激光熔覆TiC增强不锈钢涂层的组织及性能

Microstructure and properties of laser cladding TiC reinforced stainless steel coatings

以机械混合后的2205不锈钢、钛铁和Cr3C2粉末为原料,在16Mn钢的表面制备了TiC增强不锈钢激光熔覆层,并对其显微组织、摩擦磨损及电化学腐蚀行为进行了研究。结果表明:熔覆层组织主要由α-Fe、γ-Fe和TiC析出相构成,Ti和C元素反应充分,无Cr3C2陶瓷相残留,也无其他杂相生成;随TiC比例的增加,γ-Fe相含量减少,TiC析出形貌由尺寸较小的块状转变为尺寸相对较大的十字放射状;TiC强化相的引入有效地提高了熔覆层的显微硬度和耐磨性,且降低了熔覆层粘着磨损的倾向,并增强了其抗磨粒磨损的能力;相比于单一2205不锈钢熔覆层,TiC强化不锈钢熔覆层在3.5%NaCl水溶液中的钝化能力下降,但同步补充Cr元素能够有效改善其耐腐蚀性能。

TiC reinforced stainless steel laser coatings were prepared on the surface of 16 Mn steel with mechanically mixed 2205 stainless steel,ferrotitanium and Cr3C2 powders as raw materials,and microstructure,friction and wear and electrochemical corrosion behavior of the coatings were studied. The results show that the microstructure of the coatings is mainly composed of α-Fe,γ-Fe and TiC precipitates,Ti and C elements react fully,there is no Cr3C2 ceramic phase residue,and no any other phases are formed. With the increase of TiC ratio,the content of γ-Fe phase decreases,and the morphology of TiC precipitates changes from smaller blocks to relatively large crosslike. The introduction of TiC strengthening phase effectively improves the microhardness and wear resistance of the coatings,reduces the tendency of adhesive wear of the coatings,and enhances its ability to resist abrasive wear. Compared with the single 2205 stainless steel coating,the passivation ability of the TiC strengthened stainless steel coatings in 3. 5% NaCl solution is decreased,but the corrosion resistance of the coating layer can be effectively improved by synchronously adding Cr element.