真空热处理对冷喷涂Ni-Al2O3复合涂层组织与显微硬度的影响
Effect of Vacuum Heat Treatment on Microstructure and Microhardness of Ni-Al2O3 Composite Coating Prepared by Cold Spraying
刘 卫1, 余 敏2, 李文亚2
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作者单位：(1. 青海师范大学 物理系, 青海 西宁 810008; 2. 西北工业大学 摩擦焊接陕西省重点实验室, 陕西 西安 710072)
中文关键字：冷喷涂； 真空热处理； Ni-Al2O3复合涂层； 显微组织； 断口形貌
英文关键字：cold spraying; vacuum heat treatment; Ni-Al2O3 composite coating; microstructure; fracture morphology
中文摘要：采用冷喷涂制备了Ni-Al2O3复合涂层，并通过真空热处理改善了Ni-Al2O3复合涂层的组织与性能。 结果表明，后热处理可使涂层与基体发生冶金结合，同时热处理态涂层的孔洞缩小、层间裂纹间隙有闭合趋势，涂层更致密。但热处理对Al2O3颗粒的尺寸、分布及形貌几乎没有影响。同时热处理态涂层断口表现出韧性断裂特征，基体颗粒之间以及基体与增强体之间的结合增强。热处理后涂层硬度降低为(98.2±19.2) HV0.2，涂层韧性得到提高。
英文摘要：Ni-Al2O3 composite coating was deposited by cold spraying and its microstructure and properties were modified through post-spray vacuum heat-treatment. The results show that the metallurgical bonding between the coating and the substrate is formed after the heat treatment. Meanwhile, the pores and inter-lamellar cracks tend to be closed, which effectively improve the compactness of the coating. However, heat treatment has little effect on the size, morphologies and distribution of Al2O3 particles in the Ni matrix compared with the as-sprayed ones. Moreover, the fracture of the annealed composite coating reveals a ductile failure, which indicates that the adhesions among the matrix particles and between the matrix and the reinforcement are enhanced through the post-heat treatment. The microhardness of the annealed composite coating decreases to (98.2±19.2) HV0.2, the toughness of the coating is improved.