may improve on the wear-resistance and flexural strength of alumina/feldspar composites.

  17. Friction and wear behaviour of self lubricating bearing liners

    Science.gov (United States)

    Gay, Russell

    The thesis describes a numerical model for evaluating the variation of friction and wear of a self lubricating bearing liner over its useful wear life. Self-lubricating bearings have been in widespread use since the mid-1950s, particularly in the aerospace industry where they have the advantage of being low maintenance components. They are commonly used in relatively low speed, reciprocating applications such as control surface actuators, and usually consist of a spherical bearing with the inner and outer elements separated by a composite textile resin-bonded liner. A finite element model has been developed to predict the local stiffness of a particular liner at different states of wear. Results obtained using the model were used to predict the overall friction coefficient as it evolves due to wear, which is a novel approach. Experimental testing was performed on a bespoke flat-on-flat wear test rig with a reciprocating motion to validate the results of the friction model.. These tests were carried out on a commercially-available bearing liner, predominantly at a high contact pressure and an average sliding speed of 0.2 ms-1. Good agreement between predicted and experimentally measured wear was obtained when appropriate coefficients of friction were used in the friction model, and when the reciprocating sliding distance was above a critical value. A numerical wear model was also developed to predict the trend of backlash development in real bearing geometries using a novel approach. Results from the wear model were validated against full-scale bearing tests carried out elsewhere by the sponsoring company. Good agreement was obtained between the model predictions and the experimental results for the first 80% of the bearing wear life, and explanations for the discrepancy during the last 20% of the wear life have been proposed..

  18. Wear of polymers and composites

    CERN Document Server

    Abdelbary, Ahmed

    2015-01-01

    In the field of tribology, the wear behaviour of polymers and composite materials is considered a highly non-linear phenomenon. Wear of Polymers and Composites introduces fundamentals of polymers and composites tribology. The book suggests a new approach to explore the effect of applied load and surface defects on the fatigue wear behaviour of polymers, using a new tribometer and thorough experiments. It discusses effects of surface cracks, under different static and cyclic loading parameters on wear, and presents an intelligent algorithm, in the form of a neural network, to map the relations

  19. Friction and wear calculation methods

    CERN Document Server

    Kragelsky, I V; Kombalov, V S

    1981-01-01

    Friction and Wear: Calculation Methods provides an introduction to the main theories of a new branch of mechanics known as """"contact interaction of solids in relative motion."""" This branch is closely bound up with other sciences, especially physics and chemistry. The book analyzes the nature of friction and wear, and some theoretical relationships that link the characteristics of the processes and the properties of the contacting bodies essential for practical application of the theories in calculating friction forces and wear values. The effect of the environment on friction and wear is a

  20. Mechanical modelling of tooth wear.

    Science.gov (United States)

    Karme, Aleksis; Rannikko, Janina; Kallonen, Aki; Clauss, Marcus; Fortelius, Mikael

    2016-07-01

    Different diets wear teeth in different ways and generate distinguishable wear and microwear patterns that have long been the basis of palaeodiet reconstructions. Little experimental research has been performed to study them together. Here, we show that an artificial mechanical masticator, a chewing machine, occluding real horse teeth in continuous simulated chewing (of 100 000 chewing cycles) is capable of replicating microscopic wear features and gross wear on teeth that resemble wear in specimens collected from nature. Simulating pure attrition (chewing without food) and four plant material diets of different abrasives content (at n = 5 tooth pairs per group), we detected differences in microscopic wear features by stereomicroscopy of the chewing surface in the number and quality of pits and scratches that were not always as expected. Using computed tomography scanning in one tooth per diet, absolute wear was quantified as the mean height change after the simulated chewing. Absolute wear increased with diet abrasiveness, originating from phytoliths and grit. In combination, our findings highlight that differences in actual dental tissue loss can occur at similar microwear patterns, cautioning against a direct transformation of microwear results into predictions about diet or tooth wear rate. © 2016 The Author(s).

  1. Nutrition, insulin resistance and dysfunctional adipose tissue determine the different components of metabolic syndrome

    Science.gov (United States)

    Paniagua, Juan Antonio

    2016-01-01

    Obesity is an excessive accumulation of body fat that may be harmful to health. Today, obesity is a major public health problem, affecting in greater or lesser proportion all demographic groups. Obesity is estimated by body mass index (BMI) in a clinical setting, but BMI reports neither body composition nor the location of excess body fat. Deaths from cardiovascular diseases, cancer and diabetes accounted for approximately 65% of all deaths, and adiposity and mainly abdominal adiposity are associated with all these disorders. Adipose tissue could expand to inflexibility levels. Then, adiposity is associated with a state of low-grade chronic inflammation, with increased tumor necrosis factor-α and interleukin-6 release, which interfere with adipose cell differentiation, and the action pattern of adiponectin and leptin until the adipose tissue begins to be dysfunctional. In this state the subject presents insulin resistance and hyperinsulinemia, probably the first step of a dysfunctional metabolic system. Subsequent to central obesity, insulin resistance, hyperglycemia, hypertriglyceridemia, hypoalphalipoproteinemia, hypertension and fatty liver are grouped in the so-called metabolic syndrome (MetS). In subjects with MetS an energy balance is critical to maintain a healthy body weight, mainly limiting the intake of high energy density foods (fat). However, high-carbohydrate rich (CHO) diets increase postprandial peaks of insulin and glucose. Triglyceride-rich lipoproteins are also increased, which interferes with reverse cholesterol transport lowering high-density lipoprotein cholesterol. In addition, CHO-rich diets could move fat from peripheral to central deposits and reduce adiponectin activity in peripheral adipose tissue. All these are improved with monounsaturated fatty acid-rich diets. Lastly, increased portions of ω-3 and ω-6 fatty acids also decrease triglyceride levels, and complement the healthy diet that is recommended in patients with MetS. PMID

  2. Development of Novel Pre-alloyed PM Steels for Optimization of Machinability and Fatigue Resistance of PM Components

    Science.gov (United States)

    Mardan, Milad; Blais, Carl

    2016-03-01

    It is well known that a large proportion of ferrous PM components require secondary machining operations for dimensional conformance or for producing geometrical features that cannot be generated during die compaction. Nevertheless, the machining behavior of PM parts is generally characterized as being "difficult" due to the presence of residual porosity that lowers thermal conductivity and induces interrupted cutting. Several admixed additives such as MnS and BN-h can be used to improve the machining behavior of PM steels. Nevertheless, their negative effect on mechanical properties, especially fatigue resistance, makes their utilization uninteresting for the fabrication of high-performance PM steel components. This article summarizes the work carried out to develop a novel PM steel that was especially engineered to form machinability enhancing precipitates. This new material is pre-alloyed with tin (Sn) in order to form Cu-Sn (Cu(α)) precipitates during transient liquid phase sintering. The newly developed material presents machinability improvement of 165% compared to reference material used in the PM industry as well as increases in toughness and fatigue resistance of 100% and 13%, respectively.

  3. Effect of a Deep Cryogenic Treatment on Wear and Microstructure of a 6101 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Volker Franco Steier

    2016-01-01

    Full Text Available The aim of this work is to evaluate the effect of a deep cryogenic treatment (DCT on the wear behavior and on the microstructure of an aluminum alloy. In order to compare the level of improvement on the wear resistance provided by the DCT with a more traditional technique, a test matrix which included DCT, CrN coated specimens, and combinations of both modification methods was conducted. The wear behavior was investigated using microabrasive wear tests. The cryogenic treated specimens proved to have similar low wear rates as the specimens coated with CrN. The most distinct improvement was reached with a combination of both techniques. In the case of the DCT, the performed microstructural analysis identified the generation of additional GP-zones as the reason for the improved wear resistance.

  4. Wear properties of nanosilica filled epoxy polymers and FRP composites

    Directory of Open Access Journals (Sweden)

    A. Jumahat

    2015-09-01

    Full Text Available This paper is aimed to determine the wear properties of nanosilica filled epoxy polymers and FRP composites. Woven fiberglass has been deployed as the reinforcement material. The fibers were mixed with three different percentages of nanosilica-modified epoxy resin, i.e: 5wt%; 13wt%; 25wt%, in order to fabricate the desired samples of FRP composites. The effect of nanosilica on wear properties was evaluated using dry sliding wear and slurry tests. The results show that increasing the amount of nanosilica content has reduced the amount of accumulated mass loss. It was found that the FRP laminates with 25wt% of nanosilica have the highest wear resistance. The nanosilica filled fiber reinforced polymer composites have a high potential in tribological application such as ball bearing housing and snow sleds.

