NiAl(Si)+CeO_2型高温涂层氧化行为的研究

采用复合技术制备了含弥散CeO_2的NiAl(Si)型高温涂层,并同几种铝化物涂层的氧化行为进行了对比研究,重点考察了CeO_2及Si在改善涂层抗氧化性能方面各自的作用及其相互关系。涂层组织及成分分析表明,少量Si固溶于β-NiAl相中,大部分Si以第二相的形式主要弥散分布于涂层的内侧,且合金渗Al-Si涂层中的Si含量明显高于同类复合NiAl(Sj)+CeO_2涂层。氧化实验表明,Si及CeO_2可有效地降低涂层1100℃的氧化速率。Si对涂层抗循环氧化性能的改善作用不显著,而CeO_2则具有益作用,特

OXIDATION BEHAVIOUR OF NiAl(Si)+CeO_2 TYPE HIGH TEMPERATURE COATING

The oxidation behaviour of a NiAl(Si)-type high temperature coating with dispersed ceria prepared by a composite technique was compared with several kinds of aluminide or silicoaluminide coatings. The effect of ceria and silicon on the oxidation resistances of the coatings were studied emphatically. It was revealed that most of Si-rich secondary phases dispersed in the inner part of the coating and only a little Si solved in NiAI phase; in addition silicon content in silicoaluminizing coating on the alloy itself was much higher than that in the composite coating. The results of oxidation tests indicated that the oxidation rates of the coatings may be effectively reduced by adding ceria and silicon; the adhesion of scaie was improved markedly by the addition of ceria, especially by simultaneous addition of both ceria and silicon.