Influence of ceramic surface texture on the wear of gold alloy and heat-pressed ceramics.

Science.gov (United States)

Saiki, Osamu; Koizumi, Hiroyasu; Nogawa, Hiroshi; Hiraba, Haruto; Akazawa, Nobutaka; Matsumura, Hideo

2014-01-01

The purpose of this study was to evaluate the influence of ceramic surface texture on the wear of rounded rod specimens. Plate specimens were fabricated from zirconia (ZrO2), feldspathic porcelain, and lithium disilicate glass ceramics (LDG ceramics). Plate surfaces were either ground or polished. Rounded rod specimens with a 2.0-mm-diameter were fabricated from type 4 gold alloy and heat-pressed ceramics (HP ceramics). Wear testing was performed by means of a wear testing apparatus under 5,000 reciprocal strokes of the rod specimen with 5.9 N vertical loading. The results were statistically analyzed with a non-parametric procedure. The gold alloy showed the maximal height loss (90.0 µm) when the rod specimen was abraded with ground porcelain, whereas the HP ceramics exhibited maximal height loss (49.8 µm) when the rod specimen was abraded with ground zirconia. There was a strong correlation between height loss of the rod and surface roughness of the underlying plates, for both the gold alloy and HP ceramics.

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.

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)

A simple surrogate test method to rank the wear performance of prospective ceramic materials under hip prosthesis edge-loading conditions.

Science.gov (United States)

Sanders, Anthony P; Brannon, Rebecca M

2014-02-01

This research has developed a novel test method for evaluating the wear resistance of ceramic materials under severe contact stresses simulating edge loading in prosthetic hip bearings. Simply shaped test specimens - a cylinder and a spheroid - were designed as surrogates for an edge-loaded, head/liner implant pair. Equivalency of the simpler specimens was assured in the sense that their theoretical contact dimensions and pressures were identical, according to Hertzian contact theory, to those of the head/liner pair. The surrogates were fabricated in three ceramic materials: Al2 O3 , zirconia-toughened alumina (ZTA), and ZrO2 . They were mated in three different material pairs and reciprocated under a 200 N normal contact force for 1000-2000 cycles, which created small (material pairs were ranked by their wear resistance, quantified by the volume of abraded material measured using an interferometer. Similar tests were performed on edge-loaded hip implants in the same material pairs. The surrogates replicated the wear rankings of their full-scale implant counterparts and mimicked their friction force trends. The results show that a proxy test using simple test specimens can validly rank the wear performance of ceramic materials under severe, edge-loading contact stresses, while replicating the beginning stage of edge-loading wear. This simple wear test is therefore potentially useful for screening and ranking new, prospective materials early in their development, to produce optimized candidates for more complicated full-scale hip simulator wear tests. Copyright © 2013 Wiley Periodicals, Inc.

Wear mechanisms of Al2O3/TiC/Mo/Ni ceramic wire-drawing dies

International Nuclear Information System (INIS)

Deng Jianxin; Yang Xuefeng; Wang Jinghai

2006-01-01

Al 2 O 3 /TiC/Mo/Ni ceramic composites were produced by hot-pressing for the use of wire drawing dies. The fundamental properties of these ceramic die materials were examined. Wire drawing tests were carried out on the 65Mn steel wire with these ceramic dies. Finite element method (FEM) was used as a means of numerically evaluating stress and its distribution inside the ceramic drawing dies. Worn bore surfaces of the ceramic drawing dies were examined by scanning electron microscopy (SEM). The wear mechanisms of the ceramic drawing dies were investigated. Detailed observations and analyses of the die wear surface have revealed that the most common failure of the ceramic drawing die is the wear at its approach zone. FEM analysis showed that the compressive stresses on both sides of the corners at the approach zone are higher than those of other parts of the ceramic drawing die. Abrasive and adhesive wear were found to be the predominant wear mechanisms through the whole approach zone owing to the greater compressive stresses. Examination of the center bore surface at the die bearing zone of the ceramic drawing dies demonstrated that the wear occurred by light abrasive, no adhesion wear was observed

A study on wear resistance and microcrack of the Ti3Al/TiAl + TiC ceramic layer deposited by laser cladding on Ti-6Al-4V alloy

International Nuclear Information System (INIS)

Li Jianing; Chen Chuanzhong; Squartini, Tiziano; He Qingshan

2010-01-01

Laser cladding of the Al + TiC alloy powder on Ti-6Al-4V alloy can form the Ti 3 Al/TiAl + TiC ceramic layer. In this study, TiC particle-dispersed Ti 3 Al/TiAl matrix ceramic layer on the Ti-6Al-4V alloy by laser cladding has been researched by means of X-ray diffraction, scanning electron microscope, electron probe micro-analyzer, energy dispersive spectrometer. The main difference from the earlier reports is that Ti 3 Al/TiAl has been chosen as the matrix of the composite coating. The wear resistance of the Al + 30 wt.% TiC and the Al + 40 wt.% TiC cladding layer was approximately 2 times greater than that of the Ti-6Al-4V substrate due to the reinforcement of the Ti 3 Al/TiAl + TiC hard phases. However, when the TiC mass percent was above 40 wt.%, the thermal stress value was greater than the materials yield strength limit in the ceramic layer, the microcrack was present and its wear resistance decreased.

In vitro wear of four ceramic materials and human enamel on enamel antagonist.

Science.gov (United States)

Nakashima, Jun; Taira, Yohsuke; Sawase, Takashi

2016-06-01

The purpose of the present study was to evaluate the wear of four different ceramics and human enamel. The ceramics used were lithium disilicate glass (e.max Press), leucite-reinforced glass (GN-Ceram), yttria-stabilized zirconia (Aadva Zr), and feldspathic porcelain (Porcelain AAA). Hemispherical styli were fabricated with these ceramics and with tooth enamel. Flattened enamel was used for antagonistic specimens. After 100,000 wear cycles of a two-body wear test, the height and volume losses of the styli and enamel antagonists were determined. The mean and standard deviation for eight specimens were calculated and statistically analyzed using a non-parametric (Steel-Dwass) test (α = 0.05). GN-Ceram exhibited greater stylus height and volume losses than did Porcelain AAA. E.max Press, Porcelain AAA, and enamel styli showed no significant differences, and Aadva Zr exhibited the smallest stylus height and volume losses. The wear of the enamel antagonist was not significantly different among GN-Ceram, e.max Press, Porcelain AAA, and enamel styli. Aadva Zr resulted in significantly lower wear values of the enamel antagonist than did GN-Ceram, Porcelain AAA, and enamel styli. In conclusion, leucite-reinforced glass, lithium disilicate glass, and feldspathic porcelain showed wear values closer to those for human enamel than did yttria-stabilized zirconia. © 2016 Eur J Oral Sci.

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.

Wear properties of alumina/zirconia composite ceramics for joint prostheses measured with an end-face apparatus.

Science.gov (United States)

Morita, Yusuke; Nakata, Kenichi; Kim, Yoon-Ho; Sekino, Tohru; Niihara, Koichi; Ikeuchi, Ken

2004-01-01

While only alumina is applied to all-ceramic joint prostheses at present, a stronger ceramic is required to prevent fracture and chipping due to impingement and stress concentration. Zirconia could be a potential substitute for alumina because it has high strength and fracture toughness. However, the wear of zirconia/zirconia combination is too high for clinical use. Although some investigations on composite ceramics revealed that mixing of different ceramics was able to improve the mechanical properties of ceramics, there are few reports about wear properties of composite ceramics for joint prosthesis. Since acetabular cup and femoral head of artificial hip joint are finished precisely, they indicate high geometric conformity. Therefore, wear test under flat contact was carried out with an end-face wear testing apparatus for four kinds of ceramics: alumina monolith, zirconia monolith, alumina-based composite ceramic, and zirconia based composite ceramic. Mean contact pressure was 10 MPa and sliding velocity was 40 mm/s. The wear test continued for 72 hours and total sliding distance was 10 km. After the test, the wear factor was calculated. Worn surfaces were observed with a scanning electron micrograph (SEM). The results of this wear test show that the wear factors of the both composite ceramics are similarly low and their mechanical properties are much better than those of the alumina monolith and the zirconia monolith. According to these results, it is predicted that joint prostheses of the composite ceramics are safer against break down and have longer lifetime compared with alumina/alumina joint prostheses.

Abrasive wear behaviour of bio-active glass ceramics containing ...

Indian Academy of Sciences (India)

In this study, abrasive wear behaviour of bio-active glass ceramic materials produced with two different processes is studied. Hot pressing process and conventional casting and controlled crystallization process were used to produce bio-active ceramics. Fracture toughness of studied material was calculated by fracture ...

High temperature resistant cermet and ceramic compositions

Science.gov (United States)

Phillips, W. M. (Inventor)

1978-01-01

Cermet compositions having high temperature oxidation resistance, high hardness and high abrasion and wear resistance, and particularly adapted for production of high temperature resistant cermet insulator bodies are presented. The compositions are comprised of a sintered body of particles of a high temperature resistant metal or metal alloy, preferably molybdenum or tungsten particles, dispersed in and bonded to a solid solution formed of aluminum oxide and silicon nitride, and particularly a ternary solid solution formed of a mixture of aluminum oxide, silicon nitride and aluminum nitride. Also disclosed are novel ceramic compositions comprising a sintered solid solution of aluminum oxide, silicon nitride and aluminum nitride.

Wear of MgO-CaO-SiO2-P2O5-F-Based Glass Ceramics Compared to Selected Dental Ceramics

Directory of Open Access Journals (Sweden)

Jongee Park

2007-01-01

Full Text Available Wear of a glass-ceramic produced through controlled crystallization of a glass in the MgO-CaO-SiO2-P2O5-F system has been evaluated and compared to various commercial dental ceramics including IPS Empress 2, Cergo Pressable Ceramic, Cerco Ceram, and Super porcelain EX-3. Wear tests were performed in accord with the ASTM G99 for wear testing with a pin-on-disk apparatus. The friction coefficient and specific wear rate of the materials investigated were determined at a load of 10 N and at ambient laboratory conditions. Microhardness of the materials was also measured to elucidate the appropriateness of these materials for dental applications.

Erosion resistance and adhesion of composite metal/ceramic coatings produced by plasma spraying

International Nuclear Information System (INIS)

Ramm, D.A.J.; Hutchings, I.M.; Clyne, T.W.

1993-01-01

Ceramic coatings can exhibit greater erosion resistance than most metallic coatings. Such coatings are conveniently produced by thermal spraying. Unfortunately, thermally sprayed ceramic coatings often exhibit poor adhesion, partly as a consequence of the development of residual stresses during spraying and subsequent cooling. Composite coatings have been studied using aluminium/alumina deposits on steel substrates. The incorporation of ceramics within a ductile matrix has potential for sharply reducing the erosive wear at high erodent impact angles, whilst retaining the good erosion resistance of ceramics at low angles. It is shown that the proportion of metal and ceramic at the free surface can be specified so as to optimise the erosion resistance. Experiments have also been carried out on the resistance of the coatings to debonding during four-point bending of the coated substrate. Progress is being made towards the tailoring of composition profiles in graded coatings so as to optimise the combination of erosion resistance and adhesion. (orig.)

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.

A study on wear resistance and microcrack of the Ti{sub 3}Al/TiAl + TiC ceramic layer deposited by laser cladding on Ti-6Al-4V alloy

Energy Technology Data Exchange (ETDEWEB)

Li Jianing, E-mail: ljnljn1022@163.com [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Department of Materials Science, Shandong University, Jing Shi Road 17923, Jinan 250061, Shandong (China); Chen Chuanzhong [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Department of Materials Science, Shandong University, Jing Shi Road 17923, Jinan 250061, Shandong (China); Squartini, Tiziano [INFM-Department of Physics, Siena University, Siena 53100 (Italy); He Qingshan [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Department of Materials Science, Shandong University, Jing Shi Road 17923, Jinan 250061, Shandong (China)

2010-12-15

Laser cladding of the Al + TiC alloy powder on Ti-6Al-4V alloy can form the Ti{sub 3}Al/TiAl + TiC ceramic layer. In this study, TiC particle-dispersed Ti{sub 3}Al/TiAl matrix ceramic layer on the Ti-6Al-4V alloy by laser cladding has been researched by means of X-ray diffraction, scanning electron microscope, electron probe micro-analyzer, energy dispersive spectrometer. The main difference from the earlier reports is that Ti{sub 3}Al/TiAl has been chosen as the matrix of the composite coating. The wear resistance of the Al + 30 wt.% TiC and the Al + 40 wt.% TiC cladding layer was approximately 2 times greater than that of the Ti-6Al-4V substrate due to the reinforcement of the Ti{sub 3}Al/TiAl + TiC hard phases. However, when the TiC mass percent was above 40 wt.%, the thermal stress value was greater than the materials yield strength limit in the ceramic layer, the microcrack was present and its wear resistance decreased.

Wear and creep of highly crosslinked polyethylene against cobalt chrome and ceramic femoral heads.

Science.gov (United States)

Galvin, A L; Jennings, L M; Tipper, J L; Ingham, E; Fisher, J

2010-10-01

The wear and creep characteristics of highly crosslinked ultrahigh-molecular-weight polyethylene (UHMWPE) articulating against large-diameter (36mm) ceramic and cobalt chrome femoral heads have been investigated in a physiological anatomical hip joint simulator for 10 million cycles. The crosslinked UHMWPE/ceramic combination showed higher volume deformation due to creep plus wear during the first 2 million cycles, and a steady-state wear rate 40 per cent lower than that of the crosslinked UHMWPE/cobalt chrome combination. Wear particles were isolated and characterized from the hip simulator lubricants. The wear particles were similar in size and morphology for both head materials. The particle isolation methodology used could not detect a statistically significant difference between the particles produced by the cobalt chrome and alumina ceramic femoral heads.

Wear-dependent specific coefficients in a mechanistic model for turning of nickel-based superalloy with ceramic tools

Science.gov (United States)

López de Lacalle, Luis Norberto; Urbicain Pelayo, Gorka; Fernández-Valdivielso, Asier; Alvarez, Alvaro; González, Haizea

2017-09-01

Difficult to cut materials such as nickel and titanium alloys are used in the aeronautical industry, the former alloys due to its heat-resistant behavior and the latter for the low weight - high strength ratio. Ceramic tools made out alumina with reinforce SiC whiskers are a choice in turning for roughing and semifinishing workpiece stages. Wear rate is high in the machining of these alloys, and consequently cutting forces tends to increase along one operation. This paper establishes the cutting force relation between work-piece and tool in the turning of such difficult-to-cut alloys by means of a mechanistic cutting force model that considers the tool wear effect. The cutting force model demonstrates the force sensitivity to the cutting engagement parameters (ap, f) when using ceramic inserts and wear is considered. Wear is introduced through a cutting time factor, being useful in real conditions taking into account that wear quickly appears in alloys machining. A good accuracy in the cutting force model coefficients is the key issue for an accurate prediction of turning forces, which could be used as criteria for tool replacement or as input for chatter or other models.

Ultrafine Ceramic Grains Embedded in Metallic Glass Matrix: Achieving Superior Wear Resistance via Increase in Both Hardness and Toughness.

Science.gov (United States)

Yang, Lina; Wen, Mao; Dai, Xuan; Cheng, Gang; Zhang, Kan

2018-05-09

As structural materials, crystalline or metallic glass materials have attracted scientific and practical interests. However, some mechanisms involving critical size and shear bands have adverse effects on their mechanical properties. Here, we counter these two effects by introducing a special structure with ultrafine ceramic grains (with a diameter of ∼2.0 nm) embedded into a metallic glass matrix, wherein the grains are mainly composed of a Ta-W-N solid solution structure in nature, surrounded by a W-based amorphous matrix that contains Ta and N atoms. Such a structure is in situ formed during preparation, which combines the merits of both phases to achieve simultaneous increase in hardness and toughness relative to references (pure TaN and W) and thus superior wear resistance. Even more remarkable, a favorable variation of increased hardness but reduced elasticity modulus can be induced by this structure. Intrinsically, ultrafine ceramic grains (free of dislocations), embedded in the metallic glass matrix, could prevent shear band propagation within the glass matrix and further improve the hardness of the matrix material. In return, such glass matrix allows for stiffness neutralization and structural relaxation to reduce the elasticity modulus of ceramic grains. This study will offer a new guidance to fabricate ultrahigh-performance metal-based composites.

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.

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

International Nuclear Information System (INIS)

Samuel, Sonia; Nag, Soumya; Scharf, Thomas W.; Banerjee, Rajarshi

2008-01-01

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

Microstructure and wear behavior of laser cladding VC–Cr7C3 ceramic coating on steel substrate

International Nuclear Information System (INIS)

Wu, Qianlin; Li, Wenge; Zhong, Ning; Gang, Wu; Haishan, Wang

2013-01-01

Highlights: ► The VC–Cr 7 C 3 coating on steel substrate was in situ produced by laser cladding. ► The distribution of VC–Cr 7 C 3 phase decreased gradually from the top of the coating. ► The laser cladding achieved a high hardness of the order of 1000 HV. ► The wear resistance of the coating was 4 times that of the steel substrate. - Abstract: To enhance the wear resistance of mechanical components, laser cladding has been applied to deposit in situ VC–Cr 7 C 3 ceramic coating on steel substrate using a pre-placed powder consisting of vanadium, carbon and high-carbon ferrochrome. The laser cladding samples were subjected to various microstructure examinations, microhardness and wear tests. The results showed that defect-free coating with metallurgical joint to the steel substrate was obtained. The quantity of VC–Cr 7 C 3 particles gradually increased from the bottom to the top of the coating. The VC particles in nanometer were observed within the coating. Average hardness of the coating up to 1050 HV was significantly higher than that of the substrate 150 HV. Wear tests indicated the wear resistance of the clad coating was 4 times that of the steel substrate

Wear of human enamel opposing monolithic zirconia, glass ceramic, and composite resin: an in vitro study.

Science.gov (United States)

Sripetchdanond, Jeerapa; Leevailoj, Chalermpol

2014-11-01

Demand is increasing for ceramic and composite resin posterior restorations. However, ceramics are recognized for their high abrasiveness to opposing dental structure. The purpose of this study was to investigate the wear of enamel as opposed to dental ceramics and composite resin. Twenty-four test specimens (antagonists), 6 each of monolithic zirconia, glass ceramic, composite resin, and enamel, were prepared into cylindrical rods. Enamel specimens were prepared from 24 extracted human permanent molar teeth. Enamel specimens were abraded against each type of antagonist with a pin-on-disk wear tester under a constant load of 25 N at 20 rpm for 4800 cycles. The maximum depth of wear (Dmax), mean depth of wear (Da), and mean surface roughness (Ra) of the enamel specimens were measured with a profilometer. All data were statistically analyzed by 1-way ANOVA, followed by the Tukey test (α=.05). A paired t test was used to compare the Ra of enamel at baseline and after testing. The wear of both the enamel and antagonists was evaluated qualitatively with scanning electron microscopic images. No significant differences were found in enamel wear depth (Dmax, Da) between monolithic zirconia (2.17 ±0.80, 1.83 ±0.75 μm) and composite resin (1.70 ±0.92, 1.37 ±0.81 μm) or between glass ceramic (8.54 ±2.31, 7.32 ±2.06 μm) and enamel (10.72 ±6.31, 8.81 ±5.16 μm). Significant differences were found when the enamel wear depth caused by monolithic zirconia and composite resin was compared with that of glass ceramic and enamel (Pglass ceramic, and enamel (Pglass ceramic and enamel. All test materials except composite resin similarly increased the enamel surface roughness after wear testing. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Influence of full-contour zirconia surface roughness on wear of glass-ceramics.

Science.gov (United States)

Luangruangrong, Palika; Cook, N Blaine; Sabrah, Alaa H; Hara, Anderson T; Bottino, Marco C

2014-04-01

The purpose of this study was to evaluate the influence of full-contour (Y-TZP) zirconia surface roughness (glazed vs. as-machined) on the wear behavior of glass-ceramics. Thirty-two full contour Y-TZP (Diazir®) specimens (hereafter referred to as zirconia sliders) (ϕ = 2 mm, 1.5 mm in height) were fabricated using CAD/CAM and sintered according to the manufacturer's instructions. Zirconia sliders were embedded in brass holders using acrylic resin and then randomly assigned (n = 16) according to the surface treatment received, that is, as-machined or glazed. Glass-ceramic antagonists, Empress/EMP and e.max/EX, were cut into tabs (13 × 13 × 2 mm(3) ), wet-finished, and similarly embedded in brass holders. Two-body pin-on-disk wear testing was performed at 1.2 Hz for 25,000 cycles under a 3 kg load. Noncontact profilometry was used to measure antagonist height (μm) and volume loss (mm(3) ). Qualitative data of the zirconia testing surfaces and wear tracks were obtained using SEM. Statistics were performed using ANOVA with a significance level of 0.05. As-machined yielded significantly higher mean roughness values (Ra = 0.83 μm, Rq = 1.09 μm) than glazed zirconia (Ra = 0.53 μm, Rq = 0.78 μm). Regarding glass-ceramic antagonist loss, as-machined zirconia caused significantly less mean height and volume loss (68.4 μm, 7.6 mm(3) ) for EMP than the glazed group (84.9 μm, 9.9 mm(3) ), while no significant differences were found for EX. Moreover, EMP showed significantly lower mean height and volume loss than EX (p glass-ceramics tested. e.max wear was not affected by zirconia surface roughness; however, Empress wear was greater when opposing glazed zirconia. Overall, surface glazing on full-contour zirconia did not minimize glass-ceramic wear when compared with as-machined zirconia. © 2013 by the American College of Prosthodontists.

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.

High temperature resistant cermet and ceramic compositions. [for thermal resistant insulators and refractory coatings

Science.gov (United States)

Phillips, W. M. (Inventor)

1978-01-01

High temperature oxidation resistance, high hardness and high abrasion and wear resistance are properties of cermet compositions particularly to provide high temperature resistant refractory coatings on metal substrates, for use as electrical insulation seals for thermionic converters. The compositions comprise a sintered body of particles of a high temperature resistant metal or metal alloy, preferably molybdenum or tungsten particles, dispersed in and bonded to a solid solution formed of aluminum oxide and silicon nitride, and particularly a ternary solid solution formed of a mixture of aluminum oxide, silicon nitride and aluminum nitride. Ceramic compositions comprising a sintered solid solution of aluminum oxide, silicon nitride and aluminum nitride are also described.

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.

The friction wear of electrolytic composite coatings

International Nuclear Information System (INIS)

Starosta, R.

2002-01-01

The article presents the results of investigation of wear of galvanic composite coatings Ni-Al 2 O 3 and Ni-41%Fe-Al 2 O 3 . The diameter of small parts of aluminium oxide received 0.5; 3; 5 μm. Investigations of friction sliding were effected on PT3 device at Technical University of Gdansk. Counter sample constituted a funnel made of steel NC6 (750 HV). Increase of wear coatings together with the rise of iron content in matrix is observed. The rise of sizes of ceramic particles caused decrease of wear of composite coatings, but rise of steel funnel wear. The friction coefficient increased after ceramic particle s were built in coatings. The best wear resistance characterized Ni-41%Fe-Al 2 O 3 coatings containing 2.2x10 6 mm -2 ceramic particles. (author)

Advancements in all-ceramics for dental restorations and their effect on the wear of opposing dentition

Science.gov (United States)

Rashid, Haroon; Sheikh, Zeeshan; Misbahuddin, Syed; Kazmi, Murtaza Raza; Qureshi, Sameer; Uddin, Muhammad Zuhaib

2016-01-01

Tooth wear is a process that is usually a result of tooth to tooth and/or tooth and restoration contact. The process of wear essentially becomes accelerated by the introduction of restorations inside the oral cavity, especially in case of opposing ceramic restorations. The newest materials have vastly contributed toward the interest in esthetic dental restorations and have been extensively studied in laboratories. However, despite the recent technological advancements, there has not been a valid in vivo method of evaluation involving clinical wear caused due to ceramics upon restored teeth and natural dentition. The aim of this paper is to review the latest advancements in all-ceramic materials, and their effect on the wear of opposing dentition. The descriptive review has been written after a thorough MEDLINE/PubMed search by the authors. It is imperative that clinicians are aware of recent advancements and that they should always consider the type of ceramic restorative materials used to maintain a stable occlusal relation. The ceramic restorations should be adequately finished and polished after the chair-side adjustment process of occlusal surfaces. PMID:28042280

Wear behavior of pressable lithium disilicate glass ceramic.

Science.gov (United States)

Peng, Zhongxiao; Izzat Abdul Rahman, Muhammad; Zhang, Yu; Yin, Ling

2016-07-01

This article reports effects of surface preparation and contact loads on abrasive wear properties of highly aesthetic and high-strength pressable lithium disilicate glass-ceramics (LDGC). Abrasive wear testing was performed using a pin-on-disk device in which LDGC disks prepared with different surface finishes were against alumina pins at different contact loads. Coefficients of friction and wear volumes were measured as functions of initial surface finishes and contact loads. Wear-induced surface morphology changes in both LDGC disks and alumina pins were characterized using three-dimensional laser scanning microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The results show that initial surface finishes of LDGC specimens and contact loads significantly affected the friction coefficients, wear volumes and wear-induced surface roughness changes of the material. Both wear volumes and friction coefficients of LDGC increased as the load increased while surface roughness effects were complicated. For rough LDGC surfaces, three-body wear was dominant while for fine LDGC surfaces, two-body abrasive wear played a key role. Delamination, plastic deformation, and brittle fracture were observed on worn LDGC surfaces. The adhesion of LDGC matrix materials to alumina pins was also discovered. This research has advanced our understanding of the abrasive wear behavior of LDGC and will provide guidelines for better utilization and preparation of the material for long-term success in dental restorations. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 968-978, 2016. © 2015 Wiley Periodicals, Inc.

Wear resistant performance of highly cross-linked and annealed ultra-high molecular weight polyethylene against ceramic heads in total hip arthroplasty.

Science.gov (United States)

Sato, Taishi; Nakashima, Yasuharu; Akiyama, Mio; Yamamoto, Takuaki; Mawatari, Taro; Itokawa, Takashi; Ohishi, Masanobu; Motomura, Goro; Hirata, Masanobu; Iwamoto, Yukihide

2012-12-01

The purpose of this study was to examine the effects of ceramic femoral head material, size, and implantation periods on the wear of annealed, cross-linked ultra-high molecular weight polyethylene (UHMWPE) (XLPE) in total hip arthroplasty compared to non-cross-linked conventional UHMWPE (CPE). XLPE was fabricated by cross-linking with 60 kGy irradiation and annealing. Femoral heads made from zirconia and alumina ceramics and cobalt-chrome (CoCr) of 22 or 26 mm diameter were used. In this retrospective cohort study, the femoral head penetration into the cup was measured digitally on radiographs of 367 hips with XLPE and 64 hips with CPE. The average follow-up periods were 6.3 and 11.9 years, respectively. Both XLPE creep and wear rates were significantly lower than those of CPE (0.19 mm vs. 0.44 mm, 0.0001 mm/year vs. 0.09 mm/year, respectively). Zirconia displayed increased wear rates compared to alumina in CPE; however, there was no difference among head materials in XLPE (0.0008, 0.00007, and -0.009 mm/year for zirconia, alumina, and CoCr, respectively). Neither head size or implantation period impacted XLPE wear. In contrast to CPE, XLPE displayed low wear rates surpassing the effects of varying femoral head material, size, implantation period, and patient demographics. Further follow-up is required to determine the long-term clinical performance of the annealed XLPE. Copyright © 2012 Orthopaedic Research Society.

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

Science.gov (United States)

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

2015-05-01

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

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

DEFF Research Database (Denmark)

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

2017-01-01

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

Laser cladding of wear resistant metal matrix composite coatings

International Nuclear Information System (INIS)

Yakovlev, A.; Bertrand, Ph.; Smurov, I.

2004-01-01

A number of coatings with wear-resistant properties as well as with a low friction coefficient are produced by laser cladding. The structure of these coatings is determined by required performance and realized as metal matrix composite (MMC), where solid lubricant serves as a ductile matrix (e.g. CuSn), reinforced by appropriate ceramic phase (e.g. WC/Co). One of the engineered coating with functionally graded material (FGM) structure has a dry friction coefficient 0.12. Coatings were produced by coaxial injection of powder blend into the zone of laser beam action. Metallographic and tribological examinations were carried out confirming the advanced performance of engineered coatings

Wear-dependent specific coefficients in a mechanistic model for turning of nickel-based superalloy with ceramic tools

Directory of Open Access Journals (Sweden)

López de Lacalle Luis Norberto

2017-09-01

Full Text Available Difficult to cut materials such as nickel and titanium alloys are used in the aeronautical industry, the former alloys due to its heat-resistant behavior and the latter for the low weight - high strength ratio. Ceramic tools made out alumina with reinforce SiC whiskers are a choice in turning for roughing and semifinishing workpiece stages. Wear rate is high in the machining of these alloys, and consequently cutting forces tends to increase along one operation.

Influence of electrical resistivity and machining parameters on electrical discharge machining performance of engineering ceramics.

Science.gov (United States)

Ji, Renjie; Liu, Yonghong; Diao, Ruiqiang; Xu, Chenchen; Li, Xiaopeng; Cai, Baoping; Zhang, Yanzhen

2014-01-01

Engineering ceramics have been widely used in modern industry for their excellent physical and mechanical properties, and they are difficult to machine owing to their high hardness and brittleness. Electrical discharge machining (EDM) is the appropriate process for machining engineering ceramics provided they are electrically conducting. However, the electrical resistivity of the popular engineering ceramics is higher, and there has been no research on the relationship between the EDM parameters and the electrical resistivity of the engineering ceramics. This paper investigates the effects of the electrical resistivity and EDM parameters such as tool polarity, pulse interval, and electrode material, on the ZnO/Al2O3 ceramic's EDM performance, in terms of the material removal rate (MRR), electrode wear ratio (EWR), and surface roughness (SR). The results show that the electrical resistivity and the EDM parameters have the great influence on the EDM performance. The ZnO/Al2O3 ceramic with the electrical resistivity up to 3410 Ω·cm can be effectively machined by EDM with the copper electrode, the negative tool polarity, and the shorter pulse interval. Under most machining conditions, the MRR increases, and the SR decreases with the decrease of electrical resistivity. Moreover, the tool polarity, and pulse interval affect the EWR, respectively, and the electrical resistivity and electrode material have a combined effect on the EWR. Furthermore, the EDM performance of ZnO/Al2O3 ceramic with the electrical resistivity higher than 687 Ω·cm is obviously different from that with the electrical resistivity lower than 687 Ω·cm, when the electrode material changes. The microstructure character analysis of the machined ZnO/Al2O3 ceramic surface shows that the ZnO/Al2O3 ceramic is removed by melting, evaporation and thermal spalling, and the material from the working fluid and the graphite electrode can transfer to the workpiece surface during electrical discharge

[Ceramic-on-ceramic bearings in total hip arthroplasty (THA)].

Science.gov (United States)

Sentürk, U; Perka, C

2015-04-01

The main reason for total hip arthroplasty (THA) revision is the wear-related aseptic loosening. Younger and active patients after total joint replacement create high demands, in particular, on the bearings. The progress, especially for alumina ceramic-on-ceramic bearings and mixed ceramics have solved many problems of the past and lead to good in vitro results. Modern ceramics (alumina or mixed ceramics containing alumina) are extremely hard, scratch-resistant, biocompatible, offer a low coefficient of friction, superior lubrication and have the lowest wear rates in comparison to all other bearings in THA. The disadvantage of ceramic is the risk of material failure, i.e., of ceramic fracture. The new generation of mixed ceramics (delta ceramic), has reduced the risk of head fractures to 0.03-0.05 %, but the risk for liner fractures remains unchanged at about 0.02 %. Assuming a non-impinging component implantation, ceramic-on-ceramic bearings have substantial advantages over all other bearings in THA. Due to the superior hardness, ceramic bearings produce less third body wear and are virtually impervious to damage from instruments during the implantation process. A specific complication for ceramic-on-ceramic bearings is "squeaking". The high rate of reported squeaking (0.45 to 10.7 %) highlights the importance of precise implant positioning and the stem and patient selection. With precise implant positioning this problem is rare with many implant designs and without clinical relevance. The improved tribology and the presumable resulting implant longevity make ceramic-on-ceramic the bearing of choice for young and active patients. Georg Thieme Verlag KG Stuttgart · New York.

Ceramic on ceramic arthroplasty of the hip: new materials confirm appropriate use in young patients.

Science.gov (United States)

Sentuerk, U; von Roth, P; Perka, C

2016-01-01

The leading indication for revision total hip arthroplasty (THA) remains aseptic loosening owing to wear. The younger, more active patients currently undergoing THA present unprecedented demands on the bearings. Ceramic-on-ceramic (CoC) bearings have consistently shown the lowest rates of wear. The recent advances, especially involving alumina/zirconia composite ceramic, have led to substantial improvements and good results in vitro. Alumina/zirconia composite ceramics are extremely hard, scratch resistant and biocompatible. They offer a low co-efficient of friction and superior lubrication and lower rates of wear compared with other bearings. The major disadvantage is the risk of fracture of the ceramic. The new composite ceramic has reduced the risk of fracture of the femoral head to 0.002%. The risk of fracture of the liner is slightly higher (0.02%). Assuming that the components are introduced without impingement, CoC bearings have major advantages over other bearings. Owing to the superior hardness, they produce less third body wear and are less vulnerable to intra-operative damage. The improved tribology means that CoC bearings are an excellent choice for young, active patients requiring THA. ©2016 The British Editorial Society of Bone & Joint Surgery.

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

Directory of Open Access Journals (Sweden)

O. Cuevas Mata

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

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.

Laser beam joining of non-oxidic ceramics for ultra high temperature resistant joints

International Nuclear Information System (INIS)

Lippmann, W.; Knorr, J.; Wolf, R.; Reinecke, A.M.; Rasper, R.

2004-01-01

The excellent technical properties of silicon carbide (SiC) and silicon nitride (Si 3 N 4 ) ceramics, such as resistance to extreme temperatures, oxidation, mechanical wear, aggressive chemical substances and radioactive radiation and also its high thermal conductivity and good temperature-shock resistance, make these ceramics ideally suited for use in the field of nuclear technology. However, their practical use has been limited so far because of the unavailability of effective joining techniques for these ceramics, especially for high temperature applications. A new joining technology (CERALINK registered ) has been developed in a network project which allowed high temperature resistant and vacuum-tight joining of SiC or Si 3 N 4 ceramics. A power laser is used as heat source, which makes it possible to join ceramic components in free atmosphere in combination with a pure oxidic braze filler. As no furnace is necessary, there are no limitations on the component dimensions by the furnace-geometry. During the joining process, the heated area can be limited to the seam area so that this technology can also be used to encapsulate materials with a low melting point. The seam has a high mechanical strength, it is resistant to a wide range of chemicals and radiation and it is also vacuum-tight. The temperature resistance can be varied by variation of the braze filler composition - usually between 1,400 C and >1,600 C. Beside the optimum filler it is also important to select the suitable laser wavelength. The paper will demonstrate the influence of different wave lengths, i. e. various laser types, on the seam quality. Examples are chosen to illustrate the strengths and limitations of the new technology

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.

Tough ceramics prolong the life of valves, pumps and well tools; Seig keramikk forlenger livet til ventiler, pumper og broennverktoey

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-07-01

Advanced ceramic materials, developed by Dynamic-Ceramic in the UK, are playing a chief role in improving the efficiency of components of oil and gas plants around the world. Transformation toughened zirconia ceramics are more resistant than metals to wear, corrosion, erosion and heat. On oil installations, they are typically used in the wearing parts of MWD (measuring while drilling) and LWD (logging while drilling) equipment, valve plugs, spindles, cages etc. For example, catalyzer tubes made of wear-resistant Technox(TM) last ten times as long as fire-resisting sleeves that are used for the same purpose.

DEVELOPMENT OF WEAR RESISTANT COATINGS FORMED BY PLASMA SPRAYING OF ALLOY Ni–Fe–Cr–Si–B–C SYSTEM REINFORCED WITH CERAMICS Al2O3

Directory of Open Access Journals (Sweden)

A. S. Kalinichenko

2016-01-01

Full Text Available . Creating a functionally oriented, including nanostructured, anti-friction materials and coatings with qualitatively new complex of service properties is an important scientific and practical problem. In particular, for the cable industry it is urgent task of ensuring the high performance properties of fast deteriorating stretching and supporting rollers. Working surfaces of these parts operate under practically dry friction conditions with constantly updated material of stretching wire. Plasma spraying is one of the widely used methods of surface engineering to create wear resistant coatings and which is characterized with process flexibility and the ability to create coatings using various materials and alloys including composite ones. The installation UPU-3D with the PP-25 plasma torch was used for plasma spraying. The thickness of the sprayed layer was 0.8–1.1 mm. As a material for the deposition of composite coatings a powder mixture of self-fluxing nickel alloy PG-HN80SR4 (system Ni–Fe–Cr–Si–B–C and a neutral oxide ceramics Al2O3 was used. The amount of ceramics varied from 15 to 33 %. This ceramic oxide was selected due to the desire to reduce coatings’ costs while providing high durability. Carried out phase and microstructural studies have shown when ceramics was added in an amount more than 20 % a formation of conglomerates formed by not melted alumina particles often was observed. These conglomerates serve as crack formation centers in the coating. The phase composition of the coatings practically does not depend on the content of ceramics compounds. Tribological tests have shown that the best results were obtained when the content of the oxide ceramic in the coating was in the range from 15 to 20 %.

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 intensity and surface roughness of microhybrid composite and ceramic occlusal veneers on premolars after the thermocycling and cyclic mechanical loading tests].

