镀膜金刚石与铜基结合剂间把持力提高方法探讨

在不改变成分的条件下,为了探讨将表面镀覆和表面刻蚀相结合来提高金刚石与金属结合剂把持力的方法和条件,将镀Ti、镀Cr和镀Ni金刚石在1050℃下保温1 h后,用真空热压烧结法制备未镀、高温处理前后镀覆金刚石的铜基结合剂样条。用扫描电子显微镜对金刚石镀层表面形貌进行观测,用金刚石高温热处理前后铜基结合剂样条的抗弯强度来评估金刚石与铜基结合剂的把持力,经1050℃高温处理1 h后,金刚石表面的镍镀层基本上保持完整,而钛镀层和铬镀层则出现脱落;镀覆金刚石的单颗粒抗压强度都下降;镀Ti和镀Cr金刚石铜基结合剂样条的抗弯强度下降,但镀Ni金刚石样条的抗弯强度却大幅度提高,达到833 MPa,增幅为12.1%。结果表明:只有高温处理后镀层保持完整而且镀层能使金刚石表面粗糙度提高的情况下,才能大幅度提高金刚石与金属结合剂之间的把持力。

Discussion on Improving the Holding Force Between CoatedDiamond and Cu-Matrix Binder

In order to investigate the methods and conditions for improving the holding force between diamond and metal-bond by combining surface plating and surface etching without changing the composition,Ti-coated,Cr-coated and Ni-coated diamond were kept at 1050 ℃ for 1 h,and the Cu-matrix bonded diamond segments were prepared by vacuum hot-pressing sintering. The surface morphology of diamond coating was observed by scanning electron microscope,and the flexural strength of sintered samples before and after high temperature treatment was tested to evaluate the holding force between diamond and Cu-matrix binder. After high temperature treatment at 1050 ℃ for 1 h,Ni coating on diamond surface was almost intact,while the Ti and Cr coatings fell off,and the compressive strength of coated diamond particles all decreased. The flexural strengths of Ti-coated and Cr-coated diamond Cu-matrix bonded segments both decreased,but the one of Ni-coated diamond segments significantly increased to 833 MPa,an increase of 12.1 %. The experimental results showed that the holding force between diamond and metal-bond can be greatly improved only when the coating on the diamond surface remained intact and the coating can improve the surface roughness of the diamond after high temperature treatment.