钼粉处理新工艺对95%氧化铝陶瓷金属化质量的影响

Effects of Efficiently Dispersing Molybdenum Powder on the Quality of 95% Alumina Ceramics Metallizing

分别采用传统工艺和新工艺处理了陶瓷金属化用钼粉,并利用激光粒度分析、FESEM、X射线射、金相、扫描电镜、拉伸试验、氦质谱检漏等方法研究了处理前后钼粉的粒度及其分布、颗粒形貌、松装密度、氧含量、相组成,金属化膏层的表面状态,金属化层及界面组织,金属化层的封接强度和气密性。物理性能测试结果表明,新工艺处理钼粉的松装密度明显提高,氧含量增幅明显减小,且无杂相污染。配浆及丝网印刷试验显示,含新工艺处理钼粉的金属化料浆流动性好、固液比高,金属化膏层表面光亮细腻,金属化层致密度高。装管成品拉伸试验表明,含新工艺处理钼粉的金属化层的封接强度提高35%,拉伸后出现断瓷现象;这缘于钼粉容易烧结致密化并形成均匀连通的钼骨架。

Molybdenum powder used in ceramic metallization was dispersed by the traditional and ad- vanced processes. Particle size and distribution, granule morphology, apparent density, oxygen content, and phase composition of molybdenum powder before and after processing, the surface state of metalliza- tion paste, the microstructure, the sealing strength, and gas tightness of metallization layers were investi- gated by laser particle analysis, FESEM, XRD, metallographic analysis, SEM, tensile testing, and helium mass spectrometer leak detecting etc. The physical properties analyses show that the molybdenum powder dispersed by the advanced process, are characterized by apparent density increase, far less oxygen content change, and no impurity phases. The pulping and screen printing procedures demonstrate that the flow- ability and solid-liquid ratio of metallization slurry including the advanced molybdenum powder are im- proved, the surface of metallization paste is bright and smooth, and the compactness of metallization layer is high. The tensile testing for ceramic vacuum tubes reveals that the sealing strength of metallization layer containing the advanced molybdenum powder increases by 35% and the ceramic tube fracture after the tes- ting, which owe to easy sintering compactness for the molybdenum powder and formation of molybdenum metallic skeletons with homogeneous and connected pores.