金刚石镀覆及热处理在金刚石工具中的应用

Application of diamond coating and heattreatment ondiamond tools

探究了金刚石镀覆工艺及镀覆金刚石热处理对提高金刚石在胎体中把持力的作用。结果表明850°C真空镀铬的金刚石镀层中能检测到存在Cr7C3相,而化学镀铬的金刚石需经高温真空热处理后才能检测到Cr7C3,真空镀钛的金刚石热处理前后均没有检测到碳化物相。镀钛金刚石镀层改善了金刚石与金属胎体的浸润性,提高了金刚石的机械把持力,制备的组合绳锯切割寿命由3.44 m^2/m提高到了3.79 m^2/m。镀铬金刚石镀层改善浸润性提高机械包镶与Cr7C3相产生的化学结合力共同作用,提高了金刚石把持力;使用热处理真空镀铬金刚石的组合绳锯测试寿命提高到了3.95 m^2/m,而化学镀铬金刚石由于镀层过厚,在烧结中金刚石与镀层热膨胀差异导致结合层破裂,把持力减弱,组合绳锯寿命仅为3.50 m^2/m。

Enhancingtheholding forceof diamond in metal matrix by diamond coating and heat treatment was investigated.Cr7C3wasfoundon the coat ofthe diamondcoated with Crin vacuumat 850℃,but it was detected in the diamond coated with Crby chemical treatmentand heated at 900℃.Furthermore,there wasno carbidein the diamond coated with Ti,even after an vacuum heattreatment.The wettability between diamond and metal matrix was improved by the Ti coating,and the lifetime of muti-wires with Ti coating diamondwas increased from 3.44 m^2/m to 3.79 m^2/m.The Crcoatinglayer could enhance the bonding strength between diamond and metal matrix bymechanical holding forceand chemical bonding force.The lifetime of multi-wireswith Crcoating diamond which coated in vacuum was increased to 3.95 m^2/m.Butthe Crcoating layer ondiamond by the chemicalcoat process was too thick,whichmade the bond to be brokeneasily during the sinteringprocess due to the different thermal expansionof diamond and coating layerand decreased the holding force of diamond.In resultthelifetimeof multi-wires were only 3.50 m^2/m.