铝硅涂层在1050℃下混合硫酸盐中的热腐蚀行为  

Hot corrosion behavior of Al-Si coating in mixed sulphate at 1050 ℃

作　　者：王宏宇[1] 崔万里[1] 袁晓明[1] 赵前[1] 汪涵[1] 

机构地区：[1]江苏大学机械工程学院,江苏镇江212013

出　　处：《材料热处理学报》2016年第11期140-145,共6页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51405204)

摘　　要：采用粉末共渗法在镍基高温合金表面获得约为300μm厚的铝硅涂层,考察了其在1050℃下混合硫酸盐（Na2SO4＋25%K2SO4）中的热腐蚀行为,较为系统地研究了其热腐蚀动力学行为及其机制、熔盐作用下氧化膜的生长与破坏过程和热腐蚀不同时间后的腐蚀产物等。结果表明,相对于已有铝硅涂层在高温条件下（850~980℃）热腐蚀的相关研究,其在1050℃超高温下混合硫酸盐中的热腐蚀更加严重,这与超高温下熔盐对保护性氧化膜的熔解作用更强密切相关。在本实验条件下,铝硅涂层在1050℃下混合硫酸盐中热腐蚀70 h后已趋于失效,当热腐蚀90 h时其腐蚀层深度已达约75μm;此时,不仅涂层中Al和Ni直接与熔盐相互作用,而且Cr、Si也参与了与熔盐的反应,同时高温合金基体中的Ti也已扩散至表面。Al-Si coatings with thickness of about 300 μm on a Ni-based superalloy were prepared by powder co-penetration. Hot corrosion behavior of the Al-Si coatings in Na2SO4-25% K2SO4 mixed sulphate at 1050 ℃ were investigated,which includs the hot corrosion kinetics and its mechanism,growth and destruction process of oxide film under the action of the molten sulphate and corrosion products after hot corrosion for different time. The results indicate that the hot corrosion of the Al-Si coatings in mixed sulphate is much more serious at ultrahigh temperature of 1050 ℃ comparing with that reported at 850-980 ℃ due to the stronger melting action of the molten sulphate to protective oxide film at the ultra-high temperature. Under the experimental condition in this work,the Al-Si coatings tend to be failure after hot corrosion in the mixed sulphate at 1050 ℃ for 70 h. When the hot corrosion time reaches 90 h,the corroded layer depth is about75 μm. In this case,not only Al,Ni of the coatings directly interacts with the molten sulphate,but also Cr,Si of the coatings participated in the reaction with the molten sulphate. Moreover,Ti in the superalloy substrate has also diffused to the surface of the Al-Si coatings.

关 键 词：金属粘结层 铝硅涂层 超高温热腐蚀 混合硫酸盐 热腐蚀行为 

分 类 号：TG174.44[金属学及工艺—金属表面处理]