| 摘要: |
| 采用TIG热源在钛合金表面堆焊Ti-SiC和Ti-SiC-C两种体系的粉末,形成表面陶瓷涂层.利用SEM和XRD等分析手段对两种配方陶瓷涂层的微观组织和物相进行了分析,用热力学方法计算了两种系统中各种可能发生的化学反应的Gibbs自由能变化.结果表明,Ti-SiC系统熔敷层的微观组织主要由树枝状的TiC、针棒状和菊花状的Ti5Si3相组成,其反应机理为:8Ti+3SiC→3TiC+Ti5Si3.Ti-SiC-C系统熔敷层的微观组织除了树枝状的TiC相之外,还有TiSi2和Ti3SiC2,其反应机理为:6Ti+3SiC+C→Ti3SiC2+TiSi2+2TiC.通过对两种系统的微观组织及化学反应分析可得出,在Ti-SiC系统中适当的添加石墨,可生成具有自润滑性能的Ti3SiC2相,避免Ti5Si3脆性相的生成. |
| 关键词: 钨极氩弧焊熔敷 陶瓷涂层 反应机理 热力学分析 |
| DOI： |
| 分类号: |
| 基金项目:湖北省教育厅资助项目(010403) |
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| Chemical reaction of ceramic coatings of Ti-Si-C system on Ti-5Al-2.5Sn substrate prepared by tungsten inert-gas arc cladding |
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YAN Wenqing1,2, GUI Chibin2, DAI Le3
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1.Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, China;2.School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510641, China;3.Military Representative Office of Navy, Henan Diesel Engine Group Limited Company 407 Factory, Luoyang 471039, China
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| Abstract: |
| The surface ceramic coatings were prepared on Ti-5Al-2.5Sn substrate by tungsten inert-gas arc depositon process. The microstructures and phases were analyzed using the method of SEM and XRD for the cladding coatings of Ti-SiC and Ti-SiC-C systems. Moreover, the changes of Gibbs energy for possible reactions in systems were calculated using thermodynamic analysis. The results shows that the main microstructure are composed with dendritic TiC and needle-shaped or chrysanthemum Ti5Si3 in the cladding coating of Ti-SiC system, the reaction mechanism is 8Ti+3SiC→3TiC+Ti5Si3. However, in Ti-SiC-C system, there are TiSi2 and Ti3SiC2 hybrid microstructure observed besides TiC. 6Ti+3SiC+C→Ti3SiC2+TiSi2+2TiC is the main reaction mechanism. In addition, the addition of graphite in Ti-SiC system favors to the generation of self-lubricating Ti3SiC2 phases, while the brittle Ti5Si3 phases are avoided. |
| Key words: tungsten inert-gas arc cladding ceramic coating reaction mechanism thermodynamic analysis |
