放电加工用金属结合剂碳化硅工具的研究

Study on metal bond silicon carbide tools used for electrical discharge machining

本文利用热压烧结工艺制备了含有20vol％～50vol％SiC的放电加工用金属结合剂工具电极。采用非均相沉淀包裹法制得Cu包SiC复合粉体。并对试样的气孔率、电阻率、抗弯强度进行了研究，结果表明，随着SiC含量的增加，试样气孔率和电阻率提高，而抗弯强度下降；在20vol％-50vol％SiC含量范围内，采用直接混合法和包裹法制备的试样具有大致相同的气孔率、电阻率，但包裹法的强度却大大提高。用X—ray衍射、扫描电镜（SEM）、能谱分析（EDAX）等测试手段对试样进行了成分和微观形貌分析。研究结果表明，包裹法制得的Cu结合SiC试样，SiC分散更均匀，并通过形成Cu2O—SiO2共熔物（玻璃相）来提高SiC和Cu的界面结合强度。

In this paper, hot pressing technique was used to prepare metal bond silicon carbide tool electrods with 20 -50vol% SiC for electrical discharge machining. Cu coated SiC composite powder were made by heterogeneous precipitation coated method. The porosity, electrical resistivity and flexural strength of the tools were studied. The results show that the porosity and electrical resistivity of the tools increase, while the flexural strength decreases with an increase in SiC content; samples with 20 -50vol% SiC particles prepared by both coated and admixture methods have the same porosity and electrical resistivity, however, the flexural strength of samples made by coated method is better than that of samples made by admixture method. The composition and microstructure of samples were characterized by X - ray diffraction, SEM and EDAX. From these results, it can be concluded that the SiC particles distribute more uniformly in the samples made by coated method; the interface bonding strength between SiC and Cu in the samples made by coated method is improved through forming Cu2O- SiO2 eutectic （glass phase）.