Study on Wear of a Ceramics/Metal Composite

为了了解复合材料的摩擦磨损特性，对一种由陶瓷(MnNiO陶瓷)和金属(CoNbZr非晶态金属)组成的复合材料滑块进行了摩擦磨损试验。结果表明，复合材料的总磨损率在一定程度上服从逆规律。这一逆规律对材料设计是有用的，因为利用该规律可以预测复合材料的总磨损量。另一方面，当复合材料磨损时，成分之间通常会形成具有水平差的不平坦的磨损面。为了了解复合材料的磨损机理，有必要弄清表面不平整的形成机理。进行了复合材料在不平整表面上的磨损试验，并以外加载荷和滑动速度作为试验条件参数。观察到陶瓷表面和金属表面的形状和水平差强烈地依赖于滑动条件。其显著特点是：(1)随着压力的增大，组分之间的液位差变大。(2)在大压力、高滑动速度的情况下，陶瓷表面前缘出现鹰鼻形状，金属表面前缘出现较深的凹槽。本文还利用弹性理论和热传导理论对不平整表面的形成机理进行了理论分析。数值分析表明，成分的弹性变形和摩擦加热引起的局部强度降低是形成复合材料不均匀磨损表面的重要原因。

In order to understand characteristics of friction and wear of composites, a composite slider consisting of ceramics (MnNiO ceramics) and metal (CoNbZr amorphous metal) is tested against a rotating disk made of zirconia. The results show that gross wear rate of composites is governed by the inverse rule to some extent. The inverse rule is useful for material design since it is possible to predict gross wear volume of composites by using the this rule.On the other hand, when a composite material is worn out, an uneven worn surface with a level difference is generally formed between constituents. It is necessary to clarify the mechanism of formation of the uneven surface in order to understand the mechanism of wear of composites. We carry out wear tests of composites with respect to the uneven surface, and then take applied load and sliding velocity as parameters of test conditions. It is observed that the shape and the level difference between ceramics surface and metal surface strongly depend on the sliding conditions. The notable features are as follows: (1) With the increase of pressure, the level difference between constituents becomes large. (2) In case of large pressure and high sliding velocity, a shape like a hawk nose appears at the leading edge of ceramics surface and a relatively deep groove at the leading edge of metal surface. In this study, the mechanism of formation of the uneven surfaces is also investigated theoretically by using the theories of elastisity and heat conduction. It is obtained from the numerical analysis that elastic deformation of constituents and local reduction in strength due to frictional heating play important roles in forming uneven worn surfaces of composites.