大尺寸三元复合稀土钨坯条烧结工艺研究

Research on the Sintering Process of Large Size Ternary Rare Earth Tungsten Billets

对大尺寸(Φ20 mm)三元复合稀土钨坯条的烧结工艺进行了研究。通过在低温阶段(≤1800℃)增加烧结时间、高温阶段(≥2000℃)增加烧结时间、高温阶段增加保温平台的方法进行烧结。结果表明:在1800℃以下,烧结时间短容易形成大孔洞及出现“烧生现象”造成密度低,而在高温烧结阶段延长烧结时间稀土元素扩散挥发现象严重,造成坯条内稀土元素分布不均匀,通过在低温阶段增加烧结时间,高温阶段增加保温平台缩短保温时间的方式可以抑制稀土元素的扩散,挥发密度可达18.2 g/cm^(3)。

The sintering process of large size(Φ20 mm)ternary rare earth tungsten billets was studied.The sintering process was carried out via increasing the sintering time at a low temperature stage(≤1800℃),increasing the sintering time at the high temperature stage(≥2000℃),and increasing the insulation platform at the high temperature stage.The results show that for the sintering temperature below 1800℃,it is easy to form large holes and under-sintering phenomenon that lead to the low density.Prolonging the sintering time at the high temperature sintering stage will cause serious diffusion and volatilization of rare-earth elements,resulting in uneven distribution of rare earth elements in the billet.With increasing the sintering time at the low temperature stage,increasing the insulation platform and shortening the holding time at the high temperature stage can inhibit the diffusion and volatilization of rare earth elements and make density reach to 18.2 g/cm^(3).