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制备了3类不同成分的等离子喷涂Ni Cr BSi涂层,利用截面大载荷划痕测试方法表征了涂层内聚结合强度,评价了涂层在油润滑条件下的滑动磨损行为,讨论了涂层内部残余应力、显微硬度、内聚强度与涂层耐磨性之间的内在关联.结果表明:在本文所用涂层沉积与划痕测试条件下,Ni Cr BSi涂层内聚强度的高低次序为Ni25>Ni35>Ni45,涂层显微硬度的高低次序与喷涂原始粉末硬度次序同为Ni25Ni35>Ni45;Ni Cr BSi涂层在低载荷条件下的磨损失效形式主要为磨粒磨损,随着载荷增加,涂层内部微小孔隙、裂纹等缺陷在残余拉应力和摩擦剪切力作用下诱发裂纹扩展并引发材料剥落,使疲劳剥落主导了涂层的磨损失效.
Three types of plasma-sprayed Ni-Cr BSi coatings with different compositions were prepared. The cohesive strength of the coating was characterized by the large-area scratch test method. The sliding wear behavior of the coating under oil-lubricated condition was evaluated. Internal residual stress, microhardness, cohesive strength and wear resistance of the coating.The results show that in the coating deposition and scratch test conditions used in this article, Ni Cr BSi coating cohesive strength of high and low order Ni35> Ni35> Ni45, the order of microhardness of coating is the same as that of Ni25 Ni35> Ni45. Wear and tear of Ni Cr BSi coatings under low load is mainly abrasive wear. With the increase of load, tiny pores and cracks Such defects as residual tensile stress and frictional shear force induced crack propagation and lead to material spalling, so fatigue spalling dominates the coating wear failure.