渗铝涂层对Ni_3Al－Mo基合金高温氧化的防护作用及机理  

INVESTIGATION ON ALUMINIZED COATING ON DS Ni_3Al-Mo BASE ALLOY

作　　者：叶长江[1] 李铁藩[1] 张亚明[1] 毛晓禹 

机构地区：[1]中国科学院金属腐蚀与防护研究所腐蚀科学开放实验室,暨南大学物理系

出　　处：《中国腐蚀与防护学报》1995年第2期87-92,共6页Journal of Chinese Society For Corrosion and Protection

基　　金：国家863计划资助

摘　　要：采用高活度渗铝工艺在ＩＣ－６（Ｎｉ３Ａｌ－Ｍｏ基）合金表面获得内扩散型渗铝涂层，在氮气环境下对渗铝涂层进行扩散处理．利用光学显微镜、ＳＥＭ、ＥＰＭＡ、ＸＲＤ分析研究了涂层的成分及组织结构，测定表明，涂层中的钼以Ｍｏ３Ａｌ沉淀相的形式存在．等温氧化及循环氧化实验表明，渗铝涂层的抗高温氧化性能明显优于ＩＣ－６合金；保护性的Ａｌ２Ｏ３氧化膜阻止了钼的氧化物的形成，避免了ＩＣ－６合金在循环氧化中出现的ＮｉＭｏＯ４相的多晶型转变，显著改变了合金的抗循环氧化能力；涂层经１０００℃、３００ｈ等温氧化及１０００℃、１００ｈ循环氧化后，未出现β－ＮｉＡｌ相的分解，可认为涂层具有较强的保护作用。Ni3Al-Mo base alloy IC-6 was aluminized by high activity process and the specimen was subsequentlydiffusion treated under argon atmosphere. The microstructure and chemical composition of the coatingwas investigated by optical microscopy, XEM, EPMA and XRD. It was found that molybdenum in thecoating is present as a second phase Mo3Al. The oxidation resistance of IC-6 alloy was improved markedlyby the aluminizing coating. The protective oxide film of A12O3 prohibited the formation of molybdenumoxide. During the cyclic oxidation test, the aluminized IC-6 alloy showed improved oxidation resistancebecause of the absence of the polymorphic change of NiMoO4 phase. The dissociation of β-NiAl phase inthe aluminizing coating has not been observed after 300 hours under isothermal oxidation or 100 hoursunder cyclic oxidation in air at 1000℃. It can be concluded that the coating possesses good enoughprotective properties.

关 键 词：渗铝 Ni3Al-Mo 金属间化合物 高温氧化 

分 类 号：TG146.15[一般工业技术—材料科学与工程] TG172.82[金属学及工艺—金属材料]