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Friction and wear of 13 different materials with silicon nitride (Si 3 N 4 ) matrix were investigated under unlubricated conditions. Tests were performed in laboratory air at sliding velocities between 0.03 and 5 m s -1 and at temperatures in the range of 22 to 1000 o C. These materials were tested in the same test rig by means of the pin-on-disc configuration...
An almost constant fracture toughness exists for the ceramic silicon nitride over a broad range of operating temperatures. However, Si 3 N 4 specimens show significant wear rate increases as the operating temperature is increased. It is therefore impractical to use fracture toughness to express the wear rates within the temperature range of 25°C to 550°C. However, notable changes in...
The fretting wear behaviour of silicon nitride against silicon nitride was investigated under lubricated conditions as a function of fretting amplitude and duration. Amplitudes in the intermediate 5–50 μm range and test durations from 10 to 360 min were studied, using the commercial lubricant ISO VG 220. Light microscopy, scanning electron microscopy, transmission electron microscopy and energy dispersive...
The combination of indentation, inclined-plane sliding, and wear tests provides useful and unique way to investigate ceramic wear and wear transition mechanisms. The experimental results show that wear mechanisms of ceramics are predominantly dependent on the tribological contact stresses. At low contact stress, the removal of material is controlled by plastic deformation induced microfracture on...
A ball-on-three-disc modification of the four-ball wear tester was utilized to evaluate the wear property of Si 3 N 4 lubricated with mineral oil, containing additives such as oleic acid, stearic acid and zinc dialkyldithiophosphate (ZDP). For comparison, the wear of a steel ball on Si 3 N 4 discs and an Si 3 N 4 ball on Si 3 N 4 discs...
The abrasive wear of brittle materials, while not a true property of materials, is generally modeled as an inverse function of both the bulk hardness and fracture toughness. According to these models, an increase in the hardness and/or fracture toughness of a material will therefore enhance its wear resistance. In ceramic materials, the addition of whisker reinforcement is a proven method of enhancing...
The relationship between two significantly different surface grinding conditions and the reciprocating ball-on-flat friction and wear behavior of a high-quality, structural silicon nitride material (GS-44) was investigated. The slider materials were silicon nitride NBD 200 and 440C stainless steel. Two machining conditions were selected based on extensive machining and flexural strength test data...
Molybdenum disilicide (MoSi 2 ) particles have been added to silicon nitride (Si 3 N 4 ) to form ceramic matrix-intermetallic composites. Benefits associated with the addition of the MoSi 2 to Si 3 N 4 include higher strength, higher fracture toughness, no loss in oxidation resistance, and lower electrical resistivity. However, since the hardness of...
This paper describes the effect of grain boundary chemistry, which can be easily altered by the amount of introduced sintering additives or impurities, on the high-temperature wear behavior of silicon nitride. Two different kinds of silicon nitride were made to investigate the effect of minor additives on the high-temperature wear behavior. A small amount of either CaO or Fe 2 O 3 ...
The results of studies on the influence of the amount of material removed from the surface of silicon nitride ball produced using the hot isostatic pressing (HIP) technique on the compressive residual stress are presented and discussed. They indicate that the residual compressive stress decreases as the amount of material removed grows. Initially, the rate of stress decrease is quite high but it decays...
Austenitic stainless steel AISI 321 is one of the most difficult to cut materials. In order to investigate the wear behavior of Si 3 N 4 ceramic when cutting stainless steel, wear tests were carried out using a pin-on-disk tribometer which could simulate a real cutting process. Test results show that the wear of Si 3 N 4 ceramic is caused mainly by adhesion between...
A tribofilm was formed during wear tests of a Si 3 N 4 -gray iron pair lubricated with distilled water. In order to clarify the formation process of the film, wear tests of the Si 3 N 4 -gray iron pair with different sliding distances were carried out on a ring-block tester using distilled water as lubricant. After the tests, the worn surfaces of the gray iron specimens...
The wear and friction behaviour of silicon nitride against bearing steel was investigated under lubricated and dry fretting conditions as a function of amplitude and test duration. Tests were performed on a high frequency fretting tester. Silicon nitride bearing balls were used as the upper oscillating specimens while the lower stationary flats were standard specimens of bearing steel. Amplitudes...
Wear of steel (AISI M-50 and AISI 52100) bearing balls in lubricated rolling contact with ground and ground-and-lapped silicon nitride rods was studied using a ball-on-rod rolling-contact-fatigue (RCF) tester. The steel balls suffered significant wear in rolling contact with the as-ground (R a = 0.18 μm) silicon nitride rods. The wear volume loss was approximately linear with the rolling distance...
As the loosening of a hip joint is caused by the tissue response to polyethylene wear particles, ceramic-ceramic joints are needed for long-term or permanent replacements. We have compared the start up and steady state friction of four ceramic materials against themselves lubricated with 1 wt.% water solution of carboxymethyl cellulose sodium salt (CMC-Na 1 wt.% water solution). The experimental results...
Using distilled water and air lubricants, wear tests of ceramic-cast iron pairs were carried out on a M-200 type ring-block wear tester. For comparison, ceramic-carbon steel pairs were also tested under the same conditions. The worn surfaces of specimens were observed under scanning electron microscope (SEM) and optical microscope. Furthermore, the tribofilms were analyzed by using Auger electron...
Magnetic float polishing (MFP) technique is used in the finishing of advanced ceramics, namely, silicon nitride (S 3 N 4 ) balls for hybrid bearing applications. In this paper, Taguchi method [Genichi Taguchi, Taguchi Methods—Research and Development, ASI Press, Dearborn, MI (1992); K.E. Dehnad, Quality Control, Robust Design, and the Taguchi Method, Brooks/Cole, CA (1989)] is applied...
The wear property of Si 3 N 4 under vapor phase lubrication of oleic acid and tricresyl phosphate (TCP) in both steel-on-Si 3 N 4 and Si 3 N 4 -on-Si 3 N 4 systems were investigated. The used oleic acid and TCP were fed into the evaporator simultaneously with two syringe pumps, and the vaporized lubricants were delivered by the carrier...
The conventional method of producing of Si 3 N 4 balls for bearing applications by grinding and lapping using diamond abrasive at low speeds ( < a few hundred rpm) and higher loads (several tens of N/ball) is generally an expensive and time-consuming operation (several weeks). It also leads to the formation of scratches, microcracks, and pits on the finished balls resulting from...
This study addresses the influence of grinding-induced roughness, subsurface damage and residual stress on the repeated impact behavior of silicon nitride, a leading material for diesel poppet-valves. A ball-on-flat repeated impact tester was used to evaluate the impact wear of GS-44 silicon nitride coupons machined in three different conditions: coarsely ground (with 80-grit wheel), finely ground...
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