  5. Analysis of polymerization time on abrasive wear of dental resins

    Directory of Open Access Journals (Sweden)

    Eduardo Carlos Bianchi

    2010-03-01

    Full Text Available An evaluation was made of the abrasive wear of six composite thermofixed dental resins subjected to different polymerization times. The method of evaluation was based on sharpness measurements to quantify the abrasive wear resistance of the resins. To this end, a test bench was built, consisting of a rotating porcelain cylinder that wears out a resin-coated cylinder placed above it, thus causing vertical displacement of the contact as the wear progresses. The values of vertical displacement, i.e., the input variables, were read and recorded by means of a computer program to obtain the sharpness values. These data indicated that the resins displayed different behaviors as a function of the polymerization times applied, reinforcing the importance of using a practical and rapid method of analysis in order to ensure that the behavior of new materials is fully understood before they are launched on the market.

  6. Pure mechanical wear loss measurement in corrosive wear

    Indian Academy of Sciences (India)

    Unknown

    Abstract. The method for the measurement of the pure mechanical wear loss for 321 stainless steel, 1045 steel and pure iron in the study of the synergy between corrosion and wear was studied. The methods studied included the measurement in distilled water, by cathodic protection and by adding inhibitor KI, and all were.

  7. Wear characteristics in a two-body wear test.

    Science.gov (United States)

    Wassell, R W; McCabe, J F; Walls, A W

    1994-07-01

    A previous report compared spherical steatite (ceramic enamel substitute) abraders with those of natural enamel in a two-body wear test. The wear rates and coefficients of friction of the two abraders against various composites and an amalgam were well correlated although the wear rates were slightly higher with steatite. This report investigates the characteristics of the worn abrader and specimen surfaces. Scanning electron microscopy and laser profilometry were used. Similar wear characteristics were found for the two types of abraders. Adhesive wear was evident for the amalgam, Dispersalloy (Johnson & Johnson), and the heat/pressure-cured microfill composite, Isosit (Ivoclar-Vivadent). Abrasion was seen with the hybrid composite, Occlusin (ICI), and, to a lesser extent, the microfill composite, Heliomolar (Ivoclar-Vivadent). The appearance of the worn small particle hybrid composite, Brilliant Dentin (Coltène), suggested that fatigue and delamination were involved. Laser profilometry showed that the hybrid composites caused much greater wear to the abraders than either the microfill composites or amalgam. The Ra values of the worn abraders and specimens were similar, suggesting conformal contact between them and endorsing the well controlled conditions of the wear test. The results of this and other publications suggest that steatite can be used as an alternative to enamel in performing two-body wear tests on dental composites. This should help significantly in materials evaluation and development.

  8. Pure mechanical wear loss measurement in corrosive wear

    Indian Academy of Sciences (India)

    The method for the measurement of the pure mechanical wear loss for 321 stainless steel, 1045 steel and pure iron in the study of the synergy between corrosion and wear was studied. The methods studied included the measurement in distilled water, by cathodic protection and by adding inhibitor KI, and all were ...

  9. Mutations in durum wheat SBEII genes conferring increased amylose and resistant starch affect grain yield components, semolina and pasta quality and fermentation responses in rats

    Science.gov (United States)

    Increased amylose in wheat (Triticum spp.) starch is associated with increased resistant starch, a fermentable dietary fiber. Fermentation of resistant starch in the large intestine produces short-chain fatty acids that provide human health benefits. Since wheat foods are an important component of t...

  10. Evaluation and silicon nitride internal combustion engine components. Final report, Phase I

    Energy Technology Data Exchange (ETDEWEB)

    Voldrich, W. [Allied-Signal Aerospace Co., Torrance, CA (United States). Garrett Ceramic Components Div.

    1992-04-01

    The feasibility of silicon nitride (Si{sub 3}N{sub 4}) use in internal combustion engines was studied by testing three different components for wear resistance and lower reciprocating mass. The information obtained from these preliminary spin rig and engine tests indicates several design changes are necessary to survive high-stress engine applications. The three silicon nitride components tested were valve spring retainers, tappet rollers, and fuel pump push rod ends. Garrett Ceramic Components` gas-pressure sinterable Si{sub 3}N{sub 4} (GS-44) was used to fabricate the above components. Components were final machined from densified blanks that had been green formed by isostatic pressing of GS-44 granules. Spin rig testing of the valve spring retainers indicated that these Si{sub 3}N{sub 4} components could survive at high RPM levels (9,500) when teamed with silicon nitride valves and lower spring tension than standard titanium components. Silicon nitride tappet rollers showed no wear on roller O.D. or I.D. surfaces, steel axles and lifters; however, due to the uncrowned design of these particular rollers the cam lobes indicated wear after spin rig testing. Fuel pump push rod ends were successful at reducing wear on the cam lobe and rod end when tested on spin rigs and in real-world race applications.

  11. Wear Assessment of Conical Pick used in Coal Cutting Operation

    Science.gov (United States)

    Dewangan, Saurabh; Chattopadhyaya, Somnath; Hloch, Sergej

    2015-09-01

    Conical pick is a widely used tool for cutting coal in mines. It has a cemented carbide tip inserted in a steel body. Cemented carbide has been in use for many years for coal/rock cutting because it has the optimum combination of hardness, toughness and resistance against abrasive wear. As coal/rock is a heterogeneous substance, the cutting tool has to undergo various obstructions at the time of excavation that cause the tool to wear out. The cracks and fractures developing in the cemented carbide limit the life of the tool. For a long time, different wear mechanisms have been studied to develop improved grades of cemented carbide with high wear resistance properties. The research is still continuing. Moreover, due to the highly unpredictable nature of coal/rock, it is not easy to understand the wear mechanisms. In the present work, an attempt has been made to understand the wear mechanisms in four conical picks, which were used in a continuous miner machine for underground mining of coal. The wearing pattern of the conical pick indicates damage in its cemented carbide tip as well as the steel body. The worn out parts of the tools have been critically examined using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) point analysis. Mainly four types of wear mechanisms, namely, coal/rock intermixing, plastic deformation, rock channel formation and crushing and cracking, have been detected. The presence of coal/rock material and their respective concentrations in the selected area of worn out surface were observed using the spectra generated by EDX analysis.

  12. Influence of Growth Stage and Leaf Age on Expression of the Components of Partial Resistance of Faba Bean to Botrytis fabae Sard.

    Directory of Open Access Journals (Sweden)

    A. Bouhassan

    2004-12-01

    Full Text Available In detached leaf tests on faba bean (Vicia faba L., genotypes partially resistant and susceptible to Botrytis fabae were examined. Expression of four components of partial resistance to a virulent isolate of B. fabae differed depending on the plant age and the leaf age of the genotypes. The incubation period of resistant genotypes at the podding stage was longer than that of susceptible genotypes at the same stage. The area under disease progress curve (AUDPC of the lesion size increased from the seedling to the flowering stage but declined at the podding stage in all genotypes. Differences between resistant and susceptible genotypes for lesion size were significant except on old leaves from plants at the podding stage. The latent period decreased, and spore production increased with increasing growth and leaf age but there was significant interaction with the genotype. These last two components of partial resistance were more clearly expressed at all growth stages on FRY167 (highly resistant but were expressed only at the seedling and podding stages on FRY7 (resistant. The resistant line BPL710 was not significantly different from the susceptible genotypes for the latent period at any growth stage, and for spore production at the seedling and flowering stages. Leaf age affected all genotypes, but with a significant interaction between leaf age and growth stage. Components of partial resistance were more strongly expressed on young leaves from plants at the seedling or flowering stage.

