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冲蚀角对超音速火焰喷涂Cr3C2-NiCr涂层冲蚀磨损行为的影响

Effect of impingement angle on erosion wear behavior of HVOF Cr3C2-NiCr coating

  • 摘要: 采用超音速火焰喷涂(high-velocity oxygen-fuel, HVOF)技术,在1Cr18Ni9Ti不锈钢表面制备Cr3C2-NiCr金属陶瓷复合涂层. 研究了涂层的显微组织、相组成以及涂层和不锈钢的冲蚀行为和机理,探讨了冲蚀角与耐冲蚀性能的关系规律. 结果表明,涂层组织结构致密均匀,主要由Cr3C2以及少量的Cr7C3, Cr23C6和(Ni, Cr)固溶体相组成. Cr3C2-NiCr涂层的耐冲蚀性能随着冲蚀角的增大而减小,在低冲蚀角下涂层的破坏形式主要为微切削,重量损失较低,表现出优异的耐冲蚀性能. 随着冲蚀角的增大,冲蚀沙粒对涂层产生垂直冲击作用,粘结相与硬质相之间产生裂纹导致粘结相脱落,硬质相失去粘结相的支撑作用而裸露出来,在冲蚀沙粒的持续攻击下剥落,形成许多小冲蚀坑. 随着剥落硬质相数量的增加,小冲蚀坑逐步发展为大冲蚀坑,重量损失较大,耐冲蚀性能较差.

     

    Abstract: High-velocity oxygen-fuel (HVOF) technology was adopted to prepare a Cr3C2-NiCr cermet composite coating on the surface of 1Cr18Ni9Ti stainless steel. The microstructure, phase composition and erosion of the coating and stainless steel, the relationship between impingement angle and erosion resistance were studied. The results show that the coating structure is compact and uniform, mainly composed of Cr3C2 and a small amount of Cr7C3, Cr23C6 and (Ni, Cr) solid solution phases. The erosion resistance of the Cr3C2 -NiCr coating decreases with the increase of the impingement angle. At low impingement angles, the damage of the coating is mainly micro-cutting, and the weight loss is low, showing excellent erosion resistance. As the impingement angle increases, the erosion sand particles have a vertical impact on the coating, cracks between the binder phase and the hard phase cause the adhesion phase to fall off, thus the hard phase loses the support of the binder phase and is exposed, peeling off under the continuous attack of erosive sand, forming many small erosion pits. With the increase of the number of hard phases peeling off, small erosion pits gradually develop into large erosion pits, with greater weight loss and poor erosion resistance.

     

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