CeO_2对Mo/Al_2O_3复合材料微观结构的影响

Effect of CeO_2 on microstructures of Mo/Al_2O_3 composite materials

采用无压烧结法制备含CeO2的Mo/Al2O3材料,用MM-200型环-块式摩擦磨损试验机测试该材料在滑动干摩擦条件下的磨损行为,通过X射线衍射(XRD)和电子探针对其微观结构和磨损后的形貌进行研究和分析。结果表明,添加CeO2的烧结样品中出现CeAl11O18相,且随CeO2含量(体积分数)增加,CeAl11O18逐渐增多,Al2O3相应减少。当CeO2的体积分数为6%时Al2O3全部由CeAl11O18取代;CeO2的添加使Al2O3和CeAl11O18相边界处均呈现圆钝形貌,并且存在Mo、Al、O的相互扩散区域。磨损形貌表明,1 730℃烧结的样品中出现摩擦转移层,当CeO2含量达到4%时,该摩擦转移层大量出现,从而改善材料的耐磨性。

Molybdenum-alumina（Mo/Al2O3） composites with different volume fraction of Ceria（CeO2） were prepared by pressureless sintering.The microstructure and wear resistance were studied by XRD and electron microprobe.The results show that the new phase of CeAl11O18 is found with the addition of CeO2.The amount of CeAl11O18 increases and Al2O3 decreases with the increasing of CeO2.Al2O3 completely disappears and replaced by CeAl11O18when the volume fraction of CeO2 is 6%.The interdiffusion of Mo,Al and O elements at the Al2O3 and CeAl11O18 phases boundary is promoted by CeO2.The wear microstructure research shows that tribolayers can be found in Mo/Al2O3 composites sintered at 1 730 ℃.Massive tribolayers appear when the content of CeO2 is 4%（volume fraction）,which increase the wear resistance.