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Ti_3SiC_2和Si_3N_4等陶瓷材料是一种潜在的生物燃料发动机及功能性运动部件材料,为研究其在醇类生物燃料及润滑剂中的摩擦学性能,利用往复式摩擦试验机研究Ti_3SiC_2/Si_3N_4摩擦副在不同碳原子数直链醇(乙醇、丁醇、辛醇和十二醇)和不同羟基数醇(乙二醇和丙三醇)液体介质中的摩擦学性能。结果表明:Ti_3SiC_2/Si_3N_4在醇介质中的摩擦因数随碳原子数和羟基数的增加而减小,总体平均摩擦因数在0.06~0.11范围内变化,但丁醇中摩擦因数最高,为0.25;Ti_3SiC_2/Si_3N_4配副的磨损率均随碳原子数和羟基数的增加而减小,Ti_3SiC_2的磨损率在4.48×10~(-7)~9.33×10~(-9) mm~3/(N·m)范围内变化,Si_3N_4的磨损率在4.05×10~(-6)~2.91×10~(-7)mm~3/(N·m)之间变化,其中在辛醇和十二醇中几乎没有磨损。研究表明:在醇介质中Ti_3SiC_2/Si_3N_4摩擦副的摩擦状态属于边界润滑状态,摩擦界面微凸体和磨屑的犁沟效应是造成高摩擦的主要原因;摩擦化学反应是Ti_3SiC_2/Si_3N_4在醇介质中的摩擦行为的一个特点,摩擦化学磨损和磨粒磨损是材料磨损的主要机制;链长越长、羟基越多,醇的黏度越大,承载能力越强,犁沟效应和磨粒磨损降低,摩擦因数和磨损率也降低。 相似文献
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In the present paper, friction and wear behaviors of a carbon fiber reinforced carbon–silicon carbide–titanium silicon carbide (C-SiC–Ti3SiC2) hybrid matrix composites fabricated by slurry infiltration and liquid silicon infiltration were studied for potential application as brake materials. The properties were compared with those of C/C-SiC composites. The composites containing Ti3SiC2 had not only higher friction stability coefficient but also much higher wear resistance than C/C-SiC composites. At an initial braking speed of 28 m/s under 0.8 MPa pressure, the weight wear rate of the composites containing 5 vol% Ti3SiC2 was 5.55 mg/cycle, which was only one-third of C/C-SiC composites. Self-lubricious film-like debris was formed on the composites containing Ti3SiC2, leading to the improvement of friction and wear properties. The effect of braking speed and braking pressure on the tribological properties of modified composites were investigated. The average friction coefficient was significantly affected by braking speed and braking pressure, but the wear rate was less affected by braking pressure. 相似文献
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《Wear》2007,262(5-6):529-535
Micro- and nano-sized hot-pressed silicon carbide pins have been characterized by room-temperature unlubricated disk-on-pin tribological tests on hot-pressed silicon carbide and silicon nitride discs. The mean grain size was shown not to influence the steady state friction coefficient. The mean grain size clearly affected the disc wear rate: the finer was the grain size the lower was the disc wear rate. No impact of the grain size was observed on the pin wear rate. The basic wear mechanisms were grain fracture and fine abrasion. By depth-sensing indentation, it was shown that a possible explanation of the different wear behaviour between micro- and nano-sized silicon carbide are the values of mechanical properties, especially hardness, when they are measured on volumes scaling with the material microstructure. 相似文献
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研究了由热等静压原位合成的Ti3SiC2/SiC复相陶瓷与45#钢在干摩擦和边界油润滑条件下的摩擦磨损特性.结果表明:干摩擦条件下随载荷的变化,占主导地位的磨损机制将发生变化,在低载荷下以磨粒磨损为主,高载荷下以粘着磨损为主;同干摩擦相比,润滑油对摩擦副的摩擦磨损性能的改善均很显著;Ti3SiC2/SiC复相陶瓷的磨损主要由粘着和微断裂引起的. 相似文献
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Under certain conditions, silicon nitride and silicon carbide ceramics can be lubricated by water; however, silicon carbide generally takes 5-6 times longer to enter the effective tribochemical regime than silicon nitride. Despite this, the operating range for silicon carbide is much larger once it enters into this regime. This paper examines the various explanations for why these two ceramics should exhibit different time constants for tribochemistry to occur. Using a ball-on-three-flat bench wear test in water, a preworn-in procedure was used to control surface roughness and tribochemical induction times were measured. It was found that wear-particle-induced third body effect prevented the successful entrance into the tribochemical regime for silicon carbide. It was postulated that the films formed are very susceptible to third body effect and require smooth surfaces for the tribochemical reaction films to be effective. 相似文献
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The fretting wear behaviour of bearing steel against bearing steel, silicon nitride against silicon nitride, and silicon nitride against bearing steel, was investigated under lubricated and dry conditions. Amplitudes in the intermediate 5 to 50 μm range, and test durations from 10 to 360 min, were studied. Light microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) were employed to determine the detailed nature of the friction and wear processes. In the silicon nitride against silicon nitride contact, brittle fracture of Si3N4 grains, and tribochemical reaction creating an amorphous layer on the mechanically damaged surface, were found. The main mechanism of fretting wear in the case of bearing steel against bearing steel contact was delamination. In the silicon nitride against bearing steel contact, chemical reactions predominated. 相似文献
