氧化铝陶瓷热浸镀铝工艺研究

Study on Dip-Coating of Al_2O_3 Ceramics with Al

作者发现采用热浸镀铝工艺,在一些特殊的条件下将陶瓷插入铝熔液中定向移动后移出,可以在氧化铝陶瓷表面镀上一层厚度为数微米的铝膜。本实验系统地研究氮气流量、铝熔液温度以及陶瓷板与铝液的接触时间等因素对陶瓷表面铝膜覆盖率的影响。结果表明:铝膜覆盖率随氮气流量的增加发生显著变化,先增加后降低;铝熔液温度的提高使得覆盖率峰值对应的氮气流量向低氮气流量侧转移;铝熔液和陶瓷接触时间的增加有助于陶瓷表面热浸镀铝。此外还采用高分辨透射电镜观察了铝膜和陶瓷的连接界面,发现在氧化铝晶粒上外延生长出与铝晶粒之间存在共格关系的新生Al2O3层。

Theoretically, Al can not grow in a layer-by-layer growth mode (FM) on Al2O3. However, we explore that a layer of Al film, with a thickness of several micrometers, can be coated on Al2O3 ceramics by adopting a dip coating method under appropriate conditions. Systematical research has been done on the influence of flow rate of nitrogen gas, temperature of molten aluminum, contact time between ceramic plate and liquid aluminum on the coverage rate of the aluminum film on Al2O3 ceramics. The results indicate that the coverage rate increases progressively with increasing flow rate of N2 gas, and drops gradually after approaching maximum values, while the moderate flow rate of N2 gas descends as the temperature of Al melt increases. Increasing the contact time of molten aluminum to the ceramics can increase the coverage rate. High-resolution transmission electron microscopy shows that new α-Al2O3 crystals grow at Al/Al2O3 interface, with their lattices being matched well with the crystals of both Al2O3 and Al.