Wear Response of Aluminium 6061 Composite Reinforced with Red Mud at Elevated Temperature

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R. Dabral

2017-09-01

Full Text Available The present work is focused on the investigations on dry sliding wear behaviour of aluminium metal matrix composite at room and elevated temperature. Aluminium metal matrix composites reinforced with red mud are prepared by stir casting method. The experiments are planned using Taguchi technique. An orthogonal array, analysis of variance and signal to noise ratio are used to check the influence of wear parameters like temperature, percentage of reinforcement, mesh size, load, sliding distance and sliding speed on dry sliding wear of composites. The optimal testing parameters are found and their values are calculated which are then compared with predicted values. A reasonable agreement is found between predicted and actual values. The model prepared in the present work can be effectively used to predict the specific wear rate of the composites.

Fretting wear of Inconel 625 at high temperature and in high vacuum

International Nuclear Information System (INIS)

Iwabuchi, A.

1985-01-01

The purpose of this work was to investigate the fretting properties of Inconel 625 at high temperature and in high vacuum. Experiments were carried out under constant conditions with a normal load of 14 N and a peak-to-peak slip amplitude of 110 μm and through 6x10 4 cycles. Several environmental conditions were used. Pressure was varied between 10 -3 and 10 5 Pa at temperatures of 20 and 500 0 C. Temperatures up to 500 0 C were also used at pressures of 10 -3 and 10 5 Pa. At 10 -3 Pa and 500 0 C wear loss was negligible but wear scars showed severe damage consisting of deep cracks and accretion of transferred debris. The coefficient of friction then maintained a high value of 1.7 throughout the fretting test. The critical pressure below which oxidation rate becomes reduced is 10 Pa, a value independent of temperature. At pressures below this critical value the coefficient of friction increases steeply and the fretting mechanism changes from one of oxidative wear to one of adhesive wear. A compacted so-called 'glaze' oxide was formed at temperatures above 300 0 C in air (10 5 Pa) and at pressures above 10 3 Pa at 500 0 C. A comparison of results for Inconel 625 with those for S45C and SUS304 steels and Inconel 600 is given. (orig.)

Wirelessly Interrogated Wear or Temperature Sensors

Science.gov (United States)

Woodard, Stanley E.; Taylor, Bryant D.

2010-01-01

Sensors for monitoring surface wear and/or temperature without need for wire connections have been developed. Excitation and interrogation of these sensors are accomplished by means of a magnetic-field-response recorder. In a sensor of the present type as in the previously reported ones, the capacitance and, thus, the resonance frequency, varies as a known function of the quantity of interest that one seeks to determine. Hence, the resonance frequency is measured and used to calculate the quantity of interest.

Wear Behavior of Selected Nuclear Grade Graphites at Room Temperature in Ambient Air Environment

International Nuclear Information System (INIS)

Kim, Eung-Seon; Park, Kwang-Seok; Kim, Yong-Wan

2008-01-01

In a very high temperature reactor (VHTR), graphite will be used not only for as a moderator and reflector but also as a major structural component due to its excellent neutronic, thermal and mechanical properties. In the VHTR, wear of graphite components is inevitable due to a neutron irradiation-induced dimensional change, thermal gradient, relative motions of graphite components and a shock load such as an earthquake. Large wear particles accumulated at the bottom of a reactor can influence the cooling of the lower part and small wear particles accumulated on the primary circuit and heat exchanger tube can make it difficult to inspect the equipment, and also decrease the heat exchange rate. In the present work, preliminary wear tests were performed at room temperature in ambient air environment to understand the basic wear characteristics of selected nuclear grade graphites for the VHTR

Aspects of fretting wear of sprayed cermet coatings

International Nuclear Information System (INIS)

Chivers, T.C.

1985-01-01

Two experimental fretting programmes which investigated aspects of fretting wear of sprayed cermet coatings are reviewed. These programmes were conducted in support of components used in the advanced gas-cooled reactor. It is speculated that the results from these programmes are compatible with a simple two-stage wear model. This model assumes that an initial wear process occurs which is dominated by an interlocking and removal of asperities. Such a phase will be dependent on the superficial contact areas and possibly the interfacial load, but the latter aspect is not considered. This initial wear is of very short duration and is followed by a mild, oxidative, wear mode. Coatings data are also compared with those for structural steels. In short-term low temperature tests it appears that structural steels have comparable performance with the cermet coatings but it is argued that this is an artefact of the wear process. However, at high temperatures (600 0 C) wear of stainless steel could not be determined, the specimens showing a net weight gain. It is concluded that for in-reactor fretting applications cermet coatings will have advantages over structural steels at low temperatures. Even in high temperature regions some operation at low temperatures is experienced and consequently cermet coatings may be useful here also. (orig.)

Skin sites to predict deep-body temperature while wearing firefighters' personal protective equipment during periodical changes in air temperature.

Science.gov (United States)

Kim, Siyeon; Lee, Joo-Young

2016-04-01

The aim of this study was to investigate stable and valid measurement sites of skin temperatures as a non-invasive variable to predict deep-body temperature while wearing firefighters' personal protective equipment (PPE) during air temperature changes. Eight male firefighters participated in an experiment which consisted of 60-min exercise and 10-min recovery while wearing PPE without self-contained breathing apparatus (7.75 kg in total PPE mass). Air temperature was periodically fluctuated from 29.5 to 35.5 °C with an amplitude of 6 °C. Rectal temperature was chosen as a deep-body temperature, and 12 skin temperatures were recorded. The results showed that the forehead and chest were identified as the most valid sites to predict rectal temperature (R(2) = 0.826 and 0.824, respectively) in an environment with periodically fluctuated air temperatures. This study suggests that particular skin temperatures are valid as a non-invasive variable when predicting rectal temperature of an individual wearing PPE in changing ambient temperatures. Practitioner Summary: This study should offer assistance for developing a more reliable indirect indicating system of individual heat strain for firefighters in real time, which can be used practically as a precaution of firefighters' heat-related illness and utilised along with physiological monitoring.

HIGH TEMPERATURE EROSION WEAR OF CERMET PARTICLES REINFORCED SELF-FLUXING ALLOY MATRIX HVOF SPRAYED COATINGS

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Andrei Surzhenkov

2015-09-01

Full Text Available In the present paper, the resistance of high velocity oxy-fuel (HVOF sprayed TiC-NiMo and Cr3C2-Ni cermet particles reinforced NiCrSiB self-fluxing alloy matrix coatings to high temperature erosion wear is studied. Microstructure of the coatings was examined by SEM, phase composition was determined by XRD. A four-channel centrifugal particle accelerator was applied to study the high temperature erosion wear of the coatings. The impact angles were 30 and 90 degrees, initial particle velocity was 50 m/s, temperature of the test - 650 degrees. Volume wear of the coatings was calculated and compared to the respective values of the reference materials. Wear mechanisms were studied by SEM.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7617

Aging temperature and abrasive wear behaviour of cast Al-(4%, 12%, 20%)Si-0.3% Mg alloys

International Nuclear Information System (INIS)

Shah, K.B.; Kumar, Sandeep; Dwivedi, D.K.

2007-01-01

In the present paper, influence of aging temperature during artificial age hardening treatment (T 6 ) of cast Al-(4, 12, 20%)Si-0.3% Mg on abrasive wear behaviour has been reported. Alloys were prepared by controlled melting and casting. Cast alloys were given age hardening treatment having sequence of solutionizing, quenching and artificial aging. All the alloys were solutionized at 510 deg. C for 8 h followed by water quenching (30 deg. C) and aging hardening at 150, 170, 190, 210 and 230 deg. C for 12 h. Abrasive wear tests were conducted against of 320 grade SiC abrasive medium at 5 and 10 N normal loads. It was observed that the silicon content and aging temperature significantly affect the wear resistance. Increase in aging temperature improves the wear resistance. Hypereutectic alloy showed better wear resistance than the eutectic alloy under identical conditions. Optical microstructure study of alloys under investigation has shown that cast dendritic structure is destroyed besides the spheroidization of eutectic silicon crystals after the heat treatment. The extent of change in structure depends on aging temperature. Scanning electron microscopy (SEM) of wear surface was carried to analyze the wear mechanism

Microstructure and High-temperature Wear Behavior of Hot-dipped Aluminized Coating on Different Substrate Materials

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ZHOU De-qin

2018-02-01

Full Text Available The aluminized 45 and H13 steel were prepared via hot-dipped aluminizing and subsequently high-temperature diffusion treatment. The phase, morphology and composition of aluminized coating were characterized by XRD,SEM and EDS methods. Comparative study was performed on unlubricated sliding wear behavior of plating under different substrates on a pin-on-disc wear tester, and the wear mechanism was explored. The results show that the coating is composed of ductile phases FeAl and Fe3Al. Kikendall porosity parallel to the surface exists around the interface of the two phases; because of the carbide particles agglomeration, the bond between the coating and H13 steel is apparently inferior to that in the case of 45 steel; the aluminized 45 steel possesses an excellent wear resistance under 50-200N at 400℃, whereas mild-to-severe wear transition occurs when the temperature increases to 600℃. The wear rate of the aluminized H13 steel reaches the lowest at 400℃, then slightly increases at 600℃. The wear mechanisms of Fe-Al coating are mainly predominated by oxidative mild wear, whereas the extrusion wear prevails in the process for aluminized 45 steel at 600℃.

Application of charged particle activation for testing machine part wear

International Nuclear Information System (INIS)

Kosimova, M.; Tendera, P.

1985-01-01

The results of application of the charge particle activation method to investigate machine part wear are presented. Study of radionuclide activity and yield has been carried out at the U-120M isochronous cyclotron by means of the method of iron foil piles from 20 to 100 μm in thick. Protons and deuterons have been used. Wear measurement is based on determination of wear particle activity in a butyric medium. An example of the results of a bench test of activated piston rings and cylinder liner of the engine for trucks is given. The method of surface activation is shown to be acceptable for studying machine part wear under the regular service conditions, especially on the stage of the primary investigations and development, when sampling structural materials and estimating different lubricating oil applicability

Hardness and wear analysis of Cu/Al2O3 composite for application in EDM electrode

Science.gov (United States)

Hussain, M. Z.; Khan, U.; Jangid, R.; Khan, S.

2018-02-01

Ceramic materials, like Aluminium Oxide (Al2O3), have high mechanical strength, high wear resistance, high temperature resistance and good chemical durability. Powder metallurgy processing is an adaptable method commonly used to fabricate composites because it is a simple method of composite preparation and has high efficiency in dispersing fine ceramic particles. In this research copper and novel material aluminium oxide/copper (Al2O3/Cu) composite has been fabricated for the application of electrode in Electro-Discharge Machine (EDM) using powder metallurgy technique. Al2O3 particles with different weight percentages (0, 1%, 3% and 5%) were reinforced into copper matrix using powder metallurgy technique. The powders were blended and compacted at a load of 100MPa to produce green compacts and sintered at a temperature of 574 °C. The effect of aluminium oxide content on mass density, Rockwell hardness and wear behaviour were investigated. Wear behaviour of the composites was investigated on Die-Sink EDM (Electro-Discharge Machine). It was found that wear rate is highly depending on hardness, mass density and green protective carbonate layer formation at the surface of the composite.

Friction and wear studies of nuclear power plant components in pressurized high temperature water environments

International Nuclear Information System (INIS)

Ko, P.L.; Zbinden, M.; Taponat, M.C.; Robertson, M.F.

1997-01-01

The present paper is part of a series of papers aiming to present the friction and wear results of a collaborative study on nuclear power plant components tested in pressurized high temperature water. The high temperature test facilities and the methodology in presenting the kinetics and wear results are described in detail. The results of the same material combinations obtained from two very different high temperature test facilities (NRCC and EDF) are presented and discussed. (K.A.)

State of art report for high temperature wear test of SMART MCP and CEDM bearing material

International Nuclear Information System (INIS)

Cho, Yong Hu; Lee, Jae Seon; Park, Jin Seok; Kim, Ji Ho; Kim, Jong In

2000-03-01

Wear resistance properties of machine elements has been more critical in view of its significant effect on life extension, economics and material saving because it has been recognized that nearly 80 percent of damages of mechanical elements in the friction pairs are due to the material loss by wear. And wear properties have direct influence on the life of a machine in a great extend under extremely severe operating condition. Therefore highly improved wear properties of machine elements operating in such circumstances is heavily required. The purpose of this report is to survey current technology for high temperature wear test in order to establish the test plan for the life evaluation of SMART MCP and CEDM bearing materials. Friction and wear test will be done under high pressure (170 MPa) and high temperature (350 degree C) with water as lubricant to simulate the operating condition of the nuclear power reactor. Because pump type for MCP is selected as the caned motor pump which needs no mechanical sealing, the rotating shaft on which bearing is fully submerged by main coolant with high temperature. So MCP bearing operates without additional lubricant. CEDM is adopted as the ball-screw type with fine controllability. So the driving part is designed as the immersed-in type by main coolant. Therefore the anti-wear and reliability of driving parts are much consequent to guarantee the lifetime and the safety of the whole system. Tribometer adapted to high temperature and pressure circumstance is needed to execute bearing material testing. Test parameters are material, sliding speed, sliding distance and applied load. In order to identify the wear mechanism, optical microscope and surface roughness testers are required. The result of this report will provide an elementary data to develop bearing materials and to estimate bearing lifetime for the bearings of MCP and CEDM in SMART. (author)

High Temperature Sliding Wear of NiAl-based Coatings Reinforced by Borides

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Oleksandr UMANSKYI

2016-05-01

Full Text Available The development of composite materials (CM in the systems “metal-refractory compound” is one of the up-to-date trends in design of novel materials aimed at operating under the conditions of significant loads at high temperature. To design such material, NiAl, which is widely used for deposition of protective coatings on parts of gas-turbine engines, was selected for a matrix. To strengthen a NiAl under the conditions of intense wear and a broad temperature range (up to 1000 °C, it is reasonable to add refractory inclusions. Introduction of refractory borides into matrix leads to a marked increase in metal wear resistance. In order to research the behavior of the designed composites at high temperatures and to study the influence of oxides on the friction processes, the authors carried out high temperature oxidation of CM of the above systems at 1000 °С for 90 min. It was determined that all of the composites were oxidized selectively and that the thickness of oxide layers formed on the boride inclusions is 3 – 7 times that on the oxides formed on the NiAl matrix. The mechanism of wear of gas-thermal coatings of the NiAl – МеB2 systems was studied for conditions of high temperature tribotests using the «pin-on-disc» technique. The obtained results indicate that introduction of TiB2, CrB2 and ZrB2 leads to their more intense oxidation during high temperature tribotests as compared to the matrix. The oxides formed on refractory borides act as solid lubricants, which promote a decrease in wear of the contact friction pairs. For more detailed investigation of the effect of tribo-oxidation products on the friction processes, tribotests were conducted for prior oxidized (at 900 °С coatings NiAl – 15 wt.% CrB2 (TiB2, ZrB2.DOI: http://dx.doi.org/10.5755/j01.ms.22.1.8093

The unlubricated reciprocating sliding wear of 316 stainless steel in C02 in the temperature range 20 to 6000C

International Nuclear Information System (INIS)

Smith, A.F.

1985-11-01

The friction and wear behaviour of 316 stainless steel in C0 2 has been investigated in the load range 8 - 5ON from 20 to 600 0 C. Wear transitions occurred at all temperatures but were load dependent. At and below 300 0 C wear transitions only took place at low leads whereas above 300 0 C transitions were seen al all loads. The low temperature wear transition, giving an order of magnitude decrease in wear rate was associated with a change in friction behaviour. The friction force across the specimen was initially widely fluctuating and varied from cycle to cycle. After a time, which did not necessarily coincide with the wear transition the cyclic variation in the friction force become much less. This smoother sliding is thought to indicate a trend to oxide -oxide contacts. At higher temperatures wear transitions result in a two orders of magnitude reduction in wear. The corresponding friction transition was similar to the low temperature friction change but also included a marked temporary drop in the coefficient of friction. (author)

Study on microstructure and high temperature wear resistance of laser cladded nuclear valve clack

International Nuclear Information System (INIS)

Zhang Chunliang; Chen Zichen

2002-01-01

Laser cladding of Co-base alloy on the nuclear valve-sealing surface are performed with a 5 kW CO 2 transverse flowing laser. The microstructure and the high temperature impact-slide wear resistance of the laser cladded coating and the plasma cladded coating are studied. The results show that the microstructure, the dilution rate and the high temperature impact-slide wear resistance of the laser cladded coating have obvious advantages over the spurt cladding processing

Thermodynamical Description of Running Discontinuities: Application to Friction and Wear

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Claude Stolz

2010-06-01

Full Text Available The friction and wear phenomena appear due to contact and relative motion between two solids. The evolution of contact conditions depends on loading conditions and mechanical behaviours. The wear phenomena are essentially characterized by a matter loss. Wear and friction are in interaction due to the fact that particles are detached from the solids. A complex medium appears as an interface having a strong effect on the friction condition. The purpose of this paper is to describe such phenomena taking account of different scales of modelization in order to derive some macroscopic laws. A thermodynamical approach is proposed and models of wear are analysed in this framework where the separation between the dissipation due to friction and that due to wear is made. Applications on different cases are presented.

The Applicability of Taylor’s Model to the Drilling of CFRP Using Uncoated WC-Co Tools: The Influence of Cutting Speed on Tool Wear

OpenAIRE

Merino Perez, J.L.; Merson, E.; Ayvar-Soberanis, S.; Hodzic, A.

2014-01-01

This work investigates the applicability of Taylor’s model on the drilling of CFRP using uncoated WC-Co tools, by assessing the influence of cutting speed (Vc) on tool wear. Two different resins, possessing low and high glass transition temperatures (Tg), and two different reinforcements, high strength and high modulus woven fabrics, were combined into three different systems. Flank wear rate gradient exhibited to be more reinforcement dependent, while the actual flank wear rate showed to be ...

Influence of Sintering Temperature on Hardness and Wear Properties of TiN Nano Reinforced SAF 2205

Science.gov (United States)

Oke, S. R.; Ige, O. O.; E Falodun, O.; Obadele, B. A.; Mphalele, M. R.; Olubambi, P. A.

2017-12-01

Conventional duplex stainless steel degrade in wear and mechanical properties at high temperature. Attempts have been made by researchers to solve this problems leading to the dispersion of second phase particles into duplex matrix. Powder metallurgy methods have been used to fabricate dispersion strengthened steels with a challenge of obtaining fully dense composite and grain growth. This could be resolved by appropriate selection of sintering parameters especially temperature. In this research, spark plasma sintering was utilized to fabricate nanostructured duplex stainless steel grade SAF 2205 with 5 wt.% nano TiN addition at different temperatures ranging from 1000 °C to 1200 °C. The effect of sintering temperature on the microstructure, density, hardness and wear of the samples was investigated. The results showed that the densities and grain sizes of the sintered nanocomposites increased with increasing the sintering temperature. The microstructures reveal ferrite and austenite grains with fine precipitates within the ferrite grains. The study of the hardness and wear behaviors, of the samples indicated that the optimum properties were obtained for the sintering temperature of 1150 °C.

Insulated skin temperature as a measure of core body temperature for individuals wearing CBRN protective clothing

International Nuclear Information System (INIS)

Richmond, V L; Wilkinson, D M; Blacker, S D; Horner, F E; Carter, J; Rayson, M P; Havenith, G

2013-01-01

This study assessed the validity of insulated skin temperature (T is ) to predict rectal temperature (T re ) for use as a non-invasive measurement of thermal strain to reduce the risk of heat illness for emergency service personnel. Volunteers from the Police, Fire and Rescue, and Ambulance Services performed role-related tasks in hot (30 °C) and neutral (18 °C) conditions, wearing service specific personal protective equipment. Insulated skin temperature and micro climate temperature (T mc ) predicted T re with an adjusted r 2 = 0.87 and standard error of the estimate (SEE) of 0.19 °C. A bootstrap validation of the equation resulted in an adjusted r 2 = 0.85 and SEE = 0.20 °C. Taking into account the 0.20 °C error, the prediction of T re resulted in a sensitivity and specificity of 100% and 91%, respectively. Insulated skin temperature and T mc can be used in a model to predict T re in emergency service personnel wearing CBRN protective clothing with an SEE of 0.2 °C. However, the model is only valid for T is over 36.5 °C, above which thermal stability is reached between the core and the skin. (paper)

EFFECT OF THE TEMPERATURE ON THE FRICTION AND WEAR PROPERTIES OF BULK AMORPHOUS ALLOY

OpenAIRE

DAWIT ZENEBE SEGU; PYUNG HWANG; SEOCK-SAM KIM

2014-01-01

The present paper report the results of an experimental investigation of the temperature effect on the sliding friction and wear properties of the bulk metallic glass (BMG). To improve the friction and wear properties of the BMG, the disk specimens were developed in the alloy system of Fe67.6C7.1Si3.3B5.5P8.7Cr2.3Mo2.6Al2Co1.0 using hot metal and industrial ferro-alloys. The friction and wear test was performed using flat-on-flat contact configuration of unidirectional tribometer and Si3N4 ce...

Bio-inspired polymeric patterns with enhanced wear durability for microsystem applications

International Nuclear Information System (INIS)

Singh, R. Arvind; Siyuan, L.; Satyanarayana, N.; Kustandi, T.S.; Sinha, Sujeet K.

2011-01-01

At micro/nano-scale, friction force dominates at the interface between bodies moving in relative motion and severely affects their smooth operation. This effect limits the performance of microsystem devices such as micro-electro-mechanical systems (MEMS). In addition, friction force also leads to material removal or wear and thereby reduces the durability i.e. the useful operating life of the devices. In this work, we fabricated bio-inspired polymeric patterns for tribological applications. Inspired by the surface features on lotus leaves namely, the protuberances and wax, SU-8 polymeric films spin-coated on silicon wafers were topographically and chemically modified. For topographical modification, micro-scale patterns were fabricated using nanoimprint lithography and for chemical modification, the micro-patterns were coated with perfluoropolyether nanolubricant. Tribological investigation of the bio-inspired patterns revealed that the friction coefficients reduced significantly and the wear durability increased by several orders. In order to enhance the wear durability much further, the micro-patterns were exposed to argon/oxygen plasma and were subsequently coated with the perfluoropolyether nanolubricant. Bio-inspired patterns with enhanced wear durability, such as the ones investigated in the current work, have potential tribological applications in MEMS/Bio-MEMS actuator-based devices. Highlights: →Bio-inspired polymeric patterns for tribological applications in microsystems. →Novel surface modification for the patterns to enhance tribological properties. →Patterns show low friction properties and extremely high wear durability.

The role of hardness and microstructure in high temperature pitting in the impact wear of 9Cr boiler material. Part 1

International Nuclear Information System (INIS)

Morri, J.

1987-11-01

This report describes impact wear experiments on 9Cr1Mo finned boiler tube specimens in 3 different heat treated forms. The objective of the tests was to establish whether a high temperature, high wear rate, pitting form of wear was dependent upon the residual microstructure and hardness. Although a x2 reduction in specific wear rate was achieved for the martensitic structure, the pitting characteristic remained. It is concluded that modifying the as-received 9Cr microstructure has not suppressed the high temperature severe form of wear. (author)

Effects of sintering temperature on the microstructural evolution and wear behavior of WCp reinforced Ni-based coatings

Science.gov (United States)

Chen, Chuan-hui; Bai, Yang; Ye, Xu-chu

2014-12-01

This article focuses on the microstructural evolution and wear behavior of 50wt%WC reinforced Ni-based composites prepared onto 304 stainless steel substrates by vacuum sintering at different sintering temperatures. The microstructure and chemical composition of the coatings were investigated by X-ray diffraction (XRD), differential thermal analysis (DTA), scanning and transmission electron microscopy (SEM and TEM) equipped with energy-dispersive X-ray spectroscopy (EDS). The wear resistance of the coatings was tested by thrust washer testing. The mechanisms of the decomposition, dissolution, and precipitation of primary carbides, and their influences on the wear resistance have been discussed. The results indicate that the coating sintered at 1175°C is composed of fine WC particles, coarse M6C (M=Ni, Fe, Co, etc.) carbides, and discrete borides dispersed in solid solution. Upon increasing the sintering temperature to 1225°C, the microstructure reveals few incompletely dissolved WC particles trapped in larger M6C, Cr-rich lamellar M23C6, and M3C2 in the austenite matrix. M23C6 and M3C2 precipitates are formed in both the γ/M6C grain boundary and the matrix. These large-sized and lamellar brittle phases tend to weaken the wear resistance of the composite coatings. The wear behavior is controlled simultaneously by both abrasive wear and adhesive wear. Among them, abrasive wear plays a major role in the wear process of the coating sintered at 1175°C, while the effect of adhesive wear is predominant in the coating sintered at 1225°C.

Protection of 310l Stainless Steel from Wear at Elevated Temperatures using Conicraly Thermal Spray Coatings with and without Sic Addition

Science.gov (United States)

Zhang, Yan; Zhang, Tao; Li, Kaiyang; Li, Dongyang

2017-10-01

Due to its high oxidation resistance, 310L stainless steel is often used for thermal facilities working at high-temperatures. However, the steel may fail prematurely at elevated temperatures when encounter surface mechanical attacks such as wear. Thermal spray coatings have been demonstrated to be effective in protecting the steel from wear at elevated temperatures. In this study, we investigated the effectiveness of high velocity oxy-fuel(HVOF) spraying CoNiCrAlY/SiC coatings in resisting wear of 310L stainless steel at elevated temperature using a pin-on-disc wear tester. In order to further improve the performance of the coating, 5%SiC was added to the coating. It was demonstrated that the CoNiCrAlY/SiC coating after heat treatment markedly suppressed wear. However, the added SiC particles did not show benefits to the wear resistance of the coating. Microstructures of CoNiCrAlY coatings with and without the SiC addition were characterized in order to understand the mechanism responsible for the observed phenomena.

Metal nitride coatings by physical vapor deposition (PVD) for a wear resistant aluminum extrusion die.

Science.gov (United States)

Lee, Su Young; Kim, Sang Ho

2014-12-01

The purpose of this study is to investigate the friction and wear behaviors of CrN, TiN, CrAlN, and TiAIN coated onto SKD61 for application to Al 7000 series extrusion dies. On the wear test, the experimental parameters are the load and the counter material's temperature. The results showed that the friction coefficient increased with load but decreased with the counter material's temperature, and the friction coefficients of CrN and CrAIN were lower than the friction coefficients of TiAIN and TIN, especially at a higher temperature. The wear track with different coatings identified different wear behaviors; the wear behavior of CrAIN was found to be abrasive, but the wear behavior of TiN, CrN, and TiAIN was adhesive. Therefore, CrAIN showed the least wear loss with a lower friction coefficient and less adhesion with counter materials at the highest range of wear load and temperature. This resulted in the easy formation of aluminum oxide in the wear track and less Al adhesion; moreover during the hard second phase, AIN dispersed in the film during deposition.

Elaboration of high-temperature friction polymer material and study of its wear aspects

International Nuclear Information System (INIS)

Gventsadze, L.

2009-01-01

High-temperature friction composite material is elaborated and its physical, mechanical and tribologic features are studied. It is shown, that addition to the friction material composition of filling material having nanopores -diatomite-and its modification with polyethilensilan leads to friction materials friction coefficient stability and wear resistance increase at high temperatures (400-600 ℃). (author)

Influence of the ion nitriding temperature in the wear resistance of AISI H13 tool steel

International Nuclear Information System (INIS)

Heck, Stenio Cristaldo; Fernandes, Frederico Augusto Pires; Pereira, Ricardo Gomes; Casteletti, Luiz Carlos; Totten, George Edward

2010-01-01

The AISI H13 tool steel for hot work is the most used in its category. This steel was developed for injection molds and extrusion of hot metals as well as for conformation in hot presses and hammers. Plasma nitriding can improve significantly the surface properties of these steels, but the treatments conditions, such as temperature, must be optimized. In this work the influence of nitriding treatment temperature on the wear behavior of this steel is investigated. Samples of AISI H13 steel were quenched and tempered and then ion nitrided in the temperatures of 450, 550 and 650 deg C, at 4mbar pressure, during 5 hours. Samples of the treated material were characterized by optical microscopy, Vickers microhardness, x-ray analysis and wear tests. Plasma nitriding formed hard diffusion zones in all the treated samples. White layers were formed in samples treated at 550 deg C and 650 deg C. The treatment temperature of 450 deg C produced the highest hardness. Treatment temperature showed great influence in the diffusion layer thickness. X-ray analysis indicated the formation of the Fe_3N, Fe_4N and CrN phases for all temperatures, but with different concentrations. Nitriding increased significantly the AISI H13 wear resistance. (author)

Effect of sintering temperature and boron carbide content on the wear behavior of hot pressed diamond cutting segments

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Islak S.

2015-01-01

Full Text Available The aim of this study was to investigate the effect of sintering temperature and boron carbide content on wear behavior of diamond cutting segments. For this purpose, the segments contained 2, 5 and 10 wt.% B4C were prepared by hot pressing process carried out under a pressure of 35 MPa, at 600, 650 and 700 °C for 3 minutes. The transverse rupture strength (TRS of the segments was assessed using a three-point bending test. Ankara andesite stone was cut to examine the wear behavior of segments with boron carbide. Microstructure, surfaces of wear and fracture of segments were determined by scanning electron microscopy (SEM-EDS, and X-ray diffraction (XRD analysis. As a result, the wear rate decreased significantly in the 0-5 wt.% B4C contents, while it increased in the 5-10 wt.% B4C contents. With increase in sintering temperature, the wear rate decreased due to the hard matrix.

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.

Wear resistance of polypropylene-SiC composite

International Nuclear Information System (INIS)

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

2017-01-01

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. (paper)

Wear-resistant ball bearings for space applications

Science.gov (United States)

Boving, H.; Hintermann, H. E.; Hanni, W.; Bondivenne, E.; Boeto, M.; Conde, E.

1977-01-01

Ball bearings consisting of steel parts of which the rings are coated with hard, wear resistant, chemical vapor deposited TiC are described. Experiments conducted in ultrahigh vacuum, using cages of various materials with self-lubricating properties, show that such bearings are suitable for space applications. The results of laboratory tests on the ESA Meteosat Radiometer Focalizing mechanism, which contains six coated bearings, are summarized.

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

International Nuclear Information System (INIS)

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

2012-01-01

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

Micro-Structures and High-Temperature Friction-Wear Performances of Laser Cladded Cr–Ni Coatings

Directory of Open Access Journals (Sweden)

Li Jiahong

2018-01-01

Full Text Available Cr–Ni coatings with the mass ratios of 17% Cr–83% Ni, 20% Cr–80% Ni and 24% Cr–76% Ni were fabricated on H13 hot work mould steel using a laser cladding (LC. The surface–interface morphologies, chemical elements, surface roughness and phase composition of the obtained Cr–Ni coatings were analysed using a scanning electron microscope (SEM, energy disperse spectroscopy (EDS, atomic force microscope (AFM and X–ray diffractometer (XRD, respectively. The friction–wear properties and wear rates of Cr–Ni coatings with the different mass ratios of Cr and Ni at 600 °C were investigated, and the worn morphologies and wear mechanism of Cr–Ni coatings were analysed. The results show that the phases of Cr–Ni coatings with mass ratios of 17% Cr–83% Ni, 20% Cr–80% Ni and 24% Cr–76% Ni are composed of Cr + Ni single-phases and their compounds at the different stoichiometry, the porosities on the Cr–Ni coatings increase with the Cr content increasing. The average coefficient of friction (COF of 17% Cr–83% Ni, 20% Cr–80% Ni and 24% Cr–76% coatings are 1.10, 0.33 and 0.87, respectively, in which the average COF of 20% Cr–80% Ni coating is the lowest, exhibiting the better anti-friction performance. The wear rate of 17% Cr–83% Ni, 20% Cr–80% Ni and 24% Cr–76% Ni coatings is 4.533 × 10−6, 5.433 × 10−6, and 1.761 × 10−6 N−1·s−1, respectively, showing the wear resistance of Cr–Ni coatings at a high temperature increases with the Cr content, in which the wear rate is 24% Cr–76% Ni coating with the better reducing wear. The wear mechanism of 17% Cr–83% Ni and 20% Cr–80% Ni and 24% Cr–76% coatings at 600 °C is primarily adhesive wear, and that of 24% Cr–76% coating is also accompanied by oxidative wear.

Application of RNB for high sensitive wear diagnostics in medicine technique and industry

International Nuclear Information System (INIS)

Fehsenfeld, P.; Eifrig, C.; Kubat, R.

2002-01-01

The RTM--Radionuclide Technique in Mechanical engineering--is now extended to the solution of world wide problems in medicine technique (prosthetics), and in development of modern materials (synthetic materials, ceramics, hard coatings, etc.) and their industrial application. RNB--Radioactive Nuclear Beams of 7 Be or 22 Na--may enable the required extreme thin radioactive surface labeling (several micrometers) of synthetic materials for wear measurements without producing radiation damages of influence to the wear properties of the material. The function principle and special properties of the RTM on-line wear diagnostics and its components, the measurement methods, the radioactive surface labeling, and the measurement instruments are explained. The quality features of a 7 Be and 22 Na-beam for RTM application are specified

Wear behaviour of nitrogen-implanted and nitrided Ti-6Al-4V alloy

International Nuclear Information System (INIS)

Martinella, R.; Giovanardi, S.; Chevallard, G.; Villani, M.; Molinari, A.; Tosello, C.

1985-01-01

The comparison between the wear behaviour of nitrogen-implanted Ti-6Al-4V alloy and that of nitrided Ti-6Al-4V alloy is reported. Both treatments were carried out at temperatures from 573 to 973 K on lapped surfaces; in order to compare roughness effects, nitriding was also carried out on rougher samples. An improvement in wear resistance for lapped surfaces was noted after implantation at 573 K or higher temperatures and after nitriding at temperatures over 773 K only; however, at 873 K, nitriding was more effective than implantation. Rough nitrided surfaces showed better wear resistance than lapped nitrided surfaces or lapped implanted surfaces. Most probably the improvement in wear resistance on implanted samples is due to a reduction in friction induced by chemical modification of the surface as a result of oxide and TiN. Scanning electron microscopy observations which show subsurface voids and coalescence are in good agreement with a wear model previously reported. As implantation preserves the surface finish, a possible application is suggested. (Auth.)

Application of radioactive isotopes in the field of investigations of the means of transportation wear

International Nuclear Information System (INIS)

Gromann, Kh-D.

1979-01-01

The Station for governing of isotope technique ensures application of radioactive isotopes in the transport of the GDR. The main directions of the isotope application are investigations of wear and leaks. It is reported about the wear investigations performed on models and real structural elements at laboratory testing stands as well as on the real structural elements in the exploitation conditions. Special attention should be paid to the numerous measurements of wear of engines, rails and so on. Data and valuable results have been obtained about the problem of the short-term wear measurement. Measurements of leaks by means of radioactive isotopes application is used for investigations of the hermeticy of the refrigerator tronsport means, heating systems and clymatizing installations of the carriges as well as stationary installations. Then, measurements have been done of leaks in pipelines as well as determinations of their lacalization and intensity. General and specific advantages of separate methods are discussed [ru

Sliding wear studies of sprayed chromium carbide-nichrome coatings for gas-cooled reactor applications

International Nuclear Information System (INIS)

Li, C.C.; Lai, G.Y.

1978-09-01

Chromium carbide-nichrome coatings being considered for wear protection of some critical components in high-temperature gas-cooled reactors (HTGR's) were investigated. The coatings were deposited either by the detonation gun or the plasma-arc process. Sliding wear tests were conducted on specimens in a button-on-plate arrangement with sliding velocities of 7.1 x 10 -3 and 7.9 mm/s at 816 0 C in a helium environment simulates HTGR primary coolant chemistry. The coatings containing 75 or 80 wt % chromium carbide exhibited excellent wear resistance. As the chromium carbide content decreased from either 80 or 75 to 55 wt %, with a concurrent decrease in coating hardness, wear-resistance deteriorated. The friction and wear behavior of the soft coating was similar to that of the bare metal--showing severe galling and significant amounts of wear debris. The friction characteristics of the hard coating exhibited a strong velocity dependence with high friction coefficients in low sliding velocity tests ad vice versa. Both the soft coating and bare metal showed no dependence on sliding velocity. The wear behavior observed in this study is of adhesive type, and the wear damage is believed to be controlled primarily by the delamination process

Effect of Volume Fraction of Particle on Wear Resistance of Al2O3/Steel Composites at Elevated Temperature

Institute of Scientific and Technical Information of China (English)

BAO Chong-gao; WANG En-ze; GAO Yi-min; XING Jian-dong

2005-01-01

Based on previous work,abrasive wear resistance of Al2 O3/steel composites with different Al2 O3 parti cle volume fraction (VOF) at 900 C was investigated.The experimental results showed that a suitable particle VOF is important to protect the metal matrix from wear at elevated temperature.Both too high and too low particle VOF lead to a poor abrasive wear because a bulk matrix is easily worn off by grits when it exceeds the suitable VOF and also because when VOF is low,the Al2O3 particles are easily dug out by grits during wearing as well.When the particle VOF is 39%,the wear resistance of tested composites is excellent.

A novel nonlinear nano-scale wear law for metallic brake pads.

Science.gov (United States)

Patil, Sandeep P; Chilakamarri, Sri Harsha; Markert, Bernd

2018-05-03

In the present work, molecular dynamics simulations were carried out to investigate the temperature distribution as well as the fundamental friction characteristics such as the coefficient of friction and wear in a disc-pad braking system. A wide range of constant velocity loadings was applied on metallic brake pads made of aluminium, copper and iron with different rotating speeds of a diamond-like carbon brake disc. The average temperature of Newtonian atoms and the coefficient of friction of the brake pad were investigated. The resulting relationship of the average temperature with the speed of the disc as well as the applied loading velocity can be described by power laws. The quantitative description of the volume lost from the brake pads was investigated, and it was found that the volume lost increases linearly with the sliding distance. Our results show that Archard's linear wear law is not applicable to a wide range of normal loads, e.g., in cases of low normal load where the wear rate was increased considerably and in cases of high load where there was a possibility of severe wear. In this work, a new formula for the brake pad wear in a disc brake assembly is proposed, which displays a power law relationship between the lost volume of the metallic brake pads per unit sliding distance and the applied normal load with an exponent of 0.62 ± 0.02. This work provides new insights into the fundamental understanding of the wear mechanism at the nano-scale leading to a new bottom-up wear law for metallic brake pads.

Tribopolymerization as an anti-wear mechanism. Quarterly progress report

Energy Technology Data Exchange (ETDEWEB)

Furey, M.J.

1996-04-01

The primary objective of this activity is to obtain the necessary data which would enhance, promote, and encourage the introduction of advanced lubrication technology into the marketplace. This includes (a) defining specific but different applications, (b) establishing the limits or ranges of applied loads, speeds, and temperatures over which the concept of tribopolymerization would work in reducing wear and/or friction, (c) continuing in efforts to understand the film-forming process (this rates to (b) above), using this knowledge to develop new and even more effective additives, and (d) exploring possible connections with private and investment companies for the licensing and marketing of products which will reduce friction and wear in a variety of applications. Progress was made in several different but connected areas. These included (a) establishing of load/velocity limits of selected monomers for ceramic lubrication, (b) the discovery of new and effective monomers designed for higher temperature anti-wear applications, (c) improvements and modifications of the high load/high speed pin-on-disk machine, (d) the initiation of related or spin-off projects designed to get their advanced technology into the marketplace, (e) the filing of three new patent applications, and (f) collaborative research with Dr. Kajdas--the co-inventor with Dr. Furey--on tribopolymerization as a novel and effective approach to the boundary lubrication of ceramics and steel. These and other elements of progress made during the first Quarter of 1996 are discussed briefly.

The influence of elevated temperature transformation and mechanical properties of a precipitation hardening martensitic stainless steel on its wear behaviour

International Nuclear Information System (INIS)

Smith, A.F.

1989-11-01

Self wear tests of a martensitic stainless steel in CO 2 in the temperature range 20-300degC showed transitional behaviour at 20 and 300degC. In the mid temperature range a severe wear rate of ∼ 2 x 10 -13 m 3 /Nm persisted for sliding distances up to 2000 m. A possible explanation was that while strain induced transformation of retained austenite at low temperatures provided a sufficiently hardened substrate that allowed inelastic rather than plastic interactions this did not occur at 200degC. Tests were carried out to determine the temperature above which strain no longer transformed austenite into martensite. Although a martensite start temperature of ∼ 150degC was found for the present steel the presence of only ∼ 10% retained austenite in the ''as heat treated'' material suggests that its transformation to martensite at 200degC would not materially affect the extent of subsurface hardening. It is proposed that a surface reaction plays a role in transition behaviour. At 300degC the reaction product is an oxide but at room temperature it is possibly a carbonate. The stability of the carbonate decreases with temperature thus giving an intermediate temperature range where metal/metal contacts prevail leading to the persistent high wear behaviour. (author)

Prediction Of Abrasive And Diffusive Tool Wear Mechanisms In Machining

Science.gov (United States)

Rizzuti, S.; Umbrello, D.

2011-01-01

Tool wear prediction is regarded as very important task in order to maximize tool performance, minimize cutting costs and improve the quality of workpiece in cutting. In this research work, an experimental campaign was carried out at the varying of cutting conditions with the aim to measure both crater and flank tool wear, during machining of an AISI 1045 with an uncoated carbide tool P40. Parallel a FEM-based analysis was developed in order to study the tool wear mechanisms, taking also into account the influence of the cutting conditions and the temperature reached on the tool surfaces. The results show that, when the temperature of the tool rake surface is lower than the activation temperature of the diffusive phenomenon, the wear rate can be estimated applying an abrasive model. In contrast, in the tool area where the temperature is higher than the diffusive activation temperature, the wear rate can be evaluated applying a diffusive model. Finally, for a temperature ranges within the above cited values an adopted abrasive-diffusive wear model furnished the possibility to correctly evaluate the tool wear phenomena.

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

Fretting wear behaviour of TiC/Ti(C,N)/TiN multi-layer coatings at elevated temperature in gross slip regime

International Nuclear Information System (INIS)

Liu Hanwei; Huang Kunpeng; Zhu Minhao; Zhou Zhongrong

2005-01-01

Tic/Ti(C,N)/TiN multi-layer coatings are prepared on the 1Cr13 stainless steel substrate by the technique of Chemical Vapour Deposition, and the fretting wear behaviour of 1Cr13 stainless steel and TiC/Ti(C,N)/TiN coatings are investigated and studied controversially from 25 degree C to 400 degree C in the gross slip regime. It shows that the temperature has great influence on the fretting wear in the gross slip regime for the 1Cr13 stainless steel but little for Ti/C/Ti(C,N)/TiN multi-layer coatings. With the temperature increasing, the friction coefficient and the wear volume of the 1Cr13 alloy decreases and the wear volume of TiC/Ti(C, N)/TiN multi-layer coatings is invariant. TiC/Ti(C,N)/TiN multi-layer coatings have better wear-resistant capability than the 1Cr13 stainless steel, but the wear volume of the substrate increases greatly because of the grain-abrasion resulted from hard debris when TiC/Ti(C,N)/TiN multi-layer coatings are ground off. (authors)

Predicting railway wheel wear under uncertainty of wear coefficient, using universal kriging

International Nuclear Information System (INIS)

Cremona, Marzia A.; Liu, Binbin; Hu, Yang; Bruni, Stefano; Lewis, Roger

2016-01-01

Railway wheel wear prediction is essential for reliability and optimal maintenance strategies of railway systems. Indeed, an accurate wear prediction can have both economic and safety implications. In this paper we propose a novel methodology, based on Archard's equation and a local contact model, to forecast the volume of material worn and the corresponding wheel remaining useful life (RUL). A universal kriging estimate of the wear coefficient is embedded in our method. Exploiting the dependence of wear coefficient measurements with similar contact pressure and sliding speed, we construct a continuous wear coefficient map that proves to be more informative than the ones currently available in the literature. Moreover, this approach leads to an uncertainty analysis on the wear coefficient. As a consequence, we are able to construct wear prediction intervals that provide reasonable guidelines in practice. - Highlights: • Wear prediction is of outmost importance for reliability of railway systems. • Wear coefficient is essential in prediction through Archard's equation. • A novel methodology is developed to predict wear and RUL. • Universal kriging is used for wear coefficient and uncertainty estimation. • A simulation study and a real case application are provided.

Abrasive wear of intermetallics

International Nuclear Information System (INIS)

Hawk, J.A.; Alman, D.E.; Wilson, R.D.

1995-01-01

The US Bureau of Mines is investigating the wear behavior of a variety of advanced materials. Among the many materials under evaluation are intermetallic alloys based on the compounds: Fe 3 Al, Ti 3 Al, TiAl, Al 3 Ti, NiAl and MoSi 2 . The high hardness, high modulus, low density, and superior environmental stability of these compounds make them attractive for wear materials. This paper reports on the abrasive wear of alloys and composites based on the above compounds. The abrasive wear behavior of these alloys and composites are compared to other engineering materials used in wear applications

Development of in-situ ZrC reinforced iron based composites for wear resistance applications

International Nuclear Information System (INIS)

Bandyopadhyay, T.K.; Das, K.

2002-01-01

A common objective behind the processing of iron-based composites is to improve the wear resistance of steels by incorporating some reinforcing phases, e.g., carbides and oxides. In the present investigation, iron-based zirconium carbide reinforced composite is produced by the aluminothermic reduction of zircon sand (ZrSiO 4 ) and blue dust (Fe 2 O 3 ) in the presence of carbon. Aluminothermic reduction of blue dust and zircon sand, being highly exothermic in nature, essentially leads to a self-propagating high-temperature synthesis (SHS) of the Fe-ZrC composite. The as-cast composite is characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mechanical properties of the composite and the effect of heat treatment on the microstructure are evaluated. The composite possess sufficient hardness and promising abrasive wear resistance property. The abrasive wear resistance property of the Fe-ZrC composite is compared with that of a M2 grade tool material and it is found to be better than the tool material. The composite also possess good high temperature stability. (author)

A new methodology for predictive tool wear

Science.gov (United States)

Kim, Won-Sik

An empirical approach to tool wear, which requires a series of machining tests for each combination of insert and work material, has been a standard practice for industries since early part of the twentieth century. With many varieties of inserts and work materials available for machining, the empirical approach is too experiment-intensive that the demand for the development of a model-based approach is increasing. With a model-based approach, the developed wear equation can be extended without additional machining experiments. The main idea is that the temperatures on the primary wear areas are increasing such that the physical properties of the tool material degrade substantially and consequently tool wear increases. Dissolution and abrasion are identified to be the main mechanisms for tool wear. Flank wear is predominantly a phenomenon of abrasion as evident by the presence of a scoring mark on the flank surface. Based on this statement, it is reasonable to expect that the flank-wear rate would increase with the content of hard inclusions. However, experimental flank wear results did not necessary correspond to the content of cementite phase present in the steels. Hence, other phenomena are believed to significantly affect wear behavior under certain conditions. When the cutting temperature in the flank interface is subjected to high enough temperatures, pearlitic structure austenizes. During the formation of a new austenitic phase, the existing carbon is dissolved into the ferrite matrix, which will reduce the abrasive action. To verify the austenitic transformation, turning tests were conducted with plain carbon steels. The machined surface areas are imaged using X-ray diffraction the Scanning Electron Microscope (SEM) and the Transmission Electron Microscope (TEM). On the other hand, crater wear occurs as a result of dissolution wear and abrasive wear. To verify the wear mechanisms of crater wear, various coating inserts as well as uncoated inserts were

Nitrogen plasma immersion ion implantation for surface treatment and wear protection of austenitic stainless steel X6CrNiTi1810

International Nuclear Information System (INIS)

Blawert, C.; Mordike, B.L.

1999-01-01

Plasma immersion ion implantation is an effective surface treatment for stainless steels. The influence of treatment parameters (temperature, plasma density and pressure) on the sliding wear resistance are studied here. At moderate temperatures, nitrogen remains in solid solution without forming nitrides. This increases the surface hardness and the wear resistance without affecting the passivation of the steel. This may allow the use of such steels in applications where their poor wear resistance would normally prohibit their use. (orig.)

