机械模具导向滑板Fe-Mo-石墨自润滑材料摩擦学性能研究

Tribological Properties of Fe-Mo-graphite Self-Lubricating Composite for Guiding Plate Used in Mechanical Mould

采用粉末冶金工艺,制备了3种不同石墨含量的Fe-Mo-石墨自润滑材料,测定了3种材料的密度、硬度和抗压强度,并对材料的组织和不同摩擦速率下的摩擦学性能进行分析和研究,最后采用扫描电镜(SEM)和X射线衍射仪(XRD)对磨痕表面形貌和成分进行表征。结果表明,复合材料中石墨添加质量分数为1.0%时,材料组织以铁素体为主相,此时的摩擦系数较为稳定,磨损率随摩擦速率的提高而增大,磨损机制主要为粘着磨损;石墨添加质量分数高于1.0%时,材料组织以珠光体为主相,摩擦系数随摩擦速率提高而增大,但磨损率随之减小,且摩擦速率高于0.5m/s时,磨损率量级为10^(-8)cm^3/N·m,属于轻微磨损。材料中珠光体、Fe_2MoC的生成,以及摩擦过程中生成的Fe_2O_3、Fe_3O_4是Fe-Mo-石墨材料在高的摩擦速率下具有优良耐磨性的主要原因。

Fe-Mo-graphite self-lubricating composites with three different contents of graphite were prepared using PM technology. The density, hardness, compressive strength and the microstructure of sintered alloy were measured and analyzed, respectively. The morphology and composition of the worn surface at different friction velocity were also investigated by SEM and XRD. The results show that microstructure of the composite is mostly ferrite, the friction coefficient is stable and the wear rate increases with the increasing friction velocity when the graphite content is 1.0 wt%, the wear mechanism is mainly adhesive wear. When the graphite content surpasses 1.0 wt%, the microstructure of the composite is mostly pearlite, the friction coefficient increases while the wear rate de- creases with the increasing friction velocity. The order of wear rate is 10.8 cm3/N· m as the friction velocity higher than 0.5 m/s, which belongs to mild wear. The formation of pearlite and Fe2MoC in the alloy, as well as the forma- tion of Fe203 and Fe304 on the worn surface is the main reason why the composite has good wear resistance.