摘要
目的提高材料的高温抗氧化腐蚀性能。方法采用气相渗铝方法在K417镍基高温合金表面制备铝化物涂层,通过光学显微镜、扫描电子显微镜(SEM)和能谱(EDS)分析渗铝层厚度、显微组织形貌和各元素在渗层中的分布,分析温度和时间对镍基高温合金渗铝层的形成影响规律。结果气相渗铝方法制备的渗铝层组织为典型的外扩散型组织即外层是单一的β-NiAl相,内层是含富Cr析出相的扩散层,扩散层的细小析出相对Al元素的扩散起到阻碍作用。结论随着渗铝温度的提高和渗铝时间的延长,渗层厚度逐渐增加,且渗铝温度对渗层厚度的影响远高于渗铝时间对渗层深度的影响。渗铝温度临界值为980℃,低于该温度时厚度增长不显著,高于该温度时厚度对渗铝温度和时间的敏感性增加。此外,渗铝温度越高,渗铝层组织中形成孔洞的倾向越大。
Objective To improve high temperature oxidation resistance of materials.Methods The aluminide coating was prepared on the surface of K417 Ni-superalloy by gas-phase aluminizing.The thickness,microstructure and distribution of elements in the coating were analyzed by optical microscope,scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS).And the influences of temperature and time on the coatings forming rules were analyzed.Results The microstructure of the aluminized layer prepared by vapor-phase aluminizing method was a typical external diffusion structure.The outer layer was a single β-NiAl phase,and the inner layer was a diffusion layer containing Cr-rich precipitates.The fine precipitation of diffusion layer acted as a hindrance to the diffusion of Al element.Conclusion With the increase of aluminizing temperature and time,the thickness of aluminizing layer increases gradually,and the effect of aluminizing temperature on the thickness of aluminizing layer is much higher than that of aluminizing time on the depth of aluminizing layer.The critical value for aluminizing temperature is 980 ℃.The thickness increase was not significant under 980 ℃and the sensitivity of thickness to the aluminizing temperature and time increases when the temperature was higher than 980 ℃.In addition,the higher the aluminizing temperature,the greater the tendency to form pores in the aluminized layer.
作者
蒙彩思
火克莉
陈忠
张姚
郝粉利
MENG Cai-si;HUO Ke-li;CHEN Zhong;ZHANG Yao;HAO Fen-li(AECC Guiyang Precision Casting Company,Guiyang 550014,China)
出处
《装备环境工程》
CAS
2019年第1期13-16,共4页
Equipment Environmental Engineering