  13. ROTARY FUEL INJECTION PUMP WEAR TESTING USING A 30 %/ 70% ATJ/F-24 FUEL BLEND

    Science.gov (United States)

    2017-09-30

    moderate wear. 4. The additional 5% ATJ in the test blend may have improved injection pump wear resistance due to a slight viscosity improvement...Reaction D1094 Volume Change of Aqueous Layer mL 1.0 1.0 Interface Condition rating 1B 1B Separation -- 2 2 MSEP D3948 rating 62 67 Fuel... changed at 250-hour intervals. The laboratory scale wear performed on the test fuels was the Ball on Cylinder Lubricity Evaluator procedure

  14. Stiction, friction, and wear reduction in silicon microelectromechanical systems

    Science.gov (United States)

    Mantiziba, Fadziso Mabel

    Current reliability issues in silicon based microelectromechanical systems (MEMS) pose a challenge in the advancement of this pervasive technology. Silicon Microsystems are encumbered with adhesion induced catastrophic failures (stiction) during the final fabrication step where a wet chemical etch release is often conducted to produce functional, suspended microstructures. Irreversible adhesion of active device layer components to the substrate can drastically reduce yields of fully functional devices. Potential in-use problems of a tribological nature also limit the reliability and device lifetimes of these microstructures, particularly where intermittent or continuous contacting of surfaces occurs during a device's normal operation. Understanding the fundamental tribological properties such as friction coefficients and wear mechanisms that occur in the normal operation of these devices is a necessity in providing potential long term solutions to such reliability issues. A unique, simple, yet inexpensive solution to release related adhesion failures that utilizes a temporary physical barrier during the final rinsing stage of a typical silicon wet etch release process is presented. This temporary barrier is accomplished using polystyrene microspheres that prevent contact between the substrate and the components of the suspended device layer during drying. The microspheres are subsequently removed using a plasma etching process. Improvement of yields of stiction-free, functional devices >90% in comparison to rinse liquids have been demonstated using this process. To address tribological reliability issues for silicon MEMS, friction testing devices are utilized to measure the friction coefficients of silicon. Thin ceramic coatings of oxides of aluminum, zirconium, or titanium are applied to the silicon MEMS devices using the atomic layer deposition technique and tested for comparison to non-coated silicon surfaces. Testing conducted under controlled humidity shows

  15. Effect of a muscular resistance training program to improve physical fitness components in older females

    Directory of Open Access Journals (Sweden)

    José Antonio Gonzalezjurado

    2011-06-01

    Full Text Available The aim of this study was to estimate the effect of resistance training program in the fitness of untrained older women. Fourteen women in Chile (65,86 ± 6.55 kg, 1.55 ± 0.06 m, 67.71 ± 5.31 years old underwent a program of strength training for 6 weeks, performing Back Test (BT , Leg Press (PS, Bench Press (BP and Knee Extension (ER at 3 sessions per week, recording measurements before and after the period of training on maximal dynamic strength (FDM estimated indirectly by the mass displaced in a maximal repetitions test on those exercises and maximal oxygen consumption (VO2máx estimated by the UKK test. The results show significant differences between the pre-and post-test values (mean ± SD of estimated VO2max (11.02 ± 7.26 and 15.57 ± 5.17 ml kg-1 min-1, P <0.05 and FDM estimated the pre-and post-tests (mean ± SD in LS: 43.09 ± 6.19 and 51.27 ± 9.07 N (p <0.01, PB: 21,12 ± 5.77 and 29.08 ± 7.47 kg (p <0.001, ER: 18.60 ± 5.07 and 21.99 ± 5.21 kg (p <0.05 and PS: 18,60 ± 5.07 and 21.99 ± 5.21 kg (p <0.05. We conclude that the proposed training program improves the FDM in this sample of older adults.

  16. Tyre and road wear prediction

    NARCIS (Netherlands)

    Lupker, H.A.

    2003-01-01

    Both tyre wear and road polishing are complex phenomenon, which are obviously strongly related; the energy that polishes the road is the energy that wears the tyre. The both depend non-linearly on numerous parameters, like materials used, vehicle and road usage, environmental conditions (i.e.

  17. Switch wear leveling

    Science.gov (United States)

    Wu, Hunter; Sealy, Kylee; Gilchrist, Aaron

    2015-09-01

    An apparatus for switch wear leveling includes a switching module that controls switching for two or more pairs of switches in a switching power converter. The switching module controls switches based on a duty cycle control technique and closes and opens each switch in a switching sequence. The pairs of switches connect to a positive and negative terminal of a DC voltage source. For a first switching sequence a first switch of a pair of switches has a higher switching power loss than a second switch of the pair of switches. The apparatus includes a switch rotation module that changes the switching sequence of the two or more pairs of switches from the first switching sequence to a second switching sequence. The second switch of a pair of switches has a higher switching power loss than the first switch of the pair of switches during the second switching sequence.

  18. Wear Resistant Rubber Tank Track Pads

    Science.gov (United States)

    1975-10-01

    panels prior to vulcanization-bonding to the ruober stocks; degreasing, glass beadblasting, solvent-wiping, brush application of bonding agent, and...umP! TABLE I? EVALUATION OF SANTOWEB D IN SBR 1500 Physical Properties Teeted at Ambient: Tensile, psl Modulus @100^ Elopgation, psl Modulus

  19. Prolonging contact lens wear and making contact lens wear safer.

    Science.gov (United States)

    Foulks, Gary N

    2006-02-01

    To summarize the present status of safety and efficacy of contact lens wear. Literature review. Ovid Medline searches were performed on records from 1966 through 2005 using keywords: keratitis, contact lens complications, extended-wear contact lenses, and silicone-hydrogel contact lenses. Patients desire comfort, clarity of vision, and prolonged contact lens wear when contact lenses are used to correct refractive error. Practitioners desire patient satisfaction but also require maintenance of the integrity of the eye and no complications that jeopardize vision or health of the eye. Improvements in the oxygen permeability of the contact lens materials, design of the contact lens and its surface, and solutions for the maintenance of the lens have reduced but not eliminated the risks of infection, inflammation, and conjunctival papillary reaction associated with contact lens wear. The lessons of past and recent history suggest that patient education and practitioner participation in the management of contact lens wear continue to be critical factors for patient satisfaction and safety in the extended wear of contact lenses. The availability of highly oxygen permeable contact lenses has increased the tolerance and safety of extended contact lens wear, but patient instruction and education in proper use and care of lenses is required and caution is advised.

  20. Corrosion and wear in plasma electrosurgical devices

    Science.gov (United States)

    Gaspredes, J.; Ryan, T. P.; Stalder, K. R.; Woloszko, J.

    2017-02-01

    Data were previously reported on studies of the effects of electrical discharges on the corrosion and wear of simple, single-wire test devices immersed in isotonic saline 1 . This work showed that there are a wide variety of mechanisms that can explain various aspects of electrode mass loss, even with very simple electrode geometries and operating conditions. It was found that the electrode material composition played an important role. Subsequently, our studies were expanded to include more realistic device geometries and operating conditions. This paper shows the results of studies on wear characteristics of electrodes made from a variety of highly corrosion resistant metals and alloys, including Waspaloy, Hastelloy, Inconel, Havar, Monel, and other pure metals such as Hafnium. All of these metals underwent wear testing under clinically relevant conditions. Depending on the operating conditions, multiple discrete physical and chemical effects were observed at different locations on the surface of an individual millimeter-scale device electrode. Scanning electron microscope (SEM) micrographs, Energy-dispersive X-ray spectroscopy (EDS) and area loss data will be presented for a variety of test conditions and electrode materials.

  1. Wear behavior of self-lubricating Fe-Cr-C-Mn-Cu alloys: Smearing effect of second phase particles

    Science.gov (United States)

    Kim, Ki Nam; Kim, Byung Sik; Shin, Gyeong Su; Park, Myung Chul; Lee, Deok Hyun; Kim, Seon Jin

    2011-08-01

    Newly developed self-lubricating Fe-Cr-C-Mn-Cu cast composite alloys were investigated to study the role of Cu-rich second phase particles which smear on the wear surface during sliding. The wear resistance of the material was improved with an increasing copper concentration. The improved wear resistance was probably obtained by forming a protective tribofilm, which prevented metal-to-metal contact through smearing of the embedded Cu-rich second phase particles. This formation of protective oxide films during sliding is likely to improve the wear resistance of austenitic Fe-Cr-C-Mn-Cu cast composite alloys.