Assessment of thermal spray coatings for wear and abrasion resistance applications

Science.gov (United States)

Karode, Ishaan Nitin

Thermal spray cermet and metallic coatings are extensively used for wear, abrasion and corrosion control in a variety of industries. The first part of the thesis focuses mainly on testing of sand erosion resistance of thermal spray coatings on carbon composites used in the manufacture of helicopter rotor blades. The test set-up employed is a sand blasting machine and is an effort to duplicate the in-flight conditions especially those encountered in hot arid conditions. The technique adopted follows the Department of Defence test method standard. Carbon Composites have excellent stiffness, strength and low weight/density. The strength to weight ratio is high. Hence, these are used in aerospace applications to a large extent. However, the biggest problem encountered with carbon composites is its low abrasion resistance as its surface is very weak. Hence, thermal spray coatings are used to improve the surface properties of CFRP. Zinc bond coats and WC-Co coatings were tested. However, high amount of thermal stresses were developed between the substrate and the coating due to large differences in the CTE's of the both, leading to high mass losses within two minutes and just 130 grams of sand sprayed on to the coatings with the sand blasting machine built; and hence the coatings with CC as a substrate could not qualify for the application. The second part of the thesis focuses on the assessment of different thermal spray coatings used for manufacture of mechanical seals in pumps and analyze the best coating material for the wear resistance application through detail quantification of material loss by block-on-ring test set-up. A machine based on Block-on-ring test set-up following ASTM G77 (Measurement of Adhesive wear resistance of thermal spray coatings) standards was built to duplicate the pump conditions. Thermally sprayed coated materials were tested in different conditions (Load, time, abrasive). WC-Co had the highest wear resistance (lower volume losses) and

Steam generator fretting-wear damage: A summary of recent findings

International Nuclear Information System (INIS)

Guerout, F.M.; Fisher, N.J.

1999-01-01

Flow-induced vibration of steam generator (SG) tubes may sometimes result in fretting-wear damage at the tube-to-support locations. Fretting-wear damage predictions are largely based on experimental data obtained at representative test conditions. Fretting-wear of SG materials has been studied at the Chalk River Laboratories for two decades. Tests are conducted in fretting-wear test machines that simulate SG environmental conditions and tube-to-support dynamic interactions. A new high-temperature force and displacement measuring system was developed to monitor tube-to-support interaction (i.e., work-rate) at operating conditions. This improvement in experimental fretting-wear technology was used to perform a comprehensive study of the effect of various environment and design parameters on SG tube wear damage. This paper summarizes the results of tests performed over the past 4 yr to study the effect of temperature, water chemistry, support geometry, and tube material on fretting-wear. The results show a significant effect of temperature on tube wear damage. Therefore, fretting-wear tests must be performed at operating temperatures in order to be relevant. No significant effect of the type of water treatment on tube wear damage was observed. For predominantly impacting motion, the wear of SG tubes in contact with 410 stainless steel is similar regardless of whether Alloy 690 or Alloy 800 is used as tubing material or whether lattice bars or broached hole supports are used. Based on results presented in this paper, an average wear coefficient value is recommended that is used for the prediction of SG tube wear depth versus time

Impact fretting wear in CO2-based environments

International Nuclear Information System (INIS)

Levy, G.; Morri, J.

1985-01-01

An impact wear model, based on the load-sliding distance proportionality of wear and the mechanical response of the impacting bodies, was derived and tested against experiment. The experimental work was carried out on a twin vibrator rig capable of repetitive impact of a moving specimen against a stationary target material. The impact wear characteristics of three materials (mild steel, 9Cr-1Mo steel and austenitic 316 steel) against 310 stainless steel were examined over a range of temperatures (18-600 0 C). Additionally the effects of variations in the mechanical parameters (incident energy, ξ i , number N of impacts and angle of incidence φ) as a function of temperature were evaluated for mild steel only. The model was verified for impacting within a stable wear regime at 100 0 C for 9Cr-1Mo steel. The emergence of a severe-to-mild wear transition at elevated temperatures (200-400 0 C), however, introduced an energy and a 'numbers of cycles' effect that caused apparent deviations from theory. It was concluded that for stable single-mechanism wear regimes (metallic, oxidative etc.) oblique elastic impacts with a gross slip component were accurately described by the proposed impact wear model. (orig.)

The role of specimen temperature difference in the elevated temperature pitting/transfer of PE16 and 20/25/Nb SS during impact wear

International Nuclear Information System (INIS)

Morri, J.

1989-01-01

A previous study of the impact fretting wear characteristics of PE16 + impacting 20/25 Nb SS (carried out on the BNL twin vibrator rig) identified a pitting-transfer form of wear at 480 0 C. This behaviour was thought to be dependent upon the temperature difference ΔT(ΔT = T 20/25 -T PE 16 ) between the two specimens. In that series of tests, however, no localised temperature control over the specimens was possible and specimen temperature effects could only be assessed by interchanging their positions in the rig. The introduction of locally positioned auxilliary heaters permitted a degree of control over the specimen temperature difference. The effect of ΔT upon pitting and transfer of the PE16 and 20/25 was then assessed and is reported in this paper. The study confirmed that the pitting transfer process was dependent on the temperature difference between the two surfaces. The direction and size of the transfer/pitting effect was independent of the material. Under the particular set of conditions employed in the test, pitting occurred only when the magnitude of ΔT exceeded 20 0 C. At high ΔT the initial period of high friction was extended and was associated with the tendency for gross transfer and pitting. (author)

A study on die wear model of warm and hot forgings

Science.gov (United States)

Kang, J. H.; Park, I. W.; Jae, J. S.; Kang, S. S.

1998-05-01

Factors influencing service lives of tools in warm and hot forging processes are wear, mechanical fatigue, plastic deformation and thermal fatigue, etc. Wear is the predominant factor for tool failure among these. To predict tool life by wear, Archard's model where hardness is considered as constant or function of temperature is generally applied. Usually hardness of die is a function of not only temperature but operating time of die. To consider softening of die by repeated operation it is necessary to express hardness of die by a function of temperature and time. In this study wear coefficients were measured for various temperatures and heat treatment for H13 tool steel. Also by experiment of reheating of die, die softening curves were obtained. From experimental results, relationships between tempering parameters and hardness were established to investigate effects of hardness decrease by the effect of temperatures and time. Finally modified Archard's wear model in which hardness is considered to be a function of main tempering curve was proposed. And finite element analyses were conducted by adopting suggested wear model. By comparisons of simulations and real profiles of worn die, proposed wear model was verified.

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...

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

Truck tyre wear assessment and prediction

NARCIS (Netherlands)

Lupker, H.A.; Montanaro, F.; Donadio, D.; Gelosa, E.; Vis, M.A.

2002-01-01

Tyre wear is a complex phenomenon. It depends non-linearly on numerous parameters, like tyre compound and design, vehicle type and usage, road conditions and road surface characteristics, environmental conditions (e.g., temperature) and many others. Yet, tyre wear has many economic and ecological

Research on Oxidation Wear Behavior of a New Hot Forging Die Steel

Science.gov (United States)

Shi, Yuanji; Wu, Xiaochun

2018-01-01

Dry sliding tests for the hot forging die steel DM were performed in air under the test temperature at 400-700 °C and the time of 0.5-4 h by a UMT-3 high-temperature wear tester. The wear behavior and characteristics were studied systematically to explore the general characters in severe oxidation conditions. The results showed that a mild-to-severe oxidation wear transition occurred with an increase in the test temperature and duration. The reason was clarified as the unstable M6C carbides coarsening should be responsible for the severe delamination of tribo-oxide layer. More importantly, an intense oxidation wear with lower wear rates was found when the experimental temperature reaches 700 °C or after 4 h of test time at 600 °C, which was closely related to the degradation behavior during wear test. Furthermore, a new schematic diagram of oxidation wear of DM steel was proposed.

Testing of a Fiber Optic Wear, Erosion and Regression Sensor

Science.gov (United States)

Korman, Valentin; Polzin, Kurt A.

2011-01-01

The nature of the physical processes and harsh environments associated with erosion and wear in propulsion environments makes their measurement and real-time rate quantification difficult. A fiber optic sensor capable of determining the wear (regression, erosion, ablation) associated with these environments has been developed and tested in a number of different applications to validate the technique. The sensor consists of two fiber optics that have differing attenuation coefficients and transmit light to detectors. The ratio of the two measured intensities can be correlated to the lengths of the fiber optic lines, and if the fibers and the host parent material in which they are embedded wear at the same rate the remaining length of fiber provides a real-time measure of the wear process. Testing in several disparate situations has been performed, with the data exhibiting excellent qualitative agreement with the theoretical description of the process and when a separate calibrated regression measurement is available good quantitative agreement is obtained as well. The light collected by the fibers can also be used to optically obtain the spectra and measure the internal temperature of the wear layer.

Microstructure and wear behavior of austempered high carbon high silicon steel

Directory of Open Access Journals (Sweden)

Acharya Palaksha

2018-01-01

Full Text Available In the present investigation, the influence of austempering temperature and time on the microstructure and dry sliding wear behavior of high silicon steel was studied. The test specimens were initially austenitised at 900°C for 30 minutes, thereafter austempered at various temperatures 280°C, 360°C and 400°C, for varying duration from 30 to 120 minutes. These samples after austempering heat treatment were subsequently air cooled to room temperature, to generate typical ausferritic microstructures and then correlated with the wear property. The test outcomes demonstrate the slight increase in specific wear rate with increase in both austempering temperature and time. Specific wear rate was found to be minimum at an austempering temperature of 280°C, that exhibits lower bainite microstructure with high hardness, on the other hand specific wear rate was found to be slightly high at increased austempering temperatures at 360°C and 400°C, due to the upper bainite structure that offered lower hardness to the matrix. The sample austempered at 280°C for 30 minutes offered superior wear resistance when compared to other austempering conditions, mainly due to the presence of fine acicular bainitic ferrite along with stabilized retained austenite and also some martensite in the microstructure.

Rapid Analyses of Polyetheretherketone Wear Characteristics by Accelerated Wear Testing with Microfabricated Surfaces for Artificial Joint Systems.

Science.gov (United States)

Su, Chen-Ying; Kuo, Chien-Wei; Fang, Hsu-Wei

2017-01-01

Wear particle-induced biological responses are the major factors resulting in the loosening and then failure of total joint arthroplasties. It is feasible to improve the lubrication and reduce the wear of artificial joint system. Polyetheretherketone (PEEK) is considered as a potential bearing material due to its mechanical characteristics of resistance to fatigue strain. The PEEK wear particles have been indicated to be involved in biological responses in vitro, and further studies regarding the wear phenomena and wear particle generation are needed. In this study, we have established an accelerated wear testing system with microfabricated surfaces. Various contact pressures and lubricants have been utilized in the accelerated wear tests. Our results showed that increasing contact pressure resulted in an increase of wear particle sizes and wear rate, and the size of PEEK wear particles can be controlled by the feature size of microfabricated surfaces. These results provided the information rapidly about factors that affect the morphology and amount of PEEK wear particles and can be applied in the future for application of PEEK on the biological articulation system.

Effect of temperature on tribological properties of palm biodiesel

Energy Technology Data Exchange (ETDEWEB)

Haseeb, A.S.M.A.; Sia, S.Y.; Fazal, M.A.; Masjuki, H.H. [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2010-03-15

Biodiesel, as an alternative fuel is steadily gaining attention to replace petroleum diesel partially or completely. The tribological performance of biodiesel is crucial for its application in automobiles. In the present study, effect of temperature on the tribological performance of palm biodiesel was investigated by using four ball wear machine. Tests were conducted at temperatures 30, 45, 60 and 75 C, under a normal load of 40 kg for 1 h at speed 1200 rpm. For each temperature, the tribological properties of petroleum diesel (B0) and three biodiesel blends like B10, B20, B50 were investigated and compared. During the wear test, frictional torque was recorded on line. Wear scars in tested ball were investigated by optical microscopy. Results show that friction and wear increase with increasing temperature. (author)

Friction and wear behavior of steam-oxidized ferrous PM compacts

Energy Technology Data Exchange (ETDEWEB)

Raj, P. Philomen-D-Anaand; GopalaKrishna, A. [Dept. of Mechanical Engineering, Jawaharlal Nehru Technological University, Kakinada (India); Palaniradja, K [Dept. of Mechanical Engineering, Pondicherry Engineering College, Pondicherry (India)

2016-10-15

This study determines density effect by assessing sintering temperature and graphite content on the dry sliding wear characteristics of steam-treated iron materials using a pin-on-disk wear test. The specimens were prepared from atomized premixed iron base powders and contained 0.1 to 1.0 wt.% carbon compacted at different densities (5.9 g/cc to 6.8 g/cc). The specimens were sintered for 1 h at different sintering temperatures (1090°C to 1130°C), and then subjected to continuous steam treatment at 540°C for 95 min through in situ Powder metallurgy (PM) technique. Steam treatment was proposed to improve the wear performances of the components of PM. Wear tests were conducted using a pin-on-disk-type machine. Load ranged from 20 N to 60 N. Sliding distance and sliding velocity of 312 m and 0.26 m/s, respectively, were adopted for all tests. Scanning electron microscope was used to analyze wear surface. Increased density and graphite content reduced the wear rate of steam-treated materials. Hardness increased with increasing graphite content. Wear mechanism, wear rate map, and wear maps were drawn for the test result data. Wear transition map identified mild, severe, and ultra-severe wear regimes as functions of applied load.

Reciprocating wear in a steam environment

Energy Technology Data Exchange (ETDEWEB)

Brown, L.J.; Gee, M.G. [National Physical Laboratory, Teddington, Middlesex (United Kingdom)

2010-07-01

Tests to simulate the wear between sliding components in steam power plant have been performed using a low frequency wear apparatus at elevated temperatures under static load, at ambient pressure, in a steam environment. The apparatus was modified to accept a novel method of steam delivery. The materials tested were pre-exposed in a flowing steam furnace at temperature for either 500 or 3000 hours to provide some simulation of long term ageing. The duration of each wear test was 50 hours and tests were also performed on as-received material for comparison purposes. Data has been compared with results of tests performed on non-oxidised material for longer durations and also on tests without steam to examine the effect of different environments. Data collected from each test consists of mass change, stub height measurement and friction coefficient as well as visual inspection of the wear track. Within this paper, it is reported that both pre-ageing and the addition of steam during testing clearly influence the friction between material surfaces. (orig.)

Prediction of the wear and evolution of cutting tools in a carbide / titanium-aluminum-vanadium machining tribosystem by volumetric tool wear characterization and modeling

Science.gov (United States)

Kuttolamadom, Mathew Abraham

The objective of this research work is to create a comprehensive microstructural wear mechanism-based predictive model of tool wear in the tungsten carbide / Ti-6Al-4V machining tribosystem, and to develop a new topology characterization method for worn cutting tools in order to validate the model predictions. This is accomplished by blending first principle wear mechanism models using a weighting scheme derived from scanning electron microscopy (SEM) imaging and energy dispersive x-ray spectroscopy (EDS) analysis of tools worn under different operational conditions. In addition, the topology of worn tools is characterized through scanning by white light interferometry (WLI), and then application of an algorithm to stitch and solidify data sets to calculate the volume of the tool worn away. The methodology was to first combine and weight dominant microstructural wear mechanism models, to be able to effectively predict the tool volume worn away. Then, by developing a new metrology method for accurately quantifying the bulk-3D wear, the model-predicted wear was validated against worn tool volumes obtained from corresponding machining experiments. On analyzing worn crater faces using SEM/EDS, adhesion was found dominant at lower surface speeds, while dissolution wear dominated with increasing speeds -- this is in conformance with the lower relative surface speed requirement for micro welds to form and rupture, essentially defining the mechanical load limit of the tool material. It also conforms to the known dominance of high temperature-controlled wear mechanisms with increasing surface speed, which is known to exponentially increase temperatures especially when machining Ti-6Al-4V due to its low thermal conductivity. Thus, straight tungsten carbide wear when machining Ti-6Al-4V is mechanically-driven at low surface speeds and thermally-driven at high surface speeds. Further, at high surface speeds, craters were formed due to carbon diffusing to the tool surface and

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

Directory of Open Access Journals (Sweden)

Boyuan Huang

2017-02-01

Full Text Available 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.

Preparation, characterization and wear behavior of carbon coated magnesium alloy with electroless plating nickel interlayer

International Nuclear Information System (INIS)

Mao, Yan; Li, Zhuguo; Feng, Kai; Guo, Xingwu; Zhou, Zhifeng; Dong, Jie; Wu, Yixiong

2015-01-01

Highlights: • The carbon film with nickel interlayer (Ni + C coating) is deposited on GW83. • In Ni + C composite coating the carbon coating has good adhesion with the nickel interlayer. • The wear track of Ni + C coating is narrower compared to the bare one. • The wear resistance of GW83 is greatly improved by the Ni + C coating. - Abstract: Poor wear resistance of rare earth magnesium alloys has prevented them from wider application. In this study, composite coating (PVD carbon coating deposited on electroless plating nickel interlayer) is prepared to protect GW83 magnesium alloys against wear. The Ni + C composite coating has a dense microstructure, improved adhesion strength and hardness due to the effective support of Ni interlayer. The wear test result shows that the Ni + C composite coating can greatly prolong the wear life of the magnesium alloy. The wear track of the Ni + C coated magnesium alloy is obviously narrower and shows less abrasive particles as compared with the bare one. Abrasive wear is the wear mechanism of the coatings at the room temperature. In conclusion, the wear resistance of the GW83 magnesium alloy can be greatly improved by the Ni + C composite coating

Wear Characteristics of Metallic Biomaterials: A Review

Science.gov (United States)

Hussein, Mohamed A.; Mohammed, Abdul Samad; Al-Aqeeli, Naser

2015-01-01

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.

Variability of Battery Wear in Light Duty Plug-In Electric Vehicles Subject to Ambient Temperature, Battery Size, and Consumer Usage: Preprint

Energy Technology Data Exchange (ETDEWEB)

Wood, E.; Neubauer, J.; Brooker, A. D.; Gonder, J.; Smith, K. A.

2012-08-01

Battery wear in plug-in electric vehicles (PEVs) is a complex function of ambient temperature, battery size, and disparate usage. Simulations capturing varying ambient temperature profiles, battery sizes, and driving patterns are of great value to battery and vehicle manufacturers. A predictive battery wear model developed by the National Renewable Energy Laboratory captures the effects of multiple cycling and storage conditions in a representative lithium chemistry. The sensitivity of battery wear rates to ambient conditions, maximum allowable depth-of-discharge, and vehicle miles travelled is explored for two midsize vehicles: a battery electric vehicle (BEV) with a nominal range of 75 mi (121 km) and a plug-in hybrid electric vehicle (PHEV) with a nominal charge-depleting range of 40 mi (64 km). Driving distance distributions represent the variability of vehicle use, both vehicle-to-vehicle and day-to-day. Battery wear over an 8-year period was dominated by ambient conditions for the BEV with capacity fade ranging from 19% to 32% while the PHEV was most sensitive to maximum allowable depth-of-discharge with capacity fade ranging from 16% to 24%. The BEV and PHEV were comparable in terms of petroleum displacement potential after 8 years of service, due to the BEV?s limited utility for accomplishing long trips.

A comparative study on the fretting wear properties of advanced zirconium fuel cladding materials

International Nuclear Information System (INIS)

Lee, Young Ho; Kim, Hyung Kyu; Park, Jeong Yong; Kim, Jun Hwan

2005-06-01

Fretting wear tests were carried out in room and high temperature water in order to evaluate the wear properties of new zirconium nuclear fuel claddings (K2∼K6) and the commercial claddings (M5, zirlo and zircaloy-4). The objective is to compare the wear resistance of K2∼K6 claddings with that of the commercial ones at the same test condition. After the wear tests, the average wear volume and the maximum wear depth were evaluated and compared at each test condition. As a result, it is difficult to select the most wear-resistant cladding between the K2∼K6 claddings and the commercial ones. This is because the average wear volume and maximum depth of each cladding included between the scattering range of measured results. However, wear resistance of the tested claddings based on the average wear volume and maximum wear depth could be summarized as follows: K5 > zircaloy-4 > (K2,K3) > (K4,M5) > K6 > zirlo at room temperature, zircaloy-4 > K5 > (K3,K4,zirlo) > (K2,K6) > M5 at high temperature and pressure. Therefore, it is concluded that K5 cladding among the tested new zirconium alloys has relatively higher wear-resistance in room and high temperature condition. In order to examine the wear mechanism, it is necessary to systematically study with the consideration of the alloying element effect and test environment. In this report, the wear test procedure and the wear evaluation method are described in detail

Wearable Android Android wear and Google Fit app development

CERN Document Server

Mishra, Sanjay M

2015-01-01

Software Development/Mobile/Android/Wearable/Fitness Build ""Wearable"" Applications on the Android Wear and Google Fit Platforms This book covers wearable computing and wearable application development particularly for Android Wear (smartwatches) and Google Fit (fitness sensors). It provides relevant history, background and core concepts of wearable computing and ubiquitous computing, as a foundation for designing/developing applications for the Android Wear and Google Fit platforms. This book is intended for Android wearable enthusiasts, technologists and software developers. Gain ins

Development and characterization of laser clad high temperature self-lubricating wear resistant composite coatings on Ti–6Al–4V alloy

International Nuclear Information System (INIS)

Liu, Xiu-Bo; Meng, Xiang-Jun; Liu, Hai-Qing; Shi, Gao-Lian; Wu, Shao-Hua; Sun, Cheng-Feng; Wang, Ming-Di; Qi, Long-Hao

2014-01-01

Highlights: • A novel high temperature self-lubricating anti-wear composite coating was fabricated. • Reinforced carbides as well as self-lubricating sulfides were in situ synthesized. • Microhardness of the Ti–6Al–4V substrate was significantly improved. • Friction coefficient and wear rate of the composite coating were greatly reduced. - Abstract: To enhance the wear resistance and friction-reducing capability of titanium alloy, a process of laser cladding γ-NiCrAlTi/TiC + TiWC 2 /CrS + Ti 2 CS coatings on Ti–6Al–4V alloy substrate with preplaced NiCr/Cr 3 C 2 –WS 2 mixed powders was studied. A novel coating without cracks and few pores was obtained in a proper laser processing. The composition and microstructure of the fabricated coating were examined by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) techniques, and tribological properties were evaluated using a ball-on-disc tribometer under dry sliding wear test conditions at 20 °C (room-temperature), 300 °C, 600 °C, respectively. The results show that the coating has unique microstructure consisting of α-Ti, TiC, TiWC 2 , γ-NiCrAlTi, Ti 2 CS and CrS phases. Average microhardness of the composite coating is 1005 HV 0.2 , which is about 3-factor higher than that of Ti–6Al–4V substrate (360 HV 0.2 ). The friction coefficient and wear rate of the coating are greatly decreased due to the combined effects of the dominating anti-wear capabilities of reinforced TiC and TiWC 2 carbides and the CrS and Ti 2 CS sulfides which have excellent self-lubricating property

Wear Analysis of Top Piston Ring to Reduce Top Ring Reversal Bore Wear

Directory of Open Access Journals (Sweden)

P. Ilanthirayan

2017-12-01

Full Text Available The piston rings are the most important part in engine which controls the lubricating oil consumption and blowby of the gases. The lubricating film of oil is provided to seal of gases towards crankcase and also to give smooth friction free translatory motion between rings and liner. Of the three rings present top ring is more crucial as it does the main work of restricting gases downwards the crankcase. Boundary lubrication is present at the Top dead centre (TDC and Bottom dead centre (BDC of the liner surface. In addition to this, top ring is exposed to high temperature gases which makes the oil present near the top ring to get evaporated and decreasing its viscosity, making metal-metal contact most of the time. Due to this at TDC, excess wear happens on the liner which is termed as Top ring reversal bore wear. The wear rate depends upon many parameters such as lubrication condition, viscosity index, contact type, normal forces acting on ring, geometry of ring face, surface roughness, material property. The present work explores the wear depth for different geometries of barrel ring using Finite Element model with the help of Archard wear law and the same is validated through experimentation. The study reveals that Asymmetric barrel rings have less contact pressure which in turn reduces the wear at Top dead centre.

A Low-wear Planar-contact Silicon Raceway for Microball Bearing Applications

Science.gov (United States)

2009-04-01

of friction between stainless steel microballs and silicon grooves (18–20). Both linear and rotary micromotors for sensor platforms were developed...mechanism, like a micromotor , will enable devices to reach higher speeds. Previously, the radial surface wear track depth was >15 m for a device...can lead to significant whirl and axial misalignment, which is critical for micromotor and micropump applications. Small changes in the alignment

Laser surface melting of 10 wt% Mo alloyed hardfacing Stellite 12 plasma transferred arc deposits: Structural evolution and high temperature wear performance

Science.gov (United States)

Dilawary, Shaikh Asad Ali; Motallebzadeh, Amir; Afzal, Muhammad; Atar, Erdem; Cimenoglu, Huseyin

2018-05-01

Laser surface melting (LSM) process has been applied on the plasma transferred arc (PTA) deposited Stellite 12 and 10 wt% Mo alloyed Stellite 12 in this study. Following the LSM process, structural and mechanical property comparison of the LSM'ed surfaces has been made. Hardness of the LSM'ed surfaces was measured as 549 HV and 623 HV for the Stellite 12 and Stellite 12 + 10 wt% Mo deposits, respectively. Despite their different hardness and structural features, the LSM'ed surfaces exhibited similar tribological performance at room temperature (RT), where fatigue wear mechanism operates. However, the wear at 500 °C promotes tribo-oxide layer formation whose composition depended on the alloying with Mo. Thus, addition of 10 wt% Mo into Stellite 12 PTA deposit has remarkably enhanced the high temperature wear performance of the LSM'ed surface as a result of participation of complex oxide (CoMoO4) in tribo-oxide layer.

Radiation tagging measures wear at speed

International Nuclear Information System (INIS)

Barrett, Jon.

1994-01-01

A new non-invasive technique for performing accelerated wear and corrosion analysis is particularly relevant to power transmission systems. Wear tests that would normally take days or weeks to complete can now be performed in hours. A tiny patch of the wearing component is made mildly radioactive and the drop in activity as material is worn away is monitored. Known as Thin Layer Activation (TLA), the technology was originally developed and pioneered in-house by the Atomic Energy Authority. Since then, the dominant partner has been the automotive sector where TLA has been used extensively for engine wear and lubrication performance analysis. However, TLA could be used in any wear or corrosion environment. Applications include wear analysis of machine tool cutting surfaces, pump impellers and brake linings to the corrosion monitoring of process plant and pipelines. (author)

The Wear Characteristics of Heat Treated Manganese Phosphate Coating Applied to AlSi D2 Steel with Oil Lubricant

Directory of Open Access Journals (Sweden)

Venkatesan Alankaram

2012-12-01

Full Text Available Today, in the area of material design conversion coatings play an important role in the applications where temperature, corrosion, oxidation and wear come in to play. Wear of metals occurs when relative motion between counter-surfaces takes place, leading to physical or chemical destruction of the original top layers. In this study, the tribological behaviour of heat treated Manganese phosphate coatings on AISI D2 steel with oil lubricant was investigated. The Surface morphology of manganese phosphate coatings was examined by Scanning Electron Microscope (SEM and Energy Dispersive X-ray Spectroscopy (EDX .The wear tests were performed in a pin on disk apparatus as per ASTM G-99 Standard. The wear resistance of the coated steel was evaluated through pin on disc test using a sliding velocity of 3.0m/s under Constant loads of 40 N and 100 N with in controlled condition of temperature and humidity. The Coefficient of friction and wear rate were evaluated. Wear pattern of Manganese phosphate coated pins with oil lubricant, Heat treated Manganese phosphate coated pins with oil lubricant were captured using Scanning Electron Microscope (SEM. The results of the wear test established that the heat treated manganese phosphate coating with oil lubricant exhibited the lowest average coefficient of friction and the lowest wear loss up to 6583 m sliding distance under 40 N load and 3000 m sliding distance even under 100 N load respectively. The Wear volume and temperature rise in heat treated Manganese Phosphate coated pins with oil lubricant is lesser than the Manganese Phosphate coated pins with oil lubricant

Tooth wear and wear investigations in dentistry.

Science.gov (United States)

Lee, A; He, L H; Lyons, K; Swain, M V

2012-03-01

Tooth wear has been recognised as a major problem in dentistry. Epidemiological studies have reported an increasing prevalence of tooth wear and general dental practitioners see a greater number of patients seeking treatment with worn dentition. Although the dental literature contains numerous publications related to management and rehabilitation of tooth wear of varying aetiologies, our understanding of the aetiology and pathogenesis of tooth wear is still limited. The wear behaviour of dental biomaterials has also been extensively researched to improve our understanding of the underlying mechanisms and for the development of restorative materials with good wear resistance. The complex nature of tooth wear indicates challenges for conducting in vitro and in vivo wear investigations and a clear correlation between in vitro and in vivo data has not been established. The objective was to critically review the peer reviewed English-language literature pertaining to prevalence and aetiology of tooth wear and wear investigations in dentistry identified through a Medline search engine combined with hand-searching of the relevant literature, covering the period between 1960 and 2011. © 2011 Blackwell Publishing Ltd.

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.

Millisecond bearing wear

International Nuclear Information System (INIS)

Blatchley, C.; Sioshansi, P.

1987-01-01

Radionuclides have been widely used for many purposes in medicine, metals, transportation, manufacturing and research. Approximately 200 artificially produced nuclides are commercially available from reactors or accelerator sources. Another 400 or so have properties which may make them useful if satisfactory methods of production can be developed. One of the most economically important industrial applications of radionuclides has been in wear measurement and condition monitoring in reciprocating engines. The general techniques developed for this purpose have also been applied in a number of other areas besides engine or lubrication studies. The wear of floor wax applied to linoleum, for example, has been measured by mixing shortlived radionuclides in the wax. In those applications where the material is tagged and then followed, the radionuclides are termed ''tracers,'' similar to the medical tracer materials used to measure uptake or metabolism of biologically active chemicals in the body. The alternate function for the radionuclides is to act as ''markers'' which indicate the amount of material which is remaining at the location of the original activation. Both approaches require that the debris removed from the surface must be carried away from the original site. The first application of radioactive tracers as a diagnostic tool in engines was in 1949. In this technique, an entire wearing part such as a piston ring or gear was first exposed to neutrons in a nuclear reactor. This caused the entire volume of the part to become radioactive. The part was next installed and exposed to wear in the operating engine. Detectors placed near the oil line, an oil filter or a sediment trap then determined the amount of debris from the part by counting the gamma rays escaping from the debris

Wear Behavior of Uncoated and Coated Tools under Complex Loading Conditions

Directory of Open Access Journals (Sweden)

M. Wieland

2012-03-01

Full Text Available In automotive industry crash relevant structures of the body in white are manufactured using the direct hot stamping process. Due to the high temperature difference between the hot blank and the cold tool surfaces and the relative movement between the blank and the tool surfaces during the forming operation, high thermal and mechanical loads are applied on the tool leading to excessive wear in terms of adhesion on the tool surfaces. One possibility to reduce wear of hot stamping tools is the application of tool coating systems. In the scope of this work uncoated and coated tools are characterized under complex loading conditions with respect to adhesive layer build-up.

A Possible Link Between Macroscopic Wear and Temperature Dependent Friction Behaviors of MoS2 Coatings

Science.gov (United States)

2008-09-01

measured during operation without breaking the gas environment. For this study, coatings were deposited on 304 stainless steel spheres and rectangular...activated behavior in macroscopic tribology is reserved for systems with stable interfaces and ultra-low wear, and athermal behavior is characteristic to...efforts to measure and under- stand tribological behavior at cryogenic temperatures; to date, results of these efforts show either no trend or con- flicting

Standard guide for measuring the wear volumes of piston ring segments run against flat coupons in reciprocating wear tests

CERN Document Server

American Society for Testing and Materials. Philadelphia

2011-01-01

1.1 This guide covers and describes a profiling method for use accurately measuring the wear loss of compound-curved (crowned) piston ring specimens that run against flat counterfaces. It does not assume that the wear scars are ideally flat, as do some alternative measurement methods. Laboratory-scale wear tests have been used to evaluate the wear of materials, coatings, and surface treatments that are candidates for piston rings and cylinder liners in diesel engines or spark ignition engines. Various loads, temperatures, speeds, lubricants, and durations are used for such tests, but some of them use a curved piston ring segment as one sliding partner and a flat or curved specimen (simulating the cylinder liner) as its counterface. The goal of this guide is to provide more accurate wear measurements than alternative approaches involving weight loss or simply measuring the length and width of the wear marks. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its ...

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.

A wear-resistant zirconia ceramic for low friction application

International Nuclear Information System (INIS)

Winnubst, A.J.A.; Ran, S.; Wiratha, K.W.; Blank, D.H.A.; Pasaribu, H.R.; Sloetjes, J.W.; Schipper, D.J.

2004-01-01

A high wear-resistant ceramic/ceramic couple is described associated with low friction. By adding a small amount CuO to yttria-doped tetragonal zirconia (Y-TZP) the (dry) coefficient of friction against alumina is only 0.2 during a sliding distance of 3-5 km after which the coefficient drastically increases and a transition from mild to sever wear occurs. Pure Y-TZP exhibits a coefficient of friction of 0.7 under the same experimental conditions but wear remains mild during the test (upto 10 km of sliding distance). These small amounts of CuO also strongly influence the densification behaviour. Sintering of this system occurs in several steps where among other things dissolution of CuO in the Y-TZP matrix as well as liquid phase sintering takes place. Non-uniform shrinkage of the CuO-doped system resulting in relative large microcracks in the ceramic can explain its sudden drastic increase in coefficient of friction and wear rate after 3-5 km of operation. (orig.)

Experimental Investigation on Tool Wear Behavior and Cutting Temperature during Dry Machining of Carbon Steel SAE 1030 Using KC810 and KC910 Coated Inserts

Directory of Open Access Journals (Sweden)

Y. Tamerabet

2018-03-01

Full Text Available The removal of cutting fluids and lubrication in dry machining operations requires a good knowledge and full control of all the mechanisms that lead to tool damage. In order to optimize dry machining operations, it is necessary to clearly identify the wear patterns, determine the contact conditions and define the relationship between the contact parameters and the operating conditions. The idea is to choose optimal cutting conditions which lead to the best contact conditions limiting the triggering or aggravation of wear phenomena. The purpose of this paper is to determine the impact multilayer coatings and cutting parameters on tool wear and temperature at the tool-chip interface for two types of coated carbides (KC810 and KC910 Commercialized inserts during dry turning operation of carbon steel SAE 1030, in order to determine the ideal parameters and guarantee the best performances of the cutting tools. Cutting temperature, Crater and Flank wear have been systematically recorded in order to determine their influence on tool life time. To ensure the optimum choice of machining conditions; the TAGUCHI method associated to multi-factorial method were applied to plan the experiments. It has been noted that cutting speed was the most influential factor on temperature and wear evolution. We noted also that the KC810 insert was more suitable for machining of SAE 1030 Carbon Steel; where The best life time was registered (T=228 min. The KC810 inserts offer 30 min of additional machining time for the same work conditions.

Demonstration for the Applicability of the EPRI ETSS on the SG Tube Wear Defects Formed at the Tube Support Structure

International Nuclear Information System (INIS)

Shin, Ki Seok; Cheon, Keun Young; Nam, Min Woo; Min, Kyong Mahn

2013-01-01

In this paper, the authorized EPRI ETSS 27906.2 applied to the detection of tapered wear volumetric indications and depth sizing within the free span area, loose part not present was reviewed and applied to the site SG tubes for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation. The experiment to demonstrate the applicability of EPRI ETSS was performed by the employment of the newly prepared STD tube and resulted in ensuring the effectiveness and equivalency of the EPRI ETSS as well. The authorized EPRI ETSS 27906.2 for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation was reviewed and applied to the site SG tubes. The testing results were reviewed with the influences of SG tube material and the support structure. The impact of the tube materials was insignificant and that of the tube support structure showed somewhat conservative results. The testing resulted in successful demonstration of applicability of the EPRI ETSS on the SG tube wear defects at the tube support. One of the major flaw mechanisms detected in the currently operating domestic OPR-1000 pressurized water reactors(PWR's) steam generator(SG) tubes is wear defect. In general, wear defect has been constantly detected in the upper tube bundle imposed to the flow induced vibration interaction between tube and its support structure, and the quantity of the affected tubes has also shown the tendency to increase as plant operation life is added. In order to take appropriate measures and maintain the structural integrity for the SG tubes, wear defect is currently categorized as active damage mechanism and the tubes containing 40% or greater wear depth of the nominal tube wall thickness shall be plugged per SGMP(SG Management Program) Recently, a fairly large amplitude of wear defects on the Batwing(BW), one of the upper tube support structures in the SG tubes

Demonstration for the Applicability of the EPRI ETSS on the SG Tube Wear Defects Formed at the Tube Support Structure

Energy Technology Data Exchange (ETDEWEB)

Shin, Ki Seok; Cheon, Keun Young; Nam, Min Woo [Korea Hydro and Nuclear Power Co. Ltd, Daejeon (Korea, Republic of); Min, Kyong Mahn [Universal Monitoring and Inspection Inc., Daejeon (Korea, Republic of)

2013-10-15

In this paper, the authorized EPRI ETSS 27906.2 applied to the detection of tapered wear volumetric indications and depth sizing within the free span area, loose part not present was reviewed and applied to the site SG tubes for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation. The experiment to demonstrate the applicability of EPRI ETSS was performed by the employment of the newly prepared STD tube and resulted in ensuring the effectiveness and equivalency of the EPRI ETSS as well. The authorized EPRI ETSS 27906.2 for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation was reviewed and applied to the site SG tubes. The testing results were reviewed with the influences of SG tube material and the support structure. The impact of the tube materials was insignificant and that of the tube support structure showed somewhat conservative results. The testing resulted in successful demonstration of applicability of the EPRI ETSS on the SG tube wear defects at the tube support. One of the major flaw mechanisms detected in the currently operating domestic OPR-1000 pressurized water reactors(PWR's) steam generator(SG) tubes is wear defect. In general, wear defect has been constantly detected in the upper tube bundle imposed to the flow induced vibration interaction between tube and its support structure, and the quantity of the affected tubes has also shown the tendency to increase as plant operation life is added. In order to take appropriate measures and maintain the structural integrity for the SG tubes, wear defect is currently categorized as active damage mechanism and the tubes containing 40% or greater wear depth of the nominal tube wall thickness shall be plugged per SGMP(SG Management Program) Recently, a fairly large amplitude of wear defects on the Batwing(BW), one of the upper tube support structures in the SG

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.

Wear behavior of steam generator tubes in nuclear power plant operating condition

International Nuclear Information System (INIS)

Kim, In-Sup; Hong, Jin-Ki; Kim, Hyung-Nam; Jang, Ki-Sang

2003-01-01

Reciprocating sliding wear tests were performed on steam generator tubes materials at steam generator operating temperature. The material surfaces react with oxygen to form oxides. The oxide properties such as formation rate and mechanical properties are varied with the test temperature and alloy composition. So, it is important to investigate the wear properties of each steam generator tube materials in steam generator operating condition. The tests results indicated that the wear coefficient in work rate model of alloy 690 was faster than that of alloy 800. From the scanning electron microscopy observation, the wear scars were similar each other and worn surfaces were covered with oxide layers. It seemed that the oxide layers were formed by wear debris sintering or cold welding and these layer properties affected the wear rate of steam generator tube materials. (author)

A WEAR MODEL FOR DIESEL ENGINE EXHAUST VALVES

Energy Technology Data Exchange (ETDEWEB)

Blau, Peter Julian [ORNL

2009-11-01

The work summarized here comprises the concluding effort of a multi-year project, funded by the U.S. Department of Energy, Office of Vehicle Technologies. It supports the development of a better understanding of advanced diesel engine designs in which enhanced power density, energy efficiency, and emissions control place increasing demands upon the durability of engine materials. Many kinds of metallic alloys are used in engines depending on the operating stresses, temperatures, and chemical environments. Exhaust valves, for example, are subjected to high temperatures and repetitive surface contacts that place demands on durability and frictional characteristics of the materials. Valves must continue to seal the combustion chamber properly for thousands of hours of cyclic engine operation and under varying operating conditions. It was the focus of this effort to understand the wear processes in the valve-seat area and to develop a model for the surface deformation and wear of that important interface. An annotated bibliography is provided to illustrate efforts to understand valve wear and to investigate the factors of engine operation that affect its severity and physical manifestation. The project for which this modeling effort was the final task, involved construction of a high-temperature repetitive impact test system as well as basic tribology studies of the combined processes of mechanical wear plus oxidation at elevated temperatures. Several publications resulted from this work, and are cited in this report. The materials selected for the experimental work were high-performance alloys based on nickel and cobalt. In some cases, engine-tested exhaust valves were made available for wear analysis and to ensure that the modes of surface damage produced in experiments were simulative of service. New, production-grade exhaust valves were also used to prepare test specimens for experimental work along with the other alloy samples. Wear analysis of valves and seats

Dry sliding wear of Ni alloyed austempered ductile iron

Directory of Open Access Journals (Sweden)

E. Akbarzadeh Chiniforush

2016-09-01

Full Text Available Measurements of dry sliding wear are presented for ductile irons with composition Fe-3.56C-2.67Si-0.25Mo-0.5Cu and Ni contents of 0.8 and 1.5 in wt.% with applied loads of 50, 100 and 150 N for austempering temperatures of 270, 320, and 370 °C after austenitizing at 870 °C for 120 min. The mechanical property measurements show that the grades of the ASTM 897M: 1990 Standard can be satisfied for the selected austempering conditions. The results show that wear resistance is independent of austempering temperature with an applied load of 50 N, but there is a strong dependence at higher austempering temperatures with applied loads of 100 and 150 N. Observations indicate that wear is due to subsurface fatigue with cracks nucleated at deformed graphite nodules.

Friction and wear in sodium

International Nuclear Information System (INIS)

Hoffman, N.J.; Droher, J.J.

1973-01-01

In the design of a safe and reliable sodium-cooled reactor one of the more important problem areas is that of friction and wear of components immersed in liquid sodium or exposed to sodium vapor. Sodium coolant at elevated temperatures may severely affect most oxide-bearing surface layers which provide corrosion resistance and, to some extent, lubrication and surface hardness. Consequently, accelerated deterioration may be experienced on engaged-motion contact surfaces, which could result in unexpected reactor shutdown from component malfunction or failure due to galling and seizure. An overall view of the friction and wear phenomena encountered during oscillatory rubbing of surfaces in high-temperature, liquid-sodium environments is presented. Specific data generated at the Liquid Metal Engineering Center (LMEC) on this subject is also presented. (U.S.)

Effect of Phenomena Accompanying Wear in Dry Corundum Abrasive on the Properties and Microstructure of Austempered Ductile Iron with Different Chemical Composition

Directory of Open Access Journals (Sweden)

Myszka D.

2015-04-01

Full Text Available The research described in this article is a fragment in the series of published works trying to determine the applicability of new materials for parts of the mining machinery. Tests were performed on two groups of austempered ductile iron - one of which contained 1.5% Ni and 0.5% Mo, while the other contained 1.9% Ni and 0.9% Cu. Each group has been heat treated according to the three different heat treatment variants and then the material was subjected to detailed testing of mechanical properties and abrasion wear resistance, measuring also hardness and magnetic properties, and conducting microstructural examinations. The results indicated that each of the tested materials was senstive to the surface hardening effect, which resulted in high wear resistance. It has been found that high temperature of austempering, i.e. 370°C, favours high wear resistance of ductile iron containing nickel and molybdenum. Low temperature of austempering, i.e. 270°C, develops high wear resistance in ductile iron containing nickel and copper. Both these materials offer completely different mechanical properties and as such can be used for different and specific applications.

Investigation of laser cladding high temperature anti-wear composite coatings on Ti6Al4V alloy with the addition of self-lubricant CaF2

International Nuclear Information System (INIS)

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

2014-01-01

Highlights: • A novel high temperature self-lubricating wear-resistant coating was fabricated. • TiC carbides and self-lubricant CaF 2 were “in situ” synthesized in the coating. • The coating with the addition of CaF 2 possessed superior properties than without. - Abstract: To improve the high-temperature tribological properties of Ti–6Al–4V alloy, γ-NiCrAlTi/TiC and γ-NiCrAlTi/TiC/CaF 2 coatings were fabricated on Ti–6Al–4V alloy by laser cladding. The phase compositions and microstructure of the coatings were investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). The tribological behaviors were evaluated using a ball-on-disk tribometer from ambient temperature to 600 °C under dry sliding wear conditions and the corresponding wear mechanisms were discussed. The results indicated that the γ-NiCrAlTi/TiC/CaF 2 coating consisted of α-Ti, the “in situ” synthesized TiC block particles and dendrite, γ-NiCrAlTi solid solution and spherical CaF 2 particles. The wear rates of γ-NiCrAlTi/TiC/CaF 2 coating were decreased greatly owing to the combined effects of the reinforced carbides and continuous lubricating films. Furthermore, the friction coefficients of γ-NiCrAlTi/TiC/CaF 2 coating presented minimum value of 0.21 at 600 °C, which was reduced by 43% and 50% compared to the substrate and γ-NiCrAlTi/TiC coating respectively. It was considered that the γ-NiCrAlTi/TiC/CaF 2 coating exhibited excellent friction-reducing and anti-wear properties at high temperature

Adhesion and wear properties of boro-tempered ductile iron

International Nuclear Information System (INIS)

Kayali, Yusuf; Yalcin, Yilmaz; Taktak, Suekrue

2011-01-01

Highlights: → In this study, the wear and adhesion properties of BDI were investigated. → Boro-tempering process under several heat treatment conditions was examined. → Optical microscope, SEM and XRD analysis were carried out to investigate the microstructure. → It was observed that boro-tempering process improves micro-hardness and wear properties of ductile irons. -- Abstract: In this study, adhesion and wear properties of boro-tempered ductile iron (BDI) were investigated. Boro-tempering was carried out on two stage processes i.e. boronizing and tempering. At the first stage, ductile iron samples were boronized by using pack process at 900 o C for 1, 3, and 5 h and then, secondly tempered at 250, 300, 350, and 400 o C for 1 h. X-ray diffraction (XRD) analysis of boro-tempered samples showed that FeB and Fe 2 B phases were found on the surface of the samples. The Daimler-Benz Rockwell-C adhesion test was used to assess the adhesion of boride layer. Test result showed that adhesion decreased with increasing boriding time and increased with increasing tempering temperature. Dry sliding wear tests of these samples were performed against Al 2 O 3 ball at a constant sliding speed and loads of 5 and 10 N. Wear tests indicated that boro-tempering heat treatment increased wear resistance of ductile iron. In addition, it was found that while wear rate of boro-tempered samples decreased with increasing boriding time, there is no significant affect of tempering temperature on wear rate.

Development of wear resistant NFSS-HA novel biocomposites and study of their tribological properties for orthopaedic applications.

Science.gov (United States)

Younesi, M; Bahrololoom, M E; Fooladfar, H

2010-02-01

Implants made of nickel free austenitic stainless steel can reduce the toxic effect of released nickel ion and compounds from the conventional stainless steels. On the other hand, hydroxyapatite is a ceramic which has been used in orthopaedic applications due to its good osteoconductivity, biocompatibility and bioactivity. However, there is no evidence in the literature up to now on producing composites based on nickel free stainless steel and hydroxyapatite and study of their tribology. The aim of this work was to produce novel biocomposites made up of nickel free stainless steel with hydroxyapatite (prepared by heat treating bone ash) and studying their tribology under various loads in air and in Ringer's physiological solution. Different amounts of hydroxyapatite powder (10, 20, 30 and 40% Vol.) were added to this nickel free stainless steel powder to get the biocomposites. Variation of their density, hardness, wear resistance and friction with the ceramic (hydroxyapatite) content and wear load were investigated in air and in Ringer's solution. The density of the composites was decreased by increasing the volume percentage of the hydroxyapatite, while wear resistance of the composites was increased. The wear mechanism of these composites was changed by increasing the wear load and consequently the volume loss was enhanced dramatically. Furthermore, by increasing the sliding distance, the rate of volume loss was decreased slightly. The friction coefficient of the composites was also decreased by increasing the weight percentage of hydroxyapatite. Effect of the physiological Ringer's solution on wear resistance and friction coefficient of the composites was nearly negligible. The wear mechanisms of the samples were identified by studying the SEM images of the worn surfaces of the tested samples in different wear loads and HA contents. Copyright 2009 Elsevier Ltd. All rights reserved.

