Co含量对一种Ni-Co-Al粉末高温合金摩擦学性能的影响

Effect of Co Content on Tribological Behavior of Ni-Co-Al P/M Superalloy

采用粉末冶金(机械合金化+真空热压烧结)制备不同Co含量的Ni-Co-Al系高温合金,并考察合金在800℃下的高温摩擦学性能与Co含量的变化关系。结果表明:适量的Co可以提高合金的硬度和抗压强度,并改善合金的摩擦学性能,但过量的Co(Co质量分数达到30%)又使合金的摩擦学性能变差。磨痕表面的扫描电子显微镜(SEM)和X射线光电子能谱(XPS)及能谱(EDS)分析表明,磨痕表面形成了由CoO等组成的氧化物"釉质层"。这层"釉质层"的成分及其在摩擦过程中的脱落程度影响了合金的高温摩擦学性能。

Ni-Co-Al high temperature alloys with different Co content were prepared by powder metallurgy(mechanical alloying and hot-press sintering), of which the high temperature tribological properties were investigated at 800℃. The results showed that the hardness and compressive strength, as well as the tribological properties of alloys could be improved with a Co addition in a range from 5-30 mass%,among which 20 mass% is the optimal. The observation of worn surfaces by SEM, XPS and EDS revealed that a'glaze-like film'consisted of CoO and other oxides existed on the worn surface. The high temperature tribological properties of the alloys are highly related with the composition and the spallation tendency of the formed glaze film during the friction and wear process.