  2. Tribocorrosion wear of austenitic and martensitic steels

    Directory of Open Access Journals (Sweden)

    G. Rozing

    2016-07-01

    Full Text Available This paper explores the impact of tribocorrosion wear caused by an aggressive acidic media. Tests were conducted on samples made of stainless steel AISI 316L, 304L and 440C. Austenitic steels were tested in their nitrided state and martensitic in quenched and tempered and then induction hardened state. Electrochemical corrosion resistance testing and analysis of the microstructure and hardness in the cross section was carried out on samples of selected steels. To test the possibility of applying surface modification of selected materials in conditions of use, tests were conducted on samples/parts in a worm press for final pressing.

  3. Wear rates of resin composites.

    Science.gov (United States)

    Barkmeier, W W; Erickson, R I; Latta, M A; Wilwerding, T M

    2013-01-01

    SUMMARY A laboratory study was conducted to examine the wear of resin composite materials using a generalized wear simulation model. Ten specimens each of five resin composites (Esthet•X [EX], Filtek Supreme Plus [SP], Filtek Z250 [Z2], Tetric EvoCeram [EC], and Z100 Restorative [Z1]) were subjected to wear challenges of 100,000, 400,000, 800,000, and 1,200,000 cycles. The materials were placed in cylinder-shaped stainless-steel fixtures, and wear was generated using a flat stainless-steel antagonist in a slurry of polymethylmethacrylate beads. Wear (mean facet depth [μm] and volume loss [mm(3)]) was determined using a noncontact profilometer (Proscan 2000) with Proscan and ProForm software. Statistical analysis of the laboratory data using analysis of variance and Tukey's post hoc test showed a significant difference (p<0.05) for mean wear facet depth and volume loss for both the number of cycles and resin composite material. Linear regression analysis was used to develop predictive wear rates and volume loss rates. Linear wear was demonstrated with correlation coefficients (R(2)) ranging from 0.914 to 0.995. Mean wear values (mean facet depth [μm]) and standard deviations (SD) for 1200K cycles were as follows: Z1 13.9 (2.0), Z2 26.7 (2.7), SP 30.1 (4.1), EC 31.8 (2.3), and EX 67.5 (8.2). Volume loss (mm(3)) and SDs for 1200K cycles were as follows: Z1 0.248 (0.036), Z2 0.477 (0.044), SP 0.541 (0.072), EC 0.584 (0.037), and EX 1.162 (0.139). The wear rate (μm) and volume loss rate (mm(3)) per 100,000 cycles for the five resin composites were as follows: wear rate Z1 0.58, EC 1.27, Z2 1.49, SP 1.62, and EX 4.35, and volume loss rate Z1 0.009, EC 0.024, Z2 0.028, SP 0.029, and EX 0.075. The generalized wear model appears to be an excellent method for measuring relative wear of resin composite materials.

  4. Anti-wear properties of the molluscan shell Scapharca subcrenata: Influence of surface morphology, structure and organic material on the elementary wear process

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Limei, E-mail: lmtian@jlu.edu.cn [Key Laboratory of Bionic Engineering (Jilin University), Ministry of Education, Changchun 130022 (China); Tian, Ximei, E-mail: txm@jlu.edu.cn [Secretariat of the International Society of Bionic Engineering, Jilin University, Changchun 130012 (China); Wang, Yinci [Key Laboratory of Bionic Engineering (Jilin University), Ministry of Education, Changchun 130022 (China); Hu, Guangliang, E-mail: guoliang_huu@163.com [School of Automobile and Traffic Engineering, Jiangsu University, Zhenjiang 212013 (China); Ren, Luquan, E-mail: lqren@jlu.edu.cn [Key Laboratory of Bionic Engineering (Jilin University), Ministry of Education, Changchun 130022 (China)

    2014-09-01

    As a typical natural biological mineralisation material, molluscan shells have excellent wear-resistance properties that result from the interactions amongst biological coupling elements such as morphology, structure and material. The in-depth study of the wear-resistance performance of shells and the contribution made by each coupling element may help to promote the development of new bionic wear-resistant devices. The objective of this study was to investigate the influence of surface morphology (rib distribution on the shell), structure (rib coupled with nodules) and material (organic matter) on the anti-wear performance of the molluscan Scapharca subcrenata shell. The effect and contribution of each of these biological coupling elements were systematically investigated using the comparative experiment method. All three were found to exert significant effects on the shell's wear-resistance ability, and their individual contributions to that ability were revealed. Organic material can be classified as the principal coupling element, rib morphology as the secondary coupling element and the combined rib-nodule structure as the general coupling element. - Highlights: • We found that the S. subcrenata shell has an anti-wear ability. • This is related to the morphology, structure and material of the shell surface. • Organic material is the principal coupling element in its anti-wear ability. • Rib morphology could be considered the secondary coupling element. • The coupled structure could be regarded as the general coupling element.

  5. Effect of Cl on the corrosive wear of AISI 321 stainless steel in ...

    Indian Academy of Sciences (India)

    Unknown

    2002-07-25

    Jul 25, 2002 ... corrosive wear rate, the load bearing capacity of passive film and the relationship between pitting and corrosive wear. Neville and Hodgkiess (1999) made a study of the erosion–corrosion behaviour of two nominally corrosion resistant alloys. The experiments comprised of exposure to an impinging jet of ...

  6. Materials Aspects of Hydro-Abrasive Wear in the Dredging Industry

    NARCIS (Netherlands)

    Liu, Y.

    2017-01-01

    A better understanding of the wear mechanism of materials is essential to selecting suitable materials to prolong service time and reduce costs. Wear resistance is not an intrinsic material property but a response to a system including multiples parameters determined by the material, the counter

  7. Processing and study of the wear and friction behaviour of discrete ...

    Indian Academy of Sciences (India)

    Wear surface morphology studies were also carried out using stereoscope and scanning electron microscope. Our experiments lead to the following important results: (1) the large size h-BN particle improves the densification of the hybridized composite layer and provides higher wear resistance and better braking ...

  8. Abrasive wear behavior of heat-treated ABC-silicon carbide

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiao Feng; Lee, Gun Y.; Chen, Da; Ritchie, Robert O.; De Jonghe, Lutgard C.

    2002-06-17

    Hot-pressed silicon carbide, containing aluminum, boron, and carbon additives (ABC-SiC), was subjected to three-body and two-body wear testing using diamond abrasives over a range of sizes. In general, the wear resistance of ABC-SiC, with suitable heat treatment, was superior to that of commercial SiC.

  9. New Challenges in Tribology: Wear Assessment Using 3D Optical Scanners.

    Science.gov (United States)

    Valigi, Maria Cristina; Logozzo, Silvia; Affatato, Saverio

    2017-05-18

    Wear is a significant mechanical and clinical problem. To acquire further knowledge on the tribological phenomena that involve freeform mechanical components or medical prostheses, wear tests are performed on biomedical and industrial materials in order to solve or reduce failures or malfunctions due to material loss. Scientific and technological advances in the field of optical scanning allow the application of innovative devices for wear measurements, leading to improvements that were unimaginable until a few years ago. It is therefore important to develop techniques, based on new instrumentations, for more accurate and reproducible measurements of wear. The aim of this work is to discuss the use of innovative 3D optical scanners and an experimental procedure to detect and evaluate wear, comparing this technique with other wear evaluation methods for industrial components and biomedical devices.

  10. Prediction of Polyethylene Wear Rates from Gait Biomechanics and Implant Positioning in Total Hip Replacement.

    Science.gov (United States)

    Ardestani, Marzieh M; Amenábar Edwards, Pedro P; Wimmer, Markus A

    2017-08-01

    Patient-specific gait and surgical variables are known to play an important role in wear of total hip replacements (THR). However a rigorous model, capable of predicting wear rate based on a comprehensive set of subject-specific gait and component-positioning variables, has to our knowledge, not been reported. (1) Are there any differences between patients with high, moderate, and low wear rate in terms of gait and/or positioning variables? (2) Can we design a model to predict the wear rate based on gait and positioning variables? (3) Which group of wear factors (gait or positioning) contributes more to the wear rate? Data on patients undergoing primary unilateral THR who performed a postoperative gait test were screened for inclusion. We included patients with a 28-mm metal head and a hip cup made of noncrosslinked polyethylene (GUR 415 and 1050) from a single manufacturer (Zimmer, Inc). To calculate wear rates from radiographs, inclusion called for patients with a series of standing radiographs taken more than 1 year after surgery. Further, exclusion criteria were established to obtain reasonably reliable and homogeneous wear readings. Seventy-three (83% of included) patients met all criteria, and the final dataset consisted of 43 males and 30 females, 69 ± 10 years old, with a BMI of 27.3 ± 4.7 kg/m(2). Wear rates of these patients were determined based on the relative displacement of the femoral head with regard to the cup using a validated computer-assisted X-ray wear-analysis suite. Three groups with low ( 0.2 mm/year) wear were established. Wear prediction followed a two-step process: (1) linear discriminant analysis to estimate the level of wear (low, moderate, or high), and (2) multiple linear and nonlinear regression modeling to predict the exact wear rate from gait and implant-positioning variables for each level of wear. There were no group differences for positioning and gait suggesting that wear differences are caused by a combination of wear

  11. Analysis of Impact of Chosen Parameters on the Wear of Camshft

    Directory of Open Access Journals (Sweden)

    Burdzik R.

