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利用等离子喷涂技术制备了NiCrCoAlY粒子和涂层,研究了等离子喷涂过程中NiCrCoAlY粒子的氧化行为以及屏蔽气体对NiCrCoAlY涂层抗高温氧化性能的影响。结果表明,粒子在飞行过程中存在对流氧化和扩散氧化两种氧化机制,对NiCrCoAlY粒子来说,在距喷嘴55mm以内的射流中心处以对流氧化为主,在距离喷嘴55mm以外将以扩散氧化为主;除飞行中的氧化外,粒子在喷涂过程中还发生形成涂层后的氧化,NiCrCoAlY粒子以飞行中的氧化为主;添加屏蔽气体能减少喷涂过程中涂层的氧化,提高涂层的抗高温氧化性能。
NiCrCoAlY particles and coatings were prepared by plasma spraying. The oxidation behavior of NiCrCoAlY particles during plasma spraying and the effect of shielding gas on the oxidation resistance of NiCrCoAlY coatings were studied. The results show that the particles have two kinds of oxidation mechanisms, ie convective oxidation and diffusion oxidation. In the case of NiCrCoAlY particles, convection oxidation occurs mainly in the jet center within 55 mm from the jet nozzle, and diffusion diffusion is dominant at 55 mm away from the jet nozzle ; In addition to the oxidation in flight, the particles also undergo oxidation after coating formation during the spraying process. NiCrCoAlY particles mainly dominate the oxidation in flight; addition of a shielding gas can reduce the oxidation of the coating during spraying and increase the resistance of the coating High temperature oxidation performance.