不锈钢渗铝后的表面组织、成分及其耐熔锌腐蚀性能  

Microstructure and Resistance to Corrosion by Molten Zinc of Thermally Oxidized Aluminizing Coating on Stainless Steel

作　　者：王志洪[1] 王建华[2] 苏旭平[2] 尹付成[2] 

机构地区：[1]株洲职业技术学院机械工程系,湖南株洲412002 [2]湘潭大学机械工程学院,湖南湘潭411000

出　　处：《材料保护》2008年第11期11-13,共3页Materials Protection

摘　　要：由于液态锌的腐蚀,使在热镀锌生产线上的工作零件失效严重,严重阻碍了热镀锌行业的进一步发展。对此,研究了采用固体粉末包埋法对1Cr18Ni9Ti不锈钢进行渗铝,再采用热氧化的方法使渗铝层表面原位生长Al2O3薄膜。结果表明:渗铝层表面主要由FeAl相组成,渗铝层呈多层结构,分为渗层外层(约250μm)、过渡层(约为50μm)和渗层内层(约为300μm)。渗铝层表面铝的浓度较高,超过30%(质量分数),渗铝层发生选择性氧化,在表面生成一层均匀致密的Al2O3膜,所得膜的厚度约为20μm。通过大量试验得出,渗铝层具有良好的耐锌液腐蚀性能,可作为锌液与铁表面接触的良好隔离层。The mechanical parts used in hot-dipping pots and continuous galvanizing line are liable to serious failure due to erosion and corrosion of molten zinc, which is restricting the development of hot galvanizing industry. Thus 1Cr18Ni9Ti stainless steel was a-luminized by means of pack cementation, and the resulting aluminizingcoating was thermally oxidized to form Al2O3 film. The composition, structure and morphology of the thermally oxidized aluminizing coating were analyzed by means of scanning electron microscopy, while its resistance to molten zinc-induced corrosion was examined as well. Results indicated that the as-prepared aluminizinglayer was mainly composed of FeAl phase, and it had multilayer structure, i. e. , an outer layer of about 250 μm thick, a transitional layer of about 50 μm thick, and an innerlayer of about300 μm thick. The weight fraction of element Al in the as -prepared aluminizing layer was above 30%. After thermal oxidation,an even and compact Al2O3 layer of about 20 μm thick was generated on the surface of the aluminizing coating. The thermally oxidized aluminizing coating had good resistance to corrosion by molten zinc and could be a promising candidate to keep iron off molten zinc.

关 键 词：渗铝 不锈钢 组织 成分 耐熔锌腐蚀 性能 

分 类 号：TG174.445[金属学及工艺—金属表面处理]