Effect of Sintering Temperature on Preparation of W-La2O3-Y2O3-ZrO2 Rare Earth Tungsten Electrode by Spark Plasma Sintering

The rare earth tungsten electrode was prepared by spark plasma sintering (SPS) with W-La2O3-Y2O3-ZrO2 composite powders synthesized by second-time reduction as raw materials. And the effects of SPS sintering temperature on the microstructure and hardness of sintered rare earth tungsten electrode were studied. The structure and morphology were investigated by metallographic microscope, scanning electron microscopy and Vickers Indenter, and the density degree of rare earth tungsten electrode sintered sample were analyzed based on Archimedes Principle. Sintering process was performed at a temperature range of 1200-1500 degrees C for a dwell time of 5 min under an external pressure of 50 MPa in vacuum, the optimum sintering temperature of sintered rare earth tungsten electrode was 1450 degrees C; with the increase of sintering temperature, the tungsten grains in the microstructure of the sintered sample grew gradually, the relative density and the hardness of the sintered sample also increased. Tungsten grain growth can be effectively inhibited by spark plasma sintering, which prompts fine grain strengthening of the tungsten electrode, and it is possible to prepare a high densification and fine grain structure rare earth tungsten electrode.