    2014-10-01

    Full Text Available The paper provides an analysis of the reasons for excessive wear of the camshafts system components based on models developed to describe the impact of selected material, technological and operational factors. The subject of the research was wear of camshaft cams studied in accordance with results of operation tests. Based on the said tests, the dependence of wear intensity of cams from their angular position was established. The respective calculation results enabled the function of cam fallibility to be determined.

  12. Clinical measurement of tooth wear: Tooth Wear Indices

    OpenAIRE

    J. López Frías; Castellanos Cosano, Lizett; Martín González, Jenifer; Llamas Carreras, José María; Segura-Egea, Juan J.

    2012-01-01

    Attrition, erosion, and abrasion result in alterations to the tooth and manifest as tooth wear. Each classification corresponds to a different process with specific clinical features. Classifications made so far have no accurate prevalence data because the indexes do not necessarily measure a specific etiology, or because the study populations can be diverse in age and characteristics. Tooth wears (attrition, erosion and abrasion) is perceived internationally as a growing problem. However, th...

  13. Corrosion and wear behaviour of multilayer pulse electrodeposited ...

    Indian Academy of Sciences (India)

    persion of nanoparticles in the metal matrix and affected coating microstructure and surface morphology [22]. The. Ni–Al2O3 nanocomposite coatings were widely studied due to their hardness and wear and corrosion resistance compared to electrodeposited pure nickel coatings [23]. The researchers have focused on the ...

  14. Manganese steel in impact wear testing; Manganhartstahl in Stossverschleisstest

    Energy Technology Data Exchange (ETDEWEB)

    Patzelt, B.; Hemmann, U.; Deters, L. [Magdeburg Univ. (Germany). Inst. fuer Maschinenkonstruktion

    2000-12-01

    Beating arms in impact crushers show high wear. In order to simulate the process of the mainly occuring impact wear, experimental investigations with a special test device were carried out. With this 11 different charges of manganese steel differing in their chemical composition were tested. The different chemical composition of the charges led to different results concerning the wear resistance. A significant interrelationship between wear resistance and macro-hardness of the charges of the manganese steel could be detected. With a faster rotor speed a considerable increase of wear could be determined as well. Microscopical investigations on worn test pieces exhibit a typical embedding of small particles of concrete into the metal matrix. (orig.) [German] Die Schlagleisten in Prallbrechern unterliegen einen hohen Verschleiss. Um den Prozess des hauptsaechlich auftretenden Stossverschleisses zu simulieren, wurden Modelluntersuchungen mit einer speziellen Pruefeinrichtung durchgefuehrt. Dabei konnten 11 verschiedene Chargen von Manganhartstahl, die sich im wesentlichen in ihrer chemischen Zusammensetzung unterschieden, untersucht werden. Die unterschiedliche chemische Zusammensetzung der einzelnen Chargen fuehrte zu unterschiedlichen Ergebnissen hinsichtlich der Verschleissbestaendigkeit der einzelnen Modellschlagleisten. Hierbei ist ein signifikanter Zusammenhang zwischen der Verschleissbestaendigkeit und der Makrohaerte der Manganhartstaehle zu erkennen. Die Umfangsgeschwindigkeit des Rotors der Pruefeinrichtung beeinflusst ebenfalls das Verschleissverhalten, und zwar fuehrte eine hoehere Umfangsgeschwindigkeit zu hoeherem Verschleiss. Mikroskopische Untersuchungen an geschaedigten Probekoerpern zeigten ein Einbetten von kleinsten Partikeln aus Beton im oberflaechennahen Stoffbereich der Metallmatrix. (orig.)

  15. Nuclear and cytoplasmic genome components of Solanum tuberosum + S. chacoense somatic hybrids and three SSR alleles related to bacterial wilt resistance.

    Science.gov (United States)

    Chen, Lin; Guo, Xianpu; Xie, Conghua; He, Li; Cai, Xingkui; Tian, Lingli; Song, Botao; Liu, Jun

    2013-07-01

    The somatic hybrids were derived previously from protoplast fusion between Solanum tuberosum and S. chacoense to gain the bacterial wilt resistance from the wild species. The genome components analysis in the present research was to clarify the nuclear and cytoplasmic composition of the hybrids, to explore the molecular markers associated with the resistance, and provide information for better use of these hybrids in potato breeding. One hundred and eight nuclear SSR markers and five cytoplasmic specific primers polymorphic between the fusion parents were used to detect the genome components of 44 somatic hybrids. The bacterial wilt resistance was assessed thrice by inoculating the in vitro plants with a bacterial suspension of race 1. The disease index, relative disease index, and resistance level were assigned to each hybrid, which were further analyzed in relation to the molecular markers for elucidating the potential genetic base of the resistance. All of the 317 parental unique nuclear SSR alleles appeared in the somatic hybrids with some variations in the number of bands detected. Nearly 80 % of the hybrids randomly showed the chloroplast pattern of one parent, and most of the hybrids exhibited a fused mitochondrial DNA pattern. One hundred and nine specific SSR alleles of S. chacoense were analyzed for their relationship with the disease index of the hybrids, and three alleles were identified to be significantly associated with the resistance. Selection for the resistant SSR alleles of S. chacoense may increase the possibility of producing resistant pedigrees.

  16. Tool Wear in Friction Drilling

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Scott F [ORNL; Blau, Peter Julian [ORNL; Shih, Albert J. [University of Michigan

    2007-01-01

    This study investigated the wear of carbide tools used in friction drilling, a nontraditional hole-making process. In friction drilling, a rotating conical tool uses the heat generated by friction to soften and penetrate a thin workpiece and create a bushing without generating chips. The wear of a hard tungsten carbide tool used for friction drilling a low carbon steel workpiece has been investigated. Tool wear characteristics were studied by measuring its weight change, detecting changes in its shape with a coordinate measuring machine, and making observations of wear damage using scanning electron microscopy. Energy dispersive spectroscopy was applied to analyze the change in chemical composition of the tool surface due to drilling. In addition, the thrust force and torque during drilling and the hole size were measured periodically to monitor the effects of tool wear. Results indicate that the carbide tool is durable, showing minimal tool wear after drilling 11000 holes, but observations also indicate progressively severe abrasive grooving on the tool tip.

  17. The Arabidopsis Mediator Complex Subunit16 Is a Key Component of Basal Resistance against the Necrotrophic Fungal Pathogen Sclerotinia sclerotiorum.

    Science.gov (United States)

    Wang, Chenggang; Yao, Jin; Du, Xuezhu; Zhang, Yanping; Sun, Yijun; Rollins, Jeffrey A; Mou, Zhonglin

    2015-09-01

    Although Sclerotinia sclerotiorum is a devastating necrotrophic fungal plant pathogen in agriculture, the virulence mechanisms utilized by S. sclerotiorum and the host defense mechanisms against this pathogen have not been fully understood. Here, we report that the Arabidopsis (Arabidopsis thaliana) Mediator complex subunit MED16 is a key component of basal resistance against S. sclerotiorum. Mutants of MED16 are markedly more susceptible to S. sclerotiorum than mutants of 13 other Mediator subunits, and med16 has a much stronger effect on S. sclerotiorum-induced transcriptome changes compared with med8, a mutation not altering susceptibility to S. sclerotiorum. Interestingly, med16 is also more susceptible to S. sclerotiorum than coronatine-insensitive1-1 (coi1-1), which is the most susceptible mutant reported so far. Although the jasmonic acid (JA)/ethylene (ET) defense pathway marker gene PLANT DEFENSIN1.2 (PDF1.2) cannot be induced in either med16 or coi1-1, basal transcript levels of PDF1.2 in med16 are significantly lower than in coi1-1. Furthermore, ET-induced suppression of JA-activated wound responses is compromised in med16, suggesting a role for MED16 in JA-ET cross talk. Additionally, MED16 is required for the recruitment of RNA polymerase II to PDF1.2 and OCTADECANOID-RESPONSIVE ARABIDOPSIS ETHYLENE/ETHYLENE-RESPONSIVE FACTOR59 (ORA59), two target genes of both JA/ET-mediated and the transcription factor WRKY33-activated defense pathways. Finally, MED16 is physically associated with WRKY33 in yeast and in planta, and WRKY33-activated transcription of PDF1.2 and ORA59 as well as resistance to S. sclerotiorum depends on MED16. Taken together, these results indicate that MED16 regulates resistance to S. sclerotiorum by governing both JA/ET-mediated and WRKY33-activated defense signaling in Arabidopsis. © 2015 American Society of Plant Biologists. All Rights Reserved.