Investigation of Wear Coefficient of Manganese Phosphate Coated Tool Steel

Directory of Open Access Journals (Sweden)

S. Ilaiyavel

2013-03-01

Full Text Available In recent years the properties of the coating in terms of wear resistance is of paramount importance in order to prevent the formation of severe damages. In this study, Wear coefficient of uncoated, Manganese Phosphate coated, Manganese Phosphate coated with oil lubricant, Heat treated Manganese Phosphate coated with oil lubricant on AISI D2 steels was investigated using Archard’s equation. The wear tests were performed in a pin on disk apparatus as per ASTM G-99 Standard. The volumetric wear loss and wear coefficient were evaluated through pin on disc test using a sliding velocity of 3.0 m/s under normal load of 40 N and controlled condition of temperature and humidity. Based on the results of the wear test, the Heat treated Manganese Phosphate with oil lubricant exhibited the lowest average wear coefficient and the lowest wear loss under 40 N load.

Application of Influence Function Method to the Fretting Wear Problems

Energy Technology Data Exchange (ETDEWEB)

Lee, Choon Yeol; Tian, Li Si; Bae, Joon Woo; Chai, Young Suck [Yeungnam University, Gyongsan (Korea, Republic of)

2006-07-01

Numerical analysis by influence function method (IFM) is demonstrated in this study in order to investigate the fretting wear problems on the secondary side of the steam generator, caused by flow induced vibration. Two-dimensional numerical contact model in terms of Cauchy integral equation is developed. The distributions of normal pressures, shear stresses and displacement fields are derived between two contact bodies which have similar elastic properties. The work rate model is adopted to find the wear amounts between two materials. The results are compared with the solutions by finite element analyses, which show the utilization of the present method to the fretting wear problems.

Application of Influence Function Method to the Fretting Wear Problems

International Nuclear Information System (INIS)

Lee, Choon Yeol; Tian, Li Si; Bae, Joon Woo; Chai, Young Suck

2006-01-01

Numerical analysis by influence function method (IFM) is demonstrated in this study in order to investigate the fretting wear problems on the secondary side of the steam generator, caused by flow induced vibration. Two-dimensional numerical contact model in terms of Cauchy integral equation is developed. The distributions of normal pressures, shear stresses and displacement fields are derived between two contact bodies which have similar elastic properties. The work rate model is adopted to find the wear amounts between two materials. The results are compared with the solutions by finite element analyses, which show the utilization of the present method to the fretting wear problems

Friction and wear behavior of laser cladding Ni/hBN self-lubricating composite coating

International Nuclear Information System (INIS)

Zhang Shitang; Zhou Jiansong; Guo Baogang; Zhou Huidi; Pu Yuping; Chen Jianmin

2008-01-01

Ni/hBN coating was successfully prepared on 1Cr18Ni9Ti stainless steel substrate by means of laser cladding. The microhardness profile of the composite coating along the depth direction was measured, while its cross-sectional microstructures and phase compositions were analyzed by means of scanning electron microscopy and X-ray diffraction. Moreover, the friction and wear behavior of the composite coatings sliding against Si 3 N 4 from ambient to 800 deg. C was evaluated using a ball-on-disc friction and wear tester, and the worn surface morphologies of the composite coatings and counterpart ceramic balls were observed using a scanning electron microscope. At the same time, the worn surfaces of the ceramic balls were also analyzed using a 3D non-contact surface mapping profiler as well. It was found that the laser cladding Ni/hBN coating on the stainless steel substrate had high microhardness and good friction-reducing and antiwear abilities at elevated temperatures up to 800 deg. C. The composite coating registered slightly increased friction coefficient and wear rate as the temperature rose from ambient to 100 deg. C; then the friction coefficient and wear rate decreased with increasing temperature up to 800 deg. C (with the slight increase in the wear rate at 700 deg. C and 800 deg. C to be an exception). The laser cladding Ni/hBN coating was dominated by mixed adhesion and abrasive wear as it slid against the ceramic ball below 300 deg. C. With further increase in the test temperature up to 400 deg. C and above, it was characterized by mild adhesion wear and plastic deformation. Since the laser cladding Ni/hBN coating registered an increased wear rate at temperatures of 600 deg. C and above, it was not suggested to be used for wear prevention and protection of the stainless steel at elevated temperature above 800 deg. C

Friction and wear behavior of laser cladding Ni/hBN self-lubricating composite coating

Energy Technology Data Exchange (ETDEWEB)

Zhang Shitang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhou Jiansong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Guo Baogang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhou Huidi [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Pu Yuping [Central Iron and Steel Research Institute, Beijing 100081 (China); Chen Jianmin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)], E-mail: chenjm@lzb.ac.cn

2008-09-15

Ni/hBN coating was successfully prepared on 1Cr18Ni9Ti stainless steel substrate by means of laser cladding. The microhardness profile of the composite coating along the depth direction was measured, while its cross-sectional microstructures and phase compositions were analyzed by means of scanning electron microscopy and X-ray diffraction. Moreover, the friction and wear behavior of the composite coatings sliding against Si{sub 3}N{sub 4} from ambient to 800 deg. C was evaluated using a ball-on-disc friction and wear tester, and the worn surface morphologies of the composite coatings and counterpart ceramic balls were observed using a scanning electron microscope. At the same time, the worn surfaces of the ceramic balls were also analyzed using a 3D non-contact surface mapping profiler as well. It was found that the laser cladding Ni/hBN coating on the stainless steel substrate had high microhardness and good friction-reducing and antiwear abilities at elevated temperatures up to 800 deg. C. The composite coating registered slightly increased friction coefficient and wear rate as the temperature rose from ambient to 100 deg. C; then the friction coefficient and wear rate decreased with increasing temperature up to 800 deg. C (with the slight increase in the wear rate at 700 deg. C and 800 deg. C to be an exception). The laser cladding Ni/hBN coating was dominated by mixed adhesion and abrasive wear as it slid against the ceramic ball below 300 deg. C. With further increase in the test temperature up to 400 deg. C and above, it was characterized by mild adhesion wear and plastic deformation. Since the laser cladding Ni/hBN coating registered an increased wear rate at temperatures of 600 deg. C and above, it was not suggested to be used for wear prevention and protection of the stainless steel at elevated temperature above 800 deg. C.

Friction and wear studies of graphite and a carbon-carbon composite in air and in helium

International Nuclear Information System (INIS)

Li, C.C.; Sheehan, J.E.

1980-10-01

Sliding friction and wear tests were conducted on a commercial isotropic graphite and a carbon-carbon composite in air, purified helium, and a helium environment containing controlled amounts of impurities simulating the primary coolant chemistry of a high-temperature gas-cooled reactor (HTGR). The friction and wear characteristics of the materials investigated were stable and were found to be very sensitive to the testing temperature. In general, friction and wear decreased with increasing temperature in the range from ambient to 950 0 C. This temperature dependence is concluded to be due to chemisorption of impurities to form lubricating films and oxidation at higher temperatures, which reduce friction and wear. Graphite and carbon-carbon composites are concluded to be favorable candidate materials for high-temperature sliding service in helium-cooled reactors

Investigation of laser cladding high temperature anti-wear composite coatings on Ti6Al4V alloy with the addition of self-lubricant CaF{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Xiang, Zhan-Feng [School of Mechanical and Electric Engineering, Soochow University, 178 East Ganjiang Road, Suzhou 215006 (China); Liu, Xiu-Bo, E-mail: liuxiubo@suda.edu.cn [School of Mechanical and Electric Engineering, Soochow University, 178 East Ganjiang Road, Suzhou 215006 (China); Ren, Jia; Luo, Jian; Shi, Shi-Hong; Chen, Yao [School of Mechanical and Electric Engineering, Soochow University, 178 East Ganjiang Road, Suzhou 215006 (China); Shi, Gao-Lian; Wu, Shao-Hua [Suzhou Institute of Industrial Technology, Suzhou 215104 (China)

2014-09-15

Highlights: • A novel high temperature self-lubricating wear-resistant coating was fabricated. • TiC carbides and self-lubricant CaF{sub 2} were “in situ” synthesized in the coating. • The coating with the addition of CaF{sub 2} possessed superior properties than without. - Abstract: To improve the high-temperature tribological properties of Ti–6Al–4V alloy, γ-NiCrAlTi/TiC and γ-NiCrAlTi/TiC/CaF{sub 2} coatings were fabricated on Ti–6Al–4V alloy by laser cladding. The phase compositions and microstructure of the coatings were investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). The tribological behaviors were evaluated using a ball-on-disk tribometer from ambient temperature to 600 °C under dry sliding wear conditions and the corresponding wear mechanisms were discussed. The results indicated that the γ-NiCrAlTi/TiC/CaF{sub 2} coating consisted of α-Ti, the “in situ” synthesized TiC block particles and dendrite, γ-NiCrAlTi solid solution and spherical CaF{sub 2} particles. The wear rates of γ-NiCrAlTi/TiC/CaF{sub 2} coating were decreased greatly owing to the combined effects of the reinforced carbides and continuous lubricating films. Furthermore, the friction coefficients of γ-NiCrAlTi/TiC/CaF{sub 2} coating presented minimum value of 0.21 at 600 °C, which was reduced by 43% and 50% compared to the substrate and γ-NiCrAlTi/TiC coating respectively. It was considered that the γ-NiCrAlTi/TiC/CaF{sub 2} coating exhibited excellent friction-reducing and anti-wear properties at high temperature.

Friction and wear methodologies for design and control

CERN Document Server

Straffelini, Giovanni

2015-01-01

This book introduces the basic concepts of contact mechanics, friction, lubrication, and wear mechanisms, providing simplified analytical relationships that are useful for quantitative assessments. Subsequently, an overview on the main wear processes is provided, and guidelines on the most suitable design solutions for each specific application are outlined. The final part of the text is devoted to a description of the main materials and surface treatments specifically developed for tribological applications and to the presentation of tribological systems of particular engineering relevance. The text is up to date with the latest developments in the field of tribology and provides a theoretical framework to explain friction and wear problems, together with practical tools for their resolution. The text is intended for students on Engineering courses (both bachelor and master degrees) who must develop a sound understanding of friction, wear, lubrication, and surface engineering, and for technicians or professi...

Friction and wear properties of Cu and Fe-based P/M bearing materials

International Nuclear Information System (INIS)

Tufekci, Kenan; Kurbanoglu, Cahit; Durak, Ertugrul; Tunay, R. Fatih

2006-01-01

The performances of porous bearings under different operating conditions were experimentally investigated in this study. Material groups studied are 90%Cu + 10%Sn bronze and 1%C + % balance Fe iron-based self-lubricating P/M bearings at constant (85%) density. In the experiments, the variation of the coefficient of friction and wear ratio of those two different group materials for different sliding speeds, loads, and temperatures were investigated. As a result, the variation of the friction coefficient - temperature for both constant load, and constant sliding speed, friction coefficient - average bearing pressure, PV - wear loss and temperature-wear loss curves were plotted and compared with each other for two materials, separately. The test results showed that Cu-based bearings have better friction and wear properties than Fe-based bearings

Effect of the low temperature ion nitriding on the wear and corrosion resistance of 316L austenitic stainless steel biomaterials

International Nuclear Information System (INIS)

Sudjatmoko; Bambang Siswanto; Wirjoadi; Lely Susita RM

2012-01-01

In the present study has been completed done the ion nitriding process and characterization of the 316L SS samples. The ion nitriding process has been conducted on the samples for nitriding temperature variation of 350, 400, 450, 500, and 550 °C, the optimum nitrogen gas pressure of 1.8 mbar and optimum nitriding time of 3 hours. The micro-structure, elemental composition and the phase structure of the nitride layer formed on the surface of samples were observed using the techniques of SEM-EDAX and XRD, respectively. It is known that a thin layer of iron nitrides has been formed on the surface of the samples. Iron nitride layer has a phase structure including ε-Fe_2_-_3N, γ'-Fe_4N, CrN, Cr_2N and expanded austenite γN. The characterization results of the wear resistance of the 316L SS samples showed an increasing of about 2.6 times the wear resistance of standard samples after nitriding temperature of 350 °C. From the corrosion test by using the Hanks solution was obtained 29.87 mpy corrosion rate or the increasing of corrosion resistance of about 137%. Thus it can be seen that by using ion nitriding technique the iron nitride layer has been formed on the surface of the 316L SS samples, and they have an excellent properties of wear resistance and corrosion resistance, which were caused especially due to the formation of an expanded austenite γN. Properties of the high hardness and has the good corrosion resistance, especially due to the formation of iron nitride and expanded austenite phases γN at low temperature nitriding process. (author)

Optimization of pulsed DC PACVD parameters: Toward reducing wear rate of the DLC films

International Nuclear Information System (INIS)

Ebrahimi, Mansoureh; Mahboubi, Farzad; Naimi-Jamal, M. Reza

2016-01-01

Highlights: • Effect of pulsed DC PACVD deposition temperature, duty cycle, hydrogen flow and argon/CH4 flow ratio on the wear rate and durability of DLC films was studied. • Results show that wear rate of the DLC films, reduced from 14×E-4 mm3/Nm to 1×E-6 mm3/Nm with increasing the duty cycle from 50% to 80%. • In low duty cycle (around 50%), wear rate increases with increasing in Argon/CH4 flow ratio. • Oxidation, fatigue, abrasion and graphitization are main wear mechanisms in the DLC film. - Abstract: The effect of pulsed direct current (DC) plasma-assisted chemical vapor deposition (PACVD) parameters such as temperature, duty cycle, hydrogen flow, and argon/CH_4 flow ratio on the wear behavior and wear durability of the diamond-like carbon (DLC) films was studied by using response surface methodology (RSM). DLC films were deposited on nitrocarburized AISI 4140 steel. Wear rate and wear durability of the DLC films were examined with the pin-on-disk method. Field emission scanning electron microscopy, Raman spectroscopy, and nanoindentation techniques were used for studying wear mechanisms, chemical structure, and hardness of the DLC films. RSM results show that duty cycle is one of the important parameters that affect the wear rate of the DLC samples. The wear rate of the samples deposited with a duty cycle of >75% decreases with an increase in the argon/CH4 ratio. In contrast, for a duty cycle of <65%, the wear rate increases with an increase in the argon/CH_4 ratio. The wear durability of the DLC samples increases with an increase in the duty cycle, hydrogen flow, and argon/CH_4 flow ratio at the deposition temperature between 85 °C and 110 °C. Oxidation, fatigue, abrasive wear, and graphitization are the wear mechanisms observed on the wear scar of the DLC samples deposited with the optimum deposition conditions.

Optimization of pulsed DC PACVD parameters: Toward reducing wear rate of the DLC films

Energy Technology Data Exchange (ETDEWEB)

Ebrahimi, Mansoureh [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, P.O. Box 1875-4413, Tehran (Iran, Islamic Republic of); Mahboubi, Farzad, E-mail: mahboubi@aut.ac.ir [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, P.O. Box 1875-4413, Tehran (Iran, Islamic Republic of); Naimi-Jamal, M. Reza [Research Laboratory of Green Organic Synthesis and Polymers, Department of Chemistry, Iran University of Science and Technology, P.O. Box 16846, Tehran (Iran, Islamic Republic of)

2016-12-15

Highlights: • Effect of pulsed DC PACVD deposition temperature, duty cycle, hydrogen flow and argon/CH4 flow ratio on the wear rate and durability of DLC films was studied. • Results show that wear rate of the DLC films, reduced from 14×E-4 mm3/Nm to 1×E-6 mm3/Nm with increasing the duty cycle from 50% to 80%. • In low duty cycle (around 50%), wear rate increases with increasing in Argon/CH4 flow ratio. • Oxidation, fatigue, abrasion and graphitization are main wear mechanisms in the DLC film. - Abstract: The effect of pulsed direct current (DC) plasma-assisted chemical vapor deposition (PACVD) parameters such as temperature, duty cycle, hydrogen flow, and argon/CH{sub 4} flow ratio on the wear behavior and wear durability of the diamond-like carbon (DLC) films was studied by using response surface methodology (RSM). DLC films were deposited on nitrocarburized AISI 4140 steel. Wear rate and wear durability of the DLC films were examined with the pin-on-disk method. Field emission scanning electron microscopy, Raman spectroscopy, and nanoindentation techniques were used for studying wear mechanisms, chemical structure, and hardness of the DLC films. RSM results show that duty cycle is one of the important parameters that affect the wear rate of the DLC samples. The wear rate of the samples deposited with a duty cycle of >75% decreases with an increase in the argon/CH4 ratio. In contrast, for a duty cycle of <65%, the wear rate increases with an increase in the argon/CH{sub 4} ratio. The wear durability of the DLC samples increases with an increase in the duty cycle, hydrogen flow, and argon/CH{sub 4} flow ratio at the deposition temperature between 85 °C and 110 °C. Oxidation, fatigue, abrasive wear, and graphitization are the wear mechanisms observed on the wear scar of the DLC samples deposited with the optimum deposition conditions.

Online Vce measurement method for wear-out monitoring of high power IGBT modules

DEFF Research Database (Denmark)

Beczkowski, Szymon; Ghimire, Pramod; de Vega, Angel Ruiz

2013-01-01

A simple Vce online monitoring circuit is presented in this paper. It allows an accurate wear out prediction of IGBT modules, in high-power applications, during normal converter operation. Bipolar measurement allows monitoring of both IGBT and antiparallel diode. The circuit uses two serial...... offset due to diodes' forward voltage temperature dependency. Using four diodes one can monitor voltages on all power devices in a converter leg....

Study on the friction and wear properties of glass fabric composites filled with nano- and micro-particles under different conditions

International Nuclear Information System (INIS)

Su Fenghua; Zhang Zhaozhu; Liu Weimin

2005-01-01

wear behaviors of the unfilled glass fabric and the composites. In a practical viewpoint, 10% PTFE-filled glass fabric composite could be suitable to tribological applications at moderately elevated temperature

Microstructural evolution during dry wear test in magnesium and Mg-Y alloy

Energy Technology Data Exchange (ETDEWEB)

Somekawa, Hidetoshi, E-mail: SOMEKAWA.Hidetoshi@nims.go.jp [Research Center for Strategic Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Maeda, Shunsuke; Hirayama, Tomoko; Matsuoka, Takashi [Department of Mechanical Engineering, Doshisha University, 1-3 Miyakodani, Tatara, Kyotanabe 610-0321 (Japan); Inoue, Tadanobu [Research Center for Strategic Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Mukai, Toshiji [Department of Mechanical Engineering, Kobe University, 1-1 Rokkodai, Kobe, 657-8501 (Japan)

2013-01-20

The friction and wear properties of pure magnesium and the Mg-Y alloy were investigated using the pin-on-disk configuration. The friction and wear resistance of the Mg-Y alloy was superior to those of pure magnesium. The wear mechanism was abrasion under all the conditions. The deformed microstructural evolutions near the surface region were observed by transmission electron microscopy and electron backscatter diffraction. The stress and strain states were also evaluated by finite element analysis (FEA). The deformed microstructures of both alloys consisted of the {l_brace}10-12{r_brace} twinning formation and the FEA results showed the occurrence of plastic deformation even at the beginning of the test. The formation of low angle grain boundaries was also confirmed with an increase in the applied load in the Mg-Y alloy. On the other hand, grain refinement due to dynamic recrystallization was observed in pure magnesium as the wear test progressed. The different microstructures resulted from difference in the surface temperature during the wear test, which was estimated to be around 393 K and 363 K for pure magnesium and the Mg-Y alloy, respectively. The high increment temperature in the fine-grained alloys brought about the occurrence of grain boundary sliding, i.e., material softening, which led to a decrease in the friction and wear properties. The present results indicated that one of the methods for enhancing the friction and wear properties is to increase the dynamic recrystallization temperature.

A rolling-gliding wear simulator for the investigation of tribological material pairings for application in total knee arthroplasty

Science.gov (United States)

2010-01-01

Background Material wear testing is an important technique in the development and evaluation of materials for use in implant for total knee arthroplasty. Since a knee joint induces a complex rolling-gliding movement, standardised material wear testing devices such as Pin-on-Disc or Ring-on-Disc testers are suitable to only a limited extent because they generate pure gliding motion only. Methods A rolling-gliding wear simulator was thus designed, constructed and implemented, which simulates and reproduces the rolling-gliding movement and loading of the knee joint on specimens of simplified geometry. The technical concept was to run a base-plate, representing the tibia plateau, against a pivoted cylindrical counter-body, representing one femur condyle under an axial load. A rolling movement occurs as a result of the friction and pure gliding is induced by limiting the rotation of the cylindrical counter-body. The set up also enables simplified specimens handling and removal for gravimetrical wear measurements. Long-term wear tests and gravimetrical wear measurements were carried out on the well known material pairings: cobalt chrome-polyethylene, ceramic-polyethylene and ceramic-ceramic, over three million motion cycles to allow material comparisons to be made. Results The observed differences in wear rates between cobalt-chrome on polyethylene and ceramic on polyethylene pairings were similar to the differences of published data for existing material-pairings. Test results on ceramic-ceramic pairings of different frontal-plane geometry and surface roughness displayed low wear rates and no fracture failures. Conclusions The presented set up is able to simulate the rolling-gliding movement of the knee joint, is easy to use, and requires a minimum of user intervention or monitoring. It is suitable for long-term testing, and therefore a useful tool for the investigation of new and promising materials which are of interest for application in knee joint replacement

A rolling-gliding wear simulator for the investigation of tribological material pairings for application in total knee arthroplasty

Directory of Open Access Journals (Sweden)

Denkena Berend

2010-06-01

Full Text Available Abstract Background Material wear testing is an important technique in the development and evaluation of materials for use in implant for total knee arthroplasty. Since a knee joint induces a complex rolling-gliding movement, standardised material wear testing devices such as Pin-on-Disc or Ring-on-Disc testers are suitable to only a limited extent because they generate pure gliding motion only. Methods A rolling-gliding wear simulator was thus designed, constructed and implemented, which simulates and reproduces the rolling-gliding movement and loading of the knee joint on specimens of simplified geometry. The technical concept was to run a base-plate, representing the tibia plateau, against a pivoted cylindrical counter-body, representing one femur condyle under an axial load. A rolling movement occurs as a result of the friction and pure gliding is induced by limiting the rotation of the cylindrical counter-body. The set up also enables simplified specimens handling and removal for gravimetrical wear measurements. Long-term wear tests and gravimetrical wear measurements were carried out on the well known material pairings: cobalt chrome-polyethylene, ceramic-polyethylene and ceramic-ceramic, over three million motion cycles to allow material comparisons to be made. Results The observed differences in wear rates between cobalt-chrome on polyethylene and ceramic on polyethylene pairings were similar to the differences of published data for existing material-pairings. Test results on ceramic-ceramic pairings of different frontal-plane geometry and surface roughness displayed low wear rates and no fracture failures. Conclusions The presented set up is able to simulate the rolling-gliding movement of the knee joint, is easy to use, and requires a minimum of user intervention or monitoring. It is suitable for long-term testing, and therefore a useful tool for the investigation of new and promising materials which are of interest for application in

A rolling-gliding wear simulator for the investigation of tribological material pairings for application in total knee arthroplasty.

Science.gov (United States)

Richter, Berna I; Ostermeier, Sven; Turger, Anke; Denkena, Berend; Hurschler, Christof

2010-06-15

Material wear testing is an important technique in the development and evaluation of materials for use in implant for total knee arthroplasty. Since a knee joint induces a complex rolling-gliding movement, standardised material wear testing devices such as Pin-on-Disc or Ring-on-Disc testers are suitable to only a limited extent because they generate pure gliding motion only. A rolling-gliding wear simulator was thus designed, constructed and implemented, which simulates and reproduces the rolling-gliding movement and loading of the knee joint on specimens of simplified geometry. The technical concept was to run a base-plate, representing the tibia plateau, against a pivoted cylindrical counter-body, representing one femur condyle under an axial load. A rolling movement occurs as a result of the friction and pure gliding is induced by limiting the rotation of the cylindrical counter-body. The set up also enables simplified specimens handling and removal for gravimetrical wear measurements. Long-term wear tests and gravimetrical wear measurements were carried out on the well known material pairings: cobalt chrome-polyethylene, ceramic-polyethylene and ceramic-ceramic, over three million motion cycles to allow material comparisons to be made. The observed differences in wear rates between cobalt-chrome on polyethylene and ceramic on polyethylene pairings were similar to the differences of published data for existing material-pairings. Test results on ceramic-ceramic pairings of different frontal-plane geometry and surface roughness displayed low wear rates and no fracture failures. The presented set up is able to simulate the rolling-gliding movement of the knee joint, is easy to use, and requires a minimum of user intervention or monitoring. It is suitable for long-term testing, and therefore a useful tool for the investigation of new and promising materials which are of interest for application in knee joint replacement implants.

An Experimental Investigation of Cutting Temperature and Tool Wear in 2 Dimensional Ultrasonic Vibrations Assisted Micro-Milling

Directory of Open Access Journals (Sweden)

Ibrahim Mohd Rasidi

2017-01-01

Full Text Available Two dimensional Ultrasonic vibration assisted milling (2D UVAM well knows process that involved in high tech system to generate ultra range of frequency applied to the milling process. More industries nowadays become aware taking this opportunity to improve their productivity without decreasing their product accuracies. This paper investigate a comparative machining between UVAM and conventional machining (CM in tool wear and cutting temperature in milling process. Micro amplitude and sine wave frequency will be generate into the workpiece jig by piezo-actuator. Thus, creating a micro gap that allow heat remove effectively with the chip produces. A more complex tool trajectory mechanics of 2D UVAM has been found during this research. The approaching the tool tip into the workpiece surfaces is affected by the amplitude displacement along the frequency applied. It is found that the tool wear was reduce and surface roughness improvement by applying the 2D UVAM compared to the CM when choosing the optimum amplitude and appropriate frequency.

Ceramic-like wear behaviour of human dental enamel.

Science.gov (United States)

Arsecularatne, J A; Hoffman, M

2012-04-01

This paper reports a transmission electron microscopy (TEM) analysis of subsurfaces of enamel specimens following in vitro reciprocating wear tests with an enamel cusp sliding on a flat enamel specimen under hydrated conditions. The obtained results show that crack formation occurred in the wear scar subsurface. The path followed by these cracks seems to be dictated either by the histological structure of enamel or by the contact stress field. Moreover, the analysis of a set of enamel wear results obtained from the literature and application of fracture-based models, originally developed for ceramics, correlate well, confirming the similar wear processes taking place in these materials. This analysis also reveals a marked influence of coefficient of friction on the enamel wear rate: for a higher coefficient of friction value, enamel wear can be severe even under forces generated during normal operation of teeth. Copyright © 2011 Elsevier Ltd. All rights reserved.

Optimization of pulsed DC PACVD parameters: Toward reducing wear rate of the DLC films

Science.gov (United States)

Ebrahimi, Mansoureh; Mahboubi, Farzad; Naimi-Jamal, M. Reza

2016-12-01

The effect of pulsed direct current (DC) plasma-assisted chemical vapor deposition (PACVD) parameters such as temperature, duty cycle, hydrogen flow, and argon/CH4 flow ratio on the wear behavior and wear durability of the diamond-like carbon (DLC) films was studied by using response surface methodology (RSM). DLC films were deposited on nitrocarburized AISI 4140 steel. Wear rate and wear durability of the DLC films were examined with the pin-on-disk method. Field emission scanning electron microscopy, Raman spectroscopy, and nanoindentation techniques were used for studying wear mechanisms, chemical structure, and hardness of the DLC films. RSM results show that duty cycle is one of the important parameters that affect the wear rate of the DLC samples. The wear rate of the samples deposited with a duty cycle of >75% decreases with an increase in the argon/CH4 ratio. In contrast, for a duty cycle of <65%, the wear rate increases with an increase in the argon/CH4 ratio. The wear durability of the DLC samples increases with an increase in the duty cycle, hydrogen flow, and argon/CH4 flow ratio at the deposition temperature between 85 °C and 110 °C. Oxidation, fatigue, abrasive wear, and graphitization are the wear mechanisms observed on the wear scar of the DLC samples deposited with the optimum deposition conditions.

Nitrogen implantation of steels: A treatment which can initiate sustained oxidative wear

International Nuclear Information System (INIS)

Hale, E.B.; Reinbold, R.; Missouri Univ., Rolla; Kohser, R.A.

1987-01-01

Falex wear tests on mild (SAE 3135) steel samples treated by either nitrogen implantation (2.5x10 17 N 2 + cm -2 at 180 keV) or low temperature (about 315 0 C) oxidation are reported. The results show that both treatments lead to about an order-of-magnitude reduction in the long-term wear rate of the steel. In addition to the wear rate measurements, the wear member asymmetry behavior, scanning electron microscopy studies, Auger spectra and sputter profiles all indicate that the wear modes induced by both treatments are the same and are oxidative wear. These results confirm the previously proposed initiator-sustainer wear model in which implanted nitrogen simply acts as an initiator of favorable oxidative wear but is not directly involved in maintaining the sustained wear resistance. Possible mechanisms for both the initiation process and the sustained wear process are reviewed and discussed. (orig.)

A Study on the Sliding/Impact Wear of a Nuclear Fuel Rod in Room Temperature Air: (I) Development of a Test Rig and Characteristic Analysis

International Nuclear Information System (INIS)

Lee, Young Ho; Lee, Kang Hee; Kim, Hyung Kyu

2007-01-01

A new type of a fretting wear tester has been designed and developed in order to simulate the actual vibration behavior of a nuclear fuel rod for springs/dimples in room temperature. When considering the actual contact condition between fuel rod and spring/dimple, if fretting wear progress due to the Flow-Induced Vibration (FIV) under a specific normal load exerted on the fuel rod by the elastic deformation of the spring, the contacting force between the fuel rod and dimple that were located in the opposite side should be decreased. Consequently, the evaluation of developed spacer grids against fretting wear damage should be performed with the results of a cell unit experiments because the contacting force is one of the most important variables that influence to the fretting wear mechanism. Therefore, it is necessary to develop a new type of fretting test rig in order to simulate the actual contact condition. In this paper, the development procedure of a new fretting wear tester and its performance were discussed in detail

Cutting tool wear monitoring with the use of impedance layers

OpenAIRE

Sadílek, Marek; Kratochvíl, Jiří; Petrů, Jana; Čep, Robert; Zlámal, Tomáš; Stančeková, Dana

2014-01-01

The article deals with problems of cutting process monitoring in real time. It is focused on tool wear by means of impedance layers applied on ceramic cutting inserts. In the experimental part the cutting process is monitored using electrical resistance measurement. The results are compared and verified using the monitored cutting temperature and tool wear. The testing of impedance layers is reasonable mainly for cutting edge diagnostics. The width of this layer determines the wear allowance ...

Contact Thermal Analysis and Wear Simulation of a Brake Block

Directory of Open Access Journals (Sweden)

Nándor Békési

2013-01-01

Full Text Available The present paper describes an experimental test and a coupled contact-thermal-wear analysis of a railway wheel/brake block system through the braking process. During the test, the friction, the generated heat, and the wear were evaluated. It was found that the contact between the brake block and the wheel occurs in relatively small and slowly moving hot spots, caused by the wear and the thermal effects. A coupled simulation method was developed including numerical frictional contact, transient thermal and incremental wear calculations. In the 3D simulation, the effects of the friction, the thermal expansion, the wear, and the temperature-dependent material properties were also considered. A good agreement was found between the results of the test and the calculations, both for the thermal and wear results. The proposed method is suitable for modelling the slowly oscillating wear caused by the thermal expansions in the contact area.

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.

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.

3D FEM Simulation of Flank Wear in Turning

Science.gov (United States)

Attanasio, Aldo; Ceretti, Elisabetta; Giardini, Claudio

2011-05-01

This work deals with tool wear simulation. Studying the influence of tool wear on tool life, tool substitution policy and influence on final part quality, surface integrity, cutting forces and power consumption it is important to reduce the global process costs. Adhesion, abrasion, erosion, diffusion, corrosion and fracture are some of the phenomena responsible of the tool wear depending on the selected cutting parameters: cutting velocity, feed rate, depth of cut, …. In some cases these wear mechanisms are described by analytical models as a function of process variables (temperature, pressure and sliding velocity along the cutting surface). These analytical models are suitable to be implemented in FEM codes and they can be utilized to simulate the tool wear. In the present paper a commercial 3D FEM software has been customized to simulate the tool wear during turning operations when cutting AISI 1045 carbon steel with uncoated tungsten carbide tip. The FEM software was improved by means of a suitable subroutine able to modify the tool geometry on the basis of the estimated tool wear as the simulation goes on. Since for the considered couple of tool-workpiece material the main phenomena generating wear are the abrasive and the diffusive ones, the tool wear model implemented into the subroutine was obtained as combination between the Usui's and the Takeyama and Murata's models. A comparison between experimental and simulated flank tool wear curves is reported demonstrating that it is possible to simulate the tool wear development.

Tool wear of a single-crystal diamond tool in nano-groove machining of a quartz glass plate

International Nuclear Information System (INIS)

Yoshino, Masahiko; Nakajima, Satoshi; Terano, Motoki

2015-01-01

Tool wear characteristics of a diamond tool in ductile mode machining are presented in this paper. Nano-groove machining of a quartz glass plate was conducted to examine the tool wear rate of a single-crystal diamond tool. Effects of lubrication on the tool wear rate were also evaluated. A numerical simulation technique was developed to evaluate the tool temperature and normal stress acting on the wear surface. From the simulation results it was found that the tool temperature does not increase during the machining experiment. It is also demonstrated that tool wear is attributed to the abrasive wear mechanism, but the effect of the adhesion wear mechanism is minor in nano-groove machining. It is found that the tool wear rate is reduced by using water or kerosene as a lubricant. (paper)

Application and analysis of palladium vapor deposited on stainless steel for high temperature electrical contacts

International Nuclear Information System (INIS)

Jodeh, S.

2008-01-01

Using electron beam evaporation. Pd thin films of 300 nm thickness have been deposited on 301 stainless steel for high temperature electrical contact studies. The structure and compost ion of the helms were studied in detail x-ray diffraction (XRD), scanning electron microscopy (Sem), electron probe microanalysis (EPMA), and x-ray photoelectron spectroscopy (XP S) with sputter depth profiling. The contact properties such as contact resistance, fretting wear resistance, and thermal stability have been measured.The contact resistance rem ins low after heat-aging in air for 168 h at 150 and 200 deg., but increases significantly after heat-aging at 340 deg.. This increase in contact resistance is caused by the formation of about a 27 nm (1 μin.) thick Pdo. In contrast, the thickness of the Pdo is too thin to cause measurable contact resistance increases after heat-aging at 150 and 200 deg.. The fretting wear resistance of Pd coated 301 stainless steel is better than that of electroplated Sn of ser veal thousand nm thickness. Thus, vapor deposited Pd coating on 301 stainless steel may replace electroplated Sn for electrical contact application at elevated temperatures.

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.

A thermal, thermoelastic, and wear analysis of high-energy disk brakes

Science.gov (United States)

Kennedy, F. E., Jr.; Wu, J. J.; Ling, F. F.

1974-01-01

A thermomechanical investigation of the sliding contact problem encountered in high-energy disk brakes is described. The analysis includes a modelling, using the finite element method of the thermoelastic instabilities that cause transient changes in contact area to occur on the friction surface. In order to include the effect of wear at the contact surface, a wear criterion is proposed that results in the prediction of wear rates for disk brakes that are quite close to experimentally determined wear rates. The thermal analysis shows that the transient temperature distribution in a disk brake assembly can be determined more accurately by use of this thermomechanical analysis than by a more conventional analysis that assumes constant contact conditions. It also shows that lower, more desirable, temperatures in disk brakes can be attained by increasing the volume, the thermal conductivity, and, especially, the heat capacity of the brake components.

Nano- and Macro-wear of Bio-carbo-nitrided AISI 8620 Steel Surfaces

Science.gov (United States)

Arthur, Emmanuel Kwesi; Ampaw, Edward; Zebaze Kana, M. G.; Adetunji, A. R.; Olusunle, S. O. O.; Adewoye, O. O.; Soboyejo, W. O.

2015-12-01

This paper presents the results of an experimental study of nano- and macro-scale wear in a carbo-nitrided AISI 8620 steel. Carbo-nitriding is carried out using a novel method that involves the use of dried, cyanide-containing cassava leaves, as sources of carbon and nitrogen. These are used in a pack cementation that is used to diffuse carbon and nitrogen into case layers at intermediate temperatures [673.15 K, 723.15 K, 773.15 K, and 823.15 K (400 °C, 450 °C, 500 °C, and 550 °C)]. Nano- and macro-scale wear properties are studied in the case-hardened surfaces, using a combination of nano-scratch and pin-on-disk experiments. The measured wear volumes (at both nano- and macro-length scales) are shown to increase with decreasing pack cyaniding temperature. The nano- and macro-wear resistances are also shown to be enhanced by the in situ diffusion of carbon and nitrogen from cyanide-containing bio-processed waste. The underlying wear mechanisms are also elucidated via atomic force microscopy and scanning electron microscopy observations of the wear tracks. The implications of the results are discussed for the design of hardened carbo-nitrided steel surfaces with improved wear resistance.

Effect of plasma spraying parameter on wear resistance of NiCrBSiCFe plasma coatings on austenitic stainless steel at elevated temperatures at various loads

International Nuclear Information System (INIS)

Parthasarathi, N.L.; Duraiselvam, Muthukannan; Borah, Utpal

2012-01-01

Highlights: ► Effect of plasma spraying parameters, especially the stand-off distance. ► Effect of microstructure and applied load on coating in sliding wear. ► The reason for maximum wear rate at 250 °C and the minimum wear at 350 °C were explained. ► The worn debris were characterised by SEM analysis and correlated with wear rate. -- Abstract: The dry sliding wear tests were carried out on AISI 316 austenitic stainless steel (ASS) plasma coated with NiCrBSiCFe alloy powder under two set of plasma spraying parameters (PSP-1 and PSP-2). EN 8 medium carbon steel was used as a counterface material. The tests were carried out at loads of 20 N and 40 N with a constant sliding velocity of 1 m/s at room temperature (35°), 150 °C, 250 °C and 350 °C. Metallographic characterisation was carried out by optical microscope (OM), scanning electron microscope (SEM) and X-ray diffraction (XRD). Between the two plasma parameters tested, stand-off distance of 125 mm was found to be more suitable for producing uniform lamellar microstructure with fewer amounts of pores which shows better wear resistance. The wear rate at 250 °C was comparatively more due to the material softening and adhesion by intermolecular bonding. The worn debris collected during sliding at 350 °C turn into oxides which further behaves like a protective and lubricative film eliminating the chances of severe material loss. SEM was used to characterise the worn track and debris to identity the wear mechanism.

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.

The synergism of impact wear and oxidation in carbon dioxide environments

International Nuclear Information System (INIS)

Morri, J.R.

1987-01-01

The impact fretting wear characteristics in Co 2 of a 9%Cr steel against a 310SS counterface have been studied between 100 0 and 500 0 C. An energy effect was identified in which high energy impacts suppressed a severe-to-mild wear transition for low energy impacts between 250 0 and 350 0 C. In addition a severe form of high temperature wear (above 400 0 C) was observed in which pitting of the 9Cr steel and transfer to the 310SS occurred. Subsequent wear scar examination revealed a wear mechanism dominated by the interaction of the oxidation characteristics and the changing mechanical behaviour of the 9Cr. (author)

Surface effects in adhesion, friction, wear, and lubrication

National Research Council Canada - National Science Library

Buckley, Donald H

1981-01-01

... for carbon bodies to improve their wear resistance in high altitude aircraft generator applications. Basic researchers found that moisture in the carbon was critical t o its lubrication. Therefore, the presence of moisture o n the surface of the carbon was important. With it present, the carbon lubricated very effectively and very low wear was ...

Towards the effective tool wear control in micro-EDM milling

DEFF Research Database (Denmark)

Bissacco, Giuliano; Valentincic, J.; Hansen, Hans Nørgaard

2010-01-01

The electrode wear in micro-electrical discharge milling (micro-EDM milling) is one of the main problems to be solved in order to improve machining accuracy. This paper presents an investigation on wear and material removal in micro-EDM milling for selected process parameter combinations typical...... of the accuracy of volume measurements on the electrode wear per discharge and on the material removal per discharge are discussed, and the issues limiting the applicability of real time wear sensing in micro-EDM milling are presented....

Tribological Properties of a Pennzane(Registered Trademark)-Based Liquid Lubricant (Disubstituted Alkylated Cyclopentane) for Low Temperature Space Applications

Science.gov (United States)

Venier, Clifford; Casserly, Edward W.; Jones, William R., Jr.; Marchetti, Mario; Jansen, Mark J.; Predmore, Roamer E.

2002-01-01

The tribological properties of a disubstituted alkylated cyclopentane, Pennzane (registered) Synthesized Hydrocarbon Fluid X-1000, are presented. This compound is a lower molecular weight version of the commonly used multiply alkylated cyclopentane, Pennzane X-2000, currently used in many space mechanisms. New, lower temperature applications will require liquid lubricants with lower viscosities and pour points and acceptable vapor pressures. Properties reported include: friction and wear studies and lubricated lifetime in vacuum; additionally, typical physical properties (i.e., viscosity-temperature, pour point, flash and fire point, specific gravity, refractive index, thermal properties, volatility and vapor pressure) are reported.

Dental wear, wear rate, and dental disease in the African apes.

Science.gov (United States)

Elgart, Alison A

2010-06-01

The African apes possess thinner enamel than do other hominoids, and a certain amount of dentin exposure may be advantageous in the processing of tough diets eaten by Gorilla. Dental wear (attrition plus abrasion) that erodes the enamel exposes the underlying dentin and creates additional cutting edges at the dentin-enamel junction. Hypothetically, efficiency of food processing increases with junction formation until an optimal amount is reached, but excessive wear hinders efficient food processing and may lead to sickness, reduced fecundity, and death. Occlusal surfaces of molars and incisors in three populations each of Gorilla and Pan were videotaped and digitized. The quantity of incisal and molar occlusal dental wear and the lengths of dentin-enamel junctions were measured in 220 adult and 31 juvenile gorilla and chimpanzee skulls. Rates of dental wear were calculated in juveniles by scoring the degree of wear between adjacent molars M1 and M2. Differences were compared by principal (major) axis analysis. ANOVAs compared means of wear amounts. Pearson correlation coefficients were calculated to compare the relationship between molar wear and incidence of dental disease. Results indicate that quantities of wear are significantly greater in permanent incisors and molars and juvenile molars of gorillas compared to chimpanzees. The lengths of dentin-enamel junctions were predominantly suboptimal. Western lowland gorillas have the highest quantities of wear and the most molars with suboptimal wear. The highest rates of wear are seen in Pan paniscus and Pan t. troglodytes, and the lowest rates are found in P.t. schweinfurthii and G. g. graueri. Among gorillas, G. b. beringei have the highest rates but low amounts of wear. Coefficients between wear and dental disease were low, but significant when all teeth were combined. Gorilla teeth are durable, and wear does not lead to mechanical senescence in this sample.

Study of wear performance of deep drawing tooling

Science.gov (United States)

Naranje, Vishal G.; Karthikeyan, Ram; Nair, Vipin

2017-09-01

One of the most common challenges for many of the mechanical engineers and also in the field of materials science is the issue of occurrences of wear of the material parts which is used in certain applications that involves such surface interactions. In this paper, wear behaviour of particular grade High Carbon High Chromium Steel and many most famously D2, H13, O1 known as the Viking steel has been studied, evaluated and analyzed under certain processing parameters such as speed, load, track diameter and time required for deep drawing process to know it’s the wear rate and coefficient of friction. Also, the significance of the processing parameters which is used for wear testing analysis is also examined.

The influence of reciprocating sliding wear on the oxidation behaviour of Fe-12Cr steel

International Nuclear Information System (INIS)

Smith, A.F.

1989-01-01

Medium-chromium ferritic alloys are used extensively in advanced gas cooled reactors (AGRs). Under certain conditions these alloys can undergo breakaway oxidation in which the rate-limiting step is located at the oxide/metal interface rather than the more usual gas/oxide interface; this results in linear oxidation kinetics. Repeated removal of oxide layers can expose chromium-depleted metal to the oxidizing gas and promote nucleation of breakaway oxidation. The question has been addressed as to whether high temperature sliding wear processes can also disrupt the surface so as to make the material potentially susceptible to breakaway oxidation. High temperature reciprocating wear tests of Fe-12Cr material in both low and high pressure reactor gas have been carried out. As expected, compact adhesive load-bearing oxide and mixed oxide/metal beds form in wear regions. These contacting features wear at very low rates of less than 10 -16 m 3 (Nm) -1 . Preformed oxides wear at sufficiently low rates at high temperature as to preclude the possibility of exposure of the underlying metal to the reactor gas. It is thus unlikely that sliding wear processes will accelerate the tendency for initiation of breakaway oxidation. (author)

Microstructure and wear resistance of spray-formed supermartensitic stainless steel

Directory of Open Access Journals (Sweden)

Guilherme Zepon

2013-06-01

Full Text Available Since the early 90's the oil industry has been encouraging the development of corrosion and wear resistant alloys for onshore and offshore pipeline applications. In this context supermartensitic stainless steel was introduced to replace the more expensive duplex stainless steel for tubing applications. Despite the outstanding corrosion resistance of stainless steels, their wear resistance is of concern. Some authors reported obtaining material processed by spray forming, such as ferritic stainless steel, superduplex stainless steel modified with boron, and iron-based amorphous alloys, which presented high wear resistance while maintaining the corrosion performance1,2. The addition of boron to iron-based alloys promotes the formation of hard boride particles (M2B type which improve their wear resistances3-9. This work aimed to study the microstructure and wear resistance of supermartensitic stainless steel modified with 0.3 wt. (% and 0.7 wt. (% processed by spray forming (SF-SMSS 0.3%B and SF-SMSS 0.7%B, respectively. These boron contents were selected in order to improve the wear resistance of supermartensitic stainless steel through the formation of uniformly distributed borides maintaining the characteristics of the corrosion resistant matrix. SF-SMSS 0.7%B presents an abrasive wear resistance considerably higher than spray-formed supermartensitic stainless steel without boron addition (SF-SMSS.

Wear reduction through piezoelectrically-assisted ultrasonic lubrication

International Nuclear Information System (INIS)

Dong, Sheng; J Dapino, Marcelo

2014-01-01

Traditional lubricants are undesirable in harsh aerospace environments and certain automotive applications. Ultrasonic vibrations can be used to reduce and modulate the effective friction coefficient between two sliding surfaces. This paper investigates the relationship between friction force reduction and wear reduction in ultrasonically lubricated surfaces. A pin-on-disc tribometer is modified through the addition of a piezoelectric transducer which vibrates the pin at 22 kHz in the direction perpendicular to the rotating disc surface. Friction and wear metrics including volume loss, surface roughness, friction forces and apparent stick-slip effects are measured without and with ultrasonic vibrations at three different sliding velocities. SEM imaging and 3D profilometry are used to characterize the wear surfaces and guide model development. Over the range of speeds considered, ultrasonic vibrations reduce the effective friction force up to 62% along with a wear reduction of up to 49%. A simple cube model previously developed to quantify friction force reduction is implemented which describes wear reduction within 15% of the experimental data. (paper)

Wear of human enamel: a quantitative in vitro assessment.

Science.gov (United States)

Kaidonis, J A; Richards, L C; Townsend, G C; Tansley, G D

1998-12-01

Many factors influence the extent and rate at which enamel wears. Clinical studies in humans are limited by difficulties in the accurate quantification of intra-oral wear and by a lack of control over the oral environment. The purpose of this study was to determine the wear characteristics of human dental enamel under controlled experimental conditions. An electro-mechanical tooth wear machine, in which opposing enamel surfaces of sectioned, extracted teeth were worn under various conditions, was used to simulate tooth grinding or bruxism. Enamel surface wear was quantified by weight to an accuracy of 0.1 mg, with water uptake and loss controlled. The variables considered included the structure and hardness of enamel, facet area, duration of tooth contact, relative speed of opposing surfaces, temperature, load, pH, and the nature of the lubricant. Enamel wear under non-lubricated conditions increased with increasing load over the range of 1.7 to 16.2 kg. The addition of a liquid lubricant (pH = 7) reduced enamel wear up to 6.7 kg, but when the load increased above this threshold, the rate of wear increased dramatically. With the viscosity of the lubricant constant and pH = 3, the rate of wear was further reduced to less than 10% of the non-lubricated rate at 9.95 kg, after which the rate again increased substantially. Under more extreme conditions (pH = 1.2, simulating gastric acids), the wear was excessive under all experimental loads. When saliva was used as a lubricant, the amount of wear was relatively low at 9.95 kg, but rapid wear occurred at 14.2 kg and above. These results indicate that under non-lubricated conditions, enamel wear remains low at high loads due to the dry-lubricating capabilities of fine enamel powder. Under lubricated conditions, low loads with an acidic lubricant lead to little enamel wear, whereas very low pH results in a high rate of wear under all loads.

