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在热障涂层粘结层用CoNiCrAl Y合金中添加适量活性元素Ce和合金元素Re,1000℃空气气氛下进行恒温氧化,测试合金氧化动力学,采用X射线衍射(XRD)、扫描电镜/能谱(SEM/EDS)等手段观测氧化产物的物相组成和转变、氧化膜结构,进而比较添加适量活性元素Ce和合金元素Re对合金氧化行为的影响。结果表明,当前氧化条件下,合金氧化动力学可以划分为两个阶段:氧化初期,氧化速率较快;稳定氧化阶段,氧化产物由亚稳态θ-Al2O3转化成稳态α-Al2O3,氧化速率明显降低。CoNiCrAl Y合金表面形成了单一Al2O3膜,而CoNiCrAl YRe合金生成了富Cr氧化物外层+Al_2O_3内层双层氧化膜,并且在贫铝区形成了少量内氮化物。0.1%Ce(质量分数)的加入促进了Al的选择性氧化,加快了Al2O3的相转变,从而促进保护性α-Al2O3氧化膜的更快形成,使得CoNiCrAl Y合金稳定氧化阶段氧化速率常数由3.3×10~(-13)g~2·cm~(-4)·s~(-1)降低为1.5×10~(-13)g~2·cm~(-4)·s~(-1)。而且,Ce和Re元素共同存在时对合金抗氧化性能的改善效果更显著,CoNiCrAl YRe Ce合金表面形成了单一、连续、致密的Al_2O_3保护膜,Ce的加入使得含Re合金CoNiCrAl YRe的稳定氧化阶段氧化速率常数由2.8×10~(-13)g~2·cm~(-4)·s~(-1)降低为7.5×10~(-14)g~2·cm~(-4)·s~(-1)。
CoNiCrAlY alloy with thermal barrier coating was coated with proper amount of active elements Ce and alloying elements Re and was oxidized at 1000 ℃ in air at constant temperature. The oxidation kinetics of the alloy was tested by X-ray diffraction (XRD), scanning electron microscopy (SEM / EDS) and other means to observe the phase composition and transformation of the oxide product, the oxide film structure, and then compare the effect of adding appropriate amount of active elements Ce and alloying elements Re on the oxidation behavior of the alloy. The results show that under the current oxidation conditions, the oxidation kinetics of the alloy can be divided into two stages: the initial oxidation stage, the oxidation rate is relatively fast; in the steady oxidation stage, the oxidation products are transformed from the metastable θ-Al2O3 to the steady α-Al2O3, the oxidation rate Obvious reduction. A single Al 2 O 3 film was formed on the surface of CoNiCrAlY alloy, while the CoNiCrAlYRe alloy formed a Cr-rich oxide + Al_2O_3 double layer oxide film and formed a small amount of nitrides in the lean zone. The addition of 0.1% Ce promotes the selective oxidation of Al and accelerates the phase transformation of Al 2 O 3 so as to accelerate the formation of the protective α-Al 2 O 3 oxide film faster, and the oxidation rate constant of CoNiCrAl Y alloy during steady oxidation is increased from 3.3 × 10 ~ (-13) g ~ 2 · cm ~ (-4) · s ~ (-1) decreased to 1.5 × 10 ~ (-3) g ~ 2 · cm ~ (4) · s -1 ). Moreover, the co-presence of Ce and Re improves the anti-oxidation performance of the alloy. A single, continuous and dense Al 2 O 3 protective film is formed on the surface of CoNiCrAl YRe Ce alloy. The addition of Ce results in stable oxidation of CoNiCrAl YRe containing Re The oxidation rate constant decreased from 2.8 × 10 ~ (-13) g ~ 2 · cm ~ (-4) · s -1 to 7.5 × 10 ~ (-14) g ~ 2 · cm ~ (-4) · s ~ (-1).