THE EFFECTS OF YTTRIUM ION-IMPLANTATION ON THE OXIDATION OF NICKEL CHROMIUM-ALLOYS .2. OXIDATION OF YTTRIUM IMPLANTED NI-20CR

被引:22
作者
HAMPIKIAN, JM
POTTER, DI
机构
[1] UNIV CONNECTICUT,INST MAT SCI,STORRS,CT 06269
[2] UNIV CONNECTICUT,DEPT MET,STORRS,CT 06269
来源
OXIDATION OF METALS | 1992年 / 38卷 / 1-2期
关键词
OXIDATION; ION IMPLANTATION; YTTRIUM; AMORPHOUS;
D O I
10.1007/BF00665049
中图分类号
TF [冶金工业];
学科分类号
0806 ;
摘要
Yttrium ions were implanted into an alloy of nickel containing 20 wt.% chromium. The oxidation weight gains of the implanted alloy, as well as unimplanted Ni-20Cr, were measured in 1 atm. of oxygen at temperatures between 815-degrees-C and 1100-degrees-C. Though a yttrium fluence of 2 x 10(15) ions/cm2 increased the weight gained at a given time for the implanted alloy compared to the unimplanted alloy, a fluence of 7.5 x 10(16) ions/CM2 considerably retarded the oxidation process. This retardation was caused both by a reduction in the duration of transient oxidation and by a reduction in the rate of parabolic oxidation that follows the transient stage. Examination of oxidized specimens revealed that the higher fluence yttrium implantation caused an earlier formation of Cr2O3, thus shortening the time during which NiO forms and contributing to the reduced time and weight gain during transient oxidation. This accelerated formation of Cr2O3 is explained by reference to the yttrium-implantation-induced amorphous phase present on the alloys, the formation of small grains of nickel-chromium solid solution within this amorphous phase, and the presence of NiCr2O4 at the oxide/gas interface. Potential causes of the reduced rates of parabolic oxidation are also discussed.
引用
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页码:139 / 161
页数:23
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