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采用电弧离子镀技术在铸造Ni基高温合金K17上沉积NiCrAlY涂层 ,测定了K17合金和NiCrAlY涂层在90 0℃～ 110 0℃的氧化动力学曲线 .实验结果表明 :K17合金和NiCrAlY涂层在不同温度静态空气中氧化动力学曲线基本符合抛物线规律 .90 0℃和 10 0 0℃时 ,K17合金上沉积NiCrAlY涂层后 ,明显改善了合金的抗氧化性 .110 0℃时 ,涂层的保护作用不如 90 0℃和 10 0 0℃ .90 0℃氧化时 ,NiCrAlY涂层氧化膜由α -Al2 O3 和Cr2 O3 组成 ;10 0 0℃氧化时 ,氧化初期 ,NiO、Cr2 O3 和Al2 O33种氧化物同时生成 .随着氧化的进行 ,不仅氧化膜增厚 ,而且发生较复杂的反应 ,氧化膜的相组成发生变化 .随着氧化温度升高 ,涂层和基体之间元素扩散加剧 ,Ti从基体扩散到涂层表面形成氧化物是导致涂层抗氧化性降低的原因之一 .氧化膜从涂层上剥落下来 ,也导致了涂层抗氧化能力降低
The NiCrAlY coating was deposited on cast Ni-base superalloy K17 by arc ion plating and the oxidation kinetics curves of K17 alloy and NiCrAlY coating at 90 0 ℃ ~ 110 0 ℃ were measured.The experimental results show that K17 alloy and NiCrAlY coating The kinetic curves of oxidation kinetics in static air at different temperatures basically accord with the law of parabola. When the NiCrAlY coating was deposited on K17 alloy at 90 0 ℃ and 100 ℃, the oxidation resistance of the alloy was obviously improved. At 110 ℃, the coating Is less protective than 90 0 ℃ and 100 ℃ .The oxidation of NiCrAlY coating is composed of α -Al 2 O 3 and Cr 2 O 3 when oxidized at 90 ℃. At the initial oxidation stage, NiO, Cr 2 O 3 and Al 2 O33 kinds of oxides are formed at the same time.With the progress of oxidation, not only the oxide film is thickened, but also complex reactions occur, the phase composition of the oxide film changes.As the oxidation temperature increases, the elemental diffusion between the coating and the matrix aggravates , Ti diffusion from the substrate to the surface of the coating oxide formation is one of the reasons leading to reduced oxidation resistance of the coating.Exfoliating the oxide film from the coating also results in a decrease of the antioxidant capacity of the coating