高温氧化行为的影响
(中国科学院 金属研究所， 沈阳 110016)
摘 要: 将原始喷涂态和表面抛光态的NiCrAlY涂层在1050℃恒温氧化300h， 利用XRD, SEM, EDS方法， 测定涂层的氧化物及其相转变， 分析表面氧化膜的生长破坏行为。 结果表明: 两种涂层在1050℃保温， 在150h以内均能生成α-Al2O3氧化膜； 150h后， 抛光态涂层保护性氧化膜被破坏， 抗氧化能力下降， 喷涂态涂层表面粗糙， 连续Al2O3保护膜的形成较晚， 氧化早期氧化膜中存在微裂纹， 可释放应力， 有利于氧化膜与涂层的结合。 氧化动力学曲线符合抛物线规律， 氧化至300h， 表面氧化膜只有少量微裂纹， 无剥落。 说明喷涂态涂层的长期恒温抗氧化能力比抛光态涂层强。
关键字: NiCrAlY涂层； 表面状态； 高温氧化； 氧化膜
on its high-temperature oxidation behavior
（Institute of Metal Research, The Chinese Academy of Sciences,
Shenyang 110016, China）
Abstract:NiCrAlY coatings with two surface roughnesses, as-sprayed and polished state, were isothermally oxidized at 1050℃. The oxides formed on the coating surface and their transformation were determined by means of XRD, SEM and EDS. The growing-up behavior of oxide scale and its failure were analyzed also. The results show that, when oxidized for less than 150h, two coatings can both form the scale mainly consisting of α-Al2O3 and a little Ni(Al,Cr)2O4 spinel; after oxidized for more than 150h, the protective oxide scale of the polished coating begins to spall, while that of as-sprayed coating almost keeps intact besides a few cracks. Therefore, the oxidation resistance of as-sprayed coating is better than that of the polished one.
Key words: NiCrAlY coating; surface state; high-temperature oxidation; oxide film
