热处理对氮化铝粉末抗水性的影响

EFFECT OF HEAT TREATMENT ON WATER RESISTANCE OF ALUMINUM NITRIDE POWDER

研究了氮化铝粉末在水蒸气／水环境中的化学稳定性，探讨了热处理工艺对氮化铝粉末抗水性的影响。热力学计算结果表明，氮化铝粉末即使在较低温度下也极易与空气中的水蒸气发生水解反应，分解为非晶态的ＡｌＯＯＨ，Ａｌ（ＯＨ）３晶相和ＮＨ３。水蒸气分压越高，水解反应趋势越强。在一定氧气分压气氛下，通过８００～９００℃的热处理，可使氮化铝粉末表面性质发生改变，并在其表面形成一层致密的氧化铝薄膜，从而抑制了氮化铝粉末的水解，提高了氮化铝粉末在湿环境中的化学稳定性。

The chemical stability of aluminum nitride powder under water vapor and/or aqueous environment was studied. Effect of heat treatment on the chemical stability and water resistance of the powder was also investigated. The thermodynamics calculation results show that AlN powder is easier to hydrolyse by the water vapor in ambient air to decompose amorphous AlOOH, bayerite Al(OH) 3 and NH 3 even at low temperature. The higher the partial pressures of water vapor, the stronger the hydrolysis reactions. The surface states of AlN powder can be modified by heat treatment in a controlled partial pressure oxygen atmosphere at 800 to 900℃ , and then the relative dense alumina film is formed on AlN powder surface by the oxidation of AlN. It is the oxide film that restrains hydrolysis reactions and increases the water resistance of AlN powder in wet envir on ment