Science.gov (United States)

Zhang, H Y; Jiang, T; Cheng, M X; Zhang, Y W

2018-02-18

To evaluate the wear intensity and surface roughness of occlusal veneers on premolars made of microhybrid composite resin or two kinds of ceramics in vitro after the thermocycling and cyclic mechanical loading tests. In the study,24 fresh extracted human premolars without root canal treatment were prepared (cusps reduction of 1.5 mm in thickness to simulate middle to severe tooth wear, the inclinations of cusps were 20°). The prepared teeth were restored with occlusal veneers made of three different materials: microhybrid composite, heat-pressed lithium disilicate ceramic and computer-aided design/computer-aided manufacturing (CAD/CAM) lithium disilicate ceramic in the thickness of 1.5 mm. The occlusal veneers were cemented with resin cement. The specimens were fatigued using the thermocycling and cyclic mechanical loading tests after being stored in water for 72 h. The wear of specimens was measured using gypsum replicas and 3D laser scanner before and after the thermocycling and cyclic mechanical loading tests and the mean lost distance (mm) was used to indicate the level of wear. The surfaces of occlusal contact area were observed and the surface roughness was recorded using 3D laser scanning confocal microscope before and after the fatigue test. Differences between the groups were compared using ONE-way ANOVA(Pcomposite group, heat-pressed lithium disilicate ceramic group, and CAD/CAM lithium disilicate ceramic group was (-0.13±0.03) mm, (-0.05±0.01) mm and (-0.05±0.01) mm, the wear of microhybrid composite was significantly higher than the two ceramic groups(Pcomposite was significantly higher than the two ceramic groups(Pcomposite(P=0.005) and CAD/CAM lithium disilicate ceramic (P=0.010). From the view of wear speed, microhybrid composite was significantly higher than the two kinds of ceramics, but it was similar to enamel when the opposing tooth was natural. The surface roughness before the themocycling and cyclic mechanical loading test of microhybrid

Ceramic cutting tools materials, development and performance

CERN Document Server

Whitney, E Dow

1994-01-01

Interest in ceramics as a high speed cutting tool material is based primarily on favorable material properties. As a class of materials, ceramics possess high melting points, excellent hardness and good wear resistance. Unlike most metals, hardness levels in ceramics generally remain high at elevated temperatures which means that cutting tip integrity is relatively unaffected at high cutting speeds. Ceramics are also chemically inert against most workmetals.

Wear Potential of Dental Ceramics and its Relationship with Microhardness and Coefficient of Friction.

Science.gov (United States)

Freddo, Rafael Augusto; Kapczinski, Myriam Pereira; Kinast, Eder Julio; de Souza Junior, Oswaldo Baptista; Rivaldo, Elken Gomes; da Fontoura Frasca, Luis Carlos

2016-10-01

To evaluate, by means of pin-on-disk testing, the wear potential of different dental ceramic systems as it relates to friction parameters, surface finish, and microhardness. Three groups of different ceramic systems (Noritake EX3, Eris, Empress II) with 20 disks each (10 glazed, 10 polished) were used. Vickers microhardness (Hv) was determined with a 200-g load for 30 seconds. Friction coefficients (μ) were determined by pin-on-disk testing (5 N load, 600 seconds, and 120 rpm). Wear patterns were assessed by scanning electron microscopy (SEM). The results were analyzed using one-way ANOVA and Tukey's test, with the significance level set at α = 0.05. The coefficients of friction were as follows: Noritake EX3 0.28 ± 0.12 (polished), 0.33 ± 0.08 (glazed); Empress II 0.38 ± 0.08 (polished), 0.45 ± 0.05 (glazed); Eris 0.49 ± 0.05 (polished), 0.49 ± 0.06 (glazed). Microhardness measurements were as follows: Noritake EX3 530.7 ± 8.7 (polished), 525.9 ± 6.2 (glazed); Empress II 534.1 ± 8 (polished), 534.7 ± 4.5 (glazed); Eris, 511.7 ± 6.5 (polished), 519.5 ± 4.1 (glazed). The polished and glazed Noritake EX3 and polished and glazed Eris specimens showed statistically different friction coefficients. SEM image analysis revealed more surface changes, such as small cracks and grains peeling off, in glazed ceramics. Wear potential may be related to the coefficient of friction in Noritake ceramics, which had a lower coefficient than Eris ceramics. Within-group analysis showed no differences in polished or glazed specimens. The differences observed were not associated with microhardness. © 2015 by the American College of Prosthodontists.

Wear Behavior of Cold Pressed and Sintered Al2O3/TiC/CaF2Al2O3/TiC Laminated Ceramic Composite

Institute of Scientific and Technical Information of China (English)

Xuefeng YANG; Jian CHENG; Peilong SONG; Shouren WANG; Liying YANG; Yanjun WANG; Ken MAO

2013-01-01

A novel laminated Al2O3/TiC/CaF2-Al2O3/TiC sandwich ceramic composite was fabricated through cold pressing and sintering to achieve better anti-wear performance,such as low friction coefficient and low wear rate.Al2O3/TiC/CaF2 and Al2O3/TiC composites were alternatively built layer-by-layer to obtain a sandwich structure.Solid lubricant CaF2 was added evenly into the Al2O3/TiC/CaF2 layer to reduce the friction and wear.Al2O3/TiC ceramic was also cold pressed and sintered for comparison.Friction analysis of the two ceramics was then conducted via a wear-and-tear machine.Worn surface and surface compositions were examined by scanning electron microscopy and energy dispersion spectrum,respectively.Results showed that the laminated Al2O3/TiC/CaF2-Al2O3/TiC sandwich ceramic composite has lower friction coefficient and lower wear rate than those of Al2O3/TiC ceramic alone because of the addition of CaF2 into the laminated Al2O3/TiC/CaF2-Al2O3/TiC sandwich ceramic composite.Under the friction load,the tiny CaF2 particles were scraped from the Al2O3/TiC/CaF2 layer and spread on friction pairs before falling off into micropits.This process formed a smooth,self-lubricating film,which led to better anti-wear properties.Adhesive wear is the main wear mechanism of Al2O3/TiC/CaF2 layer and abrasive wear is the main wear mechanism of Al2O3/TiC layer.

A new production technique for wear resistant ring-hammers

Directory of Open Access Journals (Sweden)

Li Shifeng

2011-11-01

Full Text Available Based on a great number of laboratory experiments, a new technique has been developed for producing wear resistant ring-hammers. In this technology, lost foam casting with iron sand was combined to make mold; a special alloy was used to inoculate the molten steel, and proper heat treatment was used to further improve mechanical properties of wear resistant ring-hammers. The influence of this new production technology on the microstructure and mechanical properties of wear resistant ring-hammers was studied. Results show that iron sand molding, having the inherent characteristic of sand molding, changes the type of metallic compounds, refines crystal grains and increases the fineness of microstructure. Practical experience verified that the properties of the ring-hammers produced with this new technique are as follows: tensile strength (Rm 720 MPa, impact toughness (ak > 210 J•cm-2 and hardness > 200 HB. After water quenching from 1,080℃ (holding for 4 h and tempering at 320℃ for 3 h, the best wear resistance is obtained, and the wear resistance is 1.6 times higher than that of common high manganese ring-hammers.

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

Changing in tool steels wear resistance under electron irradiation

International Nuclear Information System (INIS)

Braginskaya, A.E.; Manin, V.N.; Makedonskij, A.V.; Mel'nikova, N.A.; Pakchanin, L.M.; Petrenko, P.V.

1983-01-01

The tool steels and alloys wear resistance under dry friction after electron irradiation has been studied. Electron irradiation of a wide variety of steels is shown to increase wear resistance. In this case phase composition and lattice parameters changes are observed both in matrix and carbides. The conclusion is drawn that an appreciable increase of steel wear resistance under electron irradiation can be explained both by carbide phase volume gain and changes in it's composition and the formation of carbide phase submicroscopic heterogeneities and, possibly, complexes of defects

Wear resistance of cast iron

Directory of Open Access Journals (Sweden)

S. Pietrowski

2008-10-01

Full Text Available In this paper investigations of abrasive and adhesive wear resistance of different cast iron grades have been presented. Examinations showed, that the most advantageous pair of materials is the cast iron – the hardened steel with low-tempered martensite. It was found, that martensitic nodular cast iron with carbides is the most resistant material.

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.

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-10-15

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

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

International Nuclear Information System (INIS)

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

2015-01-01

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

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

Influence of the metallic matrix ratio on the wear resistance (dry and slurry abrasion) of plasma sprayed cermet (chromia / stainless steel) coatings

Czech Academy of Sciences Publication Activity Database

Ageorges, H.; Ctibor, Pavel; Medarhri, Z.; Touimi, S.; Fauchais, P.

2006-01-01

Roč. 201, č. 5 (2006), s. 2006-2011 ISSN 0257-8972 R&D Projects: GA AV ČR(CZ) 1QS200430560 Institutional research plan: CEZ:AV0Z20430508 Keywords : plasma spraying * composite coating * tribology * hardness * wear * abrasion * chromia/stainless steel Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.559, year: 2006

Surface modification of ceramics. Ceramics no hyomen kaishitsu

Energy Technology Data Exchange (ETDEWEB)

Hioki, T. (Toyota Central Research and Development Labs., Inc., Nagoya (Japan))

1993-07-05

Surface modification of ceramics and some study results using in implantation in surface modification are introduced. The mechanical properties (strength, fracture toughness, flaw resistance) of ceramics was improved and crack was repaired using surface modification by ion implantation. It is predicted that friction and wear properties are considerably affected because the hardness of ceramics is changed by ion implantation. Cementing and metalization are effective as methods for interface modification and the improvement of the adhesion power of the interface between metal and ceramic is their example. It was revealed that the improvement of mechanical properties of ceramics was achieved if appropriate surface modification was carried out. The market of ceramics mechanical parts is still small, therefore, the present situation is that the field of activities for surface modification of ceramics is also narrow. However, it is thought that in future, ceramics use may be promoted surely in the field like medicine and mechatronics. 8 refs., 4 figs.

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 ...

Effect of different dental ceramic systems on the wear of human enamel: An in vitro study.

Science.gov (United States)

Zandparsa, Roya; El Huni, Rabie M; Hirayama, Hiroshi; Johnson, Marc I

2016-02-01

The wear of tooth structure opposing different advanced dental ceramic systems requires investigation. The purpose of this in vitro study was to compare the wear of advanced ceramic systems against human enamel antagonists. Four ceramic systems (IPS e.max Press, IPS e.max CAD, Noritake Super Porcelain EX-3, and LAVA Plus Zirconia) and 1 control group containing human enamel specimens were used in this study (n = 12). All specimens were fabricated as disks 11 mm in diameter and 3 mm thick. The mesiopalatal cusps of the maxillary third molars were prepared to serve as the enamel styluses. All specimens were embedded individually in 25 mm(3) autopolymerizing acrylic resin blocks. Wear was measured with a cyclic loading machine and a newly designed wear simulator. All enamel styluses (cusps) were scanned using the Activity 880 digital scanner (SmartOptics). Data from the base line and follow-up scans were collected and compared with Qualify 2012 3-dimensional (3D) and 2D digital inspection software (Geomagic), which aligned the models and detected the geometric changes and the wear caused by the antagonist specimen. One-way ANOVA was used to analyze the collected data. After 125,000 bidirectional loading cycles, the mean loss of opposing enamel volume for the enamel disks in the control group was 37.08 μm(3), the lowest mean value for IPS e.max Press system was 39.75 μm(3); 40.58 μm(3) for IPS e.max CAD; 45.08 μm(3) for Noritake Super Porcelain EX-3 system; and 48.66 μm(3) for the Lava Plus Zirconia system. No statically significant differences were found among the groups in opposing enamel volume loss (P=.225) or opposing enamel height loss (P=.149). In terms of opposing enamel height loss, Lava Plus Zirconia system showed the lowest mean value of 27.5 μm. The mean value for the IPS e.max CAD system was 27.91 μm; 29.08 μm for the control enamel; 33.25 μm for the IPS e.max Press system; and 34.75 μm for the Noritake Super Porcelain EX-3 system. Within the

Two-body wear rate of CAD/CAM resin blocks and their enamel antagonists.

Science.gov (United States)

Stawarczyk, Bogna; Özcan, Mutlu; Trottmann, Albert; Schmutz, Felix; Roos, Malgorzata; Hämmerle, Christoph

2013-05-01

Computer-aided design and computer-aided manufacturing (CAD/CAM) resins exhibit good mechanical properties and can be used as long-term restorations. The wear rate of such resins and their enamel antagonists is unknown. The purpose of this study was to test and compare the 2-body wear rate of CAD/CAM resin blocks. Wear specimens (N=42, n=6) were made from 5 CAD/CAM resins: ZENO PMMA (ZP), artBloc Temp (AT), Telio CAD (TC), Blanc High-class (HC), CAD-Temp (CT); 1 manually polymerized resin: Integral esthetic press (negative control group, IEP); and 1 glass-ceramic: VITA Mark II (positive control group, VM2). The specimens for the wear resistance were aged in a thermomechanical loading machine (49 N, 1.67 Hz, 5/50°C) with human enamel antagonists. The material loss of all specimens before, during, and after aging was evaluated with a 3DS profilometer. The measured material loss data of all tested groups were statistically evaluated with linear mixed model analysis (a=.05). Manually polymerized resin showed significantly higher material wear (P<.001) than all other tested groups. Glass-ceramic showed significantly lower wear values (P<.001) than CAD/CAM resins ZP, AT, HC, CT, and IES. CAD/CAM resin TC was not significantly different from the positive control group. Glass-ceramic showed the highest enamel wear values (P<.001) of all tested resins. No differences were found in the enamel wear among all resins. The glass-ceramic group showed damage in the form of cracks on the worn enamel surface in 50% of specimens. CAD/CAM resins showed lower wear rates than those conventionally polymerized. Only one CAD/CAM resin, TC, presented material wear values comparable with glass-ceramic. The tested glass-ceramic developed cracks in the enamel antagonist and showed the highest enamel wear values of all other tested groups. Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

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

Directory of Open Access Journals (Sweden)

I. Sudhakar

2015-03-01

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

Comparison of the structure and wear resistance of Al2O3 -13 wt%TiO2 coatings made by GSP and WSP plasma process with two different powders

Czech Academy of Sciences Publication Activity Database

Ageorges, H.; Ctibor, Pavel

2008-01-01

Roč. 202, č. 18 (2008), s. 4362-4368 ISSN 0257-8972 R&D Projects: GA AV ČR 1QS200430560 Institutional research plan: CEZ:AV0Z20430508 Keywords : Alumina * titania * plasma spraying * wear resistance * slurry abrasion Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.860, year: 2008

Influence of ceramic thickness and ceramic materials on fracture resistance of posterior partial coverage restorations.

Science.gov (United States)

Bakeman, E M; Rego, N; Chaiyabutr, Y; Kois, J C

2015-01-01

This study evaluated the influence of ceramic thickness and ceramic materials on fracture resistance of posterior partial coverage ceramic restorations. Forty extracted molars were allocated into four groups (n=10) to test for two variables: 1) the thickness of ceramic (1 mm or 2 mm) and 2) the ceramic materials (a lithium disilicate glass-ceramic [IPS e.max] or leucite-reinforced glass ceramic [IPS Empress]). All ceramic restorations were luted with resin cement (Variolink II) on the prepared teeth. These luted specimens were loaded to failure in a universal testing machine, in the compression mode, with a crosshead speed of 1.0 mm/min. The data were analyzed using two-way analysis of variance and the Tukey Honestly Significantly Different multiple comparison test (α =0.05). The fracture resistance revealed a significant effect for materials (pceramic was not significant (p=0.074), and the interaction between the thickness of ceramic and the materials was not significant (p=0.406). Mean (standard deviation) fracture resistance values were as follows: a 2-mm thickness of a lithium disilicate bonded to tooth structure (2505 [401] N) revealed a significantly higher fracture resistance than did a 1-mm thickness of leucite-reinforced (1569 [452] N) and a 2-mm thickness of leucite-reinforced ceramic bonded to tooth structure (1716 [436] N) (pceramic at 1-mm thickness (2105 [567] N) and at 2-mm thickness. Using a lithium disilicate glass ceramic for partial coverage restoration significantly improved fracture resistance compared to using a leucite-reinforced glass ceramic. The thickness of ceramic had no significant effect on fracture resistance when the ceramics were bonded to the underlying tooth structure.

Wear and Reactivity Studies of Melt infiltrated Ceramic Matrix Composite

Science.gov (United States)

Jarmon, David C.; Ojard, Greg; Brewer, David N.

2013-01-01

As interest grows in the use of ceramic matrix composites (CMCs) for critical gas turbine engine components, the effects of the CMCs interaction with the adjoining structure needs to be understood. A series of CMC/material couples were wear tested in a custom elevated temperature test rig and tested as diffusion couples, to identify interactions. Specifically, melt infiltrated silicon carbide/silicon carbide (MI SiC/SiC) CMC was tested in combination with a nickel-based super alloy, Waspaloy, a thermal barrier coating, Yttria Stabilized Zirconia (YSZ), and a monolithic ceramic, silicon nitride (Si3N4). To make the tests more representative of actual hardware, the surface of the CMC was kept in the as-received state (not machined) with the full surface features/roughness present. Test results include: scanning electron microscope characterization of the surfaces, micro-structural characterization, and microprobe analysis.

Development of wear-resistant coatings for cobalt-base alloys

International Nuclear Information System (INIS)

Cockeram, B.V.

1999-01-01

The level of nuclear plant radiation exposure due to activated cobalt wear debris could potentially be reduced by covering the cobalt-base materials with a wear resistant coating. Laboratory pin-on-disc and rolling contact wear tests were used to evaluate the wear performance of several coatings. Based on the results of these tests, multilayer Cr-nitride coatings and ion nitriding are the most promising approaches

In situ fabrication of blue ceramic coatings on wrought Al Alloy 2024 by plasma electrolytic oxidation

International Nuclear Information System (INIS)

Wang Zhijiang; Nie Xueyuan; Hu, Henry; Hussein, Riyad O.

2012-01-01

In situ formation of ceramic coatings on 2024 Al alloy with a blue color was successfully achieved using a plasma electrolytic oxidation process working at atmospheric pressure. This novel blue ceramic coating overcomes the shortcomings of surface treatments resulting from conventional dyeing processes by depositing organic dyes into the porous structure of anodic film, which has poor resistance to abrasion and rapid fading when exposed to sunlight. X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy were employed to characterize the microstructure of the blue ceramic coating. The fabricated ceramic coating was composed of CoAl 2 O 4 , α-Al 2 O 3 , and γ-Al 2 O 3. By controlling the working parameters, the distribution of the CoAl 2 O 4 phase on the surface can be adjusted, and plays a key role in the appearance of the coating. Electrochemical testing, thermal cycling method, and pin-on-disk sliding wear testing were employed to evaluate corrosion, thermal cycling, and wear resistance of the ceramic coatings. The results indicate that the blue ceramic coating has a similar polarization resistance to that of conventional anodic film and can significantly enhance the corrosion resistance of aluminum alloy. There are no destructive horizontal cracks observed within the blue ceramic coating when subjected to 120 times of thermal cycling, which heats the samples up to 573 K and followed by submersion in water at room temperature for 10 min. Compared with the aluminum substrate as well as a conventional anodic film coated aluminum sample, the wear resistance of the blue ceramic coating coated sample was significantly increased while the coefficient of friction was decreased from 0.34 to 0.14.

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

CERN Document Server

American Society for Testing and Materials. Philadelphia

2003-01-01

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

Frictional Resistance of Three Types of Ceramic Brackets

Directory of Open Access Journals (Sweden)

Claire L Williams

2014-01-01

Full Text Available Objectives: To investigate the static frictional resistance at the bracket/archwire interface in two recently introduced bracket systems and compare them to conventional ceramic and conventional metal bracket systems. Three variables were considered including the bracket system, archwire type and archwire angulation. Material and Methods: Four bracket systems were tested in vitro: Self ligating ceramic, ceramic with metal slot and module, conventional ceramic with module and conventional metal with module. A specially constructed jig and an Instron testing machine were used to measure the static frictional resistance for 0.014 inches round and 0.018 x 0.025 inches rectangular stainless steel wires at 0° and 7° angulations. Main outcome measures: static frictional force at the bracket/archwire interface; recorded and measured in units of force (Newtons. Results: Self ligating ceramic and metal slot ceramic bracket systems generated significantly less static frictional resistance than conventional ceramic bracket systems with the wire at both angulations (P < 0.05. Changing the wire from 0.014 round to 0.018 x 0.025 rectangular wire significantly increased frictional forces for metal slot ceramic and conventional metal bracket systems (P < 0.01. Increasing wire angulation significantly increased frictional resistance at the bracket/archwire interface for all four types of bracket systems tested (P < 0.001. Conclusions: Compared to conventional ceramic, self ligating ceramic and metal slot ceramic bracket systems should give improved clinical performance, matching that of conventional metal brackets.

Nanocrystalline, superhard, ductile ceramic coatings for roller-cone bit bearings

Energy Technology Data Exchange (ETDEWEB)

Namavar, F.; Colter, P.; Karimy, H. [Spire Corp., Bedford, MA (United States)] [and others

1997-12-31

The established method for construction of roller bits utilizes carburized steel, frequently with inserted metal bearing surfaces. This construction provides the necessary surface hardness while maintaining other desirable properties in the core. Protective coatings are a logical development where enhanced hardness, wear resistance, corrosion resistance, and surface properties are required. The wear properties of geothermal roller-cone bit bearings could be further improved by application of protective ceramic hard coatings consisting of nanometer-sized crystallites. Nanocrystalline protective coatings provide the required combination of hardness and toughness which has not been available thus far using traditional ceramics having larger grains. Increased durability of roller-cone bit bearings will ultimately reduce the cost of drilling geothermal wells through increased durability.

Wear Characteristics of Ceramic Coating Materials by Plasma Spray under the Lubricative Environment

International Nuclear Information System (INIS)

Kim, Chang Ho

2001-02-01

This paper is to investigate the wear behaviors of two types of ceramics, Al 2 O 3 and TiO 2 , by coated plasma thermal spray method under the lubricative environment. The lubricative environments are grease fluids, a general hydraulic fluids, and bearing fluids. The wear testing machine used a pin on disk type. Wear characteristics, which were friction force, friction coefficient and the specific wear rate, according to the lubricative environments were obtained at the four kinds of load, and the sliding velocity is 0.2m/sec. After the wear experiments, the wear surfaces of the each test specimen were observed by a scanning electronic microscope. The obtained results are as follows. : 1. The friction coefficients of TiO 2 coating materials are 0.11 ∼ 0.16 range and those of Al 2 O 3 are 0.24 ∼ 0.39. The friction coefficient of two coating materials is relative to the hardness of these materials. 2. The friction coefficient of TiO 2 coating materials in three lubricative environments is almost same to each other in spite of changing of applied loads. 3. The friction coefficient of Al 2 O 3 coating materials is more large in low load than high load. And the friction coefficient in grease is more large than a general hydraulic and bearing fluids had almost same friction coefficient. 4. The specific wear rate in TiO 2 is greatly increasing according to change the applied loads, but that in Al 2 O 3 is slightly. And the wear in grease is the least among three lubricating environments. 5. On the wear mechanism by SEM image observation, the wear of Al 2 O 3 is adhesive wear and TiO 3 is abrasive wear

The development and testing of ceramic components in piston engines. Final report

Energy Technology Data Exchange (ETDEWEB)

McEntire, B.J. [Norton Co., Northboro, MA (United States). Advanced Ceramics Div.; Willis, R.W.; Southam, R.E. [TRW, Inc., Cleveland, OH (United States)

1994-10-01

Within the past 10--15 years, ceramic hardware has been fabricated and tested in a number of piston engine applications including valves, piston pins, roller followers, tappet shims, and other wear components. It has been shown that, with proper design and installation, ceramics improve performance, fuel economy, and wear and corrosion resistance. These results have been obtained using rig and road tests on both stock and race engines. Selected summaries of these tests are presented in this review paper.

In situ fabrication of blue ceramic coatings on wrought Al Alloy 2024 by plasma electrolytic oxidation

Energy Technology Data Exchange (ETDEWEB)

Wang Zhijiang; Nie Xueyuan; Hu, Henry; Hussein, Riyad O. [Department of Mechanical, Automotive and Materials Engineering, University of Windsor, Windsor, Ontario N9B 3P4 (Canada)

2012-03-15

In situ formation of ceramic coatings on 2024 Al alloy with a blue color was successfully achieved using a plasma electrolytic oxidation process working at atmospheric pressure. This novel blue ceramic coating overcomes the shortcomings of surface treatments resulting from conventional dyeing processes by depositing organic dyes into the porous structure of anodic film, which has poor resistance to abrasion and rapid fading when exposed to sunlight. X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy were employed to characterize the microstructure of the blue ceramic coating. The fabricated ceramic coating was composed of CoAl{sub 2}O{sub 4}, {alpha}-Al{sub 2}O{sub 3}, and {gamma}-Al{sub 2}O{sub 3.} By controlling the working parameters, the distribution of the CoAl{sub 2}O{sub 4} phase on the surface can be adjusted, and plays a key role in the appearance of the coating. Electrochemical testing, thermal cycling method, and pin-on-disk sliding wear testing were employed to evaluate corrosion, thermal cycling, and wear resistance of the ceramic coatings. The results indicate that the blue ceramic coating has a similar polarization resistance to that of conventional anodic film and can significantly enhance the corrosion resistance of aluminum alloy. There are no destructive horizontal cracks observed within the blue ceramic coating when subjected to 120 times of thermal cycling, which heats the samples up to 573 K and followed by submersion in water at room temperature for 10 min. Compared with the aluminum substrate as well as a conventional anodic film coated aluminum sample, the wear resistance of the blue ceramic coating coated sample was significantly increased while the coefficient of friction was decreased from 0.34 to 0.14.

Strength and gas-abrasive wear-resistance of zirconium carbide based cerments

International Nuclear Information System (INIS)

Samsonov, G.V.; Dan'kin, A.A.; Markov, A.A.; Bogomol, I.V.

1976-01-01

Results relating to a study of cermet strength and wear resistance by means of a gas-abrasive flow are presented. It has been found that with a higher amount of the metallic binder (over 25 at.%) in zirconium carbide-based cermets the bending and compression strength and also hardness and wear resistance within the systems ZrC-Nb, ZrC-Mo, ZrC-W become lower. The interrelation of the cermet wear resistance of the various systems and their bending and compression strengths, which, in turn, depend on the electronic structure is shown

Microstructure and wear resistance of in situ porous TiO/Cu composites

Science.gov (United States)

Qin, Qingdong; Huang, Bowei; Li, Wei

2016-07-01

An in situ porous TiO/Cu composite is successfully prepared using powder metallurgy by the reaction of Ti2CO and Cu powder. Morphological examination of the composite shows that the porosity of composites lies in the range between 10.2% and 35.2%. Dry sliding un-lubricated wear tests show that the wear resistance of the composite is higher than that of the Cu-Al alloy ingot. The coefficient of friction test shows that, as the volume fraction of the reinforced phase increases, the coefficient of friction decreases. The wear rate variation trend of the oil-lubricated wear test results is similar to that of the un-lubricated wear test results. The coefficient of friction for oil lubrication is similar for different volume fractions of the reinforced phase. The wear resistance of the composite at a sliding velocity of 200 rpm is slightly larger than that at 50 rpm. The porosity of the composites enhances the high-velocity oil-lubricated sliding wear resistance.

Study on wear resistance of vanadium alloying compacted/vermicular graphite cast iron

International Nuclear Information System (INIS)

Park, Yoon Woo

1987-01-01

Wear resistance of the Compacted/Vermicular graphite cast irons was studied by changing the vanadium content in the cast irons. The results obtained in this work are summarized as follows. 1. When the same amount of vanadium was added to the flake graphite cast iron, spheroidal graphitecast iron and Compacted/Vermicular graphite cast iron, spheroidal graphite cast iron and Compacted/Vermicular graphite cast iron wear resistance decreased in following sequence, that is, flake graphite cast iron> spheroidal graphite cast iron>Compacted/Vermicular graphite cast iron. 2. Addition of vanadium to the Compacted/Vermicular cast iron leaded to a remarkable increase in hardness because it made the amount of pearlite in matrix increase. 3. Addition of vanadium to the compacted/Vermicular graphite cast iron significantly enhanced wear resistance and the maximum resistance was achieved at about 0.36% vanadium. 4. The maximum amount of wear apppeared at sliding speed of about 1.4m/sec and wear mode was considered to be oxidation abrasion from the observation of wear tracks. (Author)

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)

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

Science.gov (United States)

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

2015-01-01

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

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.

Floor tile glass-ceramic glaze for improvement of the resistance to surface abrasion

Science.gov (United States)

Gajek, M.; Lis, J.; Partyka, J.; Wójczyk, M.

2011-10-01

The results of research aimed at the study on frits and glass-ceramic glazes for floor tiles, based on compositions located in the primary field of cordierite crystallization within the system MgO-Al2O3-SiO2, have been presented. The results comprise investigations on the frits crystallization abilities, stability of the crystallizing phase under conditions of single-stage a fast firing cycle (time below 60 minutes) depending on their chemical composition and the influence of the nucleation agents. The influence of the nucleating agents namely TiO2, ZrO2, V2O5 on phase composition of obtained crystalline glazes, mechanical parameters and microstructure, has been examined. The strength tests proved increased mechanical resistance of crystalline glazes. Obtained glazes are characterized by high microhardness in range 6~8 GPa, as well as the increased wear resistance measured by the loss of weight below 100 mg / 55 cm2 (PN-EN ISO 10545-7). Significant increase of these parameters as compared with non-crystalline glazes, where micro-hardness values range between 5~6 GPa and the wear resistance values range from 120 to 200 mg, has been proved. Starting glasses (frits) and glazes of the ternary system MgO-SiO2-Al2O3, were examined with use of DTA, XRD and SEM methods.

Floor tile glass-ceramic glaze for improvement of the resistance to surface abrasion

International Nuclear Information System (INIS)

Gajek, M; Lis, J; Partyka, J; Wojczyk, M

2011-01-01

The results of research aimed at the study on frits and glass-ceramic glazes for floor tiles, based on compositions located in the primary field of cordierite crystallization within the system MgO-Al 2 O 3 -SiO 2 , have been presented. The results comprise investigations on the frits crystallization abilities, stability of the crystallizing phase under conditions of single-stage a fast firing cycle (time below 60 minutes) depending on their chemical composition and the influence of the nucleation agents. The influence of the nucleating agents namely TiO 2 , ZrO 2 , V 2 O 5 on phase composition of obtained crystalline glazes, mechanical parameters and microstructure, has been examined. The strength tests proved increased mechanical resistance of crystalline glazes. Obtained glazes are characterized by high microhardness in range 6∼8 GPa, as well as the increased wear resistance measured by the loss of weight below 100 mg / 55 cm 2 (PN-EN ISO 10545-7). Significant increase of these parameters as compared with non-crystalline glazes, where micro-hardness values range between 5∼6 GPa and the wear resistance values range from 120 to 200 mg, has been proved. Starting glasses (frits) and glazes of the ternary system MgO-SiO 2 -Al 2 O 3 , were examined with use of DTA, XRD and SEM methods.

Wear resistance and structural changes in nitrogen-containing high-chromium martensitic steels under conditions of abrasive wear and sliding friction

International Nuclear Information System (INIS)

Makarov, A.V.; Korshunov, L.G.; Schastlivtsev, V.M.; Chernenko, N.L.

1998-01-01

Martensitic nitrogen-containing steels Kh17N2A0.14, Kh13A0.14, Kh14G4A0.22 as well as steel 20Kh13 were studied for their wear resistance under conditions of friction and abrasion. Metallography, X ray diffraction analysis and electron microscopy were used to investigate the structural changes taking place in a thin surface layer on wearing. It is shown that an increase of nitrogen content of 0.14 to 0.22% promotes an enhancement of steel resistance to abrasive and adhesive wear, especially after tempering in the range of 500-550 deg C. Typically, the nitrogen-containing steels exhibit lower resistance to various types of wear in comparison with the steels with high-carbon martensite due to their lower deformability under conditions of friction loading

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

Directory of Open Access Journals (Sweden)

Daniel Petrosyan

2017-06-01

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

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

Coating of ceramic powders by chemical vapor deposition techniques (CVD)

International Nuclear Information System (INIS)

Haubner, R.; Lux, B.

1997-01-01

New ceramic materials with selected advanced properties can be designed by coating of ceramic powders prior to sintering. By variation of the core and coating material a large number of various powders and ceramic materials can be produced. Powders which react with the binder phase during sintering can be coated with stable materials. Thermal expansion of the ceramic materials can be adjusted by varying the coating thickness (ratio core/layer). Electrical and wear resistant properties can be optimized for electrical contacts. A fluidized bed reactor will be designed which allow the deposition of various coatings on ceramic powders. (author)

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

Directory of Open Access Journals (Sweden)

Moshkelgosha V

2016-06-01

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

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

Science.gov (United States)

V, Moshkelgosha; M, Shomali; M, Momeni

2016-06-01

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

Electrical resistivity measurements in superconducting ceramics

International Nuclear Information System (INIS)

Muccillo, R.; Bressiani, A.H.A.; Muccillo, E.N.S.; Bressiani, J.C.

1988-01-01

Electrical resistivity measurements have been done in (Y, Ba, Cu, O) - and (Y, A1, Ba, Cu, O) - based superconducting ceramics. The sintered specimens were prepared by applying gold electrodes and winding on the non-metalized part with a copper strip to be immersed in liquid nitrogen for cooling. The resistivity measurements have been done by the four-probe method. A copper-constantan or chromel-alumel thermocouple inserted between the specimen and the copper cold finger has been used for the determination of the critical temperature T c . Details of the experimental set-up and resistivity versus temperature plots in the LNT-RT range for the superconducting ceramics are the major contributions of this communication. (author) [pt

Electrical resistivity measurements in superconducting ceramics

International Nuclear Information System (INIS)

Muccillo, R.; Bressiani, A.H.A.; Muccillo, E.N.S.; Bressian, J.C.

1988-01-01

Electrical resistivity measurements have been done in (Y,Ba,Cu,O)- and (Y,Al,Ba,Cu,O)-based superconducting ceramics. The sintered specimens were prepared by applying gold electrodes and winding on the non-metalized part with a copper strip to be immersed in liquid nitrogen for cooling. The resistivity measurements have been done by the four-probe method. A copper constantan or chromel-alumel thermocouple inserted between the specimen and the copper cold finger has been used for the determination of the critical temperature T c . Details of the experimental set-up and resistivity versus temperature plots in the LNT-RT range for the superconducting ceramics are the major contributions of this communication. (author) [pt

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

Hemorrhagic iliopsoas bursitis complicating well-functioning ceramic-on-ceramic total hip arthroplasty.

Science.gov (United States)

Park, Kyung Soon; Diwanji, Sanket R; Kim, Hyung Keun; Song, Eun Kyoo; Yoon, Taek Rim

2009-08-01

Iliopsoas bursitis has been increasingly recognized as a complication of total hip arthroplasty and is usually associated with polyethylene wear. Here, the authors report a case of hemorrhagic iliopsoas bursitis complicating an otherwise well-functioning ceramic-on-ceramic arthroplasty performed by minimal invasive modified 2-incision technique. The bursitis in turn resulted in femoral nerve palsy and femoral vein compression. In this report, there was no evidence to support that the bursitis was due to an inflammatory response to ceramic wear particles or any other wear particles originating from the total hip arthroplasty.

Plasma transferred arc surface modification of atmospheric plasma sprayed ceramic coatings

Energy Technology Data Exchange (ETDEWEB)

Ulutan, Mustafa; Kilicay, Koray; Kaya, Esad; Bayar, Ismail [Dept. of Mechanical Engineering, Eskisehir Osmangazi University, Eskisehir (Turkmenistan)

2016-08-15

In this study, a 90MnCrV8 steel surface was coated with aluminum oxide and chromium oxide powders through the Atmospheric plasma spray (APS) and Plasma transferred arc (PTA) methods. The effects of PTA surface melting on the microstructure, hardness, and wear behavior were investigated. The microstructures of plasma-sprayed and modified layers were characterized by Optical microscopy (OM), Scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDS). The dry-sliding wear properties of the samples were determined through the ball-on-disk wear test method. Voids, cracks, and nonhomogeneous regions were observed in the microstructure of the APS ceramic-coated surface. These microstructure defects were eliminated by the PTA welding process. The microhardness of the samples was increased. Significant reductions in wear rate were observed after the PTA surface modification. The wear resistance of ceramic coatings increased 7 to 12 times compared to that of the substrate material.

The comparative studies of ADI versus Hadfield cast steel wear resistance

Directory of Open Access Journals (Sweden)

Mieczysław Kaczorowski

2011-04-01

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

Thermophysical properties of selected wear-resistant alloys

International Nuclear Information System (INIS)

Farwick, D.G.; Johnson, R.N.

1980-06-01

Thermophysical properties of 13 selected wear-resistant materials, including specific heat, thermal conductivity, thermal diffusivity, and thermal expansion (instantaneous, mean, and linear) are provided. The Center for Information and Numerical Data Analysis and Synthesis (CINDAS) at Purdue University supplied properties data

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.

Nitrogen implantation of type 303 stainless steel gears for improved wear and fatigue resistance

International Nuclear Information System (INIS)

Kustas, F.M.; Misra, M.S.; Tack, W.T.

1987-01-01

Fine-positioning mechanisms are responsible for accurate and reproducible control of aerospace system devices, i.e. filter grading wheels. Low wear and fatigue resistance of mechanism components, such as pinions and gears, can reduce system performance and reliability. Surface modification using ion implantation with nitrogen was used on type 303 stainless steel pinions and gears to increase tribological performance. Wear-life tests of untreated, nitrogen-implanted and nitrogen-implanted-and-annealed gears were performed in a fine-positioning mechanism under controlled environmental conditions. Wear and fatigue resistance were monitored at selected time intervals which were a percentage of the predicted failure life as determined by a numerical stress analysis. Surface analyses including scanning electron microscopy and Auger electron spectroscopy were performed to establish the wear and fatigue mechanisms and the nitrogen concentration-depth distributions respectively. Nitrogen implantation resulted in a significant improvement in both surface wear and fatigue spalling resistance over those of untreated gears. A 40% reduction in surface wear and a 44% reduction in dedendum spalling was observed. In contrast, the nitrogen-implanted-and-annealed gears showed a 46% increase in sliding wear area and an 11% increase in spall density compared with those of untreated gears, indicating that the post-implantation anneal was detrimental to wear and fatigue resistance. (orig.)

