超高分子量聚乙烯/纳米TiO_2复合材料的摩擦磨损行为

Tribological Behavior of Nano-TiO_2 Filled Ultra High Molecular Weight Polyethylene Composites

用热压成型法制备了纳米TiO2填充超高分子量聚乙烯(UHMWPE)复合材料,采用销-盘式摩擦磨损试验机考察了复合材料在干摩擦条件下与45#钢配副时的摩擦磨损行为,采用扫描电子显微镜观察了复合材料磨损表面形貌。结果表明,填充质量分数为15%的纳米TiO2能显著改善UHMWPE的耐磨性能。纯UHMWPE的摩擦过程中呈现出一次磨合期、一次稳定期、二次磨合期和二次稳定期四个明显的特征。当填充质量分数为15%的纳米TiO2时,UHMWPE基复合材料的摩擦过程中二次磨合特征已基本消失,整个摩擦过程的基本特征主要表现为磨合期和稳定期两个阶段,且磨合时间明显缩短,同时复合材料的磨损表面出现了明显的贫Ti区和富Ti区,其磨损机制主要表现为粘着磨损,局部磨损表面呈现了轻微的塑性变形特征。

Ultra high molecular weight polyethylene （UHMWPE） based composites filled with nanometer TiO2 were prepared by heat compression molding.The friction and wear behaviors of the resulted composites sliding against AISI-1045 carbon steel disc under dry ambient condition were evaluated on a pin-on-disc test rig.The worn surfaces of the composites were observed on a scanning electron microscope.The results show that the wear-resisting property of the UHMWPE based composites filled with 15%nano-TiO2 is remarkably improved.There are four obvious characteristics which are primary running in period,primary steady period,second running in period and second steady period during the friction process of pure UHMWPE.When the mass fraction of nano-TiO2 is up to 15%,the characteristic of second running in period disappears essentially during the friction process of the UHMWPE based composites.There are two main periods which are running in period and steady period during the whole friction process of the composites,and running in time is shortened obviously.There are two zones on the worn surfaces of the composites,one is lack of Ti,and the other is abundant in Ti,and the main wear mechanism is adhesive wear,and mild plastic deformation appears on local worn surface.