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    周宏明, 易丹青. 低压等离子喷涂NiCoCrAlYTa涂层的高温氧化行为[J]. 机械工程材料, 2009, 33(5): 18-21.
    引用本文: 周宏明, 易丹青. 低压等离子喷涂NiCoCrAlYTa涂层的高温氧化行为[J]. 机械工程材料, 2009, 33(5): 18-21.
    shu
    ZHOU Hong-ming, YI Dan-qing. High-temperature Oxidation Behavior of Low-pressure Plasma Sprayed NiCoCrAlYTa Coatings[J]. Materials and Mechanical Engineering, 2009, 33(5): 18-21.
    Citation: ZHOU Hong-ming, YI Dan-qing. High-temperature Oxidation Behavior of Low-pressure Plasma Sprayed NiCoCrAlYTa Coatings[J]. Materials and Mechanical Engineering, 2009, 33(5): 18-21.
    shu

    低压等离子喷涂NiCoCrAlYTa涂层的高温氧化行为

    High-temperature Oxidation Behavior of Low-pressure Plasma Sprayed NiCoCrAlYTa Coatings

      摘要
    • 摘要: 采用低压等离子喷涂技术在钴基高温合金K640表面制备了NiCoCrAlYTa合金涂层,利用XRD、SEM和EDS等研究了涂层的高温氧化行为.结果表明:该涂层在900 ℃的恒温氧化动力学曲线符合抛物线规律,氧化速率常数Kp为0.33×10-6 mg2·cm-4·s-1;温度为1 050 ℃时,氧化初期的Kp值约为1.95×10-6 mg2·cm-4·s-1,随着氧化时间的延长,氧化速率迅速降低;涂层在氧化过程中,表面先形成θ-Al2O3,随着氧化时间的延长,θ-Al2O3向α-Al2O3转变,且氧化温度越高转变速率越快,900 ℃氧化120 h后涂层表面仍存在θ-Al2O3,而1 050 ℃氧化10 h后θ-Al2O3就已基本完全转变;氧化过程中,基体与涂层之间发生互扩散;氧化后涂层中析出白色的颗粒状富钽相.

       

      Abstract: The NiCoCrAlYTa coatings were deposited on Co-based high-temperature alloy (K640) substrate by low-pressure plasma spraying(LPPS).The oxidation behavior of NiCoCrAlYTa coatings was evaluated by means of XRD,SEM and EDS.The results show that oxidation kinetic curves of the coating at 900 ℃ obeyed the parabolic law and the oxidation rate constant at 900 ℃ was 0.33×10-6 mg2·cm-4·s-1.The initial oxidation rate constant of the coating at 1 050 ℃ was 1.95×10-6 mg2·cm-4·s-1,and with the increase of oxidation time,the oxidation rate was decreased clearly.θ-Al2O3 was formed on the coating surface at the initial stage of oxidation.With the increase of oxidation time,θ-Al2O3 was transformed into α-Al2O3 and the transformation rate increased with the increase of oxidation temperature.There was still θ-Al2O3 on the coating surface oxidized at 900 ℃ for 120 h.The transformation of θ-Al2O3 into α-Al2O3 was observed after the coating was oxidized at 1 050 ℃ for 10 h.Interdiffusion of elements between Co-based alloy and the NiCoCrAlYTa coating was observed during the oxidation process.White Ta-rich precipitates were observed during the oxidation process.

       

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