粉末注射成形纯钨的活化烧结致密化研究  

Research of Active Sintering Densifying on Powder Injection of Molding Pure Tungsten

作　　者：罗铁钢[1] 蔡一湘[1] 曲选辉[2] 秦明礼[2] 

机构地区：[1]广州有色金属研究院粉末冶金研究所,广州510650 [2]北京科技大学材料科学与工程学院,北京100083

出　　处：《机械工程学报》2013年第18期63-68,共6页Journal of Mechanical Engineering

基　　金：教育部长江学者和创新团队发展计划资助项目(I2P407)

摘　　要：采用添加微量元素对粉末注射成形钨零件进行活化烧结的方法,实现在较低烧结温度下获得较高致密度的纯钨制品,应用扫描电子显微镜和透射电子显微镜检测分析其断口形貌、显微组织及能谱,应用阿基米德法测量样品的密度,研究微量元素对制品金相组织、显微断口和密度的影响。研究结果表明,Ni在低温烧结时对提高钨制品的密度作用显著,而Y2O3在高温烧结时对钨制品密度提高的作用明显。添加微量镍能显著降低钨的烧结温度,镍质量分数为0.8%时,在1 580℃湿氢气氛下烧结后,粉末注射成形钨零件的相对密度达到99.12%。添加微量的Y2O3能提高钨烧结致密度,而且还能细化晶粒,添加0.3%的Y2O3在2 280℃烧结,钨的相对密度可达95.15%。其活化烧结机制主要是Y与W在高温下发生了界面反应,从而降低烧结系统的自由能,促进烧结。To achieve higher density of pure tungsten products at lower sintering temperatures, the powder injection molding W parts are sintered by active sintering technique with element addition. The effects of doped elements on the microstructure, micro-fracture and density are investigated by scanning electron microscope（SEM）, transmission electron microscope（TEM） and Archimedes measurement. The results show that Ni can improve the density of tungsten products significantly at the low temperature sintering, and Y2O3 has an obvious effect density increase of tungsten products at the high temperature sintering. A small amount of Ni addition can reduce the sintering temperature. With 0.8% Ni addition, the density of W reaches 99.12% at a sintering temperature of 1 580 ℃ in wet H2-atmosphere. Adding a small amount of Y2O3 can also increase the density of W and reduce the grain size. The density of W achieves 95.15% atter sintered at 2 280 ℃for 0.3% Y2O3 addition. The sintering mechanism is discussed. The interface reaction between Y and W at high temperatures reduces the free energy of system and promotes the sintering process.

关 键 词：粉末注射成形 纯钨 活化烧结 

分 类 号：TF124[冶金工程—粉末冶金]