表面涂覆CeO_2对Co－40Cr合金氧化行为的影响  

Effect of Superficially Applied Ceria on Oxidation Behavior of Co 40Cr Alloy

作　　者：靳惠明[1] 彭晓[1] 李铁藩[1] 沈嘉年[1] 李美栓[1] 周龙江[1] 黄建宇[2] 

机构地区：[1]中科院金属腐蚀与防护研究所 [2]中科院金属研究所

出　　处：《中国稀土学报》1996年第4期316-320,共5页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金

摘　　要：研究了表面涂覆ＣｅＯ２对Ｃｏ４０Ｃｒ合金在１０００℃、空气中恒温氧化和循环氧化的影响。并用扫描电镜／能谱（ＳＥＭ／ＥＤＸＳ）、电子探针（ＥＰＭＡ）、高分辨电子显微镜（ＨＲＥＭ）等测试手段对氧化膜的形貌和成分进行了观察分析。此外，还用声发射（ＡＥ）方法对氧化膜在热应力作用下发生的开裂和剥落进行了监测。结果表明，涂覆ＣｅＯ２后极大地提高了合金的抗恒温氧化和抗循环氧化性能。研究表明，涂覆的ＣｅＯ２主要以细小颗粒的形式高度弥散存在于氧化膜的外表面，并且主要分布于氧化物晶界上，其中部分ＣｅＯ２以更加细小（１０～２０ｎｍ）的形式存在于Ｃｒ２Ｏ３晶粒内部。这些弥散分布的ＣｅＯ２颗粒改变了Ｃｒ２Ｏ３氧化膜的生长机制，通过阻碍Ｃｒ３＋阳离子向外扩散，降低了氧化膜的生长速率，细化了氧化膜的晶粒并提高了膜的高温塑性。he effect of superficially applied ceria on isothermal and cyclic oxidation behavior of Co 40Cr(wt%) alloy in air at 1000 ℃ has been investigated, SEM/EDXS、 EPMA、 HREM have been used to study the scale's composition and morphology. Acoustic emission technique has been used to study the cracking and spalling behavior of the scale formed on Co 40Cr alloy with and without ceria. It was found that superficially applied ceria greatly improved the alloy's anti oxidation properties. Results show that ceria exists in the scale mainly near the scale/gas interface. Most of ceria disperse at the Cr 2O 3 grain boundary, and some small ceria particles(less than 20 nm) exist inside the Cr 2O 3 grain. These dispersed ceria and small ceria particles inside Cr 2O 3 grain changed the Cr 2O 3 scale growing mechanism from predominant Cr 3+ cation diffusion to predominant O 2- anion diffusion, decreased the scale's growing speed, in the mean time, decreased the grain size of chromia scale. The decrease of the growth speed can reduce the growth stress of the scale, and the decrease of the grain size can increase the fluxibility of the scale at high temperature respectively. The Cr 2O 3 scale formed on Co 40Cr alloy with ceria has much slower growth speed and much better adhesion on the substrate than scale formed on Co 40Cr alloy without ceria.

关 键 词：铈 表面涂覆 铬锰合金 氧化 稀土元素 

分 类 号：TG144[一般工业技术—材料科学与工程] TG174.44[金属学及工艺—金属材料]