陶瓷─铸铁摩擦面上形成的表面膜对其摩擦学特性的影响

^EFFECT OF TRIBOFILM FORMATION ON THETRIBOLOGICAL CHARACTERISTICS OF CERAMIC-CASTIRONSLIDING PAIRS

在Ｍ─２００环─块磨损试验机上研究了陶瓷─铸铁配副在蒸馏水和空气润滑下的摩擦学特性，并以陶瓷─碳钢配副作为对比，对磨损后的试样磨面进行了扫描电镜和光镜观察，采用俄歇电子能谱（ＡＥＳ），Ｘ射线能谱（ＥＤＡＸ）以及图象分析等方法对表面膜进行了分析。结果表明：Ｓｉ３Ｎ４陶瓷与铸铁在蒸馏水润滑下配副获得了非常优异的摩擦学特性，其摩擦系数仅为０．０２，系统的磨损率几乎接近于零，其原因是由于在磨面上形成了具有一定厚度和面积的化学反应膜；当Ｓｉ３Ｎ４与碳钢在蒸馏水润滑下配副时，由于在磨面上不能形成有效的化学反应膜，所以摩擦系数仍然崐较高；当Ａｌ２Ｏ３与金属配副时，在陶瓷磨面上形成了材料转移膜，转移膜的形成大幅度减轻了陶瓷磨损，但却加剧了金属的磨损。

Using distilled water and air as lubricants, the wear tests of ceramic - cast iron pairs are carried out on a M - 200 type ring - block wear testerl For comparison, the ceramic - carbon steel psirs are also tested under the same conditions. The worn surface of specimens are obaerved under scanning electron microscope and optical micro- scope . Furthemore, the tribofilms are analyzed by using Auger electron spectroscopy ( AES) , energy - dispersive X ray spectroscopyf (EDAK) and image analysis technique . ln the wear test of Si3 N4 - cast iron pairs lubricated with distilled water, the friction coefficients of the pairs are just 0.02 , and the wear rates of ceramic and iron are near ze- ro . The reason why such superior tribological characteristics can be caused is that a trbochemical film, which has e- nough thickness and area, is formed on the wearing surfaces . However, in the test of Si3 N4 - carbon steel pair lubri- cated with distilled water, the friction coefficient is still high because the trilaochemical film formed on the wearing sucface is too thin and too small . A metal transfer film is formed on the ceramic surface when the ferrous metals slide against the Al2O3 ln this situation, the wear amount of Al2O3 is quite small, but the wear amount of metals is large and the friction coefficient is rather high .