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在镍基铸造高温合金K38G上采用脉冲电镀的方法沉积Pt镀层,通过分步加热粉末包埋渗Al处理后,获得表层为单相PtAl2,内层为β-NiAl的Pt-Al涂层.分别对单相PtAl2涂层进行1100℃静态氧化及循环氧化测试,并分析涂层在2种氧化条件下的氧化行为及失效机制.结果表明,单相PtAl2涂层表现出良好的抗静态氧化能力,初期快速增重主要来自于θ-Al2O3的生成,很快θ-Al2O3转变为α-Al2O3且增重趋于平缓.但是,单相PtAl2涂层的抗循环氧化能力较差,循环氧化过程中产生的热应力会导致部分区域PtAl2层剥离或脱落,继而引发涂层过早失效.因此,单相PtAl2涂层不适用于高温负载服役环境,其在循环氧化过程中的失效和退化主要来自于PtAl2层剥落以及剥落区附近β-NiAl层Al元素的快速消耗.
The Pt plating was deposited on the nickel-based superalloy K38G by pulsed electroplating, and the Pt-Al coating with single-phase PtAl2 in the surface and β-NiAl in the inner layer Single phase PtAl2 coatings were subjected to static oxidation and cyclic oxidation at 1100 ℃ and the oxidation behavior and failure mechanism of the coatings were analyzed under two oxidation conditions.The results showed that the single-phase PtAl2 coatings exhibited good static oxidation resistance, The initial rapid weight gain mainly comes from the formation of θ-Al2O3, and soon the θ-Al2O3 is transformed into α-Al2O3 and the weight gain tends to be gentle. However, the single-phase PtAl2 coating has poor cyclic oxidation resistance, Of the thermal stress will lead to partial area of the PtAl2 layer peeling off or peeling off and then lead to premature failure of the coating.Therefore, the single-phase PtAl2 coating is not suitable for high temperature load service environment, its failure and degradation in the cyclic oxidation mainly comes from PtAl2 Layer exfoliation and exfoliation of β-NiAl near the rapid depletion of Al elements.