等离子熔覆镍基涂层抗氧化性能的研究

Studies on Antioxidation Properties of Plasma Cladding Ni Composite Coatings

采用预置式等离子熔覆方法在45钢表面制得Ni60以及Ni60+WC复合涂层,借助扫描电镜、能谱和X-射线衍射仪研究涂层的抗高温氧化性能。结果表明,在氧化膜形成的初期,氧化速率主要由氧的内扩散所控制,在氧化膜形成的后期则以Cr3+的扩散为主;涂层氧化膜的主要成分为SiO2和Cr2O3,其中Ni60+WC涂层表面的氧化膜中还有少量尖晶石结构相NiCr2O4。涂层的抗氧化性由涂层的成分和组织共同决定,WC颗粒的加入对涂层的抗氧化性有所提高。

Ni60 and Ni60/WC coatings were prepared by plasma cladding method on substrate of 45# steel. High-temperature antioxidation properties of the composite coatings were investigated by means of SEM, EDS and XRD. The results showed that the oxidation rate was mainly controlled by 02- inner-diffu- sing in the initial oxidation stage while in the later stage the dominated diffusion was Cr3＋ The oxidation films of coatings were composed of SiO2 and Cr2O3 ,while a spot of NiCr2O4 spinel oxide could also be de- tected on the surface of Ni60 ＋ WC coatings. The antioxidation properties of the composite coatings were codetermined by both the chemical composition and phase structure. Adding of the WC powder could im- prove the high-temperature antioxidation properties of the coatings.