Ni-Cr合金钎焊镀钛金刚石的研究

本文利用真空炉中钎焊的方法,采用Ni-Cr合金钎料,适当控制钎焊温度,保温时间和冷却速度,实现了镀钛金刚石与钢基体的高强度连接.并用深腐蚀处理钎焊后的试样,使金刚石脱离基体,用扫描电镜,X-射线能谱,对金刚石表面的碳化物进行了分析,剖析了Ni-Cr合金与镀钛金刚石的接口微区结构.结果表明:在钎焊过程中,钎料在金刚石表面形成富铬层并与金刚石表面的C元素反应生成Cr7C,和Cr3C2,其中Cr7C3呈笋状生长,Cr3C2呈片状生长,而Ti却并没有在表面形成碳化物.这主要是因为Ti元素与Ni的结合力大于Ti与C的结合力,因此,实现Ni-Cr合金与镀钛金刚石高强度冶金结合的,是活性钎料中的Cr元素.

Study on brazing of Ti - coated diamond with Ni - Cr filler

In this paper,vacuum furnace brazing test was carried out using Ni-Cr alloys as brazing filler metals.Proper brazing temperature,heat preservation time and cooling speed helped to realize a strong bonding between Ti-coated diamond and steel substrate.Then the brazed sample was deeply eroded so that diamond divorced from steel substrate.SEM and EDS were used to analyze the carbides in the diamond surface and the microstructure interface between Ni-Cr alloys and coated diamond.The results showed that the Ni-Cr alloys reacted with C in the diamond surface to form Cr_7C_3 in shape of asparague,and Cr_3C_2 in shape of flake.However there was no Ti-carbide in the surface of the diamond.The main reason was that the interaction between Ti atoms and Ni atoms was stronger than that between Ti atoms and C atoms.So it was the Cr element in active fillers that made a strong bonding between Ni-Cr alloys and Ti-coated diamond.