等离子喷涂NiCrCoAlY涂层氧化控制研究

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55 mm以内的射流中心处以对流氧化为主，在距离喷嘴55 mm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

Oxidation Control of Plasma Sprayed NiCrCoAlY Coating

NiCrCoAlY particles and coatings were prepared by plasma spraying technique. The oxidation behavior of NiCrCoAlY particles in the plasma spraying process and the influence of shrouding gas on high-temperature oxidation resistance of NiCrCoAlY coatings were investigated. The results show that there are two oxidation mechanisms during in-flight oxidation. One is convective oxidation, and the other is diffusion oxidation. In the plasma?zone whose distance to the nozzle is less than 55 mm, convective oxidation is the dominating oxidation mechanism; in the zone whose distance to the nozzle is?more than 55 mm, diffusion oxidation is the principal mechanism. Besides the in-flight oxidation, the oxidation after spraying also occurs for the particles. In-flight oxidation is the main oxidation mechanism for NiCrCoAlY particles in plasma spraying. Shrouding gas can decrease the oxide content of in-flight oxidation and increase the oxidation resistance of NiCrCoAlY coatings