Overview of PVD wear resistant coatings

International Nuclear Information System (INIS)

Teeter, F.J.

1999-01-01

The combined functionality of wear-resistant and low-friction multilayer coatings has widened application possibilities for a new generation of coated tools. For the first time tool wear mechanisms are comprehensively addressed both at the cutting edge and contact areas away from the edge where chip evacuation is facilitated. Since its recent market introduction a combined TiA1N and WC/C PVD coating has been proven to increase cutting performance in various metal cutting operations, notably drilling and tapping of steels and aluminum alloys. Significant improvements have been obtained under dry as well as with coolant conditions. The results of laboratory metal cutting tests and field trials to date will be described. Correlations between chip formation / wear mechanisms and coating properties are given to explain the effectiveness of this coating. (author)

Fretting wear damage of steam generator tubes and its prediction modeling

International Nuclear Information System (INIS)

Che Honglong; Lei Mingkai

2013-01-01

The steam generator is the key equipment used for the energy transition in nuclear power plant. Since the high-temperature and high-pressure fluid flows with high speed, the steam generator tubes will be excited and vibrate, leading to the tremendous fretting wear problem on the tubes, sometimes even leading to tube cracking. This paper introduces typical fretting wear cases, the result of corresponding simulation wear experiment and damage mechanism which combining mechanical wear and erosion-corrosion. Work rate model could give a reasonable life prediction about the steam generator tube, and this predictive model has been used in nuclear power plant safety assessment. (authors)

Tribological properties of multifunctional coatings with Shape Memory Effect in abrasive wear

Science.gov (United States)

Blednova, Zh. M.; Dmitrenko, D. V.; Balaev, E. U. O.

2018-01-01

The article gives research results of the abrasive wear process on samples made of Steel 1045, U10 and with applied composite surface layer "Nickel-Multicomponent material with Shape Memory Effect (SME) based on TiNi". For the tests we have chosen TiNiZr, which is in the martensite state and TiNiHfCu, which is in the austenitic state at the test temperature. The formation of the surface layer was carried out by high-speed oxygen-fuel deposition in a protective atmosphere of argon. In the wear test, Al2O3 corundum powder was used as an abrasive. It is shown that the wear rate of samples with a composite surface layer of multicomponent materials with SME is significantly reduced in comparison with the base, which is explained by reversible phase transformations of the surface layer with SME. After carrying out the additional surface plastic deformation (SPD), the resistance of the laminated composition to abrasion wear has greatly enhanced, due to the reinforcing effect of the SPD. It is recommended for products working in conditions of abrasive wear and high temperatures to use the complex formation technology of the surface composition "steel-nickel-material with high-temperature SME", including preparation of the substrate surface and the deposited material, high-speed spraying in the protective atmosphere of argon, followed by SPD.

Wear of Spur Gears Having a Dithering Motion and Lubricated with a Perfluorinated Polyether Grease

Science.gov (United States)

Krantz, Timothy; Oswald, Fred; Handschuh, Robert

2007-01-01

Gear contact surface wear is one of the important failure modes for gear systems. Dedicated experiments are required to enable precise evaluations of gear wear for a particular application. The application of interest for this study required evaluation of wear of gears lubricated with a grade 2 perfluorinated polyether grease and having a dithering (rotation reversal) motion. Experiments were conducted using spur gears made from AISI 9310 steel. Wear was measured using a profilometer at test intervals encompassing 10,000 to 80,000 cycles of dithering motion. The test load level was 1.1 GPa maximum Hertz contact stress at the pitch-line. The trend of total wear as a function of test cycles was linear, and the wear depth rate was approximately 1.2 nm maximum wear depth per gear dithering cycle. The observed wear rate was about 600 times greater than the wear rate for the same gears operated at high speed and lubricated with oil.

Wear Characterization of Aluminium/Basalt Fiber Reinforced Metal Matrix Composites - A Novel Material

Directory of Open Access Journals (Sweden)

P. Amuthakkannan

2017-06-01

Full Text Available Aluminum alloy based metal matrix composite participate have a wider applications in wear resistance applications. Attempt made in current study is that, basalt fiber reinforced aluminum metal matrix composite have been prepared using stir casting method. Different weight percentage of basalt fiber reinforced with Al (6061 metal matrix composites are used to study the wear resistance of the composites. For wear study, percentage of reinforcement, normal load and sliding velocity are the considered as important parameters. To study the effect of basalt fiber reinforcement on the dry sliding wear of Al6061 alloy composites the Pin On wear tester is used. Initially hardness of the composites was tested, it was found that increasing reinforcement in the composite hardness value of the composites also increased. Based on the Grey relation analysis (GRA the effects of wear resistance of the composites were studied.

Sliding wear and friction behavior of zirconium alloy with heat-treated Inconel718

Energy Technology Data Exchange (ETDEWEB)

Kim, J.H., E-mail: kimjhoon@cnu.ac.kr [Dept. of Mechanical Design Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Park, J.M. [Dept. of Mechanical Design Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Park, J.K.; Jeon, K.L. [Nuclear Fuel Technology Department, Korea Nuclear Fuel, 1047 Daedukdae-ro, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

2014-04-01

In water-cooled nuclear reactors, the sliding of fuel rod can lead to severe wear and it is an important issue to sustain the structural integrity of nuclear reactor. In the present study, sliding wear behavior of zirconium alloy in dry and water environment using Pin-On-Disk sliding wear tester was investigated. Wear resistance of zirconium alloy against heat-treated Inconel718 pin was examined at room temperature. Sliding wear tests were carried out at different sliding distance, axial load and sliding speed based on ASTM (G99-05). The results of these experiments were verified with specific wear rate and coefficient of friction. The micro-mechanisms responsible for wear in zirconium alloy were identified to be microcutting and microcracking in dry environment. Moreover, micropitting and delamination were observed in water environment.

Abrasive wear mechanisms and surface layer structure of refractory materials after mechanical working

International Nuclear Information System (INIS)

Milman, Y.V.; Lotsko, D.V.

1989-01-01

The mechanisms of abrasive wear and surface layer structure formation after different kinds of mechanical working are considered in terms of fracture and plastic deformation mechanisms for various refractory materials. The principles for classification of abrasive wear mechanisms are proposed, the four types of wear mechanisms are distinguished for various combinations of fractures and plastic deformation types. The concept of characteristic deformation temperature t * (knee temperature) is used. Detailed examples are given of investigating the surface layer structures in grinded crystals of sapphire and molybdenum. The amorphisation tendency of the thinnest surface layer while mechanical polishing is discussed separately. 19 refs., 11 figs., 2 tabs. (Author)

Assessment of wear dependence parameters in complex model of cutting tool wear

Science.gov (United States)

Antsev, A. V.; Pasko, N. I.; Antseva, N. V.

2018-03-01

This paper addresses wear dependence of the generic efficient life period of cutting tools taken as an aggregate of the law of tool wear rate distribution and dependence of parameters of this law's on the cutting mode, factoring in the random factor as exemplified by the complex model of wear. The complex model of wear takes into account the variance of cutting properties within one batch of tools, variance in machinability within one batch of workpieces, and the stochastic nature of the wear process itself. A technique of assessment of wear dependence parameters in a complex model of cutting tool wear is provided. The technique is supported by a numerical example.

Obtention, machining and wear of sintered alloys for automotive applications

International Nuclear Information System (INIS)

Jesus Filho, Edson Souza de

2006-01-01

The aim of this work was the development of materials for automotive applications, in particular, valve seat inserts for gasoline combustion engines. The development involved the following activities: processing by powder metallurgy techniques, heat treatment, mechanical and microstructural characterization, machining and wear of materials. This work was undertaken aiming cost reduction of this component by the use of cheaper and less pollutant elements, eliminating the presence of Co and Pb due to their high cost and toxicological effects, respectively. The accomplishment of a thorough research into patents revealed that the materials studied here present particular compositions and were not yet produced. The results of hardness measurements and the transverse radial strength of the studied materials, after heat treatment, revealed superior properties than the commercial alloys applied at the moment. The machining tests of the material without heat treatment indicated a similar behaviour in comparison to the commercial alloy, suggesting that the new alloy chemistry composition was not deleterious in this sense. After heat treatment, the obtained alloys presented a cutting force increase in relation to the commercial alloy. Wear tests results of heat treated materials presented smaller friction coefficient and mass loss than the commercial alloy, in ali cases. This was especially achieved due to the advantages offered by heat treatment allied to the addition of NbC and Ti/W carbides. The materials obtained here showed to be potential candidates to substitute with advantages, valve seat inserts made of Fe-Co alloys for gasoline combustion engines. (author)

Internal Diameter HVAF Spraying for Wear and Corrosion Applications

Science.gov (United States)

Lyphout, C.; Björklund, S.

2015-01-01

Electrolytic hard chrome (EHC) methods are still widely utilized in the printing, automotive and off-shore industries. Alternative methods to EHC have been widely developed in the past decade by conventional HVOF processes and more recently HVAF systems, which are processing at higher kinetic energy and more particularly at lower temperature, significantly increasing wear and corrosion resistance properties. A dedicated internal diameter HVAF system is here presented, and coatings characteristics are compared to the one obtained by standard HVAF coatings. Specially R&D designed fixtures with inside bore of 200 mm have been manufactured for this purpose, with a possibility to spray samples at increasing depth up to 400 mm while simulating closed bottom bore spraying. WC-based and Cr3C2-based powder feedstock materials have been deposited onto high-strength steel substrates. Respective coating microstructures, thermally induced stresses and corrosion resistance are discussed for further optimization of coating performances. The fact that the ID-HVAF system is utilized both for spraying and gritblasting procedures is also given a particular interest.

Characterization and wear performance of boride phases over tool steel substrates

Directory of Open Access Journals (Sweden)

Edgar E Vera Cárdenas

2016-02-01

Full Text Available This research work was conducted to characterize boride phases, obtained from the powder-pack process, on AISI H13 and D2 steel substrates, and investigate their tribological behavior. The boriding was developed at a temperature of 1273 K with an exposure time of 8 h. X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were conducted on the borided material to characterize the presence of the FeB, Fe2B, and CrB phases and the distribution of heavy elements on the surface of the substrates. The adherence of the boride layers was evaluated, in a qualitative form, through the Daimler-Benz Rockwell-C indentation technique. Sliding wear tests were then performed using a reciprocating wear test machine. All tests were conducted in dry conditions at room temperature. A frequency of 10 Hz and 15-mm sliding distance were used. The applied Hertzian pressure was 2.01 GPa. Scanning electron microscopy was used to observe and analyze the wear mechanisms. Additionally, the variation of the friction coefficient versus the number of cycles was obtained. Experimental results showed that the characteristic wear mechanism for the borided surface was plastic deformation and mild abrasive wear; for unborided substrates, cracking and spalling were observed.

Reconstruction mechanisms of tantalum oxide coatings with low concentrations of silver for high temperature tribological applications

Energy Technology Data Exchange (ETDEWEB)

Stone, D. S.; Bischof, M.; Aouadi, S. M., E-mail: samir.aouadi@unt.edu [Department of Material Science and Engineering, University of North Texas, Denton, Texas 76207 (United States); Gao, H.; Martini, A. [School of Engineering, University of California Merced, Merced, California 95343 (United States); Chantharangsi, C.; Paksunchai, C. [Department of Physics, King Mongkut' s University of Technology Thonburi, Bangkok 10140 (Thailand)

2014-11-10

Silver tantalate (AgTaO{sub 3}) coatings have been found to exhibit outstanding tribological properties at elevated temperatures. To understand the mechanisms involved in the tribological behavior of the Ag-Ta-O system, tantalum oxide coatings with a small content of silver were produced to investigate the metastable nature of this self-lubricating material. The coatings were produced by unbalanced magnetron sputtering, ball-on-disk wear tested at 750 °C, and subsequently characterized by X-ray diffraction, Scanning Auger Nanoprobe, cross-sectional Scanning Electron Microscopy, and Transmission Electron Microscopy. Complementary molecular dynamic simulations were carried out to investigate changes in the chemical and structural properties at the interface due to sliding for films with varying silver content. Both the experimental characterization and the theoretical modeling showed that silver content affects friction and wear, through the role of silver in film reconstruction during sliding. The results suggest that the relative amount of silver may be used to tune film performance for a given application.

Reconstruction mechanisms of tantalum oxide coatings with low concentrations of silver for high temperature tribological applications

International Nuclear Information System (INIS)

Stone, D. S.; Bischof, M.; Aouadi, S. M.; Gao, H.; Martini, A.; Chantharangsi, C.; Paksunchai, C.

2014-01-01

Silver tantalate (AgTaO 3 ) coatings have been found to exhibit outstanding tribological properties at elevated temperatures. To understand the mechanisms involved in the tribological behavior of the Ag-Ta-O system, tantalum oxide coatings with a small content of silver were produced to investigate the metastable nature of this self-lubricating material. The coatings were produced by unbalanced magnetron sputtering, ball-on-disk wear tested at 750 °C, and subsequently characterized by X-ray diffraction, Scanning Auger Nanoprobe, cross-sectional Scanning Electron Microscopy, and Transmission Electron Microscopy. Complementary molecular dynamic simulations were carried out to investigate changes in the chemical and structural properties at the interface due to sliding for films with varying silver content. Both the experimental characterization and the theoretical modeling showed that silver content affects friction and wear, through the role of silver in film reconstruction during sliding. The results suggest that the relative amount of silver may be used to tune film performance for a given application

Investigation on wear behavior of graphite baII under different pneumatic conveying environments

International Nuclear Information System (INIS)

Chen Zhipeng; Zheng Yanhua; Shi Lei; Yu Suyuan

2014-01-01

An experimental platform was built in the Institute of Nuclear and New Energy Technology (INET) to investigate the wear behavior of the graphite ball under the operational condition of the high temperature gas-cooled reactor (HTGR) fuel handling system. In this experimental platform, a series of experiments were carried out under different pneumatic conveying environments with the graphite balls, which were made of the material same as the fuel element matrix graphite (A3) of the 10 MW high temperature gas cooled reactor (HTR-10). The effect of the pneumatic conveying condition on the wear rate of graphite ball has been investigated, and the results include: (1) There is an obvious linear relationship between the wear rate and the feeding velocity of graphite ball elevated in the stainless steel elevating tube, and the wear rate will increase with the increase of the feeding velocity. (2) The wear rate of graphite ball under helium environment is significantly greater than that under air and nitrogen environments, which is caused by the different effects of various gas environments on mechanical properties of graphite. (author)

Wear behaviour and morphology of stir cast aluminium/SiC nanocomposites

Science.gov (United States)

Tanwir Alam, Md; Arif, Sajjad; Husain Ansari, Akhter

2018-04-01

Wear and friction play a vital role in the service life of components. Aluminium matrix nanocomposites possess tremendous potential for a number of applications in addition to their present uses. It is valuable to the field of newer materials for better performance in tribological applications. In this work, dry sliding wear, friction coefficient and morphology of aluminium alloy (A356) reinforced with silicon carbide nanoparticles (SiCn) were investigated. A356/SiCn nanocomposites (AMNCs) containing 1–5 weight percentage of SiCn were prepared through two-step stir casting process via mechanical ball milling. The wear test was conducted on pin-on-disc test apparatus. Regression analysis was performed to develop mathematical functions to fit the experimental data points. Morphological studies of Al and SiCn as-received, wear debris and worn surfaces were further analysed by SEM along with EDS. The occurrence of oxide layers was observed on worn surfaces. Iron trace was identified by wear debris. It was found that the wear loss and friction coefficient were strongly influenced by mechanical milling and SiCn content. The results exhibited that the friction coefficient reduces with the addition of SiCn as well as with the increase in load. However, wear resistance increases as the reinforcement content increases because of the embedding and wettability effects.

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.

Tribology of selected ceramics at temperatures to 900 C

Science.gov (United States)

Sliney, H. E.; Jacobson, T. P.; Deadmore, D.; Miyoshi, K.

1986-01-01

Results of fundamental and focused research on the tribological properties of ceramics are discussed. The basic friction and wear characteristics are given for ceramics of interest for use in gas turbine, adiabatic diesel, and Stirling engine applications. The importance of metal oxides in ceramic/metal sliding combinations is illustrated. The formulation and tribological additives are described. Friction and wear data are given for carbide and oxide-based composite coatings for temperatures to at least 900 C.

Resistance of superhydrophobic and oleophobic surfaces to varied temperature applications on 316L SS

Science.gov (United States)

Shams, Hamza; Basit, Kanza; Saleem, Sajid; Siddiqui, Bilal A.

316L SS also called Marine Stainless Steel is an important material for structural and marine applications. When superhydrophobic and oleophobic coatings are applied on 316L SS it shows significant resistance to wear and corrosion. This paper aims to validate the coatings manufacturer's information on optimal temperature range and test the viability of coating against multiple oil based cleaning agents. 316L SS was coated with multiple superhydrophic and oleohobic coatings and observed under SEM for validity of adhesion and thickness and then scanned under FFM to validate the tribological information. The samples were then dipped into multiple cleaning agents maintained at the range of operating temperatures specified by the manufacturer. Coating was observed for deterioration over a fixed time intervals through SEM and FFM. A comparison was drawn to validate the most critical cleaning agent and the most critical temperature at which the coating fails to leave the base substrate exposed to the environment.

Low Friction and Wear Surface for Application over a Wide Range of Temperature

National Research Council Canada - National Science Library

Bhattacharya, Rabi

1997-01-01

...) and Transmission electron microscopy (TEM), both before and after exposure to high temperatures (up to 700 deg C) in air. Friction measurements were performed at temperatures in the range of room temperature to 700 deg C in air...

Perspectives from the Wearable Electronics and Applications Research (WEAR) Lab, NASA, Johnson Space Center

Science.gov (United States)

Moses, Haifa R.

2017-01-01

As NASA moves beyond exploring low earth orbit and into deep space exploration, increased communication delays between astronauts and earth drive a need for crew to become more autonomous (earth-independent). Currently crew on board the International Space Station (ISS) have limited insight into specific vehicle system performance because of the dependency on monitoring and real-time communication with Mission Control. Wearable technology provides a method to bridge the gap between the human (astronaut) and the system (spacecraft) by providing mutual monitoring between the two. For example, vehicle or environmental information can be delivered to astronauts through on-body devices and in return wearables provide data to the spacecraft regarding crew health, location, etc. The Wearable Electronics and Applications Research (WEAR) Lab at the NASA Johnson Space Center utilizes a collaborative approach between engineering and human factors to investigate the use of wearables for spaceflight. Zero and partial gravity environments present unique challenges to wearables that require collaborative, user-centered, and iterative approaches to the problems. Examples of the WEAR Lab's recent wearable projects for spaceflight will be discussed.

Arc-Sprayed Fe-Based Coatings from Cored Wires for Wear and Corrosion Protection in Power Engineering

Directory of Open Access Journals (Sweden)

Korobov Yury

2018-02-01

Full Text Available High wear and corrosion of parts lead to an increase in operating costs at thermal power plants. The present paper shows a possible solution to this problem through the arc spraying of protective coatings. Cored wires of the base alloying system Fe-Cr-C were used as a feedstock. Rise of wear- and heat-resistance of the coatings was achieved by additional alloying with Al, B, Ti, and Y. The wear and heat resistance of the coatings were tested via a two-body wear test accompanied by microhardness measurement and the gravimetric method, respectively. A high-temperature corrosion test was performed at 550 °C under KCl salt deposition. The porosity and adhesion strengths of the coatings were also evaluated. The microstructure was investigated with a scanning electron microscope (SEM unit equipped with an energy dispersive X-ray (EDX microanalyzer, and the phase composition was assessed by X-ray diffractometry. The test results showed the positive influence of additional alloying with Y on the coating properties. A comparison with commercial boiler materials showed that the coatings have the same level of heat resistance as austenite steels and are an order of magnitude higher than that of pearlite and martensite-ferrite steels. The coatings can be applied to wear- and heat-resistant applications at 20–700 °C.

A model for predicting wear rates in tooth enamel.

Science.gov (United States)

Borrero-Lopez, Oscar; Pajares, Antonia; Constantino, Paul J; Lawn, Brian R

2014-09-01

It is hypothesized that wear of enamel is sensitive to the presence of sharp particulates in oral fluids and masticated foods. To this end, a generic model for predicting wear rates in brittle materials is developed, with specific application to tooth enamel. Wear is assumed to result from an accumulation of elastic-plastic micro-asperity events. Integration over all such events leads to a wear rate relation analogous to Archard׳s law, but with allowance for variation in asperity angle and compliance. The coefficient K in this relation quantifies the wear severity, with an arbitrary distinction between 'mild' wear (low K) and 'severe' wear (high K). Data from the literature and in-house wear-test experiments on enamel specimens in lubricant media (water, oil) with and without sharp third-body particulates (silica, diamond) are used to validate the model. Measured wear rates can vary over several orders of magnitude, depending on contact asperity conditions, accounting for the occurrence of severe enamel removal in some human patients (bruxing). Expressions for the depth removal rate and number of cycles to wear down occlusal enamel in the low-crowned tooth forms of some mammals are derived, with tooth size and enamel thickness as key variables. The role of 'hard' versus 'soft' food diets in determining evolutionary paths in different hominin species is briefly considered. A feature of the model is that it does not require recourse to specific material removal mechanisms, although processes involving microplastic extrusion and microcrack coalescence are indicated. Published by Elsevier Ltd.

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.

Correlation between the wear behaviour and the mechanical properties of several surface treatments

International Nuclear Information System (INIS)

Lelait, L.; Lina, A.; Rezakhanlou, R.; Duysen, J.C. van; Stebut, J. von

1993-01-01

Surface mechanical strength of chromium base (electrolytic and plasma sprayed) coatings is studied for friction and wear applications in nuclear environment. Indentation, scratch, and wear testing results are compared. In particular intrinsic coating brittleness is investigated as a mechanism responsible for impact wear. Electrolytic, hard chromium plate has a wear resistance well below that of the spray coated specimens studied. Acoustic emission level and brittle damage features are shown to be correlated. (orig.)

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

Energy Technology Data Exchange (ETDEWEB)

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

2009-05-21

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

Experimental fretting-wear studies of steam generator materials

International Nuclear Information System (INIS)

Fisher, N.J.; Chow, A.B.; Weckwerth, M.K.

1994-01-01

Flow-induced vibration of steam generator tubes results in fretting-wear damage due to impacting and rubbing of the tubes against their supports. This damage can be predicted by computing tube response to flow-induced excitation forces using analytical techniques, and then relating this response to resultant wear damage using experimentally-derived wear coefficients. Fretting-wear of steam generator materials has been studied experimentally at Chalk River Laboratories for two decades. Tests are conducted in machines that simulate steam generator environmental conditions and tube-to-support dynamic interactions. Different tube and support materials, tube-to-support clearances and tube support geometries have been studied. As well, the effect of environmental conditions, such as temperature, oxygen content, pH and chemistry control additive, have been investigated. Early studies showed that damage was related to contact force as long as other parameters, such as geometry and motion were held constant. Later studies have shown that damage is related to a parameter called work-rate, which combines both contact force and sliding distance. Results of short- and long-term fretting-wear tests for CANDU steam generator materials at realistic environmental conditions are presented. These results demonstrate that work-rate is appropriate correlating parameter for impact-sliding interaction

Development of wear-resistant coatings for cobalt-base alloys

International Nuclear Information System (INIS)

Cockeram, B.V.

1999-01-01

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

Wear of liquid nitrogen-cooled 440C bearing steels in an oxygen environment

Science.gov (United States)

Chaudhuri, Dilip K.; Verma, Ravi

1988-01-01

This paper presents up-to-date findings of the research being conducted to understand the mechanism of sliding wear in unlubricated 440C bearing steels under oxidative conditions. A sliding wear test rig has been designed and built with a cylinder-on-flat geometry. The equipment is capable of testing specimens under high axial loads and sliding speeds in a simulated LOX environment. Samples of 440C steel, quenched and tempered to a hardness of Rc 56, were tested under a load of 890 N and a sliding speed of 2.05 m/sec for total sliding distances of up to 5.54 km. Flash temperatures during these tests were measured with an IR camera and a fast digital recorder. Microstructural and microanalytical data from the worn surfaces and the debris particles are analyzed extensively, along with wear rates, flash temperatures, surface profiles, hardnesses, and residual stresses, in the context of oxidation and wear theories.

Dynamic SEM wear studies of tungsten carbide cermets. [friction and wear experiments

Science.gov (United States)

Brainard, W. A.; Buckley, D. H.

1975-01-01

Dynamic friction and wear experiments were conducted in a scanning electron microscope. The wear behavior of pure tungsten carbide and composite with 6 and 15 weight percent cobalt binder was examined, and etching of the binder was done to selectively determine the role of the binder in the wear process. Dynamic experiments were conducted as the tungsten carbide (WC) and bonded WC cermet surfaces were transversed by a 50 micron radiused diamond stylus. These studies show that the predominant wear process in WC is fracture initiated by plastic deformation, and the wear of the etched cermets is similar to pure WC. The presence of the cobalt binder reduces both friction and wear. The cementing action of the cobalt reduces granular separation, and promotes a dense polished layer because of its low shear strength film-forming properties. The wear debris generated from unetched surface is approximately the same composition as the bulk.

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

. The mean wear depth was measured using the traditionally employed 2D and compared with the 3D profilometric (digital) techniques. Data were submitted to analyses of variance, Tukey's post hoc tests and Independent Samples Student's t-tests (where appropriate) at p...OBJECTIVE: To investigate the use of a three-dimensional (3D) digital scanning method in determining the accuracy of the wear performance parameters of resin-based composites (RBCs) determined using a two-dimensional (2D) analogue methodology following in-vitro testing in an Academisch Centrum...... for Tandheelkunde Amsterdam (ACTA) wear machine. METHODS: Specimens compatible with the compartments of the ACTA wear machine specimen wheel (n=10) were prepared from one commercial and four experimental RBCs. The RBC specimens were rotated against an antagonist wheel in a food-like slurry for 220,000 wear cycles...

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...

Fretting wear of steam generator tubes: high-temperature tests on AECL rig

International Nuclear Information System (INIS)

Guerout, F.; Zbinden, M.

1993-07-01

The R and DD has undertaken the study of fretting-wear of Alloy 600 S.G. tubes which occurs by contact with migrating items. The test series was performed in Canada at AECL Research (Atomic Energy of Canada Limited) as part of an exchange program. Four types of configuration were envisaged: a tube-to-drilled hole support contact which provides reference results and three types of tube-to-support contacts which simulate the tube fretting-wear induced by a welding rod, a threaded rod and a knife-edge rod support. This programme is completed by the study of the contact between a S.G. tube and a neighbouring S.G. tube which has been broken after plugging. (authors). 1 tab., 3 refs

Effect of Heat Treatment on the Hardness and Wear of Grinding Balls

Science.gov (United States)

Aissat, Sahraoui; Sadeddine, Abdelhamid; Bradai, Mohand Amokrane; Younes, Rassim; Bilek, Ali; Benabbas, Abderrahim

2017-09-01

The effect quenching and tempering by different regimes on Rockwell hardness and wear processes of grinding balls 50 and 70 mm in diameter made of two melts of chromium-molybdenum cast iron is studied. The heating temperature for quenching is 850, 950, and 1050°C; the tempering temperature is 250, 400, and 600°C. Iron is analyzed in an electron microscope. Diffraction patterns are obtained. A model of cast iron wear is suggested and compared to the Davis model and to experimental results. An optimum heat treatment regime is proposed.

Isotopic study of the wear of sliding bearings with plastic friction surface

International Nuclear Information System (INIS)

Pandur, J.; Varkonyi, A.

1978-01-01

A new complex device has been elaborated for the investigation of the duration of bearings in the Institute of Isotopes of the Hungarian Academy of Sciences. The simultaneous determination of wear by an isotopic method the coefficient of friction by means of a Wheatstone bridge and the bearing temperature by means of a thermoresistor is described. Dynamic loading and variable revolution per minute are applied to produce a forced wear of the bearings. The isotopically labelled wear products are removed by oil and the collected sample is measured by a scintillation detector. Wear of a steel axle in plastic housing and plastic coated axle in cast iron housing was determined. (V.N.)

Wear-Induced Changes in FSW Tool Pin Profile: Effect of Process Parameters

Science.gov (United States)

Sahlot, Pankaj; Jha, Kaushal; Dey, G. K.; Arora, Amit

2018-06-01

Friction stir welding (FSW) of high melting point metallic (HMPM) materials has limited application due to tool wear and relatively short tool life. Tool wear changes the profile of the tool pin and adversely affects weld properties. A quantitative understanding of tool wear and tool pin profile is crucial to develop the process for joining of HMPM materials. Here we present a quantitative wear study of H13 steel tool pin profile for FSW of CuCrZr alloy. The tool pin profile is analyzed at multiple traverse distances for welding with various tool rotational and traverse speeds. The results indicate that measured wear depth is small near the pin root and significantly increases towards the tip. Near the pin tip, wear depth increases with increase in tool rotational speed. However, change in wear depth near the pin root is minimal. Wear depth also increases with decrease in tool traverse speeds. Tool pin wear from the bottom results in pin length reduction, which is greater for higher tool rotational speeds, and longer traverse distances. The pin profile changes due to wear and result in root defect for long traverse distance. This quantitative understanding of tool wear would be helpful to estimate tool wear, optimize process parameters, and tool pin shape during FSW of HMPM materials.

A State of the Art Report on Wear Damage of Steam Generator Tubes

International Nuclear Information System (INIS)

Lim, Yun Soo; Kim, Joung Soo; Kim, Hong Pyo; Hwang, Seong Sik; Jung, Man Kyo

2004-10-01

The recent status on wear damage of steam generator tubes caused by flow-induced vibration was investigated, and the criteria for structural integrity evaluation of the wear-damaged tubes were reviewed. It was surveyed how the wear damage of tubes could be affected by main parameters, such as, materials properties and their combination, impact load and vibration amplitude/frequency, contact areas and diametral clearance between the tube and tube support plate, wear test duration, and test temperature. Finally, corrosive wear, which means the combined action of corrosion and wear simultaneously, was also surveyed in this report. There has been only a few works concerned on the wear damage of steam generator tubes in Korea, compared with the leading foreign research institutes. Especially, the experience related to the wear characteristics of Alloy 690, which has become a replacement material for Alloy 600 as steam generator tubes, is far from satisfactory. Systematic studies, therefore, concerned with structural integrity of tubes as well as improvement of were resistance of Alloy 690 in the PWR environment are needed

Study on influence of Surface roughness of Ni-Al2O3 nano composite coating and evaluation of wear characteristics

Science.gov (United States)

Raghavendra, C. R.; Basavarajappa, S.; Sogalad, Irappa

2018-02-01

Electrodeposition is one of the most technologically feasible and economically superior techniques for producing metallic coating. The advancement in the application of nano particles has grabbed the attention in all fields of engineering. In this present study an attempt has been made on the Ni-Al2O3nano particle composite coating on aluminium substrate by electrodeposition process. The aluminium surface requires a specific pre-treatment for better adherence of coating. In light of this a thin zinc layer is coated on the aluminium substrate by electroless process. In addition to this surface roughness is an important parameter for any coating method and material. In this work Ni-Al2O3 composite coating were successfully coated by varying the process parameters such as bath temperature, current density and particle loading. The experimentation was performed using central composite design based 20 trials of experiments. The effect of process parameters and surface roughness before and after coating is analyzed on wear rate and coating thickness. The results shown a better wear resistance of Ni-Al2O3 composite electrodeposited coating compared to Ni coating. The particle loading and interaction effect of current density with temperature has greater significant effect on wear rate. The surface roughness is significantly affected the wear behaviour and thickness of coating.

Calculation of wear (f.i. wear modulus) in the plastic cup of a hip joint prosthesis

NARCIS (Netherlands)

Ligterink, D.J.

1975-01-01

The wear equation is applied to the wear process in a hip joint prosthesis and a wear modulus is defined. The sliding distance, wear modulus, wear volume, wear area, contact angle and the maximum normal stress were calculated and the theoretical calculations applied to test results. During the wear

The effects of various reinforcements on dry sliding wear behaviour of AA 6061 nanocomposites

International Nuclear Information System (INIS)

Jeyasimman, D.; Narayanasamy, R.; Ponalagusamy, R.; Anandakrishnan, V.; Kamaraj, M.

2014-01-01

Highlights: • Wear and friction coefficient of nanocomposites were investigated. • The worn surface morphologies of nanocomposites were analysed. • The wear rate was increased with increasing load and sliding velocity. • The friction coefficient was decreased with increasing load and sliding velocity. - Abstract: The present work aims to investigate the dry sliding wear behaviour of AA 6061 nanocomposites reinforced with various nanolevel reinforcements, such as titanium carbide (TiC), gamma phase alumina (γ-Al 2 O 3 ) and hybrid (TiC + Al 2 O 3 ) nanoparticles with two weight percentages (wt.%) prepared by 30 h of mechanical alloying (MA). The tests were performed using a pin-on-disk wear tester by sliding these pin specimens at sliding speeds of 0.6, 0.9 and 1.2 m/s against an oil-hardened non-shrinking (OHNS) steel disk at room temperature. Wear tests were conducted for normal loads of 5, 7 and 10 N at different sliding speeds at room temperature. The variations of the friction coefficient and the wear rate with the sliding distances (500 m, 1000 m and 1600 m) for different normal loads and sliding velocities were plotted and investigated. To observe the wear characteristics and to investigate the wear mechanism, the morphologies of the worn surfaces were analysed using a scanning electron microscope (SEM). The formation of an oxide layer on the worn surface was examined by energy dispersive spectroscopy (EDS). The wear rate was found to increase with the load and sliding velocity for all prepared nanocomposites. Hybrid (TiC + Al 2 O 3 ) reinforced AA 6061 nanocomposites had lower wear rates and friction coefficients compared with TiC and Al 2 O 3 reinforced AA 6061 nanocomposites

Fuel rod-grid interaction wear: in-reactor tests (LWBR development program)

International Nuclear Information System (INIS)

Stackhouse, R.M.

1979-11-01

Wear of the Zircaloy cladding of LWBR irradiation test fuel rods, resulting from relative motion between rod and rod support contacts, is reported. Measured wear depths were small, 0.0 to 2.7 mils, but are important in fuel element behavior assessment because of the local loss of cladding thickness, as well as the effect on grid spring forces that laterally restrain the rods. An empirical wear analysis model, based on out-of-pile tests, is presented. The model was used to calculate the wear on the irradiation test fuel rods attributed to a combination of up-and-down motions resulting from power and pressure/temperature cycling of the test reactor, flow-induced vibrations, and assembly handling scratches. The calculated depths are generally deeper than the measured depths

Fatigue and wear of metalloid-ion-implanted metals

International Nuclear Information System (INIS)

Hohmuth, K.; Richter, E.; Rauschenbach, B.; Blochwitz, C.

1985-01-01

The effect of metalloid ion implantation on the fatigue behaviour and wear of nickel and two steels has been investigated. These metals were implanted with boron, carbon and nitrogen ions at energies from 30 to 60 keV and with doses from 1 X 10 16 to 1 X 10 18 ions cm -2 at room temperature. The mechanical behaviour of fatigued nickel was studied in push-pull tests at room temperature. Wear measurements were made using a pin-and-disc technique. The surface structure, dislocation arrangement and modification of the implantation profile resulting from mechanical tests on metals which had been implanted with metalloid ions were examined using high voltage electron microscopy, transmission high energy electron diffraction, scanning electron microscopy and Auger electron spectroscopy. It is reported that nitrogen and boron ion implantation improves the fatigue lifetime, changes the number and density of the slip bands and modifies the dislocation arrangements in nickel. The cyclic deformation leads to recrystallization of the boron-ion-induced amorphous structure of nickel and to diffusion of the boron and nitrogen in the direction of the surface. The wear behaviour of steels was improved by implantation of mass-separated ions and by implantation of ions without mass separation. (Auth.)

PWR control rods wear by vibrations induced by coolant fluid

International Nuclear Information System (INIS)

Reynier, R.

1997-01-01

Flow induced vibrations in pressurised water reactors generate the wear of control rods against their guidance systems. Alternate sliding (at 320 deg. C in water) and impact-sliding tests (at room temperature in air) were carried out on 304 L austenitic stainless steel control rods' claddings. Microstructural analysis were made on the wear scars of the tube specimen using Scanning ELectron Microscopy, microhardness measurements and X-ray diffractometry. The alternate sliding leads to an important mass loss, a strong plastic deformation due to the strain hardening of the surface layers and generates strong compressive residual stresses. These results are specific to a severe wear case. Therefore, the impact-sliding mode induces martensitic phase, a cracked oxide layer and a compressive residual stresses weaker than those created in the alternate sliding case. This type of motion leads to a milder wear of the control rods

FIBROUS MONOLITH WEAR RESISTANT COMPONENTS FOR THE MINING INDUSTRY

Energy Technology Data Exchange (ETDEWEB)

Mike L. Fulcher; Kenneth L. Knittel

2004-06-08

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. Field testing provided by partners Superior Rock Bit and Brady Mining and Construction provided insight into the performance of the fabricated materials under actual operational conditions. Additional field testing of cross-cutting technology, the extrusion of hot metals, at Extruded Metals showed the potential for additional market development.

Hydrogen ion induced ultralow wear of PEEK under extreme load

Science.gov (United States)

Yan, Shuai; Wang, Anying; Fei, Jixiong; Wang, Zhenyang; Zhang, Xiaofeng; Lin, Bin

2018-03-01

As a high-performance engineering polymer, poly(ether ether ketone) (PEEK) is a perfect candidate material for applications under extreme working conditions. However, its high wear rate greatly shortens its service life. In this study, ultralow friction and wear between PEEK and silicon nitride (Si3N4) under extreme-load conditions (with a mean contact pressure above 100 MPa) are found in acid lubricating solutions. Both friction and wear decrease sharply with decreasing pH. At pH = 1, the friction coefficient decreases by an order of magnitude and the wear rate of the PEEK decreases by two orders of magnitude compared to the results with water lubrication. These reductions in friction and wear occur for different speed, load, and surface roughness conditions. The underlying mechanism can be attributed to the formation of hydrogen-ion-induced electrical double layers on the surfaces of PEEK and Si3N4. The combined effect of the resulting repulsive force, electro-viscosity, and low shear strength of the water layer dramatically reduces both friction and wear.

Multi-objective optimization of swash plate forging process parameters for the die wear/service life improvement

Science.gov (United States)

Hu, X. F.; Wang, L. G.; Wu, H.; Liu, S. S.

2017-12-01

For the forging process of the swash plate, the author designed a kind of multi-index orthogonal experiment. Based on the Archard wear model, the influences of billet temperature, die temperature, forming speed, top die hardness and friction coefficient on forming load and die wear were numerically simulated by DEFORM software. Through the analysis of experimental results, the best forging process parameters were optimized and determined, which could effectively reduce the die wear and prolong the die service life. It is significant to increase the practical production of enterprise, especially to reduce the production cost and to promote enterprise profit.

New reciprocating sliding wear testing apparatus for high temperature gaseous environments

Energy Technology Data Exchange (ETDEWEB)

Smith, A.F.; Radford, T.J.; Mawson, D.; Kaye, P.

1988-09-01

A new reciprocating wear testing rig is described that has been designed, built and commissioned at the Berkeley Nuclear Laboratories, United Kingdom. The objectives of this work are to improve upon the range of parameters offered by the existing rigs and to provide additional facilities for data acquisition and analysis.

Wear rate optimization of Al/SiCnp/e-glass fibre hybrid metal matrix composites using Taguchi method and genetic algorithm and development of wear model using artificial neural networks

Science.gov (United States)

Bongale, Arunkumar M.; Kumar, Satish; Sachit, T. S.; Jadhav, Priya

2018-03-01

Studies on wear properties of Aluminium based hybrid nano composite materials, processed through powder metallurgy technique, are reported in the present study. Silicon Carbide nano particles and E-glass fibre are reinforced in pure aluminium matrix to fabricate hybrid nano composite material samples. Pin-on-Disc wear testing equipment is used to evaluate dry sliding wear properties of the composite samples. The tests were conducted following the Taguchi’s Design of Experiments method. Signal-to-Noise ratio analysis and Analysis of Variance are carried out on the test data to find out the influence of test parameters on the wear rate. Scanning Electron Microscopic analysis and Energy Dispersive x-ray analysis are conducted on the worn surfaces to find out the wear mechanisms responsible for wear of the composites. Multiple linear regression analysis and Genetic Algorithm techniques are employed for optimization of wear test parameters to yield minimum wear of the composite samples. Finally, a wear model is built by the application of Artificial Neural Networks to predict the wear rate of the composite material, under different testing conditions. The predicted values of wear rate are found to be very close to the experimental values with a deviation in the range of 0.15% to 8.09%.

Ultrananocrystalline diamond film as a wear resistant and protective coating for mechanical seal applications

International Nuclear Information System (INIS)

Sumant, A.V.; Krauss, A.R.; Gruen, D.M.; Auciello, O.; Erdemir, A.; Williams, M.; Artiles, A.F.; Adams, W.

2005-01-01

Mechanical shaft seals used in pumps are critically important to the safe operation of the paper, pulp, and chemical process industry, as well as petroleum and nuclear power plants. Specifically, these seals prevent the leakage of toxic gases and hazardous chemicals to the environment and final products from the rotating equipment used in manufacturing processes. Diamond coatings have the potential to provide negligible wear, ultralow friction, and high corrosion resistance for the sliding surfaces of mechanical seals, because diamond exhibits outstanding tribological, physical, and chemical properties. However, diamond coatings produced by conventional chemical vapor deposition (CVD) exhibit high surface roughness (R a ≥ 1 μm), which results in high wear of the seal counterface, leading to premature seal failure. To avoid this problem, we have developed an ultrananocrystalline diamond (UNCD) film formed by a unique CH 4 /Ar microwave plasma CVD method. This method yields extremely smooth diamond coatings with surface roughness R a = 20-30 nm and an average grain size of 2-5 nm. We report the results of a systematic test program involving uncoated and UNCD-coated SiC shaft seals. Results confirmed that the UNCD-coated seals exhibited neither measurable wear nor any leakage during long-duration tests that took 21 days to complete. In addition, the UNCD coatings reduced the frictional torque for seal rotation by five to six times compared with the uncoated seals. This work promises to lead to rotating shaft seals with much improved service life, reduced maintenance cost, reduced leakage of environmentally hazardous materials, and increased energy savings. This technology may also have many other tribological applications involving rolling or sliding contacts.

Accuracy and precision of estimating age of gray wolves by tooth wear

Science.gov (United States)

Gipson, P.S.; Ballard, W.B.; Nowak, R.M.; Mech, L.D.

2000-01-01

We evaluated the accuracy and precision of tooth wear for aging gray wolves (Canis lupus) from Alaska, Minnesota, and Ontario based on 47 known-age or known-minimum-age skulls. Estimates of age using tooth wear and a commercial cementum annuli-aging service were useful for wolves up to 14 years old. The precision of estimates from cementum annuli was greater than estimates from tooth wear, but tooth wear estimates are more applicable in the field. We tended to overestimate age by 1-2 years and occasionally by 3 or 4 years. The commercial service aged young wolves with cementum annuli to within ?? 1 year of actual age, but under estimated ages of wolves ???9 years old by 1-3 years. No differences were detected in tooth wear patterns for wild wolves from Alaska, Minnesota, and Ontario, nor between captive and wild wolves. Tooth wear was not appropriate for aging wolves with an underbite that prevented normal wear or severely broken and missing teeth.

Porosity and wear resistance of flame sprayed tungsten carbide coatings

Science.gov (United States)

Winarto, Winarto; Sofyan, Nofrijon; Rooscote, Didi

2017-06-01

Thermal-sprayed coatings offer practical and economical solutions for corrosion and wear protection of components or tools. To improve the coating properties, heat treatment such as preheat is applied. The selection of coating and substrate materials is a key factor in improving the quality of the coating morphology after the heat treatment. This paper presents the experimental results regarding the effect of preheat temperatures, i.e. 200°C, 300°C and 400°C, on porosity and wear resistance of tungsten carbide (WC) coating sprayed by flame thermal coating. The powders and coatings morphology were analyzed by a Field Emission Scanning Electron Microscope equipped with Energy Dispersive Spectrometry (FE-SEM/EDS), whereas the phase identification was performed by X-Ray diffraction technique (XRD). In order to evaluate the quality of the flame spray obtained coatings, the porosity, micro-hardness and wear rate of the specimens was determined. The results showed that WC coating gives a higher surface hardness from 1391 HVN up to 1541 HVN compared to that of the non-coating. Moreover, the wear rate increased from 0.072 mm3/min. to 0.082 mm3/min. when preheat temperature was increased. Preheat on H13 steel substrate can reduce the percentage of porosity level from 10.24 % to 3.94% on the thermal spray coatings.

Low-temperature growth of low friction wear-resistant amorphous carbon nitride thin films by mid-frequency, high power impulse, and direct current magnetron sputtering

International Nuclear Information System (INIS)

Bakoglidis, Konstantinos D.; Schmidt, Susann; Garbrecht, Magnus; Ivanov, Ivan G.; Jensen, Jens; Greczynski, Grzegorz; Hultman, Lars

2015-01-01

The potential of different magnetron sputtering techniques for the synthesis of low friction and wear resistant amorphous carbon nitride (a-CN x ) thin films onto temperature-sensitive AISI52100 bearing steel, but also Si(001) substrates was studied. Hence, a substrate temperature of 150 °C was chosen for the film synthesis. The a-CN x films were deposited using mid-frequency magnetron sputtering (MFMS) with an MF bias voltage, high power impulse magnetron sputtering (HiPIMS) with a synchronized HiPIMS bias voltage, and direct current magnetron sputtering (DCMS) with a DC bias voltage. The films were deposited using a N 2 /Ar flow ratio of 0.16 at the total pressure of 400 mPa. The negative bias voltage, V s , was varied from 20 to 120 V in each of the three deposition modes. The microstructure of the films was characterized by high-resolution transmission electron microscopy and selected area electron diffraction, while the film morphology was investigated by scanning electron microscopy. All films possessed an amorphous microstructure, while the film morphology changed with the bias voltage. Layers grown applying the lowest substrate bias of 20 V exhibited pronounced intercolumnar porosity, independent of the sputter technique. Voids closed and dense films are formed at V s  ≥ 60 V, V s  ≥ 100 V, and V s  = 120 V for MFMS, DCMS, and HiPIMS, respectively. X-ray photoelectron spectroscopy revealed that the nitrogen-to-carbon ratio, N/C, of the films ranged between 0.2 and 0.24. Elastic recoil detection analysis showed that Ar content varied between 0 and 0.8 at. % and increased as a function of V s for all deposition techniques. All films exhibited compressive residual stress, σ, which depends on the growth method; HiPIMS produces the least stressed films with values ranging between −0.4 and −1.2 GPa for all V s , while CN x films deposited by MFMS showed residual stresses up to −4.2 GPa. Nanoindentation showed a significant

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.

Analysis of mechanism of carbide tool wear and control by wear process

Directory of Open Access Journals (Sweden)

Pham Hoang Trung

2017-01-01

Full Text Available The analysis of physic-mechanical and thermal physic properties of hard alloys depending on their chemical composition is conducted. The correlation of cutting properties and regularities of carbide tool wear with cutting conditions and thermal physic properties of tool material are disclosed. Significant influence on the tool wear of not only mechanical, but, in the first place, thermal physic properties of tool and structural materials is established by the researches of Russian scientists, because in the range of industrial used cutting speeds the cause of tool wear are diffusion processes. The directions of intensity decreasing of tool wear by determining rational processing conditions, the choice of tool materials and wear-resistant coating on tool surface are defined.

Influence of nitrogen ion implantation on wear studied by a new laboratory wear test

Energy Technology Data Exchange (ETDEWEB)

Szilagyi, E.; Paszti, F.; Vertessy, Z. (Central Research Inst. for Physics, Hungarian Academy of Sciences, Budapest (Hungary))

1991-05-01

A new laboratory wear test is developed in which the wear trace is measured by Rutherford backscattering spectrometry. The advantage of the new test is that the wear rate is directly determinable. The new test setup has been used to study the effects of nitrogen implantation on the wear processes on 115CrV3 steel. The wear rate decreases by a factor of 2 at 4x10{sup 17} N{sup +}/cm{sup 2} implanted dose. (orig.).

