激光熔覆MoSi2涂层的研究

本文用高能激光束熔覆MoSi_2粉末在45钢基体上制备了耐高温结构用涂层,用XRD、SEM、EDAX和显微硬度仪分别对熔覆层的组织结构和硬度进行了研究。试验结果表明,由于基体的稀释作用,涂层的相组成为FeMoSi、Fe_2Si和少量的Mo_5Si_3。涂层组织呈现典型的细小枝晶组织特征,枝晶为FeMosi领先相,枝晶间为FeMoSi和Fe_2Si两相共晶,组织中无孔隙和裂纹等缺陷存在。Mo,Si,Fe线扫描成分分布在涂层-基体界面处均缓慢过渡,基体与涂层发生互扩散,为冶金结合。涂层硬度可达HV_(0.5)845,基体硬度为180,涂层硬度比基体提高3.7倍。

Study on laser cladding MoSi2 coating

This present work manufactured the coating for resistance to high temperature and structural applications on the 45 steel substrate by cladding MoSi2 powders with the laser beam of high energy, and, investigated the microstruc-ture and hardness of clad coatings using XRD, SEM, EDAX and mic ohardometer respectively. The experimental results show that the phase constitution of coating is composed of FeMoSi, Fe2Si and a small amount of Mo5Si3 due to dilution of the substrate in the deposit. The microstructure of the coatings is characterized of typical fine dendrites. Dendrites are composed of FeMoSi primary phase, and interdendritic areas are two eutectic phases of FeMoSi and Fe2Si. There is no defects of pores, cracks etc in microstructures. All composition distributions of line scanning of Mo, Si, Fe in the interfaces between coating and substrate change gradually, the elements of coating and substrate diffuse each other, the coating and the substrate are bonded metallurgically. The value of hardness of coating reaches HV0.5 845, times larger than that of steel substrate (HV0.5180).