摘要
Nickel-plated graphite particles and unmodified graphite particles with different contents were added to the Fe-based diamond composites.The basic properties of those specimens were measured,including relative density,hardness,bending strength,abrasion ratio and holding force coefficient.And also,SEM,XRD and EDS were used to carry out microstructure characterization,phase analysis and element distribution of these specimens.The results show that nickel plating effectively improves the surface wettability of graphite particles.And it is determined that an element diffusion zone is formed on the transition interface between the nickel-plated graphite and the matrix materials,effectively enhancing the interfacial bonding strength.Also,the pores and cracks in the matrix generated by adding the graphite particles are reduced after nickel plating.Thus,the loss of basic properties of the specimens is restrained.But it is found the higher the graphite content is,the weaker the positive effect of nickel plating is.In addition,it is revealed that nickel plating plays a conducive part in the formation of graphite lubricants on the working surface,and nickel-plated graphites can slow down the thermal corrosion of the diamond particles inside the high-temperature sintered specimens.
将不同含量的镀镍石墨颗粒和未经处理的石墨颗粒添加到铁基金刚石复合材料试样中,采用SEM、XRD和EDS对试样进行微观结构表征、物相分析和元素分布测试,并测定试样的相对密度、硬度、弯曲强度、磨损量及其胎体对金刚石的包镶能力。结果表明,镀镍能有效改善石墨颗粒的表面润湿性,并在镀镍石墨和胎体组织间的过渡界面上形成元素充分扩散的区域,这有效增强石墨颗粒与胎体组织间的界面结合强度。镀镍后石墨颗粒在胎体组织内部形成的孔隙和裂纹减少,因此,镀镍能抑制由于添加石墨颗粒给试样造成的基础性能损失,但添加物含量越高,镀镍的抑制效果越差。此外,镀镍能够有效保障工作面上石墨润滑物的形成,且高温烧结下镀镍石墨有助于减轻试样内部金刚石颗粒的热腐蚀。
