高溫氧化行為的影響
(中國科學(xué)院 金屬研究所， 沈陽 110016)
摘 要: 將原始噴涂態(tài)和表面拋光態(tài)的NiCrAlY涂層在1050℃恒溫氧化300h， 利用XRD, SEM, EDS方法， 測定涂層的氧化物及其相轉(zhuǎn)變， 分析表面氧化膜的生長破壞行為。 結(jié)果表明: 兩種涂層在1050℃保溫， 在150h以內(nèi)均能生成α-Al2O3氧化膜； 150h后， 拋光態(tài)涂層保護(hù)性氧化膜被破壞， 抗氧化能力下降， 噴涂態(tài)涂層表面粗糙， 連續(xù)Al2O3保護(hù)膜的形成較晚， 氧化早期氧化膜中存在微裂紋， 可釋放應(yīng)力， 有利于氧化膜與涂層的結(jié)合。 氧化動力學(xué)曲線符合拋物線規(guī)律， 氧化至300h， 表面氧化膜只有少量微裂紋， 無剝落。 說明噴涂態(tài)涂層的長期恒溫抗氧化能力比拋光態(tài)涂層強(qiáng)。
關(guān)鍵字: NiCrAlY涂層； 表面狀態(tài)； 高溫氧化； 氧化膜
on its high-temperature oxidation behavior
GUAN Heng-rong, HU Zhuang-qi
（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
