AlMg5及AlMg5-Zr电弧喷涂涂层的组织和性能研究

目的在铝镁涂层中加入微量的Zr元素,对AlMg5及AlMg5-Zr电弧喷涂涂层的组织和性能进行对比研究。方法采用体视显微镜观察涂层的表面形貌,采用拉伸试验机、维氏显微硬度计测量涂层的结合强度及表面硬度。通过海水浸泡试验和中性盐雾试验研究涂层的耐腐蚀性能,采用电位仪测量涂层在海水腐蚀过程中的腐蚀电位,采用SEM观察涂层经中性盐雾腐蚀后的表面微观形貌,采用失重法计算涂层的中性盐雾腐蚀速率。结果微量Zr元素的加入,改善了铝镁涂层的组织结构,降低了涂层的孔隙率。相比于AlMg5涂层,AlMg5-Zr涂层的结合强度及表面硬度分别提高了13.8%和10.8%。海水浸泡腐蚀过程中,AlMg5-Zr涂层的自腐蚀电位表现较正,发生腐蚀较难,浸泡2880 h后,AlMg5-Zr涂层表面失光变色较少。中性盐雾腐蚀过程中,AlMg5-Zr涂层的腐蚀速率较小,腐蚀1920 h后,AlMg5涂层的微观腐蚀痕迹较明显,表面疏松,且出现连续的白色腐蚀产物。结论 Al Mg5-Zr电弧喷涂涂层的组织结构、与基体的结合强度、表面显微硬度及耐腐蚀性能均优于AlMg5涂层。

Microstructures and Properties of AlMg5 and AlMg5-Zr Arc Spraying Coatings

The work aims to comparethe microstructures and properties of AlMg5 and AlMg5-Zr arc spraying coatings by adding a few Zr elements in AlMg coating. The surface morphologies of AlMg5 and AlMg5-Zr coatings were observed with a stereomicroscope. The adhesion strength and surface microhardness of the coatings were measured by a tensile tester and a Vickers hardness tester respectively. Corrosion resistance of the coatings was studied by seawater immersion test and salt spray test. SEM was utilized to investigate the corrosion morphologies of the coatings and a potentiometer was utilized to measure corrosion potential of the coatings. The microstructures of AlMg5 coating were improved and the porosity of AlMg5 coating was decreased by adding Zr. The adhesion strength and surface microhardness of AlMg5-Zr coating were 13.8% and 10.8% higher respectively than that of AlMg5 coating. Self-corrosion potential of AlMg5-Zr coating in seawater was higher than that of AlMg5 coating, and after immersion in seawater for 2880 hours, the surface morphologies of AlMg5-Zr coating changed a little. Salt spray corrosion rate of AlMg5-Zr coating was slower than that of AlMg5 coating, and after salt spray corrosion for 1920 hours, the corrosion marks on AlMg5 coating were more obvious than that on AlMg5-Zr coating, and there were continuous corrosion products appearing on AlMg5 coating surfaces. The microstructures and properties of AlMg5-Zr arcspraying coating, such as the adhesion between coating and substrate, surface microhardness and corrosion resistance are superior to that ofAlMg5 coating.