K4104高温合金Al-Si涂层耐腐蚀性能研究

Research on corrosion resistance of an Al-Si coating on a K4104 high-temperature alloy

为提高航空发动机叶片抗高温氧化性能,通过热扩散的方法,在K4104镍基高温合金表面制备了铝化物Al-Si涂层,经1 000℃×200 h高温腐蚀氧化性能试验.利用扫描电子显微镜及能谱对涂层进行了表层形貌、截面组织形态观察及成分测试.试验结果表明,K4104镍基高温合金表面Al-Si涂层在长时间的高温氧化过程中已转变成完整致密的-αAl2O3氧化层和富铝的-βNiAl和富镍的-βNiAl化合物层,且与基体合金的粘附性良好.改性的铝化物涂层中Si元素的适量加入和合理分布能有效地抑制β相的生长,促进M6C型碳化物的形成,固结了W、Mo等元素,延长涂层的退化速度,使涂层获得更佳的抗高温腐蚀氧化性能.

In order to improve the high temperature corrosion performance of aero-engine blades, the Al-Si coating of a K4104 superalloy was prepared by the thermal diffusion method. After high temperature corrosion and oxidation experiments at 1 000 ℃ for 200 hrs, surface morphology, cross-sectional micrography and chemical composition testing of the Al-Si coating were done using SEM and EDS. Experimental results indicated that the Al-Si coating is transformed into three layers of α-Al2O3, Al-rich β-NiAl and Ni-rich β- NiAl, all of which have good adhesiveness with the basal body. The proper adding of Si and its reasonable distribution in the modified aluminum coating plays a significant role in suppressing the growth of the β- NiAl phase, accelerates the formation of M6C, puts a stay on the activity of elements of W and Mo , delays the degradation of the coating and gives the coating better corrosion and oxidation resistance at high temperatures.