稀土Y对ASISI430不锈钢抗高温氧化性能影响的研究

本工作通过离子注入的方式，在AISI430合金表面注入不同剂量的稀土Y进行改性，研究了不同剂量的稀土Y对合金高温抗氧化性的影响。采用X射线衍射仪（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、光电子能谱仪（XPS）分析氧化膜的物相构成、微观组织形貌、稀土Y的化学形态，并通过VL200DX超高温激光共聚焦显微镜对氧化过程进行原位观察。结果表明：合金表面注入稀土Y剂量为6×1017ions/cm2具有最佳抗氧化性和抗剥落性，相比原始试样，单位面积增重量以及剥落量分别减少了43.7%， 78.4%。合金表面注入Y优先氧化为Y2O3，一方面促进氧化膜的形成，另一方面抑制了晶粒长大。此外，晶界处Y2O3阻碍了金属阳离子通过晶界向外扩散。重要地，部分Y取代了MnCr2O4尖晶石中Mn2+、Cr3+占位，产生空穴缺陷，缓解了氧化层内应力，减少裂纹和孔洞的产生，使氧化层与基体结合紧密。

Effect of Rare Earth Y on High Temperature Oxidation Resistance of AISI430 Stainless Steel

In this work, to study the effect of Y on the high temperature oxidation resistance of alloy, different doses of rare earth Y were implanted on the surface of alloy by means of ion implantation. The characteristics of oxide scales were investigated by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) methods. The oxidation process was observed in situ by VL200DX ultra high temperature confocal laser scanning microscope. The results show that the weight gain per unit area and the amount of spalling of Y-implanted samples reduced by 39.4% and 77.8% respectively, compared with the un-implanted Y samples. Y irons on the alloy surface were oxidized to Y2O3 preferentially, which promotes the formation of oxide film and inhibits the grain growth. In addition, Y2O3 at the grain boundary hinders the diffusion of metal cations through the grain boundary. Importantly, Y substituted for Mn2+and Cr3+ in MnCr2O4 spine, resulting in the information of vacancy defect. It relieve the internal stress of oxide layer and reduce the generation of cracks and holes that make oxide layer bond with the matrix closely.