Microstructure and wear characterization of self-lubricating Al2O3 - MoS2 composite ceramic coatings

International Nuclear Information System (INIS)

Koshkarian, K.A.; Kriven, W.M.

1989-01-01

The authors report the results of composite ceramic coatings of alumina Al 2 O 3 containing some molybdenum disulfide MoS 2 electro-codeposited on to Al metal substrates by a combination of anodic sparks deposition of Al 2 O 3 and electrophoresis of MoS 2 . The microstructures were characterized by XRD, XPS, SEM, EDS, SNMS, TEM, SAD and relative wear resistance measurements. The coatings consisted mostly of Al 2 O 3 with some and present as well. The coatings were porous and microcracked. SEM showed them to consist of circular splats which had rapidly crystallized from the molten state in areas of dielectric breakdown in the coating. In the TEM the microstructure was seen to contain sets of parallel, elongated grains having a single crystallographic orientation. The grains were separated by dislocated, low angle grain boundaries or microcracks. The sets intersected at irregularly curved interfaces and were mechanically interlocked. Quantitative SNMS indicated that up to 26 wt% MoS 2 was incorporated in coatings fabricated from 5g/1 solutions. SEM/EDS as well as TEM/SAD/EDS identified 1-3 μ particles of MoS 2 incorporated into the 5g/1 solution derived coatings. These coatings exhibited 50% lower wear rate than pure alumina coatings deposited under the same condition

Floor tile glass-ceramic glaze for improvement of the resistance to surface abrasion

Energy Technology Data Exchange (ETDEWEB)

Gajek, M; Lis, J; Partyka, J; Wojczyk, M, E-mail: mgajek@agh.edu.pl [AGH University of Science and Technology, Faculty of Materials Science and Ceramic, al. Mickiewicza 30, 30-059 Cracow (Poland)

2011-10-29

The results of research aimed at the study on frits and glass-ceramic glazes for floor tiles, based on compositions located in the primary field of cordierite crystallization within the system MgO-Al{sub 2}O{sub 3}-SiO{sub 2}, have been presented. The results comprise investigations on the frits crystallization abilities, stability of the crystallizing phase under conditions of single-stage a fast firing cycle (time below 60 minutes) depending on their chemical composition and the influence of the nucleation agents. The influence of the nucleating agents namely TiO{sub 2}, ZrO{sub 2}, V{sub 2}O{sub 5} on phase composition of obtained crystalline glazes, mechanical parameters and microstructure, has been examined. The strength tests proved increased mechanical resistance of crystalline glazes. Obtained glazes are characterized by high microhardness in range 6{approx}8 GPa, as well as the increased wear resistance measured by the loss of weight below 100 mg / 55 cm{sup 2} (PN-EN ISO 10545-7). Significant increase of these parameters as compared with non-crystalline glazes, where micro-hardness values range between 5{approx}6 GPa and the wear resistance values range from 120 to 200 mg, has been proved. Starting glasses (frits) and glazes of the ternary system MgO-SiO{sub 2}-Al{sub 2}O{sub 3}, were examined with use of DTA, XRD and SEM methods.

Metal-ceramic composite coatings obtained by new thermal spray technologies: Cold Gas Spray (CGS) and its wear resistance; Recubrimientos de materiales compuestos metal-ceramico obtenidos por nuevas tecnologias de proyeccion termica: Proyeccion fria (CGS) y su resistencia al desgaste

Energy Technology Data Exchange (ETDEWEB)

Miguel, J. M.; Vizcaino, S.; Dosta, S.; Cinca, N.; Lorenzana, C.; Guilemany, J. M.

2011-07-01

In this paper, composite coatings composed by an aluminum bronze metal matrix and a hard ceramic alumina phase obtained by cold spray technique were obtained in order to increase the tribological properties of the pure bronze coatings. The different processes that occur during the coating formation (hardening of the metal particles, fragmentation of the ceramic particles, shot peening on the metal substrate, etc) are described and their effects on the coating properties are studied. Wear tests consisting on Ball-on-Disk tests, abrasion Rubber Wheel tests and erosion tests as well as microhardness and adhesion tests are carried out and the results are correlated with the ceramic phase content of the coatings. It can be concluded that the hard ceramic phase increases the tribological properties with relation of the initial bronze coating. Finally, main wear mechanisms during the tribological tests are described. (Author) 21 refs.

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

Directory of Open Access Journals (Sweden)

WANG Huai-yuan

2017-01-01

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

Predictive Surface Roughness Model for End Milling of Machinable Glass Ceramic

Energy Technology Data Exchange (ETDEWEB)

Reddy, M Mohan; Gorin, Alexander [School of Engineering and Science, Curtin University of Technology, Sarawak (Malaysia); Abou-El-Hossein, K A, E-mail: mohan.m@curtin.edu.my [Mechanical and Aeronautical Department, Nelson Mandela Metropolitan University, Port Elegebeth, 6031 (South Africa)

2011-02-15

Advanced ceramics of Machinable glass ceramic is attractive material to produce high accuracy miniaturized components for many applications in various industries such as aerospace, electronics, biomedical, automotive and environmental communications due to their wear resistance, high hardness, high compressive strength, good corrosion resistance and excellent high temperature properties. Many research works have been conducted in the last few years to investigate the performance of different machining operations when processing various advanced ceramics. Micro end-milling is one of the machining methods to meet the demand of micro parts. Selecting proper machining parameters are important to obtain good surface finish during machining of Machinable glass ceramic. Therefore, this paper describes the development of predictive model for the surface roughness of Machinable glass ceramic in terms of speed, feed rate by using micro end-milling operation.

Predictive Surface Roughness Model for End Milling of Machinable Glass Ceramic

International Nuclear Information System (INIS)

Reddy, M Mohan; Gorin, Alexander; Abou-El-Hossein, K A

2011-01-01

Advanced ceramics of Machinable glass ceramic is attractive material to produce high accuracy miniaturized components for many applications in various industries such as aerospace, electronics, biomedical, automotive and environmental communications due to their wear resistance, high hardness, high compressive strength, good corrosion resistance and excellent high temperature properties. Many research works have been conducted in the last few years to investigate the performance of different machining operations when processing various advanced ceramics. Micro end-milling is one of the machining methods to meet the demand of micro parts. Selecting proper machining parameters are important to obtain good surface finish during machining of Machinable glass ceramic. Therefore, this paper describes the development of predictive model for the surface roughness of Machinable glass ceramic in terms of speed, feed rate by using micro end-milling operation.

Dry sliding wear behavior of heat treated hybrid metal matrix composite using Taguchi techniques

International Nuclear Information System (INIS)

Kiran, T.S.; Prasanna Kumar, M.; Basavarajappa, S.; Viswanatha, B.M.

2014-01-01

Highlights: • ZA-27 alloy is used as matrix material and reinforced with SiC and Gr particles. • Heat treatment was carried out for all specimen. • Dry sliding wear test was done on pin-on-disc apparatus by Taguchi technique. • ZA-27/9SiC–3Gr showed superior wear resistance over the base alloy. • Ceramic mixed mechanical layer on contact surface of composite was formed. - Abstract: Dry sliding wear behavior of zinc based alloy and composite reinforced with SiCp (9 wt%) and Gr (3 wt%) fabricated by stir casting method was investigated. Heat treatment (HT) and aging of the specimen were carried out, followed by water quenching. Wear behavior was evaluated using pin on disc apparatus. Taguchi technique was used to estimate the parameters affecting the wear significantly. The effect of HT was that it reduced the microcracks, residual stresses and improved the distribution of microconstituents. The influence of various parameters like applied load, sliding speed and sliding distance on wear behavior was investigated by means and analysis of variance (ANOVA). Further, correlation between the parameters was determined by multiple linear regression equation for each response. It was observed that the applied load significantly influenced the wear volume loss (WVL), followed by sliding speed implying that increase in either applied load or sliding speed increases the WVL. Whereas for composites, sliding distance showed a negative influence on wear indicating that increase in sliding distance reduces WVL due to the presence of reinforcements. The wear mechanism of the worn out specimen was analyzed using scanning electron microscopy. The analysis shows that the formation and retention of ceramic mixed mechanical layer (CMML) plays a major role in the dry sliding wear resistance

Fabrication and characterization of glass–ceramics materials developed from steel slag waste

International Nuclear Information System (INIS)

He, Feng; Fang, Yu; Xie, Junlin; Xie, Jun

2012-01-01

Highlights: ► Steelmaking slag (SS) is one of the most common industrial wastes. ► Glass–ceramics produced from SS is observed to have good properties. ► A large volume of raw SS can be recycled. ► The utilization of SS could reduce solid waste pollution. -- Abstract: In this study, glass–ceramic materials were produced from SS (steel slag) obtained from Wuhan Iron and Steel Corporation in China. The amount of SS used in glass batch was about 31–41 wt.% of the total batch mixture. On basis of differential thermal analysis (DTA) results, the nucleation and crystallization temperature of the parent glass samples were identified, respectively. X-ray diffraction (XRD) revealed that multiple crystalline phases coexisted in the glass–ceramics, and the main crystalline phase was wollastonite (CaSiO 3 ). SEM observation indicated that there was an increase in the amount of crystalline phase in the glass–ceramics when the CaO content and crystallization time increased. It was also found that the glass–ceramics with fine microstructure enhance mechanical properties and erosion wear resistance. The obtained glass–ceramics showed a maximum bending strength of 145.6 MPa and very nice wear resistance. Therefore, it is feasible to produce nucleated glass–ceramics materials for building and decorative materials from SS.

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 resistance of AISI 304 stainless steel submitted to low temperature plasma carburizing

Directory of Open Access Journals (Sweden)

Marcos Antônio Barcelos

Full Text Available Abstract Despite the AISI 304 stainless steel has high corrosion/oxidation resistance, its tribological properties are poor, being one of the barriers for use in severe wear applications. Thus, there is a wide field for studying technologies that aim to increase the surface hardness and wear resistance of this material. In this work, hardness and wear resistance for AISI 304 stainless steel submitted to the thermochemical treatment by low temperature plasma carburizing (LTPC in a fixed gas mixture composition of 93% H2 and 7% CH4 are presented. Through the evaluation of the carburizing layers, it was possible to observe a substantial improvement in tribological properties after all temperature and time of treatment. This improvement is directly related to the increase of the process variables; among them temperature has a stronger influence on the wear resistance obtained using LTPC process.

Wear Resistance of TiC Reinforced Cast Steel Matrix Composite

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Sobula S.

2017-03-01

Full Text Available Wear resistance of TiC-cast steel metal matrix composite has been investigated. Composites were obtained with SHSB method known as SHS synthesis during casting. It has been shown the differences in wear between composite and base cast steel. The Miller slurry machine test were used to determine wear loss of the specimens. The slurry was composed of SiC and water. The worn surface of specimens after test, were studied by SEM. Experimental observation has shown that surface of composite zone is not homogenous and consist the matrix lakes. Microscopic observations revealed the long grooves with SiC particles indented in the base alloy area, and spalling pits in the composite area. Due to the presence of TiC carbides on composite layer, specimens with TiC reinforced cast steel exhibited higher abrasion resistance. The wear of TiC reinforced cast steel mechanism was initially by wearing of soft matrix and in second stage by polishing and spalling of TiC. Summary weight loss after 16hr test was 0,14÷0,23 g for composite specimens and 0,90 g for base steel.

Mechanical properties of ceramics

CERN Document Server

Pelleg, Joshua

2014-01-01

This book discusses the mechanical properties of ceramics and aims to provide both a solid background for undergraduate students, as well as serving as a text to bring practicing engineers up to date with the latest developments in this topic so they can use and apply these to their actual engineering work.  Generally, ceramics are made by moistening a mixture of clays, casting it into desired shapes and then firing it to a high temperature, a process known as 'vitrification'. The relatively late development of metallurgy was contingent on the availability of ceramics and the know-how to mold them into the appropriate forms. Because of the characteristics of ceramics, they offer great advantages over metals in specific applications in which hardness, wear resistance and chemical stability at high temperatures are essential. Clearly, modern ceramics manufacturing has come a long way from the early clay-processing fabrication method, and the last two decades have seen the development of sophisticated technique...

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

Resistance to abrasion of extrinsic porcelain esthetic characterization techniques.

Science.gov (United States)

Chi, Woo J; Browning, William; Looney, Stephen; Mackert, J Rodway; Windhorn, Richard J; Rueggeberg, Frederick

2017-01-01

A novel esthetic porcelain characterization technique involves mixing an appropriate amount of ceramic colorants with clear, low-fusing porcelain (LFP), applying the mixture on the external surfaces, and firing the combined components onto the surface of restorations in a porcelain oven. This method may provide better esthetic qualities and toothbrush abrasion resistance compared to the conventional techniques of applying color-corrective porcelain colorants alone, or applying a clear glaze layer over the colorants. However, there is no scientific literature to support this claim. This research evaluated toothbrush abrasion resistance of a novel porcelain esthetic characterization technique by subjecting specimens to various durations of simulated toothbrush abrasion. The results were compared to those obtained using the conventional characterization techniques of colorant application only or colorant followed by placement of a clear over-glaze. Four experimental groups, all of which were a leucite reinforced ceramic of E TC1 (Vita A1) shade, were prepared and fired in a porcelain oven according to the manufacturer's instructions. Group S (stain only) was characterized by application of surface colorants to provide a definitive shade of Vita A3.5. Group GS (glaze over stain) was characterized by application of a layer of glaze over the existing colorant layer as used for Group S. Group SL (stain+LFP) was characterized by application of a mixture of colorants and clear low-fusing add-on porcelain to provide a definitive shade of Vita A3.5. Group C (Control) was used as a control without any surface characterization. The 4 groups were subjected to mechanical toothbrushing using a 1:1 water-to-toothpaste solution for a simulated duration of 32 years of clinical use. The amount of wear was measured at time intervals simulating every 4 years of toothbrushing. These parameters were evaluated longitudinally for all groups as well as compared at similar time points among

Friction and wear behaviour of ion beam modified ceramics

International Nuclear Information System (INIS)

Lankford, J.; Wei, W.; Kossowsky, R.

1987-01-01

In the present study, the sliding friction coefficients and wear rates of carbide, oxide, and nitride materials for potential use as sliding seals (ring/liner) were measured under temparature, environmental, velocity, and loading conditions representative of a diesel engine. In addition, silicon nitride and partially stabilized zirconia discs were modified by ion mixing with TiNi, nickel, cobalt and chromium, and subsequently run against carbide pins, with the objective of producing reduced friction via solid lubrication at elevated temperature. Unmodified ceramic sliding couples were characterized at all temperatures by friction coefficients of 0.24 and above. However, the coefficient at 800 0 C in an oxidizing environment was reduced to below 0.1, for certain material combinations, by the ion implantation of TiNi or cobalt. This beneficial effect was found to derive from lubricious titanium, nickel, and cobalt oxides. (author)

Friction and wear behaviour of ion beam modified ceramics

Science.gov (United States)

Lankford, J.; Wei, W.; Kossowsky, R.

1987-01-01

In the present study, the sliding friction coefficients and wear rates of carbide, oxide, and nitride materials for potential use as sliding seals (ring/liner) were measured under temperature, environmental, velocity, and loading conditions representative of a diesel engine. In addition, silicon nitride and partially stabilized zirconia discs were modified by ion mixing with TiNi, nickel, cobalt and chromium, and subsequently run against carbide pins, with the objective of producing reduced friction via solid lubrication at elevated temperature. Unmodified ceramic sliding couples were characterized at all temperatures by friction coefficients of 0.24 and above. However, the coefficient at 800 C in an oxidizing environment was reduced to below 0.1, for certain material combinations, by the ion implantation of TiNi or cobalt. This beneficial effect was found to derive from lubricious titanium, nickel, and cobalt oxides.

Abrasive Wear of AlSi12-Al2O3 Composite Materials Manufactured by Pressure Infiltration

Directory of Open Access Journals (Sweden)

Kremzer M.

2016-09-01

Full Text Available The aim of this study is to investigate tribological properties of EN AC-AlSi12 alloy composite materials matrix manufactured by pressure infiltration of Al2O3 porous preforms. In the paper, a technique of manufacturing composite materials was described in detail as well as wear resistance made on pin on disc was tested. Metallographic observations of wear traces of tested materials using stereoscopic and confocal microscopy were made. Studies allow concluding that obtained composite materials have much better wear resistance than the matrix alloy AlSi12. It was further proved that the developed technology of their preparation consisting of pressure infiltration of porous ceramic preforms can find a practical application.

Friction and wear properties of novel HDPE--HAp--Al2O3 biocomposites against alumina counterface.

Science.gov (United States)

Bodhak, Subhadip; Nath, Shekhar; Basu, Bikramjit

2009-03-01

In an effort to enhance physical properties of biopolymers (high-density polyethylene, HDPE) in terms of elastic modulus and hardness, various ceramic fillers, like alumina (Al2O3) and hydroxyapatite (HAp) are added, and therefore it is essential to assess the friction and wear resistance properties of HDPE biocomposites. In this perspective, HDPE composites with varying ceramic filler content (upto 40 vol%) were fabricated under the optimal compression molding conditions and their friction and wear properties were evaluated against Al2O3 at fretting contacts. All the experiments were conducted at a load of 10 N for duration of 100,000 cycles in both dry as well as simulated body fluid (SBF). Such planned set of experiments has been designed to address three important issues: (a) whether the improvement in physical properties (hardness, E-modulus) will lead to corresponding improvement in friction and wear properties; (b) whether the fretting in SBF will provide sufficient lubrication in order to considerably enhance the tribological properties, as compared to that in ambient conditions; and (c) whether the generation of wear debris particles be reduced for various compositionally modified polymer composites, in comparison to unreinforced HDPE. The experimental results indicate the possibility of achieving extremely low coefficient of friction (COF approximately 0.047) as well as higher wear resistance (wear rate in the order of approximately 10(-7) mm3 N(-1) m(-1)) with the newly developed composites in SBF. A low wear depth of 3.5-4 microm is recorded, irrespective of fretting environment. Much effort has been put forward to correlate the friction and wear mechanisms with abrasion, adhesion, and wear debris formation.

Proceedings of the national symposium on materials and processing: functional glass/glass-ceramics, advanced ceramics and high temperature materials

International Nuclear Information System (INIS)

Ghosh, A.; Sahu, A.K.; Viswanadham, C.S.; Ramanathan, S.; Hubli, R.C.; Kothiyal, G.P.

2012-10-01

With the development of materials science it is becoming increasingly important to process some novel materials in the area of glass, advanced ceramics and high temperature metals/alloys, which play an important role in the realization of many new technologies. Such applications demand materials with tailored specifications. Glasses and glass-ceramics find exotic applications in areas like radioactive waste storage, optical communication, zero thermal expansion coefficient telescopic mirrors, human safety gadgets (radiation resistance windows, bullet proof apparels, heat resistance components etc), biomedical (implants, hyperthermia treatment, bone cement, bone grafting etc). Advanced ceramic materials have been beneficial in biomedical applications due to their strength, biocompatibility and wear resistance. Non-oxide ceramics such as carbides, borides, silicides, their composites, refractory metals and alloys are useful as structural and control rod components in high temperature fission/ fusion reactors. Over the years a number of novel processing techniques like selective laser melting, microwave heating, nano-ceramic processing etc have emerged. A detailed understanding of the various aspects of synthesis, processing and characterization of these materials provides the base for development of novel technologies for different applications. Keeping this in mind and realizing the need for taking stock of such developments a National Symposium on Materials and Processing -2012 (MAP-2012) was planned. The topics covered in the symposium are ceramics, glass/glass-ceramics and metals and materials. Papers relevant to INIS are indexed separately

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

International Nuclear Information System (INIS)

Zhang, Yanning; Sahasrabudhe, Himanshu; Bandyopadhyay, Amit

2015-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-08-15

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

Thermally-treated Pt-coated silicon AFM tips for wear resistance in ferroelectric data storage

International Nuclear Information System (INIS)

Bhushan, Bharat; Palacio, Manuel; Kwak, Kwang Joo

2008-01-01

In ferroelectric data storage, a conductive atomic force microscopy (AFM) probe with a noble metal coating is placed in contact with a lead zirconate titanate (PZT) film. The understanding and improvement of probe tip wear, particularly at high velocities, is needed for high data rate recording. A commercial Pt-coated silicon AFM probe was thermally treated in order to form platinum silicide at the near-surface. Nanoindentation, nanoscratch and wear experiments were performed to evaluate the mechanical properties and wear performance at high velocities. The thermally treated tip exhibited lower wear than the untreated tip. The tip wear mechanism is adhesive and abrasive wear with some evidence of impact wear. The enhancement in mechanical properties and wear resistance in the thermally treated film is attributed to silicide formation in the near-surface. Auger electron spectroscopy and electrical resistivity measurements confirm the formation of platinum silicide. This study advances the understanding of thin film nanoscale surface interactions

Microstructure and wear resistance of high chromium cast iron containing niobium

Directory of Open Access Journals (Sweden)

Zhang Zhiguo

2014-05-01

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

Single layer and multilayer wear resistant coatings of (Ti,Al)N: a review

International Nuclear Information System (INIS)

PalDey, S.; Deevi, S.C.

2003-01-01

We review the status of (Ti,Al)N based coatings obtained by various physical vapor deposition (PVD) techniques and compare their properties. PVD techniques based on sputtering and cathodic arc methods are widely used to deposit wear resistant (Ti,Al)N coatings. These techniques were further modified to improve the metal ionization rate and to eliminate macrodroplets from plasma streams. We summarize manufacture of target/cathode, substrate materials for deposition of coatings, deposition parameters, and the effect of deposition parameters on the physical and mechanical properties of (Ti,Al)N coatings. It is shown that (Ti,Al)N coatings by PVD enhance the wear, thermal, and oxidation resistance of a wide variety of tool materials. We discuss the wear resistant properties of (Ti,Al)N for various machining applications as compared with coatings such as TiN, Ti(C,N) and (Ti,Zr)N. High hardness (∼28-32 GPa), relatively low residual stress (∼5 GPa), superior oxidation resistance, high hot hardness, and low thermal conductivity make (Ti,Al)N coatings most desirable in dry machining and machining of abrasive alloys at high speeds. Multicomponent coatings based on different metallic and nonmetallic elements combine the benefit of individual components leading to a further refinement of coating properties. Alloying additions such as Cr and Y drastically improve the oxidation resistance, Zr and V improve the wear resistance, whereas, Si increases the hardness and resistance to chemical reactivity of the film. Addition of boron improves the abrasive wear behavior of Ti-Al based coatings due to the formation of TiB 2 and BN phases depending on the deposition conditions. Hafnium based nitrides and carbides have potential for resistance to flank and crater wear. The presence of a large number of interfaces between individual layers of a multilayered structure results in a drastic increase in hardness and strength. (Ti,Al)N multilayer super lattice coatings with lattice

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.

Microtensile Bond Strength of New Ceramic/Polymer Materials Repaired with Composite Resin

Science.gov (United States)

2015-06-30

also have been shown to have higher enamel wear rates than composite-resin CAD/CAM restorations (Mӧrmann et al, 2013). As material choices, cost, and...although the longevity of these repairs has not been validated by clinical studies. Paradigm MZ100 showed the least amount of opposing enamel wear...ability to absorb shock, resist staining and stop crack propagation. Further manufacturer claims are that ceramic/polymer materials are easily

[Comparison of in vivo characteristics of polyethylene wear particles produced by a metal and a ceramic femoral component in total knee replacement].

Science.gov (United States)

Veigl, D; Vavřík, P; Pokorný, D; Slouf, M; Pavlova, E; Landor, I

2011-01-01

The aim of the study was to evaluate in vivo and compare, in terms of the quality and number of ultra high-molecular polyethylene (UHMWPE) wear particles, total knee replacements of identical construction differing only in the material used for femoral component production, i.e., CoCrMo alloy or ZrO2 ceramics. Samples of peri-prosthetic granuloma tissue were collected in two patients with total knee replacement suffering from implant migration, who were matched in relevant characteristics. The primary knee replacement in Patient 1 with a CoCrMo femoral component was done 7.2 years and in Patient 2 with a ZrO2 implant 6.8 years before this assessment. The polyethylene wear-induced granuloma was analysed by the MORF method enabling us to assess the shape and size of wear debris and the IRc method for assessment of particle concentration. In the granuloma tissue samples of Patient 1, on the average, particles were 0.30 mm in size and their relative volume was 0.19. In the Patient 2 tissue samples, the average size of particles was 0.33 mm and their relative volume was 0.26. There was no significant difference in either particle morphology or their concentration in the granuloma tissue between the two patients. One of the options of how to reduce the production of polyethylene wear particles is to improve the tribological properties of contacting surfaces in total knee replacement by substituting a cobalt-chrome femoral component with a zirconia ceramic femoral component. The previous in vitro testing carried out with a mechanical simulator under conditions approaching real weight-bearing in the human body did show a nearly three-fold decrease in the number of UHMWPE wear particles in zirconia components. The evaluation of granuloma tissue induced by the activity of a real prosthetic joint for nearly seven years, however, did not reveal any great difference in either quality or quantity of polyethylene debris between the two replacements. The difference of surface

The wear and corrosion resistance of shot peened-nitrided 316L austenitic stainless steel

International Nuclear Information System (INIS)

Hashemi, B.; Rezaee Yazdi, M.; Azar, V.

2011-01-01

Research highlights: → Shot peening-nitriding increased the wear resistance and surface hardness of samples. → This treatment improved the surface mechanical properties. → Shot peening alleviates the adverse effects of nitriding on the corrosion behavior. -- Abstract: 316L austenitic stainless steel was gas nitrided at 570 o C with pre-shot peening. Shot peening and nitriding are surface treatments that enhance the mechanical properties of surface layers by inducing compressive residual stresses and formation of hard phases, respectively. The structural phases, micro-hardness, wear behavior and corrosion resistance of specimens were investigated by X-ray diffraction, Vickers micro-hardness, wear testing, scanning electron microscopy and cyclic polarization tests. The effects of shot peening on the nitride layer formation and corrosion resistance of specimens were studied. The results showed that shot peening enhanced the nitride layer formation. The shot peened-nitrided specimens had higher wear resistance and hardness than other specimens. On the other hand, although nitriding deteriorated the corrosion resistance of the specimens, cyclic polarization tests showed that shot peening before the nitriding treatment could alleviate this adverse effect.

Supersonic laser spray of aluminium alloy on a ceramic substrate

International Nuclear Information System (INIS)

Riveiro, A.; Lusquinos, F.; Comesana, R.; Quintero, F.; Pou, J.

2007-01-01

Applying a ceramic coating onto a metallic substrate to improve its wear resistance or corrosion resistance has attracted the interest of many researchers during decades. However, only few works explore the possibility to apply a metallic layer onto a ceramic material. This work presents a novel technique to coat ceramic materials with metals: the supersonic laser spraying. In this technique a laser beam is focused on the surface of the precursor metal in such a way that the metal is transformed to the liquid state in the beam-metal interaction zone. A supersonic jet expels the molten material and propels it to the surface of the ceramic substrate. In this study, we present the preliminary results obtained using the supersonic laser spray to coat a commercial cordierite ceramic plate with an Al-Cu alloy using a 3.5 kW CO 2 laser and a supersonic jet of Argon. Coatings were characterized by scanning electron microscopy (SEM) and interferometric profilometry

Wear resistance of layers hard faced by the high-alloyed filler metal

Directory of Open Access Journals (Sweden)

Dušan Arsić

2016-10-01

Full Text Available The objective of this work was to determine the wear resistance of layers hard faced by the high-alloyed filler metal, with or without the austenite inter-layer, on parts that operate at different sliding speeds in conditions without lubrication. The samples were hard faced with the filler metal E 10-UM-60-C with high content of C, Cr and W. Used filler metal belongs into group of alloys aimed for reparatory hard facing of parts damaged by abrasive and erosive wear and it is characterized by high hardness and wear resistance. In experiments, the sliding speed and the normal loading were varied and the wear scar was monitored, based on which the volume of the worn material was calculated analytically. The contact duration time was monitored over the sliding path of 300 mm. The most intensive wear was established for the loading force of 100 N and the sliding speed of 1 m.s-1, though the significant wear was also noticed in conditions of the small loading and speed of 0.25 m.s-1, which was even greater that at larger speeds.

Aligned composite structures for mitigation of impact damage and resistance to wear in dynamic environments

Science.gov (United States)

Mulligan, Anthony C.; Rigali, Mark J.; Sutaria, Manish P.; Popovich, Dragan; Halloran, Joseph P.; Fulcher, Michael L.; Cook, Randy C.

2009-04-14

Fibrous monolith composites having architectures that provide increased flaw insensitivity, improved hardness, wear resistance and damage tolerance and methods of manufacture thereof are provided for use in dynamic environments to mitigate impact damage and increase wear resistance.

Corrosion and wear resistant metallic layers produced by electrochemical methods

DEFF Research Database (Denmark)

Christoffersen, Lasse; Maahn, Ernst Emanuel

1999-01-01

Corrosion and wear-corrosion properties of novel nickel alloy coatings with promising production characteristics have been compared with conventional bulk materials and hard platings. Corrosion properties in neutral and acidic environments have been investigated with electrochemical methods....... Determination of polarisation resistance during 100 hours followed by stepwise anodic polarisation seems to be a promising technique to obtain steady state data on slowly corroding coatings with transient kinetics. A slurry test enables determination of simultaneous corrosion and abrasive wear. Comparison...... of AISI 316, hard chromium and hardened Ni-P shows that there is no universal correlation between surface hardness and wear-corrosion loss. The possible relation between questionable passivity of Ni-P coatings and their high wear-corrosion loss rate compared to hard chromium is discussed....

A new approach for assessing the wear resistance of soft ductile materials

International Nuclear Information System (INIS)

Zaid, A.I.O.; Banna, M.A.E.

2007-01-01

Aluminum and its alloys are the most versatile and attractive metallic materials which have been used for many decades in many engineering applications specially in the automobile and airspace industries due to their high strength-to- weight ratio, thermal conductivity, electrical conductivity, corrosion and wear resistances. Wear is the loss of material from a surface caused by interaction with another material. The main mechanisms of interaction are applied loads and relative motion, which can cause adhesion or/and abrasion, all of which leads to material loss. Therefore, most of the suggested methods, theoretical and empirical, for estimating the wear resistance of material is based on the mass loss, irrespective of the material or type of existing wear. Experimental observations reveal that in some situations, especially for soft and ductile materials, the tested specimen showed little or no mass loss while its dimensions and shape have suffered from plastic deformation which causes more damage than mass loss. Similar phenomenon was observed during electric spot welding of aluminum and zinc coated steels at the area beneath the electrode where plastic deformation takes place, causing increase in area which reduces the current density, will be also discussed in the paper. The amount of the plastic deformation, even when mentioned in some publications, was neglected in assessing wear resistance. In this paper, a model based on the plastic deformation at the worn end together with the mass loss is forwarded and discussed. The model was tested qualitatively using commercially pure aluminum of 99.97% purity in the as supplied condition and in grain refined conditions by some rare earth materials e.g. titanium and titanium plus boron, which are normally used in industry for improving its hardness and mechanical behavior. The wear tests were carried out under different loads and speeds (the main parameters in assessing wear resistance) and the data was used for

X-ray residual stress measurement and its variation during plane bending fatigue and sliding wear processes in TiC, TiN, TiB2 and Al2O3 coated carbon steels

International Nuclear Information System (INIS)

Endoh, Takashi; Idemitsu, Kohji; Kawakami, Mamoru

1993-01-01

The development of ceramic coating to metals was stimulated by the need for high temperature, wear and corrosion resistant materials. Recently TiC, TiN, TiB 2 and Al 2 O 3 are used as ceramic coating materials. In the present study, the X-ray method was successfully applied to measure the residual stress distribution in their ceramics coated steels. The X-ray elastic constants were determined and compared with the mechanically measured values. And plane bending and sliding wear tests were carried out. The X-ray method was successfully applied to measure the residual stress changes during fatigue and wear processes. The relationship between the change of residual stress and damage accumulation was investigated. (author)

Wear-resistant powder materials with intermetallic hardening. I. Nonporous materials for antifriction purposes

Energy Technology Data Exchange (ETDEWEB)

Karapetyan, G.K.; Akopov, N.L.; Karapetyan, F.K.; Manukyan, N.N.

1987-09-01

This article investigates the wear resistance, microhardness, microstructure, and crystal-phase behavior of a molybdenum alloy solid lubricant under cyclic wear and sliding friction tests against steel 45. Calculated and experimental results are given.

Edge loading has a paradoxical effect on wear in metal-on-polyethylene total hip arthroplasties.

Science.gov (United States)

Harris, William H

2012-11-01

Edge wear is an adverse factor that can negatively impact certain THAs. In some metal-on-metal THAs, it can lead to adverse tissue reactions including aseptic lymphocytic vasculitis-associated lesions and even to pseudotumor formation. In some ceramic-on-ceramic THAs, it can lead to squeaking and/or stripe wear. Edge wear in metal-on-metal and ceramic-on-ceramic THAs can also be associated with accelerated wear across the articulation of these joints. I asked: Does edge wear occur in metal-on-polyethylene (MOP) articulations? And if so, does it increase joint wear? I examined the evidence in the literature for edge wear occurring in MOP THA and then assessed the evidence in the literature for data supporting the concept that edge wear in MOP hips could accelerate wear across the articulation over time. Extensive data in the literature confirm edge wear is common in MOP THA. Surprisingly, the evidence does not support that it accelerates wear across the articulation. In fact, substantial data support the concept that it does not. These observations suggest, in terms of edge wear accelerating overall wear, MOP articulation may have a privileged position compared to hard-on-hard THA articulations.

Development of abrasion resistant glass-ceramics from industrial waste products. Final report

Energy Technology Data Exchange (ETDEWEB)

von Roode, M.

1983-05-26

Slag-ceramics were produced from glass compositions using pelletized slag as the major ingredient. The abrasion resistance, fracture toughness and microstructure of the prepared glass and glass-ceramics were evaluated. Glas-ceramics with good abrasion resistance were obtained when iron oxide in conjunction with carbon was used as a nucleating agent. 5 figs., 11 tabs.

Randomized, Controlled Clinical Trial of Bilayer Ceramic and Metal-Ceramic Crown Performance

Science.gov (United States)

Esquivel-Upshaw, Josephine; Rose, William; Oliveira, Erica; Yang, Mark; Clark, Arthur E.; Anusavice, Kenneth

2013-01-01

Purpose Analyzing the clinical performance of restorative materials is important, as there is an expectation that these materials and procedures will restore teeth and do no harm. The objective of this research study was to characterize the clinical performance of metal-ceramic crowns, core ceramic crowns, and core ceramic/veneer ceramic crowns based on 11 clinical criteria. Materials and Methods An IRB-approved, randomized, controlled clinical trial was conducted as a single-blind pilot study. The following three types of full crowns were fabricated: (1) metal-ceramic crown (MC) made from a Pd-Au-Ag-Sn-In alloy (Argedent 62) and a glass-ceramic veneer (IPS d.SIGN veneer); (2) non-veneered (glazed) lithium disilicate glass-ceramic crown (LDC) (IPS e.max Press core and e.max Ceram Glaze); and (3) veneered lithia disilicate glass-ceramic crown (LDC/V) with glass-ceramic veneer (IPS Empress 2 core and IPS Eris). Single-unit crowns were randomly assigned. Patients were recalled for each of 3 years and were evaluated by two calibrated clinicians. Thirty-six crowns were placed in 31 patients. A total of 12 crowns of each of the three crown types were studied. Eleven criteria were evaluated: tissue health, marginal integrity, secondary caries, proximal contact, anatomic contour, occlusion, surface texture, cracks/chips (fractures), color match, tooth sensitivity, and wear (of crowns and opposing enamel). Numerical rankings ranged from 1 to 4, with 4 being excellent, and 1 indicating a need for immediate replacement. Statistical analysis of the numerical rankings was performed using a Fisher’s exact test. Results There was no statistically significant difference between performance of the core ceramic crowns and the two veneered crowns at year 1 and year 2 (p > 0.05). All crowns were rated either as excellent or good for each of the clinical criteria; however, between years 2 and 3, gradual roughening of the occlusal surface occurred in some of the ceramic-ceramic crowns

Corrosion Behavior of Titanium Based Ceramic Coatings Deposited on Steels

OpenAIRE

Ali, Rania

2016-01-01

Titanium based ceramic films are increasingly used as coating materials because of their high hardness, excellent wear resistance and superior corrosion resistance. Using electrochemical and spectroscopic techniques, the electrochemical properties of different coatings deposited on different steels under different conditions were examined in this study. Thin films of titanium nitride (TiN), titanium diboride (TiB2), and titanium boronitride with different boron concentrations (TiBN-1&2) w...

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

Wear resistance of poly(2-methacryloyloxyethyl phosphorylcholine)-grafted carbon fiber reinforced poly(ether ether ketone) liners against metal and ceramic femoral heads.

