摘要
采用 5 k W CO2 连续激光在低碳钢表面激光熔覆了钴基合金涂层 (Co6 0 )及添加 2 5 % Cr3C2 (质量分数 )的钴基合金复合涂层 (Cr3C2 / Co) ,对比研究了 Cr3C2 对熔覆涂层的组织、显微硬度及耐腐蚀磨损性能的影响。结果表明 ,在本试验条件下可得到熔覆质量良好的 Co6 0及 Cr3C2 / Co涂层。 Co6 0涂层组织主要由大量初生枝晶γ固溶体及其间的共晶组织γ与 (Cr,Fe) 7C3组成。 Cr3C2 / Co涂层组织主要由未熔 Cr3C2 ,大量杆状和块状的富 Cr碳化物及其间的非常细小的枝晶及其共晶体组成 ,主要组成相为γ- Co,Cr7C3,Cr2 3C6 和未熔 Cr3C2 颗粒。添加的 Cr3C2 改变了Co6 0涂层的凝固特征 ,使 Co6 0涂层的亚共晶结晶方式转变为 Cr3C2 / Co涂层的过共晶结晶方式。未熔 Cr3C2 粒子起到了非自发形核作用 ,在其周围形成了许多富 Cr碳化物 ,并细化了涂层枝晶组织。 Cr3C2 / Co涂层的显微硬度以及在不同腐蚀介质中的耐磨性比 Co6 0涂层都有明显提高。
Laser cladding Co-based alloy coating (Co60) and Co-based alloy composite coating with 25(mass)% Cr_3C_2 particles (Cr_3C_2/Co) on low carbon steel substrate were obtained by 5-kW CO_2 continuous wave laser. Effects of Cr_3C_2 particles on microstructure, micro hardness and corrosion-wear resistance of Co-based alloy coating were discussed. The results showed that the good laser cladding coatings were obtained in the test conditions. The Co60 coating is consisted of many γ-Co dendritic solid solution and eutectic structure (γ-Co and (Cr,Fe)_7C_3) between the dendrites. The Cr_3C_2/Co coating is consisted of undissolved Cr_3C_2 particles, many different shape rich-chromium carbides (M_7C_3,M_ 23C_6) and very finer dendrite and eutectic structure between the carbides. Addition of Cr_3C_2 particles alters the solidification characteristic of the laser cladding coating Co60, transforming the hypo-eutectic crystal mode of Co60 to hyper-eutectic crystal mode of Cr_3C_2/Co. Cr_3C_2 particles play a role of non-spontaneity nucleation, and many rich-chromium carbides are formed around Cr_3C_2 particles, fining the dendrite structure. Micro-hardness and corrosion-wear resistance in different corrosion media of the Cr_3C_2/Co coatings are obviously higher than those of Co60 coatings.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2004年第9期1143-1148,共6页
Chinese Journal of Lasers
基金
安徽省科技厅重点科研项目 (0 4 0 2 2 0 0 4 )
安徽省教育厅自然科学研究项目 (2 0 0 3kj0 5 8)资助课题。