Wear behavior of A356/M{sub 7}C{sub 3} and A356/SiC particulate metal matrix composites

Energy Technology Data Exchange (ETDEWEB)

Turhan, H. [Univ. of Firat, Dept. of Metallurgy, Elazig (Turkey); Yilmaz, O. [Univ. of Firat, Dept. of Metallurgical Engineering, Elazig (Turkey)

2002-06-01

The stability of M{sub 7}C{sub 3} carbides as reinforcement for A356 materials for tribological applications has been investigated. For this purpose, A356/M{sub 7}C{sub 3}, A356/SiC and A356/M{sub 7}C{sub 3}/SiC composites were prepared by powder metallurgy and tested at room temperature against SAE 4620 steel ring and AISI 304 stainless steel counterfaces under loads of 10 - 150 N. For comparison, also unreinforced A356 specimens were processed and tested under the same conditions. The tribological behavior was evaluated by microstructural examination of the wear-effected zones and by weight loss measurements of the specimens and counterfaces. The wear behavior of A356/M{sub 7}C{sub 3} composite gave an excellent result as function of the applied load because the M{sub 7}C{sub 3} particles act as load-bearing elements due to their excellent bonding to the Al matrix, and their interfaces withtood the wear stresses even at the highest applied load. Moreover, the M{sub 7}C{sub 3} particles limited the incorporation of wear debris into the Al matrix and reduced the wear damage occasioned to the steel counterfaces compared to that of A356 Al alloy. (orig.)

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.

A study on mechanism of wear on body seat in nozzle of diesel fuel injector

Energy Technology Data Exchange (ETDEWEB)

Jeonggee, Son; Yamashita, Toru; Sato, Susumu; Kosaka, Hidenori; Masuko, Masabumi [Tokyo Institute of Technology (Japan)

2013-06-01

Wear of nozzle's body seat of diesel fuel injector, which is caused by the collision of needle on the body seat in a nozzle, affects fuel spray behaviors and injection characteristics. Recently, to reduce the wear of body seat, DLC nozzles are widely used. The DLC on the needle which is called diamond-like carbon has a certain effect in reducing wear of body seat. However, disallowable wear is reported at limited engine operating conditions. Moreover, the wear mechanism of body seat with DLC coated needle has not been made clear yet. In this study, the influence of temperature of the body seat and fuel property on the wear of DLC nozzle was investigated with a newly developed wear testing device which was constructed based on common-rail injection system. Worn surfaces of body seat were observed by FE-SEM, laser scanning microscope and EPMA. The obtained results from the measurements show that DLC nozzle has much less wear amount than non-DLC nozzle on the body seat and the corrosive wear effect is suppressed with DLC nozzle. (orig.)

The friction and wear of γ-irradiated polytetrafluoroethylene

International Nuclear Information System (INIS)

Briscoe, B.J.; Ni, Z.

1984-01-01

The exposure of polytetrafluoroethylene (PTFE) to γ radiation significantly reduces the molecular weight but below the gross softening temperature suppresses the overall molecular domain mobility. The shear modulus and creep resistance increase but the toughness is reduced. Data are presented to substantiate these trends and to interpret their influence on the friction and wear of γ-damaged PTFE. The sliding friction on smooth rigid counterfaces increases but the wear in this configuration is decreased. The rate of abrasion on rough rigid counterfaces is increased. There is also an improvement in the ultimate load-bearing capacity. All the changes produced are a function of the exposure but most of the effects are fully manifested by 20 Mrad. The general conclusion is that the extent of the molecular mobility or migration induced by mechanical stresses, imposed in both the interface and the bulk of the polymer, has a critical effect on the friction and wear processes. (Auth.)

Properties of arc-sprayed coatings from Fe-based cored wires for high-temperature applications

Science.gov (United States)

Korobov, Yu. S.; Nevezhin, S. V.; Filiрpov, M. A.; Makarov, A. V.; Malygina, I. Yu.; Fantozzi, D.; Milanti, A.; Koivuluoto, H.; Vuoristo, P.

2017-12-01

Equipment of a thermal power plant is subjected to high temperature oxidation and wear. This raises operating costs through frequent repair of worn parts and high metal consumption. The paper proposes a possible solution to this problem through arc spraying of protective coatings. Cored wires of the Fe-Cr-C basic alloying system are used as a feedstock. Additional alloying by Al, B, Si, Ti and Y allows one to create wear- and heat-resistant coatings, which are an attractive substitute of more expensive Co- and Ni-based materials.

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.

Effects of potassium titanate fiber on the wear of automotive brake linings

Science.gov (United States)

Halberstadt, M. L.; Mansfield, J. A.; Rhee, S. K.

1977-01-01

Asbestos reinforcing fiber in an automotive friction material was replaced by an experimental ingredient having better thermal stability, and the effects on wear and friction were studied. A friction materials test machine (SAE J661a) was used to determine friction and wear, under constant energy output conditions, as a function of temperature between 121 and 343 C (250 and 650 F). When potassium titanate fiber replaced one half of the asbestos in a standard commercial lining, with a 40 percent upward adjustment of phenolic resin content, wear above 204 C (400 F) was improved by 40% and friction by 30%. Tests on a full-scale inertial dynamometer supported the findings of the sample dynamometer tests. It was demonstrated that the potassium titanate fiber contributes directly to the improvement in wear and friction.

The validity of compliance monitors to assess wearing time of thoracic-lumbar-sacral orthoses in children with spinal cord injury.

Science.gov (United States)

Hunter, Louis N; Sison-Williamson, Mitell; Mendoza, Melissa M; McDonald, Craig M; Molitor, Fred; Mulcahey, M J; Betz, Randal R; Vogel, Lawrence C; Bagley, Anita

2008-06-15

Prospective multicenter observation. To determine the validity of 3 commercially available at recording thoracic-lumbar-sacral orthosis (TLSO) wearing time of children with spinal cord injury (SCI) and to assess each monitor's function during daily activities. A major limitation to studies assessing the effectiveness of spinal prophylactic bracing is the patient's compliance with the prescribed wearing time. Although some studies have begun to use objective compliance monitors, there is little documentation of the validity of the monitors during activities of daily life and no comparisons of available monitors. Fifteen children with SCI who wore a TLSO for paralytic scoliosis were observed for 4 days during their rehabilitation stay. Three compliance monitors (2 temperature and 1 pressure sensitive) were mounted onto each TLSO. Time of brace wear from the monitors was compared with the wear time per day recorded in diaries. Observed versus monitored duration of brace wear found the HOBO (temperature sensitive) to be the most valid compliance monitor. The HOBO had the lowest average of difference and variance of difference scores. The correlation between the recorded daily entries and monitored brace wear time was also highest for the HOBO in analysis of dependent and independent scores. Bland-Altman plots showed that the pressure sensitive monitor underestimated wear time whereas the temperature monitors overestimated wear time. Compliance to prescribed wearing schedule has been a barrier to studying TLSO efficacy. All 3 monitors were found to measure TLSO compliance, but the 2 temperature monitors were more in agreement with the daily diaries. Based on its functional advantages compared with the HOBO, the StowAway TidbiT will be used to further investigate the long-term compliance of TLSO bracing in children with SCI.

An analysis of the physiologic parameters of intraoral wear: a review

International Nuclear Information System (INIS)

Lawson, Nathaniel C; Cakir, Deniz; Burgess, John O; Janyavula, Sridhar

2013-01-01

This paper reviews the conditions of in vivo mastication and describes a novel method of measuring in vitro wear. Methods: parameters of intraoral wear are reviewed in this analysis, including chewing force, tooth sliding distance, food abrasivity, saliva lubrication, and antagonist properties. Results: clinical measurement of mastication forces indicates a range of normal forces between 20 and 140 N for a single molar. During the sliding phase of mastication, horizontal movement has been measured between 0.9 and 2.86 mm. In vivo wear occurs by three-body abrasion when food particles are interposed between teeth and by two-body abrasion after food clearance. Analysis of food particles used in wear testing reveals that food particles are softer than enamel and large enough to separate enamel and restoration surfaces and act as a solid lubricant. In two-body wear, saliva acts as a boundary lubricant with a viscosity of 3 cP. Enamel is the most relevant antagonist material for wear testing. The shape of a palatal cusp has been estimated as a 0.6 mm diameter ball and the hardest region of a tooth is its enamel surface. pH values and temperatures have been shown to range between 2–7 and 5–55 °C in intraoral fluids, respectively. These intraoral parameters have been used to modify the Alabama wear testing method. (paper)

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

Effect of thermal treatments on the wear behaviour of duplex stainless steels

International Nuclear Information System (INIS)

Fargas, G; Mestra, A; Anglada, M; Mateo, A

2009-01-01

Duplex stainless steel (DSS) is a family of steels characterized by two-phase microstructure with similar percentages of ferrite (α) and austenite (γ).Their attractive combination of mechanical properties and corrosion resistance has increased its use in last decades in the marine and petrochemical industries. Nevertheless, an inappropriate heat treatment can induce the precipitation of secondary phases which affect directly their mechanical properties and corrosion resistance. There are few works dealing with the influence of heat treatments on wear behaviour of these steels in the literature. For instances, this paper aims to determine wear kinetic and sliding wear volume developed as a function of heat treatment conditions. Therefore, the samples were heat treated from 850 deg. C to 975 deg.C before sliding wear tests. These wear tests were carried out using ball on disk technique at constant sliding velocity and different sliding distances. Two methodologies were used to calculate the wear volume: weight loss and area measurement using a simplified contact model. Microstructural observations showed the presence of sigma phase for all studied conditions. The formation kinetics of this phase is faster at 875 deg. C and decrease at higher temperatures. Results related to wear showed that the hardness introduced due to the presence of sigma phase plays an important role on wear behaviour for this steel. It was observed also that wear rates decreased when increasing the percentage of sigma phase on the microstructure.

Friction and wear behavior of Inconel 625 with Ni3Ti, TiN, TiC-CVD coatings in an HTGR environment

International Nuclear Information System (INIS)

Sarosiek, A.M.; Li, C.C.

1984-04-01

The following conclusions apply to Inconel 625 with Ni 3 Ti, TiN, TiC-CVD coatings, tested in an HTGR environment in a temperature range between 500 and 900 0 C at a contact pressure of 3.45 MPa. The average wear rate is very small varying between 0.0 and 1.7 x 10 -4 g/m. The wear rate shows little dependence on temperature and sliding velocity, increasing slightly as the temperature increases or as the sliding velocity decreases. Damage experienced by wear areas is minimal. Stick-slip friction was observed at low sliding velocity, however the friction coefficient is low (maximum 0.63) with an average value of about 0.44. The friction coefficient shows little dependence on temperature and sliding velocity, increasing slightly as the temperature increases, or as the sliding velocity decreases. Ni 3 Ti, TiN, TiC-CVD coatings, are considered effective in minimizing friction and wear damage of Inconel 625 in an HTGR environment

Fretting wear characteristic tests of X2-GEN midgrid for SMART under a FIV rod trace

Energy Technology Data Exchange (ETDEWEB)

Lee, Young Ho; Lee, Kang Hee; Kim, Jae Yong; Kim, Hyung Kyu [KAERI, Daejeon (Korea, Republic of)

2011-12-15

The KEPCO Nuclear Fuel Co. requested the fretting wear characteristic tests of a X2-GEN midgrid under a FIV rod trace at room temperature air. The following results were obtained for the fretting wear test. {center_dot} Fretting wear tests under a FIV rod trace Based on the result of the fretting wear tests of the X2-GEN and 17ACE7 1x1 mid-grid under a FIV rod trace, X2-GEN mid-grid showed a slightly severe wear volume rather than 17ACE7 spring. But, maximum wear depth shows an opposite behavior. This is due to spring shape effect. The fretting wear mechanisms at each mid-grid were influenced by each spring shape, that are depended on the different impacting behavior under a FIV rod motion. Up to 5x105 cycles, wear characteristics of each mid-grid shows a relatively similar wear rate. Consequently, it is necessary to further study for examining exact fretting wear behavior under a FIV rod tra

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.

Wear calculation possibility of slide-friction pair "shaft-plain bearing" for four-stroke engines

Science.gov (United States)

Springis, Guntis; Rudzitis, Janis; Avisane, Anita; Kumermanis, Maris

2013-12-01

The issues of the service life and its prediction for main four stroke engine parts such as shaft-plain bearing have always been of particular importance. The article determines the most suitable mathematical calculation model allowing considering the set of parameters needed for the slide-friction pair's calculation, thus achieving a result as precise as possible. Since the wear process is variable and many-sided it is influenced by very many different parameters, for example, the surface geometry (roughness, waviness, form deviation, etc.), the physical and mechanical conditions of the upper layer, component material, wear regime, wear temperature, etc. The offered wear calculation model taking into consideration as much as possible wear affecting parameters is based on the fatigue theory regularities of the friction surface's destroying, using the approach of probability theory.

Structurally Integrated Coatings for Wear and Corrosion

Energy Technology Data Exchange (ETDEWEB)

Beardsley, M. Brad; Sebright, Jason L.

2008-11-18

Wear and corrosion of structures cuts across industries and continues to challenge materials scientists and engineers to develop cost effective solutions. Industries typically seek mature technologies that can be implemented for production with rapid or minimal development and have little appetite for the longer-term materials research and development required to solve complex problems. The collaborative work performed in this project addressed the complexity of this problem in a multi-year program that industries would be reluctant to undertake without government partnership. This effort built upon the prior development of Advanced Abrasion Resistant Materials conduct by Caterpillar Inc. under DOE Cooperative Agreement No. DE-FC26-01NT41054. In this referenced work, coatings were developed that exhibited significant wear life improvements over standard carburized heat treated steel in abrasive wear applications. The technology used in this referenced work, arc lamp fusing of thermal spray coatings, was one of the primary technical paths in this work effort. In addition to extending the capability of the coating technology to address corrosion issues, additional competitive coating technologies were evaluated to insure that the best technology was developed to meet the goals of the program. From this, plasma transferred arc (PTA) welding was selected as the second primary technology that was investigated. Specifically, this project developed improved, cost effective surfacing materials and processes for wear and corrosion resistance in both sliding and abrasive wear applications. Materials with wear and corrosion performance improvements that are 4 to 5 times greater than heat treated steels were developed. The materials developed were based on low cost material systems utilizing ferrous substrates and stainless steel type matrix with hard particulates formed from borides and carbides. Affordability was assessed against other competing hard surfacing or coating

Wear Characteristics According of Heat Treatment of Si3N4 with Different Amounts of SiO2 Nano-Colloid

International Nuclear Information System (INIS)

Ahn, Seok Hwan; Nam, Ki Woo

2014-01-01

This study sintered Si 3 N 4 with different amounts of SiO 2 nano-colloid. The surface of a mirror-polished specimen was coated with SiO 2 nano-colloid, and cracks were healed when the specimen was treated at a temperature of 1273 K for 1 h in air. Wear specimen experiments were conducted after heat treatments for 10 min at 1073, 1273, and 1573 K. The heat-treated surface that was coated with the SiO 2 nano-colloid was slightly rougher than the noncoated surface. The oxidation state of the surface according to the heat treatment temperature showed no correlation with the surface roughness. Moreover, the friction coefficient, wear loss, and bending strength were not related to the surface roughness. Si 3 N 4 exhibited an abrasive wear behavior when SKD11 was used as an opponent material. The friction coefficient was proportional to the wear loss, and the bending strength was inversely proportional to the friction coefficient and wear loss. The friction coefficient and wear loss increased with increasing amounts of the SiO 2 nanocolloid. In addition, the friction coefficient was slightly increased by increasing the heat treatment temperature

Performance Degradation Analysis of Aviation Hydraulic Piston Pump Based on Mixed Wear Theory

Directory of Open Access Journals (Sweden)

C. Zhang

2017-06-01

Full Text Available This paper focuses on the mathematical modeling of axial piston pump through dividing the failure development of friction pair into lubrication, mixed lubrication and abrasion. Directing to the wedge-shaped oil film between cylinder block and valve plate, the support force distribution under the temperature variance was obtained. Considering the rough peak of valve plate, the contact load model is built under plastic deformation and elastic deformation and the corresponding wear volume is calculated. Computing the wear and tear along the counter-clockwise, the total amount of friction and wear can be calculated. Simulation and preliminary wear particle monitoring test indicates that proposed modeling and analysis can effectively reflect the real abrasion process of hydraulic piston pump.

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.

Wear resistance and fracture mechanics of WC-Co composites

International Nuclear Information System (INIS)

Kaytbay, Saleh; El-Hadek, Medhat

2014-01-01

Manufacturing of WC-Co composites using the electroless precipitation method at different sintering temperatures of 1 100, 1 250, 1 350 and 1 500 C was successfully achieved. The chemical composition of the investigated materials was 90 wt.% WC with 10 wt.% Co, and 80 wt.% WC with 20 wt.% Co. The specific density, densification, and Vickers microhardness measurements were found to increase with increased sintering temperature for both the WC-Co compositions. The composites of tungsten carbide with 10 wt.% Co had a higher specific density and Vickers microhardness measurements than those for the composites of tungsten carbide with 20 wt.% Co. Composites with WC-10 wt.% Co had better wear resistance. The stress-strain and transverse rupture strength increased monotonically with the increase in sintering temperatures, agreeing with the material hardness and wear resistance behavior. Fractographical scanning electron microscopy analysis of the fracture surface demonstrated a rough characteristic conical shape failure in the direction of the maximum shear stress. A proposed mechanism for the formation of the conical fracture surface under compression testing is presented. (orig.)

On airborne nano/micro-sized wear particles released from low-metallic automotive brakes

International Nuclear Information System (INIS)

Kukutschova, Jana; Moravec, Pavel; Tomasek, Vladimir; Matejka, Vlastimil; Smolik, Jiri; Schwarz, Jaroslav; Seidlerova, Jana; Safarova, Klara; Filip, Peter

2011-01-01

The paper addresses the wear particles released from commercially available 'low-metallic' automotive brake pads subjected to brake dynamometer tests. Particle size distribution was measured in situ and the generated particles were collected. The collected fractions and the original bulk material were analyzed using several chemical and microscopic techniques. The experiments demonstrated that airborne wear particles with sizes between 10 nm and 20 μm were released into the air. The numbers of nanoparticles (<100 nm) were by three orders of magnitude larger when compared to the microparticles. A significant release of nanoparticles was measured when the average temperature of the rotor reached 300 deg. C, the combustion initiation temperature of organics present in brakes. In contrast to particle size distribution data, the microscopic analysis revealed the presence of nanoparticles, mostly in the form of agglomerates, in all captured fractions. The majority of elements present in the bulk material were also detected in the ultra-fine fraction of the wear particles. - Research highlights: → Wear of low-metallic friction composite produces airborne nano-sized particles. → Nano-sized particles contain carbon black and metallic compounds. → Carbon black nano-sized particles are related to resin degradation. → Number of nanoparticles higher by three orders of magnitude than microparticles. - Braking of automobiles may contribute to nano-particulate air pollution caused by friction processes associated with wear of low-metallic brake pads.

Effect of Microstructure on the Wear Behavior of Heat Treated SS-304 Stainless Steel

Directory of Open Access Journals (Sweden)

S. Kumar

2016-12-01

Full Text Available Sliding wear characteristics of some heat treated SS-304 stainless steel against EN-8 steel in dry condition have been studied in the present experimental work. Samples of SS-304 stainless steel have been heated in a muffle furnace in desired temperature and allowed to dwell for two hours. The heated specimen are then cooled in different media namely inside the furnace, open air, cutting grade oil (grade 44 and water at room temperature to obtain different grades of heat treatment. Microstructures and corresponding micro hardness of the samples have been measured along with Feritscopic studies. Wear characteristics have been studied in a multi tribo-tester (Ducom in dry sliding condition against EN-8 steel roller. Speed, load on job and duration of test run have been considered as the experimental parameters. The wear of the samples have been obtained directly from ‘Winducom 2006’ software. Mass loss of the samples before and after operation has also been considered as the measure of wear in the present study. All the samples have been slid against EN-8 steel roller with fixed experimental parameters. The data have been plotted, compared and analyzed. Effect of microstructures as well as micro hardness on the wear behavior has been studied and concluded accordingly.

Ignition of a Combustible Atmosphere by Incandescent Carbon Wear Particles

Science.gov (United States)

Buckley, Donald H.; Swikert, Max A.; Johnson, Robert L.

1960-01-01

A study was made to determine whether carbon wear particles from carbon elements in sliding contact with a metal surface were sufficiently hot to cause ignition of a combustible atmosphere. In some machinery, electric potential differences and currents may appear at the carbon-metal interface. For this reason the effect of these voltages and currents on the ability of carbon wear particles to cause ignition was evaluated. The test specimens used in the investigation were carbon vanes taken from a fuel pump and flat 21-inch-diameter 2 metal disks (440-C stainless steel) representing the pump housing. During each experiment a vane was loaded against a disk with a 0.5-pound force, and the disk was rotated to give a surface speed of 3140 feet per minute. The chamber of the apparatus that housed the vane and the disk was filled with a combustible mixture of air and propane. Various voltages and amperages were applied across the vane-disk interface. Experiments were conducted at temperatures of 75, 350, 400, and 450 F. Fires were produced by incandescent carbon wear particles obtained at conditions of electric potential as low as 106 volts and 0.3 ampere at 400 F. Ignitions were obtained only with carbon wear particles produced with an electric potential across the carbon-vane-disk interface. No ignitions were obtained with carbon wear particles produced in the absence of this potential; also, the potential difference produced no ignitions in the absence of carbon wear particles. A film supplement showing ignition by incandescent wear particles is available.

Consideration of wear rates at high velocity

Science.gov (United States)

Hale, Chad S.

The development of the research presented here is one in which high velocity relative sliding motion between two bodies in contact has been considered. Overall, the wear environment is truly three-dimensional. The attempt to characterize three-dimensional wear was not economically feasible because it must be analyzed at the micro-mechanical level to get results. Thus, an engineering approximation was carried out. This approximation was based on a metallographic study identifying the need to include viscoplasticity constitutive material models, coefficient of friction, relationships between the normal load and velocity, and the need to understand wave propagation. A sled test run at the Holloman High Speed Test Track (HHSTT) was considered for the determination of high velocity wear rates. In order to adequately characterize high velocity wear, it was necessary to formulate a numerical model that contained all of the physical events present. The experimental results of a VascoMax 300 maraging steel slipper sliding on an AISI 1080 steel rail during a January 2008 sled test mission were analyzed. During this rocket sled test, the slipper traveled 5,816 meters in 8.14 seconds and reached a maximum velocity of 1,530 m/s. This type of environment was never considered previously in terms of wear evaluation. Each of the features of the metallography were obtained through micro-mechanical experimental techniques. The byproduct of this analysis is that it is now possible to formulate a model that contains viscoplasticity, asperity collisions, temperature and frictional features. Based on the observations of the metallographic analysis, these necessary features have been included in the numerical model, which makes use of a time-dynamic program which follows the movement of a slipper during its experimental test run. The resulting velocity and pressure functions of time have been implemented in the explicit finite element code, ABAQUS. Two-dimensional, plane strain models

Effect of soot on oil properties and wear of engine components

International Nuclear Information System (INIS)

Green, D A; Lewis, R

2007-01-01

The objective of the work outlined in this paper was to increase the understanding of the wear mechanisms that occur within a soot contaminated contact zone, to help in future development of a predictive wear model to assist in the automotive engine valve train design process. The paper builds on previous work by the author, through testing of different lubricants and increased levels of soot contamination. Wear testing has been carried out using specimens operating under realistic engine conditions, using a reciprocating test-rig specifically designed for this application, where a steel disc is held in a heated bath of oil and a steel ball is attached to a reciprocating arm (replicating a sliding elephant's foot valve train contact). Detailed analysis of the test specimens has been performed using scanning electron microscopy to identify wear features relating to the proposed wear mechanisms. Analysis of worn engine components from durability engine tests has also been carried out for a comparison between specimen tests and engine testing. To assist the understanding of the wear test results obtained, the physical properties of contaminated lubricants were investigated, through viscosity, traction and friction measurements. The results have revealed how varying lubrication conditions change the wear rate of engine components and determine the wear mechanism that dominates in specific situations. Testing has also shown the positive effects of advanced engine lubricants to reduce the amount of wear produced with soot present

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

International Nuclear Information System (INIS)

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

Low-temperature growth of low friction wear-resistant amorphous carbon nitride thin films by mid-frequency, high power impulse, and direct current magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Bakoglidis, Konstantinos D., E-mail: konba@ifm.liu.se; Schmidt, Susann; Garbrecht, Magnus; Ivanov, Ivan G.; Jensen, Jens; Greczynski, Grzegorz; Hultman, Lars [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping (Sweden)

2015-09-15

The potential of different magnetron sputtering techniques for the synthesis of low friction and wear resistant amorphous carbon nitride (a-CN{sub x}) thin films onto temperature-sensitive AISI52100 bearing steel, but also Si(001) substrates was studied. Hence, a substrate temperature of 150 °C was chosen for the film synthesis. The a-CN{sub x} films were deposited using mid-frequency magnetron sputtering (MFMS) with an MF bias voltage, high power impulse magnetron sputtering (HiPIMS) with a synchronized HiPIMS bias voltage, and direct current magnetron sputtering (DCMS) with a DC bias voltage. The films were deposited using a N{sub 2}/Ar flow ratio of 0.16 at the total pressure of 400 mPa. The negative bias voltage, V{sub s}, was varied from 20 to 120 V in each of the three deposition modes. The microstructure of the films was characterized by high-resolution transmission electron microscopy and selected area electron diffraction, while the film morphology was investigated by scanning electron microscopy. All films possessed an amorphous microstructure, while the film morphology changed with the bias voltage. Layers grown applying the lowest substrate bias of 20 V exhibited pronounced intercolumnar porosity, independent of the sputter technique. Voids closed and dense films are formed at V{sub s} ≥ 60 V, V{sub s} ≥ 100 V, and V{sub s} = 120 V for MFMS, DCMS, and HiPIMS, respectively. X-ray photoelectron spectroscopy revealed that the nitrogen-to-carbon ratio, N/C, of the films ranged between 0.2 and 0.24. Elastic recoil detection analysis showed that Ar content varied between 0 and 0.8 at. % and increased as a function of V{sub s} for all deposition techniques. All films exhibited compressive residual stress, σ, which depends on the growth method; HiPIMS produces the least stressed films with values ranging between −0.4 and −1.2 GPa for all V{sub s}, while CN{sub x} films deposited by MFMS showed residual stresses up to −4.2�

Effect of Groove Surface Texture on Tribological Characteristics and Energy Consumption under High Temperature Friction.

Science.gov (United States)

Wu, Wei; Chen, Guiming; Fan, Boxuan; Liu, Jianyou

2016-01-01

Energy consumption and tribological properties could be improved by proper design of surface texture in friction. However, some literature focused on investigating their performance under high temperature. In the study, different groove surface textures were fabricated on steels by a laser machine, and their tribological behaviors were experimentally studied with the employment of the friction and wear tester under distinct high temperature and other working conditions. The friction coefficient was recorded, and wear performance were characterized by double light interference microscope, scanning electron microscope (SEM) and x-ray energy dispersive spectrometry (EDS). Then, the performances of energy consumptions were carefully estimated. Results showed that friction coefficient, wear, and energy consumption could almost all be reduced by most textures under high temperature conditions, but to a different extent which depends on the experimental conditions and texture parameters. The main improvement mechanisms were analyzed, such as the hardness change, wear debris storage, thermal stress release and friction induced temperature reduction by the textures. Finally, a scattergram of the relatively reduced ratio of the energy consumption was drawn for different surface textures under four distinctive experimental conditions to illustrate the comprehensive energy consumption improving ability of textures, which was of benefit for the application of texture design.

Microstructural and wear characteristics of cobalt free, nickel base intermetallic alloy deposited by laser cladding

International Nuclear Information System (INIS)

Awasthi, Reena; Kumar, Santosh; Viswanadham, C.S.; Srivastava, D.; Dey, G.K.; Limaye, P.K.

2011-01-01

This paper describes the microstructural and wear characteristics of Ni base intermetallic hardfacing alloy (Tribaloy-700) deposited on stainless steel-316 L substrate by laser cladding technique. Cobalt base hardfacing alloys have been most commonly used hardfacing alloys for application involving wear, corrosion and high temperature resistance. However, the high cost and scarcity of cobalt led to the development of cobalt free hardfacing alloys. Further, in the nuclear industry, the use of cobalt base alloys is limited due to the induced activity of long lived radioisotope 60 Co formed. These difficulties led to the development of various nickel and iron base alloys to replace cobalt base hardfacing alloys. In the present study Ni base intermetallic alloy, free of Cobalt was deposited on stainless steel- 316 L substrate by laser cladding technique. Traditionally, welding and thermal spraying are the most commonly employed hardfacing techniques. Laser cladding has been explored for the deposition of less diluted and fusion-bonded Nickel base clad layer on stainless steel substrate with a low heat input. The laser cladding parameters (Laser power density: 200 W/mm 2 , scanning speed: 430 mm/min, and powder feed rate: 14 gm/min) resulted in defect free clad with minimal dilution of the substrate. The microstructure of the clad layer was examined by Optical microscopy, Scanning electron microscopy, with energy dispersive spectroscopy. The phase analysis was performed by X-ray diffraction technique. The clad layer exhibited sharp substrate/clad interface in the order of planar, cellular, and dendritic from the interface upwards. Dilution of clad with Fe from substrate was very low passing from ∼ 15% at the interface (∼ 40 μm) to ∼ 6% in the clad layer. The clad layer was characterized by the presence of hexagonal closed packed (hcp, MgZn 2 type) intermetallic Laves phase dispersed in the eutectic of Laves and face centered cubic (fcc) gamma solid solution. The

A new reciprocating sliding wear testing apparatus for high temperature gaseous environments

International Nuclear Information System (INIS)

Smith, A.F.; Radford, T.J.; Mawson, D.; Kaye, P.

1988-01-01

A new reciprocating wear testing rig is described that has been designed, built and commissioned at the Berkeley Nuclear Laboratories, United Kingdom. The objectives of this work are to improve upon the range of parameters offered by the existing rigs and to provide additional facilities for data acquisition and analysis. (author)

Investigation of friction and wear characteristics of cast iron material under various conditions

Energy Technology Data Exchange (ETDEWEB)

Joo, Ji Hoon; Kim, Chang Lae; Oh, Jeong Taek; Kim, Dae Eun [Yonsei University, Seoul (Korea, Republic of); Nemati, Narguess [School of Materials and Metallurgy, University of Tehran, Tehran (Iran, Islamic Republic of)

2015-08-15

Cast iron is widely used in fields such as the transport and heavy industries. For parts where contact damage is expected to occur, it is necessary to understand the friction and wear characteristics of cast iron. In this study, we use cast iron plates as the specimens to investigate their friction and wear characteristics. We perform various experiments using a reciprocating type tribotester. We assess the frictional characteristics by analyzing the friction coefficient values that were obtained during the sliding tests. We observe the wear surfaces of cast iron and steel balls using a scanning electron microscope, confocal microscope, and 3D profiler. We investigate the friction and wear characteristics of cast iron by injecting sand and alumina particles having various sizes. Furthermore, we estimate the effect of temperature on the friction and wear characteristics. The results obtained are expected to aid in the understanding of the tribological characteristics of cast iron in industry.

Controlled wear of vitrified abrasive materials for precision grinding ...

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

2Machining Research Group, Department of Engineering, University of ... ods are applied to analyse the cutting mechanism in grinding. .... (d) Chemical reaction between abrasive and workpiece material at elevated temperatures ... most common method used for measuring wear flat area employs an optical, or an electron.

Sliding Wear and Fretting Wear of DLC-Based, Functionally Graded Nanocomposite Coatings

Science.gov (United States)

Miyoshi, K.; Pohlchuck, B.; Street, Kenneth W.; Zabinski, J. S.; Sanders, J. H.; Voevodin, A. a.; Wu, R. L. C.

1999-01-01

Improving the tribological functionality of diamondlike carbon (DLC) films--developing, good wear resistance, low friction, and high load-carrying capacity-was the aim of this investigation. Nanocomposite coatings consisting of an amorphous DLC (a-DLC) top layer and a functionally graded titanium-titanium carbon-diamondlike carbon (Ti-Ti(sub x) C(sub y)-DLC) underlayer were produced on AISI 440C stainless steel substrates by the hybrid technique of magnetron sputtering and pulsed-laser deposition. The resultant DLC films were characterized by Raman spectroscopy, scanning electron microscopy, and surface profilometry. Two types of wear experiment were conducted in this investioation: sliding friction experiments and fretting wear experiments. Unidirectional ball-on-disk sliding friction experiments were conducted to examine the wear behavior of an a-DLC/Ti-Ti(sub x) C(sub y)-DLC-coated AISI 440C stainless steel disk in sliding contact with a 6-mm-diameter AISI 440C stainless steel ball in ultrahigh vacuum, dry nitrogen, and humid air. Although the wear rates for both the coating and ball were low in all three environments, the humid air and dry nitrogen caused mild wear with burnishing, in the a-DLC top layer, and the ultrahigh vacuum caused relatively severe wear with brittle fracture in both the a-DLC top layer and the Ti-Ti(sub x) C(sub y)-DLC underlayer. For reference, amorphous hydrogenated carbon (H-DLC) films produced on a-DLC/Ti-Ti(sub x) C(sub y)-DLC nanocomposite coatings by using an ion beam were also examined in the same manner. The H-DLC films markedly reduced friction even in ultrahigh vacuum without sacrificing wear resistance. The H-DLC films behaved much like the a-DLC/Ti-Ti(sub x) C(sub y)-DLC nanocomposite coating in dry nitrogen and humid air, presenting low friction and low wear. Fretting wear experiments were conducted in humid air (approximately 50% relative humidity) at a frequency of 80 Hz and an amplitude of 75 micron on an a

Dry sliding wear behavior of epoxy composite reinforced with short palmyra fibers

International Nuclear Information System (INIS)

Biswal, Somen; Satapathy, Alok

2016-01-01

The present work explores the possibility of using palmyra fiber as a replacement for synthetic fiber in conventional polymer composites for application against wear. An attempt has been made in this work to improve the sliding wear resistance of neat epoxy by reinforcing it with short palmyra fibers (SPF). Epoxy composites with different proportions (0, 4, 8 and 12 wt. %) of SPF are fabricated by conventional hand lay-up technique. Dry sliding wear tests are performed on the composite samples using a pin-on-disc test rig as per ASTM G 99-05 standards under various operating parameters. Design of experiment approach based on Taguchi's L16 Orthogonal Arrays is used for the analysis of the wear. This parametric analysis reveals that the SPF content is the most significant factor affecting the wear process followed by the sliding velocity. The sliding wear behavior of these composites under an extensive range of test conditions is predicted by a model based on the artificial neural network (ANN). A well trained ANN has been used to predict the sliding wear response of epoxy based composites over a wide range. (paper)

Microstructure, Wear Behavior and Corrosion Resistance of WC-FeCrAl and WC-WB-Co Coatings

Directory of Open Access Journals (Sweden)

Janette Brezinová

2018-05-01

Full Text Available The paper is focused on investigating the quality of two grades of thermally sprayed coatings deposited by high-velocity oxygen fuel (HVOF technology. One grade contains WC hard particles in an environmentally progressive Ni- and Co-free FeCrAl matrix, while the second coating contains WC and WB hard particles in a cobalt matrix. The aim of the experimental work was to determine the effect of thermal cyclic loading on the coatings’ resistance to adhesive, abrasive and erosive wear. Abrasive wear was evaluated using abrasive cloth of two grit sizes, and erosive wear was evaluated by a dry-pot wear test in a pin mill at two sample angles. Adhesion wear resistance of the coatings was determined by a sliding wear test under dry friction conditions and in a 1 mol water solution of NaCl. Corrosion resistance of the coatings was evaluated using potentiodynamic polarization tests. Metallographic cross-sections were used for measurement of the microhardness and thickness and for line energy-dispersive X-ray (EDX analysis. The tests proved the excellent resistance of both coatings against adhesive, abrasive, and erosive wear, as well as the ability of the WC-WB-Co coating to withstand alternating temperatures of up to 600 °C. The “green carbide” coating (WC-FeCrAl can be recommended as an environmentally friendly replacement for Ni- and Co-containing coatings, but its operating temperature is strictly limited to 500 °C in air.

A comparative study of tribological behavior of plasma and D-gun sprayed coatings under different wear modes

International Nuclear Information System (INIS)

Sundararajan, G.; Rao, D.S.; Prasad, K.U.M.; Joshi, S.V.

1998-01-01

In recent years, thermal sprayed protective coatings have gained widespread acceptance for a variety of industrial applications. A vast majority of these applications involve the use of thermal sprayed coatings to combat wear. While plasma spraying is the most versatile variant of all the thermal spray processes, the detonation gun (D-gun) coatings have been a novelty until recently because of their proprietary nature. The present study is aimed at comparing the tribological behavior of coatings deposited using the two above techniques by focusing on some popular coating materials that are widely adopted for wear resistant applications, namely, WC-12% Co, Al 2 O 3 , and Cr 3 C 2 -NiCr. To enable a comprehensive comparison of the above indicated thermal spray techniques as well as coating materials, the deposited coatings were extensively characterized employing microstructural evaluation, microhardness measurements, and XRD analysis for phase constitution. The behavior of these coatings under different wear modes was also evaluated by determining their tribological performance when subjected to solid particle erosion tests, rubber wheel sand abrasion tests, and pin-on-disk sliding wear tests. Among all the coating materials studied, D-gun sprayed WC-12% Co, in general, yields the best performance under different modes of wear, whereas plasma sprayed Al 2 O 3 shows least wear resistance to every wear mode

A comparative wear study on Al-Li and Al-Li/SiC composite

Energy Technology Data Exchange (ETDEWEB)

Okumus, S. Cem, E-mail: cokumus@sakarya.edu.tr; Karslioglu, Ramazan, E-mail: cokumus@sakarya.edu.tr; Akbulut, Hatem, E-mail: cokumus@sakarya.edu.tr [Sakarya University Engineering Faculty, Department of Metallurgical and Materials Engineering, Esentepe Campus, 54187, Sakarya (Turkey)

2013-12-16

Aluminum-lithium based unreinforced (Al-8090) alloy and Al-8090/SiCp/17 vol.% metal matrix composite produced by extrusion after spray co-deposition. A dry ball-on disk wear test was carried out for both alloy and composite. The tests were performed against an Al{sub 2}O{sub 3} ball, 10 mm in diameter, at room temperature and in laboratory air conditions with a relative humidity of 40-60%. Sliding speed was chosen as 1.0 ms{sup −1} and normal loads of 1.0, 3.0 and 5.0 N were employed at a constant sliding distance of 1000 m. The wear damage on the specimens was evaluated via measurement of wear depth and diameter. Microstructural and wear characterization was carried out via scanning electron microscopy (SEM). The results showed that wear loss of the Al-8090/SiC composite was less than that of the Al-8090 matrix alloy. Plastic deformation observed on the wear surface of the composite and the matrix alloy, and the higher the applied load the greater the plastic deformation. Scanning electron microscopy examinations of wear tracks also reveal that delamination fracture was the dominant wear mechanism during the wear progression. Friction coefficient was maximum at the low applied load in the case of the Al-8090/SiC composite while a gradual increase was observed with applied load for the matrix alloy.

Effect of spherical Au nanoparticles on nanofriction and wear reduction in dry and liquid environments

Science.gov (United States)

Maharaj, Dave

2012-01-01

Summary Nano-object additives are used in tribological applications as well as in various applications in liquids requiring controlled manipulation and targeting. On the macroscale, nanoparticles in solids and liquids have been shown to reduce friction and wear. On the nanoscale, atomic force microscopy (AFM) studies have been performed in single- and multiple-nanoparticle contact, in dry environments, to characterize friction forces and wear. However, limited studies in submerged liquid environments have been performed and further studies are needed. In this paper, spherical Au nanoparticles were studied for their effect on friction and wear under dry conditions and submerged in water. In single-nanoparticle contact, individual nanoparticles, deposited on silicon, were manipulated with a sharp tip and the friction force was determined. Multiple-nanoparticle contact sliding experiments were performed on nanoparticle-coated silicon with a glass sphere. Wear tests were performed on the nanoscale with AFM as well as on the macroscale by using a ball-on-flat tribometer to relate friction and wear reduction on the nanoscale and macroscale. Results indicate that the addition of Au nanoparticles reduces friction and wear. PMID:23213639

Effect of spherical Au nanoparticles on nanofriction and wear reduction in dry and liquid environments

Directory of Open Access Journals (Sweden)

Dave Maharaj

2012-11-01

Full Text Available Nano-object additives are used in tribological applications as well as in various applications in liquids requiring controlled manipulation and targeting. On the macroscale, nanoparticles in solids and liquids have been shown to reduce friction and wear. On the nanoscale, atomic force microscopy (AFM studies have been performed in single- and multiple-nanoparticle contact, in dry environments, to characterize friction forces and wear. However, limited studies in submerged liquid environments have been performed and further studies are needed. In this paper, spherical Au nanoparticles were studied for their effect on friction and wear under dry conditions and submerged in water. In single-nanoparticle contact, individual nanoparticles, deposited on silicon, were manipulated with a sharp tip and the friction force was determined. Multiple-nanoparticle contact sliding experiments were performed on nanoparticle-coated silicon with a glass sphere. Wear tests were performed on the nanoscale with AFM as well as on the macroscale by using a ball-on-flat tribometer to relate friction and wear reduction on the nanoscale and macroscale. Results indicate that the addition of Au nanoparticles reduces friction and wear.

Nuclear graphite wear properties and estimation of graphite dust production in HTR-10

Energy Technology Data Exchange (ETDEWEB)

Luo, Xiaowei, E-mail: xwluo@tsinghua.edu.cn; Wang, Xiaoxin; Shi, Li; Yu, Xiaoyu; Yu, Suyuan

2017-04-15

Highlights: • Graphite dust. • The wear properties of graphite. • Pebble bed. • High Temperature Gas-cooled Reactor. • Fuel element. - Abstract: The issue of the graphite dust has been a research focus for the safety of High Temperature Gas-cooled Reactors (HTGRs), especially for the pebble bed reactors. Most of the graphite dust is produced from the wear of fuel elements during cycling of fuel elements. However, due to the complexity of the motion of the fuel elements in the pebble bed, there is no systematic method developed to predict the amount the graphite dust in a pebble bed reactor. In this paper, the study of the flow of the fuel elements in the pebble bed was carried out. Both theoretical calculation and numerical analysis by Discrete Element Method (DEM) software PFC3D were conducted to obtain the normal forces and sliding distances of the fuel elements in pebble bed. The wearing theory was then integrated with PFC3D to estimate the amount of the graphite dust in a pebble bed reactor, 10 MW High Temperature gas-cooled test Reactor (HTR-10).

Abrasive Wear Resistance of Tool Steels Evaluated by the Pin-on-Disc Testing

Science.gov (United States)

Bressan, José Divo; Schopf, Roberto Alexandre

2011-05-01

Present work examines tool steels abrasion wear resistance and the abrasion mechanisms which are one main contributor to failure of tooling in metal forming industry. Tooling used in cutting and metal forming processes without lubrication fails due to this type of wear. In the workshop and engineering practice, it is common to relate wear resistance as function of material hardness only. However, there are others parameters which influences wear such as: fracture toughness, type of crystalline structure and the occurrence of hard precipitate in the metallic matrix and also its nature. In the present investigation, the wear mechanisms acting in tool steels were analyzed and, by normalized tests, wear resistance performance of nine different types of tool steels were evaluated by pin-on-disc testing. Conventional tool steels commonly used in tooling such as AISI H13 and AISI A2 were compared in relation to tool steels fabricated by sintering process such as Crucible CPM 3V, CPM 9V and M4 steels. Friction and wear testing were carried out in a pin-on-disc automated equipment which pin was tool steel and the counter-face was a abrasive disc of silicon carbide. Normal load of 5 N, sliding velocity of 0.45 m/s, total sliding distance of 3000 m and room temperature were employed. The wear rate was calculated by the Archard's equation and from the plotted graphs of pin cumulated volume loss versus sliding distance. Specimens were appropriately heat treated by quenching and three tempering cycles. Percentage of alloying elements, metallographic analyses of microstructure and Vickers microhardness of specimens were performed, analyzed and correlated with wear rate. The work is concluded by the presentation of a rank of tool steel wear rate, comparing the different tool steel abrasion wear resistance: the best tool steel wear resistance evaluated was the Crucible CPM 9V steel.

Thermal Conductivity and Wear Behavior of HVOF-Sprayed Fe-Based Amorphous Coatings

Directory of Open Access Journals (Sweden)

Haihua Yao

2017-10-01

Full Text Available To protect aluminum parts in vehicle engines, metal-based thermal barrier coatings in the form of Fe59Cr12Nb5B20Si4 amorphous coatings were prepared by high velocity oxygen fuel (HVOF spraying under two different conditions. The microstructure, thermal transport behavior, and wear behavior of the coatings were characterized simultaneously. As a result, this alloy shows high process robustness during spraying. Both Fe-based coatings present dense, layered structure with porosities below 0.9%. Due to higher amorphous phase content, the coating H-1 exhibits a relatively low thermal conductivity, reaching 2.66 W/(m·K, two times lower than the reference stainless steel coating (5.85 W/(m·K, indicating a good thermal barrier property. Meanwhile, the thermal diffusivity of amorphous coatings display a limited increase with temperature up to 500 °C, which guarantees a steady and wide usage on aluminum alloy. Furthermore, the amorphous coating shows better wear resistance compared to high carbon martensitic GCr15 steel at different temperatures. The increased temperature accelerating the tribological reaction, leads to the friction coefficient and wear rate of coating increasing at 200 °C and decreasing at 400 °C.

Synthesis and Study on Effect of Parameters on Dry Sliding Wear Characteristics of AL-SI Alloys

Directory of Open Access Journals (Sweden)

Francis Uchenna OZIOKO

2012-08-01

Full Text Available The effect of parameters on dry sliding wear characteristics of Al-Si alloys was studied. Aluminium-silicon alloys containing 7%, 12% and 14% weight of silicon were synthesized using casting method. Dry sliding wear characteristics of sample were studied against a hardened carbon steel (Fe-2.3%Cr-0.9%C using a pin-on-disc. Observations were recorded keeping two parameters (sliding distance, sliding speed and load constant against wear at room temperature. Microstructural characterization was done using optical microscope (OM and scanning electron microscope (SEM. Hardness and wear characteristics of different samples have shown near uniform behaviour. The wear rate decreased when the percentage of silicon increases. Wear was observed to increase at higher applied load, higher sliding speed and higher sliding distance. The wear characteristics of Al-14%Si was observed superior to those of Al-7%Si and Al-12%Si due to the degree of refinement of their eutectic silicon.

Friction and wear behavior of Colmonoy and Stellite alloys in sodium environment

International Nuclear Information System (INIS)

Kanoh, S.; Mizobuchi, S.; Atsumo, H.

1976-01-01

A description is given of a series of experiments in sodium environment for the research and development of friction and wear resistant material used for the sliding components of sodium cooled fast breeder reactor. The study relates to the friction and wear characteristics of nickel-base alloy, Colmonoy, and cobalt-base alloy, Stellite, with respect to temperature, load, sliding velocity, sliding mode, and sodium flushing. The friction behavior of these alloys in sodium is compared with that in argon

Wear determination in braking systems by radioisotopes

International Nuclear Information System (INIS)

Spruch, W.

1979-01-01

Friction and wear behaviour of friction couples has been tested applying loads and sliding speeds. The determination was carried out by direct measurements of the lining material and by surface activation of the opposite material with protons. The application limits of several braking materials could be determined and compared

Characterization of wear mechanism by tribo-corrosion of nickel base alloys

International Nuclear Information System (INIS)

Ionescu, C.C.