Science.gov (United States)

Yamane, Shihori; Kyomoto, Masayuki; Moro, Toru; Hashimoto, Masami; Takatori, Yoshio; Tanaka, Sakae; Ishihara, Kazuhiko

2018-04-01

Younger, active patients who undergo total hip arthroplasty (THA) have increasing needs for wider range of motion and improved stability of the joint. Therefore, bearing materials having not only higher wear resistance but also mechanical strength are required. Carbon fiber-reinforced poly(ether ether ketone) (CFR-PEEK) is known as a super engineering plastic that has great mechanical strength. In this study, we focused on poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC)-grafted CFR-PEEK and investigated the effects of PMPC grafting and the femoral heads materials on the wear properties of CFR-PEEK liners. Compared with untreated CFR-PEEK, the PMPC-grafted CFR-PEEK surface revealed higher wettability and lower friction properties under aqueous circumstances. In the hip simulator wear test, wear particles generated from the PMPC-grafted CFR-PEEK liners were fewer than those of the untreated CFR-PEEK liners. There were no significant differences in the size and the morphology of the wear particles between the differences of PMPC-grafting and the counter femoral heads. Zirconia-toughened alumina (ZTA) femoral heads had significantly smoother surfaces compared to cobalt-chromium-molybdenum alloy femoral heads after the hip simulator test. Thus, we conclude that the bearing combination of the PMPC-grafted CFR-PEEK liner and ZTA head is expected to be a lifelong bearing interface in THA. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1028-1037, 2018. © 2017 Wiley Periodicals, Inc.

Wear mechanisms in powder metallurgy high speed steels matrix composites

International Nuclear Information System (INIS)

Gordo, E.; Martinez, M. A.; Torralba, J. M.; Jimenez, J. A.

2001-01-01

The development of metal matrix composites has a major interest for automotive and cutting tools industries since they possess better mechanical properties and wear resistance than corresponding base materials. One of the manufacturing methods for these materials includes processing by powder metallurgy techniques. in this case, blending of both, base material and reinforcement powders constitute the most important process in order to achieve a homogeneous distribution of second phase particles. in the present work, composite materials of M3/2 tool steel reinforced with 2.5,5 and 8 vol% of niobium carbide have been prepared. In order to ensure a homogeneous mix, powders of both materials were mixed by dry high-energy mechanical milling at 200 r.p.m. for 40 h. After a recovering annealing, two routes for consolidate were followed die pressing and vacuum sintering, and hot isostatic pressing (HIP). Pin-on-disc tests were carried out to evaluate wear behaviour in all the materials. Results show that ceramic particles additions improve wear resistance of base material. (Author) 9 refs

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

Science.gov (United States)

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

2017-11-01

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

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

Science.gov (United States)

Çakir, Fatih Hayati; Çelik, Osman Nuri

2017-09-01

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

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.

Effect of distribution of striated laser hardening tracks on dry sliding wear resistance of biomimetic surface

Science.gov (United States)

Su, Wei; Zhou, Ti; Zhang, Peng; Zhou, Hong; Li, Hui

2018-01-01

Some biological surfaces were proved to have excellent anti-wear performance. Being inspired, Nd:YAG pulsed laser was used to create striated biomimetic laser hardening tracks on medium carbon steel samples. Dry sliding wear tests biomimetic samples were performed to investigate specific influence of distribution of laser hardening tracks on sliding wear resistance of biomimetic samples. After comparing wear weight loss of biomimetic samples, quenched sample and untreated sample, it can be suggested that the sample covered with dense laser tracks (3.5 mm spacing) has lower wear weight loss than the one covered with sparse laser tracks (4.5 mm spacing); samples distributed with only dense laser tracks or sparse laser tracks (even distribution) were proved to have better wear resistance than samples distributed with both dense and sparse tracks (uneven distribution). Wear mechanisms indicate that laser track and exposed substrate of biomimetic sample can be regarded as hard zone and soft zone respectively. Inconsecutive striated hard regions, on the one hand, can disperse load into small branches, on the other hand, will hinder sliding abrasives during wear. Soft regions with small range are beneficial in consuming mechanical energy and storing lubricative oxides, however, soft zone with large width (>0.5 mm) will be harmful to abrasion resistance of biomimetic sample because damages and material loss are more obvious on surface of soft phase. As for the reason why samples with even distributed bionic laser tracks have better wear resistance, it can be explained by the fact that even distributed laser hardening tracks can inhibit severe worn of local regions, thus sliding process can be more stable and wear extent can be alleviated as well.

Potential countersample materials for in vitro simulation wear testing.

Science.gov (United States)

Shortall, Adrian C; Hu, Xiao Q; Marquis, Peter M

2002-05-01

Any laboratory investigation of the wear resistance of dental materials needs to consider oral conditions so that in vitro wear results can be correlated with in vivo findings. The choice of the countersample is a critical factor in establishing the pattern of tribological wear and in achieving an efficient in vitro wear testing system. This research investigated the wear behavior and surface characteristics associated with three candidate countersample materials used for in vitro wear testing in order to identify a possible suitable substitute for human dental enamel. Three candidate materials, stainless steel, steatite and dental porcelain were evaluated and compared to human enamel. A variety of factors including hardness, wear surface evolution and frictional coefficients were considered, relative to the tribology of the in vivo situation. The results suggested that the dental porcelain investigated bore the closest similarity to human enamel of the materials investigated. Assessment of potential countersample materials should be based on the essential tribological simulation supported by investigations of mechanical, chemical and structural properties. The selected dental porcelain had the best simulating ability among the three selected countersample materials and this class of material may be considered as a possible countersample material for in vitro wear test purposes. Further studies are required, employing a wider range of dental ceramics, in order to optimise the choice of countersample material for standardized in vitro wear testing.

Wet Slurry Abrasion Tests of Ceramic Coatings Deposited by Water-Stabilized Plasma Spraying

Czech Academy of Sciences Publication Activity Database

Nohava, Jiří

2003-01-01

Roč. 48, č. 2 (2003), s. 203-214 ISSN 0001-7043 R&D Projects: GA ČR GA106/01/0094 Institutional research plan: CEZ:AV0Z2043910 Keywords : plasma spraying, wear resistence, ceramic coating Subject RIV: BL - Plasma and Gas Discharge Physics

Advanced ceramic material for high temperature turbine tip seals

Science.gov (United States)

Solomon, N. G.; Vogan, J. W.

1978-01-01

Ceramic material systems are being considered for potential use as turbine blade tip gas path seals at temperatures up to 1370 1/4 C. Silicon carbide and silicon nitride structures were selected for study since an initial analysis of the problem gave these materials the greatest potential for development into a successful materials system. Segments of silicon nitride and silicon carbide materials over a range of densities, processed by various methods, a honeycomb structure of silicon nitride and ceramic blade tip inserts fabricated from both materials by hot pressing were tested singly and in combination. The evaluations included wear under simulated engine blade tip rub conditions, thermal stability, impact resistance, machinability, hot gas erosion and feasibility of fabrication into engine components. The silicon nitride honeycomb and low-density silicon carbide using a selected grain size distribution gave the most promising results as rub-tolerant shroud liners. Ceramic blade tip inserts made from hot-pressed silicon nitride gave excellent test results. Their behavior closely simulated metal tips. Wear was similar to that of metals but reduced by a factor of six.

Alumina-zirconium ceramics synthesis by selective laser sintering/melting

International Nuclear Information System (INIS)

Shishkovsky, I.; Yadroitsev, I.; Bertrand, Ph.; Smurov, I.

2007-01-01

In the present paper, porous refractory ceramics synthesized by selective laser sintering/melting from a mixture of zirconium dioxide, aluminum and/or alumina powders are subjected to optical metallography and X-ray analysis to study their microstructure and phase composition depending on the laser processing parameters. It is shown that high-speed laser sintering in air yields ceramics with dense structure and a uniform distribution of the stabilizing phases. The obtained ceramic-matrix composites may be used as thermal and electrical insulators and wear resistant coating in solid oxide fuel cells, crucibles, heating elements, medical tools. The possibility to reinforce refractory ceramics by laser synthesis is shown on the example of tetragonal dioxide of zirconium with hardened micro-inclusion of Al 2 O 3 . By applying finely dispersed Y 2 O 3 powder inclusions, the type of the ceramic structure is significantly changed

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

CERN Document Server

American Society for Testing and Materials. Philadelphia

2005-01-01

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

Studies of valve lifter for automotive heavy duty diesel engine by ceramic materials. I. Development of ceramic-metal joint by brazing method

Energy Technology Data Exchange (ETDEWEB)

Yun, H W [Technical Centre of KIA-ASIA MOTORS (Korea, Republic of); Han, I S [Korea Institute of Energy Research, Tajeon (Korea, Republic of); Lim, Y S; Chung, Y J [Myong Ji University (Korea, Republic of)

1998-02-01

Continuously contacting with camshaft, the face of Valve Lifter, made of cast iron, brings about abnormal wear such as unfair wear or early wear because it is heavily loaded in the valve train system as the engine gets more powered. This abnormal sear becomes a defect namely over-clearance when the valve is lifting so that the fuel gas imperfectly combusted by unsuitable open or close action of engine valve in the combustion chamber. The imperfect combustion, in the end, results in the major causes of air pollution and decrease of the engine output. Consequently, to prevent this wear, this study was to develop the valve lifter which is joined by brazing process with SCM435H and a tip by manufacturing the face as a superhardened ceramics alloy which has high wear resistance. Having the excellent surface hardness with Hv1100-1200, the sintered body developed with superhardened alloy(WC) can endure the severe face loading in the valve train system. We experienced with various brazing alloys and obtained the excellent joining strength to the joint had 150 MPa shear strength. Interface analysis and microstructure in a joint were examined through SEM and EDS, Optical microscope. Also, 2,500 hours, high speed(3,000{approx}4,000 rpm) and continuous (1step 12hr) engine dynamo testing was carried out to the casting valve lifter and ceramics-metal joint valve lifter so that the abnormal wears were compared and evaluated.

Microstructure and corrosive wear resistance of plasma sprayed Ni-based coatings after TIG remelting

Science.gov (United States)

Tianshun, Dong; Xiukai, Zhou; Guolu, Li; Li, Liu; Ran, Wang

2018-02-01

Ni based coatings were prepared on steel substrate by means of plasma spraying, and were remelted by TIG (tungsten inert gas arc) method subsequently. The microstructure, microhardness, electrochemical corrosion and corrosive wear resistance under PH = 4, PH = 7 and PH = 10 conditions of the coatings before and after remelting were investigated. The results showed that the TIG remelting obviously reduced the defects and dramatically decreased the coating’s porosity from 7.2% to 0.4%. Metallurgical bonding between the remelted coating and substrate was achieved. Meanwhile, the phase compositions of as-sprayed coating were γ-Ni, Mn5Si2 and Cr2B, while the phase compositions of the remelting coating were Fe3Ni, Cr23C6, Cr2B and Mn5Si2. The microhardness of the coating decreased from 724 HV to 608 HV, but the fracture toughness enhanced from 2.80 MPa m1/2 to 197.3 MPa m1/2 after remelting. After corrosive wear test, the average wear weight loss and 3D morphology of wear scar of two coatings indicated that the wear resistance of the remelted coating was remarkably higher than that of as-sprayed coating. Therefore, TIG remelting treatment was a feasible method to improve the coating’s microstructure and enhance its corrosive wear resistance.

Mixture for producing fracture-resistant, fiber-reinforced ceramic material by microwave heating

Science.gov (United States)

Meek, T.T.; Blake, R.D.

1985-04-03

A fracture-resistant, fiber-reinforced ceramic substrate is produced by a method which involves preparing a ceramic precursor mixture comprising glass material, a coupling agent, and resilient fibers, and then exposing the mixture to microwave energy. The microwave field orients the fibers in the resulting ceramic material in a desired pattern wherein heat later generated in or on the substrate can be dissipated in a desired geometric pattern parallel to the fiber pattern. Additionally, the shunt capacitance of the fracture-resistant, fiber-reinforced ceramic substrate is lower which provides for a quicker transit time for electronic pulses in any conducting pathway etched into the ceramic substrate.

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.

The Particle Distribution in Liquid Metal with Ceramic Particles Mould Filling Process

Science.gov (United States)

Dong, Qi; Xing, Shu-ming

2017-09-01

Adding ceramic particles in the plate hammer is an effective method to increase the wear resistance of the hammer. The liquid phase method is based on the “with the flow of mixed liquid forging composite preparation of ZTA ceramic particle reinforced high chromium cast iron hammer. Preparation method for this system is using CFD simulation analysis the particles distribution of flow mixing and filling process. Taking the 30% volume fraction of ZTA ceramic composite of high chromium cast iron hammer as example, by changing the speed of liquid metal viscosity to control and make reasonable predictions of particles distribution before solidification.

Grain size dependence of wear in ceramics

International Nuclear Information System (INIS)

Wu, C.C.; Rice, R.W.; Johnson, D.; Platt, B.A.

1985-01-01

Pin-On-Disk (POD), microwear tests of Al 2 O 3 , MgO, MgAl 2 O 4 , and ZrO 2 , most being dense and essentially single phase, showed the reciprocal of wear following a hall-petch type relationship. However, extrapolation to infinite grain size always gave a lower intercept than most or all single-crystal values; in particular, Al 2 O 3 data projects to a negative intercept. Initial macro wear tests of some of the same Al 2 O 3 materials also indicate a hall-petch type grain-size dependence, but with a greatly reduced grain-size dependence, giving a positive hall-petch intercept. Further, the macrowear grain-size dependence appears to decrease with increased wear. It is argued that thermal expansion anisotropy (of Al 2 O 3 ) significantly affects the grain size dependence of POD wear, in particular, giving a negative intercept, while elastic anisotropy is suggested as a factor in the grain-size dependence of the cubic (MgO, MgAl 2 O 4 , and ZrO 2 ) materials. The reduced grain-size dependence in the macrowear tests is attributed to overlapping wear tracks reducing the effects of enhanced wear damage, e.g., from elastic and thermal expansion anisotropies

Strength and wear resistance of a dental glass-ionomer cement with a novel nanofilled resin coating.

Science.gov (United States)

Lohbauer, Ulrich; Krämer, Norbert; Siedschlag, Gustavo; Schubert, Edward W; Lauerer, Brigitte; Müller, Frank A; Petschelt, Anselm; Ebert, Johannes

2011-04-01

To evaluate the influence of different resin coating protocols on the fracture strength and wear resistance of a commercial glass-ionomer cement (GIC). A new restorative concept [Equia (GC Europe)] has been introduced as a system application consisting of a condensable GIC (Fuji IX GP Extra) and a novel nanofilled resin coating material (G-Coat Plus). Four-point fracture strength (FS, 2 x 2 x 25 mm, 14-day storage, distilled water, 37 degrees C) were produced and measured from three experimental protocols: no coating GIC (Group 1), GIC coating before water contamination (Group 2), GIC coating after water contamination (Group 3). The strength data were analyzed using Weibull statistics. Three-body wear resistance (Group 1 vs. Group 2) was measured after each 10,000 wear cycles up to a total of 200,000 cycles using the ACTA method. GIC microstructure and interfaces between GIC and coating materials were investigated under SEM and CLSM. The highest FS of 26.1 MPa and the most homogenous behavior (m = 7.7) has been observed in Group 2. The coated and uncoated GIC showed similar wear resistance until 90,000 cycles. After 200,000 wear cycles, the coated version showed significantly higher wear rate (ANOVA, P< 0.05). The coating protocol has been shown to determine the GIC fracture strength. Coating after water contamination and air drying is leading to surface crack formation thus significantly reducing the FS. The resin coating showed a proper sealing of GIC surface porosities and cracks. In terms of wear, the coating did not improve the wear resistance of the underlying cement as similar or higher wear rates have been measured for Group 1 versus Group 2.

Method for producing ceramic composition having low friction coefficient at high operating temperatures

Science.gov (United States)

Lankford, Jr., James

1988-01-01

A method for producing a stable ceramic composition having a surface with a low friction coefficient and high wear resistance at high operating temperatures. A first deposition of a thin film of a metal ion is made upon the surface of the ceramic composition and then a first ion implantation of at least a portion of the metal ion is made into the near surface region of the composition. The implantation mixes the metal ion and the ceramic composition to form a near surface composite. The near surface composite is then oxidized sufficiently at high oxidizing temperatures to form an oxide gradient layer in the surface of the ceramic composition.

Use of the Empress all-ceramic restoration system.

Science.gov (United States)

Goulet, M K

1997-01-01

New dental materials and techniques have been introduced in the past few years to fabricate aesthetic ceramic restorations with improved strength, biocompatibility, resistance to wear, and better fit. Aesthetic concerns and increasing demand for tooth-colored posterior restorations have led to a number of all-ceramic restorations such as IPS Empress (Ivoclar-Williams, Amherst, NY). The Empress system offers superior aesthetics and physical properties. New generation ceramics along with the current adhesive techniques have resulted in the ability to provide higher strength, therefore indicating crowns for posterior restorations as well. These materials are being used more frequently and in more extensive oral prosthetic rehabilitations such as the case that will be presented. We discuss the different properties and advantages of IPS Empress.

Design of Wear-Resistant Austenitic Steels for Selective Laser Melting

Science.gov (United States)

Lemke, J. N.; Casati, R.; Lecis, N.; Andrianopoli, C.; Varone, A.; Montanari, R.; Vedani, M.

2018-03-01

Type 316L stainless steel feedstock powder was modified by alloying with powders containing carbide/boride-forming elements to create improved wear-resistant austenitic alloys that can be readily processed by Selective Laser Melting. Fe-based alloys with high C, B, V, and Nb contents were thus produced, resulting in a microstructure that consisted of austenitic grains and a significant amount of hard carbides and borides. Heat treatments were performed to modify the carbide distribution and morphology. Optimal hard-phase spheroidization was achieved by annealing the proposed alloys at 1150 °C for 1 hour followed by water quenching. The total increase in hardness of samples containing 20 pct of C/B-rich alloy powder was of 82.7 pct while the wear resistance could be increased by a factor of 6.

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.

Laser melt injection of ceramic particles in metals : Processing, microstructure and properties

NARCIS (Netherlands)

Ocelík, V.; De Hosson, J.Th.M.

2010-01-01

The objective of this paper is to present an overview of the possibilities of the laser melt injection (LMI) methodology to enhance the surface of light-weighted metals by adding hard ceramic particles in the top layer, with the aim to enhance the wear resistance and to increase the hardness. In

Mechanical And Microstructural Evaluation Of A Wear Resistant Steel

International Nuclear Information System (INIS)

Santos, F.L.F. dos; Vieira, A.G.; Correa, E.C.S.; Pinheiro, I.P.

2010-01-01

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

Effect of power toothbrushing on simulated wear of dental cement margins.

Science.gov (United States)

Black, Marsha A; Bayne, Stephen C; Peterson, Charlotte A

2007-01-01

Power toothbrushes (PTBs), in combination with abrasive dentifrices, may encourage wear of dental cements at crown margins. The objective of this in vitro simulation was to control the clinical variables associated with PTB use and measure the potential side effects of PTBs with mild and abrasive dentifrices. Four PTBs ( Braun-Oral-B-Professional Care at 150 g brushing force, Sonicare-Elite at 90 g, Colgate-Actibrush at 200 g and Crest-Spinbrush-Pro at 250 g) and 2 dentifrices mixed 1:1 with tap water (Mild= Colgate-Total, Colgate-Palmolive; Abrasive= Close-up, Chesebrough-Ponds) versus tap water alone (control) were used to abrade 2 cements (Fleck's Mizzy Zinc Phosphate [ZP]; 3M-ESPE Unicem universal cement [UC]) using cement-filled slots (160 m wide) cut into wear-resistant ceramic blocks. A custom fixture controlled PTB/block alignment, PTB loads, and other testing variables. Wear was measured (3 profilometer traces/slot, 5 slots/block/group, baseline to 5-year differences) and analyzed (3-way ANOVA, p PTBs and both dentifrices. Brushing with water showed no effects (pPTBs. Pooled 5y-wear levels for ZP for both dentifrices approximately 21 microm /5y) were similar to values for current-day posterior composite materials. Combinations of PTBs with mild and abrasive dentifrices produced significant wear with ZP but not UC; thus, resin-composite cements seem to represent a better choice for wear resistance.

Ceramic heat exchangers. (Latest citations from the US Patent bibliographic file with exemplary claims). Published Search

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-02-01

The bibliography contains citations of selected patents concerning the use of ceramic materials in the manufacture of industrial heat exchangers. The focus is on ceramics that display resistance to high temperature corrosion, abrasion, wear, and thermal shock. The design and fabrication of rotary, regenerative, and recuperative heat exchangers are discussed. Ceramic heat exchangers for uses in gas turbines, waste heat recovery equipment, and central heating systems are described. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

Ceramic heat exchangers. (Latest citations from the US Patent bibliographic file with exemplary claims). Published Search

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-04-01

The bibliography contains citations of selected patents concerning the use of ceramic materials in the manufacture of industrial heat exchangers. The focus is on ceramics that display resistance to high temperature corrosion, abrasion, wear, and thermal shock. The design and fabrication of rotary, regenerative, and recuperative heat exchangers are discussed. Ceramic heat exchangers for uses in gas turbines, waste heat recovery equipment, and central heating systems are described. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

Determination of metallo-organic and particulate wear metals in lubricating oils associated with hybrid ceramic bearings by inductively coupled plasma mass spectrometry

Science.gov (United States)

Russell, Robin Ann

It is possible to increase both the performance and operating environment of jet engines by using hybrid ceramic bearings. Our laboratory is concerned with investigating lubricating fluids for wear metals associated with silicon nitride ball bearings and steel raceways. Silicon nitride is characterized by low weight, low thermal expansion, high strength, and corrosion resistance. These attributes result in longer engine lifetimes than when metallic ball bearings are used. Before the routine use of ceramic ball bearings can be realized, the wear mechanisms of the materials should be thoroughly understood. One important variable in determining wear degradation is the concentration of metal present in the lubricating oils used with the bearings. A complete method for analyzing used lubricating oils for wear metal content must accurately determine all metal forms present. Oil samples pose problems for routine analysis due to complex organic matrices. Nebulizing these types of samples into an Inductively Coupled Plasma - Mass Spectrometer introduces many problems including clogging of the sample cone with carbon and increasing interferences. In addition, other techniques such as Atomic Absorption Spectrometry and Atomic Emission Spectrometry are particle size dependent. They are unable to analyze particles greater than 10 mum in size. This dissertation describes a method of analyzing lubricating oils for both metallo-organic and particulate species by ICP-MS. Microwave digestion of the oil samples eliminates the need for elaborate sample introduction schemes as well as the use of a modified carrier gas. Al, Cr, Fe, Mg, Mo, Ni, Ti, and Y have been determined in both aqueous and organic media. Metallo-organic solutions of these metals were successfully digested, nebulized into the ICP, and the singly charged ions measured by mass spectrometry. Metal particulates in oil matrices have also been quantitatively determined by the above method. Linear analytical curves were

Correlation of microstructure and wear resistance of molybdenum blend coatings fabricated by atmospheric plasma spraying

International Nuclear Information System (INIS)

Hwang, Byoungchul; Lee, Sunghak; Ahn, Jeehoon

2004-01-01

The correlation of microstructure and wear resistance of various molybdenum blend coatings applicable to automotive parts was investigated in this study. Five types of spray powders, one of which was pure molybdenum powder and the others were blends of brass, bronze, and aluminum alloy powders with molybdenum powder, were deposited on a low-carbon steel substrate by atmospheric plasma spraying (APS). Microstructural analysis of the coatings showed that they consisted of a curved lamellar structure formed by elongated splats, with hard phases that formed during spraying being homogeneously distributed in the molybdenum matrix. The wear test results revealed that the blend coatings showed better wear resistance than the pure molybdenum coating because they contained a number of hard phases. In particular, the molybdenum coating blended with bronze and aluminum alloy powders and the counterpart material showed an excellent wear resistance due to the presence of hard phases, such as CuAl 2 and Cu 9 Al 4 . In order to improve overall wear properties for the coating and the counterpart material, appropriate spray powders should be blended with molybdenum powders to form hard phases in the coatings

Synthesis, Mechanical Behavior, and Multi-Scale Tribological Performance of Carbon Nanoparticle Reinforced Ceramic Composites

Science.gov (United States)

Nieto, Andy

This dissertation investigates the effects of carbon nanoparticles on the synthesis, mechanical behavior, and tribological performance of ceramic based composites. Specifically graphene Nanoplatelet (GNP) reinforced Al 2O3 and nanodiamond (ND) reinforced WC-Co systems are investigated. Carbon based nanoparticles such as GNPs and NDs are ideal reinforcements for ceramic based composites because of their unique functional and mechanical properties. GNPs have exceptional mechanical properties such as yield strength and elastic modulus, along with superb functional properties such as thermal conductivity and electrical conductivity. NDs possess the highest hardness of any materials, very high elastic modulus, and have a very high thermal conductivity. GNPs are demonstrated to affect the sintering of Al2O 3 matrix composites by wrapping around grains, inhibiting diffusion, and thereby suppressing grain growth. High applied pressures (90 MPa) during sintering are observed to exacerbate grain growth suppression, while promoting attainment of fully dense ceramic composites. Higher applied pressures facilitate the wrapping of GNPs around grains, which promotes the onset of GNP induced grain growth suppression. Grain growth suppression compensates for the decreased hardness induced by low strength of the GNPs phase along the c-axis direction. GNPs enhanced the toughness and wear resistance of the nanocomposites by 21% and 39%, respectively, due to the intrinsic energy dissipating mechanisms such as GNP sheet kinking and sliding and GNP induced phenomena such as micro-cracking and crack bridging. The addition of ND affects the deposition of thermally sprayed coatings. Porosity increased in samples deposited by high velocity oxyacetylene flame spray (HVOF) and decreased in samples deposited by air plasma spray (APS). NDs are believed to inhibit solid state diffusion during splat impact, in the low thermal energy and high kinetic energy HVOF process. The high thermal

Study of Stainless Steel Resistance in Conditions of Tribocorrosion Wear

Directory of Open Access Journals (Sweden)

Goran Rozing

2015-07-01

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

Enhancing wear resistance of working bodies of grinder through lining crushed material

Science.gov (United States)

Romanovich, A. A.; Annenko, D. M.; Romanovich, M. A.; Apukhtina, I. V.

2018-03-01

The article presents the analysis of directions of increasing wear resistance of working surfaces of rolls. A technical solution developed at the level of the invention is proposed, which is simple to implement in production conditions and which makes it possible to protect the roll surface from heavy wear due to surfacing of wear-resistant mesh material, cells of which are filling with grinding material in the process of work. Retaining them enables one to protect the roll surface from wear. The paper dwells on conditions of pressing materials in cells of eccentric rolls on the working surface with a grid of rectangular shape. The paper presents an equation for calculation of the cell dimension that provides the lining of the working surface by a mill material with respect to its properties. The article presents results of comparative studies on the grinding process of a press roller grinder (PRG) between rolls with and without a fusion-bonded mesh. It is clarified that the lining of rolls working surface slightly reduces the quality of the grinding, since the material thickness in the cell is small and has a finely divided and compacted structure with high strength.

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

Directory of Open Access Journals (Sweden)

A. Vencl

2015-09-01

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

New Observations on High-Speed Machining of Hardened AISI 4340 Steel Using Alumina-Based Ceramic Tools

Directory of Open Access Journals (Sweden)

Mohamed Shalaby

2018-05-01

Full Text Available High-speed machining (HSM is used in industry to improve the productivity and quality of the cutting operations. In this investigation, pure alumina ceramics with the addition of ZrO2, and mixed alumina (Al2O3 + TiC tools were used in the dry hard turning of AISI 4340 (52 HRC at different high cutting speeds of 150, 250, 700 and 1000 m/min. It was observed that at cutting speeds of 150 and 250 m/min, pure alumina ceramic tools had better wear resistance than mixed alumina ones. However, upon increasing the cutting speed from 700 to 1000 m/min, mixed alumina ceramic tools outperformed pure ceramic ones. Scanning electron microscopy (SEM and X-ray photoelectron spectroscopy (XPS were used to investigate the worn cutting edges and analyze the obtained results. It was found that the tribo-films formed at the cutting zone during machining affected the wear resistances of the tools and influenced the coefficient of friction at the tool-chip interface. These observations were confirmed by the chip compression ratio results at different cutting conditions. Raising cutting speed to 1000 m/min corresponded to a remarkable decrease in cutting force components in the dry hard turning of AISI 4340 steel.

Composite Coatings of Alumina-based Ceramics and Stainless Steel Manufactured by Plasma Spraying

Czech Academy of Sciences Publication Activity Database

Ctibor, Pavel; Ageorges, H.; Neufuss, Karel; Zahálka, F.

2009-01-01

Roč. 15, č. 2 (2009), s. 108-114 ISSN 1392-1320 R&D Projects: GA AV ČR 1QS200430560 Institutional research plan: CEZ:AV0Z20430508 Keywords : Cermet * plasma spraying * microstructure * elastic modulus * wear resistance Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 0.299, year: 2009 http://internet.ktu.lt/en/science/journals/medz/medz0-97.html#Composite_Coatings_

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

Oxidized zirconium on ceramic; Catastrophic coupling.

Science.gov (United States)

Ozden, V E; Saglam, N; Dikmen, G; Tozun, I R

2017-02-01

Oxidized zirconium (Oxinium™; Smith & Nephew, Memphis, TN, USA) articulated with polyethylene in total hip arthroplasty (THA) appeared to have the potential to reduce wear dramatically. The thermally oxidized metal zirconium surface is transformed into ceramic-like hard surface that is resistant to abrasion. The exposure of soft zirconium metal under hard coverage surface after the damage of oxidized zirconium femoral head has been described. It occurred following joint dislocation or in situ succeeding disengagement of polyethylene liner. We reported three cases of misuse of Oxinium™ (Smith & Nephew, Memphis, TN, USA) heads. These three cases resulted in catastrophic in situ wear and inevitable failure although there was no advice, indication or recommendation for this use from the manufacturer. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Hardness of ion implanted ceramics

International Nuclear Information System (INIS)

Oliver, W.C.; McHargue, C.J.; Farlow, G.C.; White, C.W.

1985-01-01

It has been established that the wear behavior of ceramic materials can be modified through ion implantation. Studies have been done to characterize the effect of implantation on the structure and composition of ceramic surfaces. To understand how these changes affect the wear properties of the ceramic, other mechanical properties must be measured. To accomplish this, a commercially available ultra low load hardness tester has been used to characterize Al 2 O 3 with different implanted species and doses. The hardness of the base material is compared with the highly damaged crystalline state as well as the amorphous material

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

Science.gov (United States)

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

2012-02-01

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

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

International Nuclear Information System (INIS)

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

2006-01-01

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

Effects of Ti and TiC ceramic powder on laser-cladded Ti–6Al–4V in situ intermetallic composite

International Nuclear Information System (INIS)

Ochonogor, O.F.; Meacock, C.; Abdulwahab, M.; Pityana, S.; Popoola, A.P.I.

2012-01-01

Highlights: ► The wear resistance of the laser clad surfaces was enhanced significantly with fifteen-folds wear rate reduction. ► Micro-hardness of the clad zones indicated a significant improvement of over two-folds greater than the substrate. ► Microstructures showed fine crystal grains distribution of ceramic particles that formed interstitial carbides in the titanium matrix composites. - Abstract: Titanium metal matrix composite (MMCs) was developed on titanium alloy (Ti–6Al–4V) substrate with the aim of improving the hardness and wear properties by laser cladding technique using a Rofin Sinar 4 kW Nd: YAG laser. Wear investigations were carried out with the aid of three body abrasion tester. The resultant microstructure show homogeneous distribution of TiC particles free from cracks and pores. Multiple track deposited systems with 50% overlap revealed micro-hardness increase from 357.3 HV 0.1 for the substrate reaching a peak as high as 922.2 HV 0.1 for 60%Ti + 40%TiC and the least 665.3 HV 0.1 for 80%Ti + 20%TiC MMCs. The wear resistance of the materials improved significantly, indicating a fifteen-fold wear rate reduction due to the proper distribution of ceramic particles thereby forming interstitial carbides as revealed by the X-ray diffraction spectrum.

Effects of Ti and TiC ceramic powder on laser-cladded Ti-6Al-4V in situ intermetallic composite

Energy Technology Data Exchange (ETDEWEB)

Ochonogor, O.F. [Department of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria, X680 0001 (South Africa); Meacock, C. [Council for Scientific and Industrial Research, National Laser Centre, Pretoria (South Africa); Abdulwahab, M. [Department of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria, X680 0001 (South Africa); Pityana, S. [Department of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria, X680 0001 (South Africa); Council for Scientific and Industrial Research, National Laser Centre, Pretoria (South Africa); Popoola, A.P.I., E-mail: popoolaapi@tut.ac.za [Department of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria, X680 0001 (South Africa)

2012-12-15

Highlights: Black-Right-Pointing-Pointer The wear resistance of the laser clad surfaces was enhanced significantly with fifteen-folds wear rate reduction. Black-Right-Pointing-Pointer Micro-hardness of the clad zones indicated a significant improvement of over two-folds greater than the substrate. Black-Right-Pointing-Pointer Microstructures showed fine crystal grains distribution of ceramic particles that formed interstitial carbides in the titanium matrix composites. - Abstract: Titanium metal matrix composite (MMCs) was developed on titanium alloy (Ti-6Al-4V) substrate with the aim of improving the hardness and wear properties by laser cladding technique using a Rofin Sinar 4 kW Nd: YAG laser. Wear investigations were carried out with the aid of three body abrasion tester. The resultant microstructure show homogeneous distribution of TiC particles free from cracks and pores. Multiple track deposited systems with 50% overlap revealed micro-hardness increase from 357.3 HV{sub 0.1}for the substrate reaching a peak as high as 922.2 HV{sub 0.1} for 60%Ti + 40%TiC and the least 665.3 HV{sub 0.1} for 80%Ti + 20%TiC MMCs. The wear resistance of the materials improved significantly, indicating a fifteen-fold wear rate reduction due to the proper distribution of ceramic particles thereby forming interstitial carbides as revealed by the X-ray diffraction spectrum.

Fiscal 1997 achievement report. Research and development of synergy ceramics; 1997 nendo synergy ceramics no kenkyu kaihatsu seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

Research and development is conducted on two subjects, that is, 1) hyper organized structure control technology and 2) structural element control technology. In addition, joint research and development is conducted on the creation of new materials by hyper organized structure controlling, hyper organized structure controlling for ceramics by a structurization reaction process, designing of precursors to ceramics, and the hyper organized structure control for ceramics by nanostructure process control. The joint research and development endeavors further deal with re-entrusted projects which involve researches on sintered structure control by powdery particulate structure control; dynamic process of synergy ceramics; oxynitride liquids, glasses, and glass-ceramics; and multifunctional ceramic laminates for engineering applications. Under subject 1), researches are made on the development of precursors into ceramics by utilizing chemical reactions of organic metal compounds, and analyses are conducted into the effects, exerted by the molecular structures of precursors and the conditions of a reaction for their development into ceramics, on the microstructures and various properties of the ceramics to be composed. Under subject 2), high strength, great hardness, and high resistance to wear are realized by allowing the precipitation of nano-particulates in crystals of a fine and very compact sintered body of alumina. (NEDO)

Study of the effect of nano surface morphology on the stain-resistant property of ceramic tiles

International Nuclear Information System (INIS)

Pan, S P; Hung, J K; Liu, Y T

2014-01-01

In this study, six types of commercially available ceramic tiles, including nano-structured ceramic tiles and regular ceramic tiles, were selected to investigate the effect of surface morphology on their stain-resistant property. The stain-resistant efficiencies of various ceramic tiles with nano-size surface were measured in order to determine the appropriate method for testing ceramic tiles with nano-structure surface

Laser cladding of copper with molybdenum for wear resistance enhancement in electrical contacts

International Nuclear Information System (INIS)

Ng, K.W.; Man, H.C.; Cheng, F.T.; Yue, T.M.

2007-01-01

Laser cladding of Mo on Cu has been attempted with the aim of enhancing the wear resistance and hence increasing the service life of electrical contacts made of Cu. In order to overcome the difficulties arising from the large difference in thermal properties and the low mutual solubility between Cu and Mo, Ni was introduced as an intermediate layer between Mo and Cu. The Ni and Mo layers were laser clad one after the other to form a sandwich layer of Mo/Ni/Cu. Excellent bonding between the clad layer and the Cu substrate was ensured by strong metallurgical bonding. The hardness of the surface of the clad layer is seven times higher than that of the Cu substrate. Pin-on-disc wear tests consistently showed that the abrasive wear resistance of the clad layer was also improved by a factor of seven as compared with untreated Cu substrate. The specific electrical contact resistance of the clad surface was about 5.6 x 10 -7 Ω cm 2

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-04-13

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

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

International Nuclear Information System (INIS)

Dave, V.; Rao, G. P.; Tiwari, G. S.; Sanger, A.; Kumar, A.; Chandra, R.

2016-01-01

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

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

Science.gov (United States)

Dave, V.; Rao, G. P.; Tiwari, G. S.; Sanger, A.; Kumar, A.; Chandra, R.

2016-04-01

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

What every surgeon should know about Ceramic-on-Ceramic bearings in young patients

OpenAIRE

Hernigou, Philippe; Roubineau, Fran?ois; Bouthors, Charlie; Flouzat-Lachaniette, Charles-Henri

2016-01-01

Based on the exceptional tribological behaviour and on the relatively low biological activity of ceramic particles, Ceramic-on-Ceramic (CoC) total hip arthroplasty (THA) presents significant advantages CoC bearings decrease wear and osteolysis, the cumulative long-term risk of dislocation, muscle atrophy, and head-neck taper corrosion. However, there are still concerns regarding the best technique for implantation of ceramic hips to avoid fracture, squeaking, and revision of ceramic hips with...

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.)

