AlN粉体表面抗水解涂层的制备及其对AlN陶瓷热导率的影响

Preparation of a Hydrolysis-Resistant Coating on AlN Pow-der Surface and Its Effect on Thermal Conductivity of AlN Ceramic

摘要:

提升AlN陶瓷粉体的抗水解性能对于其储存和成型加工至关重要。使用一种抗水解涂层作为阻止水分与AlN表面接触的屏障，以提升AlN粉体的抗水解性能。采用化学沉淀工艺在AlN粉体表面制备均匀、全包覆的非晶Y₂O₃涂层。利用TEM、XPS和Zeta电位测试详细研究了包覆层的有效性和完整性。通过测试室温下水基AlN悬浮液的pH-时间曲线以研究AlN粉体的水解性能。结果表明，经包覆处理的AlN粉体能够在水中保持稳定至48 h，这说明Y₂O₃表面包覆处理可以有效钝化AlN粉体，从而避免了其水解反应的发生。此外，与球磨工艺引入烧结助剂相比，化学沉淀工艺有利于提升AlN陶瓷的热导率。

Abstract:

Improving the hydrolysis resistance of AlN ceramic powder is crucial to the powder storage and shaping processing. In order to improve the hydrolysis resistance of AlN powder, a hydrolysis-resistant coating was used to act as a barrier layer to prevent water from contacting with the AlN surface. An amorphous Y₂O₃ coating was uniformly deposited and fully wrapped on the surface of AlN powder via a chemical precipitation process. The coating effectiveness and integrity were investigated by TEM, XPS and Zeta potential measurements. The hydrolytic behavior of AlN powder in an aqueous suspension was studied by following the pH vs. time at room temperature. The results show that the coated AlN powder is stable in water within 48 h, indicating that the surface coating treatment with Y₂O₃ can effectively passivate AlN powder against hydrolysis. Moreover, as a way to introduce the sintering additives, the chemical precipitation process can favor an improvement of thermal conductivity of the sintered AlN ceramic, compared with the conventional ball-milling process.