铝—硅涂层防护性能的研究

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。

High Temperature Performance of the Aluminium-silicon Coatings

The high temperature performance of the aluminium-silicon coated nickelbase superalloy K3 has been studied by static high-temperature oxidation test, hot-corrosion test and many physical analysis methods. The form of silicon distribution in the coating and its change during high-temperature exposure are revealed. The protective properties of the Al-Si coatings are evidently superior to aluminized coating and increase with silicon content for the following reasons. (a) The occurrence of "MC carbide notch" is diminished or prevented in Al-Si coatings. (b) The silicon-containing γ'-phases have a superior oxidation resistance. (c) A continuous Si-rich M(?)C "partition" formed at the interface between Al-Si coating and substrate after a short-time exposure at 1100℃ acts as a diffusion barrier.