向NI-Cr合金中添加Ni/C制备自润滑金刚石工具（英文）

Manufacturing of self-lubricating diamond tools with Ni-Cr alloy adding with Ni/C

利用添加3%、5%的Ni-Cr合金在保护气氛炉中制备金刚石试样,钎焊温度为1 050℃,保温5 min。采用扫描电镜分析钎焊金刚石形貌和钎缝的微观组织,维氏硬度计测量接头的硬度。结果表明:添加Ni/C的Ni-Cr合金对金刚石具有较好的润湿性,可以实现高强度连接,碳化物在金刚石表面形核和结晶长大,与金刚石表面的原子分布具有一定位向关系。钎缝中形成的空心Cr7C3和簇状共晶石墨与添加的Ni/C有关,钎焊层中有少量Ni/C剩余,硬度从830HV0.2降低到700HV0.2,这有利于降低钎焊热应力和金刚石后期的出露高度。

Ni-Cr alloy adding with Ni / C of 3%,5% was utilized to braze diamond grains in protective furnace with the temperature 1 050 ℃ and holding time 5 min,respectively. Diamond morphology and the brazed joint microstructure were analyzed with the help of scanning electron microscope; the brazed joint hardness was measured by Vickers. The results show that Ni-Cr alloy adding with Ni / C has good wettability with diamond; it could achieve high strength bonding between diamond and brazing layer. Carbide crystallizes and nucleates on the surface of diamond has an orientation relationship with diamond surface. The Cr7C3 morphology is hollow and clusters eutectic graphite forms in the brazing layer,which has a relationship with the adding Ni / C. There is small amount of Ni / C within brazing layer,the brazed joint hardness falls from 830 HV0. 2 to 700 HV0. 2,this is benefit to decrease the thermal stress and improve the protrusion of diamond in the later grinding.