Y2O3对NiCr-Cr3C2金属陶瓷涂层热腐蚀性能影响行为研究

本文利用超音速火焰喷涂技术(HVOF),在20G钢表面制备了掺杂1wt.%、3wt.%、5wt.%三种不同含量Y2O3的NiCr-Cr3C2金属陶瓷复合涂层,并探究了其在650℃,Na2SO4/K2SO4熔盐环境中的热腐蚀性能。利用扫描电镜(SEM)、显微硬度计、拉伸试验机等对涂层的微观结构和力学性能进行了表征,利用X射线衍射仪(XRD)、拉曼光谱、X射线能谱仪(EDS)对复合涂层热腐蚀产物形貌、物相进行分析。结果表明掺杂1wt.%Y2O3的NiCr-Cr3C2复合涂层结构致密、孔隙率低、结合强度高,显微硬度达到801HV。热腐蚀过程中掺杂Y2O3的NiCr-Cr3C2复合涂层表面均生成耐蚀性良好且致密的Cr2O3膜。随着Y2O3掺杂量的增加,涂层的耐热腐蚀性能先升高后下降,当Y2O3掺杂量为1wt.%时,复合涂层表现出最佳的耐热腐蚀性能。

Effect of Y2O3 on Hot Corrosion Properties of NiCr-Cr3C2 Metal Ceramic Coatings

In this paper,the NiCr-Cr3C2 composite coatings doped with 1wt.%,3wt.%,5 wt.%Y2O3 were prepared on 20G boiler steel by high velocity oxygen fuel(HVOF)spray technology.The hot corrosion properties were investigated under molten salt mixture Na2SO4 and K2SO4 at 650℃.The micro-structure and mechanical properties were measured by scanning electron microscope(SEM),microhardness tester and tensile testing machine.The morphology and phase of hot corrosion products of composite coatings were analyzed by X-ray diffractometer(XRD),Raman spectroscopy and X-ray energy dispersive spectroscopy(EDS).The results show that the NiCr-Cr3C2 composite coating doped with 1wt.%Y2O3 has dense structure,low porosity,high bonding strength and microhardness up to 801 HV.In the process of hot corrosion,Cr2O3 film with good corrosion resistance and dense structure was formed on the surface of NiCr-Cr3C2 composite coatings doped with Y2O3.With the increase of Y2O3 doping content,the hot corrosion resistance of the coating increases first and then decreases.The composite coating doped with 1wt.%Y2O3 showed the best hot corrosion resistance.