2012-01-01

Some components of nuclear power plants, as steam generator tubes are made from Ni base alloys. These components are exposed to severe environment of high temperature and high pressure and submitted to contact mechanical stresses. These Ni - based alloys properties are determined by their ability to form on their surface an inner protective barrier film mainly composed of Cr 2 O 3 . The steam generator tubes are among the most difficult components to maintain, on the hand, because of their safety importance and secondly, the exchange tubes are subject to various degradation mechanisms, because of the harsh conditions of work. Wear by tribo-corrosion is a physicochemical aging mechanism which occurs in the management of the nuclear power plants life time. Tribo-corrosion is an irreversible process which involves mechanical and chemical / electrochemical interactions between surfaces in relative motion, in the presence of a corrosive environment. The goal of this study was to quantify in terms of quantity and quality the wear generated by tribo-corrosion process on Ni - Cr model alloys. Two model alloys: Ni -15Cr and Ni -30Cr were used to highlight, evaluate and compare the influence of the chromium content on the formation of the protective oxide layer and the role played by the latter one on the kinetics and mechanisms of wear by tribo-corrosion. The tribo-corrosion experiments were performed by using a pin-on-disc tribometer under controlled electrochemical conditions in LiOH - H 3 BO 3 solution. The corrosion - wear degradation of the protective layer during continuous and intermittent unidirectional sliding tests was investigated by a three-stage tribo-corrosion protocol. In the first stage, electrochemical techniques (open circuit potential measurements and electrochemical impedance measurements) were used without applying unidirectional sliding to monitor and evaluate the characteristics of protective oxide layer formed on the surface of the two model alloys

Effect of Polypropylene Modification by Impregnation with Oil on Its Wear and Friction Coefficient at Variable Load and Various Friction Rates

Directory of Open Access Journals (Sweden)

Paweł Sędłak

2017-01-01

Full Text Available Laboratorial two-body wear testing was carried out in order to assess effects of polypropylene modification by impregnating it with oils on friction coefficient and wear in comparison to those parameters of unmodified polypropylene, Teflon, and polyamide during operation under conditions of sliding friction without lubrication. Wear behaviour of the tested specimens was investigated using ASTM G77-98 standard wear test equipment. Recording program made it possible to visualise and record the following parameters: rotational speed and load, linear wear, friction coefficient, temperature of the specimen, and ambient temperature. In addition, wear mechanisms of the analysed materials were determined with use of scanning electron microscopy. In the case of the remaining tested polymers, the most important mechanism of wear was adhesion (PP, PTFE, PA 6.6, and PA MoS2, microcutting (PTFE, PA 6.6, and PA MoS2, fatigue wear (PTFE, forming “roll-shaped particles” combined with plastic deformation (PA 6.6 and PA MoS2, and thermal wear (PP. Impregnation of polypropylene with engine oil, gear oil, or RME results in significant reduction of friction coefficient and thus of friction torque, in relation to not only unmodified polypropylene but also the examined polyamide and Teflon.

Negligible heat strain in armored vehicle officers wearing personal body armor

Directory of Open Access Journals (Sweden)

Hunt Andrew P

2011-07-01

Full Text Available Abstract Objectives This study evaluated the heat strain experienced by armored vehicle officers (AVOs wearing personal body armor (PBA in a sub-tropical climate. Methods Twelve male AVOs, aged 35-58 years, undertook an eight hour shift while wearing PBA. Heart rate and core temperature were monitored continuously. Urine specific gravity (USG was measured before and after, and with any urination during the shift. Results Heart rate indicated an intermittent and low-intensity nature of the work. USG revealed six AVOs were dehydrated from pre through post shift, and two others became dehydrated. Core temperature averaged 37.4 ± 0.3°C, with maximum's of 37.7 ± 0.2°C. Conclusions Despite increased age, body mass, and poor hydration practices, and Wet-Bulb Globe Temperatures in excess of 30°C; the intermittent nature and low intensity of the work prevented excessive heat strain from developing.

A method for simultaneous determination of wear-resistance of structurally identical machine parts with mutual friction

International Nuclear Information System (INIS)

Valigura, V.; Volyn'ski, A.

1979-01-01

There are mechanisms in the technique, boundary state of separate parts of which is determined by the process of wear of three elements of the mechanism, made of the same material (for example antifriction bearings). The main concept of wear determination in the case of such a mechanism is to conduct measurements by means of simultaneous application of three different methods, for example: the method of roentgen-fluorescence; the tracer technique with application of activation by means of irradiation by different elementary particles, practically by means of neutrons and protons; the method of artifical bases application. In the paper the method is presented having been developed in the Institute of Working Machines of the Poznan Polytechnic. This method of simultaneous investigation in the wear process of bearing rings, inner and outer, and rolling elements of roller bearings. All these elements of bearings are made of LX-15 steel. The method developed, permits to determine the wear sufficient for practical purposes sensitivity [ru

Effect of La2O3 content on wear resistance of alumina ceramics

Institute of Scientific and Technical Information of China (English)

WU Tingting; ZHOU Jian; WU Bolin; LI Wenjie

2016-01-01

In order to improve the wear resistance, a kind of alumina ceramic with good wear resistance was created in an Al2O3-CaCO3-SiO2-MgO-La2O3 (ACSML) system. The effects of La2O3 content on sintering temperature, bulk density, and wear rate were investigated. The wear rate of sample was as low as 0.0393‰. The wear resistance of the sample containing La2O3 has im-proved 43% than that of the sample without La2O3. Appropriate La2O3 doping could inhibit grain growth, enhance density, and purify grain boundary. La2O3 could diffuse into Al2O3 to form a solid solution and react with Al2O3 to form high-aluminum low-lanthanum complex oxides. The combination among Al2O3, the solid solution layer, and the layer of high-aluminum low-lanthanum complex oxides combined closely, which could improve grain boundary cohesion. Besides, the homogeneous distributions of elements made uniform structure. Finally, the wear resistance of alumina ceramic was improved.

Contact of dual mobility implants: effects of cup wear and inclination.

Science.gov (United States)

Uddin, M S

2015-01-01

Cup wear and inclination on the pelvic bone are significant factors, which change the contact of the articulating surfaces, thus, impacting the long-term performance of hip implants. This paper presents a finite element (FE) analysis of the contact of the dual mobility implants under the influence of cup wear and inclination. A 3D FE model of the implant was developed with the application of equivalent physiological loading and boundary conditions. Effects of cup inclination angle ranging from 45° to 60° and the wear depth ranging from 0 to 2.46 mm equivalent to up to 30 years of the implant's life on the contact pressure and von Mises stress were investigated. Simulation results show that the contact pressure and von Mises stress decrease significantly with a modest wear depth and remains quite in-sensitive to the cup inclination angle and wear depth up to 1.64 mm. With wear depth further up to 2.46 mm, the cup thickness (i.e. cup thinning on worn region) may be more predominant than increasing of contact area between the cup and the head. The wear on the inner surface of the cup is found to rule out the overall contact pressure and stress in the implant. Furthermore, individual and combined effects of both important parameters are analysed and discussed with respect to available clinical/laboratory studies.

Pin on flat wear volume prediction of UHMWPE against cp Ti for orthopedic applications

Science.gov (United States)

Handoko, Suyitno, Dharmastiti, Rini; Magetsari, Rahadyan

2018-04-01

Tribological assessment of orthopedic biomaterials requires a lot of testing time. Researchers must test the biomaterials in millions of cycles at low frequency (1 Hz) to mimic the in vivo conditions. It is a problem because product designs and developments could not wait longer for wear data to predict the lifetime of their products. The problem can be solved with the use of computation techniques to model the wear phenomena and provide predicted data. The aim of this research is to predict the wear volume of the commonly used ultra high molecular weight polyethylene (UHMWPE) sliding against commercially pure titanium (cp Ti) in the unidirectional pin on flat tests. The 9 mm diameter UHMWPE pin and cp Ti plate contact mechanics were modeled using Abaqus. Contact pressure was set at 3 MPa. Outputs of the computations (contact pressure and contact area) were used to calculate the wear volume with Archard law. A custom Python script was made to automate the process. The results were then compared with experimental data for validations. The predicted data were in a good trend with numerical errors from 0.3% up to 26%.

Aplikace pro nositelnou elektroniku se systémem Android Wear

OpenAIRE

Šmejkal, Petr

2017-01-01

Semestrální práce „Aplikace pro nositelnou elektroniku se systémem" Android Wear popisuje základní principy komunikačních sítí - M2M (machine to machine), H2H (human to human) a D2D (device to device). Práce se dále zabývá nositelnými zařízeními, zejména chytrými hodinkami, dostupnými operačními systémy pro chytré hodinky a systémem Android, Android Wear. V praktické části je popsaná funkcionalita, vzhled a struktura vyvinuté aplikace pro Android Wear. The semestral project "Application fo...

Abrasive wear resistance and microstructure of Ni-Cr-B-Si hardfacing alloys with additions of Al, Nb, Mo, Fe, Mn and C

International Nuclear Information System (INIS)

Berns, H.; Fischer, A.; Theisen, W.

1987-01-01

The development of new Ni-base hardfacing alloys for filler wire welding or metal spraying should result in materials with a good resistance against high temperature corrosion and abrasive wear. The first step is to design microstructures, which obtain a satisfactory abrasive wear behaviour at room temperature. Thus, different alloys are melted and scrutinized as to their microstructure and their abrasive wear resistance in laboratory. Compared to commercial Ni-base hardfacing alloys they show a higher volume fraction of coarse hard phases due to the additional, initial solidification of Nb-carbides and Cr-, and Mo-borides. Thus, the abrasive wear resistance is improved. For hard abrasive particles, such as corundum, the Ni-base alloys are more wear resistant than harder Fe-base alloys investigate earlier. This is due to the tougher Ni metal matrix that results in microcracking not to be the most significantly acting wear mechanism

Comparison study on resistance to wear and abrasion of high-temperature sliding strike of laser and plasma spray layer on the stainless steel surface

International Nuclear Information System (INIS)

Shi Shihong; Zheng Qiguang; Fu Geyan; Wang Xinlin

2004-01-01

In this paper, the effect of coatings, which are formed with laser cladding and plasma spray welding on 1Cr18Ni9Ti base metal of nuclear valve seats, on wear resistance is studied. A 5-kW transverse-flowing CO 2 laser is used for cladding Co base alloy powder pre-placed on the substrate. Comparing with the plasma spray coatings, the laser-cladding layer have lower rate of spoiled products and higher rate of finished products. Their microstructure is extremely fine. They have close texture and small-size grain. Their dilution diluted by the compositions of their base metal and hot-effect on base metal are less. The hardness, toughness, and strength of the laser-cladding layers are higher. The grain size is 11-12th grade in the laser-cladding layer and 9-10th in the plasma spray layer. The width of combination zone between laser-cladding layer and substrate is 10-45 μm but that between plasma spray layer and substrate is 120-160 μm. The wear test shows that the laser layers have higher property of anti-friction, anti-scour, and high-temperature sliding strike. The wear resistance of laser-cladding layer is about one time higher than that of plasma spray welding layer

Use of nuclear techniques for measuring thin wears

International Nuclear Information System (INIS)

Jeanneau, B.

1989-01-01

Wear measurements with apparatus of classical metrology like profilography or tridimensional analysis, need a certain number of conditions, in particular, dismantling of the machine into parts, which give less of time and money. Radioactive methods permit to avoid such a dismantling, isn't sensitive to the temperature of the part... and according to their sensitivity, reduce the test duration

Experimental Research on the Determination of the Coefficient of Sliding Wear under Iron Ore Handling Conditions

Directory of Open Access Journals (Sweden)

G. Chen

2017-09-01

Full Text Available The handling of iron ore bulk solids maintains an increasing trend due to economic development. Because iron ore particles have hard composites and irregular shapes, the bulk solids handling equipment surface can suffer from severe sliding wear. Prediction of equipment surface wear volume is beneficial to the efficient maintenance of worn areas. Archard’s equation provides a theoretical solution to predict wear volume. To use Archard’s equation, the coefficient of sliding wear must be determined. To our best knowledge, the coefficient of sliding wear for iron ore handling conditions has not yet been determined. In this research, using a pin-on-disk tribometer, the coefficients of sliding wear for both Sishen particles and mild steel are determined with regard to iron ore handling conditions. Both naturally irregular and spherical shapes of particles are used to estimate average values of wear rate. Moreover, the hardness and inner structures of Sishen particles are examined, which adds the evidence of the interpretation of wear results. It is concluded that the coefficients of sliding wear can vary largely for both Sishen particle and mild steel. The wear rate decreases from transient- to steady-state. The average coefficient of sliding wear is capable of predicting wear with respect to long distances at the steady-state. Two types of sliding friction are distinguished. In addition, it is found that the temperature rise of the friction pairs has negligible influence on wear rate.

Radioisotopic measurement methods for determining the wear railway brake shoe and its rim wearing effect

International Nuclear Information System (INIS)

Doman, P.

1979-01-01

Under operating conditions the wear of brake shoe was tested by a measuring method based on the principle of radioisotopic thickness measurement. It is characteristic to the sensitivity of the method that the wear caused by the fast braking of a train (speed: 100 km/h) as well as the uneven wear distribution were determinable. Surface activating methods assuring the periodic and continuous evaluation were also developed. A test was performed with galvanic surface activation under operating conditions to determine the rim wearing effect of the brake shoe. Apart from the operational tests a new method based on activated wear measurement was also developed. (author)

A Study on Corrosion and Fretting Wear Resistance of Alloy 690 Tubes

Energy Technology Data Exchange (ETDEWEB)

Won, Ju Jin; Min, Su Jung; Kim, Myeong Su; Kim, Kyu Tae [Dongguk Univ., Gyeongju (Korea, Republic of)

2013-10-15

In this article, the effects of such failures have on the materials of alloy 690 are assessed. The corroded volume variation and mass decreased continuously with time. However, the oxide volume changes in an irregular pattern since the oxide formed on the alloy 690 metal may be detached due to the flake formation. The amount of the fretting wear increased with time. It can be seen that the wear rate increased with time and reduced at the later time. The test results show that the ductility decreased as corrosion increases. Alloy 690 is broadly used as a material of nuclear power plant's steam generator tubes because of its excellent mechanical strength, corrosion properties, wear properties and stability at a high temperature. However, the tubes for nuclear power plant's steam generators become a major threat for lifetime management and efficient operation of nuclear power plant due to various corrosion and fretting wear failures caused by flow-induced vibration (FIV) that occurs between tubes.

Wear of resin composites: Current insights into underlying mechanisms, evaluation methods and influential factors

Directory of Open Access Journals (Sweden)

Akimasa Tsujimoto

2018-05-01

Full Text Available Summary: The application of resin composites in dentistry has become increasingly widespread due to the increased aesthetic demands of patients, improvements in the formulation of resin composites, and the ability of these materials to bond to tooth structures, together with concerns about dental amalgam fillings. As resistance to wear is an important factor in determining the clinical success of resin composite restoratives, this review article defines what constitutes wear and describes the major underlying phenomena involved in this process. Insights are further included on both in vivo and in vitro tests used to determine the wear resistance of resin composite and the relationships between these tests. The discussion focuses on factors that contribute to the wear of resin composite. Finally, future perspectives are included on both clinical and laboratory tests and on the development of resin composite restorations. Keywords: Resin composites, Wear resistance, Wear testing

Research on the effect of wear-ring clearances to the axial and radial force of a centrifugal pump

International Nuclear Information System (INIS)

Zhao, W G; Qi, C X; Li, Y B; He, M Y

2013-01-01

Varying of the wear-ring clearance not only has a distinct effect on the volumetric loss of the centrifugal pump, but also on the performance of the centrifugal pump including the axial and radial forces. Comparing with the experimental studies, numerical simulation methods have some special advantages, such as the low cost, fast and high efficiency, and convenient to get the detailed structure of the internal flow characteristics, so it has been widely used in the fluid machinery study in recent years. In order to study the effect of wear-ring clearance on the force performance of the centrifugal pump, based on the Reynolds Time-Averaged N-S equations and RNG k-ε turbulence model, a centrifugal pump with three variable styles of the wear-rings was simulated: Only the clearance of the front wear-ring was changed, only the clearance of the back wear-ring was changed and both were changed. Comparing with the experiment, numerical results show a good agreement. In the three changing styles of the clearance, the variable of the clearance of front wear-ring has the most influence on the axial force of the centrifugal pump, while has tiny effect on the radial force for all the conditions

Effects of cryogenic treatment on the wear properties of brake discs

Science.gov (United States)

Nadig, D. S.; Shivakumar, P.; Anoop, S.; Chinmay, Kulkarni; Divine, P. V.; Harsha, H. P.

2017-02-01

Disc brakes are invariably used in all the automobiles either to reduce the rotational speed of the wheel or to hold the vehicle stationary. During the braking action, the kinetic energy is converted into heat which can result in high temperatures resulting in fading of brake effects. Brake discs produced out of martensite stainless steel (SS410) are expected to exhibit high wear resistance properties with low value of coefficient of friction. These factors increase the useful life of the brake discs with minimal possibilities of brake fade. To study the effects of cryogenic treatment on the wear behaviour, two types of brake discs were cryotreated at 98K for 8 and 24 hours in a specially developed cryotreatment system using liquid nitrogen. Wear properties of the untreated and cryotreated test specimens were experimentally determined using the pin on disc type tribometer (ASTM G99-95). Similarly, the Rockwell hardness (HRC) of the specimens were tested in a hardness tester in accordance with ASTM E18. In this paper, the effects of cryotreatment on the wear and hardness properties of untreated and cryotreated brake discs are presented. Results indicate enhancement of wear properties and hardness after cryogenic treatment compared with the normal brakes discs.

Nodal wear model: corrosion in carbon blast furnace hearths

International Nuclear Information System (INIS)

Verdeja, L. F.; Gonzalez, R.; Alfonso, A.; Barbes, M. F.

2003-01-01

Criteria developed for the Nodal Wear Model (NWM) were applied to estimate the shape of the corrosion profiles that a blast furnace hearth may acquire during its campaign. Taking into account design of the hearth, the boundary conditions, the characteristics of the refractory materials used and the operation conditions of the blast furnace, simulation of wear profiles with central well, mushroom and elephant foot shape were accomplished. The foundations of the NWM are constructed considering that the corrosion of the refractory is a function of the temperature present at each point (node) of the liquid metal-refractory interface and the corresponding physical and chemical characteristics of the corrosive fluid. (Author) 31 refs

The validity of Actiwatch2 and SenseWear armband compared against polysomnography at different ambient temperature conditions

Directory of Open Access Journals (Sweden)

Mirim Shin

2015-01-01

Full Text Available There were no validation studies on portable sleep devices under different ambient temperature, thus this study evaluated the validity of wrist Actiwatch2 (AW2 or SenseWear armband (SWA against polysomnography (PSG in different ambient temperatures. Nine healthy young participants (6 males, aged 23.3±4.1 y underwent nine nights of study at ambient temperature of 17 °C, 22 °C and 29 °C in random order, after an adaptation night. They wore the AW2 and SWA while being monitored for PSG simultaneously. A linear mixed model indicated that AW2 is valid for sleep onset latency (SOL, total sleep time (TST and sleep efficiency (SE but significantly overestimated wake after sleep onset (WASO at 17 °C and 22 °C. SWA is valid for WASO, TST and SE at these temperatures, but severely underestimates SOL. However, at 29 °C, SWA significantly overestimated WASO and underestimated TST and SE. Bland–Altman plots showed small biases with acceptable limits of agreement (LoA for AW2 whereas, small biases and relatively wider LoA for most sleep variables were observed in SWA. The kappa statistic showed a moderate sleep–wake epoch agreement, with a high sensitivity but poor specificity; wake detection remains suboptimal. AW2 showed small biases for most of sleep variables at all temperature conditions, except for WASO. SWA is reliable for measures of TST, WASO and SE at 17–22 °C but not at 29 °C, and SOL approximates that of PSG only at 29 °C, thus caution is needed when monitoring sleep at different temperatures, especially in home sleep studies, in which temperature conditions are more variable.

Nuclear Fuel Fretting Mechanisms in a Room Temperature Unlubricated Condition

Energy Technology Data Exchange (ETDEWEB)

Lee, Young Ho; Kim, Hyung Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2008-10-15

Recently, efforts for evaluating the fretting wear mechanism have been carried out by many researchers in various conditions. In an unlubricated condition, especially, effects of a wear debris and/or its layer on the fretting wear behavior were proposed that the formation of a well-developed glaze layer has a beneficial effect for decreasing a friction coefficient. Otherwise, a wear rate was accelerated by a third-body abrasion. At this time, it is well known that wear debris behaviors are affected by test variables such as a temperature, environment, material characteristics, etc. In a nuclear fuel fretting, however, its contact condition is quite different when compared with general fretting wear studies and could be summarized as the following; first, a fuel rod is supported by spacer grid springs and dimples that were elastically deformable. This results in a unique friction loop and a different fretting mechanism when a fuel rod is vibrated due to a flow-induced vibration (FIV). Next, it is possible that some region of the wear scar area with a specific spring shape condition could be hidden due to different wear debris behavior. So, some of the wear debris layers could be found on the worn surfaces in previous studies even though fretting wear tests were performed in a water lubricated condition. Finally, initial contact condition could be changed both an actual operating condition in power plants (i.e. high temperature and pressurized water (HTHP) under severe irradiation conditions) and the fretting wear tests for evaluating the wear resistant spring in lab conditions (i.e. from room temperature to HTHP without irradiation conditions) due to material degradations and the formation of the wear scar, respectively. In summary, the spring shape effect and the variation of the contact condition with increasing fretting cycle should be evaluated in order to improve the wear resistance of the spacer grid spring. So, in this study, fretting wear tests have been

Dry Sliding Wear Behavior of Super Duplex Stainless Steel AISI 2507: a Statistical Approach

Directory of Open Access Journals (Sweden)

Davanageri M.

2016-12-01

Full Text Available The dry sliding wear behavior of heat-treated super duplex stainless steel AISI 2507 was examined by taking pin-on-disc type of wear-test rig. Independent parameters, namely applied load, sliding distance, and sliding speed, influence mainly the wear rate of super duplex stainless steel. The said material was heat treated to a temperature of 850°C for 1 hour followed by water quenching. The heat treatment was carried out to precipitate the secondary sigma phase formation. Experiments were conducted to study the influence of independent parameters set at three factor levels using the L27 orthogonal array of the Taguchi experimental design on the wear rate. Statistical significance of both individual and combined factor effects was determined for specific wear rate. Surface plots were drawn to explain the behavior of independent variables on the measured wear rate. Statistically, the models were validated using the analysis of variance test. Multiple non-linear regression equations were derived for wear rate expressed as non-linear functions of independent variables. Further, the prediction accuracy of the developed regression equation was tested with the actual experiments. The independent parameters responsible for the desired minimum wear rate were determined by using the desirability function approach. The worn-out surface characteristics obtained for the minimum wear rate was examined using the scanning electron microscope. The desired smooth surface was obtained for the determined optimal condition by desirability function approach.

Resistance to wear and microstructure of martensitic welds deposits for recharge

International Nuclear Information System (INIS)

Gualco, Agustin; Svoboda, Hernan G; Surian, Estela S; Vedia, Luis A

2006-01-01

This work studied the welding metal for a martensitic steel (alloyed to Cr, Mn, Mo, V and W), deposited with a tubular metal-cored wire with gaseous protection of 82%Ar-18%Co 2 on a low carbon steel using the semi-automatic welding process. Transverse pieces were cut from the welded coupon for microstructural characterization, measurement of hardness profiles, determination of the chemical composition and wear trials. The microstructural characterization was done using optic and scanning electronic microscopes, X-rays diffraction and energy-dispersive X-ray spectroscopy and Vicker microhardness (1 kg.) was measured. The wear trials (metal-metal) were performed in an Amsler machine under pure flow conditions. Different loads were used and the reference material was a SAE 1020 steel. The temperatures for each case were measured and the weight loss curves were defined as a function of the distance run and of the load. After testing the wear surfaces and the debris were measured. The microstructure of the welded deposit mostly consists of martensite and some retained austenite, with a pattern of dendritic segregation, and a hardness on the surface of 612 HVI. A lineal variation between the weight loss and the load applied was obtained as a response to the wear. The following phenomena were observed: abrasion, plastic deformation, oxidation and adhesion to the wear surfaces, as well as a tempering effect in the condition of the biggest load. The wear mechanisms acting on both surfaces were identified (CW)

Microstructure and wear properties of the electroslag remelting layer reinforced by TiC particles

Institute of Scientific and Technical Information of China (English)

无

2008-01-01

The electroslag remelting (ESR) layer reinforced by TiC particles was obtained by electroslag remelting.The microstructure and wear properties of the ESR layer were studied by means of scanning electron microscopy (SEM),X-ray diffraction (XRD),and wear test.The results indicate that TiC particles are synthesized by self-propagating high-temperature synthesis (SHS) reaction during the electroslag remelting process.The size of TiC particles is in the range of 1-10 μm,and the distribution of TiC particles is uniform,from outside to inside of the ESR layer,and the volume fraction and the size of TiC particles decrease gradually.Molten iron and slag flow into porosity due to the SHS process leading to rapid densification and the elimination of porosity in the ESR layer during the ESR process.TiC particles enhance the wear resistance of the ESR layer,whereas CaF2 can improve the high temperature lubricating property of the ESR layer.

A kinetic model for impact/sliding wear of pressurized water reactor internal components: Application to rod cluster control assemblies

International Nuclear Information System (INIS)

Zbinden, M.

1996-01-01

Certain internal components of Pressurized Water Reactors are damaged by wear when subjected to vibration induced by flow. In order to enable predictive calculation of such wear, one must have a model which takes account reliably of real damages. The modelling of wear represents a final link in a succession of numerical calculations which begins by the determination of hydraulic excitations induced by the flow. One proceeds, then, in the dynamic response calculation of the structure to finish up with an estimation of volumetric wear and of the depth of wear scars. A new concept of industrial wear model adapted to components of nuclear plants is proposed. Its originality is to be supported, on one hand, by experimental results obtained via wear machines of relatively short operational times, and, on the other hand, by the information obtained from the operating feedback over real wear kinetics of the reactors components. The proposed model is illustrated by an example which correspond to a specific real situation. The determination of the coefficients permitting to cover all assembly of configurations and the validation of the model in these configurations have been the object of the most recent work

Determination of a Wear Initiation Cycle by using a Contact Resistance Measurement in Nuclear Fuel Fretting

International Nuclear Information System (INIS)

Lee, Young Ho; Kim, Hyung Kyu

2008-01-01

In nuclear fuel fretting, the improving of the contact condition with a modified spring shape is a useful method for increasing the wear resistance of the nuclear fuel rod. This is because the fretting wear resistance between the fuel rod and grid spring is mainly affected by the grid spring shape rather than the environment, the contact modes, etc. In addition, the wear resistance is affected by the wear debris behavior between contact surfaces. So, it is expected that the wear initiation of each spring shape should be determined in order to evaluate a wear resistance. However, it is almost impossible to measure the wear behavior in contact surfaces on a real time basis because the contact surfaces are always hidden. Besides, the results of the worn surface observation after the fretting wear tests are restricted to archive the information on the wear debris behavior and the formation mechanism of the wear scar. In order to evaluate the wear behavior during the fretting wear tests, it is proposed that the contact resistance measurement is a useful method for examining the wear initiation cycle and modes. Generally, fretting wear damages are rapidly progressed by a localized plastic deformation between the contact surfaces, crack initiation and fracture of the deformed surface with a strain hardening difference between a surface and a subsurface and finally a detachment of wear debris. After this, wear debris is easily oxidized by frictional heat, test environment, etc. At this time, a small amount of electric current applied between the contact surfaces will be influenced by the wear debris, which could be an obstacle to an electric current flow. So, it is possible to archive the information on the wear behavior by measuring the contact resistance. In order to determine the wear initiation cycle during the fretting wear tests, in this study, fretting wear tests have been performed by applying a constant electric current in room temperature air

Multidisciplinary Investigations Regarding the Wear of Machine Tools Operating Into the Soil

Science.gov (United States)

Cardei, P.; Vladutoiu, L. C.; Gheorghe, G.; Fechete, T. L. V.; Chisiu, G.

2018-01-01

The paper presents the results obtained by the authors in investigating the problem of wear of work organs of machines working in continuous interaction with the soil. The phenomenon of the interaction of the tools of agricultural machinery for ploughing, and the soil, is a complex of phenomena, one of the most difficult to model. Among the phenomena involved in this interaction, friction and wear (of many types) are the most important. We did not take into account the chemical wear, and by the wear caused by weather conditions. Research has focused on formulating a theory that has more than a descriptive character, for it be used for application purposes. For this we used classical theoretical models, mathematical models based on the theory of continuous bodies, theory of flow of fluids around the profiles, as well as other theories, approached or not, in an attempt to solve as satisfactorily the issue of the wear, for the tools of the agricultural machines for the tillage. We also sought to highlight the fact that wear is a phenomenon on a micro and macro-scale scale, and its generating causes must ultimately be related to observable effects, on the macro-structural scale.

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.

Recent developments in the use of plastic optical fiber for an embedded wear sensor

Science.gov (United States)

Cohen, Edward I.; Mastro, Stephen A.; Nemarich, Christopher P.; Korczynski, Joseph F., Jr.; Jarrett, Andrew W.; Jones, Wayne C.

1999-05-01

This paper describes recent developments of a practical, low cost embedded plastic optical fiber (POF) wear sensor system for the condition based maintenance of external outboard water lubricated bearings aboard U.S. Navy Ships. The benefit of this measurement system over the status quo is the ability to remotely monitor bearing wear. The Embedded Wear Sensor system (Navy invention disclosure #78,570) features a sacrificial wear fiber embedded into the nitrile rubber bearing. This fiber may also act as a conduit for the transmission of pressure and temperature data that may be resolved into alignment data. The authors selected a commercially-off-the- shelf plastic fiber for the sensor because of its material compatibility with the nitrile rubber bearing staves in terms of flexural modulus and wear properties. Presented herein is a description of the system concept, the results of non-linear finite element analysis, market survey of POF, mold studies, small scale prototyping and abrasive wear testing. A description of the sensor concept and the results of the preliminary finite element analysis of the bearing stave geometry are presented. Preliminary results of molding and glue bonding POF in nitrile rubber and then abrasive wear testing indicate that this is a viable concept.

Wear behavior of AA 5083/SiC nano-particle metal matrix composite: Statistical analysis

Science.gov (United States)

Hussain Idrisi, Amir; Ismail Mourad, Abdel-Hamid; Thekkuden, Dinu Thomas; Christy, John Victor

2018-03-01

This paper reports study on statistical analysis of the wear characteristics of AA5083/SiC nanocomposite. The aluminum matrix composites with different wt % (0%, 1% and 2%) of SiC nanoparticles were fabricated by using stir casting route. The developed composites were used in the manufacturing of spur gears on which the study was conducted. A specially designed test rig was used in testing the wear performance of the gears. The wear was investigated under different conditions of applied load (10N, 20N, and 30N) and operation time (30 mins, 60 mins, 90 mins, and 120mins). The analysis carried out at room temperature under constant speed of 1450 rpm. The wear parameters were optimized by using Taguchi’s method. During this statistical approach, L27 Orthogonal array was selected for the analysis of output. Furthermore, analysis of variance (ANOVA) was used to investigate the influence of applied load, operation time and SiC wt. % on wear behaviour. The wear resistance was analyzed by selecting “smaller is better” characteristics as the objective of the model. From this research, it is observed that experiment time and SiC wt % have the most significant effect on the wear performance followed by the applied load.

Effect of mechanical vibrations on the wear behavior of AZ91 Mg alloy

Science.gov (United States)

Chaturvedi, V.; Pandel, U.; Sharma, A.

2018-02-01

AZ91 Mg alloy is the most promising alloy used for structural applications. The vibration induced methods are effective and economic viable in term of mechanical properties. Sliding wear tests were performed on AZ91 Mg alloy using a pin-on- disc configuration. Wear rates were measured at 5 N and 10N at a sliding velocity of 1m/s for varied frequency within the range of 5- 25Hz and a constant amplitude of 2mm. Microstructures of worn surfaces and wear debris were characterized by field emission scanning electron microscopy (FESEM). It is observed that wear resistance of vibrated AZ91 alloy at 15Hz frequency ad 2mm amplitude was superior than cast AZ91 Mg alloy. Finer grain size and equiaxed grain shape both are important parameters for better wear resistance in vibrated AZ91 Mg alloys. FESEM analysis revealed that wear is considerably affected due to frictional heat generated by the relative motion between AZ91 Mg alloy and EN31 steel surface. No single mechanism was responsible for material loss.

MICROSTRUCTURE, THERMO-PHYSICAL, MECHANICAL AND WEAR PROPERTIES OF IN-SITU FORMED BORON CARBIDE - ZIRCONIUM DIBORIDE COMPOSITE

Directory of Open Access Journals (Sweden)

T. S. R. Ch. Murthy

2017-12-01

Full Text Available Microstructure, thermos-physical, mechanical and wear properties of in-situ formed B₄C- ZrB₂ composite were investigated. Coefficient of thermal expansion, thermal diffusivity and electrical resistivity of the composite were measured at different temperatures up to 1000 °C in inert atmosphere. Flexural strength was measured up to 900 °C in air. Friction and wear properties have been studied at different loads under reciprocative sliding, using a counter body (ball of cemented tungsten carbide (WC-Co at ambient conditions. X-ray diffraction (XRD and electron probe microanalysis (EPMA confirmed the formation of ZrB₂ as the reaction product in the composite. Electrical resistivity was measured as 3.02 x 10-4Ω.m at 1000°C. Thermal conductivity measured at temperatures between 25°C and 1000 °C was in the range of 8 to 10 W/m-K. Flexural strength of the composite decreased with increase in temperature and reached a value of 92 MPa at 900°C. The average value of coefficient of friction (COF was measured as 0.15 at 20 N load and 10 Hz frequency. Increase of load from 5 N to 20 N resulted in decrease in COF from 0.24 to 0.15 at 10 Hz frequency. Specific wear rate data observed was of the order of 10-6 mm³/N-m. Both abrasive and tribo-chemical reaction wear mechanisms were observed on the worn surface of flat and counter body materials. At higher loads (≥10 N a tribo-chemical reaction wear mechanism was dominant.

Application of radionuclide techniques to study the wear behaviour of peripherally treated and coated components

International Nuclear Information System (INIS)

Hirsch, E.; Mayer, K.H.; Rodrian, U.; Scheidemantel, N.; Schweizer, R.

1990-07-01

Technically and economically important machinery components (helical gear wheels, camshafts, rams, valve rockers) were to be optimized with regard to their wear behaviour under operation-oriented load conditions, and the process parameters required both for peripheral layer heating and surface coating were to be determined. Based on earlier experiments, the treatment parameters and the basic materials were varied. The layer structure was studied, characterized and correlated wi the wear behaviour. The wearing parts were activated in the reactor by thermal neutrons, or in the cyclotron by charged particles. By labelling various parts by means of different radioisotopes, up to three components may be measured at the same time in practice, provided that the circumstances are favourable. (BBR) [de

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.

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

Determination of rail wear and short-time wear measurements of rails applying radioisotopes

International Nuclear Information System (INIS)

Grohmann, H.D.

1981-01-01

An energetic model has been developed for calculating rail wear. Short-time wear tests on rails after surface activation and following activity measurements showed a good agreement with the calculated values

Tribological and Wear Performance of Carbide Tools with TiB2 PVD Coating under Varying Machining Conditions of TiAl6V4 Aerospace Alloy

Directory of Open Access Journals (Sweden)

Jose Mario Paiva

2017-11-01

Full Text Available Tribological phenomena and tool wear mechanisms during machining of hard-to-cut TiAl6V4 aerospace alloy have been investigated in detail. Since cutting tool wear is directly affected by tribological phenomena occurring between the surfaces of the workpiece and the cutting tool, the performance of the cutting tool is strongly associated with the conditions of the machining process. The present work shows the effect of different machining conditions on the tribological and wear performance of TiB2-coated cutting tools compared to uncoated carbide tools. FEM modeling of the temperature profile on the friction surface was performed for wet machining conditions under varying cutting parameters. Comprehensive characterization of the TiB2 coated vs. uncoated cutting tool wear performance was made using optical 3D imaging, SEM/EDX and XPS methods respectively. The results obtained were linked to the FEM modeling. The studies carried out show that during machining of the TiAl6V4 alloy, the efficiency of the TiB2 coating application for carbide cutting tools strongly depends on cutting conditions. The TiB2 coating is very efficient under roughing at low speeds (with strong buildup edge formation. In contrast, it shows similar wear performance to the uncoated tool under finishing operations at higher cutting speeds when cratering wear predominates.

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

Comparison of various tool wear prediction methods during end milling of metal matrix composite

Science.gov (United States)

Wiciak, Martyna; Twardowski, Paweł; Wojciechowski, Szymon

2018-02-01

In this paper, the problem of tool wear prediction during milling of hard-to-cut metal matrix composite Duralcan™ was presented. The conducted research involved the measurements of acceleration of vibrations during milling with constant cutting conditions, and evaluation of the flank wear. Subsequently, the analysis of vibrations in time and frequency domain, as well as the correlation of the obtained measures with the tool wear values were conducted. The validation of tool wear diagnosis in relation to selected diagnostic measures was carried out with the use of one variable and two variables regression models, as well as with the application of artificial neural networks (ANN). The comparative analysis of the obtained results enable.

Feasibility of wear compensation in micro EDM milling based on discharge counting and discharge population characterization

DEFF Research Database (Denmark)

Bissacco, Giuliano; Hansen, Hans Nørgaard; Tristo, G.

2011-01-01

This paper investigates the applicability of real time wear compensation in micro EDM milling based on discharge counting and discharge population characterization. Experiments were performed involving discharge counting and tool electrode wear measurement in a wide range of process parameters...

Onset wear in self-assembled monolayers

International Nuclear Information System (INIS)

D'Acunto, Mario

2006-01-01

Self-assembled monolayers (SAMs) are very useful for the systematic modification of the physical, chemical and structural properties of a surface by varying the chain length, tail group and composition. Many of these properties can be studied making use of atomic force microscopy (AFM), and the interaction between the AFM probe tip and the SAMs can also be considered an excellent reference to study the fundamental properties of dissipation phenomena and onset wear for viscoelastic materials on the nanoscale. We have performed a numerical study showing that the fundamental mechanism for the onset wear is a process of nucleation of domains starting from initial defects. An SAM surface repeatedly sheared by an AFM probe tip with enough applied loads shows the formation of progressive damages nucleating in domains. The AFM induced surface damages involve primarily the formation of radicals from the carbon chain backbones, but the deformations of the chains resulting in changes of period lattice also have to be taken into consideration. The nucleation of the wear domains generally starts at the initial surface defects where the energy cohesion between chains is lower. Moreover, the presence of surface defects is consistent with the changes in lateral force increasing the probability of the activation for the removal of carbon debris from the chain backbone. The quantification of the progressive worn area is performed making use of the Kolmogorov-Johnson-Mehl-Avrami (KJMA) theory for phase transition kinetic processes. The advantage of knowing the general conditions for onset wear on the SAM surfaces can help in studying the fundamental mechanisms for the tribological properties of viscoelastic materials, in solid lubrication applications and biopolymer mechanics

Wear mechanisms in ceramic hip implants.

Science.gov (United States)

Slonaker, Matthew; Goswami, Tarun

2004-01-01

The wear in hip implants is one of the main causes for premature hip replacements. The wear affects the potential life of the prosthesis and subsequent removals of in vivo implants. Therefore, the objective of this article is to review various joints that show lower wear rates and consequently higher life. Ceramics are used in hip implants and have been found to produce lower wear rates. This article discusses the advantages and disadvantages of ceramics compared to other implant materials. Different types of ceramics that are being used are reviewed in terms of the wear characteristics, debris released, and their size together with other biological factors. In general, the wear rates in ceramics were lower than that of metal-on-metal and metal-on-polyethylene combinations.

Wear of control rod cluster assemblies and of instrumentation thimbles: first results obtained with the vibrateau wear simulator

International Nuclear Information System (INIS)

Zbinden, M.; Hersant, D.

1993-07-01

Several REP components are affected by a particular sort of damage called impact/sliding wear. This kind of wear, originating from flow induced vibrations, affects loosely supported tubular structures. The main involved components are: - the RCCAs claddings and the guides tubes, - the instrumentation thimbles, - the fuel rods claddings, - the SG tubes. The R and D Division is concerned with studies aiming to understand and to master the phenomena leading to this wear. The MTC Branch is charged of the study of the wear itself. Tests are carried out on wear rigs to understand and to model wear mechanisms. The following work is related to the two first wear tests campaigns on the VIBRATEAU wear simulator: - a reproducibility test series in order to assess the spreading of the experimental results, - a comparative test series on surface treatments used to improve the components war resistance. (authors). 7 figs., 2 tabs., 4 refs

Effect of hexagonal boron nitride and calcined petroleum coke on friction and wear behavior of phenolic resin-based friction composites

International Nuclear Information System (INIS)

Yi Gewen; Yan Fengyuan

2006-01-01

Calcined petroleum coke (CPC) and hexagonal boron nitride (h-BN) were used as the friction modifiers to improve the friction and wear properties of phenolic resin-based friction composites. Thus, the composites with different relative amounts of CPC and h-BN as the friction modifiers were prepared by compression molding. The hardness and bending strength of the friction composites were measured. The friction and wear behaviors of the composites sliding against cast iron at various temperatures were evaluated using a pin-on-disc test rig. The worn surfaces and wear debris of the friction composites were analyzed by means of scanning electron microscopy, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. It was found that the hybrid of the two friction modifiers was effective to significantly decrease the wear rate and stabilize the friction coefficient of the friction composites at various temperatures by forming a uniform lubricating and/or transferred film on the rubbing surfaces. The uniform and durable transfer films were also able to effectively diminish the direct contact between the friction composite and the cast iron counterpart and hence prevent severe wear of the latter as well. The effectiveness of the hybrid of CPC and h-BN in improving the friction and wear behavior of the phenolic resin-based friction modifiers could be attributed to the complementary action of the 'low temperature' lubricity of CPC and the 'high temperature' lubricity of h-BN. The optimum ratio of the two friction modifiers CPC and h-BN in the friction composites was suggested to be 1:1, and the corresponding friction composite showed the best friction-reducing and antiwear abilities

Wear resistance of TiB/sub 2/-Fe cermets

International Nuclear Information System (INIS)

Champagne, B.; Dallaire, S.

1985-01-01

A material which consists of TiB/sub 2/ dispersed in an iron matrix was synthesized by the exothermic reaction of ferrotitanium and boron. The as-reacted products were hot isostatically pressed to produce TiB/sub 2/-Fe cermets. The influence of HIP variables on the density and total fractional porosity of specimens is presented. Density above 95% is obtained by HIPping at temperatures below 1300 0 C. Increasing the temperature and the time of HIPping enhance the mechanical properties and wear resistance of TiB/sub 2/-Fe cermets by reducing their residual porosity. Relations obtained by regression analysis showed that the porosity strongly affects the properties of parts. Regression analysis point out that the wear loss of a 5% porosity TiB/sub 2/-Fe cermet is 270% higher than a dense HIPped cermet. Low stress and high stress abrasion resistance tests utilizing various abrasive media were carried out on dense HIPped cermets and results were compared with those obtained from WC-Co cermets and 1020 steel

Dry sliding wear behaviour of Al-12Si-4Mg alloy with cerium addition

International Nuclear Information System (INIS)

Anasyida, A.S.; Daud, A.R.; Ghazali, M.J.

2010-01-01

The purpose of this work is to understand the effect of cerium addition on wear resistance behaviour of as-cast alloys. Al-12Si-4 Mg alloys with 1-5 wt% cerium addition were prepared using the casting technique. A sliding wear test was carried out under applied loads of 10 N, 30 N and 50 N at a fixed sliding speed of 1 m/s using a pin-on-disc configuration. The wear test was conducted in dry conditions at room temperature of ∼25 o C. Detailed analysis of the microstructure, worn surface, collected debris and microhardness was undertaken in order to investigate the differences between the as-cast alloys with different levels of cerium addition. The addition of 1-5 wt% cerium was found to lead to the precipitation of intermetallic phases (Al-Ce), resulting a needle-like structures. Increasing cerium content up to 2 wt% improved both wear resistance and microhardness of as-cast alloys. Addition of more than 2 wt% cerium, however, led to a decrease in microhardness, resulting in lower wear resistance of the alloys. Moderate wear was observed at all loads, with specific wear rates (K') ranging from 6.82 x 10 -5 with 2 wt% Ce at applied load of 50 N to 21.48 x 10 -5 mm 3 /N m without added Ce at an applied load of 10 N. Based on K' ranges, the as-cast alloys exhibited moderate wear regimes, and the mechanism of wear is a combination of abrasion and adhesion. Alloy containing 2 wt% Ce, with the highest hardness and lowest K' value, showed the greatest wear resistance.

Characteristics of fracture during the approach process and wear mechanism of a silicon AFM tip

International Nuclear Information System (INIS)

Chung, Koo-Hyun; Lee, Yong-Ha; Kim, Dae-Eun

2005-01-01

The wear of an atomic force microscope (AFM) tip is one of the crucial issues in AFM as well as in other probe-based applications. In this work, wear tests under extremely low normal load using an AFM were conducted. Also, in order to understand the nature of silicon tip wear, the wear characteristics of crystal silicon and amorphous silicon oxide layer were investigated by a high-resolution transmission electron microscope (HRTEM). It was found that fracture of the tip readily occurred due to impact during the approach process. Experimental results showed that the impact should be below 0.1 nN s to avoid significant fracture of the tip. Also, it was observed that wear of the amorphous layer, formed at the end of the tip, occurred at the initial stage of the silicon tip damage process. Based on Archard's wear law, the wear coefficient of the amorphous layer was in the range of 0.009-0.014. As for the wear characteristics of the silicon tip, it was shown that wear occurred gradually under light normal load and the wear rate decreased with increase in the sliding distance. As for the wear mechanism of the silicon tip, oxidation wear was identified to be the most significant. It was shown that the degree of oxidation was higher under high normal load and in a nitrogen environment, oxidation of the silicon tip was reduced

Tribological properties of PM212: A high-temperature, self-lubricating, powder metallurgy composite

Science.gov (United States)

Dellacorte, Christopher; Sliney, Harold E.

1989-01-01

This paper describes a research program to develop and evaluate a new high temperature, self-lubricating powder metallurgy composite, PM212. PM212 has the same composition as the plasma-sprayed coating, PS212, which contains 70 wt percent metal-bonded chromium carbide, 15 wt percent silver and 15 wt percent barium fluoride/calcium fluoride eutectic. The carbide acts as a wear resistant matrix and the silver and fluorides act as low and high temperature lubricants, respectively. The material is prepared by sequential cold press, cold isostatic pressing and sintering techniques. In this study, hemispherically tipped wear pins of PM212 were prepared and slid against superalloy disks at temperatures from 25 to 850 C in air in a pin-on-disk tribometer. Friction coefficients range from 0.29 to 0.38 and the wear of both the composite pins and superalloy disks was moderate to low in the 10(exp -5) to 10(exp -6) cubic mm/N-m range. Preliminary tests indicate that the material has a compressive strength of at least 130 MPa over the entire temperature range of 25 to 900 C. This material has promise for use as seal inserts, bushings, small inside diameter parts and other applications where plasma-sprayed coatings are impractical or too costly.

Tribological properties of PM212 - A high temperature, self-lubricating, powder metallurgy composite

Science.gov (United States)

Dellacorte, Christopher; Sliney, Harold E.

1990-01-01

This paper describes a research program to develop and evaluate a new high temperature, self-lubricating powder metallurgy composite, PM212. PM212 has the same composition as the plasma-sprayed coating, PS212, which contains 70 wt percent metal-bonded chromium carbide, 15 wt percent silver and 15 wt percent barium fluoride/calcium fluoride eutectic. The carbide acts as a wear resistant matrix and the silver and fluorides act as low and high temperature lubricants, respectively. The material is prepared by sequential cold press, cold isostatic pressing and sintering techniques. In this study, hemispherically tipped wear pins of PM212 were prepared and slid against superalloy disks at temperatures from 25 to 850 C in air in a pin-on-disk tribometer. Friction coefficients range from 0.29 to 0.38 and the wear of both the composite pins and superalloy disks was moderate to low in the 10(exp -5) to 10(exp -6) cubic mm/N-m range. Preliminary tests indicate that the material has a compressive strength of at least 130 MPa over the entire temperature range of 25 to 900 C. This material has promise for use as seal inserts, bushings, small inside diameter parts and other applications where plasma-sprayed coatings are impractical or too costly.

Applications of high-temperature superconductivity

International Nuclear Information System (INIS)

Malozemoff, A.P.; Gallagher, W.J.; Schwall, R.E.