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

Preparation and photocatalytic activity of chemically-bonded phosphate ceramics containing TiO2

Science.gov (United States)

Martins, Monize Aparecida; de Lima, Bruna de Oliveira; Ferreira, Leticia Patrício; Colonetti, Emerson; Feltrin, Jucilene; De Noni, Agenor

2017-05-01

Titanium dioxide was incorporated into chemically-bonded phosphate ceramic for use as photocatalytic inorganic coating. The coatings obtained were applied to unglazed ceramic tiles and cured at 350 °C. The surfaces were characterized by photocatalytic activity, determined in aqueous medium, based on the degradation of methylene blue dye. The effects of the percentage of TiO2 and the thickness of the layer on the photocatalytic efficiency were evaluated. The influence of the incorporation of TiO2 on the consolidation of the phosphate matrix coating was investigated using the wear resistance test. The crystalline phases of the coatings obtained were determined by XRD. The microstructure of the surfaces was analyzed by SEM. The thermal curing treatment did not cause a phase transition from anatase to rutile. An increase in the photocatalytic activity of the coating was observed with an increase in the TiO2 content. The dye degradation indices ranged from 14.9 to 44.0%. The photocatalytic efficiency was not correlated with the thickness of the coating layer deposited. The resistance to wear decreased with an increase in the TiO2 content. Comparison with a commercial photocatalytic ceramic coating indicated that there is a range of values for the TiO2 contents which offer potential for photocatalytic applications.

Investigations on Wear Mechanisms of PVD Coatings on Carbides and Sialons

Directory of Open Access Journals (Sweden)

Staszuk M.

2017-12-01

Full Text Available The paper presents the results on the wear resistance of PVD coatings on cutting inserts made from sintered carbide and sialon ceramics. The exploitative properties of coatings in technological cutting trials were defined in the paper, which also examined the adhesion of coatings to the substrate, the thickness of the coating, and the microhardness. As a result, it was found that isomorphic coating with AlN-h phase of covalent interatomic bonds exhibits much better adhesion to the sialon substrate than isomorphic coating with titanium nitride TiN. These coatings assure the high wear resistance of the coated tools, and the high adhesion combined with the high microhardness and fine-grained structure assure an increase in the exploitative life of the coated tools. In the case of coatings on substrate made from sintered carbide, there was a significant influence on the properties of the tools coated with them as concerns the existence of the diffusion zone between the substrate and the coating.

Provision of wear resistance and fatigue strength of surfaces during electroerosive processing

Science.gov (United States)

Fedonin, O. N.; Syanov, S. Yu; Papikyan, A. M.

2018-03-01

This article is a generalization of the results of theoretical studies of the effect of erosion control regimes on the operational properties of mold-forming parts of molds. The main problem is the provision of wear resistance and fatigue strength in the electroerosion processing of these types of products. The analysis showed that the fatigue strength is affected by the processing regimes and the coefficient after the erosion treatment. The index of wear resistance is determined both by the treatment modes and by the physical-mechanical properties of the billet materials. To ensure the operational performance of products, it is necessary to establish the physical picture of the processing of complex profile parts by finding the optimum eroding regime.

Wear mechanisms of coated hardmetals

International Nuclear Information System (INIS)

Richter, V.

2001-01-01

In the paper several aspects of the wear mechanisms of coated hardmetals, ceramics and super-hard materials (CBN) in machining cast iron are discussed, with particular attention being given to high-speed machining of different cast iron grades. The influence of machining parameters, microstructure, composition and mechanical and chemical properties of the cutting tool and the work-piece material on wear are considered. (author)

Ion implantation and ion assisted coatings for wear resistance in metals

International Nuclear Information System (INIS)

Dearnaley, G.

1986-01-01

The implantation of electrically accelerated ions of chosen elements into the surface of material provides a method for improving surface properties such as wear resistance. High concentrations of nitrogen implanted into metals create obstacles to dislocation movement, and certain combinations of metallic and non-metallic species will also strengthen the surface. The process is best applied to situations involving mild abrasive wear and operating temperatures that are not too high. Some dramatic increases in life have been reported under such favourable conditions. A more recent development has been the combination of a thin coating with reactive ion bombardment designed to enhance adhesion by ion mixing at the interface and so provide hardness by the formation of finely dispersed nitrides, including cubic boron nitride. These coatings often possess vivid and decorative colours as an added benefit. Developments in the equipment for industrial ion implantation now offer more attractive costs per unit area and a potentially greater throughput of work. A versatile group of related hard vacuum treatments is now emerging, involving the use of intense beams of nitrogen ions for the purpose of tailoring metal surfaces to resist wear. (author)

Improvement of wear-resistance of solid lubricants by ionic impact

DEFF Research Database (Denmark)

1993-01-01

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

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

Fiscal 1999 achievement report on regional consortium research and development project. Regional consortium on energy research in its 3rd year (Research and development of mezoscopic composite phase material based on heat-/wear-resistant metal); 1999 nendo mezoscopic fukuso soshiki seigyo tainetsu taimamosei kinzokuki fukugo zairyo no kenkyu kaihatsu seika hokokusho. 3

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

Using an in-situ method, three kinds of Fe-C-Ni-Cr-Mo-Nb-based alloys are developed, whose strength is not less than 800MPa at 1073K. They exhibit, in a high-temperature erosion wear test, a wear resistance which is 2-3 times higher than that of conventional materials. When they are cast, wear-causing graphite precipitation is suppressed thanks to the cast iron coagulating in gaps in the ceramic formed into a net shape. It is also found that in this process the precipitation of cementites etc., which improves on the abrasion and wear characteristics, is accelerated and that the cementites etc. are finely dispersed for improvement on the brake (brake block) characteristics. Tentatively produced brake blocks are tested for performance at the Railway Technical Research Institute. The new materials are found to exhibit a wear resistance which is 2.2 times higher, and a braking capability 1.6 times better, than those of conventional materials. In the case of an Fe-50Cr-4.8C alloy produced by an MA (mechanical alloying) method, {alpha}-Fe is dispersed into M{sub 23}C{sub 6} for a remarkable improvement on the wear-resisting feature. A 10%TiC cermet exhibits a remarkably high wear resistance, that is, a transverse rupture strength of 1270MPa which is higher than that of a cast high-speed steel. (NEDO)

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

International Nuclear Information System (INIS)

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

2003-01-01

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

Study on the wear of TiN/Ti duplex and multilayer coatings in microabrasion tests

International Nuclear Information System (INIS)

Flores, M; De Las Heras, E; Ruelas, R; Rodriguez, E; Bautista, A; Pazos, L; Corengia, P

2008-01-01

Ionic nitriding, on steels, is used to harden the surface of components improving resistance to corrosion and wear and increasing the stress life. Duplex treatments are an alternative for resolving the limitations of very hard coatings on less hard substrates. In this case the duplex treatment consists of an ionic nitriding treatment followed by a single or multilayer coatings deposited by means of the PVD technique. This work presents the influence of the variation in the severity of contact on the kind of wear present in the microabrasion test used to measure the wear coefficient of duplex coatings, consisting of a layer nitrided by DC-pulsed plasma plus TiN coatings and multilayers of TiN/Ti deposited on non-nitrided and nitrided AISI 316L stainless steel and H13 steel. The severity of contact was modified by varying the charge (0.25 to 1 N). The abrasives used were a suspension of 0.1μm diameter diamond particles and a suspension of an average 5 μm diameter aluminum particles. The influence of the presence of relatively soft metallic layers on the determination of the wear coefficient was analyzed in the metal-ceramic multilayers. Two sphere revolving speeds of de 0.05 and 0.154 m/s were used on two microabrasion machines: one commercial and the other built in the UdeG laboratory. The wear marks were photographed and measured with an optic microscope. The value of the critical charge at which the transition occurs between the methods of wear of the substrates and the nitrited samples was determined. Resistance to the AISI 316L steel's microabrasive wear increases with the ionic nitriding treatment. The duplex coatings increase resistance to the wear from the nitrited samples. The wear resistance of the samples with multilayer coatings surpassed that of the duplex samples with multilayer coatings. The greater resistance of the multilayers may be explained by an increase in the resistance to the fracture and not by a increase in surface hardness. The transition

Wear resistance increase of the modified coatings, deposited in the beam of relativistic electrons

International Nuclear Information System (INIS)

Poletika, I.M.; Perovskaya, M.V.; Balushkina, M.A.

2015-01-01

The 1.5-3 mm thickness coatings have been obtained by vacuum - free electron beam cladding of tungsten carbide on low - carbon steel sub state. The coatings have an increased hardness but low wear resistance. Adding both nickel and titanium carbide to the tungsten carbide results in essentially improving the wear resistance of the coatings due to austenite-promoting effect of nickel and precipitation of fine Tic particles resulting in the formation of the final and nano grain structure. In the layer of weld one can find 30-100 nm grain - size structures. (authors)

Wear Resistance of 3D Printing Resin Material Opposing Zirconia and Metal Antagonists.

Science.gov (United States)

Park, Ji-Man; Ahn, Jin-Soo; Cha, Hyun-Suk; Lee, Joo-Hee

2018-06-20

3D printing offers many advantages in dental prosthesis manufacturing. This study evaluated the wear resistance of 3D printing resin material compared with milling and conventional resin materials. Sixty substrate specimens were prepared with three types of resin materials: 3D printed resin, milled resin, and self-cured resin. The 3D printed specimens were printed at a build angle of 0° and 100 μm layer thickness by digital light processing 3D printing. Two kinds of abraders were made of zirconia and CoCr alloy. The specimens were loaded at 5 kg for 30,000 chewing cycles with vertical and horizontal movements under thermocycling condition. The 3D printed resin did not show significant difference in the maximal depth loss or the volume loss of wear compared to the milled and the self-cured resins. No significant difference was revealed depending on the abraders in the maximal depth loss or the volume loss of wear. In SEM views, the 3D printed resin showed cracks and separation of inter-layer bonds when opposing the metal abrader. The results suggest that the 3D printing using resin materials provides adequate wear resistance for dental use.

Preparation of basalt-based glass ceramics

Directory of Open Access Journals (Sweden)

MIHOVIL LOGAR

2003-06-01

Full Text Available Local and conventional raw materials–massive basalt from the Vrelo locality on Kopaonik mountain–have been used as starting materials to test their suitability for the production of glass-ceramics. Crystallization phenomena of glasses of the fused basalt rocks were studied by X-ray phase analysis, optical microscopy and other techniques. Various heat treatments were used, and their influences, on controlling the microstructures and properties of the products were studied with the aim of developing high strength glass-ceramic materials. Diopside CaMg(SiO32 and hypersthene ((Mg,FeSiO3 were identifies as the crystalline phases. The final products contained considerable amounts of a glassy phase. The crystalline size was in range of 8–480 mm with plate or needle shape. Microhardness, crashing strength and wears resistence of the glass-ceramics ranged from 6.5–7.5, from 2000–6300 kg/cm2 and from 0.1–0.2 g/cm, respectively.

Performance evaluation of PCBN, coated carbide and mixed ceramic inserts in finish-turning of AISI D2 steel

Directory of Open Access Journals (Sweden)

M. Junaid Mir

2017-09-01

Full Text Available The present study compares the performance of three different cutting tools, viz., PCBN, mixed ceramic and coated carbide tool in finish turning of hardened D2 tool steel in terms of tool wear, surface roughness, and economic feasibility under dry cutting conditions. Results showed that tool life of PCBN inserts was better than mixed ceramic and coated carbide inserts. The flank wear of PCBN tools was observed to be lower than mixed ceramic and coated carbide inserts. The surface roughness achieved under all cutting conditions for mixed ceramic and coated-carbide inserts was comparable with that achieved with PCBN inserts and was below 1.6μm. Experimental results showed that the wear mechanism of ceramic tool is pre-dominantly abrasive wear at lower speeds and abrasive wear followed by adhesive wear at medium and higher speeds and for PCBN tools the dominant wear mechanism is abrasive wear and cratering at lower speeds followed by adhesive wear at higher speeds. For carbide tool the dominant wear mechanism was abrasive wear and cratering at lower speeds followed by adhesion and chipping at higher speeds. Obtained results revealed that PCBN tools can outperform both ceramic and carbide tools in terms of tool life under different machinability criteria used.

Assessment of exposures and potential risks to the US adult population from wear (attrition and abrasion) of gold and ceramic dental restorations.

Science.gov (United States)

Richardson, G Mark; Clemow, Scott R; Peters, Rachel E; James, Kyle J; Siciliano, Steven D

2016-01-01

Little has been published on the chemical exposures and risks of dental restorative materials other than from dental amalgam and composite resins. Here we provide the first exposure and risk assessment for gold (Au) alloy and ceramic restorative materials. Based on the 2001-2004 US National Health and Nutrition Examination Survey (NHANES), we assessed the exposure of US adults to the components of Au alloy and ceramic dental restorations owing to dental material wear. Silver (Ag) is the most problematic component of Au alloy restorations, owing to a combination of toxicity and proportional composition. It was estimated that adults could possess an average of four tooth surfaces restored with Au alloy before exceeding, on average, the reference exposure level (REL) for Ag. Lithium (Li) is the most problematic component of dental ceramics. It was estimated that adults could possess an average of 15 tooth surfaces restored with ceramics before exceeding the REL for Li. Relative risks of chemical exposures from dental materials decrease in the following order: Amalgam>Au alloys>ceramics>composite resins.

Application of ceramics to the sliding seat of valve bridge; Valve bridge yodobu eno ceramics tekiyo

Energy Technology Data Exchange (ETDEWEB)

Matsui, T; Ono, T [Mitsubishi Motors Corp., Tokyo (Japan)

1997-10-01

For use in the valve train, using an OHV (over head valve) configuration. of a 4 valve diesel engine for trucks and buses; we developed a valve bridge, a component of a valve train, with a ceramic head that is made of silicon nitride(Si3N4) in contact with a rocker arm in order to reduce cost and improve wear resistance for further diesel engine emissions regulations. In order to evaluate the effect of this valve bridge, RIG tests and durability tests on actual engines were carried out. 7 figs., 2 tabs.

Ultra-high wear resistance of ultra-nanocrystalline diamond film: Correlation with microstructure and morphology

Science.gov (United States)

Rani, R.; Kumar, N.; Lin, I.-Nan

2016-05-01

Nanostructured diamond films are having numerous unique properties including superior tribological behavior which is promising for enhancing energy efficiency and life time of the sliding devices. High wear resistance is the principal criterion for the smooth functioning of any sliding device. Such properties are achievable by tailoring the grain size and grain boundary volume fraction in nanodiamond film. Ultra-nanocrystalline diamond (UNCD) film was attainable using optimized gas plasma condition in a microwave plasma enhanced chemical vapor deposition (MPECVD) system. Crystalline phase of ultra-nanodiamond grains with matrix phase of amorphous carbon and short range ordered graphite are encapsulated in nanowire shaped morphology. Film showed ultra-high wear resistance and frictional stability in micro-tribological contact conditions. The negligible wear of film at the beginning of the tribological contact was later transformed into the wearless regime for prolonged sliding cycles. Both surface roughness and high contact stress were the main reasons of wear at the beginning of sliding cycles. However, the interface gets smoothened due to continuous sliding, finally leaded to the wearless regime.

Tribology of ceramics and composites materials science perspective

CERN Document Server

Basu, Bikramjit

2011-01-01

This book helps students and practicing scientists alike understand that a comprehensive knowledge about the friction and wear properties of advanced materials is essential to further design and development of new materials. With important introductory chapters on the fundamentals, processing, and applications of tribology, the book then examines in detail the nature and properties of materials, the friction and wear of structural ceramics, bioceramics, biocomposites, and nanoceramics, as well as lightweight composites and the friction and wear of ceramics in a cryogenic environment.

Improvement of the Wear Resistance of Ferrous Alloys by Electroless Plating of Nickel

Science.gov (United States)

Kaleicheva, J. K.; Karaguiozova, Z.

2018-01-01

The electroless nickel (Ni) and composite nickel - nanodiamond (Ni+DND) coatings are investigated in this study. The method EFTTOM-NICKEL for electroless nickel plating with nanosized strengthening particles (DND 4-6 nm) is applied for the coating deposition. The coatings are deposited on ferrous alloys samples. The wear resistance of the coatings is performed by friction wear tests under 50-400 MPa loading conditions - in accordance with a Polish Standard PN-83/H-04302. The microstructure observations are made by optic metallographic microscope GX41 OLIMPUS and the microhardness is determined by Vickers Method. Tests for wear resistance, thickness and microhardness measurements of the coatings without heat treatment and heat treatment are performed. The heat treatment regime is investigated with the aim to optimize the thermal process control of the coated samples without excessive tempering of the substrate material. The surface fatigue failure is determined by contact fatigue test with the purpose to establish suitable conditions for production of high performance materials.

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)

Dry sliding wear behavior and corrosion resistance of NiCrBSi coating deposited by activated combustion-high velocity air fuel spray process

International Nuclear Information System (INIS)

Liu, Shenglin; Zheng, Xueping; Geng, Gangqiang

2010-01-01

NiCrBSi is a Ni-based superalloy widely used to obtain high wear and corrosion resistant coatings. This Ni-based alloy coating has been deposited onto 0Cr13Ni5Mo stainless steel using the AC-HVAF technique. The structure and morphologies of the Ni-based coatings were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectrometer (EDS). The wear resistance and corrosion resistance were studied. The tribological behaviors were evaluated using a HT-600 wear test rig. The wear resistance of the Ni-based coating was shown to be higher than that of the 0Cr13Ni5Mo stainless steel because Fe 3 B, with high hardness, was distributed in the coating so the dispersion strengthening in the Ni-based coating was obvious and this increased the wear resistance of the Ni-based coating in a dry sliding wear test. Under the same conditions, the worn volume of 0Cr13Ni5Mo stainless steel was 4.1 times greater than that of the Ni-based coating. The wear mechanism is mainly fatigue wear. A series of the electrochemical tests was carried out in a 3.5 wt.% NaCl solution in order to examine the corrosion behavior. The mechanisms for corrosion resistance are discussed.

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

Tribological characteristics of ceramic conversion treated NiTi shape memory alloy

International Nuclear Information System (INIS)

Ju, X; Dong, H

2007-01-01

NiTi shape memory alloys are very attractive for medical implants and devices (such as orthopaedic and orthodontic implants) and various actuators. However, wear is a major concern for such applications and a novel surface engineering process, ceramic conversion treatment, has recently been developed to address this problem. In this study, the tribological characteristics of ceramic conversion treated NiTi alloy have been systematically investigated under dry unidirectional wear, reciprocating-corrosion wear and fretting-corrosion wear condition. Based on the experimental results, the wear behaviour under different conditions is compared and wear mechanisms involved are discussed

Tribological characteristics of ceramic conversion treated NiTi shape memory alloy

Energy Technology Data Exchange (ETDEWEB)

Ju, X; Dong, H [Department of Metallurgy and Materials, School of Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

2007-09-21

NiTi shape memory alloys are very attractive for medical implants and devices (such as orthopaedic and orthodontic implants) and various actuators. However, wear is a major concern for such applications and a novel surface engineering process, ceramic conversion treatment, has recently been developed to address this problem. In this study, the tribological characteristics of ceramic conversion treated NiTi alloy have been systematically investigated under dry unidirectional wear, reciprocating-corrosion wear and fretting-corrosion wear condition. Based on the experimental results, the wear behaviour under different conditions is compared and wear mechanisms involved are discussed.

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

Directory of Open Access Journals (Sweden)

Sinan SEZEK

2017-02-01

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

Antagonist wear of monolithic zirconia crowns after 2 years.

Science.gov (United States)

Lohbauer, Ulrich; Reich, Sven

2017-05-01

The aim of this study was to evaluate the amount of wear on the antagonist occlusal surfaces of clinically placed monolithic zirconia premolar and molar crowns (LAVA Plus, 3M ESPE). Fourteen in situ monolithic zirconia crowns and their opposing antagonists (n = 26) are the subject of an ongoing clinical trial and have been clinically examined at baseline and after 24 months. Silicone impressions were taken and epoxy replicas produced for qualitative SEM analysis and quantitative analysis using optical profilometry. Based on the baseline replicas, the follow-up situation has been scanned and digitally matched with the initial topography in order to calculate the mean volume loss (in mm 3 ) as well as the mean maximum vertical loss (in mm) after 2 years in service. The mean volume loss for enamel antagonist contacts (n = 7) was measured to 0.361 mm 3 and the mean of the maximum vertical loss to 0.204 mm. The mean volume loss for pure ceramic contacts (n = 10) was measured to 0.333 mm 3 and the mean of the maximum vertical loss to 0.145 mm. The wear rates on enamel contacts were not significantly different from those measured on ceramic antagonists. Based on the limitations of this study, it can be concluded for the monolithic zirconia material LAVA Plus that the measured wear rates are in consensus with other in vivo studies on ceramic restorations. Further, that no significant difference was found between natural enamel antagonists and ceramic restorations as antagonists. The monolithic zirconia restorations do not seem to be affected by wear within the first 2 years. The monolithic zirconia crowns (LAVA Plus) show acceptable antagonist wear rates after 2 years in situ, regardless of natural enamel or ceramics as antagonist materials.

Borides - a new generation of highly resistant materials?

International Nuclear Information System (INIS)

Telle, R.

1988-01-01

High-duty ceramics are on advance in all sectors where materials with extremely good resistance to high temperatures and wear are required. The group of oxides, nitrides and carbides in use for quite a time now recently has been increased by the metal borides which offer among others economic advantages in certain applications. The drawbacks of these materials still to be reduced are their brittleness and susceptibility to oxidation and corrosion. Current research work on the thermodynamics of such systems, on the interaction between structure and properties, and on means to improve strength and resistance to wear are expected to soon open up new applications. (orig.) [de

Application of response surface methodology on investigating flank wear in machining hardened steel using PVD TiN coated mixed ceramic insert

Directory of Open Access Journals (Sweden)

Ashok Kumar Sahoo

2013-10-01

Full Text Available The paper presents the development of flank wear model in turning hardened EN 24 steel with PVD TiN coated mixed ceramic insert under dry environment. The paper also investigates the effect of process parameter on flank wear (VBc. The experiments have been conducted using three level full factorial design techniques. The machinability model has been developed in terms of cutting speed (v, feed (f and machining time (t as input variable using response surface methodology. The adequacy of model has been checked using correlation coefficients. As the determination coefficient, R2 (98% is higher for the model developed; the better is the response model fits the actual data. In addition, residuals of the normal probability plot lie reasonably close to a straight line showing that the terms mentioned in the model are statistically significant. The predicted flank wear has been found to lie close to the experimental value. This indicates that the developed model can be effectively used to predict the flank wear in the hard turning. Abrasion and diffusion has been found to be the dominant wear mechanism in machining hardened steel from SEM micrographs at highest parametric range. Machining time has been found to be the most significant parameter on flank wear followed by cutting speed and feed as observed from main effect plot and ANOVA study.

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.

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

Effect of Ni Addition on the Wear and Corrosion Resistance of Fe-20Cr-1.7C-1Si Hardfacing Alloy

International Nuclear Information System (INIS)

Lee, Sung Hoon; Kim, Ki Nam; Kim, Seon Jin

2011-01-01

In order to improve the corrosion resistance of Fe-20Cr-1.7C-1Si hardfacing alloy without a loss of wear resistance, the effect of Ni addition was investigated. As expected, the corrosion resistance of the alloy increased with increasing Ni concentration. The wear resistance of the alloy did not decrease, even though the hardness decreased, up to Ni concentration of 5 wt.%. This was attributed to the fact that the decrease in hardness was counterbalanced by the strain-induced martensitic transformation. The wear resistance of the alloy, however, decreased abruptly with increases of the Ni concentration over 5 wt.%.

Performance of ceramics in ring/cylinder applications

International Nuclear Information System (INIS)

Dufrane, K.F.; Glaeser, W.A.

1987-01-01

In support of the efforts to apply ceramics to advanced heat engines, a study is being performed of the performance of ceramics at the ring/cylinder interface of advanced (low heat rejection) engines. The objective of the study, managed by the Oak Ridge National Laboratory, is to understand the basic mechanisms controlling the wear of ceramics and thereby identify means for applying ceramics effectively. Attempts to operate three different zirconias, silicon carbide, silicon nitride, and plasma-sprayed ceramic coatings without lubrication have not been successful because of excessive friction and high wear rates. Silicon carbide and silicon nitride perform well at ambient temperatures with fully formulated mineral oil lubrication, but are limited to temperatures of 500F because of the lack of suitable liquid lubricants for higher temperatures

Absorption Voltages and Insulation Resistance in Ceramic Capacitors with Cracks

Science.gov (United States)

Teverovsky, Alexander

2016-01-01

Time dependence of absorption voltages (Vabs) in different types of low-voltage X5R and X7R ceramic capacitors was monitored for a maximum duration of hundred hours after polarization. To evaluate the effect of mechanical defects on Vabs, cracks in the dielectric were introduced either mechanically or by thermal shock. The maximum absorption voltage, time to roll-off, and the rate of voltage decrease are shown to depend on the crack-related leakage currents and insulation resistance in the parts. A simple model that is based on the Dow equivalent circuit for capacitors with absorption has been developed to assess the insulation resistance of capacitors. Standard measurements of the insulation resistance, contrary to the measurements based on Vabs, are not sensitive to the presence of mechanical defects and fail to reveal capacitors with cracks. Index Terms: Ceramic capacitor, insulation resistance, dielectric absorption, cracking.

Use of new ceramic linings in coal preparation plants

Energy Technology Data Exchange (ETDEWEB)

Fedorchenko, V.E.; Rudenko, V.A.; Bondarev, A.Ya.

1984-01-01

This article evaluates several materials used as liners in coal preparation equipment. The evaluations concentrate on liners used under conditions of intensive temperature fluctuations, e.g. liners of coal chutes for coal transport from coal dryers. Two aspects of wear are analyzed: abrasion by friction and effects of temperature fluctuations. Abrasive wear is tested using magnetite suspension with a density of 400 g/l. Tests show that abrasive wear of liners on an alumina basis is 3 times lower than abrasive wear of high quality steel, from 13 to 24 times lower than that of iron and from 6 to 8 times lower than that of steels used in coal preparation plants. Effects of temperature fluctuations from 20 to 840 C on abrasive wear of liners of steels, iron, slag glass ceramics, mullite-corundum material and corundum is shown in a table. The test show that mullite-corundum material on the basis of alumina is characterized by a high resistance to abrasive wear after 30 cycles of temperature increase from 20 to 840 C and decrease to 20 C. Using mullite-corundum as liners of equipment and installations operating under conditions of temperature fluctuations is recommended.

Wear Resistance of 3D Printing Resin Material Opposing Zirconia and Metal Antagonists

Directory of Open Access Journals (Sweden)

Ji-Man Park

2018-06-01

Full Text Available 3D printing offers many advantages in dental prosthesis manufacturing. This study evaluated the wear resistance of 3D printing resin material compared with milling and conventional resin materials. Sixty substrate specimens were prepared with three types of resin materials: 3D printed resin, milled resin, and self-cured resin. The 3D printed specimens were printed at a build angle of 0° and 100 μm layer thickness by digital light processing 3D printing. Two kinds of abraders were made of zirconia and CoCr alloy. The specimens were loaded at 5 kg for 30,000 chewing cycles with vertical and horizontal movements under thermocycling condition. The 3D printed resin did not show significant difference in the maximal depth loss or the volume loss of wear compared to the milled and the self-cured resins. No significant difference was revealed depending on the abraders in the maximal depth loss or the volume loss of wear. In SEM views, the 3D printed resin showed cracks and separation of inter-layer bonds when opposing the metal abrader. The results suggest that the 3D printing using resin materials provides adequate wear resistance for dental use.

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

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Kaiming Wang

2017-12-01

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

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.

Are PEEK-on-Ceramic Bearings an Option for Total Disc Arthroplasty? An In Vitro Tribology Study.

Science.gov (United States)

Siskey, Ryan; Ciccarelli, Lauren; Lui, Melissa K C; Kurtz, Steven M

2016-11-01

Most contemporary total disc replacements (TDRs) use conventional orthopaedic bearing couples such as ultrahigh-molecular-weight polyethylene (polyethylene) and cobalt-chromium (CoCr). Cervical total disc replacements incorporating polyetheretherketone (PEEK) bearings (specifically PEEK-on-PEEK bearings) have been previously investigated, but little is known about PEEK-on-ceramic bearings for TDR. (1) What is the tribologic behavior of a PEEK-on-ceramic bearing for cervical TDR under idealized, clean wear test conditions? (2) How does the PEEK-on-ceramic design perform under impingement conditions? (3) How is the PEEK-on-ceramic bearing affected by abrasive wear? (4) Is the particle morphology from PEEK-on-ceramic bearings for TDRs affected by adverse wear scenarios? PEEK-on-ceramic cervical TDR bearings were subjected to a 10 million cycle ideal wear test based on ASTM F2423 and ISO 181912-1 using a six-station spine wear simulator (MTS, Eden Prairie, MN, USA) with 5 g/L bovine serum concentration at 23° ± 2° C (ambient temperature). Validated 1 million cycle impingement and 5 million cycle abrasive tests were conducted on the PEEK-on-ceramic bearings based, in part, on retrieval analysis of a comparable bearing design as well as finite element analyses. The ceramic-on-PEEK couple was characterized for damage modes, mass and volume loss, and penetration and the lubricant was subjected to particle analysis. The resulting mass wear rate, volumetric wear rate, based on material density, and particle analysis were compared with clinically available cervical disc bearing couples. The three modes of wear (idealized, impingement, and abrasive) resulted in mean mass wear rates of 0.9 ± 0.2 mg/MC, 1.9 ± 0.5 mg/MC, and 2.8 ± 0.6 mg/MC, respectively. The mass wear rates were converted to volumetric wear rates using density and found to be 0.7 ± 0.1 mm 3 /MC, 1.5 ± 0.4 mm 3 /MC, and 2.1 ± 0.5 mm 3 /MC, respectively. During each test, the PEEK

Microstructure and Wear Resistance of TIG Remelted NiCrBSi Thick Coatings

Directory of Open Access Journals (Sweden)

Guo-lu Li

2018-01-01

Full Text Available The self-fluxing NiCrBSi coatings with 800 μm thickness were prepared on the surface of AISI1045 steel substrate by plasma spraying. And the remelted coating was obtained using by the tungsten inert gas (TIG arc process. The microstructure, surface roughness, hardness, phase composition, and wear resistance of the sprayed coating and remelted coating were systematically investigated. The results demonstrate that TIG remelted treatment can significantly eliminate the microscopic defects in thick coating and improve its density. The surface roughness (Ra of the remelted coating is only 18.9% of the sprayed coating. The hardness of the remelted coating is 26.8% higher than that of the sprayed coating. The main phases in the sprayed coating are changed from γ-Ni, Cr7C3, and Cr2B to γ-Ni, Cr23C6, CrB, Ni3B, and Fe3C. The wear mass loss of the remelted coating is only 17.1% of the sprayed coating. Therefore, a Ni-based thick coating with good wear resistance can be obtained by plasma spraying and remelted technique.

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.

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

Directory of Open Access Journals (Sweden)

Katya Gotlib-Vainshtein

2014-07-01

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

Wear Resistant Thermal Sprayed Composite Coatings Based on Iron Self-Fluxing Alloy and Recycled Cermet Powders

Directory of Open Access Journals (Sweden)

Heikki SARJAS

2012-03-01

Full Text Available Thermal spray and WC-Co based coatings are widely used in areas subjected to abrasive wear. Commercial  cermet thermal spray powders for HVOF are relatively expensive. Therefore applying these powders in cost-sensitive areas like mining and agriculture are hindered. Nowadays, the use of cheap iron based self-fluxing alloy powders for thermal spray is limited. The aim of this research was to study properties of composite powders based on self-fluxing alloys and recycled cermets and to examine the properties of thermally sprayed (HVOF coatings from composite powders based on iron self-fluxing alloy and recycled cermet powders (Cr3C2-Ni and WC-Co. To estimate the properties of  recycled cermet powders, the sieving analysis, laser granulometry and morphology were conducted. For deposition of coatings High Velocity Oxy-Fuel spray was used. The structure and composition of powders and coatings were estimated by SEM and XRD methods. Abrasive wear performance of coatings was determined and compared with wear resistance of coatings from commercial powders. The wear resistance of thermal sprayed coatings from self-fluxing alloy and recycled cermet powders at abrasion is comparable with wear resistance of coatings from commercial expensive spray powders and may be an alternative in tribological applications in cost-sensitive areas.DOI: http://dx.doi.org/10.5755/j01.ms.18.1.1338

Preparation, microstructural evolution and properties of Ni–Zr intermetallic/Zr–Si ceramic reinforced composite coatings on zirconium alloy by laser cladding

Energy Technology Data Exchange (ETDEWEB)

Liu, Kun; Li, Yajiang, E-mail: yajli@sdu.edu.cn; Wang, Juan; Ma, Qunshuang; Li, Jishuai; Li, Xinyue

2015-10-25

NiZr{sub 2}–ZrSi–Zr{sub 5}(Si{sub x}Ni{sub 1−x}){sub 4}-ZrC intermetallic/ceramic reinforced composite coatings were in situ synthesized by laser cladding the pre-placed Ni–Cr–B–Si powder on zirconium substrate. Microstructure and phase constituents were investigated by X-ray diffraction (XRD), optical microscope (OM), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). Microhardness tester and block-on-ring wear tester were employed to measure the hardness distribution and wear resistance of the intermetallic/ceramic reinforced composite coating. Results indicated that the multiphase of reinforcements includes Ni–Zr intermetallic compounds (e.g., NiZr and NiZr{sub 2}) and Zr–Si(C) ceramic phases (e.g., ZiSi, Zr{sub 5}Si{sub 4} and ZrC). Ni–Si clusters transforming to Zr–Si–Ni clusters at high temperature facilitated the forming of Zr{sub 5}(Si{sub x}Ni{sub 1−x}){sub 4} and during the growth of Zr{sub 5}(Si{sub x}Ni{sub 1−x}){sub 4}, the consumption of Zr atoms at the lateral interface of liquid/Zr{sub 5}(Si{sub x}Ni{sub 1−x}){sub 4} resulted into developing Zr-poor zone near Zr{sub 5}(Si{sub x}Ni{sub 1−x}){sub 4}. The microhardness and wear resistance of the coating were significantly improved by various reinforced phases in comparison to zirconium substrate. - Highlights: • NiZr{sub 2}–ZrSi–Zr{sub 5}(Si{sub x}Ni{sub 1−x}){sub 4}-ZrC compostie coating was in-situ synthesized. • Ni–Si clusters transforming resulted into developing Zr-poor zone near Zr{sub 5}(Si{sub x}Ni{sub 1−x}){sub 4}. • Reinforced phases significantly improve wear resistance of the coating.

Hydrothermal development and characterization of the wear-resistant boron carbide from Pandanus: a natural carbon precursor

Science.gov (United States)

Saritha Devi, H. V.; Swapna, M. S.; Ambadas, G.; Sankararaman, S.

2018-04-01

Boron carbide (B4C) is a prominent semiconducting material that finds applications in the field of science and technology. The excellent physical, thermal and electronic properties make it suitable as ceramic armor, wear-resistant, lens polisher and neutron absorber in the nuclear industry. The existing methods of synthesis of boron carbide involve the use of toxic chemicals that adversely affect the environment. In the present work, we report for the first time the use of the hydrothermal method, for converting the cellulose from Pandanus leaves as the carbon precursor for the synthesis of B4C. The carbon precursor is changed into porous functionalized carbon by treating with sodium borohydride (NaBH4), followed by treating with boric acid to obtain B4C. The samples are characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared, Raman, photoluminescent and Ultraviolet-Visible absorption spectroscopy. The formation of B4C from natural carbon source— Pandanus presents an eco-friendly, economic and non-toxic approach for the synthesis of refractory carbides.

Effect of SiC Content on Microstructure and Wear Resistance of Laser Cladding SiC/Ni60A Composite Coating

Directory of Open Access Journals (Sweden)

ZHAO Long-zhi

2017-03-01

Full Text Available The SiC reinforced Ni60A alloy laser cladding coating on the 45 steel substrate was fabricated with the LDM2500-60 semiconductor laser equipment. The effect of SiC content on microstructure, dilution rate, wear resistance, friction coefficient and microhardness was investigated systematically.The results show that with the increase of SiC content, the microstructure of upper coating is refined obviously, the dilution rate, wear resistance, friction coefficient and microhardness increase firstly and then decrease;when the mass fraction of SiC is 20%, the wear resistance of the cladding coating is the best one, in which the wear loss of coating is only 0.0012g and is 1/36.3 of the matrix;the minimum friction coefficient is 0.464, the friction process is the most stable;the highest microhardness of the cladding coating is 1039.9HV0.2, which is 3.5 times of the substrate;but when the mass fraction of SiC is 25%, the microhardness and wear resistance of coating decrease.

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.

Vacuum tight sodium resistant compound between ThO2 ceramic and metal

International Nuclear Information System (INIS)

Reetz, T.

A method for evaluating the mechanical tensions for metal/ ceramic joinings was applied to the selection of metal components for a highly vacuum tight, sodium-resistant metal/ThO 2 ceramic solder joining. The metal component selected was the iron--nickel alloy Dilasil which is joined to the ceramic using a nickel-based solder. The wetting of the cearamic could be carried out using the titanium hydride technique or after the formation of a W-cerium layer on the surface of this ceramic. (U.S.)

Wear resistance of layers hard faced by the high-alloyed filler metal

OpenAIRE

Dušan Arsić; Vukić Lazić; Ruzica R. Nikolic; Milan Mutavdžić; Srbislav Aleksandrović; Milan Djordjević

2016-01-01

The objective of this work was to determine the wear resistance of layers hard faced by the high-alloyed filler metal, with or without the austenite inter-layer, on parts that operate at different sliding speeds in conditions without lubrication. The samples were hard faced with the filler metal E 10-UM-60-C with high content of C, Cr and W. Used filler metal belongs into group of alloys aimed for reparatory hard facing of parts damaged by abrasive and erosive wear and it is characterized by ...

Effects of Synchronous Rolling on Microstructure, Hardness, and Wear Resistance of Laser Multilayer Cladding

Science.gov (United States)

Zhao, W.; Zha, G. C.; Xi, M. Z.; Gao, S. Y.

