汽车用316L不锈钢激光/等离子喷涂Co-Cr3C2涂层组织与结合强度分析

为了提高汽车用316L不锈钢表面的机械强度,采用激光/等离子喷涂的方法制得Co-Cr3C2涂层,并与等离子喷涂层进行比较,试验测试分析了涂层的微观组织及沉积过程中的焰流形态。分析结果表明:采用等离子喷涂制得的涂层存在大量孔隙;利用激光/等离子喷涂制备的Co-Cr3C2涂层具有明显的冶金结合特征,涂层中的孔隙裂纹较少。以激光/等离子喷涂制备的Co-Cr3C2涂层孔隙率小于等离子喷涂层的,结合强度高。等离子喷涂形成了完全熔融、部分熔融以及没有熔融的3种颗粒;采用激光/等离子进行喷涂制得的涂层内没有产生尺寸较大的的未熔颗粒,达到了更好的铺展状态,形成了尺寸更小的晶粒,显著降低了涂层中的裂纹与孔洞数量,提高了涂层的表面硬度与耐磨性。

Microstructure and Bonding Strength of Laser/Plasma Spraying Co-Cr3C2 Coating on Automobile 316L Stainless Steel

In order to improve the mechanical strength of 316 L stainless steel for automobile,Co-Cr3C2 coating was prepared by laser/plasma spraying method,and compared with plasma spraying coating.The microstructure of the coating and the flame flow morphology during deposition were tested and analyzed experimentally.Results showed that there were many pores in the plasma spray coating.The Co-Cr3C2 coating prepared by laser/plasma spraying had obvious metallurgical bonding characteristics,and the porosity of Co-Cr3C2 coating prepared by laser/plasma spraying was lower than that of the plasma spray coating.Three kinds of particles were formed by plasma spraying:completely melt,partially melt and no melt.No larger unmelted particles were produced in the coating preparation by laser/plasma spraying,which achieved a better spreading state and formed smaller grains,significantly reducing the number of cracks and holes in the coating,and thus improving the surface hardness and abrasion resistance of the coating.