1987-01-01

The new high temperature superconductors open up possibilities for applications in magnets, power transmission, computer interconnections, Josephson devices and instrumentation, among many others. The success of these applications hinges on many interlocking factors, including critical current density, critical fields, allowable processing temperatures, mechanical properties and chemical stability. An analysis of some of these factors suggests which applications may be the easiest to realize and which may have the greatest potential

Dry Sliding Wear Behavior of Spark Plasma Sintered Fe-Based Bulk Metallic Glass/Graphite Composites

Directory of Open Access Journals (Sweden)

Xiulin Ji

2016-09-01

Full Text Available Bulk metallic glass (BMG and BMG-graphite composites were fabricated using spark plasma sintering at the sintering temperature of 575 °C and holding time of 15 min. The sintered composites exhibited partial crystallization and the presence of distributed porosity and graphite particles. The effect of graphite reinforcement on the tribological properties of the BMG/graphite composites was investigated using dry ball-on-disc sliding wear tests. The reinforcement of graphite resulted in a reduction in both the wear rate and the coefficient of friction as compared to monolithic BMG samples. The wear surfaces of BMG/graphite composites showed regions of localized wear loss due to microcracking and fracture, as was also the case with the regions covered with graphite-rich protective film due to smearing of pulled off graphite particles.

Numerical study of the influence of the thickness and roughness of TiN coatings on their wear in scratch testing

Science.gov (United States)

Eremina, G. M.; Smolin, A. Yu.

2017-12-01

One of the mostly used and complicated surgical operations on large human joints is total hip replacement. An endoprosthesis is chosen individually for each person on the basis of his anatomical features and physical activity. However, such an important factor affecting the durability of an endoprosthesis as wear in the head-acetabular cup friction pair is still poorly understood, and it is taken into account only qualitatively. The determining role in wear belongs to the structure of the surface layers and coatings of the friction pair. The mechanical and structural characteristics of the coating largely depend on the method of its application. In this paper, to study the tribological characteristics of the coating material of the friction pair, we use computer simulation of scratch testing. The simulations are performed with the application of the method of movable cellular automata. The model specimens correspond to real coatings manufactured under different treatment conditions (deposition temperature and time). The analysis of the simulation results allows one to choose the optimal regime corresponding to the maximum hardness of coatings or adhesive strength.

Predicting wear of hydrotransport pipelines in oil sand slurries

Energy Technology Data Exchange (ETDEWEB)

Been, J.; Lu, B.; Wolodko, J. [Alberta Research Council, Edmonton, AB (Canada); Kiel, D. [Coanda Research and Development Corp., Burnaby, BC (Canada)

2008-07-01

An overview of erosion and corrosion methods and techniques was presented. Wear to pipelines is influenced by slurry flow and chemistry; solids loading; and electrochemical interactions. While several experimental techniques have been developed to rank the performance of different pipeline materials, experiments do not currently provide accurate quantitative prediction of pipeline wear in the field. Rotating cylinder electrodes (RCE) and jet impingement methods are used to study the effect of flow velocity on corrosion rate. Slurry pot erosion-corrosion testers are used to rank materials for use in more dilute, less turbulent slurries. Coriolois slurry erosion testers are used to rank the erosion resistance of different pipeline materials. A pilot-scale flow loop is now being constructed by the Alberta Research Council (ARC) in order to replicate wet erosion phenomena in oil sands applications. The flow loop will be used to simulate the field conditions of oil sands pipelines and develop predictive wear data and models. Coulombic shear stress and characteristic wall velocities have been determined using a 2-layer model designed to represent flow as 2 distinct layers. To date, the flow loop pilot study has demonstrated that wear rates in smaller diameter flow loops are not significantly different than larger diameter field installations. Preliminary calculations have demonstrated that the flow loop can be used to accurately simulate the hydrodynamics and wear typically experienced in field slurry flows. 67 refs., 2 tabs., 7 figs.

Material irradiation techniques used in corrosion and wear analysis

International Nuclear Information System (INIS)

Tenreiro, Claudio

1996-01-01

Full text: Nuclear physics methods, applied to material analysis are discussed and some application examples are given. Experiments have been performed to study corrosion du to the presence of humidity and sulfur compounds. The use of resonant reactors allows the determination of depth profiles of H and S from structures located in particularly contaminated areas. The method provides a non destructive and quick way of estimating the effect of such elements in different types of structures, such as the ones used in high voltage transmission lines. Also the wear out rates in mechanical engine components having a difficult direct access, have been evaluated by proton activation analysis. The evaluation of the advantages of this method is being done. The effect of irradiation damage on superconducting high temperature ceramics was analyzed by the interaction of energetic alpha particles with high T c YBaCuO samples

Dense nanostructured t-ZrO2 coatings at low temperatures via modified emulsion precipitation

NARCIS (Netherlands)

Woudenberg, F.C.M.; Sager, W.F.C.; Sibelt, N.G.M.; Verweij, H.

2001-01-01

Nanostructured coatings on metals, plastics, and textiles have numerous applications, for example, as antifogging and self-cleaning coatings as well as protective coatings against corrosion, heat, or wear. Here the preparation at low temperature of dense nanostructured tetragonal ZrO2 coatings via a

Wear monitoring of single point cutting tool using acoustic emission ...

Indian Academy of Sciences (India)

feeds are used, the coating remains intact throughout the duration of testing. Wear ... present global industrial scenario is to produce quality products at competitive price. .... Coated carbide tool was selected based on its wider application.

Characterization of wear debris from metal-on-metal hip implants during normal wear versus edge-loading conditions.

Science.gov (United States)

Kovochich, Michael; Fung, Ernest S; Donovan, Ellen; Unice, Kenneth M; Paustenbach, Dennis J; Finley, Brent L

2018-04-01

Advantages of second-generation metal-on-metal (MoM) hip implants include low volumetric wear rates and the release of nanosized wear particles that are chemically inert and readily cleared from local tissue. In some patients, edge loading conditions occur, which result in higher volumetric wear. The objective of this study was to characterize the size, morphology, and chemistry of wear particles released from MoM hip implants during normal (40° angle) and edge-loading (65° angle with microseparation) conditions. The mean primary particle size by volume under normal wear was 35 nm (range: 9-152 nm) compared with 95 nm (range: 6-573 nm) under edge-loading conditions. Hydrodynamic diameter analysis by volume showed that particles from normal wear were in the nano- (edge-loading conditions generated particles that ranged from Edge-loading conditions generated more elongated particles (4.5%) (aspect ratio ≥ 2.5) and more CoCr alloy particles (9.3%) compared with normal wear conditions (1.3% CoCr particles). By total mass, edge-loading particles contained approximately 640-fold more cobalt than normal wear particles. Our findings suggest that high wear conditions are a potential risk factor for adverse local tissue effects in MoM patients who experience edge loading. This study is the first to characterize both the physical and chemical characteristics of MoM wear particles collected under normal and edge-loading conditions. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 986-996, 2018. © 2017 Wiley Periodicals, Inc.

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.

Friction and wear behaviour of hypereutectic Al-Si alloy/steel tribopair under dry and lubricated conditions

Directory of Open Access Journals (Sweden)

Parveen Kumar

2017-12-01

Full Text Available Dry and lubricated sliding tribological tests on hypereutectic Al-25Si alloy was performed using a ball- on- disk configuration at room temperature. Hypereutectic Al-25Si alloy were prepared by rapid solidification process under T6 condition. Friction coefficient (COF and wear rate of the alloy were measured under different applied loads ranging from 5–100 N. It is found that the friction coefficient varies with load, first declines (from 5-50 N, then increases (from 50-80 N and then again decreases (80-100 N. The wear rate of the samples of hypereutectic Al-25Si alloy, first increases and then decreases with increasing the applied normal load. Hypereutectic Al-25Si alloy presents higher wear rate at 50 N due to the participation of a large amount of needle-like precipitates, but shows low wear rate under high load of 100 N because of the work hardening layer. Worn surface morphologies were analyzed using optical and scanning electron microscope (SEM coupled with an energy dispersive spectrometer (EDS. The improvements in COF and wear rate were mainly attributed to morphology, size and distribution of Si particles due to its fabrication process. The dominant wear mechanism for hypereutectic Al-25Si alloy was adhesive wear, abrasive wear and plastic deformation.

The effect of fiber treatment on abrasive wear properties of palm fiber reinforced epoxy composite

Science.gov (United States)

Razak, Muhammad Firdaus Abdul; Bakar, Mimi Azlina Abu; Kasolang, Salmiah; Ahmad, Mohamad Ali

2017-12-01

Oil palm industries generate at least 30 million tons of lignocellulosic biomass annually in the form of oil palm trunks (OPT), empty fruit bunches (EFB), oil palm fronds (OPF) and palm pressed fibres (PPF). The palm fiber is one of the natural fibers used as reinforcement in composite materials in order to decrease environmental issues and promotes utilization of renewable resources. This paper presents a study on the effect of alkaline treatment on wear properties of palm fiber reinforced epoxy resin composite. Abrasive wear testing was deployed to investigate the wear profile of the composite surfaces. Testing was carried out which focused on the effect of alkaline treatment to the palm fiber under different amounts of fiber loading i.e. 1 wt%, 3 wt%, 5 wt% and 7 wt%. The palm fibers were soaked into 6 % of alkaline solution or natrium hydroxide (NaOH) for 12 hours. The fiber was treated in order to remove amorphous materials such as hemicelluloses, lignins and pectins of the fiber. The wear test samples were fabricated using hand lay-up technique and cured at room temperature for 24 hours. Surface roughness of the composite material was also measured using the surface measuring instrument. Dry sliding wear test was performed at room temperature at a constant velocity of 1.4 m/s with a constant load of 10 N by using the Abrasion Test Machine. Result shows that 5 wt% and 7 wt% treated palm fiber loadings have better specific wear rate compared to lower fiber loadings. The finding of this study contributes towards material development and utilization in promoting `waste into wealth' which is in line with national aspiration.

Chameleon Coatings: Adaptive Surfaces to Reduce Friction and Wear in Extreme Environments

Science.gov (United States)

Muratore, C.; Voevodin, A. A.

2009-08-01

Adaptive nanocomposite coating materials that automatically and reversibly adjust their surface composition and morphology via multiple mechanisms are a promising development for the reduction of friction and wear over broad ranges of ambient conditions encountered in aerospace applications, such as cycling of temperature and atmospheric composition. Materials selection for these composites is based on extensive study of interactions occurring between solid lubricants and their surroundings, especially with novel in situ surface characterization techniques used to identify adaptive behavior on size scales ranging from 10-10 to 10-4 m. Recent insights on operative solid-lubricant mechanisms and their dependency upon the ambient environment are reviewed as a basis for a discussion of the state of the art in solid-lubricant materials.

Study on the friction and wear properties of carbon fabric composites reinforced with micro- and nano-particles

International Nuclear Information System (INIS)

Zhang Zhaozhu; Su Fenghua; Wang Kun; Jiang Wei; Men Xuehu; Liu Weimin

2005-01-01

The carbon fabric composites filled with the particulates of polyfluo-150 wax (PFW), nano-particles of ZnO (nano-ZnO), and nano-particles of SiC (nano-SiC), respectively, were prepared by dip-coating of the carbon fabric in a phenolic resin containing the particulates to be incorporated and the successive curing. The friction and wear behaviors of the carbon fabric composites sliding against AISI-1045 steel in a pin-on-disk configuration are evaluated on a Xuanwu-III high-temperature friction and wear tester. The morphologies of the worn surfaces of the filled carbon fabric composites and the counterpart steel pins are analyzed by means of scanning electron microscopy. The effect of the fillers on the adhesion strength of the adhesive is evaluated using a DY35 universal materials tester. It is found that the fillers PFW, nano-ZnO, and nano-SiC contribute to significantly increasing anti-wear abilities of the carbon fabric composites, however, nano-SiC increase the friction coefficient of the carbon fabric composites. The wear rates of the composites at elevated temperature above 180 deg. C are much larger than that below 180 deg. C, which attribute to the degradation and decomposition of the adhesive resin at an excessively elevated temperature. That the interface bonding strength among the carbon fabric, the adhesive, and the particles is significantly increased after solidification and with the transferred film of the varied features largely account for the increased wear-resistance of the filled carbon fabric composites as compared with the unfilled one

Wear of rolling element bearings in sodium

International Nuclear Information System (INIS)

Campbell, C.S.

1976-01-01

Rolling element bearings and related mechanisms are attractive for service in liquid sodium but it is not clear what minimum wear rate can be anticipated. For axially loaded angular contact bearings rotation is incompatible with pure rolling on both races and wear arises from the resulting ball spin. The initial pressure distributions and sizes of the contact ellipses can be calculated but will change with bearing wear. However, the most effective distribution for producing wear would be for the full loads to be borne on the tips of the contact areas, whose maximum length is given by examination of the race wear tracks. A calculation on such a basis should set a lower limit for the wear coefficient. Both the torque and instantaneous wear rate of a bearing will be similar functions of the integral over the contact areas of the product of contact pressure and radius from the ball spin axis. A better estimate of wear coefficient should be obtained by relating the average torque, the average wear, the initial torque and the initial wear where the conditions are known. Analysis of tests in sodium at 400 0 C of high speed steel and Stellite bearings by these methods indicates specific wear rates of the order of 10 -15 m 3 /N-m, not unduly out of line with the range of values found in conventional sliding tests

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.

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

The physiological demands of horseback mustering when wearing an equestrian helmet.

Science.gov (United States)

Taylor, Nigel A S; Caldwell, Joanne N; Dyer, Rodd

2008-09-01

The hottest months on northern Australian cattle stations are from September to November, and it is during these months that horseback cattle mustering occurs. Stockmen wear clothing that restricts heat loss, and protective helmets have recently been introduced. Anecdotal evidence points to the possibility that helmets may increase the probability of developing heat illness, or reducing workplace performance. In this project, we quantified the working (thermal) environment on such cattle stations, and measured the metabolic demands on, and concurrent physiological strain in stockmen during mustering, whilst wearing an equestrian helmet. During horseback work, the average heart rate was 102.0 beats min(-1) (SD 14.0), with almost 90% of the time (238 min) spent working at intensities <50% of the heart rate reserve. The projected metabolic heat production during mustering ranged between 178 and 333 W (women), and between 212 and 542 W (men). The average core temperature was 37.6 degrees C, while the mean skin temperature averaged 34.1 degrees C. It was concluded that the working environment is, on average, thermally uncompensable during the mustering season. However, horseback mustering per se is a relatively low-intensity activity, interspersed with short periods of high-intensity work. This activity level was reflected within core temperatures, which rarely climbed above values associated with light-moderate exercise. Thus, whilst the climatic state was uncompensable, stockmen used behavioural strategies to minimise the risk of heat illness. Finally, it was observed that the helmet, though unpleasant to wear, did not appear to increase thermal strain in a manner that would disadvantage stockmen.

Wear mechanisms of toughened zirconias

International Nuclear Information System (INIS)

Becker, P.C.; Libsch, T.A.; Rhee, S.K.

1985-01-01

The dry friction and wear behavior of toughened zirconias against hardened steel was studied using the falex ring and block technique. Three experimental ZrO 2 -Y 2 O 3 ceramics and two commerical ZrO 2 -MgO ceramics were investigated. Each ceramic was tested at 500 and 2000 rpm at normal loads in the range 2.3 to 40.8 kg. Significant trends in the friction and wear data were found correlating composition, test speeds, and loads. Microstructural examination of the ring, ceramic block, and wear debris has shown that the wear process is very complex and incorporates a number of mechanisms

High-Temperature Tensile and Tribological Behavior of Hybrid (ZrB2+Al3Zr)/AA5052 In Situ Composite

Science.gov (United States)

Gautam, G.; Kumar, N.; Mohan, A.; Gautam, R. K.; Mohan, S.

2016-09-01

During service life, components such as piston, cylinder blocks, brakes, and discs/drums, have to work under high-temperature conditions. In order to have appropriate material for such applications high-temperature studies are important. Hybrid (ZrB2+Al3Zr)/AA5052 in situ composite has been investigated from ambient to 523 K (250 °C) at an interval of 50 deg. (ZrB2+Al3Zr)/AA5052 in situ composite has been fabricated by the direct melt reaction of AA5052 alloy with zirconium and boron salts. Microstructure studies show refinement in the grain size of base alloy on in situ formation of reinforcement particles. Al3Zr particles are observed in rectangular and polyhedron shapes. It is observed from the tensile studies that ultimate tensile strength, yield strength, and percentage elongation decrease with increase in test temperature. Similar kind of behavior is also observed for flow curve properties. The tensile results have also been correlated with fractography. Wear and friction results indicate that the wear rate increases with increase in normal load, whereas coefficient of friction shows decreasing trend. With increasing test temperature, wear rate exhibits a typical phenomenon. After an initial increase, wear rate follows a decreasing trend up to 423 K (150 °C), and finally a rapid increase is observed, whereas coefficient of friction increases continuously with increase in test temperature. The mechanisms responsible for the variation of wear and friction with different temperatures have been discussed in detail with the help of worn surfaces studies under scanning electron microscope (SEM) & 3D-profilometer and debris analysis by XRD.

Brush Seals for Cryogenic Applications: Performance, Stage Effects, and Preliminary Wear Results in LN2 and LH2

Science.gov (United States)

Proctor, Margaret P.; Walker, James F.; Perkins, H. Douglas; Hoopes, Joan F.; Williamson, G. Scott

1996-01-01

Brush seals are compliant contacting seals and have significantly lower leakage than labyrinth seals in gas turbine applications. Their long life and low leakage make them candidates for use in rocket engine turbopumps. Brush seals, 50.8 mm (2 in.) in diameter with a nominal 127-micron (0.005-in.) radial interference, were tested in liquid nitrogen (LN2) and liquid hydrogen (LH2) at shaft speeds up to 35,000 and 65,000 rpm, respectively, and at pressure drops up to 1.21 MPa (175 psid) per brush. A labyrinth seal was also tested in liquid nitrogen to provide a baseline. The LN2 leakage rate of a single brush seal with an initial radial shaft interference of 127 micron (0.005 in.) measured one-half to one-third the leakage rate of a 12-tooth labyrinth seal with a radial clearance of 127 micron (0.005 in.). Two brushes spaced 7.21 micron (0.248 in.) apart leaked about one-half as much as a single brush, and two brushes tightly packed together leaked about three-fourths as much as a single brush. The maximum measured groove depth on the Inconel 718 rotor with a surface finish of 0.81 micron (32 microinch) was 25 micron (0.0010 in.) after 4.3 hr of shaft rotation in liquid nitrogen. The Haynes-25 bristles wore approximately 25 to 76 micron (0.001 to 0.003 in.) under the same conditions. Wear results in liquid hydrogen were significantly different. In liquid hydrogen the rotor did not wear, but the bristle material transferred onto the rotor and the initial 127 micron (0.005 in.) radial interference was consumed. Relatively high leakage rates were measured in liquid hydrogen. More testing is required to verify the leakage performance, to validate and calibrate analysis techniques, and to determine the wear mechanisms. Performance, staging effects, and preliminary wear results are presented.

Fluoridation and tooth wear in Irish adults.

LENUS (Irish Health Repository)

Burke, F M

2010-10-01

The aim of this study was to determine the prevalence of tooth wear in adults in Ireland and its relationship with water fluoridation. The National Survey of Adult Oral Health was conducted in 2000\\/2001. Tooth wear was determined using a partial mouth examination assessing the upper and lower anterior teeth. A total of 2456 subjects were examined. In this survey, increasing levels and severity of tooth wear were associated with ageing. Men were more affected by tooth wear and were more likely to be affected by severe tooth wear than women. It was found that age, and gender were significant predictors of tooth wear (P < 0.01). Overall, there was no significant relationship between fluoridation and tooth wear in this study.

Backside wear in modern total knee designs.

Science.gov (United States)

Jayabalan, Prakash; Furman, Bridgette D; Cottrell, Jocelyn M; Wright, Timothy M

2007-02-01

Although modularity affords various options to the orthopedic surgeon, these benefits come at a price. The unintended bearing surface between the back surface of the tibial insert and the metallic tray results in micromotion leading to polyethylene wear debris. The objective of this study was to examine the backside wear of tibial inserts from three modern total knee designs with very different locking mechanisms: Insall-Burstein II (IB II), Optetrak, and Advance. A random sample of 71 inserts were obtained from our institution's retrieval collection and examined to assess the extent of wear, depth of wear, and wear damage modes. Patient records were also obtained to determine patient age, body mass index, length of implantation, and reason for revision. Modes of wear damage (abrasion, burnishing, scratching, delamination, third body debris, surface deformation, and pitting) were then scored in each zone from 0 to 3 (0 = 0%, 1 = 0-10%, 2 = 10-50%, and 3 = >50%). The depth of wear was subjectively identified as removal of manufacturing identification markings stamped onto the inferior surface of the polyethylene. Both Advance and IB II polyethylene inserts showed significantly higher scores for backside wear than the Optetrak inserts. All IB II and Advance implants showed evidence of backside wear, whereas 17% (5 out of 30) of the retrieved Optetrak implants had no observable wear. There were no significant differences when comparing the depth of wear score between designs. The locking mechanism greatly affects the propensity for wear and should be considered when choosing a knee implant system.

Wear mechanisms and friction parameters for sliding wear of micron-scale polysilicon sidewalls

NARCIS (Netherlands)

Alsem, D. H.; van der Hulst, R.; Stach, E. A.; Dugger, M. T.; De Hosson, J. Th. M.; Ritchie, R. O.

As tribological properties are critical factors in the reliability of silicon-based microelectromechanical systems, it is important to understand what governs wear and friction. Average dynamic friction, wear volumes and morphology have been studied for polysilicon devices fabricated using the

Effect of surface oxidation on the nm-scale wear behavior of a metallic glass

International Nuclear Information System (INIS)

Caron, A.; Louzguine-Luzguin, D. V.; Sharma, P.; Inoue, A.; Shluger, A.; Fecht, H.-J.

2011-01-01

Metallic glasses are good candidates for applications in micromechanical systems. With size reduction of mechanical components into the micrometer and submicrometer range, the native surface oxide layer starts playing an important role in contact mechanical applications of metallic glasses. We use atomic force microscopy to investigate the wear behavior of the Ni 62 Nb 38 metallic glass with a native oxide layer and with an oxide grown after annealing in air. After the annealing, the wear rate is found to have significantly decreased. Also the dependency of the specific wear on the velocity is found to be linear in the case of the as spun sample while it follows a power law in the case of the sample annealed in air. We discuss these results in relation to the friction behavior and properties of the surface oxide layer obtained on the same alloy.

Exploring new W–B coating materials for the aqueous corrosion–wear protection of austenitic stainless steel

Energy Technology Data Exchange (ETDEWEB)

Mallia, B., E-mail: bertram.mallia@um.edu.mt [Department of Metallurgy and Materials Engineering, University of Malta, Msida MSD 2080 (Malta); Dearnley, P.A. [nCATS National Centre for Advanced Tribology Southampton, Engineering Sciences, University of Southampton, Southampton SO17 1BJ (United Kingdom)

2013-12-31

The material loss of metallic surfaces through corrosion–wear is a serious concern in many application sectors, ranging from bio-medical implants to marine, oil and gas field components to transport vehicle and nuclear reactor devices. In principle, self-passivating alloys, like stainless steels, can be protected from surface degradation caused by corrosion–wear through the application of protective thin, hard surface coatings. In this work the suitability of using W matrix coating materials supersaturated with varying levels of boron were applied to austenitic stainless steel substrates (Ortron 90) and assessed for this purpose. These materials were compared to a highly corrosion–wear resistant “datum” surface engineered material (CrN coated Ti–6Al–4V) in sliding contact tests against a chemically inert aluminium oxide ball, whilst immersed in 0.9% NaCl solution at 37 °C. The work demonstrated that all the coated materials to be very much more resistant to material loss through corrosion–wear (by nearly an order of magnitude) compared to uncoated stainless steel, and two coatings, W–13%B and W–23%B coated Ortron 90 were similarly resistant as CrN coated Ti–6Al–4V. Three fundamental types of corrosion–wear were discovered that represented differing levels of passive film durability. The total material loss rate (TMLR) during corrosion–wear testing showed linear proportionality with the change in open circuit potential δ{sub OCP} which obeyed the governing equation: TMLR = m δ{sub OCP} + C. - Highlights: • Magnetron sputtered W–(B) coatings displayed a crystalline to amorphous transition. • W–(B) coatings displayed excellent corrosion–wear resistance under OCP conditions. • Three kinds of corrosion–wear behaviour were determined in this study. • A linear correlation between total material loss and change in OCP was discovered. • Static CV tests were not useful for predicting dynamic corrosion–wear behaviour.

Microstructure and wear resistance of a laser clad TiC reinforced nickel aluminides matrix composite coating

International Nuclear Information System (INIS)

Chen, Y.; Wang, H.M.

2004-01-01

Wear resistant TiC/(NiAl-Ni 3 Al) composite coating was fabricated on a substrate of electrolyzed nickel by laser cladding using Ni-Al-Ti-C alloy powders. The laser clad coating is metallurgically bonded to the substrate and has a homogenous fine microstructure consisting of the flower-like equiaxed TiC dendrite and the dual phase matrix of NiAl and Ni 3 Al. The intermetallic matrix composite coating exhibits excellent wear resistance under both room- and high-temperature sliding wear test conditions due to the high hardness of TiC coupled with the strong atomic bonds of intermetallic matrix

APPRAISAL OF APPLICATION OF WEAR-RESISTANT CHROMIC CAST IRONS FOR PRODUCTION OF MOULDED PIECES OF EQUIPMENT ON PRODUCTION OF BRICK OF CLAY

Directory of Open Access Journals (Sweden)

K. E. aranovkij

2007-01-01

Full Text Available The appraisal of application of wear-resistant chromic cast irons of different chemical compositions for production of moulded pieces of equipment on production of bricks of clay is carried out. It is determined that working resource of the details of test cast-irons is correlated with their hardness and not lower than of hardened steel.

Friction and wear behaviour of Mo–W doped carbon-based coating during boundary lubricated sliding

Energy Technology Data Exchange (ETDEWEB)

Hovsepian, Papken Eh., E-mail: p.hovsepian@shu.ac.uk [Nanotechnology Centre for PVD Research, HIPIMS Research Centre, Sheffield Hallam University, City Campus, Howard Street, Sheffield S1 1WB (United Kingdom); Mandal, Paranjayee, E-mail: 200712mum@gmail.com [Nanotechnology Centre for PVD Research, HIPIMS Research Centre, Sheffield Hallam University, City Campus, Howard Street, Sheffield S1 1WB (United Kingdom); Ehiasarian, Arutiun P., E-mail: a.ehiasarian@shu.ac.uk [Nanotechnology Centre for PVD Research, HIPIMS Research Centre, Sheffield Hallam University, City Campus, Howard Street, Sheffield S1 1WB (United Kingdom); Sáfrán, G., E-mail: safran.gyorgy@ttk.mta.hu [Institute for Technical Physics and Materials Science, Centre for Energy Research, Hungarian Academy of Sciences, H-1121 Budapest, Konkoly-Thegeut 29-33 (Hungary); Tietema, R., E-mail: rtietema@hauzer.nl [IHI Hauzer Techno Coating B.V., Van Heemskerckweg 22, 5928 LL Venlo (Netherlands); Doerwald, D., E-mail: ddoerwald@hauzer.nl [IHI Hauzer Techno Coating B.V., Van Heemskerckweg 22, 5928 LL Venlo (Netherlands)

2016-03-15

Graphical abstract: - Highlights: • Novel Mo–W–C coating provides extremely low friction (μ ∼ 0.03) in lubricated condition. • Mo–W–C outperforms existing DLCs in terms of low friction, independent of temperature. • Tribochemical reactions govern the wear mechanism of Mo–W–C coating. • The transfer layer contains graphitic carbon and ‘in situ’ formed WS{sub 2} and MoS{sub 2}. • WS{sub 2} and MoS{sub 2} are the key factors facilitating appreciably low friction and wear rate. - Abstract: A molybdenum and tungsten doped carbon-based coating (Mo–W–C) was developed in order to provide low friction in boundary lubricated sliding condition at ambient and at high temperature. The Mo–W–C coating showed the lowest friction coefficient among a number of commercially available state-of-the-art DLC coatings at ambient temperature. At elevated temperature (200 °C), Mo–W–C coating showed a significant reduction in friction coefficient with sliding distance in contrast to DLC coatings. Raman spectroscopy revealed the importance of combined Mo and W doping for achieving low friction at both ambient and high temperature. The significant decrease in friction and wear rate was attributed to the presence of graphitic carbon debris (from coating) and ‘in situ’ formed metal sulphides (WS{sub 2} and MoS{sub 2}, where metals were supplied from coating and sulphur from engine oil) in the transfer layer.

Friction and wear behaviour of Mo–W doped carbon-based coating during boundary lubricated sliding

International Nuclear Information System (INIS)

Hovsepian, Papken Eh.; Mandal, Paranjayee; Ehiasarian, Arutiun P.; Sáfrán, G.; Tietema, R.; Doerwald, D.

2016-01-01

Graphical abstract: - Highlights: • Novel Mo–W–C coating provides extremely low friction (μ ∼ 0.03) in lubricated condition. • Mo–W–C outperforms existing DLCs in terms of low friction, independent of temperature. • Tribochemical reactions govern the wear mechanism of Mo–W–C coating. • The transfer layer contains graphitic carbon and ‘in situ’ formed WS 2 and MoS 2 . • WS 2 and MoS 2 are the key factors facilitating appreciably low friction and wear rate. - Abstract: A molybdenum and tungsten doped carbon-based coating (Mo–W–C) was developed in order to provide low friction in boundary lubricated sliding condition at ambient and at high temperature. The Mo–W–C coating showed the lowest friction coefficient among a number of commercially available state-of-the-art DLC coatings at ambient temperature. At elevated temperature (200 °C), Mo–W–C coating showed a significant reduction in friction coefficient with sliding distance in contrast to DLC coatings. Raman spectroscopy revealed the importance of combined Mo and W doping for achieving low friction at both ambient and high temperature. The significant decrease in friction and wear rate was attributed to the presence of graphitic carbon debris (from coating) and ‘in situ’ formed metal sulphides (WS 2 and MoS 2 , where metals were supplied from coating and sulphur from engine oil) in the transfer layer.

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.

Decontamination of radioactive contaminated protective wear using dry cleaning solvent

International Nuclear Information System (INIS)

Muthiah, Pushpa; Chitra, S.; Paul, Biplob

2013-01-01

Liquid waste generated by conventional decontamination of radioactive contaminated cotton protective wear using detergent affects the chemical treatment of the plant. To reduce the generation of aqueous detergent waste, dry cleaning of cotton protective wear, highly soiled with oil and grease towards decontamination was tried with organic solvents. Mineral turpentine oil (MTO) among various other organic solvents was identified as a suitable organic solvent. As MTO leaves characteristic odour on the cloth, various commercial fragrances for the removal of the odour were tried. Application of the optimised dry cleaning solvent and commercial fragrance was adopted in plant scale operation. (author)

Modeling wear of cast Ti alloys.

Science.gov (United States)

Chan, Kwai S; Koike, Marie; Okabe, Toru

2007-05-01

The wear behavior of Ti-based alloys was analyzed by considering the elastic-plastic fracture of individual alloys in response to the relevant contact stress field. Using the contact stresses as the process driving force, wear was computed as the wear rate or volume loss as a function of hardness and tensile ductility for Ti-based cast alloys containing an alpha, alpha+beta or beta microstructure with or without the intermetallic precipitates. Model predictions indicated that wear of Ti alloys increases with increasing hardness but with decreasing fracture toughness or tensile ductility. The theoretical results are compared with experimental data to elucidate the roles of microstructure in wear and contrasted against those in grindability.

An in vitro study of dental enamel wear by restorative materials using radiometric method

International Nuclear Information System (INIS)

Adachi, Lena Katekawa

2000-01-01

There is an increasing demand and interest to study the dental materials wear as well as about the abrasion effect on antagonistic teeth. Due to the fact that the existent restorative materials have no specifications about their abrasiveness, it is necessary the establishment of degrees of comparison among them to support clinical application. In this work, the radiometric method was applied to study the enamel wear caused by another enamel and by restorative materials (Ceramco II, Noritake and Finesse porcelains, Artglass and Targis). The dental enamel made radioactive by irradiation at the IEA-R1m nuclear research reactor under a thermal neutron flux was submitted to wear in a machine which allows sliding motion of an antagonistic surface in contact with this radioactive enamel. The enamel wear was evaluated by measuring beta activity of 32 P transferred to water from this irradiated tooth. Results obtained indicated that dental porcelains cause pronounced enamel wear when compared with that provoked by another enamel or by resin materials. Resin materials caused less enamel wear than another enamel. Vickers microhardness data obtained for antagonistic materials showed a correlation with the wear caused to the enamel. This study allowed to conclude that the radiometric method proposed can be used satisfactorily in the evaluation of enamel wear by restorative materials. This method presents advantages due to quick responses and ease of analyses There is (author)

Friction and wear performance of low-friction carbon coatings under oil lubrication

International Nuclear Information System (INIS)

Kovalchenko, A.; Ajayi, O. O.; Erdemir, A.; Fenske, G. R.

2001-01-01

Amorphous carbon coatings with very low friction properties were recently developed at Argonne National Laboratory. These coatings have shown good promise in mitigating excessive wear and scuffing problems associated with low-lubricity diesel fuels. To reduce the negative effect of sulfur and other lubricant additives in poisoning the after-treatment catalyst, a lubricant formulation with a low level of sulfur may be needed. Exclusion of proven sulfur-containing extreme pressure (EP) and antiwear additives from oils will require other measures to ensure durability of critical lubricated components. The low-friction carbon coating has the potential for such applications. In the present study, we evaluated the friction and wear attributes of three variations of the coating under a boundary lubrication regime. Tests were conducted with both synthetic and mineral oil lubricants using a ball-on-flat contact configuration in reciprocating sliding. Although the three variations of the coating provided modest reductions in friction coefficient, they all reduced wear substantially compared to an uncoated surface. The degradation mode of oxidative wear on the uncoated surface was replaced by a polishing wear mode on the coated surfaces

Optical wear monitoring

Science.gov (United States)

Kidane, Getnet S; Desilva, Upul P.; He, Chengli; Ulerich, Nancy H.

2016-07-26

A gas turbine includes first and second parts having outer surfaces located adjacent to each other to create an interface where wear occurs. A wear probe is provided for monitoring wear of the outer surface of the first part, and includes an optical guide having first and second ends, wherein the first end is configured to be located flush with the outer surface of the first part. A fiber bundle includes first and second ends, the first end being located proximate to the second end of the optical guide. The fiber bundle includes a transmit fiber bundle comprising a first plurality of optical fibers coupled to a light source, and a receive fiber bundle coupled to a light detector and configured to detect reflected light. A processor is configured to determine a length of the optical guide based on the detected reflected light.

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.

Plasma nitrocarburizing process - a solution to improve wear and corrosion resistance

International Nuclear Information System (INIS)

Joseph, Alphonsa J.; Ghanshyam, J.; Mukherjee, S.

2015-01-01

To prevent wear and corrosion problems in steam turbines, coatings have proved to have an advantage of isolating the component substrate from the corrosive environment with minimal changes in turbine material and design. Diffusion based coatings like plasma nitriding and plasma nitrocarburizing have been used for improving the wear and corrosion resistance of components undergoing wear during their operation. In this study plasma nitrocarburizing process was carried out on ferritic alloys like ASTM A182 Grade F22 and ATM A105 alloy steels and austenitic stainless steels like AISI 304 and AISI 316 which are used to make trim parts of control valves used for high pressure and high temperature steam lines to enhance their wear and corrosion resistance properties. The corrosion rate was measured by a potentiodynamic set up and salt spray unit in two different environments viz., tap water and 5% NaCl solutions. The Tafel plots of ferritic alloys and austenitic stainless steels show that plasma nitrocarburizing process show better corrosion resistance compared to that of the untreated steel. It was found that after plasma nitrocarburizing process the hardness of the alloy steels increased by a factor of two. The corrosion resistance of all the steels mentioned above improved in comparison to the untreated steels. This improvement can be attributed to the nitrogen and carbon incorporation in the surface of the material. This process can be also applied to components used in nuclear industries to cater to the wear and corrosion problems. (author)

Wear of cross-linked polyethylene against itself: a material suitable for surface replacement of the finger joint.

Science.gov (United States)

Sibly, T F; Unsworth, A

1991-05-01

Cross-linking of polyethylene (XLPE) has dramatically improved its properties in industrial applications, and it may also have some application in the field of human joint replacement. Additionally it has the advantage of permitting a lower molecular weight base material to be used, so that components may be injection moulded rather than machined. This study therefore investigates the wear resistance of medical grade cross-linked polyethylene (XLPE), cross-linked by a silane-grafting process, with a molecular weight between cross links of 5430 g mol(-1). This first report investigates the wear resistance of XLPE against itself, because for certain joints, such as the metacarpo-phalangeal joint, the material may have a high enough wear resistance to allow both bearing surfaces to be made from it. Tests were carried out both on a reciprocating pin and plate machine with pins loaded at 10 and 40 N and also on a new finger joint simulator, which simulates the loads applied to and the movements of, the metacarpo-phalangeal joint. An average wear rate of 1.8 x 10(-6) mm3 N-1 m-1 was found (range 0.9-2.75 x 10(-6) mm3 N-1 m-1). This is about six times greater than the wear rate of non-cross-linked ultra high molecular weight polyethylene (UHMWPE) against stainless steel, but for applications with low loading, such as the metacarpo-phalangeal joint, this material is shown to have adequate wear resistance. The coefficient of friction was 0.1, which is similar to that of UHMWPE on stainless steel.

Microstructural and Wear Behavior Characterization of Porous Layers Produced by Pulsed Laser Irradiation in Glass-Ceramics Substrates.

Science.gov (United States)

Sola, Daniel; Conde, Ana; García, Iñaki; Gracia-Escosa, Elena; de Damborenea, Juan J; Peña, Jose I

2013-09-09

In this work, wear behavior and microstructural characterization of porous layers produced in glass-ceramic substrates by pulsed laser irradiation in the nanosecond range are studied under unidirectional sliding conditions against AISI316 and corundum counterbodies. Depending on the optical configuration of the laser beam and on the working parameters, the local temperature and pressure applied over the interaction zone can generate a porous glass-ceramic layer. Material transference from the ball to the porous glass-ceramic layer was observed in the wear tests carried out against the AISI316 ball counterface whereas, in the case of the corundum ball, the wear volume loss was concentrated in the porous layer. Wear rate and friction coefficient presented higher values than expected for dense glass-ceramics.

Microstructural and Wear Behavior Characterization of Porous Layers Produced by Pulsed Laser Irradiation in Glass-Ceramics Substrates

Directory of Open Access Journals (Sweden)

Jose I. Peña

2013-09-01

Full Text Available In this work, wear behavior and microstructural characterization of porous layers produced in glass-ceramic substrates by pulsed laser irradiation in the nanosecond range are studied under unidirectional sliding conditions against AISI316 and corundum counterbodies. Depending on the optical configuration of the laser beam and on the working parameters, the local temperature and pressure applied over the interaction zone can generate a porous glass-ceramic layer. Material transference from the ball to the porous glass-ceramic layer was observed in the wear tests carried out against the AISI316 ball counterface whereas, in the case of the corundum ball, the wear volume loss was concentrated in the porous layer. Wear rate and friction coefficient presented higher values than expected for dense glass-ceramics.

A rolling-gliding wear simulator for the investigation of tribological material pairings for application in total knee arthroplasty

OpenAIRE

Richter, Berna I; Ostermeier, Sven; Turger, Anke; Denkena, Berend; Hurschler, Christof

2010-01-01

Abstract Background Material wear testing is an important technique in the development and evaluation of materials for use in implant for total knee arthroplasty. Since a knee joint induces a complex rolling-gliding movement, standardised material wear testing devices such as Pin-on-Disc or Ring-on-Disc testers are suitable to only a limited extent because they generate pure gliding motion only. Methods A rolling-gliding wear simulator was thus designed, constructed and implemented, which sim...

Tribological Performance of Duplex-Annealed Ti-6Al-2Sn-4Zr-2Mo Titanium Alloy at Elevated Temperatures Under Dry Sliding Condition

Science.gov (United States)

Heilig, Sebastian; Ramezani, Maziar; Neitzert, Thomas; Liewald, Mathias

2018-03-01

Ti-6Al-2Sn-4Zr-2Mo (Ti-6-2-4-2) is a typical near-α titanium alloy developed for high-temperature applications. It offers numerous enhanced properties like an outstanding strength-to-weight ratio, a low Young's modulus and exceptional creep and corrosion resistance. On the other hand, titanium alloys are known for their weak resistance to wear. Ti-6-2-4-2 is mainly applied in aero engine component parts, which are exposed to temperatures up to 565 °C. Through an increasing demand on efficiency, engine components are exposed to higher combustion pressures and temperatures. Elevated temperature tribology tests were conducted on a pin-on-disk tribometer equipped with a heating chamber. The tests were carried out under dry conditions with a constant sliding distance of 600 m with a speed of 0.16 m/s at the ball point. The sliding partner was AISI E52100 steel ball with the hardness of 58HRC. The varied input variables are normal load and temperature. It can be concluded that the coefficient of friction (CoF) increases with increasing temperature, while the wear rate decreases to its minimum at 600 °C due to increasing adhesion and oxidation mechanisms. Wear track observations using a scanning electron microscope (SEM) including energy-dispersive x-ray spectroscopy (EDS) were used to determine the occurring wear mechanisms.

Statistical models for expert judgement and wear prediction

International Nuclear Information System (INIS)

Pulkkinen, U.

1994-01-01

This thesis studies the statistical analysis of expert judgements and prediction of wear. The point of view adopted is the one of information theory and Bayesian statistics. A general Bayesian framework for analyzing both the expert judgements and wear prediction is presented. Information theoretic interpretations are given for some averaging techniques used in the determination of consensus distributions. Further, information theoretic models are compared with a Bayesian model. The general Bayesian framework is then applied in analyzing expert judgements based on ordinal comparisons. In this context, the value of information lost in the ordinal comparison process is analyzed by applying decision theoretic concepts. As a generalization of the Bayesian framework, stochastic filtering models for wear prediction are formulated. These models utilize the information from condition monitoring measurements in updating the residual life distribution of mechanical components. Finally, the application of stochastic control models in optimizing operational strategies for inspected components are studied. Monte-Carlo simulation methods, such as the Gibbs sampler and the stochastic quasi-gradient method, are applied in the determination of posterior distributions and in the solution of stochastic optimization problems. (orig.) (57 refs., 7 figs., 1 tab.)

Occlusal wear of provisional implant-supported restorations.

Science.gov (United States)

Santing, Hendrik J; Kleverlaan, Cornelis J; Werner, Arie; Feilzer, Albert J; Raghoebar, Gerry M; Meijer, Henny J A

2015-02-01

Implant-supported provisional restorations should be resistant to occlusal wear. 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 methacrylate-based materials used to fabricate provisional implant-supported restorations. The materials were handled and cured according to the manufacturers' instructions. The three-body wear was measured 1 day, 3 days, 7 days, 4 weeks, and 8 weeks after curing using the ACTA wear device. Wear rate decreased significantly after 8 weeks compared with the first day for all tested materials, except for Estenia C&B. The three-body wear of two indirect laboratory composite resins, that is, Estenia C&B and Solidex, was significantly less compared with all other tested materials used for fabricating provisional implant-supported restorations. Of the chair side materials, the wear rate of Protemp Crown Paste was significantly less compared with the others materials used to fabricate chair side provisional implant-supported restorations. The methacrylate-based materials, Temdent Classic and Trim, showed extreme high wear rates. Based on the results of this laboratory study on long-term wear, the use of indirect composite resin is preferred over chair side methacrylate-based materials when the provisional implant-supported restoration has to be in service for a long period of time. Of the investigated materials, only Estenia C&B and Solidex showed wear rate comparable with posterior resin composites. © 2013 Wiley Periodicals, Inc.

How patient-selected colors for removable appliances are reflected in electronically tracked compliance (wear times and wear behavior).

Science.gov (United States)

Schott, Timm C; Menne, Dieter

2018-03-27

A broad spectrum of colors for removable appliances, intended to optimize acceptance of treatment and patient cooperation, have been available on the dental market for years. This is the first study to analyze how patient-selected colors are reflected in wear times and wear behavior of removable appliances. The study included 117 children (55 girls and 62 boys) who were treated with active removable plate or functional appliances. All patients were offered to choose from 11 different colors, which were pooled into six groups (black, blue, green, yellow, pink, red) for analysis, or to combine any two to four colors ("multicolored" group) for their appliances. All appliances featured a built-in microsensor (TheraMon; MC Technology, Hargelsberg, Austria) for objective wear-time tracking. Differences between wear times were analyzed using pairwise t tests and Tukey correction. The longest median wear times were recorded in the blue and green groups (≈11 h/d) and the shortest ones in the red and pink groups (≈9 h/d), but they were not significantly influenced by the patient-selected colors. The median wear times involved an age-related decrease by 0.56 h/y that was statistically significant ( P = .00005). No gender-specific patterns of wear behavior were observed. Patient-selected colors for removable appliances can presumably improve acceptance of treatment, but they are not associated with statistically significant improvements in wear time or wear behavior.

Coupling mechanism between wear and oxidation processes of 304 stainless steel in hydrogen peroxide environments.

Science.gov (United States)

Dong, Conglin; Yuan, Chengqing; Bai, Xiuqin; Li, Jian; Qin, Honglin; Yan, Xinping

2017-05-24

Stainless steel is widely used in strongly oxidizing hydrogen peroxide (H 2 O 2 ) environments. It is crucial to study its wear behaviour and failure mode. The tribological properties and oxidation of 304 stainless steel were investigated using a MMW-1 tribo-tester with a three-electrode setup in H 2 O 2 solutions with different concentrations. Corrosion current densities (CCDs), coefficients of frictions (COFs), wear mass losses, wear surface topographies, and metal oxide films were analysed and compared. The results show that the wear process and oxidation process interacted significantly with each other. Increasing the concentration of H 2 O 2 or the oxidation time was useful to form a layer of integrated, homogeneous, compact and thick metal oxide film. The dense metal oxide films with higher mechanical strengths improved the wear process and also reduced the oxidation reaction. The wear process removed the metal oxide films to increase the oxidation reaction. Theoretical data is provided for the rational design and application of friction pairs in oxidation corrosion conditions.

Atomistic study of ternary oxides as high-temperature solid lubricants

Science.gov (United States)

Gao, Hongyu

Friction and wear are important tribological phenomena tightly associated with the performance of tribological components/systems such as bearings and cutting machines. In the process of contact and sliding, friction and wear lead to energy loss, and high friction and wear typically result in shortened service lifetime. To reduce friction and wear, solid lubricants are generally used under conditions where traditional liquid lubricants cannot be applied. However, it is challenging to maintain the functionality of those materials when the working environment becomes severe. For instance, at elevated temperatures (i.e., above 400 °C), most traditional solid lubricants, such as MoS2 and graphite, will easily oxidize or lose lubricity due to irreversible chemical changes. For such conditions, it is necessary to identify materials that can remain thermally stable as well as lubricious over a wide range of temperatures. Among the currently available high-temperature solid lubricants, Ag-based ternary metal oxides have recently drawn attention due to their low friction and ability to resist oxidation. A recent experimental study showed that the Ag-Ta-O ternary exhibited an extremely low coefficient of friction (0.06) at 750 °C. To fully uncover the lubricious nature of this material as a high-temperature solid lubricant, a series of tribological investigations were carried out based on one promising candidate - silver tantalate (AgTaO3). The study was then extended to alternative materials, Cu-Ta-O ternaries, to accommodate a variety of application requirements. We aimed to understand, at an atomic level, the effects of physical and chemical properties on the thermal, mechanical and tribological behavior of these materials at high temperatures. Furthermore, we investigated potassium chloride films on a clean iron surface as a representative boundary lubricating system in a nonextreme environment. This investigation complemented the study of Ag/Cu-Ta-O and enhanced the

The model of the dependence of the abrasive wear value on the maximal linear wear

Directory of Open Access Journals (Sweden)

О.А. Вишневський

2004-01-01

Full Text Available  The relation of the contact area of the rubber roll with a sample and the maximal linear wear value is found. The mathematical model of the dependence of the wear volume weight value on the maximal dimple depth is presented with the friction on abrasive particles fixed nonrigidly. The relation of volume weight wear with the rubber roll contact surface area with a sample with the friction on abrasive particles fixed nonrigidly is established.