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热压Si3N4/MoSi2复合材料的强韧化效果与机制 总被引:3,自引:0,他引:3
通过显微组织观察和力学性能测试,对亚微米Si3N4颗粒强韧化MoSi2的效果及其作用机制进行了初步研究和探讨.结果表明:复合材料中的Si3N4颗粒在基体的间层作用,可抑制MoSi2晶粒长大;断口呈现晶粒细小、裂纹扩展曲折和沿晶与穿晶混合型断裂等特征;Si3N4颗粒通过弥散强化和细化晶粒使复合材料强度提高,室温断裂韧度达到8.2 MPa·m1/2,通过晶粒细化、裂纹偏转和分支、微裂纹形成等机制的综合作用使复合材料增韧. 相似文献
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Si3N4/MoSi2陶瓷的制备工艺与组织研究 总被引:3,自引:1,他引:3
研究了Si3N4/MoSi2复合陶瓷材料的特殊制备工艺及其显微结构的变化。用XRD、SEM、EDXS及气孔率测试仪,对每一制备步骤中发生的显微结构变化进行了分析。 相似文献
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In this study, an effort was made to control the friction and wear behavior of silicon carbide (SiC) and silicon nitride (Si3N4) ceramics using an ultrasonic nanocrystalline surface modification (UNSM) technique. The friction and wear behavior of the ceramic specimens was investigated using a ball-on-disk tribotester under dry conditions against two different Si3N4 and bearing steel (SUJ2) balls. The experimental test results revealed the possibility of controlling the friction and wear behavior of ceramics, where the friction coefficient and wear resistance of the specimens were improved by the UNSM technique. The hardness of the specimens also increased after UNSM treatment, but it decreased abruptly with increasing depth from the very top surface. Microscratch tests showed that the critical load of the specimens was improved by the UNSM technique. In addition, Raman spectra results revealed that no additional phase was detected after UNSM treatment, but the intensity decreased after UNSM treatment. Hence, the UNSM technique ensures stronger ceramics and enables better friction and wear behavior than available conventional sintered ceramics. 相似文献
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用 Mo粉、Si粉通过二步法反应制得 Si3N4/Mo Si2 复合材料 ,并用 X射线衍射和扫描电镜、抗折仪等方法对材料进行了显微结构和机械性能的测定。研究表明 ,复合材料的机械性能 ,特别是高温机械性能比 Si3N4材料有显著的提高 相似文献
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The Difference in Running-In Period and Friction Coefficient Between Self-Mated Si3N4 and SiC Under Water Lubrication 总被引:2,自引:0,他引:2
Running-in periods and friction coefficients of SiC and Si3N4 sliding against themselves under water lubrication were investigated with a pin-on-disk apparatus at sliding speed of 120 mm/s and a normal load of 5 N under ambient conditions. It was found that the running-in period of self-mated Si3N4 is much shorter than that of self-mated SiC, and also that the steady-state friction coefficient of self-mated Si3N4 was lower (0.0035) than that of self-mated SiC (0.01). The difference in mechanism was analyzed from the point of view of electronic structure and surface chemistry. 相似文献
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本文着重介绍利用AtomScan Advantage 电感耦合等离子体发射光谱仪分析高纯氢氧化钠中Fe_2O_3含量,并与传统分光先度法相比较,表明ICP-AES法在生产分析中的优越性。 相似文献
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采用双螺杆挤出机熔融共混和注射成型方法制备了PA66/Si3N4纳米复合材料.研究了纳米Si3N4添加量对复合材料的力学性能和摩擦磨损性能的影响.通过对试样磨损表面及其对摩副表面上转移膜的扫描电子显微镜(SEM)观察和X射线光电子能谱(XPS)分析,探讨了其磨损机制.结果表明,纳米Si3N4的加入降低了基体的拉伸强度和弯曲强度,但是在PA66中加入适量的纳米Si3N4颗粒后,摩擦过程中有利于生成较均匀的转移膜,从而降低摩擦因数.同时磨屑里的纳米Si3N4镶嵌到试样摩擦表面,使表面得到局部增强,从而提高其耐磨性能. 相似文献
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The tribological behavior of self-mated Ti3SiC2 in low viscosity fluids, that is, water and ethanol, is investigated. The results show that both water and ethanol effectively reduce the friction and wear of self-mated Ti3SiC2. The friction coefficient and total wear rates of Ti3SiC2 tribo-pair are 0.82 and 2.17 × 10?2 mm3/N m under dry condition, 0.41 and 6.50 × 10?4 mm3/N m in water and 0.16 and 2.22 × 10?4 mm3/N m in ethanol. As sliding distance is prolonged from 0.5 to 22.9 km, the total wear rates of Ti3SiC2 in ethanol can be further reduced. Mechanical wear of Ti3SiC2 is partly inhibited in water and greatly inhibited in ethanol. Surface polishing of Ti3SiC2 pin and tribochemistry are the two distinct characteristics of self-mated Ti3SiC2 in ethanol. The surface film in ethanol is composed of TiO2 and SiO. Tribo-products in ethanol, that is, silica gel and titanium dioxide, are found. Polycondensation of ethanol by the catalysis of TiO2 and SiO2?x gives birth to paraffins and olefins. 相似文献