利用热重分析(TGA)、扫描电镜、能谱分析、电子探针及X射线衍射等技术研究了离子注入1×10~17Y~+/cm~2对Ni30Cr定向凝固合金1000℃恒温氧化行为的影响。合金的横向和纵向虽具有不同的显微结构,但氧化行为相似。注入Y~+降低了合金的氧化速率约1～2倍,细化了氧化膜晶粒,抑制了晶界优先氧化及内氧化现象的发生,减少了界面空洞,增强了膜的粘附性。产生上述结果的原因在于注入Y~+改变了合金的氧化机制,未注Y~+合金的氧化膜主要靠铬向外扩散生长,注Y~+合金则主要靠氧向内扩散生长。
The influence of implanted yttrium at dose of 1 × 1017Y+/cm2 on the isothermal oxidation behavior of directionally solidified alloy Ni30Cr in air at 1000℃ was studied using TGA, SEM/EDAX, SEM/EPMA and XRD. The oxidation behavior of both transversal and longitidinal samples was similar despite of their difference in microstructure. Y+-implantation reduced the weight gain by a factor of 2-3 after 20h oxidation. A finer grain size scale formed on the Y+-implanted alloy. Preferred oxidation and internal oxidation along grain boundaries were eliminated and the formation and growth of interfacial voids were inhibited. Y+-implantation improvement might be due to the change of the growth mechanism of scale from predominant outward diffusion of cations to prevailing inward diffusion of anions.
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