  18. Combination Thermal Barrier And Wear Coatings For Engines

    Science.gov (United States)

    Weingart, Mike; Moller, Paul

    1995-01-01

    Thermal-barrier layers covered with self-lubricating surface layers. Zirconia thermal-barrier coat applied to surface of combustion chamber in engine by plasma-arc spraying. Then PS-200 plasma-arc sprayed onto zirconia. Self-lubricating coat prevents sliding contact between thermal barrier and piston ring, effectively preventing both wear and production of additional heat via friction. Other combinations of thermal-barrier and self-lubricating, wear-resistant coating materials used as long as two materials adhere to each other, applied by use of similar or compatible processes, have similar coefficients of thermal expansion, sufficiently strong at high temperatures, and affordable.

  19. Correction of error in two-dimensional wear measurements of cemented hip arthroplasties

    NARCIS (Netherlands)

    The, Bertram; Mol, Linda; Diercks, Ron L.; van Ooijen, Peter M. A.; Verdonschot, Nico

    The irregularity of individual wear patterns of total hip prostheses seen during patient followup may result partially from differences in radiographic projection of the components between radiographs. A method to adjust for this source of error would increase the value of individual wear curves. We

  20. A two-component histidine kinase Shk1 controls stress response, sclerotial formation and fungicide resistance in Sclerotinia sclerotiorum.

    Science.gov (United States)

    Duan, Yabing; Ge, Changyan; Liu, Shengming; Wang, Jianxin; Zhou, Mingguo

    2013-09-01

    Fungal histidine kinases (HKs) are involved in osmotic and oxidative stress responses, hyphal development, fungicide sensitivity and virulence. Members of HK class III are known to signal through the high-osmolarity glycerol mitogen-activated protein kinase (HOG MAPK). In this study, we characterized the Shk1 gene (SS1G_12694.3), which encodes a putative class III HK, from the plant pathogen Sclerotinia sclerotiorum. Disruption of Shk1 resulted in resistance to phenylpyrrole and dicarboximide fungicides and increased sensitivity to hyperosmotic stress and H2 O2 -induced oxidative stress. The Shk1 mutant showed a significant reduction in vegetative hyphal growth and was unable to produce sclerotia. Quantitative real-time polymerase chain reaction (qRT-PCR and glycerol determination assays showed that the expression of SsHOG1 (the last kinase of the Hog pathway) and glycerol accumulation were regulated by the Shk1 gene, but PAK (p21-activated kinase) was not. In addition, the Shk1 mutant showed no change in virulence. All the defects were restored by genetic complementation of the Shk1 deletion mutant with the wild-type Shk1 gene. These findings indicate that Shk1 is involved in vegetative differentiation, sclerotial formation, glycerol accumulation and adaption to hyperosmotic and oxidative stresses, and to fungicides, in S. sclerotiorum. Taken together, our results demonstrate, for the first time, the role of two-component HKs in Sclerotinia. © 2013 BSPP AND JOHN WILEY & SONS LTD.

  1. On the friction and sliding wear of rubber/layered silicate nanocomposites

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available The dry sliding and friction behaviors of organoclay modified hydrogenated nitrile (HNBR and ethylene/propylene/diene (EPDM rubbers were studied using a pin (steel-on-plate(rubber sheet test configuration. It was found that the organoclay modification may improve or deteriorate the resistance to wear of rubbers. The resistance to wear was adversely affected by pronounced intercalation/exfoliation and two-dimensional alignment of the clay layers (i.e. normal to the moving pin. This result is in analogy with the directional dependence of the wear performance of fiber-reinforced composite laminates.

  2. Reducing Friction and Wear of Tribological Systems through Hybrid Tribofilm Consisting of Coating and Lubricants

    Directory of Open Access Journals (Sweden)

    Shuichiro Yazawa

    2014-06-01

    Full Text Available The role of surface protective additives becomes vital when operating conditions become severe and moving components operate in a boundary lubrication regime. After protecting film is slowly removed by rubbing, it can regenerate through the tribochemical reaction of the additives at the contact. However, there are limitations about the regeneration of the protecting film when additives are totally consumed. On the other hand, there are a lot of hard coatings to protect the steel surface from wear. These can enable the functioning of tribological systems, even in adverse lubrication conditions. However, hard coatings usually make the friction coefficient higher, because of their high interfacial shear strength. Amongst hard coatings, diamond-like carbon (DLC is widely used, because of its relatively low friction and superior wear resistance. In practice, conventional lubricants that are essentially formulated for a steel/steel surface are still used for lubricating machine component surfaces provided with protective coatings, such as DLCs, despite the fact that the surface properties of coatings are quite different from those of steel. It is therefore important that the design of additive molecules and their interaction with coatings should be re-considered. The main aim of this paper is to discuss the DLC and the additive combination that enable tribofilm formation and effective lubrication of tribological systems.

  3. Wear of Polished Steel Surfaces in Dry Friction Linear Contact on Polimer Composites with Glass Fibres

    Directory of Open Access Journals (Sweden)

    D. Rus

    2013-12-01

    Full Text Available It is generally known that the friction and wear between polymers and polished steel surfaces has a special character, the behaviour to friction and wear of a certain polymer might not be valid for a different polymer, moreover in dry friction conditions. In this paper, we study the reaction to wear of certain polymers with short glass fibres on different steel surfaces, considering the linear friction contact, observing the friction influence over the metallic surfaces wear. The paper includes also its analysis over the steel’s wear from different points of view: the reinforcement content influence and tribological parameters (load, contact pressure, sliding speed, contact temperature, etc.. Thus, we present our findings related to the fact that the abrasive component of the friction force is more significant than the adhesive component, which generally is specific to the polymers’ friction. Our detections also state that, in the case of the polyamide with 30% glass fibres, the steel surface linear wear rate order are of 10-4 mm/h, respectively the order of volumetric wear rate is of 10-6 cm3 /h. The resulting volumetric wear coefficients are of the order (10-11 – 10-12 cm3/cm and respectively linear wear coefficients of 10-9 mm/cm.

  4. Wear prediction on total ankle replacement effect of design parameters

    CERN Document Server

    Saad, Amir Putra Bin Md; Harun, Muhamad Noor; Kadir, Mohammed Rafiq Abdul

    2016-01-01

    This book develops and analyses computational wear simulations of the total ankle replacement for the stance phase of gait cycle. The emphasis is put on the relevant design parameters. The book presents a model consisting of three components; tibial, bearing and talar representing their physiological functions.

