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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。
TiAl / NiCoCrAl microlayer composite was prepared by electron beam physical vapor deposition (EB-PVD) technology. The oxidation resistance of TiAl / NiCoCrAl composite was studied at 850 ℃. The phase composition of the sample was characterized by XRD and SEM And microstructure analysis. The results show that TiAl / NiCoCrAl microlayers have good oxidation resistance, and their kinetic curves of oxidation at constant temperature approximate the parabolic law. The high-temperature oxidation mechanism of TiAl / NiCoCrAl microlayer plates is as follows: the Al of the surface layer is first oxidized to form a porous structure of Al 2 O 3 monolayer; Ti element in the inner TiAl layer then passes through the NiCoCrAl layer to reach the surface to form an oxide layer of (TiO 2 + Al 2 O 3) Finally, Ni and Cr in the NiCoCrAl layer form a dense outer oxide film mainly composed of Cr2O3 and NiCr2O4 phases, which is the fundamental reason why the oxidation resistance is significantly improved.