不同工艺制备铁基非晶复合涂层组织与性能研究

Study on the microstructure and properties of Fe-based amorphous composite coatings by different processes

分别采用大功率光纤激光器与超音速等离子喷涂设备在45号钢基体表面制备Fe基非晶复合涂层。采用扫描电镜、显微硬度计、X射线衍射仪对熔覆层进行微观组织和成分的研究;并分析熔覆层的显微硬度和耐腐蚀性能。结果表明,激光熔覆涂层成型良好,无明显的孔隙、宏观裂纹等缺陷,熔覆层与基体之间为结合强度较高的冶金结合。超音速等离子喷涂涂层存在一定的气孔、微裂纹等缺陷,涂层与基体之间为机械结合,结合强度相对较弱。激光熔覆层组织为柱状晶、树枝晶和非晶共存组织。激光熔覆层内组织致密,且析出了Fe-Cr、(CrFe)7C3化合物等硬质相。超音速等离子喷涂涂层截面形貌为典型的层状结构,涂层的非晶含量明显高于激光熔覆涂层,但由于其内部的孔隙和微裂纹,使激光熔覆涂层耐腐蚀性能优于超音速等离子喷涂涂层。

Fe-based amorphous composite coatings were prepared on the surface of 45 steel substrate by high power fiber laser and supersonic plasma spraying equipment separately. The microstructure,microhardness and corrosion resistance of the cladding layer were analyzed by the scanning electron microscopy,microhardness tester and X-ray diffractometer. The results show that the laser cladding coating is well formed. No obvious defects,such as pores and cracks,were observed in the cladding layer. A good metallurgical bond is formed between the cladding layer and the substrate;the microstructure of cladding layer is columnar crystal,dendritic and amorphous coexisting structure. The coating by supersonic plasma spray has a high amorphous content. The mechanical bond between cladding layer and substrate is relatively weak. The defects,such as pores and microcracks,were observed in the coating. The microstructure of the laser cladding layer is dense,and Fe-Cr,(CrFe)7C3 compound is precipitated,which makes the hardness and corrosion resistance of the laser cladding coating much higher than that of the supersonic plasma spray coating.