Nb/NbCr_2合金表面硅化物涂层的高温抗氧化性能  

High Temperature Oxidation Resistance of Silicide Coatings on Nb/NbCr_2 Alloy

作　　者：乔彦强[1] 李懋源 郭喜平[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《材料研究学报》2015年第6期410-416,共7页Chinese Journal of Materials Research

基　　金：国家自然科学基金51401166和51371145;陕西省自然科学基金2014JQ6215;凝固技术国家重点实验室西北工业大学自主研究课题116-QP-2014资助项目~~

摘　　要：用扩散渗法在Nb/NbCr2合金表面制备硅化物涂层,研究了基体合金和涂层在1250℃的氧化行为。结果表明:在Nb/NbCr2合金表面渗Si所得硅化物涂层由(Nb,Cr)Si2和(Cr,Nb)Si2两相组成,过渡层为(Nb,Cr)5Si3,涂层的生长动力学服从抛物线规律。基体合金在1250℃氧化形成的氧化膜为Nb2O5和CrNbO4交替分布的疏松组织,与基体有剥离现象。渗Si涂层在1250℃氧化形成的氧化膜较为致密完整,与残留涂层结合良好,为SiO2和CrNbO4混合氧化膜,改善了合金的高温抗氧化性能。Silicide coatings on Nb/NbCr2 alloy were prepared by pack cementation method. The oxidation behavior of the bare- and coated- alloy was examined by isothermal test at 1250 ℃ in static air.The results show that the silicide coatings are composed of(Nb, Cr)Si2and(Cr, Nb)Si2phases. There exist a transitional layer of(Nb, Cr)5Si3in between the main coating and substrate. The coating growth kinetics at 1250℃ fits to parabolic law. The oxidation of Nb/NbCr2 alloy resulted in alternate layers of Nb2O5 and Cr Nb O4 with porous structure, which was wrinkling even spalling off after oxidation. The scale formed on the silicide coating after oxidation at 1250℃ was mainly composed of Si O2 and Cr Nb O4. The scale was relatively dense and had a good bond with the residual coating, thus showing an excellent oxidation resistance.

关 键 词：材料失效与保护 Laves相Nb Cr2 扩散渗 硅化物涂层 抗氧化性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理]