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1.
针对纯水液压元件摩擦副实际工况,研究了水润滑状态下Al2O3和Al2O3 13%TiO2等离子喷涂试环分别与整体烧结Al2O3块之间的摩擦磨损特性,考察了摩擦系数及试环磨损量随时间的变化,利用扫描电子显微镜(SEM)观察了磨痕的表面形貌,利用X射线能量色散谱仪分析了磨痕表面的元素组成。研究结果表明:水润滑条件下两种摩擦副的磨损机理主要是脆性断裂、微切削与腐蚀磨损;摩擦副Al2O3环/整体烧结Al2O3块的摩擦学性能优于Al2O3 13%TiO2/Al2O3块,它们更适合作为纯水液压元件的摩擦副材料。 相似文献
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Dry frictional contact between two surfaces, one made of plasma sprayed ceramic coatings of Al2O3 and Al2O3---TiO2 combination and the other made of steel, is analyzed. The experiments were conducted using a pin-on-disc set-up in the load range of 5–35 N and for sliding distances up to 14 km. The interactions between friction, wear and vibrations due to influence of normal load, sliding speed and system dynamics are investigated in the present paper. Two vibration parameters of pin in the load direction (vertical) are monitored, namely the r.m.s. acceleration and the kurtosis, which seem to be influenced considerably by the wear process and indicate correlation with wear mechanisms taking place such as stick-slip and grain pull-out, as evidenced by scanning electron microscopy of worn surfaces. The study shows that a range of frequency is to be utilized for vibration monitoring to include natural frequencis of the system consisting of pin in contact with disc. This could be estimated by a standard impulse hammer test. The pin acceleration decreases with increase in load and sliding distance, but with respect to sliding speed, the vibration level intially decreases but increases beyond the sliding speed of 1.5 m s−1. Among the three ceramic coatings, TiO2 is found to be most wear resistant, exhibiting the lowest friction coefficient and a low vibration level. Variation in kurtosis with run-in wear indicates smoothing of Al2O3 due to grain pull out. 相似文献
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不同喷涂工艺制备的Al_2O_3-13%TiO_2涂层表面自由能与冲蚀磨损性能研究 总被引:3,自引:0,他引:3
采用接触角测量仪和冲蚀磨损试验机等设备,研究超声速等离子喷涂与普通大气等离子喷涂两种技术制备的Al_2O_3-13%TiO_2涂层的表面自由能和冲蚀磨损性能,并对涂层的显微硬度、孔隙率及成分进行检测分析。研究结果表明,普通大气等离子喷涂技术制备的涂层,其表面和内部结构疏松,孔隙率及显微硬度分别为6.653%和836.93 HV0.1。而超声速等离子喷涂技术制备的涂层,孔隙率及显微硬度分别为3.467%和1 078.68 HV0.1,相比普通大气等离子喷涂而言,超声速等离子喷涂制备的涂层整体性能较为优异。通过对两种涂层的结构和表面自由能分析发现,超声速等离子喷涂Al_2O_3-13%TiO_2涂层由于结构致密、表面自由能较低而具有较为出色的冲蚀磨损性能。 相似文献
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The tribological behaviour of oil‐lubricated steel‐alumina sliding pairs was investigated using a ball‐on‐disc tribometer at room temperature. Commercial bearing balls of 10 mm diameter were mated to 99.7% Al2O3 discs, and additive‐free mineral oil was fed into the contact area. The sliding speed and the applied normal load were varied, and the initial surface roughness of the Al2O3 disc was altered using different polishing and grinding procedures. The results showed that the surface roughness of the ceramic discs dominated the tribological behaviour under the given experimental conditions. The sliding speed as well as the normal load showed less effect on the friction behaviour, but the amount of wear depended strongly on the normal load. From the results it was concluded that improvement of the surface roughness and optimised surface machining of the ceramic material can be essential for improving the tribological performance for boundary‐lubricated steel‐ceramic sliding pairs. 相似文献
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Al2O3陶瓷阀芯耐磨性的研究 总被引:5,自引:1,他引:4
