超高频感应连续钎焊立方氮化硼磨粒的界面反应机理

摘要

采用超高频感应连续钎焊工艺，在不同扫描速度条件下实现了立方氮化硼(CBN)磨粒、Ag-Tu-Ti合金以及基体三者之间的钎焊连接。采用扫描电子显微镜(SEM)和X射线能谱仪(EDX)观察钎焊后的CBN磨粒界面新生化合物形貌。结果表明：随着扫描速度的变化，在CBN磨粒表面生成颗粒状TiN化合物以及针状和六棱柱状的TiB 2化合物。其中，TiN尺寸为100 nm左右，而TiB 2尺寸小于200 nm。在超高频感应连续钎焊CBN磨粒表面首先生成颗粒状TiN层，然后在TiN层外围形成柱状TiB 2层，最终形成CBN/TiN/TiB 2/钎料结构。当扫描速度为0.5 mm/s时，可以获得较好的界面新生化合物层结构。%Continuous brazing with ultra-high frequency induction was proposed to braze the cubic born nitride (CBN) grits and steel substrate based on Ag-Cu-Ti filler alloy. The new compounds morphologies were observed and analogized by scanning electron microscopy (SEM) and energy diffraction X-ray (EDX). The results show that, with the variation of scanning speed, granular compounds TiN about 100 nm in size, the needle-like and prismatic compounds TiB 2 less than 200 nm in size are observed, respectively. The theoretical analysis results reveal that, during continuous brazing by ultra-high frequency induction, granular TiN layer forms on the surface of CBN firstly, and then, prismatic TiB 2 layer forms on the outside of the new TiN layer. The joint is CBN/TiN/TiB 2/filler structure, finally. A satisfactory interfacial structure can be obtained when scanning speed is 0.5 mm/s.