Ni-Cr合金与金刚石和钢基体界面微区的分析研究  

Micro-analysis of Interface between Ni-Cr Alloy and Diamond

作　　者：姚正军[1] 徐鸿钧[2] 肖冰[2] 武志斌[2] 

机构地区：[1]南京航空航天大学材料科学与技术学院,南京210016 [2]南京航空航天大学机电学院,南京210016

出　　处：《南京航空航天大学学报》2001年第4期311-314,共4页Journal of Nanjing University of Aeronautics & Astronautics

基　　金：国家自然科学基金 (编号 :5 9675 0 5 7)资助项目

摘　　要：利用扫描电镜 X射线能谱 ,结合金相及试样逐层的 X射线结构分析 ,剖析了 Ni-Cr合金与金刚石和钢基体钎焊界面的微区组织结构 ;揭示了 Ni-Cr合金对金刚石和钢基体表面的浸润和钎焊机理。即在钎焊过程中 ,Ni-Cr合金中的 Cr元素分离出在金刚石界面形成富 Cr层并与金刚石表面的 C元素反应生成 Cr7C3,在钢基体结合界面上 Ni-Cr合金和钢基体中的元素相互扩散形成冶金结合 ,这是实现合金层与金刚石和钢基体都有较高结合强度的主要因素。The brazing of a monolayer of diamond grinding wheel with active filler metals has distinct advantages over conventional electroplated diamond grinding wheel in terms of faster cutting and longer life. The study shows that a commercially available Ni-Cr alloy can be used as an active filler material for brazing diamond grit. Furnace brazing is carried out in a current of argon. SEM-EDS microanalyses show that during brazing the chromium present in the alloy segregated preferentially to the surface of the diamond to form a chromium-rich reaction product. X-ray diffraction reveals that the wetting and bonding behaviour on diamond surface by Ni-Cr alloy melt is realized through Cr 7C 3 which is produced by interaction between Cr atoms of Ni-Cr alloy and C atoms of diamond surface at elevated temperatures. The analyses also reveal that the bond between the alloy and the steel substrate is established through a cross-diffusion of iron and chromium. Finally a grinding test show that the wear modes of such a brazed grinding wheel are mainly grit fracture and attrition rather than grit dislodgement from the bond.

关 键 词：砂轮 单层 钎焊 金刚石 镍-铬合金 钢基体 界面微区 

分 类 号：TG74[金属学及工艺—刀具与模具]