蓝宝石钨金属化层显微分析

Microscopic Analysis of Tungsten Metallization Layer for Sapphire

采用扫描电镜和X射线衍射仪对不同烧结温度和不同烧结次数获得蓝宝石钨金属化层进行了显微分析,进而探讨了蓝宝石钨金属化的机理。显微分析结果表明:蓝宝石钨金属化温度较低时,金属化层发黑、掉粉、体积收缩小;温度达到1850℃时,金属化层连续、致密,焊接后结构完整,界面清晰;温度达到1900℃时,金属化层液相外溢,表面龟裂;最佳烧结温度约1850℃。一次涂膏进行1450℃低温预烧结,再第二次涂膏进行1850℃高温烧结可以得到比较理想的金属化层。蓝宝石钨金属化过程包含化学反应过程和钨液相烧结过程,界面产物为Al5Y3O12。

By using scanning electron microscope and X-ray diffraction, tungsten metallization layer with different sintering temperatures and different sintering times for sapphire was analyzed. The metalli- zation mechanism was also discussed. The microscopic analysis results show that at a relatively low sinte- ring temperature, the metallization layer is black, powder falling and with a small shrinkage. When the temperature reaches 1850℃, the layer is continuous and compact, the welding structure is complete and the interface is clear. When the temperature reaches 1900℃, liquid spilling occurs with surface cracking. So the optimal sintering temperature is 1850℃. With a two-step sintering process, the first coating paste is sintered at 1450℃ and then the second coating paste is sintered at 1850℃, an ideal metallization layer could be obtained. Tungsten metallization process on sapphire is composed of chemical reaction and liquid phase sintering of tungsten. The reaction product is Al5 Y3O12.