2018-03-01

A synchronous rolling method was proposed to assist laser multilayer cladding, and the effects of this method on microstructure, microhardness, and wear resistance were studied. Results show that the microstructure and mechanical properties of the traditional cladding layer exhibit periodic inhomogeneity. Synchronous rolling breaks the columnar dendrite crystals to improve the uniformity of the organization, and the residual plastic energy promotes the precipitation of strengthening phases, as CrB, M7C3, etc. The hardness and wear resistance of the extruded cladding layer increase significantly because of the grain refinement, formation of dislocations, and dispersion strengthening. These positive significances of synchronous rolling provide a new direction for laser cladding technology.

ASSESSMENT OF CERAMIC TILE FROST RESISTANCE BY MEANS OF THE FREQUENCY INSPECTION METHOD

Directory of Open Access Journals (Sweden)

MICHAL MATYSÍK

2011-06-01

Full Text Available The paper presents some results of our experimental analysis of ceramic cladding element frost resistance, particular attention being paid to the application of the frequency inspection method. Three different sets of ceramic tiles of the Ia class to EN 14 411 B standard made by various manufacturers have been analyzed. The ceramic tiles under investigation have been subjected to freeze-thaw-cycle-based degradation in compliance with the relevant ČSN EN ISO 10545-12 standard. Furthermore, accelerated degradation procedure has been applied to selected test specimens, consisting in reducing the temperature of water soaked ceramic tiles in the course of the degradation cycles down –70°C. To verify the correctness of the frequency inspection results, additional physical properties of the ceramic tiles under test have been measured, such as, the ceramic tile strength limit, modulus of elasticity and modulus of deformability, resulting from the flexural tensile strength tests, integrity defect and surface micro-geometry tracking. It has been proved that the acoustic method of frequency inspection is a sensitive indicator of the structure condition and can be applied to the ceramic cladding element frost resistance and service life prediction assessment.

Effect of vanadium of mechanical behavior, machinability and wear resistance of aluminium grain refined by Ti+B

International Nuclear Information System (INIS)

Zaid, A.I.O.; Hamid, A.A.A.

1999-01-01

It is well established that aluminum and its alloys are industrially grain refined by adding either Ti or Ti-B to improve their mechanical behavior and surface finish. In a previous paper, it was found that the grain refining efficiency of aluminum master alloys containing Ti or Ti+B was enhanced by addition of small amounts of other elements including vanadium. V. Therefore, it is anticipated that such an element will improve mechanical behavior, machinability and wear resistance of aluminum and its alloys. In this paper, the effect of vanadium addition, up to 0.3% on mechanical behavior is investigated. Machinability was assessed under different cutting conditions: speed, feed and depth of cut and finally the wear resistance was determined at different loads and speeds. The results indicated that improvement in hardness and mechanical strength were achieved by the addition of V that addition of more than 0.2%V resulted in little or no improvement. Similarly, addition of V resulted in improvement of surface quality under the different cutting conditions of speed, feed and depth of cut, and resistance to wear. However addition of more than 0.2% V resulted in increase of wear rate and change of wear mechanisms. (author)

Development of a thin film vitreous bond based composite ceramic coating for corrosion and abrasion services

International Nuclear Information System (INIS)

Franke, B.

2003-01-01

IPC has been involved with the Alberta Research Council in developing a vitreous bond (VB) - based composite ceramic fluoropolymer coating technology. Compared to the present state of the art which is based on a hard discontinuous phase (ceramic particles) suspended in a soft continuous matrix (fluoropolymer mix) the novelty of our approach consists of designing a composite system in which both the ceramic and the fluoropolymer phases are continuous. The ceramic matrix will provide the strength and the erosion resistance for the fluoropolymer matrix even at high temperatures. The ceramic formulation employed is not affected by temperatures up to 500 o F while the fluoropolymer matrix provides a corrosion protection seal for the ceramic matrix. The inherent flexibility of the polymer matrix will protect against brittle fractures that may develop by handling or impact. Therefore the composite coating is able to withstand the deformation of the substrate without chipping or disbanding. The fluoropolymer matrix also provides dry lubrication properties further enhancing the erosion resistance of the ceramic phase. The thickness of the coating is very thin, in the 25 to 100 micron range. In summary, the coating technology is able to provide the following features: Corrosion protection levels similar to those of fluoropolymer coatings; Erosion resistance similar to that of ceramic coatings; Price comparable to that of polymer coatings; Exceptional wear resistance properties; and Capability for coating complicated shapes internally or externally or both. This paper will discuss the theory and development of this new technology and the resultant coating and potential properties. (author)

Confocal examination of subsurface cracking in ceramic materials.

Science.gov (United States)

Etman, Maged K

2009-10-01

The original ceramic surface finish and its microstructure may have an effect on crack propagation. The purpose of this study was to investigate the relation between crack propagation and ceramic microstructure following cyclic fatigue loading, and to qualitatively evaluate and quantitatively measure the surface and subsurface crack depths of three types of ceramic restorations with different microstructures using a Confocal Laser Scanning Microscope (CLSM) and Scanning Electron Microscope (SEM). Twenty (8 x 4 x 2 mm(3)) blocks of AllCeram (AC), experimental ceramic (EC, IPS e.max Press), and Sensation SL (SSL) were prepared, ten glazed and ten polished of each material. Sixty antagonist enamel specimens were made from the labial surfaces of permanent incisors. The ceramic abraders were attached to a wear machine, so that each enamel specimen presented at 45 degrees to the vertical movement of the abraders, and immersed in artificial saliva. Wear was induced for 80K cycles at 60 cycles/min with a load of 40 N and 2-mm horizontal deflection. The specimens were examined for cracks at baseline, 5K, 10K, 20K, 40K, and 80K cycles. Twenty- to 30-microm deep subsurface cracking appeared in SSL, with 8 to 10 microm in AC, and 7 microm close to the margin of the wear facets in glazed EC after 5K cycles. The EC showed no cracks with increasing wear cycles. Seventy-microm deep subsurface cracks were detected in SSL and 45 microm in AC after 80K cycles. Statistically, there was significant difference among the three materials (p 0.05) in crack depth within the same ceramic material with different surface finishes. The ceramic materials with different microstructures showed different patterns of subsurface cracking.

Ceramic Technology Project semiannual progress report for October 1991--March 1992

Energy Technology Data Exchange (ETDEWEB)

1992-09-01

Objective is to develop the industrial technology base required for reliable ceramics for application in advanced automotive heat engines. Focus is on structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines. The work is organized into the following elements: materials and processing (monolithics [SiC, SiN], ceramic composites, thermal and wear coatings, joining), materials design methodology, data base and life prediction (structural qualification, time-dependent behavior, environmental effects, fracture mechanics, NDE), and technology transfer. Individual abstracts were prepared for the individual contributions.

Hard metal - a wear resistant material. Hartmetall - ein verschleissbestaendiger Werkstoff

Energy Technology Data Exchange (ETDEWEB)

Kolaska, J.; Dreyer, K. (Krupp Widia GmbH, Essen (Germany, F.R.))

1989-01-01

The article provides a survey of the various types of alloys of presently used carbides, their production processes and properties. Cermets (alloys with a high content of titanium carbide) are in the foreground here. With an eye on the future, advancements of further improved carbide materials are described, which feature at the same time a high resistance to wear and tenacity. (orig.).

Fatigue resistance and microleakage of CAD/CAM ceramic and composite molar crowns.

Science.gov (United States)

Kassem, Amr S; Atta, Osama; El-Mowafy, Omar

2012-01-01

The aim of this study was to determine effect of compressive cyclic loading on fatigue resistance and microleakage of monolithic CAD/CAM molar ceramic and composite crowns. Thirty-two extracted molars were prepared to receive CEREC crowns according to manufacturer's guidelines using a special paralleling device (Parallel-A-Prep). Sixteen feldspathic ceramic crowns (VITABLOCS Mark II) (VMII) and 16 resin-composite crowns (Paradigm-MZ100 blocks) (PMZ) were milled using a CEREC-3D machine. Eight crowns of each group were cemented to their respective teeth using self-etching resin cement (Panavia-F-2.0) (PAN), and eight were cemented using self-adhesive resin cement (RelyX-Unicem-Clicker) (RXU). Following storage for 1 week in water, specimens were subjected to uniaxial compressive cyclic loading in an Instron testing machine at 12 Hz for 1,000,000 cycles. Load was applied at the central fossa, and the cycle range was 60-600 N. Specimens were then subjected to microleakage testing. Data were statistically analyzed using factorial ANOVA and Post Hoc (Tukey HSD) tests. All composite crowns survived compressive cyclic loading without fracture, while three ceramic crowns from the subgroup cemented with RXU developed surface cracks at the center of occlusal surfaces, extending laterally. Microleakage scores of ceramic crowns cemented with PAN were significantly lower than those of the other three subgroups (p < 0.05). After 1,000,000 cycles of compressive cyclic loading, PMZ composite molar crowns were more fatigue-resistant than VMII ceramic crowns. Cement type had a significant effect on fatigue resistance of the ceramic crowns but not the composite ones. Microleakage scores of ceramic crowns cemented with PAN were significantly lower than those of the other subgroups (p < 0.05). © 2011 by The American College of Prosthodontists.

Microstructure and Wear Resistance of Composite Coating by Laser Cladding Al/TiN on the Ti-6Al-4V Substrate

Science.gov (United States)

Zhang, H. X.; Yu, H. J.; Chen, C. Z.

2015-05-01

The composite coatings were fabricated by laser cladding Al/TiN pre-placed powders on Ti-6Al-4V substrate for enhancing wear resistance and hardness of the substrate. The composite coatings were analyzed by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The sliding wear tests were performed by MM200 wear test machine. The hardness of the coatings was tested by HV-1000 hardness tester. After laser cladding, it was found that there was a good metallurgical bond between the coating and the substrate. The composite coatings were mainly composed of the matrix of β-Ti (Al) and the reinforcements of titanium nitride (TiN), Ti3Al, TiAl and Al3Ti. The hardness and wear resistance of the coatings on four samples were greatly improved, among which sample 4 exhibited the highest hardness and best wear resistance. The hardness of the coating on sample 4 was approximately 2.5 times of the Ti-6Al-4V substrate. And the wear resistance of sample 4 was four times of the substrate.

FEM-DEM coupling simulations of the tool wear characteristics in prestressed machining superalloy

Directory of Open Access Journals (Sweden)

Ruitao Peng

2016-01-01

Full Text Available Due to the complicated contact loading at the tool-chip interface, ceramic tool wear in prestressed machining superalloy is rare difficult to evaluate only by experimental approaches. This study aims to develop a methodology to predict the tool wear evolution by using combined FEM and DEM numerical simulations. Firstly, a finite element model for prestressed cutting is established, subsequently a discrete element model to describe the tool-chip behaviour is established based on the obtained boundary conditions by FEM simulations, finally, simulated results are experimentally validated. The predicted tool wear results show nice agreement with experiments, the simulation indicates that, within a certain range, higher cutting speed effectively results in slighter wear of Sialon ceramic tools, and deeper depth of cut leads to more serious tool wear.

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.

A fractographic study of clinically retrieved zirconia–ceramic and metal–ceramic fixed dental prostheses

Science.gov (United States)

Pang, Zhen; Chughtai, Asima; Sailer, Irena; Zhang, Yu

2015-01-01

Objectives A recent 3-year randomized controlled trial (RCT) of tooth supported three- to five-unit zirconia–ceramic and metal–ceramic posterior fixed dental prostheses (FDPs) revealed that veneer chipping and fracture in zirconia–ceramic systems occurred more frequently than those in metal–ceramic systems [1]. This study seeks to elucidate the underlying mechanisms responsible for the fracture phenomena observed in this RCT using a descriptive fractographic analysis. Methods Vinyl-polysiloxane impressions of 12 zirconia–ceramic and 6 metal–ceramic FDPs with veneer fractures were taken from the patients at the end of a mean observation of 40.3 ± 2.8 months. Epoxy replicas were produced from these impressions [1]. All replicas were gold coated, and inspected under the optical microscope and scanning electron microscope (SEM) for descriptive fractography. Results Among the 12 zirconia–ceramic FDPs, 2 had small chippings, 9 had large chippings, and 1 exhibited delamination. Out of 6 metal–ceramic FDPs, 5 had small chippings and 1 had large chipping. Descriptive fractographic analysis based on SEM observations revealed that fracture initiated from the wear facet at the occlusal surface in all cases, irrespective of the type of restoration. Significance Zirconia–ceramic and metal–ceramic FDPs all fractured from microcracks that emanated from occlusal wear facets. The relatively low fracture toughness and high residual tensile stress in porcelain veneer of zirconia restorations may contribute to the higher chipping rate and larger chip size in zirconia–ceramic FDPs relative to their metal–ceramic counterparts. The low veneer/core interfacial fracture energy of porcelain-veneered zirconia may result in the occurrence of delamination in zirconia–ceramic FDPs. PMID:26233469

Improvement of the wear resistance of electroplated Au-Ni coatings by Zr ion bombardment of Ni-B sublayer

International Nuclear Information System (INIS)

Lyazgin, Alexander; Shugurov, Artur; Sergeev, Viktor; Neufeld, Vasily; Panin, Alexey; Shesterikov, Evgeny

2015-01-01

The effect of bombardment of the Ni-B sublayer by Zr ion beams on the surface morphology and tribomechanical properties of Au-Ni coatings was investigated. It was found that the treatment has no significant effect on the surface roughness and grain size of the Au-Ni coatings, while it provides essential reducing of their friction coefficient and improvement of wear resistance. It is shown that increased wear resistance of these coatings was caused by their strain hardening resulted from localization of plastic strain. The optimal Zr fluence were determined that provide the maximum reduction of linear wear of the coatings

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.

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.

Microtensile Bond Strength Compared Between CAD/CAM Feldspathic and Resin Nano Ceramics

Science.gov (United States)

2015-07-27

tend to be brittle and prone to fracture, while flexible materials are less resistant to wear. Teeth have evolved with hard enamel that is brittle...ceramic fractures: the Hertzian cone crack (24), often resulting from surface damage on the occlusal surface that extends deeper into the restoration...and radial cracks that form at the cementation zone (25). Fracture mechanics and fractography are both important fields utilized in assessing the

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.

Radiation-hard ceramic Resistive Plate Chambers for forward TOF and T0 systems

Energy Technology Data Exchange (ETDEWEB)

Akindinov, A., E-mail: Alexander.Akindinov@cern.ch [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Dreyer, J.; Fan, X.; Kämpfer, B. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Kiselev, S. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Kotte, R.; Garcia, A. Laso [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Malkevich, D. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Naumann, L. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Nedosekin, A.; Plotnikov, V. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Stach, D. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Sultanov, R.; Voloshin, K. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation)

2017-02-11

Resistive Plate Chambers with ceramic electrodes are the main candidates for a use in precise multi-channel timing systems operating in high-radiation conditions. We report the latest R&D results on these detectors aimed to meet the requirements of the forward T0 counter at the CBM experiment. RPC design, gas mixture, limits on the bulk resistivity of ceramic electrodes, efficiency, time resolution, counting rate capabilities and ageing test results are presented.

Polishing of silicon based advanced ceramics

Science.gov (United States)

Klocke, Fritz; Dambon, Olaf; Zunke, Richard; Waechter, D.

2009-05-01

Silicon based advanced ceramics show advantages in comparison to other materials due to their extreme hardness, wear and creep resistance, low density and low coefficient of thermal expansion. As a matter of course, machining requires high efforts. In order to reach demanded low roughness for optical or tribological applications a defect free surface is indispensable. In this paper, polishing of silicon nitride and silicon carbide is investigated. The objective is to elaborate scientific understanding of the process interactions. Based on this knowledge, the optimization of removal rate, surface quality and form accuracy can be realized. For this purpose, fundamental investigations of polishing silicon based ceramics are undertaken and evaluated. Former scientific publications discuss removal mechanisms and wear behavior, but the scientific insight is mainly based on investigations in grinding and lapping. The removal mechanisms in polishing are not fully understood due to complexity of interactions. The role of, e.g., process parameters, slurry and abrasives, and their influence on the output parameters is still uncertain. Extensive technological investigations demonstrate the influence of the polishing system and the machining parameters on the stability and the reproducibility. It is shown that the interactions between the advanced ceramics and the polishing systems is of great relevance. Depending on the kind of slurry and polishing agent the material removal mechanisms differ. The observed effects can be explained by dominating mechanical or chemo-mechanical removal mechanisms. Therefore, hypotheses to state adequate explanations are presented and validated by advanced metrology devices, such as SEM, AFM and TEM.

New Effective Material Couple--Oxide Ceramic and Carbon Nanotube-- Developed for Aerospace Microsystem and Micromachine Technologies

Science.gov (United States)

Miyoshi, Kazuhisa; VanderWal, Randall L.; Tomasek, Aaron J.; Sayir, Ali; Farmer, Serene C.

2004-01-01

The prime driving force for using microsystem and micromachine technologies in transport vehicles, such as spacecraft, aircraft, and automobiles, is to reduce the weight, power consumption, and volume of components and systems to lower costs and increase affordability and reliability. However, a number of specific issues need to be addressed with respect to using microsystems and micromachines in aerospace applications--such as the lack of understanding of material characteristics; methods for producing and testing the materials in small batches; the limited proven durability and lifetime of current microcomponents, packaging, and interconnections; a cultural change with respect to system designs; and the use of embedded software, which will require new product assurance guidelines. In regards to material characteristics, there are significant adhesion, friction, and wear issues in using microdevices. Because these issues are directly related to surface phenomena, they cannot be scaled down linearly and they become increasingly important as the devices become smaller. When microsystems have contacting surfaces in relative motion, the adhesion and friction affect performance, energy consumption, wear damage, maintenance, lifetime and catastrophic failure, and reliability. Ceramics, for the most part, do not have inherently good friction and wear properties. For example, coefficients of friction in excess of 0.7 have been reported for ceramics and ceramic composite materials. Under Alternate Fuels Foundation Technologies funding, two-phase oxide ceramics developed for superior high-temperature wear resistance in NASA's High Operating Temperature Propulsion Components (HOTPC) project and new two-layered carbon nanotube (CNT) coatings (CNT topcoat/iron bondcoat/quartz substrate) developed in NASA's Revolutionary Aeropropulsion Concepts (RAC) project have been chosen as a materials couple for aerospace applications, including micromachines, in the nanotechnology

Wear resistance of thick diamond like carbon coatings against polymeric materials used in single screw plasticizing technology

Science.gov (United States)

Zitzenbacher, G.; Liu, K.; Forsich, C.; Heim, D.

2015-05-01

Wear on the screw and barrel surface accompany polymer single screw plasticizing technology from the beginning. In general, wear on screws can be reduced by using nitrided steel surfaces, fused armour alloys on the screw flights and coatings. However, DLC-coatings (Diamond Like Carbon) comprise a number of interesting properties such as a high hardness, a low coefficient of friction and an excellent corrosion resistance due to their amorphous structure. The wear resistance of about 50 µm thick DLC-coatings against polyamide 6.6, polybutylene terephthalate and polypropylene is investigated in this paper. The tribology in the solids conveying zone of a single screw extruder until the beginning of melting is evaluated using a pin on disc tribometer and a so called screw tribometer. The polymeric pins are pressed against coated metal samples using the pin on disc tribometer and the tests are carried out at a defined normal force and sliding velocity. The screw tribometer is used to perform tribological experiments between polymer pellets and rotating coated metal shafts simulating the extruder screw. Long term experiments were performed to evaluate the wear resistance of the DLC-coating. A reduction of the coefficient of friction can be observed after a frictional distance of about 20 kilometers using glass fibre reinforced polymeric materials. This reduction is independent on the polymer and accompanied by a black layer on the wear surface of the polymeric pins. The DLC-coated metal samples show an up to 16 µm deep wear track after the 100 kilometer test period against the glass fiber filled materials only.

Erosion resistance and adhesion of composite metal/ceramic coatings produced by plasma spraying

OpenAIRE

Ramm , D.; Hutchings , I.; Clyne , T.

1993-01-01

Ceramic coatings can exhibit greater erosion resistance than most metallic coatings. Such coatings are conveniently produced by thermal spraying. Unfortunately, thermally sprayed ceramic coatings often exhibit poor adhesion, partly as a consequence of the development of residual stresses during spraying and subsequent cooling. Composite coatings have been studied using aluminium/alumina deposits on steel substrates. The incorporation of ceramics within a ductile matrix has potential for sharp...

Tribology of ceramics: Report of the Committee on Tribology of Ceramics

Science.gov (United States)

1988-01-01

The current state of knowledge of ceramic surface structures, composition, and reactivity is reviewed. The tribological requirements of advanced mechanical systems now being deployed (in particular, heat engines) exceed the capabilities of traditional metallic-based materials because of the high temperatures encountered. Advanced ceramic materials for such applications are receiving intense scrutiny, but there is a lack of understanding of the properties and behavior of ceramic surfaces and the influence of processing on the properties of ceramics is described. The adequacy of models, ranging form atomic to macro, to describe and to predict ceramic friction and wear are discussed, as well as what is known about lubrication at elevated temperatures. From this analysis, recommendations are made for coordination, research, and development that will lead to better performance of ceramic materials in tribological systems.

Ceramic tantalum oxide thin film coating to enhance the corrosion and wear characteristics of Ti−6Al−4V alloy

Energy Technology Data Exchange (ETDEWEB)

Rahmati, B., E-mail: r.bijan@yahoo.com [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Sarhan, Ahmed A.D., E-mail: ah_sarhan@um.edu.my [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Basirun, W. Jeffrey [Department of Chemistry, University of Malaya, 50603 Kuala Lumpur (Malaysia); Abas, W.A.B.W. [Department of Biomedical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2016-08-15

In this research, an attempt is made to study the corrosion and wear behavior of TaO{sub 2} thin film coating deposited onto Ti−6Al−4V alloy with the highest adhesion (was achieved in the author's previous experiments using Taguchi statistical method) which leads to increase corrosion resistance, decrease debris generation and improve durability. Accordingly, pure tantalum (Ta) was deposited onto Ti−6Al−4V substrate surface as intermetallic layer then to form a TaO{sub 2} thin film, Ta was deposited onto the sample surface in the presence of oxygen by using physical vapor deposition magnetron sputtering (PVDMS). Corrosion testing was carried out in fetal bovine serum (FBS). The corrosion test in FBS medium confirmed that the corrosion resistance of the TaO{sub 2} – coated Ti−6Al−4V alloys was significantly higher than the uncoated Ti−6Al−4V substrate due to the decrease in corrosion current density (I{sub corr}) for the coated substrate with high thin-film adhesion. Wear testing was carried out on uncoated and coated Ti−6Al−4V substrates in the presence of FBS medium under 15 N load (natural walking load) at 1.09 m/s (simulated medium walking speed). The tests revealed that the specific wear ratio of TaO{sub 2} coating was significantly lower than the uncoated substrate wear ratio. The average friction coefficients obtained were 0.183 and 0.152 for uncoated substrate and TaO{sub 2} thin film coating, respectively. So, due to the noticeable corrosion and wear resistance characteristics of the TaO{sub 2} coating, it is suggested for hip joint implant. - Highlights: • The TaO{sub 2} coating has been created onto the Ti−6Al−4V surface by using PVDMS method. • The TaO{sub 2} coating has been formed on the Ti−6Al−4V sample at the highest adhesion. • The corrosion resistance of the coated Ti−6Al−4V substrate has been improved. • The wear resistance of the coated Ti−6Al−4V substrate has been increased. • The durability

Obtainment, machining and wear of metal matrix composites processed by powder metallurgy

International Nuclear Information System (INIS)

Jesus, Edilson Rosa Barbosa de.

1998-01-01

The aim of this investigation was the obtainment of metal matrix composites (MMC) by the route of powder metallurgy, and the valuation of these materials with relation to their machining and wear characteristics. Firstly, were obtained pure commercial aluminium matrix composites materials, with 5, 10 and 15% volumetric fraction of silicon carbide particles. Was also obtained a material without reinforcement particles in order to verify by comparison, the influence of addition of reinforcement particles. The obtained materials were characterized physics (hydrostatic density), mechanics (hardness and tensile tests) and microstructurally (optical microscopy and scanning electron microscopy). The results showed a homogeneous distribution of reinforcement particles in the composite, and improvement in the mechanical properties, mainly tensile strength (UTS) in comparison to the unreinforced material. After, tests were made to verify the materials behavior during machining and to check the performance of several tool materials (cemented carbide, ceramics and polycrystalline diamond). In these tests, values of the cutting force were measured by instrumented tool-holders. Phenomena such as tool wear, built-up edge formation and mechanism of chip formation were also observed and evaluated. The results from the cemented carbide tool tests, were utilised for the machinability index determination of each material. These results were applied to the Taylor equation and the equation constants for each material and test conditions were determined. The results showed that the inclusion of silicon carbide particles made extremely difficult the machining of the composites, and only with diamond tool, satisfactory results were obtained. At last, wear tests were performed to verify the influence of the reinforcement particles in the characteristics of wear resistance of the materials. The results obtained were utilized in the wear coefficient determination for each material. The

A method for increase abrasive wear resistance parts by obtaining on methods casting on gasifying models

Science.gov (United States)

Sedukhin, V. V.; Anikeev, A. N.; Chumanov, I. V.

2017-11-01

Method optimizes hardening working layer parts’, working in high-abrasive conditions looks in this work: bland refractory particles WC and TiC in respect of 70/30 wt. % prepared by beforehand is applied on polystyrene model in casting’ mould. After metal poured in mould, withstand for crystallization, and then a study is carried out. Study macro- and microstructure received samples allows to say that thickness and structure received hardened layer depends on duration interactions blend harder carbides and liquid metal. Different character interactions various dispersed particles and matrix metal observed under the same conditions. Tests abrasive wear resistance received materials of method calculating residual masses was conducted in laboratory’ conditions. Results research wear resistance showed about that method obtaining harder coating of blend carbide tungsten and carbide titanium by means of drawing on surface foam polystyrene model before moulding, allows receive details with surface has wear resistance in 2.5 times higher, than details of analogy steel uncoated. Wherein energy costs necessary for transformation units mass’ substances in powder at obtained harder layer in 2.06 times higher, than materials uncoated.

Enhanced wear resistance of production tools and steel samples by implantation of nitrogen and carbon ions

International Nuclear Information System (INIS)

Mikkelsen, N.J.; Straede, C.A.

1992-01-01

In recent years ion implantation has become a feasible technique for obtaining improved wear resistance of production tools. However, basic knowledge of how and in which cases ion implantation is working at its best is still needed. The present paper discusses structural and tribological investigations of carbon and nitrogen implanted steels. The nitrogen data were obtained mainly from field tests and the investigation of carbon implantations took place mainly in the laboratory. A study was made of how the tribological behaviour of implanted steels changes with different implantation parameters. The tribological laboratory investigations were carried out using pin-on-disc equipment under controlled test conditions, and deal with high dose carbon implantation (approximately (1-2)x10 18 ions cm -2 ). The wear resistance of steels was enhanced dramatically, by up to several orders of magnitude. The field test results cover a broad range of ion implanted production tools, which showed a marked improvement in wear resistance. Nitrogen implanted tools are also compared with carbon and titanium implanted tools. (orig.)

Wear resistance of nano- and micro-crystalline diamond coatings onto WC-Co with Cr/CrN interlayers

Energy Technology Data Exchange (ETDEWEB)

Polini, Riccardo [Dipartimento di Scienze e Tecnologie Chimiche, Universita di Roma Tor Vergata, Via della Ricerca Scientifica, 1, Rome, 00133 (Italy); Barletta, Massimiliano, E-mail: barletta@ing.uniroma2.i [Dipartimento di Ingegneria Meccanica, Universita di Roma Tor Vergata, Via del Politecnico, 1, Rome, 00133 (Italy); Cristofanilli, Giacomo [Dipartimento di Scienze e Tecnologie Chimiche, Universita di Roma Tor Vergata, Via della Ricerca Scientifica, 1, Rome, 00133 (Italy)

2010-12-30

Cr/CrN bi-layers have been used recently to promote the growth of high quality Hot Filament Chemical Vapour Deposition (HFCVD) diamond coatings onto Co-cemented tungsten carbide (WC-6 wt.%Co) substrates. In the present investigation, the influence of the crystalline size of the diamond coatings on their wear endurance is looked into. Nano- (NDC) and micro-crystalline Diamond Coatings (MDC) were deposited by HFCVD onto untreated and Fluidized Bed (FB) treated Cr/CrN interlayers. NDCs, characterized by a cauliflower-like morphology, showed improved wear resistance. However, the superimposition of NDCs onto Cr/CrN interlayers micro-corrugated by FB treatment was found to be the most promising choice, leading to the formation of highly adherent and wear resistant coatings.

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.

Improving the Wear Resistance of Moulds for the Injection of Glass Fibre–Reinforced Plastics Using PVD Coatings: A Comparative Study

Directory of Open Access Journals (Sweden)

Francisco Silva

2017-02-01

Full Text Available It is well known that injection of glass fibre–reinforced plastics (GFRP causes abrasive wear in moulds’ cavities and runners. Physical vapour deposition (PVD coatings are intensively used to improve the wear resistance of different tools, also being one of the most promising ways to increase the moulds’ lifespan, mainly when used with plastics strongly reinforced with glass fibres. This work compares four different thin, hard coatings obtained using the PVD magnetron sputtering process: TiAlN, TiAlSiN, CrN/TiAlCrSiN and CrN/CrCN/DLC. The first two are monolayer coatings while the last ones are nanostructured and consist of multilayer systems. In order to carry out the corresponding tribological characterization, two different approaches were selected: A laboratorial method, using micro-abrasion wear tests based on a ball-cratering configuration, and an industrial mode, analysing the wear resistance of the coated samples when inserted in a plastic injection mould. As expected, the wear phenomena are not equivalent and the results between micro-abrasion and industrial tests are not similar due to the different means used to promote the abrasion. The best wear resistance performance in the laboratorial wear tests was attained by the TiAlN monolayer coating while the best performance in the industrial wear tests was obtained by the CrN/TiAlCrSiN nanostructured multilayer coating.

Ceramics in Restorative and Prosthetic DENTISTRY1

Science.gov (United States)

Kelly, J. Robert

1997-08-01

This review is intended to provide the ceramic engineer with information about the history and current use of ceramics in dentistry, contemporary research topics, and potential research agenda. Background material includes intra-oral design considerations, descriptions of ceramic dental components, and the origin, composition, and microstructure of current dental ceramics. Attention is paid to efforts involving net-shape processing, machining as a forming method, and the analysis of clinical failure. A rationale is presented for the further development of all-ceramic restorative systems. Current research topics receiving attention include microstructure/processing/property relationships, clinical failure mechanisms and in vitro testing, wear damage and wear testing, surface treatments, and microstructural modifications. The status of the field is critically reviewed with an eye toward future work. Significant improvements seem possible in the clinical use of ceramics based on engineering solutions derived from the study of clinically failed restorations, on the incorporation of higher levels of "biomimicry" in new systems, and on the synergistic developments in dental cements and adhesive dentin bonding.

Wear performance of garnet aluminium composites at high contact pressure

Science.gov (United States)

Sharma, Anju; Arora, Rama; Kumar, Suresh; Singh, Gurmel; Pandey, O. P.

2016-05-01

To satisfy the needs of the engineering sector, researchers and material scientists in this area adopted the development of composites with tailor made properties to enhance efficiency and cost savings in the manufacturing sector. The technology of the mineral industry is shaping the supply and demand of minerals derived materials. The composites are best classified as high performance materials have high strength-to-weight ratios, and require controlled manufacturing environments for optimum performance. Natural mineral garnet was used as the reinforcement of composite because of satisfactory mechanical properties as well as an attractive ecological alternative to others ceramics. For this purpose, samples have been prepared with different sizesof the garnet reinforcement using the mechanical stirring method to achieve the homogeneously dispersed strengthening phase. A systematic study of the effect of high contact pressure on the sliding wear behaviour of garnet reinforced LM13 alloy composites is presented in this paper. The SEM analysis of the worn samples and debris reveals the clues about the wear mechanism. The drastic improvement in the wear resistance of the composites at high contact pressure shows the high potential of the material to be used in engineering applications.

Wear Performance of Sequentially Cross-Linked Polyethylene Inserts against Ion-Treated CoCr, TiNbN-Coated CoCr and Al2O3 Ceramic Femoral Heads for Total Hip Replacement

Directory of Open Access Journals (Sweden)

Christian Fabry

2015-02-01

Full Text Available The aim of the present study was to evaluate the biotribology of current surface modifications on femoral heads in terms of wettability, polyethylene wear and ion-release behavior. Three 36 mm diameter ion-treated CoCr heads and three 36 mm diameter TiNbN-coated CoCr heads were articulated against sequentially cross-linked polyethylene inserts (X3 in a hip joint simulator, according to ISO 14242. Within the scope of the study, the cobalt ion release in the lubricant, as well as contact angles at the bearing surfaces, were investigated and compared to 36 mm alumina ceramic femoral heads over a period of 5 million cycles. The mean volumetric wear rates were 2.15 ± 0.18 mm3·million cycles−1 in articulation against the ion-treated CoCr head, 2.66 ± 0.40 mm3·million cycles−1 for the coupling with the TiNbN-coated heads and 2.17 ± 0.40 mm3·million cycles−1 for the ceramic heads. The TiNbN-coated femoral heads showed a better wettability and a lower ion level in comparison to the ion-treated CoCr heads. Consequently, the low volumes of wear debris, which is comparable to ceramics, and the low concentration of metal ions in the lubrication justifies the use of coated femoral heads.

Wear resistance and electrical properties of functionally graded epoxy-resin/silica composites

International Nuclear Information System (INIS)

Rihan, Y. A.; Abd El-Bary, B.

2012-12-01

In this paper graded Silica/Epoxy composite fabricated by controlled mold filling to obtain a stepwise graded structure. The generated graded structure was controlled by the w 1% content of silica particulates of size range from (45 μm-250 μm). Microstructural characterization was conducted using Scanning Electron Microscope (SEM). Electrical properties were conducted in High Voltage-Lab using Sphere-Plate Electrode System and Insulating resistance equipment s. Wear characteristics were studied using Block-on-Ring wear testing machine for the different layers of the graded silica/epoxy composites, The prepared materials are used as coating materials for the floors of chemical laboratories. (Author)

Influence of temperature and heat treatment on crack resistance of ceramic tungsten

International Nuclear Information System (INIS)

Uskov, E.I.; Babak, A.V.; Bega, N.D.

1983-01-01

The effect of testing temperature in the range from 20 to 2000 deg C, and recrystallization annealing at 2200 deg C on crack resistance of ceramic tungsten in vacuum, is investigated. The extension diagrams thus obtained have been treated in accordance with the standard technique. The value of the critical crack loading and the stress intensity coefficient have been determined. Structural changes have been controlled with X-ray structural methods. Crack resistance of tungsten increases in the test temperature range from 20 deg C to Tsub(x) which is connected with the increase of mobility of screw components of dislocation loops. At the temperature more than Tsub(x) the plasticity growth of ceramic tungsten takes place simultaneously with grain boundary embrittlement. Recrystallization annealing at 2200 deg C creates the structure resistant to temperature effect; crack resistance being minimum

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

Science.gov (United States)

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

2017-05-01

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

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

International Nuclear Information System (INIS)

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

2017-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-08-30

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

Friction and wear behavior of glasses and ceramics

Science.gov (United States)

Buckley, D. H.

1973-01-01

Adhesion, friction, and wear behavior of glasses and ionic solids are reviewed. These materials are shown to behave in a manner similar to other solids with respect to adhesion. Their friction characteristics are shown to be sensitive to environmental constituents and surface films. This sensitivity can be related to a reduction in adhesive bonding and the changes in surficial mechanical behavior associated with Rehbinder and Joffe effects. Both friction and wear properties of ionic crystalline solids are highly anisotropic. With metals in contact with ionic solids the fracture strength of the ionic solid and the shear strength in the metal and those properties that determine these will dictate which of the materials undergoes adhesive wear. The chemical activity of the metal plays an important role in the nature and strength of the adhesive interfacial bond that develops between the metal and a glass or ionic solid.

The enhancement in wear resistance of W18Cr4V steel by ion implantation

International Nuclear Information System (INIS)

Zhou Ping; Xu Peiguang

1987-01-01

Two new methods of ion implantation were adopted in comparison with nitrogen implantation: carbon monoxide was implanted directly into W18Cr4V steel, and nitrogen was implanted into a deposited titanium film about 1000 A thick. It is shown that higher surface hardness and wear resistance have been achieved. The composition and phase structure of the implanted layer was determined in detail. The wear mechanisms were discussed

The effects of different polishing techniques on the staining resistance of CAD/CAM resin-ceramics

Science.gov (United States)

Demirci, Tevfik; Demirci, Gamze; Sagsoz, Nurdan Polat; Yildiz, Mehmet

2016-01-01

PURPOSE The purposes of this study were to evaluate the staining resistance of CAD/CAM resin-ceramics polished with different techniques and to determine the effectiveness of the polishing techniques on resin-ceramics, comparing it with that of a glazed glass-ceramic. MATERIALS AND METHODS Four different CAD/CAM ceramics (feldspathic ceramic: C-CEREC Blocs, (SIRONA) and three resin-ceramics: L-Lava Ultimate, (3M ESPE), E-Enamic, (VITA) and CS-CeraSmart, (GC)) and one light cure composite resin: ME-Clearfil Majesty Esthetic (Kuraray) were used. Only C samples were glazed (gl). Other restorations were divided into four groups according to the polishing technique: nonpolished control group (c), a group polished with light cure liquid polish (Biscover LV BISCO) (bb), a group polished with ceramic polishing kit (Diapol, EVE) (cd), and a group polished with composite polishing kit (Clearfil Twist Dia, Kuraray) (kc). Glazed C samples and the polished samples were further divided into four subgroups and immersed into different solutions: distilled water, tea, coffee, and fermented black carrot juice. Eight samples (8 × 8 × 1 mm) were prepared for each subgroup. According to CIELab system, four color measurements were made: before immersion, immersion after 1 day, after 1 week, and after 1 month. Data were analyzed with repeated measures of ANOVA (α=.05). RESULTS The highest staining resistance was found in gl samples. There was no difference among gl, kc and cd (P>.05). Staining resistance of gl was significantly higher than that of bb (PCeramic and composite polishing kits can be used for resin ceramics as a counterpart of glazing procedure used for full ceramic materials. Liquid polish has limited indications for resin ceramics. PMID:28018558

Fatigue resistance of 2 different CAD/CAM glass-ceramic materials used for single-tooth implant crowns.

