Q345R板材表面冷喷涂Al-Zn涂层的组织及性能研究

目的 研究添加元素Zn含量的变化对涂层的显微组织、孔隙率、硬度及涂层-基体间界面结合强度等的影响规律.方法 采用冷喷涂技术在Q345R板材表面制备性能优良的纯Al和Al-Zn复合涂层,通过扫描电子显微镜对涂层的形貌进行分析,通过维氏显微硬度计对涂层的力学性能进行表征,并揭示涂层与基体间的界面结合机理.结果 冷喷涂纯Al...

Study on the Structure and Properties of Cold Sprayed Al-Zn Composite Coatings on Q345R Plate

The effects of Zn content on the microstructure, porosity, hardness and interfacial bonding strength between coating and substrate were studied. Pure Al and Al-Zn composite coatings with excellent properties were prepared on Q345R plate by cold spraying technology, the morphology of the coating was analyzed by scanning electron microscope, the mechanical properties of the coating were characterized by Vickers microhardness tester, and the interface bonding mechanism between the coating and the substrate was revealed.The results show that the bonding between pure Al and Al-Zn composite coatings with Q345R steel substrate is well, without obvious holes and cracks at the interface. With the increase of Zn content, the density and hardness of the composite coating increase gradually, and the interfacial bonding strength of pure Al and Al-20wt.%Zn composite coating is similar, and the failure fracture mode is typical interfacial adhesive fracture. With the increase of the Zn content, the interfacial bonding strength between the coating and the substrate increases gradually, the bonding strength of Al-40wt.% Zn composite coating is 35 MPa, and the fracture mode changes from adhesive fracture to the mixed failure mode of dominant interfacial adhesive fracture and auxiliary cohesive fracture of the coating. In conclusion, cold spraying, characterized by low temperature solid state deposition, can effectively avoid the adverse effects such as oxidation, phase transition, and thermal cracking caused by high temperature. In the deposition process, with the increase of the Zn content, the tamping effect on the coating is constantly strengthened, which improves the compactness and the mechanical properties of the coating.