Comparative study of the friction and wear behavior of plasma sprayed conventional and nanostructured WC-12%Co coatings on stainless steel

International Nuclear Information System (INIS)

Zhao Xiaoqin; Zhou Huidi; Chen Jianmin

2006-01-01

Conventional and nanostructured WC-12%Co coatings were deposited on 1Cr18Ni9Ti stainless steel substrate using air plasma spraying. The hardness of the coatings was measured, while their friction and wear behavior sliding against Si 3 N 4 at room temperature and elevated temperatures up to 400 deg. C was comparatively studied. The microstructures and worn surface morphologies of the coatings were comparatively analyzed as well by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDXA). It was found that the as-sprayed WC-12%Co coatings were composed of WC as the major phase and W 2 C, WC 1-x , and W 3 Co 3 C as the minor phases. The plasma sprayed nanostructured WC-12%Co coating had much higher hardness and refined microstructures than the conventional WC-12%Co coating. This largely accounted for the better wear resistance of the nanostructured WC-12%Co coating than the conventional coating. Besides, the two types of WC-12%Co coatings showed minor differences in friction coefficients, though the nanostructured WC-12%Co coating roughly had slightly smaller friction coefficient than the conventional coating under the same sliding condition. Moreover, both the conventional and nanostructured WC-12%Co coatings recorded gradually increased wear rate with increasing temperature, and the nanostructured coating was less sensitive to the temperature rise in terms of the wear resistance. The worn surfaces of the conventional WC-12%Co coating at different sliding conditions showed more severe adhesion, microfracture, and peeling as compared to the nanostructured WC-12%Co coating, which well conformed to the corresponding wear resistance of the two types of coatings. The nanostructured WC-12%Co coating with a wear rate as small as 1.01 x 10 -7 mm 3 /Nm at 400 deg. C could be promising candidate coating for the surface-modification of some sliding components subject to harsh working conditions involving elevated

New methodology for fast prediction of wheel wear evolution

Science.gov (United States)

Apezetxea, I. S.; Perez, X.; Casanueva, C.; Alonso, A.

2017-07-01

In railway applications wear prediction in the wheel-rail interface is a fundamental matter in order to study problems such as wheel lifespan and the evolution of vehicle dynamic characteristic with time. However, one of the principal drawbacks of the existing methodologies for calculating the wear evolution is the computational cost. This paper proposes a new wear prediction methodology with a reduced computational cost. This methodology is based on two main steps: the first one is the substitution of the calculations over the whole network by the calculation of the contact conditions in certain characteristic point from whose result the wheel wear evolution can be inferred. The second one is the substitution of the dynamic calculation (time integration calculations) by the quasi-static calculation (the solution of the quasi-static situation of a vehicle at a certain point which is the same that neglecting the acceleration terms in the dynamic equations). These simplifications allow a significant reduction of computational cost to be obtained while maintaining an acceptable level of accuracy (error order of 5-10%). Several case studies are analysed along the paper with the objective of assessing the proposed methodology. The results obtained in the case studies allow concluding that the proposed methodology is valid for an arbitrary vehicle running through an arbitrary track layout.

The fabrication, nano/micro-structure, heat- and wear-resistance of the superhydrophobic PPS/PTFE composite coatings.

Science.gov (United States)

Wang, Huaiyuan; Zhao, Jingyan; Zhu, Youzhuang; Meng, Yang; Zhu, Yanji

2013-07-15

A simple engineering method was used to fabricate stability and wear-resistance of superhydrophobic PPS-based PPS/PTFE surfaces through nano/micro-structure design and modification of the lowest surface energy groups (-CF2-), which was inspired by the biomimic lotus leaves. The hydrophobic properties and wear-resistance of the coatings were measured by a contact angle meter and evaluated on a pin-on-disk friction and wear tester, respectively. Moreover, the surfaces of the PPS/PTFE composite coatings were investigated by means of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), and thermogravimetry (TG) analysis. Results showed that the highest contact angle of the PPS/PTFE surface, with papillae-like randomly distributed double-scale structure, could reach up to 162°. When 1 wt.% PDMS was added, the highest contact angle could hold is 172°. The coatings also retained superhydrophobicity, even under high temperature environment. The investigation also indicated that the coatings were not only superhydrophobic but also oleophobic behavior at room temperature, such as the crude oil, glycerol, and oil-water mixture. The PPS/45%PTFE coatings had more stable friction coefficient and excellent wear-resistance (331,407 cycles) compared with those with less than 45% of PTFE. Copyright © 2012 Elsevier Inc. All rights reserved.

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

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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.

THE CORROSION BEHAVIOR AND WEAR RESISTANCE OF GRAY CAST IRON

Directory of Open Access Journals (Sweden)

Lina F. Kadhim

2018-01-01

Full Text Available Gray cast iron has many applications as pipes , pumps and valve bodies where it has influenced by heat and contact with other solutions . This research has studied the corrosion behavior and Vickers hardness of gray cast iron by immersion in four strong alkaline solutions (NaOH, KOH, Ca(OH2, LiOHwith three concentrations (1%,2%,3% of each solution. Dry sliding wear has carried out before and after the heat treatments (stress relief ,normalizing, hardening and tempering. In this work ,maximum wear strength has obtained at tempered gray cast iron and minimum corrosion rate has obtained in LiOH solution by forming protective white visible oxide layer.

Quantitive dynamical wear analysis and the convergent quest for significant wear reduction

International Nuclear Information System (INIS)

Sellschop, F.; Kirsch, J.; Derry, T.; Marcus, R.

1984-01-01

The maturing of nuclear physics has made the development of ion beam modification of materials possible, bringing new skills and prospects to the world of materials science. In the following paper an outline is given of the history of ion beam modification of materials (IBMM) and its use for altering the surface of metals to combat wear and friction, and monitoring wear in engines

Study of Tool Wear Mechanisms and Mathematical Modeling of Flank Wear During Machining of Ti Alloy (Ti6Al4V)

Science.gov (United States)

Chetan; Narasimhulu, A.; Ghosh, S.; Rao, P. V.

2015-07-01

Machinability of titanium is poor due to its low thermal conductivity and high chemical affinity. Lower thermal conductivity of titanium alloy is undesirable on the part of cutting tool causing extensive tool wear. The main task of this work is to predict the various wear mechanisms involved during machining of Ti alloy (Ti6Al4V) and to formulate an analytical mathematical tool wear model for the same. It has been found from various experiments that adhesive and diffusion wear are the dominating wear during machining of Ti alloy with PVD coated tungsten carbide tool. It is also clear from the experiments that the tool wear increases with the increase in cutting parameters like speed, feed and depth of cut. The wear model was validated by carrying out dry machining of Ti alloy at suitable cutting conditions. It has been found that the wear model is able to predict the flank wear suitably under gentle cutting conditions.

The effect of laser treatment on the wear resistance of steel in corrosive media

International Nuclear Information System (INIS)

Plyatsko, G.V.; Porter, A.I.; Prejs, G.A.; Mojsa, M.I.

1975-01-01

The corrosion mechanical wearing properties of steel 45 treated with a laser beam (H 100 =7800 Mn/sq.m) under friction with nitrated steel 40KhNMA (HV=7000 Mn/sq.m), chrome cast iron Kh15M (hardened and low-temperature tempered, modified), perlite cast iron and bronze are studied. The aqueous buffers with pH=6 and 11 are used as a corrosion active media. In a weakly acid medium the most intensive wearing of steel 40KhNMA is observed at P=8 Mn/sq.m. Its wearing reduces due to increase of pressure to 12 Mn/sq.m. Extent of steel 45 wearing increases with pressure increase from 8 to 12 Mn/sg.m. Friction coefficient of this pair changes by jumps at an increase of normal pressure and its variation range is smaller than that observed in an alkaline medium. The maximum value of friction coefficient is shifted to the higher pressure. The wearing of cast iron Kh15M-steel 45 pair has an alternative pattern. In an alkaline medium the cast iron wearing intensity shows a linear increase with the normal contact pressure but that of the steel changes jumpwise attaining extreme at 8 and 12 Mn/sq.m. In a weak acid medium the intensity of grasping and graphitization at the friction surface of cast iron Kh15M-steel 45 pair is higher than that in the alkaline medium. Experiments demonstrate an effectiveness of the laser beam treatment of steel 45 for its friction in the alkaline medium with nitrated steel 40KhNMA and with hardened low-temperature tempered cast iron 45 under friction contact pressure as high as 8 Mn/sq.m, and in acid medium at 12 and 8 Mn/sq.m respectively. The laser treatment provides high corrosion-mechanical stability of steel 45 and the counterbodies described, as well as the low friction coefficient of these pairs

Tool wear in terms of vibration effects in milling medium-density fibreboard with an industrial robot

International Nuclear Information System (INIS)

Tratar, Janez; Pusavec, Franci; Kopac, Janez

2014-01-01

Machining with robots represents a promising, highly flexible and cost effective alternative to standard machining and hand labour applications when machining mid tolerance soft material end products. One of the most challenging issues is to know the vibration characteristics in milling with the robots which greatly affect tool life. In general the technological bases of tool life expectancy while milling with robot arms are not available or studied. That's why the purpose of this paper is to investigate the influence of attained vibrations analysis during the milling process and correlated tool wear. Primarily the study is focused on tool wear according to the distance between the milling position and the robot's base. Results show that increasing distance between the robot's base and the milling position significantly affects tool wear because of the attained vibrations in proportion to the increasing distance respectively. Tool wear has also proved to be greater in comparison to machining with CNC machine and applicable new information for woodworking industry.

High temperature tribological behaviour of carbon based (B{sub 4}C and DLC) coatings in sliding contact with aluminum

Energy Technology Data Exchange (ETDEWEB)

Gharam, A. Abou, E-mail: abougha@uwindsor.c [Mechanical Automotive and Materials Engineering Department, University of Windsor, Windsor, ON, N9B3P4 (Canada); Lukitsch, M.J.; Balogh, M.P. [Chemical Sciences and Materials Systems Laboratory, General Motors R and D Center, 30500 Mound Road, Warren, MI 48090-9055 (United States); Alpas, A.T. [Mechanical Automotive and Materials Engineering Department, University of Windsor, Windsor, ON, N9B3P4 (Canada)

2010-12-30

Carbon based coatings, particularly diamond-like carbon (DLC) films are known to resist aluminum adhesion and reduce friction at room temperature. This attractive tribological behaviour is useful for applications such as tool coatings used for aluminum forming and machining. However, for those operations that are performed at elevated temperatures (e.g. hot forming) or that generate frictional heat during contact (e.g. dry machining) the suitable coatings are required to maintain their tribological properties at high temperatures. Candidates for these demanding applications include boron carbide (B{sub 4}C) and DLC coatings. An understanding of the mechanisms of friction, wear and adhesion of carbon based coatings against aluminum alloys at high temperatures will help in designing coatings with improved high temperature tribological properties. With this goal in mind, this study focused on B{sub 4}C and a hydrogenated DLC coatings sliding against a 319 grade cast aluminum alloy by performing pin-on-disk experiments at temperatures up to 400 {sup o}C. Experimental results have shown that the 319 Al/B{sub 4}C tribosystem generated coefficient of friction (COF) values ranging between 0.42 and 0.65, in this temperature range. However, increased amounts of aluminum adhesion were detected in the B{sub 4}C wear tracks at elevated temperatures. Focused ion beam (FIB) milled cross sections of the wear tracks revealed that the coating failed due to shearing along the columnar grain boundaries of the coating. The 319 Al/DLC tribosystem maintained a low COF (0.15-0.06) from room temperature up to 200 {sup o}C. This was followed by an abrupt increase to 0.6 at 400 {sup o}C. The deterioration of friction behaviour at T > 200 {sup o}C was attributed to the exhaustion of hydrogen and hydroxyl passivants on the carbon transfer layer formed on the Al pin.

Effect of wear parameters on dry sliding behavior of Fly Ash/SiC particles reinforced AA 2024 hybrid composites

Science.gov (United States)

Bhaskar Kurapati, Vijaya; Kommineni, Ravindra

2017-09-01

In the present work AA 2024 alloy reinforced with mixtures of SiC and Fly Ash (FA) particles of 70 µm (5, 10 and 15 wt. %) are fabricated using the stir casting method. Both reinforcements are added in equal weight proportions. The wear test specimens are prepared from both the alloy and composite castings in the dimensions of Ф 4 mm and 30 mm lengths by the wire cut EDM process. The dry sliding wear properties of the prepared composites at room temperature are estimated by pin-on-disc wear testing equipment. The wear characteristics of the composites are studied by conducting the dry sliding wear test over loads of 0.5 Kgf, 1.0 Kgf, 1.5 Kgf, a track diameter of 60 mm and sliding times of 15 min, 30 min, 45min. The experimental results shows that the wear decreases with an increase in the weight percentage of FA and SiC particles in the matrix. Additionally wear increases with an increase in load and sliding time. Further, it is found that the wear resistance of the AA2024-Hybrid composites is higher than that of the AA2024 matrix.

A new ball-on-disk vacuum tribometer with in situ measurement of the wear track by digital holographic microscopy

Science.gov (United States)

Meylan, B.; Ciani, D.; Zhang, B.; Cuche, E.; Wasmer, K.

2017-12-01

This contribution presents a new ball-on-disk vacuum tribometer with in situ measurement of the wear track by digital holographic microscopy. This new tribometer allows observation of the evolution of the wear track in situ and in real-time. The method combines a high vacuum high temperature ball-on-disk tribometer with a digital holographic microscope (DHM). The machine was tested and validated by taking DHM images during wear tests at room temperature and in vacuum at 2 · 10-6 of polished 100Cr6 steel disks. We demonstrated that the DHM system is well suited to monitor the evolution of the wear track during sliding. We found that, with an acquisition time of 0.1 ms for the DHM, the maximal linear speed is 10 cm s-1 to have reliable images. We proved, via scanning electron microscope (SEM) pictures, that the lines in the sliding direction in all DHM images exist. We also validated the new tribometer by having an excellent correlation between the images and profiles of the wear track taken by the DHM with the ones from a confocal microscope. Finally, the new tribometer combined with the DHM has four advantages. It can test under vacuum and various atmospheric conditions. The evolution of the wear track is measured in situ and in real-time. Hence, the problem of replacing the sample is avoided. Thanks to the DHM technology, the vertical accuracy of the topographical measurement is 4 nm.

Surface Roughness and Tool Wear on Cryogenic Treated CBN Insert on Titanium and Inconel 718 Alloy Steel

International Nuclear Information System (INIS)

Thamizhmanii, S; Mohideen, R; Zaidi, A M A; Hasan, S

2015-01-01

Machining of materials by super hard tools like cubic boron nitride (cbn) and poly cubic boron nitride (pcbn) is to reduce tool wear to obtain dimensional accuracy, smooth surface and more number of parts per cutting edge. wear of tools is inevitable due to rubbing action between work material and tool edge. however, the tool wear can be minimized by using super hard tools by enhancing the strength of the cutting inserts. one such process is cryogenic process. this process is used in all materials and cutting inserts which requires wear resistance. the cryogenic process is executed under subzero temperature -186° celsius for longer period of time in a closed chamber which contains liquid nitrogen. in this research, cbn inserts with cryogenically treated was used to turn difficult to cut metals like titanium, inconel 718 etc. the turning parameters used is different cutting speeds, feed rates and depth of cut. in this research, titanium and inconel 718 material were used. the results obtained are surface roughness, flank wear and crater wear. the surface roughness obtained on titanium was lower at high cutting speed compared with inconel 718. the flank wear was low while turning titanium than inconel 718. crater wear is less on inconel 718 than titanium alloy. all the two materials produced saw tooth chips. (paper)

Tooth Wear Inclination in Great Ape Molars.

Science.gov (United States)

Knight-Sadler, Jordan; Fiorenza, Luca

2017-01-01

Primate dietary diversity is reflected in their dental morphology, with differences in size and shape of teeth. In particular, the tooth wear angle can provide insight into a species' ability to break down certain foods. To examine dietary and masticatory information, digitized polygon models of dental casts provide a basis for quantitative analysis of wear associated with tooth attrition. In this study, we analyze and compare the wear patterns of Pongo pygmaeus, Gorilla gorillagorilla and Pan troglodytes schweinfurthii lower molars, focusing on the degree of inclination of specific wear facets. The variation in wear angles appears to be indicative of jaw movements and the specific stresses imposed on food during mastication, reflecting thus the ecology of these species. Orangutans exhibit flatter wear angles, more typical of a diet consisting of hard and brittle foods, while gorillas show a wear pattern with a high degree of inclination, reflecting thus their more leafy diet. Chimpanzees, on the other hand, show intermediate inclinations, a pattern that could be related to their highly variable diet. This method is demonstrated to be a powerful tool for better understanding the relationship between food, mastication and tooth wear processes in living primates, and can be potentially used to reconstruct the diet of fossil species. © 2017 S. Karger AG, Basel.

Multiscale Modeling of Wear Degradation

KAUST Repository

Moraes, Alvaro; Ruggeri, Fabrizio; Tempone, Raul; Vilanova, Pedro

2014-01-01

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

Wear Behavior of Aluminium Metal Matrix Composite Prepared from Industrial Waste

Directory of Open Access Journals (Sweden)

L. Francis Xavier

2016-01-01

Full Text Available With an increase in the population and industrialization, a lot of valuable natural resources are depleted to prepare and manufacture products. However industrialization on the other hand has waste disposal issues, causing dust and environmental pollution. In this work, Aluminium Metal Matrix Composite is prepared by reinforcing 10 wt% and 20 wt% of wet grinder stone dust particles an industrial waste obtained during processing of quarry rocks which are available in nature. In the composite materials design wear is a very important criterion requiring consideration which ensures the materials reliability in applications where they come in contact with the environment and other surfaces. Dry sliding wear test was carried out using pin-on-disc apparatus on the prepared composites. The results reveal that increasing the reinforcement content from 10 wt% to 20 wt% increases the resistance to wear rate.

On the debris-level origins of adhesive wear.

Science.gov (United States)

Aghababaei, Ramin; Warner, Derek H; Molinari, Jean-François

2017-07-25

Every contacting surface inevitably experiences wear. Predicting the exact amount of material loss due to wear relies on empirical data and cannot be obtained from any physical model. Here, we analyze and quantify wear at the most fundamental level, i.e., wear debris particles. Our simulations show that the asperity junction size dictates the debris volume, revealing the origins of the long-standing hypothesized correlation between the wear volume and the real contact area. No correlation, however, is found between the debris volume and the normal applied force at the debris level. Alternatively, we show that the junction size controls the tangential force and sliding distance such that their product, i.e., the tangential work, is always proportional to the debris volume, with a proportionality constant of 1 over the junction shear strength. This study provides an estimation of the debris volume without any empirical factor, resulting in a wear coefficient of unity at the debris level. Discrepant microscopic and macroscopic wear observations and models are then contextualized on the basis of this understanding. This finding offers a way to characterize the wear volume in atomistic simulations and atomic force microscope wear experiments. It also provides a fundamental basis for predicting the wear coefficient for sliding rough contacts, given the statistics of junction clusters sizes.

Design of a wearable bio-patch for monitoring patient's temperature.

Science.gov (United States)

Vicente, Jose M; Avila-Navarro, Ernesto; Juan, Carlos G; Garcia, Nicolas; Sabater-Navarro, Jose M

2016-08-01

New communication technologies allow us developing useful and more practical medical applications, in particular for ambulatory monitoring. NFC communication has the advantages of low powering and low influence range area, what makes this technology suitable for health applications. This work presents an explanation of the design process of planar NFC antennas in a wearable biopatch. The problem of optimizing the communication distance is addressed. Design of a biopatch for continuous temperature monitoring and experimental results obtained wearing this biopatch during daily activities are presented.

High temperature tribological properties of plasma-sprayed metallic coatings containing ceramic particles

International Nuclear Information System (INIS)

Dallaire, S.; Legoux, J.G.

1995-01-01

For sealing a moving metal component with a dense silica-based ceramic pre-heated at 800 C, coatings with a low coefficient of friction and moderate wear loss are required. As reported previously, plasma-sprayed coatings containing solid lubricants could reduce sliding wear in high-temperature applications. Plasma-sprayed metal-based coatings containing ceramic particles have been considered for high temperature sealing. Selected metal powders (NiCoCrAlY, CuNi, CuNiIn, Ag, Cu) and ceramic particles (boron nitride, Zeta-B ceramic) were agglomerated to form suitable spray powders. Plasma-sprayed composite coatings and reference materials were tested in a modified pin-on-disc apparatus in which the stationary disc consisted of a dense silica-based ceramic piece initially heated at 800 C and allowed to cool down during tests. The influence of single exposure and repeated contacts with a dense silica-based ceramic material pre-heated to 800 C on the coefficient of friction, wear loss and damage to the ceramic piece was evaluated. Being submitted to a single exposure at high temperature, coatings containing malleable metals such as indium, silver and copper performed well. The outstanding tribological characteristics of the copper-Zeta-B ceramic coating was attributed to the formation of a glazed layer on the surface of this coating which lasted over exposures to high temperature. This glazed layer, composed of fine oxidation products, provided a smooth and polished surface and helped maintaining the coefficient of friction low

Development of Eddy Current Technique for Reactor In-Core Flux Thimble Wear

International Nuclear Information System (INIS)

Park, S. S.; Jang, Y. Y.; Yim, C. Y.; Park, K. H.

1990-01-01

Since in-core flux thimble tube wear the due to flow-induced vibration could degrade the integrity of nuclear reactor, the effective detection and interpretation of the wear is important. In order to establish an inspection technique for thimble tubes, an eddy current experiment was performed to determine the optimum test frequency, defect sensitivity and evaluation accuracy. Eddy current probes were designed and fabricated with a theory. Specimens with artificial defects were fabricated using electro discharge machining method. The results from inspection technique developed and on-site inspection showed good applicability

Elevated temperature erosive wear of metallic materials

International Nuclear Information System (INIS)

Roy, Manish

2006-01-01

Solid particle erosion of metals and alloys at elevated temperature is governed by the nature of the interaction between erosion and oxidation, which, in turn, is determined by the thickness, pliability, morphology, adhesion characteristics and toughness of the oxide scale. The main objective of this paper is to critically review the present state of understanding of the elevated temperature erosion behaviour of metals and alloys. First of all, the erosion testing at elevated temperature is reviewed. This is followed by discussion of the essential features of elevated temperature erosion with special emphasis on microscopic observation, giving details of the erosion-oxidation (E-O) interaction mechanisms. The E-O interaction has been elaborated in the subsequent section. The E-O interaction includes E-O maps, analysis of transition criteria from one erosion mechanism to another mechanism and quantification of enhanced oxidation kinetics during erosion. Finally, the relevant areas for future studies are indicated. (topical review)

Effects of a whole-body spandex garment on rectal temperature and oxygen consumption in healthy dogs.

Science.gov (United States)

Reimer, S Brent; Schulz, Kurt S; Mason, David R; Jones, James H

2004-01-01

To determine whether a full-body spandex garment would alter rectal temperatures of healthy dogs at rest in cool and warm environments. Prospective study. 10 healthy dogs. Each dog was evaluated at a low (20 degrees to 25 degrees C [68 degrees to 77 degrees F]) or high (30 degrees to 35 degrees C [86 degrees to 95 degrees F]) ambient temperature while wearing or not wearing a commercially available whole-body spandex garment designed for dogs. Oxygen consumption was measured by placing dogs in a flow-through indirect calorimeter for 90 to 120 minutes. Rectal temperature was measured before dogs were placed in the calorimeter and after they were removed. Rectal temperature increased significantly more at the higher ambient temperature than at the lower temperature and when dogs were not wearing the garment than when they were wearing it. The specific rate of oxygen consumption was significantly higher at the lower ambient temperature than at the higher temperature. Results suggest that wearing a snug spandex body garment does not increase the possibility that dogs will overheat while in moderate ambient temperatures. Instead, wearing such a garment may enable dogs to better maintain body temperature during moderate heat loading. These results suggest that such garments might be used for purposes such as wound or suture protection without causing dogs to overheat.

Wear Behavior and Self Tribofilm Formation of Infiltration-Type TiC/FeCrWMoV Metal Ceramics Under Dry Sliding Conditions

DEFF Research Database (Denmark)

Wang, Yanjun; Yang, Zhenyu; Han, Liying

2015-01-01

infiltration furnace. The friction and wear behaviors of the composites were investigated using a pin-on-disk high temperature wear testing machine at different temperature (up to 800°C). The compositions, images and structures of worn surfaces were analyzed by means of scanning electron microscope (SEM...... PbMoO4, PbO, SnWO4, Ag2WO4 and Ag3Sn. The formation of lubrication film containing of these oxides and of intermetallic compounds was the main reason that the composites had good self-lubrication properties at high temperature. It was considered that the micro-pores on friction surface would...

Application of High Temperature Superconductors to Accelerators

CERN Document Server

Ballarino, A

2000-01-01

Since the discovery of high temperature superconductivity, a large effort has been made by the scientific community to investigate this field towards a possible application of the new oxide superconductors to different devices like SMES, magnetic bearings, flywheels energy storage, magnetic shielding, transmission cables, fault current limiters, etc. However, all present day large scale applications using superconductivity in accelerator technology are based on conventional materials operating at liquid helium temperatures. Poor mechanical properties, low critical current density and sensitivity to the magnetic field at high temperature are the key parameters whose improvement is essential for a large scale application of high temperature superconductors to such devices. Current leads, used for transferring currents from the power converters, working at room temperature, into the liquid helium environment, where the magnets are operating, represent an immediate application of the emerging technology of high t...

Wear protection in cutting tool applications by PACVD (Ti,Al)N and Al2O3 coatings

International Nuclear Information System (INIS)

Kathrein, M.; Heiss, M.; Rofner, R.; Schleinkofer, U.; Schintlmeister, W.; Schatte, J.; Mitterer, C.

2001-01-01

Various (Ti,Al)N-, Al 2 O 3 -, and (Ti,Al)N/Al 2 O 3 multilayer coatings were deposited onto cemented carbide cutting tool inserts by a plasma assisted chemical vapor deposition (PACVD) technique. Al 2 O 3 coatings were deposited using the gaseous mixture AlCl 3 , Ar, H 2 , and O 2 . (Ti,Al)N intermediate layers were deposited in the same device using the process mentioned and the gases AICl 3 , Ar, H 2 , TiCl 4 and N 2 . The unique properties of (Ti,Al)N/Al 2 O 3 multilayer coatings result in superior wear protection for cutting inserts applied in severe multifunction cutting processes. The influence of different deposition temperatures an structure and properties of the coatings like crystallographic phases, chemical composition, mechanical and technological properties is shown. PACVD (Ti,Al)N/Al 2 O 3 coated cutting inserts with fine grained crystalline α/κ-Al 2 O 3 offer performance advantages which are superior with respect to coatings deposited by chemical vapor deposition (CVD) due to the low deposition temperature applied. (author)

The effects of vanadium on the microstructure and wear resistance of centrifugally cast Ni-hard rolls

International Nuclear Information System (INIS)

Kang, Minwoo; Suh, Yongchan; Oh, Yong-Jun; Lee, Young-Kook

2014-01-01

Highlights: • V addition changed the pro-eutectic phase from austenite to vermicular (V,Nb)C. • Pro-eutectic (V,Nb)C particles were segregated to the inner part of the roll. • Wear loss was inversely proportional to MC fraction under the same graphite fraction. • Cementite particles acted as the initiation site and propagation path of cracks. • High-temperature wear sequence of centrifugally cast Ni-hard rolls was suggested. - Abstract: The effects of V on the microstructure and wear resistance of centrifugally cast Ni-hard rolls are investigated under a constant fraction of graphite using electron microscopes and a revolving disk-type high-temperature wear tester. The volume fraction of (V,Nb)C particles was increased at the expense of the volume fraction of cementite with an increase in the V concentration. However, the volume fraction of graphite was held nearly constant by controlling the concentration ratio of Si and Cr. As the V concentration was higher than 3 wt.%, the pro-eutectic phase was changed from austenite to (V,Nb)C carbide. The pro-eutectic vermicular (V,Nb)C particles were segregated to the inner part of the roll during centrifugal casting. The wear resistance was improved with an addition of V due to the high volume fractions of the coarse eutectic and pro-eutectic (V,Nb)C particles and the precipitation hardening of fine (V,Nb)C particles in the martensitic matrix. The worn surface showed that cementite particles acted as the initiation site and propagation route of cracks

Wear and impact resistance of HVOF sprayedceramic matrix composites coating

Science.gov (United States)

Prawara, B.; Martides, E.; Priyono, B.; Ardy, H.; Rikardo, N.

2016-02-01

Ceramic coating has the mechanical properties of high hardness and it is well known for application on wear resistance, but on the other hand the resistance to impact load is low. Therefore its use is limited to applications that have no impact loading. The aim of this research was to obtain ceramic-metallic composite coating which has improved impact resistance compared to conventional ceramic coating. The high impact resistance of ceramic-metallic composite coating is obtained from dispersed metallic alloy phase in ceramic matrix. Ceramic Matrix Composites (CMC) powder with chrome carbide (Cr3C2) base and ceramic-metal NiAl-Al2O3 with various particle sizes as reinforced particle was deposited on mild steel substrate with High Velocity Oxygen Fuel (HVOF) thermal spray coating. Repeated impact test showed that reinforced metallic phase size influenced impact resistance of CMC coating. The ability of CMC coating to absorb impact energy has improved eight times and ten times compared with original Cr3C2 and hard chrome plating respectively. On the other hand the high temperature corrosion resistance of CMC coating showed up to 31 cycles of heating at 800°C and water quenching cooling.

Development of bushing material with higher corrosion and wear resistance; Taishoku taimamosei dogokin bush zairyo no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Kira, T; Yokota, H; Kamiya, S [Taiho Kogyo Co. Ltd., Osaka (Japan)

1997-10-01

Recent diesel engines require a higher performance and a longer life. Due to higher cylinder pressure, the operating load and temperature of piston pin bushings become higher. Therefore, higher load capacity, higher wear resistance and higher corrosion resistance are required for piston pin bushings. For this reason, we have studied the effect of components added to copper alloy upon the corrosion resistance and the effect of hard particles dispersed in copper matrix upon the wear resistance and the influence of hard particles on the machinablity of materials. Based on the experimental results, we have developed a new bushing material improving wear and corrosion resistance. 17 figs., 3 tabs.

Improved dental implant drill durability and performance using heat and wear resistant protective coatings.

Science.gov (United States)

Er, Nilay; Alkan, Alper; İlday, Serim; Bengu, Erman

2018-03-02

Dental implant drilling procedure is an essential step for implant surgery and frictional heat appeared in bone during drilling is a key factor affecting the success of an implant. The aim of this study is to increase the dental implant drill lifetime and performance using heat- and wear-resistant protective coatings hence to decrease the alveolar bone temperature caused by the dental implant drilling procedure. Commercially obtained stainless steel drills were coated with titanium aluminum nitride, diamond-like carbon, titanium boron nitride, and boron nitride coatings via magnetron-sputter deposition. Drilling procedure was performed on a bovine femoral cortical bone under the conditions mimicking clinical practice, where the tests were performed both under water-assisted cooling and under the conditions without any cooling was applied. Coated drill performances and durabilities were compared to that of three commonly used commercial drills which surfaces are made from namely; zirconia, black diamond and stainless steel. Protective coatings with boron nitride, titanium boron nitride and diamond-like carbon have significantly improved drill performance and durability. Especially boron nitride-coated drills have performed within safe bone temperature limits for 50 drillings even without any cooling is applied. Titanium aluminium nitride coated drills did not show any improvement over commercially obtained stainless steel drills. Surface modification using heat and wear resistant coatings is an easy and highly effective way to improve implant drill performance and durability, which can reflect positively on surgical procedure and healing period afterwards. The noteworthy success of different types of coatings is novel and likely to be applicable to various other medical systems.

Vibrational characteristics and wear of fuel rods

International Nuclear Information System (INIS)

Schmugar, K.L.

1977-01-01

Fuel rod wear, due to vibration, is a continuing concern in the design of liquid-cooled reactors. In my report, the methodology and models that are used to predict fuel rod vibrational response and vibratory wear, in a light water reactor environment, are discussed. This methodology is being followed at present in the design of Westinghouse Nuclear Fuel. Fuel rod vibrations are expressed as the normal bending modes, and sources of rod vibration are examined with special emphasis on flow-induced mechanisms in the stable flow region. In a typical Westinghouse PWR fuel assembly design, each fuel rod is supported at multiple locations along the rod axis by a square-shaped 'grid cell'. For a fuel rod /grid support system, the development of small oscillatory motions, due to fluid flow at the rod/grid interface, results in material wear. A theoretical wear mode is developed using the Archard Theory of Adhesive Wear as the basis. Without question certainty, fretting wear becomes a serious problem if it progresses to the stage where the fuel cladding is penetrated and fuel is exposed to the coolant. Westinghouse fuel is designed to minimize fretting wear by limiting the relative motion between the fuel rod and its supports. The wear producing motion between the fuel rod and its supports occurs when the vibration amplitude exceeds the slippage threshold amplitude

Study on Co-free amorphous material cladding using a laser beam to improve the resistance of primary system parts in NPPs to wear/erosion-corrosion

International Nuclear Information System (INIS)

Kim, J. S.; Woo, S. S.; Seo, J. H.

2001-01-01

A study on Co-free amorphous material, ARMACOR M, cladding using a laser beam has been performed to improve resistance of the primary system main parts on nuclear power plants to wear/erosion-corrosion. The wear/erosion-corrosion properties of ARMACRO M cladded speciemens were characterized in air at room temperature and 300 .deg. C and in air at room temperature, and compared to those of other hardfacing materials, such as Stellite 6, NOREM 02, Deloro 50, TIG-welde or laer cladded. According to the results, ARMACOR M laser-cladded specimen showed to have the highest resistance to wear/erosion-corrosion

Wear characteristics of current aesthetic dental restorative CAD/CAM materials: two-body wear, gloss retention, roughness and Martens hardness.

Science.gov (United States)

Mörmann, Werner H; Stawarczyk, Bogna; Ender, Andreas; Sener, Beatrice; Attin, Thomas; Mehl, Albert

2013-04-01

This study determined the two-body wear and toothbrushing wear parameters, including gloss and roughness measurements and additionally Martens hardness, of nine aesthetic CAD/CAM materials, one direct resin-based nanocomposite plus that of human enamel as a control group. Two-body wear was investigated in a computer-controlled chewing simulator (1.2 million loadings, 49N at 1.7Hz; 3000 thermocycles 5/50°C). Each of the 11 groups consisted of 12 specimens and 12 enamel antagonists. Quantitative analysis of wear was carried out with a 3D-surface analyser. Gloss and roughness measurements were evaluated using a glossmeter and an inductive surface profilometer before and after abrasive toothbrushing of machine-polished specimens. Additionally Martens hardness was measured. Statistically significant differences were calculated with one-way ANOVA (analysis of variance). Statistically significant differences were found for two-body wear, gloss, surface roughness and hardness. Zirconium dioxide ceramics showed no material wear and low wear of the enamel antagonist. Two-body wear of CAD/CAM-silicate and -lithium disilicate ceramics, -hybrid ceramics and -nanocomposite as well as direct nanocomposite did not differ significantly from that of human enamel. Temporary polymers showed significantly higher material wear than permanent materials. Abrasive toothbrushing significantly reduced gloss and increased roughness of all materials except zirconium dioxide ceramics. Gloss retention was highest with zirconium dioxide ceramics, silicate ceramics, hybrid ceramics and nanocomposites. Temporary polymers showed least gloss retention. Martens hardness differed significantly among ceramics, between ceramics and composites, and between resin composites and acrylic block materials as well. All permanent aesthetic CAD/CAM block materials tested behave similarly or better with respect to two-body wear and toothbrushing wear than human enamel, which is not true for temporary polymer CAD

Application of x-ray diffraction techniques to the understanding of the dry sliding wear behaviour of aluminium and titanium

International Nuclear Information System (INIS)

Zoheir, N.; Ahmet, T.A.; Northwood, D.O.

1996-01-01

Dry sliding wear tests were performed on polycrystalline f.c.c. Al and h.c.p. Ti specimens using a block-on-ring type wear machine with a rotating ring made of 52100 bearing steel. The sliding speed was 0.13 m.s sup -l and the applied normal load was 10 N. The wear tests were performed on a single specimen in ambient conditions and the texture was evaluated during wear using an X-ray diffraction inverse pole figure technique at a range of sliding distances. Pole density distributions for the [0001] and [111) poles for of Ti and Al, respectively, were then determined from the inverse pole figures. The texture evolution during sliding wear was subsequently related to the friction and wear behaviour. For the aluminum sample, a (111) texture developed parallel to the worn surface with increasing sliding distance (a 6 fold increase in the (111) pole density as the sliding distance increases from 0 to 2714 m). The titanium sample (normal section) which had a preferred orientation with the basal poles, [0001), parallel to the contact surface prior to testing, an increase in wear, i.e. sliding distance, did not change the texture. However, for the transverse section of titanium, the basal pole, [0001), density parallel to the worn surface increased with increasing sliding distance. The shape of the coefficient of friction versus sliding distance curve is strongly influenced by crystallographic texturing. A drop in the coefficient of friction with the progressive development of the [111) and [0001) texture was observed for both Al and Ti (transverse section) specimens, respectively

Measurement of Wear in Radial Journal Bearings

NARCIS (Netherlands)

Ligterink, D.J.; Ligterink, D.J.; de Gee, A.W.J.

1996-01-01

this article, the measurement of wear in radial journal bearings is discussed, where a distinction is made between stationary and non-stationary contact conditions. Starting with Holm/Archard's wear law, equations are derived for the calculation of the specific wear rate k of the bearing material as

Combined Corrosion and Wear of Aluminium Alloy 7075-T6

NARCIS (Netherlands)

Liu, Y.; Mol, J.M.C.; Janssen, G.C.A.M.

2016-01-01

The aluminium alloy 7075-T6 is widely used in engineering. In some applications, like slurry transport, corrosion and abrasion occur simultaneously, resulting in early material failure. In the present work, we investigated the combined effect of corrosion and wear on the aluminium alloy 7075-T6. We

Electrodeposition of diamond-like carbon films on titanium alloy using organic liquids: Corrosion and wear resistance

International Nuclear Information System (INIS)

Falcade, Tiago; Shmitzhaus, Tobias Eduardo; Gomes dos Reis, Otávio; Vargas, André Luis Marin; Hübler, Roberto; Müller, Iduvirges Lourdes; Fraga Malfatti, Célia de

2012-01-01

Highlights: ► The electrodeposition may be conducted at room temperature. ► The DLC films have good resistance to corrosion in saline environments. ► The films have lower coefficient of friction than the uncoated substrate. ► The abrasive wear protection is evident in coated systems. - Abstract: Diamond-like carbon (DLC) films have been studied as coatings for corrosion protection and wear resistance because they have excellent chemical inertness in traditional corrosive environments, besides presenting a significant reduction in coefficient of friction. Diamond-like carbon (DLC) films obtained by electrochemical deposition techniques have attracted a lot of interest, regarding their potential in relation to the vapor phase deposition techniques. The electrochemical deposition techniques are carried out at room temperature and do not need vacuum system, making easier this way the technological transfer. At high electric fields, the organic molecules polarize and react on the electrode surface, forming carbon films. The aim of this work was to obtain DLC films onto Ti6Al4V substrate using as electrolyte: acetonitrile (ACN) and N,N-dimethylformamide (DMF). The films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman spectroscopy, potentiodynamic polarization and wear tests. The results show that these films can improve, significantly, the corrosion resistance of titanium and its alloys and their wear resistance.

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.

“Can I wear this?” : blending clothing and digital expression by wearing dynamic fabric

NARCIS (Netherlands)

Mackey, A.M.; Wakkary, R.L.; Wensveen, S.A.G.; Tomico Plasencia, O

2017-01-01

We explore the future scenario of wearing garments with digital display capabilities, or dynamic fabric, in everyday life. Our study, called Greenscreen Dress, investigates the experience of wearing dynamic fabric and how this type of garment quality might alter our daily interactions with clothing

Gaussian process regression for tool wear prediction

Science.gov (United States)

Kong, Dongdong; Chen, Yongjie; Li, Ning

2018-05-01

To realize and accelerate the pace of intelligent manufacturing, this paper presents a novel tool wear assessment technique based on the integrated radial basis function based kernel principal component analysis (KPCA_IRBF) and Gaussian process regression (GPR) for real-timely and accurately monitoring the in-process tool wear parameters (flank wear width). The KPCA_IRBF is a kind of new nonlinear dimension-increment technique and firstly proposed for feature fusion. The tool wear predictive value and the corresponding confidence interval are both provided by utilizing the GPR model. Besides, GPR performs better than artificial neural networks (ANN) and support vector machines (SVM) in prediction accuracy since the Gaussian noises can be modeled quantitatively in the GPR model. However, the existence of noises will affect the stability of the confidence interval seriously. In this work, the proposed KPCA_IRBF technique helps to remove the noises and weaken its negative effects so as to make the confidence interval compressed greatly and more smoothed, which is conducive for monitoring the tool wear accurately. Moreover, the selection of kernel parameter in KPCA_IRBF can be easily carried out in a much larger selectable region in comparison with the conventional KPCA_RBF technique, which helps to improve the efficiency of model construction. Ten sets of cutting tests are conducted to validate the effectiveness of the presented tool wear assessment technique. The experimental results show that the in-process flank wear width of tool inserts can be monitored accurately by utilizing the presented tool wear assessment technique which is robust under a variety of cutting conditions. This study lays the foundation for tool wear monitoring in real industrial settings.

Dynamic SEM wear studies of tungsten carbide cermets

Science.gov (United States)

Brainard, W. A.; Buckley, D. H.

1975-01-01

Dynamic friction and wear experiments were conducted in a scanning electron microscope. The wear behavior of pure tungsten carbide and composite with 6 and 15 weight percent cobalt binder was examined. Etching of the binder was done to selectively determine the role of the binder in the wear process. Dynamic experiments were conducted as the WC and bonded WC cermet surfaces were transversed by a 50 micron radiused diamond stylus. These studies show that the predominant wear process in WC is fracture initiated by plastic deformation. The wear of the etched cermets is similar to pure WC. The presence of the cobalt binder reduces both friction and wear. The cementing action of the cobalt reduces granular separation and promotes a dense polished layer because of its low shear strength film-forming properties. The wear debris generated from unetched surface is approximately the same composition as the bulk.

Development of counting system for wear measurements using Thin Layer Activation and the Wearing Apparatus

Energy Technology Data Exchange (ETDEWEB)

França, Michel de A.; Suita, Julio C.; Salgado, César M., E-mail: mchldante@gmail.com, E-mail: suita@ien.gov.br, E-mail: otero@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

This paper focus on developing a counting system for the Wearing Apparatus, which is a device previously built to generate measurable wear on a given surface (Main Source) and to carry the fillings from it to a filter (second source). The Thin Layer Activation is a technique used to produce activity on one of the Wearing Apparatus' piece, this activity is proportional to the amount of material worn, or scrapped, from the piece's surface. Thus, by measuring the activity on those two points it is possible to measure the produced wear. The methodology used in this work is based on simulations through MCNP-X Code to nd the best specifications for shielding, solid angles, detectors dimensions and collimation for the Counting System. By simulating several scenarios, each one different from the other, and analyzing the results in the form of Counts Per Second, the ideal counting system's specifications and geometry to measure the activity in the Main Source and the Filter (second source) is chosen. After that, a set of previously activated stainless steel foils were used to reproduce the real experiments' conditions, this real experiment consists of using TLA and the Wearing Apparatus, the results demonstrate that the counting system and methodology are adequate for such experiments. (author)

A Comparative Study on the Formation Mechanism of Wear Scars during the Partial and Full Scale Fretting Wear Tests of Spacer Grids

Energy Technology Data Exchange (ETDEWEB)

Lee, Young Ho; Shin, Chang Hwan; Oh, Dong Seok; Kang, Heung Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-05-15

Fretting wear studies for evaluating the contact damages of nuclear fuel rods have been focused on the contact shape, rod motion, contact condition, environment, etc.. However, fretting wear mechanism was dramatically changed with slight variation of test variables such as test environments and contact shapes. For example, in an unlubricated condition, effects of wear debris and/or its layer on the fretting wear mechanism showed that the formation of a well-developed layer on the contact surfaces has a beneficial effect for decreasing a friction coefficient. Otherwise, a severe wear was happened due to a third body abrasion. In addition, in water lubrication condition, some of wear debris was remained on worn surface of fuel rod specimens at both sliding and impacting loading conditions. So, it is apparent that a wear rate of fuel rod specimen was easily accelerated by the third-body abrasion. This is because the restrained agglomeration behavior between generated wear particles results in rapid removal of wear debris and its layer. In case of contact shape effects, previous studies show that wear debris are easily trapped between contact surfaces and its debris layer was well developed in a localized area especially in a concave spring rather than a convex spring shape. Consequently, localized wear was happened at both ends of a concave spring and center region of a convex spring. So, it is useful for determining the fretting wear resistance of spacer gird spring and dimple by using part unit in the various lubricated conditions. It is well known that the fretting wear phenomenon of nuclear fuel rod is originated from a flow-induced vibration (FIV) due to the rapid primary coolant. This means that both rod vibration and debris removal behavior were affected by flow fields around the contact regions between fuel rod and spring/dimple. However, all most of the fretting tests were performed by simulating rod vibrating motions such as axial vibration, conservative rod

A Comparative Study on the Formation Mechanism of Wear Scars during the Partial and Full Scale Fretting Wear Tests of Spacer Grids

International Nuclear Information System (INIS)

Lee, Young Ho; Shin, Chang Hwan; Oh, Dong Seok; Kang, Heung Seok

2012-01-01

Fretting wear studies for evaluating the contact damages of nuclear fuel rods have been focused on the contact shape, rod motion, contact condition, environment, etc.. However, fretting wear mechanism was dramatically changed with slight variation of test variables such as test environments and contact shapes. For example, in an unlubricated condition, effects of wear debris and/or its layer on the fretting wear mechanism showed that the formation of a well-developed layer on the contact surfaces has a beneficial effect for decreasing a friction coefficient. Otherwise, a severe wear was happened due to a third body abrasion. In addition, in water lubrication condition, some of wear debris was remained on worn surface of fuel rod specimens at both sliding and impacting loading conditions. So, it is apparent that a wear rate of fuel rod specimen was easily accelerated by the third-body abrasion. This is because the restrained agglomeration behavior between generated wear particles results in rapid removal of wear debris and its layer. In case of contact shape effects, previous studies show that wear debris are easily trapped between contact surfaces and its debris layer was well developed in a localized area especially in a concave spring rather than a convex spring shape. Consequently, localized wear was happened at both ends of a concave spring and center region of a convex spring. So, it is useful for determining the fretting wear resistance of spacer gird spring and dimple by using part unit in the various lubricated conditions. It is well known that the fretting wear phenomenon of nuclear fuel rod is originated from a flow-induced vibration (FIV) due to the rapid primary coolant. This means that both rod vibration and debris removal behavior were affected by flow fields around the contact regions between fuel rod and spring/dimple. However, all most of the fretting tests were performed by simulating rod vibrating motions such as axial vibration, conservative rod

Wear rate quantifying in real-time using the charged particle surface activation

Science.gov (United States)

Alexandreanu, B.; Popa-Simil, L.; Voiculescu, D.; Racolta, P. M.

1997-02-01

Surface activation, commonly known as Thin Layer Activation (TLA), is currently employed in over 30 accelerator laboratories around the world for wear and/or corrosion monitoring in industrial plants [1-6]. TLA was primarily designed and developed to meet requirements of potential industrial partners, in order to transfer this technique from research to industry. The method consists of accelerated ion bombardment of a surface of interest, e.g., a machine part subjected to wear. Loss of material owing to wear, erosive corrosion or abrasion is characterized by monitoring the resultant changes in radioactivity. In principle, depending upon the case at hand, one may choose to measure either the remnant activity of the component of interest or to monitor the activity of the debris. For applications of the second type, especially when a lubricating agent is involved, dedicated installations have been constructed and adapted to an engine or a tribological testing stand in order to assure oil circulation around an externally placed detection gauge. This way, the wear particles suspended in the lubricant can be detected and the material loss rates quantified in real time. Moreover, in specific cases, such as the one presented in this paper, remnant activity measurements prove to be useful tools for complementary results. This paper provides a detailed presentation of such a case: in situ resistance-to-wear testing of two types of piston rings.

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

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