| 引用本文: | 谢玉莹,刘思思,刘金刚,杨正航,姜胜强,杨世平.激光熔覆NiCoCrTaAl-TiC复合涂层组织性能及摩擦学性能[J].中国表面工程,2024,37(5):253~262 |
| XIE Yuying,LIU Sisi,LIU Jingang,YANG Zhenghang,JIANG Shengqiang,YANG Shiping.Organizational and Tribological Properties of Laser-melted NiCoCrTaAl-TiC Composite Coatings[J].China Surface Engineering,2024,37(5):253~262 |
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| 摘要: |
| Ni 基合金因其在高温条件下具有优异的性能，在航空航天、船舶制造、冶金化工等领域受到广泛的关注。为了进一步提高合金在严苛环境下的服役年限，采用激光熔覆技术在 K418 镍基合金表面设计并制备了 NiCoCrTaAl-TiC 复合涂层，探究 Al 含量对复合涂层组织形貌及摩擦学性能的影响，并在雨水、海水和润滑油等严苛工作环境下对涂层性能做进一步分析。 研究结果表明：添加 Al 元素后，复合涂层出现 Al2O3、AlNi3、Al4CrNi15、Al4Ni15Ta 等金属间化合物相，涂层内部组织构成发生改变；随 Al 含量增加，熔池边界逐渐消失，涂层硬度、耐磨性能呈先减小后增加的趋势，并在 Al 含量为 15wt.%时达到最佳，其耐磨性较 NiCoCrTa-TiC 涂层约提高 25%；在雨水、海水介质中浸泡 2 h 后在边界润滑条件下的磨痕深度及磨损量与未经处理涂层的基本相同，表明 Al 元素的添加提高了复合涂层的耐腐蚀性能。 |
| 关键词: 激光熔覆 复合涂层 显微组织 腐蚀介质 摩擦学性能 |
| DOI：10.11933/j.issn.1007-9289.20220420001 |
| 分类号:TH117；TN305 |
| 基金项目:国家自然科学基金（52175191） |
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| Organizational and Tribological Properties of Laser-melted NiCoCrTaAl-TiC Composite Coatings |
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XIE Yuying，LIU Sisi，LIU Jingang，YANG Zhenghang，JIANG Shengqiang，YANG Shiping
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School of Mechanical Engineering, Xiangtan University, Xiangtan 411105 , China
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| Abstract: |
| Ni-based alloys exhibit low density, good plasticity, high strength, and excellent corrosion and wear resistance under high-temperature conditions. Therefore, they are often preferred in high-temperature and harsh environments. They are widely used in various military engines and civil equipment fields such as thermal power generation, petrochemicals, and metallurgical industries. However, they are more prone to fatigue and creep damage in high-temperature environments, which seriously affect the working efficiency, reliability, and durability of equipment utilizing Ni-based alloys. To improve the service life of Ni-based alloys in harsh environments, NiCoCrTaAl-TiC composite powders were prepared via vacuum-mixed ball milling, and metal/ceramic composite coatings were successfully deposited on the surface of K418 nickel-based alloys via laser cladding technology. The phase compositions and microstructures of the coatings were examined using an X-ray diffractometer and metallographic microscope. The effects of different Al contents (0, 5, 10, and 15% ) on the mechanical and tribological properties of the NiCoCrTaAl-TiC composite coatings were examined using a micro-Vickers hardness tester, scanning electron microscope, high-speed reciprocating friction and wear tester, and ultra-depth-of-field microscope. Actual operating environments, such as rainwater environment (pH6.2), seawater immersion (pH8), and lubricating oil were simulated for the coating with the best wear resistance, and the corrosion and wear resistances of the coating in different environments were further examined. The results show that the composite coating is mainly composed of TiC, Cr2Ni3, Al2O3, and AlNi3 phases, and intermetallic compounds such as Al4CrNi15 and Al4Ni15Ta. The internal structure of the coating is dense and composed of dendrites in the middle and equiaxed grains at the top. As the Al content increases, the average hardness of the coating initially decreases and then increases. The strengthening mechanism of the hardness corresponds mainly to the joint strengthening of TiC, Al2O3, and AlNi3 phases. Under dry friction conditions, with increasing Al content, the wear loss of the coating initially increases and then decreases. Furthermore, the main wear form changes from adhesive to abrasive wear. In summary, when the Al content is 15wt.%, the composite coating exhibits the best microhardness, microstructure, and tribological properties, and its wear resistance is approximately 25% higher than that of the coating with 0wt.% Al content. Subsequently, the 15wt.% Al composite coating was immersed in rainwater and seawater for 2 h, and its friction coefficient was: lubricating oil ＜ rainwater ＜ seawater. The depth of the wear scar and amount of wear were essentially the same as those of the coating without corrosion treatment, indicating that the addition of Al can improve the corrosion resistance of the composite coating. |
| Key words: laser cladding composite coating microstructure corrosive media tribological properties |
