基于真空冷冻干燥和高真空微波烧结方法制备TiN-Cu电火花电极

Fabrication of TiN-Cu Electrical Discharge Machining Electrode by Vacuum Freeze Drying and Microwave Sintering

探索真空冷冻干燥和高真空微波烧结方法对TiN-Cu电火花加工用(EDM)电极性能的影响。经过高能球磨混合TiN粉末和Cu粉末、浆料制备、干燥、烧结等工艺制备出电火花加工用电极。对比了真空干燥与真空冷冻干燥、真空管式烧结与高真空微波烧结等工艺性能,采用正交实验方法探索高真空微波烧结最佳工艺参数组合,并且通过电子扫描电镜观察EDM电极形貌。试验表明:真空冷冻干燥制备坯体收缩率较小;在微波烧结在烧结温度1200℃、保温时间20 min、升温速率15℃/min工艺参数下,制备出TiN-Cu EDM电极相对损耗率为3.55%,比商业上应用的紫铜EDM电极相对损耗率低。

The TiN-Cu electrical discharge machining(EDM) electrode was fabricated by vacuum freeze drying and high-vacuum microwave sintering,instead of conventional vacuum drying and sintering via resistive heating.The influence of the fabrication conditions,including the pressure,freezing,microwave power,sintering temperature/time and heating rate,on the quality of TiN-Cu EDM electrode was investigated through orthogonal experiment and with scanning electron microscopy to optimize the fabrication conditions.The results show that the freeze-drying combined with microwave sintering in vacuum significantly improved the quality of TiN-Cu EDM electrode.For instance,under the optimized conditions,the new TiN-Cu EDM had a relative loss-rate of 3.55%,much lower than that of commercially Cu-EDM electrode.The possible mechanisms,explaining the lower blank shrinkage rate and smaller relative loss-rate of TiN-Cu EDM electrode,were also tentatively discussed.