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采用静态高温氧化、热腐蚀试验以及多种物理分析方法研究了镍基合金上的铝—硅涂层的防护性能。揭示了硅在涂层中的分布形式及其在高温曝置期间的变化情况。指出铝—硅涂层的防护性能明显优于渗铝涂层,而且在本试验范围内随硅含量的增加而提高。这是由于: (a) 铝—硅涂层减轻或防止涂层中“MC碳化物缺口”的出现; (b) 含硅的γ′-相具有优良的抗氧化性能; (c) 1100℃短时间曝置后在Al—Si涂层与基体界面处形成的连续的富硅M_6C“隔层”起扩散屏障的作用。
The protective properties of aluminum-silicon coatings on Ni-based alloys were investigated by static high temperature oxidation, hot corrosion tests and various physical analysis methods. Reveals the distribution of silicon in the coating and its change during high temperature exposure. It is pointed out that the protective properties of aluminum-silicon coatings are significantly better than that of aluminized coatings and increase with the increase of silicon content within the scope of this test. This is due to: (a) the aluminum-silicon coating reduces or prevents the appearance of “MC carbide nicks” in the coating; (b) the silicon-containing γ’-phase has excellent oxidation resistance; The continuous silicon-rich M_6C “barrier” formed at the interface between the Al-Si coating and the substrate after time exposure functions as a diffusion barrier.