Initial oxidation of an electrodeposited Ni-Cr-Al nanocomposite
A novel Ni-6Cr-7Al (wt.%) nanocomposite was developed by co-electrodeposition of Ni with nanoparticles of Cr and Al from a sulphate bath.The as-deposited nanocomposite consisted of a nanocrystalline Ni matrix and dispersed second phase nanoparticles of Cr and Al.The initial oxidation of the nanocomposite at 900℃ in air was investigated by SEM/EDAX,AFM,TEM and XPS.For comparison,the initial oxidation of an arc-melted Ni-6Cr-7Al alloy was also studied.It was found that an Al-rich oxide scale with fine-grained structure formed on the nanocomposite,whereas a Ni-rich oxide scale with larger-grained structure formed on the alloy during oxidation for 5 minutes.The results indicated that the unique structure of the nanocomposite favored a quick formation of Al2O3 scale.The reason lies in three aspects:first,the numerous dispersed Cr and Al nanoparticles as well as abundant grain boundaries act as the easy nucleation sites of Al2O3 when oxidation starts,second,initially-formed Cr2O3 serve as the catalyst for the nucleation and growth of Al2O3,third,the abundant grain boundaries in the nanocrystalline Ni matrix,as short-circuitdiffusion path of Al to oxidation front,promote fast formation of Al2O3.
Initial oxidation co-elecrodeposition Ni-Cr-Al nanocomposite
Yang Xiuying
Polytechnique School of Shenyang Ligong University,1 Binhe Rd, Fushun, 113122,China; State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Rd., Shenyang, 110016, China
国际会议
上海
英文
166-166
2012-10-19（万方平台首次上网日期，不代表论文的发表时间）