等离子熔覆Fe基/Co-WC涂层的组织演变及性能

采用等离子熔覆技术,在Q235钢基体上熔覆添加Co-WC的Fe基粉末,制备了连续性好,无明显气孔和裂纹的Fe基/Co-WC耐磨熔覆涂层。研究了不同Co-WC含量下熔覆层的组织演变,表征了熔覆层的显微硬度分布。结果表明,随Co-WC含量增加,熔覆层组织由柱状晶逐渐向树枝晶转变,熔覆层中开始出现Fe3W3C、Fe6W6C、Co3W3C等新相。当Co-WC含量大于35%时,在熔覆层中开始出现形貌规则的鱼骨纹组织Co3W3C,该相的显微硬度HV达10.97GPa。当Co-WC含量达到50%以上时,树枝晶消失,出现大范围的规则排列、分布均匀的鱼骨纹组织。同时,随Co3W3C体积分数的增加,熔覆层显微硬度也随之增加,当Co-WC含量大于50%时,熔覆层显微硬度HV可达9.00~9.50 GPa。

Microstructures Evolution and Properties of Fe-based/Co-WC Cladding Coating by Plasma Cladding

Fe-based/Co-WC wear-resistant cladding layer was prepared on the Q235 steel substrate with Fe-based/Co-WC powder by a plasma cladding technique. Microstructure of the cladding layer with different contents of Co-WC was observed and its microhardness distribution was also revealed. The results show that the prepared cladding layer is of nice continuity without distinct pores or cracks. With the increase of Co-WC content, microstructure of the cladding layer changes from cellular structure to dendrite and some new phases such as Fe3W3C, Fe6W6C and Co3W3C appear. When the content of Co-WC is above 35%, herringbone Co3W3C, whose microhardness HV is 10.97 GPa, occurs in the cladding layer. Furthermore, proliferation arranges regularly, uniformly-distributed?herringbone structure forms and dendrites vanish when the content of Co-WC is up to 50%. Besides, microhardness of the cladding layer increases with more Co3Wc3. Microhardness HV of the cladding layer ranges from 9.00 to 9.50 GPa once the content of Co-WC exceeds 50%.