从陶瓷零件副的实际应用出发,采用失重法研究了Al2O3陶瓷的磨损情况,根据磨损结果,分析了陶瓷材料的磨损表面,磨损机理,表明陶瓷的磨损率较低,具有广阔的应用前景。 相似文献
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提出了700mm长Al_2O_3陶瓷导轨超精密加工的工艺流程;依次介绍了磨削、研磨使用的工艺方法和检测方法,并详细介绍了采用自行研发的超精密导轨研磨抛光机对导轨抛光的工艺方法、工艺参数和检测方法。采用Zygo平面干涉仪检测导轨面形,通过子孔径拼接技术,得到导轨面700mm×260mm表面面形误差最大峰谷值为0.78λt(λ=632.8nm),面形误差均方根值为0.1λ。 相似文献
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镍-磷-纳米Al2O3复合镀层的摩擦学性能 总被引:5,自引:1,他引:4
用化学镀的方法制备了镍-磷-纳米Al2O3复合镀层,研究了热处理温度对镀层硬度和磨损性能的影响,并与二元镍-磷镀层以及镍-磷-Al2O3复合镀层进行了性能对比。结果表明:含有纳米Al2O3微粒的复合镀层具有更高的硬度和耐磨性,经400℃处理后的镀层耐磨性最好。 相似文献
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The tribological properties of (Al2O3) ceramics/1Cr18Ni9Ti stainless steel rubbing pairs were investigated using a MMW‐1 tribo‐tester under pure water and different concentrations of hydrogen peroxide (H2O2) solutions. A comparison analysis of the friction coefficient, wear mass loss and worn surface topographies was conducted. The wear mass loss of the 1Cr18Ni9Ti stainless steel ring sample in all H2O2 solutions was greater than that in pure water. The wear mass loss was the highest in 70% H2O2 solution. The comprehensive analysis showed that the main wear mechanisms between the Al2O3 ceramics/1Cr18Ni9Ti stainless steel rubbing pairs were severe adhesive, abrasive and ploughing wear in the H2O2 solutions. It is believed that the knowledge gained in this study will provide the theoretical data and guide for the optimisation of the rubbing pairs in the H2O2 solutions to be used for the lubrication of some moving parts in the propulsion system of the launch vehicle. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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选用三种ZrO2含是不同的Al2O3-ZrO2热喷涂涂层与铸铁匹配,在不同润滑油润滑条件下进行高温实验研究,结果表明陶瓷涂层表面亦有较强的化学活性,Al2O2-ZrO2陶瓷涂层与矿物油有较好配伍性,高温摩擦条件下生成减以应膜。 相似文献
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Kirsten BOBZIN Lidong ZHAO Nils KOPP Thomas WARDA 《Frontiers of Mechanical Engineering》2012,7(4):371
Carbon fibre reinforced carbon (CFC) materials are increasingly applied as sample carriers in modern furnaces. Only their tendency to react with different metals at high temperatures by C-diffusion is a disadvantage, which can be solved by application of diffusion barriers. Within this study the feasibility of plasma sprayed Al2O3 coatings as diffusion barrier was studied. Al2O3 coatings were prepared by air plasma spraying (APS). The coatings were investigated in terms of their microstructure, bonding to CFC substrates and thermal stability. The results showed that Al2O3 could be well deposited onto CFC substrates. The coatings had a good bonding and thermal shock behavior at 1060°C. At higher temperature of 1270°C, crack network formed within the coating, showing that the plasma sprayed Al2O3 coatings are limited regarding to their application temperatures as diffusion barrier on CFC components. 相似文献
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纳米流体作为强化换热介质,是目前的研究热点,但关于其相变过程的研究较少。利用当量比热法,在COMSOL有限元模拟软件中对质量分数为5%,不同粒径(10、20、50、100、500nm)的Al2O3-H2O纳米流体和去离子水的冻结过程进行数值模拟,并将模拟结果和试验结果进行了对比。二者具有较好一致性,表明烧杯中心和壁面附近的温度变化趋势有较大区别,中心处的温度变化更能反映样品的冻结过程;当质量分数为5%时,Al2O3-H2O纳米流体的相变时间与去离子水相比较短,且纳米流体的相变时间随Al2O3粒径的增大而增加。 相似文献
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应用扫描电镜对纳米结构Al2O3/13TiO2(n-Al2O3/13TiO2)涂层精密磨削后的表面/亚表面形貌进行观察和分析,结合对n-Al2O3/13TiO2精密磨削的单颗磨粒磨削力、磨削力分力比和比磨削能的磨削实验结果的分析,揭示了n-Al2O3/13TiO2涂层精密磨削的材料去除机理.研究表明,在大多数磨削条件下,n-Al2O3/13TiO2陶瓷涂层磨削的材料去除机理主要是以材料碎裂和材料压碎等脆性去除方式为主,同时也存在一定的材料粉末化以及极少的显微塑性变形等方式.研究结论对纳米结构陶瓷涂层的工业化应用具有重要的理论和实用价值. 相似文献