  5. Development of the white cast iron with niobium alloy, heat treating, to wear of the abrasive resistance; Desenvolvimento de uma liga de ferro fundido branco alto cromo com niobio, tratada termicamente, para resistencia ao desgaste abrasivo

    Energy Technology Data Exchange (ETDEWEB)

    Farah, Alessandro Fraga

    1997-07-01

    This work presents the heat treatment and abrasion tests results of a white cast iron with niobium alloy. The hardening heat treatment were made 950, 1000, 1050 e 110 deg C temperatures cooled by forced air. The tempering treatment were made at 450, 500 e 550 deg C temperatures. The heat treating alloy were compared, in the abrasive tests, with commercial alloys used as hardfacing by welding process in wear pieces. The abrasion tests was realized in pin on disk test. Additional tests were carried out for microstructural characterization to identify the different phases presents in the alloys. In a general way, the alloy studies showed the best wear rate for the heat treatments that results in higher hardness. It performance was superior than that of the commercial alloys. (author)

  6. Corrosion and wear behaviours of a reactive-sputter-deposited Ta2O5 nanoceramic coating

    Science.gov (United States)

    Hu, Wei; Xu, Jiang; Lu, Xiaolin; Hu, Dongsheng; Tao, Hongliang; Munroe, Paul; Xie, Zong-Han

    2016-04-01

    In order to improve the wear and corrosion resistance of Ti-6Al-4V, a novel β-Ta2O5 nanoceramic coating was synthesised using reactive sputter deposition enabled by double glow discharge plasma technique. The surface topography, chemical composition, and microstructure of the newly developed coating were characterised by a variety of surface analytical techniques. The coating microstructure was found to exhibit a compact striated pattern extending in a direction perpendicular to coating surface, which is composed of equiaxed β-Ta2O5 grains with an average grain size of ∼20 nm, well adhered to the Ti-6A1-4V substrate. The hardness and the Young's modulus of the as-deposited coating were obtained by nanoindentation, and the adhesion strength between the coating and substrate was determined by a scratch tester. The dry sliding wear behaviours of the coating were investigated at room temperature against Si3N4 ceramic balls at room temperature under applied loads ranging from 2.3 N to 5.3 N using a ball-on-disc tribometer. The specific wear rates of the coating exhibited only a slight increase with applied normal load, and were shown to be two orders of magnitude lower than that for Ti-6Al-4V under the same loading condition. Furthermore, the electrochemical behaviour of the coating immersed in 3.5 wt.% NaCl solution was systematically examined by using a range of complementary electrochemical techniques including potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS), Mott-Schottky analysis as well as potential of zero charge (PZC). The results showed that the corrosion resistance of the β-Ta2O5 nanoceramic coating was better than that of Ti-6Al-4V alloy in 3.5 wt.% NaCl solution. Hence, by possessing higher mechanical properties and good wear and corrosion resistance, the β-Ta2O5 nanoceramic coating is considered to be a promising candidate for protection of engineering components operating under harsh conditions.

  7. Public Commitment, Resistance to Advertising, and Leisure Promotion in a School-Based Drug Abuse Prevention Program: A Component Dismantling Study

    Science.gov (United States)

    Hernández-Serrano, Olga; Griffin, Kenneth W.; García-Fernández, José Manuel; Espada, Mireia; Orgilés José P.

    2013-01-01

    The objective of the present study was to examine the contribution of three intervention components (public commitment, resistance to advertising, and leisure promotion) on alcohol and protective variables in a school-based substance use prevention program. Participants included 480 Spanish students aged from 14 to 16 who received the…

  8. Tribological behavior and wear mechanisms of TiN/TiCN/TiN multilayer coatings

    Science.gov (United States)

    Su, Y. L.; Kao, W. H.

    1998-10-01

    This work employs the PVD process to deposit coatings of single layer TiN, binary layer TiN/TiCN, multilayer TiN⇔⇔N, and sequenced TiN⇔CN⇔N multilayer coatings with variable individual TiN-layer and TiCN-layer thicknesses on tungsten carbide disks and inserts. Also investigated are the fracture mechanisms and the influence of sequence and thickness of these coatings on cylinder-on-disk, line-contact wear mode and ball-on-disk, point-contact wear mode through SRV reciprocating wear tests. Actual milling tests identify wear performance. Experimental results indicate that the coating with a total thickness of 7 Μm and layer sequence TiN/TiCN/TiN exhibits good wear resistance on SRV wear test and milling test. The thickest multilayer TiN/Ti/TiN coating, although having the highest hardness, has the worst wear resistance for all tests. No-tably zero-wear performance was observed for all coating disks under cutting fluid lubricated condition due to the transferred layers formed between the contact interface.

  9. Two-body and three-body wear of glass ionomer cements.

    Science.gov (United States)

    Kunzelmann, K H; Bürkle, V; Bauer, C

    2003-11-01

    Glass ionomer cements (GIC) have been modified in an attempt to improve their mechanical properties. The objective of the present paper was to compare the two-body and three-body wear of four modified GIC. The tested materials were Fuji IX (GC Corporation), Hi-Fi (Shofu) and Ketac Molar Aplicap (3M/ESPE). The cermet cement Ketac Silver Maxicap (3M/ESPE) was used as reference material. Two-body wear tests were carried out in the computer controlled 'artificial mouth' of the Munich Dental School, three-body wear was tested with the ACTA wear machine. The resulting average two-body wear rates (in microm) were: Fuji IX 327 (SD +/- 82) Ketac Molar 379 (SD +/- 94) Ketac silver 449 (SD +/- 127). The differences between the materials were significant (P Ketac Molar and Hi-Fi. The average three-body wear rates (in microm) were: Hi-Fi 30 (SD +/- 10) Ketac Molar +/- 42 (SD +/- 12) Ketac silver 73 (SD +/- 23). The difference between Ketac silver and the three other materials was significant (P Ketac Molar and Fuji IX. As Ketac Molar, Hi-Fi and Fuji IX show better wear resistance compared to Ketac silver both in occlusal-contact and contact-free areas, it may be assumed that the wear resistance of a glass ionomer cement may be improved more by changing the powder: liquid ratio than by incorporating silver particles into the glass powder.

  10. An evaluation of the using possibilities of the carbonitrided simple steels instead of carburized low alloy steels (wear properties)

    Science.gov (United States)

    Karamiş, M. B.; İpek, R.

    1997-09-01

    In this study, the wear behaviour of carburized and carbonitrided AISI 1020 and 5115 steels, widely used in industry, were investigated. The surface properties, microstructures, hardness distributions and wear behaviour of the treated steels were determined as well as the wear characteristics and weight losses of the treated samples as a function of wear test durations and loads. The results indicated that the surface of carbonitrided steel have ɛ-carbonitride compound layer and diffusion zone with chromium iron carbide (Cr, Fe)7C3, chromium carbide nitride (Cr62C3 · 5N0.3), chromium nitride (Cr2N), [Cr, Fe(2N1...x)] and Fe2N phases. The surface hardness and wear resistance of the carbonitrided samples are higher than those of the carburized samples. The carbonitrided 5115 steel has the highest wear resistance followed by carburized 5115, carbonitrided 1020 and carburized 1020 respectively.

  11. Relation between in-vitro wear and nanomechanical properties of commercial light-cured dental composites coated with surface sealants

    Directory of Open Access Journals (Sweden)

    Emanuel Santos Jr

    2013-01-01

    Full Text Available This work investigates the correlation between the in-vitro wear resistance and the nanomechanical properties of dental sealants commercially available. Mechanical properties, namely hardness (H and elastic modulus (E, were assessed by nanoindentation technique. The coated samples presented lower H and E values than the Z250 composite resin substrate. Such measurements were used to calculate H/E ratios. Wear tests were carried out in water by using a pin-on-plate apparatus. Scars formed on the samples were qualitatively examined by optical microscopy, while their wear depths were measured by contact profilometry. Based on the findings, an empirical correlation between the wear depths and H/E was obtained. A high H/E ratio was associated to surfaces with enhanced wear resistance. For the tribological conditions here employed, the H/E ratio could be, therefore, considered a useful parameter for ranking the in-vitro wear of dental sealants.

  12. A Multiple Model Prediction Algorithm for CNC Machine Wear PHM

    Directory of Open Access Journals (Sweden)

    Huimin Chen

    2011-01-01

    Full Text Available The 2010 PHM data challenge focuses on the remaining useful life (RUL estimation for cutters of a high speed CNC milling machine using measurements from dynamometer, accelerometer, and acoustic emission sensors. We present a multiple model approach for wear depth estimation of milling machine cutters using the provided data. The feature selection, initial wear estimation and multiple model fusion components of the proposed algorithm are explained in details and compared with several alternative methods using the training data. The final submission ranked #2 among professional and student participants and the method is applicable to other data driven PHM problems.

