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为了提高反应等离子喷涂纳米TiN涂层的致密性、消除涂层内的微观缺陷,在大气、氩气氛和真空中对其进行了热处理。用XRD、SEM、TEM分析了纳米TiN涂层热处理后相组成及组织结构的变化,测试了处理后涂层的结合强度和孔隙率。结果表明:纳米TiN涂层在大气和氩气氛中,于600℃开始发生分解和氧化;真空环境下加热,涂层相组成不发生变化。在大气中600℃加热处理后,TiN涂层中微裂纹愈合,孔隙率降到原来的70%,结合强度基本不变。大气中1000℃热处理后,晶粒尺寸仍为100～200 nm。
In order to improve the compactness of reactive plasma sprayed nano-TiN coating and eliminate the micro-defects in the coating, it was heat-treated in the atmosphere, argon atmosphere and vacuum. The phase composition and microstructure of the nano-TiN coating were analyzed by XRD, SEM and TEM. The bonding strength and porosity of the treated coating were tested. The results show that the nano-TiN coating begins to decompose and oxidize at 600 ℃ in the atmosphere and argon atmosphere, and the coating phase composition does not change under the vacuum environment. After heat treatment at 600 ℃ in the atmosphere, the micro-cracks in the TiN coating healed, the porosity dropped to 70%, and the bonding strength remained basically unchanged. After heat treatment in the atmosphere at 1000 ℃, the grain size is still 100-200 nm.