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采用sol-gel法制备了w(Al2O3)为2%~4%的Al2O3-ZnO纳米粉体,利用XRD和SEM等测试手段分析了粉体的微观结构.研究了Zn2+浓度、pH值和清洗对粉体制备的影响.采用静态配气法测试了由所制粉体制成的气敏元件对丙酮、乙醇、甲醇等气体的气敏性能.结果表明:用该法得到的粉体材料颗粒粒径小,工作温度为160℃时,由w(Al2O3)为3%的粉体在700℃退火制得的气敏元件对体积分数为40%的丙酮的灵敏度最高可达到7 779,响应-恢复时间均为1S. 相似文献
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用粉末烧结法制备出了开孔型多孔铝及以Al2O3为增强相的铝基多孔复合材料,材料相对密度及孔径分别在0.25~0.40和100~400 μm范围内变化.对这两种多孔材料的压缩行为进行了研究.结果表明:Al/Al2O3复合材料有着比多孔铝更为有利的响应特征和更高的流动应力,该复合材料的压缩应力-应变曲线较为平坦,在与多孔铝相对密度相近时,屈服强度提高40%以上;经T6热处理,Al/Al2O3复合材料的屈服强度可进一步提高35%左右;此外,该复合材料的压缩行为具有明显的孔径依赖性,随孔径增大,流动应力升高,这主要与烧结过程中孔表面残留的气体有关. 相似文献
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Friction and wear behavior of ultra-high molecular weight polyethylene (UHMWPE) sliding against Al2O3 ceramic under dry sliding, and lubrication of fresh plasma, distilled water and physiological saline were investigated with a self-made pin-on-disk apparatus at 37±1°C. The worn surfaces were examined with a scanning electron microscope (SEM). The results show that the friction behavior of UHMWPE is very sensitive to its water absorption state. The wear rate of UHMWPE under dry sliding is the highest and under plasma lubrication is the lowest. The wear mechanisms are different under dry friction and various lubricating conditions. 相似文献
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Digital image analysis and point-pattern analysis were applied to the microstructures of Al2O3-ZrO2 composites in order to evaluate and classify the distribution of ZrO2 particles. Scanning electron microscopy micrographs of Al2O3-ZrO2 microstructures were digitized and processed into binary images. Point-pattern analysis was performed using data for mass centers for each ZrO2 particle and the calculated distribution functions were compared with defined point-pattern distributions—clustered, random, and ordered. Distribution functions for analyzed samples were classified into random groups with different degrees of homogeneity, arising due to the preparation routine. It was shown that the point-pattern analysis can be used to distinguish between the type of distribution and degree of homogeneity for Al2O3 ceramic composites. 相似文献
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Alumina/SiC nanocomposites were produced by mechanical mixture of commercial powders. The preparation steps involved the vigorous mixing of the powders and drying under conditions where the homogeneous mixture was kept stable. Pressureless sintering of die-pressed powders achieved reasonable densities (~97% theoretical density) for 2·5wt% of SiC on sintering at 2073 K. Higher SiC contents strongly reduced the sintered density. The use of a more reactive alumina (finer matrix powder) gave similar results. Hot pressing at 1973 K/1 h/25 MPa produced high-density materials for SiC contents as high as 20 wt%. Transmission and scanning electron microscopy analysis showed that the SiC particles were well distributed and were situated both inside the grains and on the grain boundaries of the alumina matrix. The SiC strongly inhibited grain growth in the matrix in keeping with the Zener model. The bend strength increased as the SiC content increased, a result partly explained by the grain size refinement. The strength improvement of 20% over monolithic was explained in terms of the change to an intergranular fracture mode. 相似文献