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研究了溅射Co-30Cr-6Al-0.5Y及Ni-30Cr-6Al-0.5Y涂层对TiAl金属间化合物抗高温氧化性能的影响。结果表明,在900℃～1000℃范围内,CoCrAlY、NiCrAlY涂层表面由于可形成粘附性良好的A1_2O_3膜,大大改善TiAl金属间化合物的抗氧化性能。在氧化过程中,CoCrAlY、NiCrAlY涂层中的Co、Ni向基体中扩散,从而在基体一侧形成两个扩散层,其中扩散层的外层分别为硬而脆的A1Co_2Ti、AlNi_2Ti三元金属间化合物。1000℃氧化时,CoCrAlY涂层中普遍存在的柱状晶结构和瘤状缺陷,导致Ti向外扩散,涂层表面出现TiO_2。而NiCrAlY涂层表面900℃氧化即出现少量TiO_2。
The effects of sputtered Co-30Cr-6Al-0.5Y and Ni-30Cr-6Al-0.5Y coatings on the high-temperature oxidation resistance of TiAl intermetallics were investigated. The results show that the surface of CoCrAlY and NiCrAlY coating can improve the oxidation resistance of TiAl intermetallic compounds by forming A1_2O_3 film with good adhesion in the range of 900 ℃ ~ 1000 ℃. In the oxidation process, Co and Ni in the CoCrAlY and NiCrAlY coatings diffuse into the matrix, forming two diffusion layers on one side of the matrix. The outer layers of the diffusion layers are hard and brittle AlCo_2Ti and AlNi_2Ti ternary metal Compound. At 1000 ℃, columnar crystal structure and nodular defects are common in CoCrAlY coatings, resulting in the outward diffusion of Ti and the appearance of TiO_2 on the coating surface. However, a small amount of TiO 2 appears on the surface of NiCrAlY coating at 900 ℃.