Science.gov (United States)

Çavuşoğlu, Yeliz; Sahin, Erdal; Gürbüz, Riza; Akça, Kivanç

2011-10-01

To evaluate the fatigue resistance of 2 different CAD/CAM in-office monoceramic materials with single-tooth implant-supported crowns in functional area. A metal experimental model with a dental implant was designed to receive in-office CAD/CAM-generated monoceramic crowns. Laterally positioned axial dynamic loading of 300 N at 2 Hz was applied to implant-supported crowns machined from 2 different glass materials for 100,000 cycle. Failures in terms of fracture, crack formation, and chipping were macroscopically recorded and microscopically evaluated. Four of 10 aluminasilicate glass-ceramic crowns fractured at early loading cycles, the rest completed loading with a visible crack formation. Crack formation was recorded for 2 of 10 leucite glass-ceramic crowns. Others completed test without visible damage but fractured upon removal. Lack in chemical adhesion between titanium abutment and dental cement likely reduces the fatigue resistance of machinable glass-ceramic materials. However, relatively better fractural strength of leucite glass-ceramics could be taken into consideration. Accordingly, progress on developmental changes in filler composition of glass-ceramics may be promising. Machinable glass-ceramics do not possess sufficient fatigue resistance for single-tooth implant crowns in functional area.

DEVELOPMENT OF LASER CLADDING WEAR-RESISTANT COATING ON TITANIUM ALLOYS

OpenAIRE

RUILIANG BAO; HUIJUN YU; CHUANZHONG CHEN; BIAO QI; LIJIAN ZHANG

2006-01-01

Laser cladding is an advanced surface modification technology with broad prospect in making wear-resistant coating on titanium alloys. In this paper, the influences of laser cladding processing parameters on the quality of coating are generalized as well as the selection of cladding materials on titanium alloys. The microstructure characteristics and strengthening mechanism of coating are also analyzed. In addition, the problems and precaution measures in the laser cladding are pointed out.

Assessment of the State of the Art of Ultra High Temperature Ceramics

Science.gov (United States)

Johnson, Sylvia; Gasch, Matt; Stackpoole, Mairead

2009-01-01

Ultra High Temperature Ceramics (UHTCs) are a family of materials that includes the borides, carbides and nitrides of hafnium-, zirconium- and titanium-based systems. UHTCs are famous for possessing some of the highest melting points of known materials. In addition, they are very hard, have good wear resistance, mechanical strength, and relatively high thermal conductivities (compared to other ceramic materials). Because of these attributes, UHTCs are ideal for thermal protection systems, especially those that require chemical and structural stability at extremely high operating temperatures. UHTCs have the potential to revolutionize the aerospace industry by enabling the development of sharp hypersonic vehicles or atmospheric entry probes capable of the most extreme entry conditions.

Fiscal 1997 report of the R and D result of industrial science and technology. R and D on synergy ceramics (development of rational energy use technology); 1997 nendo sangyo kagaku gijutsu kenkyu kaihatsu seika hokokusho. Synergy ceramics no kenkyu kaihatsu (energy shiyo gorika gijutsu kaihatsu)

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

For rational use of energy resources, the process technology which allows harmonization and multiplication of conflicting characteristics was developed for development of new ceramic system materials. This paper summarizes the result in fiscal 1997. On a structural reaction process among creation technologies of ultra-reliable structure, study was made on structure control and hot-working technology through atmosphere control in ceramics synthesis. On basic technology for analysis and evaluation, study was made on the effect of particle bridging on strengthening and toughening of ceramic materials. Study was also made on a toughness expression mechanism, FEM model analysis of particle bridging, and crack growth resistance of ceramics. On control of solid solution precipitation, new alumina ceramics with high strength, hardness and wear resistance was obtained by transgranularly precipitating nano-size particles from a fine-grain high-density matrix through an improved particle formation process. Its toughness was considerably improved by controlling grain shape and grain boundary structure. A precipitation mechanism was also discussed. 89 refs., 107 figs., 14 tabs.

Chemically robust carbon nanotube–PTFE superhydrophobic thin films with enhanced ability of wear resistance

Institute of Scientific and Technical Information of China (English)

Kewei Wang; Pan Xiong; Xiuping Xu; Kan Wang; YanLong Li; Yufeng Zheng

2017-01-01

A chemically robust superhydrophobic nanocomposite thin film with enhanced wear resistance is prepared from a composite comprising polytetrafluoroethylene (PTFE) and carbon nanotubes. The superhydrophobic thin films with hierarchical structure are fabricated by spraying an environmentally friendly aqueous dispersion containing carbon nanotubes and PTFE resin on silicon wafer. Thin films with a contact angle of 154.1° ± 2° and a sliding angle less than 2° remain superhydrophobic after abrading over 500 times under a pressure of 50 g/cm2. The thin film is also extremely stable even under much stress conditions. To further the understanding of the enhancement of wear resistance, we investigated the formation of microsized structure and their effects. The growth of microbumps is caused by attracting solution droplet to the hydrophilic islands on hydrophobic surface.

Phase constituents and microstructure of laser cladding Al2O3/Ti3Al reinforced ceramic layer on titanium alloy

International Nuclear Information System (INIS)

Li Jianing; Chen Chuanzhong; Lin Zhaoqing; Squartini, Tiziano

2011-01-01

Research highlights: → In this study, Fe 3 Al has been chosen as cladding powder due to its excellent properties of wear resistance and high strength, etc. → Laser cladding of Fe 3 Al + TiB 2 /Al 2 O 3 pre-placed alloy powder on Ti-6Al-4V alloy substrate can form the Ti 3 Al/Fe 3 Al + TiB 2 /Al 2 O 3 ceramic layer, which can increase wear resistance of substrate. → In cladding process, Al 2 O 3 can react with TiB 2 leading to formation of Ti 3 Al and B. → This principle can be used to improve the Fe 3 Al + TiB 2 laser-cladded coating. - Abstract: Laser cladding of the Fe 3 Al + TiB 2 /Al 2 O 3 pre-placed alloy powder on Ti-6Al-4V alloy can form the Ti 3 Al/Fe 3 Al + TiB 2 /Al 2 O 3 ceramic layer, which can greatly increase wear resistance of titanium alloy. In this study, the Ti 3 Al/Fe 3 Al + TiB 2 /Al 2 O 3 ceramic layer has been researched by means of electron probe, X-ray diffraction, scanning electron microscope and micro-analyzer. In cladding process, Al 2 O 3 can react with TiB 2 leading to formation of amount of Ti 3 Al and B. This principle can be used to improve the Fe 3 Al + TiB 2 laser cladded coating, it was found that with addition of Al 2 O 3 , the microstructure performance and micro-hardness of the coating was obviously improved due to the action of the Al-Ti-B system and hard phases.

Ultralight and fire-resistant ceramic nanofibrous aerogels with temperature-invariant superelasticity.

Science.gov (United States)

Si, Yang; Wang, Xueqin; Dou, Lvye; Yu, Jianyong; Ding, Bin

2018-04-01

Ultralight aerogels that are both highly resilient and compressible have been fabricated from various materials including polymer, carbon, and metal. However, it has remained a great challenge to realize high elasticity in aerogels solely based on ceramic components. We report a scalable strategy to create superelastic lamellar-structured ceramic nanofibrous aerogels (CNFAs) by combining SiO 2 nanofibers with aluminoborosilicate matrices. This approach causes the random-deposited SiO 2 nanofibers to assemble into elastic ceramic aerogels with tunable densities and desired shapes on a large scale. The resulting CNFAs exhibit the integrated properties of flyweight densities of >0.15 mg cm -3 , rapid recovery from 80% strain, zero Poisson's ratio, and temperature-invariant superelasticity to 1100°C. The integral ceramic nature also provided the CNFAs with robust fire resistance and thermal insulation performance. The successful synthesis of these fascinating materials may provide new insights into the development of ceramics in a lightweight, resilient, and structurally adaptive form.

Bioactive glass–ceramic coating for enhancing the in vitro corrosion resistance of biodegradable Mg alloy

International Nuclear Information System (INIS)

Ye Xinyu; Cai Shu; Dou Ying; Xu Guohua; Huang Kai; Ren Mengguo; Wang Xuexin

2012-01-01

Highlights: ► Sol–gel derived 45S5 glass–ceramic coating was prepared on Mg alloy substrate. ► The corrosion resistance of glass–ceramic coated Mg alloy was markedly improved. ► The corrosion behavior of the coated sample varied due to the cracking of coating. - Abstract: In this work, a bioactive 45S5 glass–ceramic coating was synthesized on magnesium (Mg) alloy substrate by using a sol–gel dip-coating method, to improve the initial corrosion resistance of AZ31 Mg alloy. The surface morphology and phase composition of the glass–ceramic coating were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The coating composed of amorphous phase and crystalline phase Na 2 Ca 2 Si 3 O 9 , with the thickness of ∼1.0 μm, exhibited a uniform and crack-free surface morphology. The corrosion behavior of the uncoated and coated Mg alloy substrates was investigated by the electrochemical measurements and immersion tests in simulated body fluid (SBF). Potentiodynamic polarization tests recorded an increase of potential (E corr ) form −1.60 V to −1.48 V, and a reduction of corrosion current density (i corr ) from 4.48 μA cm −2 to 0.16 μA cm −2 , due to the protection provided by the glass–ceramic coating. Immersion tests also showed the markedly improved corrosion resistance of the coated sample over the immersion period of 7 days. Moreover, after 14 days of immersion in SBF, the corrosion resistance of the coated sample declined due to the cracking of the glass–ceramic coating, which was confirmed by electrochemical impedance spectroscopy (EIS) analysis. The results suggested that the 45S5 glass–ceramic coated Mg alloy could provide a suitable corrosion behavior for use as degradable implants.

Standard Test Method for Abrasive Wear Resistance of Cemented

CERN Document Server

American Society for Testing and Materials. Philadelphia

2005-01-01

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

Studies of valve lifter for automotive heavy duty diesel engine by ceramic materials. II. Development of SiC valve lifter by injection molding method

Energy Technology Data Exchange (ETDEWEB)

Yun, H W [Technical Centre of KIA-ASIA MOTORS (Korea, Republic of); Han, I S [Korea Institute of Energy Research, Tajeon (Korea, Republic of); Lim, Y S; Chung, Y J [Myong Ji University (Korea, Republic of)

1998-02-01

Valve lifter, namely tappet, is supported by lifter hole which is located upper side of camshaft in cylinder block, transforms rotatic movement of camshaft into linear movement and helps to open and shut the engine valve as an engine parts. The face of valve lifter, which is continuously contacting with camshaft, brings about abnormal wears, such as unfair wear and early wear, because it is severely loaded in the valve train system. These wears act as a defect like over-clearance and cause imperfect combustion of fuel during the valve lifting in the combustion chamber. Consequently, this imperfect combustion makes the engine out-put decrease and has cause on air pollution. To prevent these wears, therefore, the valve lifter cast in metal developed into SiC ceramics valve lifter which has an excellence in wear and impact resistance. As a result, the optimum process conditions like injection condition, mixture ratio and debonding process could be established. After sintering, fine-sinered dual microstructure in which prior {alpha}-SiC, carbon and silicon was obtained. Based on the new SiC({beta}-SiC) produced by reaction among the {alpha}-SiC, carbon and silicon was obtained. Based on the study, it is verified that mechanical properties of SiC valve lifter are excellent in Vickers hardness 1100{approx}1200 bending strength (300{approx}350 Pa), fracture toughness (1.5{approx}1.7 MPacentre dotm{sup 1/2}). Through engine dynamo testing, SiC valve lifter and metal valve lifter are examined and compared into abnormal phenomena such early fracture, unfair and early wear. It is hoped that this research will serve as an important springboard for the future study of heavy duty diesel engine parts developed by ceramics which has a good wear resistance, reliability, and lightability.

Wear resistant PTFE thin film enabled by a polydopamine adhesive layer

International Nuclear Information System (INIS)

Beckford, Samuel; Zou, Min

2014-01-01

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

The use of ion implantation for the improvement of abrasive wear resistance

International Nuclear Information System (INIS)

Delves, B.G.; Dearnaley, G.

1979-01-01

At the conclusion of the 1977 IPAT conference a practical problem was described which called for an economically feasible method of improving the resistance of tool steel, chromium and other alloys to abrasive wear sustained during the injection moulding of phenolic resin. This paper will describe subsequent work to investigate ion implantation as a possible means of treating steel taps, injection nozzles, feed wear pads, cavity moulds etc. Various problems were encountered and it will be described how most of these have now been overcome. Under favourable conditions factors of 4, and sometimes up to 10 times the normal life can be achieved. An attempt will be made to estimate some of the economic benefits of the process. (author)

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

Directory of Open Access Journals (Sweden)

J.O. Agunsoye

2015-03-01

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

On the influence of Ti-Al intermetallic coating architecture on mechanical properties and wear resistance of end mills

Science.gov (United States)

Vardanyan, E. L.; Budilov, V. V.; Ramazanov, K. N.; Ataullin, Z. R.

2017-07-01

Thin-film wear-resistant coatings are widely used to increase life and efficiency of metal cutting tools. This paper shows the results of a study on the influence of architecture (number, sequence and thickness of layers) of wear-resistant coatings on physical, mechanical and operational properties of end mills. Coatings consisting of alternating Ti-Al/Ti-Al-N layers of equal thickness demonstrated the best physical and mechanical properties. Durability of coated tools when processing materials from chromium-vanadium steel increased twice as compared to uncoated tools.

Effect of cobalt content on wear and corrosion behaviors of electrodeposited Ni-Co/WC nano-composite coatings.

Science.gov (United States)

Amadeh, A; Ebadpour, R

2013-02-01

Metal-ceramic composite coatings are widely used in automotive and aerospace industries as well as micro-electronic systems. Electrodeposition is an economic method for application of these coatings. In this research, nickel-cobalt coatings reinforced by nano WC particles were applied on carbon steel substrate by pulse electrodeposition from modified Watts bath containing different amounts of cobalt sulphate as an additive. Saccharin and sodium dodecyl sulphate (SDS) were also added to electroplating bath as grain refiner and surfactant, respectively. The effect of cobalt content on wear and corrosion behavior of the coatings was investigated. Wear and corrosion properties were assessed by pin-on-disk and potentiodynamic polarization methods, respectively. Phase analysis was performed by X-ray diffraction (XRD) using CuK(alpha) radiation and the worn surfaces were studied by means of Scanning Electron Microscopy (SEM). The results showed that the addition of cobalt improved the wear resistance of the coatings. In the presence of 18 g/L cobalt in electrodeposition bath, the wear rate of the coating decreased to 0.002 mg/m and the coefficient of friction reduced to 0.695 while they were 0.004 mg/m and 0.77 in the absence of cobalt, respectively. This improvement in wear properties can be attributed to the formation of hcp phase in metallic matrix. Meanwhile, the corrosion resistance of the coatings slightly reduced because cobalt is more active metal with respect to nickel.

Bioactive and inert dental glass-ceramics.

Science.gov (United States)

Montazerian, Maziar; Zanotto, Edgar Dutra

2017-02-01

The global market for dental materials is predicted to exceed 10 billion dollars by 2020. The main drivers for this growth are easing the workflow of dentists and increasing the comfort of patients. Therefore, remarkable research projects have been conducted and are currently underway to develop improved or new dental materials with enhanced properties or that can be processed using advanced technologies, such as CAD/CAM or 3D printing. Among these materials, zirconia, glass or polymer-infiltrated ceramics, and glass-ceramics (GCs) are of great importance. Dental glass-ceramics are highly attractive because they are easy to process and have outstanding esthetics, translucency, low thermal conductivity, high strength, chemical durability, biocompatibility, wear resistance, and hardness similar to that of natural teeth, and, in certain cases, these materials are bioactive. In this review article, we divide dental GCs into the following two groups: restorative and bioactive. Most restorative dental glass-ceramics (RDGCs) are inert and biocompatible and are used in the restoration and reconstruction of teeth. Bioactive dental glass-ceramics (BDGCs) display bone-bonding ability and stimulate positive biological reactions at the material/tissue interface. BDGCs are suggested for dentin hypersensitivity treatment, implant coating, bone regeneration and periodontal therapy. Throughout this paper, we elaborate on the history, processing, properties and applications of RDGCs and BDGCs. We also report on selected papers that address promising types of dental glass-ceramics. Finally, we include trends and guidance on relevant open issues and research possibilities. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 619-639, 2017. © 2016 Wiley Periodicals, Inc.

Optimizing Wear Resistance and Impact Toughness in High Chromium Iron Mo-Ni Alloy

Science.gov (United States)

Singh, K. K.; Verma, R. S.; Murty, G. M. D.

2009-06-01

An alloy with carbon and chromium in the range of 2.0 to 2.5% and 20 to 25%, respectively, with the addition of Mo and Ni in the range of 1.0 to 1.5% each when heat-treated at a quenching temperature of 1010 °C and tempering temperature of 550 °C produces a hardness in the range of 54 to 56 HRC and a microstructure that consists of discontinuous bands of high volume (35-40%) of wear resistant primary (eutectic) carbides in a tempered martensitic matrix with uniformly dispersed secondary precipitates. This alloy has been found to possess adequate impact toughness (5-6 J/cm2) with a wear resistance of the order of 3-4 times superior to Mn steel and 1.25 times superior to martensitic stainless steel with a reduction in cost-to-life ratio by a factor of 1.25 in both the cases.

Corrosion resistant ceramic materials

Science.gov (United States)

Kaun, T.D.

1996-07-23

Ceramic materials are disclosed which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200--550 C or organic salt (including SO{sub 2} and SO{sub 2}Cl{sub 2}) at temperatures of 25--200 C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components. 1 fig.

Corrosion resistant ceramic materials

Science.gov (United States)

Kaun, Thomas D.

1996-01-01

Ceramic materials which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200.degree.-550.degree. C. or organic salt (including SO.sub.2 and SO.sub.2 Cl.sub.2) at temperatures of 25.degree.-200.degree. C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components.

Fracture Resistance and Mode of Failure of Ceramic versus Titanium Implant Abutments and Single Implant-Supported Restorations.

Science.gov (United States)

Sghaireen, Mohd G

2015-06-01

The material of choice for implant-supported restorations is affected by esthetic requirements and type of abutment. This study compares the fracture resistance of different types of implant abutments and implant-supported restorations and their mode of failure. Forty-five Oraltronics Pitt-Easy implants (Oraltronics Dental Implant Technology GmbH, Bremen, Germany) (4 mm diameter, 10 mm length) were embedded in clear autopolymerizing acrylic resin. The implants were randomly divided into three groups, A, B and C, of 15 implants each. In group A, titanium abutments and metal-ceramic crowns were used. In group B, zirconia ceramic abutments and In-Ceram Alumina crowns were used. In group C, zirconia ceramic abutments and IPS Empress Esthetic crowns were used. Specimens were tested to failure by applying load at 130° from horizontal plane using an Instron Universal Testing Machine. Subsequently, the mode of failure of each specimen was identified. Fracture resistance was significantly different between groups (p Empress crowns supported by zirconia abutments had the lowest fracture loads (p = .000). Fracture modes of metal-ceramic crowns supported by titanium abutments included screw fracture and screw bending. Fracture of both crown and abutment was the dominant mode of failure of In-Ceram/IPS Empress crowns supported by zirconia abutments. Metal-ceramic crowns supported by titanium abutments were more resistant to fracture than In-Ceram crowns supported by zirconia abutments, which in turn were more resistant to fracture than IPS Empress crowns supported by zirconia abutments. In addition, failure modes of restorations supported by zirconia abutments were more catastrophic than those for restorations supported by titanium abutments. © 2013 Wiley Periodicals, Inc.

Effect of an edge at cup rim on contact stress during micro-separation in ceramic-on-ceramic hip joints.

Science.gov (United States)

Liu, Feng; Fisher, John

2017-09-01

Alumina ceramic total hip joint bearings have shown superior wear properties. The joint bearing may undergo adverse conditions such as micro-separation causing head contact on the cup rim. As a transition, an edge is formed between the cup bearing and the rim. The aim of this study was to predict the effect of the edge on contact stresses in order to better understand the mechanisms of wear. A finite element contact model was developed under the conditions of the head displacements 0.5-2 mm and vertical loads 0.5-3 kN. The edge contact produced the most severe stresses capable of causing elevated wear and damage to ceramic bearings. The study shows that the bearing design should be considered in association with clinical conditions to eliminate severe stress.

Alternate paddle configuration for improved wear resistance in the saltstone mixer

Energy Technology Data Exchange (ETDEWEB)

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

2013-09-23

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

Effects of a dynamic confinement on the penetration resistance of ceramics against long rods

International Nuclear Information System (INIS)

Malaise, Frederic; Tranchet, Jean-Yves; Collombet, Francis

2000-01-01

Adequate confinement of a ceramic block can lead to its impenetrability against long rod penetrators. New ballistic experiments (encapsulated rod experiments) enabling a pressurization of the front face of the ceramic block (dynamic confinement) have been performed and compared to results obtained from standard unconfined configurations (DOP tests). Impenetrability of the ceramic block is obtained with the encapsulated rod configuration. A modeling approach based on a description of the fragmentation process of the ceramic is proposed. In particular, effects of the void content of the fragmented ceramic on its shear resistance are taken into account. Comparisons between Eulerian computation and the experiments show that conditions for rod dwell are linked to immobilizing fragments of ceramic in front of the projectile

Hybrid metallic nanocomposites for extra wear-resistant diamond machining tools

DEFF Research Database (Denmark)

Loginov, P.A.; Sidorenko, D.A.; Levashov, E.A.

2018-01-01

The applicability of metallic nanocomposites as binder for diamond machining tools is demonstrated. The various nanoreinforcements (carbon nanotubes, boron nitride hBN, nanoparticles of tungsten carbide/WC) and their combinations are embedded into metallic matrices and their mechanical properties...... are determined in experiments. The wear resistance of diamond tools with metallic binders modified by various nanoreinforcements was estimated. 3D hierarchical computational finite element model of the tool binder with hybrid nanoscale reinforcements is developed, and applied for the structure...

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

International Nuclear Information System (INIS)

Chan, Chi-Wai; Lee, Seunghwan; Smith, Graham; Sarri, Gianluca; Ng, Chi-Ho; Sharba, Ahmed; Man, Hau-Chung

2016-01-01

Graphical abstract: - Highlights: • Laser technology is a fast, clean and flexible method for surface hardening of TNZT. • Laser can form a protective hard layer on TNZT surface without altering surface roughness. • The laser-formed layer is metallurgically bonded to the substrate. • Laser-treated TNZT is highly resistant to corrosion and wear in Hank's solution. - Abstract: The relatively high elastic modulus coupled with the presence of toxic vanadium (V) in Ti6Al4V alloy has long been a concern in orthopaedic applications. To solve the problem, a variety of non-toxic and low modulus beta-titanium (beta-Ti) alloys have been developed. Among the beta-Ti alloy family, the quaternary Ti–Nb–Zr–Ta (TNZT) alloys have received the highest attention as a promising replacement for Ti6Al4V due to their lower elastic modulus and outstanding long term stability against corrosion in biological environments. However, the inferior wear resistance of TNZT is still a problem that must be resolved before commercialising in the orthopaedic market. In this work, a newly developed laser surface treatment technique was employed to improve the surface properties of Ti–35.3Nb–7.3Zr–5.7Ta alloy. The surface structure and composition of the laser-treated TNZT surface were examined by grazing incidence X-ray diffraction (GI-XRD) and X-ray photoelectron spectroscopy (XPS). The wear and corrosion resistance were evaluated by pin-on-plate sliding test and anodic polarisation test in Hanks’ solution. The experimental results were compared with the untreated (or base) TNZT material. The research findings showed that the laser surface treatment technique reported in this work can effectively improve the wear and corrosion resistance of TNZT.

What every surgeon should know about Ceramic-on-Ceramic bearings in young patients.

Science.gov (United States)

Hernigou, Philippe; Roubineau, François; Bouthors, Charlie; Flouzat-Lachaniette, Charles-Henri

2016-04-01

Based on the exceptional tribological behaviour and on the relatively low biological activity of ceramic particles, Ceramic-on-Ceramic (CoC) total hip arthroplasty (THA) presents significant advantagesCoC bearings decrease wear and osteolysis, the cumulative long-term risk of dislocation, muscle atrophy, and head-neck taper corrosion.However, there are still concerns regarding the best technique for implantation of ceramic hips to avoid fracture, squeaking, and revision of ceramic hips with fracture of a component.We recommend that surgeons weigh the potential advantages and disadvantages of current CoC THA in comparison with other bearing surfaces when considering young very active patients who are candidates for THA. Cite this article: Hernigou P, Roubineau F, Bouthors C, Flouzat-Lachaniette C-H. What every surgeon should know about Ceramic-on-Ceramic bearings in young patients. EFORT Open Rev 2016;1:107-111. DOI: 10.1302/2058-5241.1.000027.

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

Directory of Open Access Journals (Sweden)

O. S. Kobjakov

2008-01-01

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

Influence of deep cryogenic treatment on structure and wear resistance of materials of hydraulic breaker chisels

Science.gov (United States)

Bolobov, V. I.; BinhLe, Thanh

2018-03-01

It is shown that shallow cryogenic treatment at -75°C (SCT) of the materials of hydraulic breaker chisels - P20, 1080 and D2 steels leads to a decrease (44 ÷ 82%) in the amount of retained austenite and an increase (26 ÷ 99%) in the amount of carbides in the structure of hardened steel, which is accompanied by an increase in its hardness (1.4 ÷ 2.1%) and abrasive wear resistance (10 ÷ 31%) with a simultaneous decrease in impact toughness (19 ÷ 24%). Deep cryogenic treatment at -196°C (DCT) and subsequent low-temperature tempering of D2 steel leads to a significant increase in its wear resistance (98%) and impact toughness (32%).

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

Directory of Open Access Journals (Sweden)

Qingqiang Chen

2018-02-01

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

Effect of CeO₂ on Microstructure and Wear Resistance of TiC Bioinert Coatings on Ti6Al4V Alloy by Laser Cladding.

Science.gov (United States)

Chen, Tao; Liu, Defu; Wu, Fan; Wang, Haojun

2017-12-31

To solve the lack of wear resistance of titanium alloys for use in biological applications, various prepared coatings on titanium alloys are often used as wear-resistant materials. In this paper, TiC bioinert coatings were fabricated on Ti6Al4V by laser cladding using mixed TiC and ZrO₂ powders as the basic pre-placed materials. A certain amount of CeO₂ powder was also added to the pre-placed powders to further improve the properties of the TiC coatings. The effects of CeO₂ additive on the phase constituents, microstructures and wear resistance of the TiC coatings were researched in detail. Although the effect of CeO₂ on the phase constituents of the coatings was slight, it had a significant effect on the microstructure and wear resistance of the coatings. The crystalline grains in the TiC coatings, observed by a scanning electron microscope (SEM), were refined due to the effect of the CeO₂. With the increase of CeO₂ additive content in the pre-placed powders, finer and more compact dendrites led to improvement of the micro-hardness and wear resistance of the TiC coatings. Also, 5 wt % content of CeO₂ additive in the pre-placed powders was the best choice for improving the wear properties of the TiC coatings.

Application of Silicon Nitride (Si3N4 Ceramics in Ball Bearing

Directory of Open Access Journals (Sweden)

Wijianto Wijianto

2016-08-01

operation up to 1000°C, greater thermal shock resistance, lower density and low thermal expansion. This properties gives some benefit for ball bearing material such as higher running speed, reduce vibration of the shaft, will improve the life time and maintenance cost, lower heat generated, less energy consumption, lower wear rate, reducing noise level and reduce of using lubricant. The sintering methods are used to produce ball bearing from silicon nitride. Some techniques can be applied to increase ceramics strength which are reduce porosity, reduce grain size, reduce surface flaw and proof stressing. The surface finishing of the ceramic bearing is very important because silicon nitride as a brittle material, its strength is limited to the flaw sizes especially the flaw at the surface.

Nitriding the influence of plasma in resistance to wear micro abrasive tool steel AISI D2

International Nuclear Information System (INIS)

Gobbi, Vagner Joao; Gobb, Silvio Jose; Silva, Cosme Roberto Moreira da

2010-01-01

This work studies the influence of time of treatment in the formation of nitride layer of AISI D2 tool steel and the resistance to micro-abrasive wear from the technique of nitriding in plasma. The samples were nitrides at 400 ° C with a pressure of 4.5 mbar (450 Pa) and using a gas mixture of 80% vol.H2 and 20% vol.N2. The times of treatment were: 30, 60, 120, 180 and 360 minutes. The properties of the layers in the samples obtained nitrides were assessed by surface microhardness, profiles of microhardness, metallography analysis, X-ray diffraction and test for resistance to micro-abrasive wear. The best results for nitriding to 400 deg C, was obtained with the time of treatment of 360 minutes. In this case the increase in surface hardness was 94.6% and resistance to micro-abrasive wear of 15%. This increase in hardness may be associated with high concentration of nitrogen in the crystalline network of iron-α and additional training of nitrides. Low temperature of nitriding reduces between grain fragility to reduce the likelihood of precipitation of nitrides in a continuous manner in the austenite grain boundaries and the absence of previous ε'+ γ phases. (author)

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.

Bioactive glass-ceramic coating for enhancing the in vitro corrosion resistance of biodegradable Mg alloy

Energy Technology Data Exchange (ETDEWEB)

Ye Xinyu [Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University, Tianjin 300072 (China); Cai Shu, E-mail: caishu@tju.edu.cn [Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University, Tianjin 300072 (China); Dou Ying [Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University, Tianjin 300072 (China); Xu Guohua [Shanghai Changzheng Hospital, Shanghai 200003 (China); Huang Kai; Ren Mengguo; Wang Xuexin [Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University, Tianjin 300072 (China)

2012-10-15

Highlights: Black-Right-Pointing-Pointer Sol-gel derived 45S5 glass-ceramic coating was prepared on Mg alloy substrate. Black-Right-Pointing-Pointer The corrosion resistance of glass-ceramic coated Mg alloy was markedly improved. Black-Right-Pointing-Pointer The corrosion behavior of the coated sample varied due to the cracking of coating. - Abstract: In this work, a bioactive 45S5 glass-ceramic coating was synthesized on magnesium (Mg) alloy substrate by using a sol-gel dip-coating method, to improve the initial corrosion resistance of AZ31 Mg alloy. The surface morphology and phase composition of the glass-ceramic coating were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The coating composed of amorphous phase and crystalline phase Na{sub 2}Ca{sub 2}Si{sub 3}O{sub 9}, with the thickness of {approx}1.0 {mu}m, exhibited a uniform and crack-free surface morphology. The corrosion behavior of the uncoated and coated Mg alloy substrates was investigated by the electrochemical measurements and immersion tests in simulated body fluid (SBF). Potentiodynamic polarization tests recorded an increase of potential (E{sub corr}) form -1.60 V to -1.48 V, and a reduction of corrosion current density (i{sub corr}) from 4.48 {mu}A cm{sup -2} to 0.16 {mu}A cm{sup -2}, due to the protection provided by the glass-ceramic coating. Immersion tests also showed the markedly improved corrosion resistance of the coated sample over the immersion period of 7 days. Moreover, after 14 days of immersion in SBF, the corrosion resistance of the coated sample declined due to the cracking of the glass-ceramic coating, which was confirmed by electrochemical impedance spectroscopy (EIS) analysis. The results suggested that the 45S5 glass-ceramic coated Mg alloy could provide a suitable corrosion behavior for use as degradable implants.

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

Directory of Open Access Journals (Sweden)

VLASOV Vladimir Alexeevich

2014-08-01

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

Ceramic capacitor insulation resistance failures accelerated by low voltage

Science.gov (United States)

Brennan, T. F.

1978-01-01

Ceramic capacitors failed insulation resistance testing at less than one-tenth their rated voltage. Many failures recovered as the voltage was increased. Comprehensive failure analysis techniques, some of which are unprecedented, were used to examine these failures. It was determined that there was more than one failure mechanism, and the results indicate a need for special additional screening.

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

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

Directory of Open Access Journals (Sweden)

Chen Liqing

2015-01-01

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

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

Directory of Open Access Journals (Sweden)

Olejnik E.

2016-06-01

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

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

Surface depression of glass and surface swelling of ceramics induced by ion implantation

International Nuclear Information System (INIS)

Ikeyama, Masami; Saitoh, Kazuo; Nakao, Setsuo; Niwa, Hiroaki; Tanemura, Seita; Miyagawa, Yoshiko; Miyagawa, Souji

1994-01-01

By the measurement of the change of the surface shapes of the glass and ceramics in which ion implantation was performed, it was clarified that glass surface was depressed, and ceramic surface swelled. These depression and swelling changed according to the kinds of ions, energy and the amount to be implanted and the temperature of samples. It became clear that the depression of glass surface was nearly proportional to the range of flight of the implanted ions, and the swelling of ceramic surface showed different state in the silicon nitride with strong covalent bond and the alumina and sapphire with strong ionic bond. For the improvement of the mechanical characteristics of solid materials such as hardness, strength, toughness, wear resistance, oxidation resistance and so on, attention has been paid to the surface reforming by high energy ion implantation at MeV level. The change of shapes of base materials due to ion implantation is not always negligible. The experiment was carried out on sintered silicon nitride and alumina, polished sapphire single crystals and quartz glass. The experimental method and the results are reported. (K.I.)

Effect of CeO2 on Microstructure and Wear Resistance of TiC Bioinert Coatings on Ti6Al4V Alloy by Laser Cladding

Science.gov (United States)

Wang, Haojun

2017-01-01

To solve the lack of wear resistance of titanium alloys for use in biological applications, various prepared coatings on titanium alloys are often used as wear-resistant materials. In this paper, TiC bioinert coatings were fabricated on Ti6Al4V by laser cladding using mixed TiC and ZrO2 powders as the basic pre-placed materials. A certain amount of CeO2 powder was also added to the pre-placed powders to further improve the properties of the TiC coatings. The effects of CeO2 additive on the phase constituents, microstructures and wear resistance of the TiC coatings were researched in detail. Although the effect of CeO2 on the phase constituents of the coatings was slight, it had a significant effect on the microstructure and wear resistance of the coatings. The crystalline grains in the TiC coatings, observed by a scanning electron microscope (SEM), were refined due to the effect of the CeO2. With the increase of CeO2 additive content in the pre-placed powders, finer and more compact dendrites led to improvement of the micro-hardness and wear resistance of the TiC coatings. Also, 5 wt % content of CeO2 additive in the pre-placed powders was the best choice for improving the wear properties of the TiC coatings. PMID:29301218

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

Science.gov (United States)

2012-07-01

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

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

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

International Nuclear Information System (INIS)

Choi, Bong-Jae; Kim, Young-Jig; Sung, Si-Young

2012-01-01

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

Effects of applying an external magnetic field during the deep cryogenic heat treatment on the corrosion resistance and wear behavior of 1.2080 tool steel

International Nuclear Information System (INIS)

Akhbarizadeh, Amin; Amini, Kamran; Javadpour, Sirus

2012-01-01

Highlights: ► Deep cryogenic increases the carbide percentage and make a more homogenous distribution. ► Deep cryogenic improve the wear resistance and corrosion behavior of 1.2080 tool steel. ► Applying the magnetic field weaker the carbide distribution and decreases the carbides percentage. ► Magnetized samples showed weaker corrosion and wear behavior. -- Abstract: This work concerns with the effect of applying an external magnetic field on the corrosion behavior, wear resistance and microstructure of 1.2080 (D2) tool steel during the deep cryogenic heat treatment. These analyses were performed via scanning electron microscope (SEM), optical microscope (OM), transmission electron microscope (TEM) and X-ay diffraction (XRD) to study the microstructure, a pin-on-disk wear testing machine to study the wear behavior, and linear sweep voltammetry to study the corrosion behavior of the samples. It was shown that the deep cryogenic heat treatment eliminates retained austenite and makes a more uniform carbide distribution with higher percentage. It was also observed that the deep cryogenic heat treatment improves the wear behavior and corrosion resistance of 1.2080 tool steel. In comparison between the magnetized and non-magnetized samples, the carbide percentage decreases and the carbide distribution weakened in the magnetized samples; subsequently, the wear behavior and corrosion resistance attenuated compared in the magnetized samples.

Metallurgical/Alloy Optimization of High Strength and Wear Resistant Structural Quench and Tempered Steels

Science.gov (United States)

Stalheim, Douglas G.; Peimao, Fu; Linhao, Gu; Yongqing, Zhang

Structural steels with yield strength requirements greater or equal to 690 MPa can be produced through controlled recrystallization hot rolling coupled with precipitation strengthening or purposeful heat treatment through quench and tempering (Q&T). High strength structural steel and wear/abrasion resistant requirements greater or equal to 360 Brinell hardness (BHN) are produced by the development of microstructures of tempered lower bainite and/or martensite through the Q&T process. While these Q&T microstructures can produce very high strengths and hardness levels making them ideal for 690 MPa plus yield strength or wear/abrasion resistant applications, they lack toughness/ductility and hence are very brittle and prone to cracking. While tempering the microstructures helps in improving the toughness/ductility and reducing the brittleness, strength and hardness can be sacrificed. In addition, these steels typically consist of alloy designs containing boron with carbon equivalents (CE) greater than 0.50 to achieve the desired microstructures. The higher CE has a negative influence on weldability.

