EB-PVD制备TiAl/NiCoCrAl微层板复合材料氧化性能研究

Study on Oxidation Property of TiAl/NiCoCrAl Microlaminated Sheet Prepared by EB-PVD

摘要:

采用电子束物理气相沉积( EB-PVD)技术制备了TiAl/NiCoCrAl微层板复合材料，并对其在850 ℃空气条件下的抗氧化性能进行了研究，利用XRD和SEM对试样进行相组成和微观结构进行分析。结果表明：TiAl/NiCoCrAl微层板具有较好的抗氧化性能，其恒温氧化动力学曲线均近似符合抛物线规律。而TiAl/NiCoCrAl微层板的高温氧化机制为：表层的Al首先氧化生成多孔结构的Al2O3单层膜；随后内部TiAl层中的Ti元素穿越NiCoCrAl层到达表面生成(TiO2 + Al2O3)的氧化层；最后NiCoCrAl层中的Ni和Cr会形成以Cr2O3和NiCr2O4相为主的致密的外层氧化膜，这是其抗氧化性能显著提高的根本原因。

Abstract:

TiAl/NiCoCrAl microlaminated sheet prepared by EB-PVD have been oxygenized in air at 850 oC, and its oxidation property has been studied. The phase composition and microstructure have been analyzed by XRD and SEM. The results show TiAl/NiCoCrAl microlaminated sheet has good oxidation resistance and the oxidation kinetics curves follow the parabolic law. The oxidation mechanisms of TiAl/NiCoCrAl microlaminated sheet at high temperature is that Al on the surface will generate the Al2O3 monolayer oxide film with porous structure firstly, subsequently some Ti element in the inner TiAl layers will cross over the NiCoCrAl layers and reach the surface to generate the (TiO2 + Al2O3) oxide layer, and finally Ni and Cr in the NiCoCrAl layers can generate compact outer oxide film composed of Cr2O3 and NiCr2O4 phase, which is the essential reason why the oxidation resistance of the sheet increases obviously.