Oxidation behaviors of electrodeposited nickel-cobalt coatings in air at 960°C  

电沉积Ni-Co涂层在960°C空气中的氧化行为(英文)

作　　者：周科朝[1] 马莉[1] 李志友[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《Transactions of Nonferrous Metals Society of China》2011年第5期1052-1060,共9页中国有色金属学报（英文版）

基　　金：Project (2005CB623703) supported by the National Basic Research Program of China; Project (50474051) supported by the National Natural Science Foundation of China; Project (CX2009B032) supported by Innovation Foundation for Postgraduate of Hunan Province, China; Project (ZKJ2008018) supported by the Precious Apparatus Open Share Foundation of Central South University, China; Project (2009ybfz02) supported by the Outstanding Doctoral Dissertation Support Foundation of Central South University, China

摘　　要：Ni coating and Ni-Co alloy coatings were produced by adjusting the composition of the plating solution using a direct current electrodepositing process. The oxidation behaviors of nickel and nickel-cobalt alloys in air at 960 ℃ were studied by thermogravimetric （TG） analyzer and then the formed oxide scales were examined by scanning electron microscopy/energy dispersive spectroscopy （SEM/EDS）, X-ray diffractometry （XRD）, and Raman spectroscopy. The scale morphologies, composition, grain size and mechanism of oxidation were discussed in detail. The results show that oxidation rates ofNi, Ni-7%Co （mass fraction） and Ni-15%Co generally follow parabolic relationship, whereas that of Ni-30% Co alloy follows cubic relationship. The higher the Co content of the alloys is, the faster the oxidation rate is. Metal concentration profiles reveal cobalt depletion in the alloy surface beneath oxide scales, and a progressive＇enrichment in cobalt towards the outer surface of the scale.采用直流电沉积工艺,通过调节电镀液的组成制备Ni涂层和Ni-Co合金涂层。采用热重(TG)分析金属Ni与Ni-Co合金在960°C下的氧化行为;采用SEM/EDS、XRD和Raman分析氧化膜的组成和结构。对氧化膜的形貌、组成、晶粒尺寸和氧化机制进行分析。结果表明:Ni金属、Ni-7%Co和Ni-15%Co合金中Ni的氧化速率遵循抛物线定律,而Ni-30%Co合金中Ni的氧化速率遵循三次方定律;合金中Co含量越高,Ni的氧化速率就越快。金属含量分析表明:位于氧化膜下方的合金中Co元素有缺失,而且在位于氧化膜外侧的地方Co元素逐渐聚集。

关 键 词：nickel-cobalt alloys ELECTRODEPOSITION high temperature oxidation 

分 类 号：TG174.4[金属学及工艺—金属表面处理]