Investigation of piston ring – cylinder liner dry wear using a block-on-ring test rig

DEFF Research Database (Denmark)

Bihlet, Uffe; Klit, Peder; Felter, Christian L.

Characterization of the wear of piston rings and cylinder liner is an important aspect of large two stroke diesel engine design. Two major wear mechanisms exist; corrosive wear and mechanical wear. This paper deals with the most aggressive form of the latter, which is known as scuffing. Different...... that ceramic coating on the piston ring decreases the dry wear rate of both piston ring and liner, while the coefficient of friction is increased....

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.

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

Science.gov (United States)

Chan, Chi-Wai; Lee, Seunghwan; Smith, Graham; Sarri, Gianluca; Ng, Chi-Ho; Sharba, Ahmed; Man, Hau-Chung

2016-03-01

The relatively high elastic modulus coupled with the presence of toxic vanadium (V) in Ti6Al4V alloy has long been a concern in orthopaedic applications. To solve the problem, a variety of non-toxic and low modulus beta-titanium (beta-Ti) alloys have been developed. Among the beta-Ti alloy family, the quaternary Ti-Nb-Zr-Ta (TNZT) alloys have received the highest attention as a promising replacement for Ti6Al4V due to their lower elastic modulus and outstanding long term stability against corrosion in biological environments. However, the inferior wear resistance of TNZT is still a problem that must be resolved before commercialising in the orthopaedic market. In this work, a newly developed laser surface treatment technique was employed to improve the surface properties of Ti-35.3Nb-7.3Zr-5.7Ta alloy. The surface structure and composition of the laser-treated TNZT surface were examined by grazing incidence X-ray diffraction (GI-XRD) and X-ray photoelectron spectroscopy (XPS). The wear and corrosion resistance were evaluated by pin-on-plate sliding test and anodic polarisation test in Hanks' solution. The experimental results were compared with the untreated (or base) TNZT material. The research findings showed that the laser surface treatment technique reported in this work can effectively improve the wear and corrosion resistance of TNZT.

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

Directory of Open Access Journals (Sweden)

Gawdzińska K.

2016-03-01

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

Estimation of fracture conditions of ceramics by thermal shock with laser beams based on the maximum compressive stress criterion

International Nuclear Information System (INIS)

Akiyama, Shigeru; Amada, Shigeyasu.

1992-01-01

Structural ceramics are attracting attention in the development of space planes, aircraft and nuclear fusion reactors because they have excellent wear-resistant and heat-resistant characteristics. However, in some applications it is anticipated that they will be exposed to very-high-temperature environments of the order of thousands of degrees. Therefore, it is very important to investigate their thermal shock characteristics. In this report, the distributions of temperatures and thermal stresses of cylindrically shaped ceramics under irradiation by laser beams are discussed using the finite-element computer code (MARC) with arbitrary quadrilateral axisymmetric ring elements. The relationships between spot diameters of laser beams and maximum values of compressive thermal stresses are derived for various power densities. From these relationships, a critical fracture curve is obtained, and it is compared with the experimental results. (author)

Enhancement of the Wear Resistance and Microhardness of Aluminum Alloy by Nd:YaG Laser Treatment

Directory of Open Access Journals (Sweden)

Haitham T. Hussein

2014-01-01

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

Effects of Deep Cryogenic Treatment on the Wear Resistance and Mechanical Properties of AISI H13 Hot-Work Tool Steel

Science.gov (United States)

Çiçek, Adem; Kara, Fuat; Kıvak, Turgay; Ekici, Ergün; Uygur, İlyas

2015-11-01

In this study, a number of wear and tensile tests were performed to elucidate the effects of deep cryogenic treatment on the wear behavior and mechanical properties (hardness and tensile strength) of AISI H13 tool steel. In accordance with this purpose, three different heat treatments (conventional heat treatment (CHT), deep cryogenic treatment (DCT), and deep cryogenic treatment and tempering (DCTT)) were applied to tool steel samples. DCT and DCTT samples were held in nitrogen gas at -145 °C for 24 h. Wear tests were conducted on a dry pin-on-disk device using two loads of 60 and 80 N, two sliding velocities of 0.8 and 1 m/s, and a wear distance of 1000 m. All test results showed that DCT improved the adhesive wear resistance and mechanical properties of AISI H13 steel. The formation of small-sized and uniformly distributed carbide particles and the transformation of retained austenite to martensite played an important role in the improvements in the wear resistance and mechanical properties. After cleavage fracture, the surfaces of all samples were characterized by the cracking of primary carbides, while the DCT and DCTT samples displayed microvoid formation by decohesion of the fine carbides precipitated during the cryo-tempering process.

Scratch, wear and corrosion resistant organic inorganic hybrid materials for metals protection and barrier

International Nuclear Information System (INIS)

Barletta, M.; Gisario, A.; Puopolo, M.; Vesco, S.

2015-01-01

Highlights: • Polysiloxane coatings as protective barriers to delay erosion/corrosion of Fe 430 B metal substrates. • Methyl groups feature a very small steric hindrance and confer ductility to the Si–O–Si backbone. • Phenyl groups feature a larger steric hindrance, but they ensure stability and high chemical inertness. • Remarkable adhesion to the substrate, good scratch resistance and high wear endurance. • Innovative ways to design of long lasting protective barriers against corrosion and aggressive chemicals. - Abstract: Polysiloxanes are widely used as protective barriers to delay erosion/corrosion and increase chemical inertness of metal substrates. In the present work, a high molecular weight methyl phenyl polysiloxane resin was designed to manufacture a protective coating for Fe 430 B structural steel. Methyl groups feature very small steric hindrance and confer ductility to the Si–O–Si backbone of the organic inorganic hybrid resin, thus allowing the achievement of high thickness. Phenyl groups feature larger steric hindrance, but they ensure stability and high chemical inertness. Visual appearance and morphology of the coatings were studied by field emission scanning electron microscopy and contact gauge surface profilometry. Micro-mechanical response of the coatings was analyzed by instrumented progressive load scratch, while wear resistance by dry sliding linear reciprocating tribological tests. Lastly, chemical inertness and corrosion endurance of the coatings were evaluated by linear sweep voltammetry and chronoamperometry in aggressive acid environment. The resulting resins yielded protective materials, which feature remarkable adhesion to the substrate, good scratch resistance and high wear endurance, thus laying the foundations to manufacture long lasting protective barriers against corrosion and, more in general, against aggressive chemicals

Ceramic technology for advanced heat engines project. Semiannual progress report, April-September 1985

Energy Technology Data Exchange (ETDEWEB)

1986-05-01

An assessment of needs was completed, and a five-year project plan was developed with input from private industry. Objective is to develop the industrial technology base required for reliable ceramics for application in advanced automotive heat engines. Focus is on structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines. The work described in this report is organized according to the following WBS project elements: management and coordination; materials and processing (monolithics, ceramic composites, thermal and wear coatings, joining); materials design methodology (contact interfaces, new concepts); data base and life prediction (time-dependent behavior, environmental effects, fracture mechanics, NDE development); and technology transfer. This report includes contributions from all currently active project participants.

Improvement of Scratch and Wear Resistance of Polymers by Fillers Including Nanofillers

Directory of Open Access Journals (Sweden)

Witold Brostow

2017-03-01

Full Text Available Polymers have lower resistance to scratching and wear than metals. Liquid lubricants work well for metals but not for polymers nor for polymer-based composites (PBCs. We review approaches for improvement of tribological properties of polymers based on inclusion of fillers. The fillers can be metallic or ceramic—with obvious consequences for electrical resistivity of the composites. Distinctions between effectiveness of micro- versus nano-particles are analyzed. For example, aluminum nanoparticles as filler are more effective for property improvement than microparticles at the same overall volumetric concentration. Prevention of local agglomeration of filler particles is discussed along with a technique to verify the prevention.

Tribological properties of toughened zirconia-based ceramics

International Nuclear Information System (INIS)

Stachowiak, G.W.; Stachowiak, G.B.

1991-01-01

The physical and mechanical properties of toughened zirconia ceramics are briefly characterized and described with a special emphasis on their tribological behaviour. The wear and friction properties of PSZ and TZP ceramics at room and elevated temperatures are described. The influence of the environment on the tribological characteristics of zirconia ceramics is discussed. Both lubricated and unlubricated conditions for ceramic/ceramic and metal/ceramic sliding contacts are analysed. One of the main, and as yet unresolved problems, lubrication of ceramic at elevated temperatures and/or space environment, is addressed and the possible solutions to the problem are suggested. The critical needs in the research and development area of improving the tribological properties of zirconia ceramics are defined and its future market potentials stated. 30 refs., 2 tabs., 4 figs

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.

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

International Nuclear Information System (INIS)

Gusain, Rashi; Kokufu, Sho; Bakshi, Paramjeet S.; Utsunomiya, Toru; Ichii, Takashi; Sugimura, Hiroyuki; Khatri, Om P.

2016-01-01

Graphical abstract: - Highlights: • Ionic liquid thin film is deposited on a silicon surface via covalent interaction. • Chemical and morphological features of ionic liquid thin film are probed by XPS and AFM. • Ionic liquid thin film exhibited low and steady friction along with remarkable wear-resistivity. - Abstract: Imidazolium-hexafluorophosphate (ImPF_6) ionic liquid thin film is prepared on a silicon surface using 3-chloropropyltrimethoxysilane as a bifunctional chemical linker. XPS result revealed the covalent grafting of ImPF_6 thin film on a silicon surface. The atomic force microscopic images demonstrated that the ImPF_6 thin film is composed of nanoscopic pads/clusters with height of 3–7 nm. Microtribological properties in terms of coefficient of friction and wear-resistivity are probed at the mean Hertzian contact pressure of 0.35–0.6 GPa under the rotational sliding contact. The ImPF_6 thin film exhibited low and steady coefficient of friction (μ = 0.11) along with remarkable wear-resistivity to protect the underlying silicon substrate. The low shear strength of ImPF_6 thin film, the covalent interaction between ImPF_6 ionic liquid thin film and underlying silicon substrate, and its regular grafting collectively reduced the friction and improved the anti-wear property. The covalently grafted ionic liquid thin film further shows immense potential to expand the durability and lifetime of M/NEMS based devices with significant reduction of the friction.

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-02-28

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

Modeling and Investigation of the Wear Resistance of Salt Bath Nitrided Aisi 4140 via ANN

Science.gov (United States)

Ekinci, Şerafettin; Akdemir, Ahmet; Kahramanli, Humar

2013-05-01

Nitriding is usually used to improve the surface properties of steel materials. In this way, the wear resistance of steels is improved. We conducted a series of studies in order to investigate the microstructural, mechanical and tribological properties of salt bath nitrided AISI 4140 steel. The present study has two parts. For the first phase, the tribological behavior of the AISI 4140 steel which was nitrided in sulfinuz salt bath (SBN) was compared to the behavior of the same steel which was untreated. After surface characterization using metallography, microhardness and sliding wear tests were performed on a block-on-cylinder machine in which carbonized AISI 52100 steel discs were used as the counter face. For the examined AISI 4140 steel samples with and without surface treatment, the evolution of both the friction coefficient and of the wear behavior were determined under various loads, at different sliding velocities and a total sliding distance of 1000 m. The test results showed that wear resistance increased with the nitriding process, friction coefficient decreased due to the sulfur in salt bath and friction coefficient depended systematically on surface hardness. For the second part of this study, four artificial neural network (ANN) models were designed to predict the weight loss and friction coefficient of the nitrided and unnitrided AISI 4140 steel. Load, velocity and sliding distance were used as input. Back-propagation algorithm was chosen for training the ANN. Statistical measurements of R2, MAE and RMSE were employed to evaluate the success of the systems. The results showed that all the systems produced successful results.

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

Science.gov (United States)

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

2018-02-01

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

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

Directory of Open Access Journals (Sweden)

Estrada-Ruiz R.H.

2016-01-01

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

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.

The ceramic SiO2 and SiO2-TiO2 coatings on biomedical Ti6Al4VELI titanium alloy

International Nuclear Information System (INIS)

Surowska, B.; Walczak, M.; Bienias, J.

2004-01-01

The paper presents the study of intermediate SiO 2 and SiO 2 -TiO 2 sol-gel coatings and dental porcelain coatings on Ti6Al4VELI titanium alloy. Surface microstructures and wear behaviour by pin-on-disc method of the ceramic coatings were investigated. The analysis revealed: (1) a compact, homogeneous SiO 2 and SiO 2 -TiO 2 coating and (2) that intermediate coatings may provide a durable joint between metal and porcelain, and (3) that dental porcelain on SiO 2 and TiO 2 coatings shows high wear resistance. (author)

Erosion wear of boron carbide ceramic nozzles by abrasive air-jets

International Nuclear Information System (INIS)

Deng Jianxin

2005-01-01

Boron carbide nozzles were produced by hot pressing. The erosion wear of this nozzle caused by abrasive particle impact was investigated by abrasive air-jets. Silica, silicon carbide and alumina powders with different hardness were used as the erodent abrasive particles. Results showed that the hardness of the erodent particles played an important role with respect to the erosion wear of the boron carbide nozzles. As the hardness of the erodent particles increases, there is a dramatic increase in erosion rate of the nozzles. The nozzle entrance area suffered from severe abrasive impact under large impact angles, and generated maximum tensile stresses. The wear mechanisms of boron carbide nozzle at this area appeared to be entirely brittle in nature with the evidence of large scale-chipping, and exhibited a brittle fracture induced removal process. While at the nozzle center wall section, most of the particles traveled parallel to the nozzle wall, and showed minimum tensile stresses. The wear mode in this area of the nozzle changed from impact to sliding erosion, and the wear mechanisms appeared to be the lateral cracking owing to a surface fatigue fracture mechanism

Wear-resistance investigation of electro-screen coatings obtained using electroerosive powders of micro and nanofractions

Science.gov (United States)

Ageev, E. V.; Altukhov, A. Yu; Malneva, Yu V.; Novikov, A. N.

2018-03-01

The results of the wear resistance investigation of electro sparking coatings, applied using electrode material from electroerosive powders of hard alloy VK-8 (90%) with the addition of powder of high-speed steel of grade R6M5 (10%), are presented. Electro spark coatings were formed on samples of 30KhGSA steel using these electrodes and installation UR-121. The coefficient of friction and the wear rate of the surface of the sample and counterbody were measured on an automated friction machine “Tribometer” (CSM Instruments, Switzerland), controlled by a computer, according to the standard “ball-disk” test scheme.

Sputter deposition of wear-resistant coatings within the system Zr-B-N

Energy Technology Data Exchange (ETDEWEB)

Mitterer, C; Uebleis, A; Ebner, R [Inst. fuer Metallkunde und Werkstoffpruefung, Montanuniv., Leoben (Austria)

1991-07-07

Wear-resistant coatings of zirconium boride and zirconium boron nitride were deposited on steel and molybdenum substrates employing non-reactive as well as reactive d.c. magnetron sputtering using zirconium diboride targets. The characterization of the coatings was done by means of scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The results are discussed in connection with measured mechanical coating properties such as microhardness and adhesion. The optical properties of the coatings were determined using a CIE-L{sup *}a{sup *}b{sup *} colorimeter and specialized corrosion and abrasion tests. Non-reactive sputtering using ZrB{sub 2} targets results in the formation of coatings with a columnar structure and predominantly (001)-orientated ZrB{sub 2} crystals. Coatings deposited at low nitrogen flow rates exhibit very fine-grained or even fracture amorphous structures with a hexagonal Zr-B-N phase derived from the ZrB{sub 2} lattice. A further increase of the nitrogen flow leads to an amorphous film growth. The maximum Vickers microhardness of the coatings was found to be approximately 2300 HV 0.02. Zr-B and Zr-B-N coatings offer a wide range of interesting colours as well as good corrosion and wear resistance. (orig.).

Extensive Bone Reaction From Catastrophic Oxidized Zirconium Wear.

Science.gov (United States)

Cassar-Gheiti, Adrian J; Collins, Dennis; McCarthy, Tom

2016-01-01

The use of alternative bearing surfaces for total hip arthroplasty has become popular to minimize wear and increase longevity, especially in young patients. Oxidized zirconium (Oxinium; Smith & Nephew, Memphis, Tennessee) femoral heads were introduced in the past decade for use in total hip arthroplasty. The advantages of oxidized zirconium include less risk of fracture compared with traditional ceramic heads. This case report describes a patient with a history of bilateral avascular necrosis of the femoral head after chemotherapy for acute lymphoblastic leukemia. Nonoperative management of avascular necrosis failed, and the patient was treated with bilateral total hip arthroplasty. The patient was followed at regular intervals and had slow eccentric polyethylene wear during a 10-year period. After 10 years, the patient had accelerated wear, with femoral and acetabular bone changes as a result of Oxinium and ultrahigh-molecular-weight polyethylene wear during a 6-month period. This article highlights the unusual accelerated bone changes that occurred as a result of Oxinium wear particles. Copyright 2016, SLACK Incorporated.

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

Wear Resistance Increase by Friction Stir Processing for Partial Magnesium Replacement in Aluminium Alloys

Science.gov (United States)

Balos, Sebastian; Labus Zlatanovic, Danka; Janjatovic, Petar; Dramicanin, Miroslav; Rajnovic, Dragan; Sidjanin, Leposava

2018-03-01

In this paper, the influence of friction stir processing (FSP) was evaluated as a way of increasing mechanical properties and a way of replacing the magnesium content in aluminium alloys. FSP was done on AA5754 H111 aluminium alloy, containing 3 % Mg, by using various types of tools and different welding speeds, rotational speeds and tilt angles. Wear test was done against SiC abrasive papers. SiC was used to simulate extreme abrasive wear conditions. The wear test was done on untreated AA5754 specimens, processed AA5754 specimens and untreated AA5083 H111 specimens, the latter containing 4.5 % Mg. AA5083 was chosen as an alternative to AA5754, but with a significantly higher Mg content. Base material microhardness was 60 HV1 and 80 HV1 for AA5754 and AA5083 alloys respectively. To find the effect of FSP on AA5754 alloy, microstructures were studied, mainly grain size in the stir zone. It was found, that an elevated processing and rotational speed, without tilt angle and the tool without a reservoir resulted in an increase in hardness of the AA5754 to 70 HV1, but with the occurrence of tunneling defect and the wear rate of 79.3 mg. Lower FSP parameters and a tilted tool with a reservoir resulted in microhardness of 68 HV1 and wear rate of 68.2 mg without tunneling. These wear values are lower than those obtained with unmodified Al-alloys: AA5754 97.2 mg and AA5083 86.3 mg. An increased wear resistance can be attributed to the combined effect of grain boundary strengthening mechanism and solid solution strengthening, versus only the latter in untreated alloys.

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

Science.gov (United States)

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

2017-08-01

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

Sliding Wear Behaviour and Corosion Resistance to Ringer’s Solution of Uncoated and DLC Coated X46Cr13 Steel

Directory of Open Access Journals (Sweden)

Scendo M.

2016-12-01

Full Text Available Sliding wear properties and corrosion resistance in Ringer’s solution of uncoated and diamond-like carbon (DLC coated X46Cr13 steel was tested. The Raman spectra showed that the DLC film was successfully coated by plasma assisted CVD method onto the steel surface. The wear test, carried out using a ball-on disk tribometer, revealed that the DLC coating show better resistance to sliding wear and lower friction coefficient against a 100Cr6 steel ball than five times softer X46Cr13 steel. The oxidation kinetic parameters were determined by means of both the gravimetric and electrochemical method. It was found that the DLC coating markedly decreased the rate of corrosion of the X46Cr13 steel, irrespective of the corrosion mechanism involved.

Experimental studies of resistance fretting-wear of fuel rods for VVER-1000 and TVS-KVADRAT fuel assemblies

International Nuclear Information System (INIS)

Makarov, V.; Afanasiev, A.; Egorov, Yu.; Matvienko, I.

2015-01-01

The paper covers the results of the studies performed to justify the wear resistance of fuel rods in contact with the spacer grids of TVS VVER-1000 fuel assembly and TVS-KVADRAT square fuel assembly of Russian design for PWR-900 reactor. The presented results of three testing stages comprise: Testing of mockup fuel rods of VVER TVS fuel assembly for fretting wear under the conditions of the water chemistry of VVER reactor; Testing models of different design embodiments of the fuel rods for VVER TVS fuel assembly for fretting wear in still cold water; Testing mockup fuel rods of TVS-KVADRAT square fuel assembly for PWR reactor for frettingwear under the conditions of PWR water chemistry. The effect of structural and operational factors was determined (amplitudes, fuel rod vibration frequencies, values of cladding-to-spacer grid cell gap for the depth of fuel rod cladding wear etc.), an assessment was made of the threshold values of fuel rod vibration parameters, which, if not exceeded, provide the absence of the fuel rod cladding fretting wear in the fuel rod-to spacer grid contact area. Key words: fretting wear, fuel rod, spacer grid, VVER, PWR (author)

Bioactive glass-ceramic coating for enhancing the in vitro corrosion resistance of biodegradable Mg alloy

Science.gov (United States)

Ye, Xinyu; Cai, Shu; Dou, Ying; Xu, Guohua; Huang, Kai; Ren, Mengguo; Wang, Xuexin

2012-10-01

In this work, a bioactive 45S5 glass-ceramic coating was synthesized on magnesium (Mg) alloy substrate by using a sol-gel dip-coating method, to improve the initial corrosion resistance of AZ31 Mg alloy. The surface morphology and phase composition of the glass-ceramic coating were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The coating composed of amorphous phase and crystalline phase Na2Ca2Si3O9, with the thickness of ∼1.0 μm, exhibited a uniform and crack-free surface morphology. The corrosion behavior of the uncoated and coated Mg alloy substrates was investigated by the electrochemical measurements and immersion tests in simulated body fluid (SBF). Potentiodynamic polarization tests recorded an increase of potential (Ecorr) form -1.60 V to -1.48 V, and a reduction of corrosion current density (icorr) from 4.48 μA cm-2 to 0.16 μA cm-2, due to the protection provided by the glass-ceramic coating. Immersion tests also showed the markedly improved corrosion resistance of the coated sample over the immersion period of 7 days. Moreover, after 14 days of immersion in SBF, the corrosion resistance of the coated sample declined due to the cracking of the glass-ceramic coating, which was confirmed by electrochemical impedance spectroscopy (EIS) analysis. The results suggested that the 45S5 glass-ceramic coated Mg alloy could provide a suitable corrosion behavior for use as degradable implants.

"A New Class of Creep Resistant Oxide/Oxide Ceramic Matrix Composites"

Energy Technology Data Exchange (ETDEWEB)

Dr. Mohit Jain, Dr. Ganesh Skandan, Prof. Roger Cannon, Rutgers University

2007-03-30

Despite recent progress in the development of SiC-SiC ceramic matrix composites (CMCs), their application in industrial gas turbines for distributed energy (DE) systems has been limited. The poor oxidation resistance of the non-oxide ceramics warrants the use of envrionmental barrier coatings (EBCs), which in turn lead to issues pertaining to life expectancy of the coatings. On the other hand, oxide/oxide CMCs are potential replacements, but their use has been limited until now due to the poor creep resistance at high temperatures, particularly above 1200 oC: the lack of a creep resistant matrix has been a major limiting factor. Using yttrium aluminum garnet (YAG) as the matrix material system, we have advanced the state-of-the-art in oxide/oxide CMCs by introducing innovations in both the structure and composition of the matrix material, thereby leading to high temperature matrix creep properties not achieved until now. An array of YAG-based powders with a unique set of particle characteristics were produced in-house and sintered to full density and compressive creep data was obtained. Aided in part by the composition and the microstructure, the creep rates were found to be two orders of magnitude smaller than the most creep resistant oxide fiber available commercially. Even after accounting for porosity and a smaller matrix grain size in a practical CMC component, the YAG-based matrix material was found to creep slower than the most creep resistant oxide fiber available commercially.

FY 1997 report on the study on development of corrosion-resistant ceramics for refuse incinerators; 1997 nendo chosa hokokusho (gomi shokyakuroyo taishoku ceramics zairyo no kaihatsu ni kansuru kenkyu)

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

This paper describes development of structural materials for municipal refuse incinerators, in particular, high- temperature corrosion-resistant ceramics for inner walls. Unlike boiler tubes of which inner walls are cooled by water or water vapor, refractory for inner walls is subjected to high-temperature flame over 1000degC, corrosive gases such as HCl and SO2. and low-melting point corrosive dust such as chloride, sulfate and oxide under strong corrosive environment. Experiment was made on 14 kinds of ceramics including commercially available oxide system, non-oxide system and refractory system ceramics. Except graphite system ones, every ceramics, in particular, Al2O3, ZrO2, B4C-doped SiC and CVD-SiO showed superior properties. Commercially available ceramics, in particular, non-oxide system ones are very expensive. Since inner wall materials for refuse incinerators are heat-/corrosion-resistant consumption articles, it is suggested that improvement of reasonable oxide system ceramics or conventional SiC system ones is better. 73 refs., 89 figs., 39 tabs.

FIBROUS MONOLITH WEAR RESISTANT COMPONENTS FOR THE MINING INDUSTRY; SEMIANNUAL

International Nuclear Information System (INIS)

Mark J. Rigali; Kenneth L. Knittel; Mike L. Fulcher

2002-01-01

During this reporting period, work continued on development of formulations using the materials identified as contenders for the fibrous monolith wear resistant components. The FM structures fabricated were: diamond/WC-Co, B(sub 4)C/WC-Co, TiB(sub 2)/WC-Co, WC-Co/Co, WC-Co/WC-Co. Results of our consolidation densification studies on these systems lead to the down-selection of WC-Co/WC-Co, WC-Co/Co and diamond/WC-Co for further development for mining applications including drill bit inserts, roof bit inserts, radial tools conical tools and wear plates (WC-Co based system only) for earth moving equipment. Prototype component fabrication focused on the fabrication of WC-Co/WC-Co FM conical tools, diamond/WC-Co coated drill bit insert prototypes. Fabrication of WC-Co/WC-Co FM insert prototypes for a grader blade is also underway. ACR plans to initiate field-testing of the drill bit insert prototypes and the grader blade insert this summer (2002). The first WC-Co/WC-Co FM conical tool prototypes were sent to Kennametal for evaluation towards the end of the current reporting period

Insulating Structural Ceramics Program, Final Report

Energy Technology Data Exchange (ETDEWEB)

Andrews, Mark J.; Tandon, Raj; Ott, Eric; Hind, Abi Akar; Long, Mike; Jensen, Robert; Wheat, Leonard; Cusac, Dave; Lin, H. T.; Wereszczak, Andrew A.; Ferber, Mattison K.; Lee, Sun Kun; Yoon, Hyung K.; Moreti, James; Park, Paul; Rockwood, Jill; Boyer, Carrie; Ragle, Christie; Balmer-Millar, Marilou; Aardahl, Chris; Habeger, Craig; Rappe, Ken; Tran, Diana; Koshkarian, Kent; Readey, Michael

2005-11-22

New materials and corresponding manufacturing processes are likely candidates for diesel engine components as society and customers demand lower emission engines without sacrificing power and fuel efficiency. Strategies for improving thermal efficiency directly compete with methodologies for reducing emissions, and so the technical challenge becomes an optimization of controlling parameters to achieve both goals. Approaches being considered to increase overall thermal efficiency are to insulate certain diesel engine components in the combustion chamber, thereby increasing the brake mean effective pressure ratings (BMEP). Achieving higher BMEP rating by insulating the combustion chamber, in turn, requires advances in material technologies for engine components such as pistons, port liners, valves, and cylinder heads. A series of characterization tests were performed to establish the material properties of ceramic powder. Mechanical chacterizations were also obtained from the selected materials as a function of temperature utilizing ASTM standards: fast fracture strength, fatique resistance, corrosion resistance, thermal shock, and fracture toughness. All ceramic materials examined showed excellent wear properties and resistance to the corrosive diesel engine environments. The study concluded that the ceramics examined did not meet all of the cylinder head insert structural design requirements. Therefore we do not recommend at this time their use for this application. The potential for increased stresses and temperatures in the hot section of the diesel engine combined with the highly corrosive combustion products and residues has driven the need for expanded materials capability for hot section engine components. Corrosion and strength requirements necessitate the examination of more advanced high temperture alloys. Alloy developments and the understanding of processing, structure, and properties of supperalloy materials have been driven, in large part, by the gas

Gloss and Stain Resistance of Ceramic-Polymer CAD/CAM Restorative Blocks.

Science.gov (United States)

Lawson, Nathaniel C; Burgess, John O

2016-03-01

To evaluate the gloss and stain resistance of several new ceramic-polymer CAD/CAM blocks Specimens (4 mm) were sectioned from: Enamic (polymer-infused ceramic), LAVA Ultimate (nano-ceramic reinforced polymer), e.max (lithium disilicate), Paradigm C (porcelain), and Paradigm MZ100 (composite). Specimens were wet polished on a polishing wheel to either 320 grit silicon paper (un-polished, N = 8) or 2000 grit silicon carbide papers followed by a 0.05 μm alumina slurry (polished, N = 8). Initial gloss and color (L*a*b*) values were measured. Specimens were stored in a staining solution at 37°C in darkness for 12 days (simulating 1 year). After storage, L*a*b* values re-measured. Change in color was reported as ΔE00 based on the CIEDE2000 formula. Gloss and ΔE00 were analyzed by two-way analysis of variance (ANOVA) (alpha = .05). Separate one-way ANOVA and Tukey post-hoc analyses were performed for both polish conditions and all materials. Two-way ANOVA showed that factors material, polish and their interaction were significant for both gloss and ΔE00 (p gloss and less color change than all other materials. The composition and polish of CAD/CAM materials affects gloss and stain resistance. Ceramic-polymer hybrid materials can achieve the high gloss required for esthetic restorations. These materials should be polished in order to minimize staining. If polished, all of the tested materials exhibited clinically acceptable color changes at 1 year of simulated staining. (J Esthet Restor Dent 28:S40-S45, 2016). © 2015 Wiley Periodicals, Inc.

Tribological Behaviour of the Ceramic Coating Formed on Magnesium Alloy

International Nuclear Information System (INIS)

Chen Fei; Zhou Hai; Chen Qiang; Ge Yuanjing; Lv Fanxiu

2007-01-01

Micro-arc oxidation is a recently developed surface treatment technology under anodic oxidation. Through micro-arc oxidation, a ceramic coating is directly formed on the surface of magnesium alloy, by which its surface property is significantly improved. In this paper, a dense ceramic oxide coating was prepared on an AZ31 magnesium alloy by micro-arc oxidation in a NaOH-Na 2 SiO 3 -NaB 4 O 7 -(NaPO 3 ) 6 electrolytic solution. Micro-structure, surface morphology and phase composition were analysed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The tribological behavior of the micro-arc oxidation ceramic coating under dry sliding against GCr15 steel was evaluated on a ball-on-disc test rig. The results showed that the AZ31 alloy was characterized by adhesion wear and scuffing under dry sliding against the steel, while the surface micro-arc oxidation ceramic coating experienced much abated adhesion wear and scuffing under the same testing conditions. The micro-arc oxidation ceramic coating showed good friction-reducing and fair antiwear ability in dry sliding against the steel

Corrosion penetration monitoring of advanced ceramics in hot aqueous fluids

Directory of Open Access Journals (Sweden)

Klaus G. Nickel

2004-03-01

Full Text Available Advanced ceramics are considered as components in energy related systems, because they are known to be strong, wear and corrosion resistant in many environments, even at temperatures well exceeding 1000 °C. However, the presence of additives or impurities in important ceramics, for example those based on Silicon Nitride (Si3N4 or Al2O3 makes them vulnerable to the corrosion by hot aqueous fluids. The temperatures in this type of corrosion range from several tens of centigrade to hydrothermal conditions above 100 °C. The corrosion processes in such media depend on both pH and temperature and include often partial leaching of the ceramics, which cannot be monitored easily by classical gravimetric or electrochemical methods. Successful corrosion penetration depth monitoring by polarized reflected light optical microscopy (color changes, Micro Raman Spectroscopy (luminescence changes and SEM (porosity changes will be outlined. The corrosion process and its kinetics are monitored best by microanalysis of cross sections, Raman spectroscopy and eluate chemistry changes in addition to mass changes. Direct cross-calibrations between corrosion penetration and mechanical strength is only possible for severe corrosion. The methods outlined should be applicable to any ceramics corrosion process with partial leaching by fluids, melts or slags.

Experimental research on microhardness and wear resistances of pure Cu subjected to surface dynamic plastic deformation by ultrasonic impact

Science.gov (United States)

Chen, Zhaoxia; He, Yangming

2018-04-01

Dynamic plastic deformation (DPD) has been induced in the surface of pure Cu by ultrasonic impact treating (UIT) with the varied impact current and coverage percentage. The microstructures of the treated surface were analyzed by a scanning electron microscope (SEM). And the wear resistance of pure Cu was experimentally researched both with the treated and untreated specimens. The effect of DPD on the hardness was also investigated using microhardness tester. The results show that the grains on the top surfaces of pure Cu are highly refined. The maximum depth of the plastic deformation layer is approximately 1400 µm. The larger the current and coverage percentage, the greater of the microhardness and wear resistance the treated surface layer of pure Cu will be. When the impact current is 2 A and coverage percentage is 300%, the microhardness and wear resistance of the treated sample is about 276.1% and 68.8% higher than that of the untreated specimen, respectively. But the properties of the treated sample deteriorate when the UIT current is 3 A and the coverage percentage is 300% because of the formation of a new phase forms in the treated surface.

Research and development of the industrial basic technologies of the next generation, 'composite materials (fine ceramics)'. Evaluation of the first phase research and development; Jisedai sangyo kiban gijutsu kenkyu kaihatsu 'fine ceramics'. Daiikki kenkyu kaihatsu hyoka

Energy Technology Data Exchange (ETDEWEB)

NONE

1984-03-30

The results of the first phase research and development project for developing fine ceramics as the basic technologies of the next generation are evaluated. The R and D themes are selected to develop fine ceramics of high strength, corrosion resistance, precision and wear resistance, noting their excellent characteristics. Development of the basic techniques for these materials is of high significance, and highly rated. The efforts in the first-phase R and D project are aimed at development of silicon nitride and silicon carbide for synthesis of the stock materials; explosive forming/treating the stock powders; forming, sintering and processing/joining; evaluation of the characteristics; non-destructive testing methods; designs; and evaluation of the parts, among others, as the elementary techniques for production, evaluation and application of the fine ceramic materials. The technical targets of improving functions have been achieved, or bright prospects have been obtained therefor in development of the techniques for synthesis of the stock materials, forming/sintering and processing/joining. The silica reduction for stock synthesis, basic techniques for molding/sintering, and rheological considerations for the molding/sintering techniques represent the techniques of the next generation, because they break through the limitations of the conventional techniques. (NEDO)

Prediction of wear rates in comminution equipment

DEFF Research Database (Denmark)

Jensen, Lucas Roald Dörig; Fundal, Erling; Møller, Per

2010-01-01

-resistant high chromium white cast iron (21988/JN/HBW555XCr21), a heat-treated wear resistant steel (Hardox 400) and a plain carbon construction steel (S235). Quartz, which accounts for the largest wear loss in the cement industry, was chosen as abrasive. Other process parameters such as velocity (1–7 m...

Wear of ultra-high molecular weight polyethylene against damaged and undamaged stainless steel and diamond-like carbon-coated counterfaces.

Science.gov (United States)

Firkins, P; Hailey, J L; Fisher, J; Lettington, A H; Butter, R

1998-10-01

The wear of ultra-high molecular weight polyethylene (UHMWPE) in artificial joints and the resulting wear debris-induced osteolysis remains a major clinical concern in the orthopaedic sector. Third-body damage of metallic femoral heads is often cited as a cause of accelerated polyethylene wear, and the use of ceramic femoral heads in the hip is gaining increasing favour. In the knee prostheses and for smaller diameter femoral heads, the application of hard surface coatings, such as diamond-like carbon, is receiving considerable attention. However, to date, there has been little or no investigation of the tribology of these coatings in simulated biological environments. In this study, diamond-like carbon (DLC) has been compared to stainless steel in its undamaged form and following simulated third-body damage. The wear of UHMWPE was found to be similar when sliding against undamaged DLC and stainless steel counterfaces. DLC was found to be much more damage resistant than DLC. Under test conditions that simulate third-body damage to the femoral head, the wear of UHMWPE was seven times lower against DLC than against stainless steel (P < 0.05). The study shows DLC has considerable potential as a femoral bearing surface in artificial joints.

Influence of Plasma Transferred Arc Process Parameters on Structure and Mechanical Properties of Wear Resistive NiCrBSi-WC/Co Coatings

Directory of Open Access Journals (Sweden)

Eitvydas GRUZDYS

2011-07-01

Full Text Available Self-fluxing NiCrBSi and related coatings received considerable interest due to their good wear as well as corrosion resistance at moderate and elevated temperatures. Hard tungsten carbide (WC particles can be included in NiCrBSi for further increase of the coating hardness and abrasive wear resistance. Flame spray technique is widely used for fabrication of NiCrBSi films. However, in such a case, subsequent remelting of the deposited coatings by flame, arc discharge or high power laser beam is necessary. In present study NiCrBSi-WC/Co coatings were formed using plasma transferred arc process. By adjusting plasma parameters, such as current, plasma gas flow, shielding gas flow, a number of coatings were formed on steel substrates. Structure of the coatings was investigated using X-ray diffractometry. Microstructure of cross-sectioned coatings was examined using scanning electron microscopy. Hardness of the coating was evaluated by means of the Vickers hardness tests. Wear tests were also performed on specimens to determine resistance to abrasive wear. Acquired results allowed estimating the influence of the deposition process parameters on structure and mechanical properties of the coatings.http://dx.doi.org/10.5755/j01.ms.17.2.482

Tool life and surface roughness of ceramic cutting tool when turning AISI D2 tool steel