  13. Multiscale Modeling of Wear Degradation

    KAUST Repository

    Moraes, Alvaro

    2016-01-06

    Cylinder liners of diesel engines used for marine propulsion are naturally subjected to a wear process, and may fail when their wear exceeds a specified limit. Since failures often represent high economical costs, it is utterly important to predict and avoid them. In this work [4], we model the wear process using a pure jump process. Therefore, the inference goal here is to estimate: the number of possible jumps, its sizes, the coefficients and the shapes of the jump intensities. We propose a multiscale approach for the inference problem that can be seen as an indirect inference scheme. We found that using a Gaussian approximation based on moment expansions, it is possible to accurately estimate the jump intensities and the jump amplitudes. We obtained results equivalent to the state of the art but using a simpler and less expensive approach.

  14. Multiscale Modeling of Wear Degradation

    KAUST Repository

    Moraes, Alvaro

    2015-01-07

    Cylinder liners of diesel engines used for marine propulsion are naturally subjected to a wear process, and may fail when their wear exceeds a specified limit. Since failures often represent high economical costs, it is utterly important to predict and avoid them. In this work [4], we model the wear process using a pure jump process. Therefore, the inference goal here is to estimate: the number of possible jumps, its sizes, the coefficients and the shapes of the jump intensities. We propose a multiscale approach for the inference problem that can be seen as an indirect inference scheme. We found that using a Gaussian approximation based on moment expansions, it is possible to accurately estimate the jump intensities and the jump amplitudes. We obtained results equivalent to the state of the art but using a simpler and less expensive approach.

  15. Multiscale Modeling of Wear Degradation

    KAUST Repository

    Moraes, Alvaro

    2014-01-06

    Cylinder liners of diesel engines used for marine propulsion are naturally subjected to a wear process, and may fail when their wear exceeds a specified limit. Since failures often represent high economical costs, it is utterly important to predict and avoid them. In this work [4], we model the wear process using a pure jump process. Therefore, the inference goal here is to estimate: the number of possible jumps, its sizes, the coefficients and the shapes of the jump intensities. We propose a multiscale approach for the inference problem that can be seen as an indirect inference scheme. We found that using a Gaussian approximation based on moment expansions, it is possible to accurately estimate the jump intensities and the jump amplitudes. We obtained results equivalent to the state of the art but using a simpler and less expensive approach.

  16. Wear Enhancement of Wheel-Rail Interaction by Ultrasonic Nanocrystalline Surface Modification Technique

    Directory of Open Access Journals (Sweden)

    Seky Chang

    2017-02-01

    Full Text Available In this study, an ultrasonic nanocrystalline surface modification (UNSM technique was applied to normal and heat-treated rails made of 60 kgK steel to enhance the wear resistance of the wheel-rail interaction. The hardness and compressive residual stress values of the untreated and UNSM-treated rails were measured by the Brinell hardness tester and X-ray diffraction technique, respectively. It was found, according to the measurement results, that the hardness was increased by about 20% and 8%, whereas the compressive residual stress was induced by about 52% and 62% for the UNSM-treated normal and heat-treated rails, respectively. The UNSM-treated normal rail showed a slightly higher hardness than the heat-treated rail. The wear resistance of rails with respect to rotating speed and rolling time was assessed using a rolling contact wear (RCW tester under dry conditions. The RCW test results revealed that the wear of the UNSM-treated rails was enhanced in comparison with those of the untreated rails. Also, the wear amount of the rails was increased with increasing the rotation speed. The UNSM-treated normal rail exhibited the highest wear resistance with respect to the rotation speed. The wear mechanisms of the rails are also discussed based on microscopic images of the worn out surfaces.

  17. Wear Enhancement of Wheel-Rail Interaction by Ultrasonic Nanocrystalline Surface Modification Technique.

    Science.gov (United States)

    Chang, Seky; Pyun, Young-Sik; Amanov, Auezhan

    2017-02-16

    In this study, an ultrasonic nanocrystalline surface modification (UNSM) technique was applied to normal and heat-treated rails made of 60 kgK steel to enhance the wear resistance of the wheel-rail interaction. The hardness and compressive residual stress values of the untreated and UNSM-treated rails were measured by the Brinell hardness tester and X-ray diffraction technique, respectively. It was found, according to the measurement results, that the hardness was increased by about 20% and 8%, whereas the compressive residual stress was induced by about 52% and 62% for the UNSM-treated normal and heat-treated rails, respectively. The UNSM-treated normal rail showed a slightly higher hardness than the heat-treated rail. The wear resistance of rails with respect to rotating speed and rolling time was assessed using a rolling contact wear (RCW) tester under dry conditions. The RCW test results revealed that the wear of the UNSM-treated rails was enhanced in comparison with those of the untreated rails. Also, the wear amount of the rails was increased with increasing the rotation speed. The UNSM-treated normal rail exhibited the highest wear resistance with respect to the rotation speed. The wear mechanisms of the rails are also discussed based on microscopic images of the worn out surfaces.

  18. Combating Wear of ASTM A36 Steel by Surface Modification Using Thermally Sprayed Cermet Coatings

    Directory of Open Access Journals (Sweden)

    Vineet Shibe

    2016-01-01

    Full Text Available Thermal spray coatings can be applied economically on machine parts to enhance their requisite surface properties like wear, corrosion, erosion resistance, and so forth. Detonation gun (D-Gun thermal spray coatings can be applied on the surface of carbon steels to improve their wear resistance. In the present study, alloy powder cermet coatings WC-12% Co and Cr3C2-25% NiCr have been deposited on ASTM A36 steel with D-Gun thermal spray technique. Sliding wear behavior of uncoated ASTM A36 steel and D-Gun sprayed WC-12% Co and Cr3C2-25% NiCr coatings on base material is observed on a Pin-On-Disc Wear Tester. Sliding wear performance of WC-12% Co coating is found to be better than the Cr3C2-25% NiCr coating. Wear performance of both these cermet coatings is found to be better than uncoated ASTM A36 steel. Thermally sprayed WC-12% Co and Cr3C2-25% NiCr cermet coatings using D-Gun thermal spray technique is found to be very useful in improving the sliding wear resistance of ASTM A36 steel.

  19. Wear Behaviour of Iron Matrix Composite Reinforced by ZTA Particles in Impact Abrasion

    Science.gov (United States)

    Qiu, B.; Xing, S. M.; Dong, Q.

    2017-11-01

    Zirconia toughened alumina (ZTA) particles reinforced high chromium cast iron composites (ZTA/Iron composites) were prepared by a two-step processing method, i.e. mixing particles by the molten metal and cohering by high pressure, which based on the squeeze casting process. The impact wear resistance under different impact energies were investigated using dynamically loaded abrasive wear tester at room temperature. For comparison, the wear tests of high chromium cast iron were also carried out under the same conditions. Worn surfaces of the samples were observed under scanning electron microscopy equipped with an energy dispersive detector. The results showed that the composites have better impact wear resistance than that of high Cr cast iron regardless of impact energy level, and the wear resistance of the two materials all decrease with the increase of the impact energy. The main wear mechanisms of the high Cr cast iron were micro-cutting and fatigue peeling, while the wear of composites occurred through micro-cutting of the matrix (lower impact energy) and breaking and shedding of the reinforced particles (higher impact energy).

  20. Wear Enhancement of Wheel-Rail Interaction by Ultrasonic Nanocrystalline Surface Modification Technique

    Science.gov (United States)

    Chang, Seky; Pyun, Young-Sik; Amanov, Auezhan

    2017-01-01

    In this study, an ultrasonic nanocrystalline surface modification (UNSM) technique was applied to normal and heat-treated rails made of 60 kgK steel to enhance the wear resistance of the wheel-rail interaction. The hardness and compressive residual stress values of the untreated and UNSM-treated rails were measured by the Brinell hardness tester and X-ray diffraction technique, respectively. It was found, according to the measurement results, that the hardness was increased by about 20% and 8%, whereas the compressive residual stress was induced by about 52% and 62% for the UNSM-treated normal and heat-treated rails, respectively. The UNSM-treated normal rail showed a slightly higher hardness than the heat-treated rail. The wear resistance of rails with respect to rotating speed and rolling time was assessed using a rolling contact wear (RCW) tester under dry conditions. The RCW test results revealed that the wear of the UNSM-treated rails was enhanced in comparison with those of the untreated rails. Also, the wear amount of the rails was increased with increasing the rotation speed. The UNSM-treated normal rail exhibited the highest wear resistance with respect to the rotation speed. The wear mechanisms of the rails are also discussed based on microscopic images of the worn out surfaces. PMID:28772549