Thickness-dependent phase evolution and bonding strength of SiC ceramics joints with active Ti interlayer

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• 作者：Hui Yang^a ; ^b ; ¹ ; Xiaobing Zhou^b ; ^c ; ¹ ; Wen Shi^a ; Ji Wang^b ; Peng Li^b ; Fanyan Chen^b ; Qihuang Deng^b ; Jaehyung Lee^c ; Young-Hwan Han^c ; Feng Huang^b ; Liu He^b ; Shiyu Du^b ; Qing Huang^b ; ^{huangqing@nimte.ac.cn}
• 关键词：SiC ; Joining ; Diffusion ; MAX phase
• 刊名：Journal of the European Ceramic Society
• 出版年：2017
• 出版时间：April 2017
• 年：2017
• 卷：37
• 期：4
• 页码：1233-1241
• 全文大小：4322 K
• 卷排序：37

文摘

A robust solid state diffusion joining technique for SiC ceramics was designed with a thickness-controlled Ti interlayer formed by physical vapor deposition and joined by electric field-assisted sintering technology. The interface reaction and phase revolution process were investigated in terms of the equilibrium phase diagram and the concentration-dependent potential diagram of the Ti-Si-C ternary system. Interestingly, under the same joining conditions (fixed temperature and annealing duration), the thickness of the Ti interlayer determined the concentration and distribution of the Si and C reactants in the resulting joint layer, and the respective diffusion distance of Si and C into the Ti interlayer differentiated dramatically during the short joining process (only 5 min). In the case of a 100 nm Ti coating as an interlayer, the C concentration in the joint layer was saturated quickly, which benefited the formation of a TiC phase and subsequent Ti3SiC2 phase. The SiC ceramics were successfully joined at a low temperature of 1000 °C with a flexural strength of 168.2 MPa, which satisfies applications in corrosive environments. When the Ti thickness was increased to 1 μm, Si atoms diffused easily through the diluted Ti-C alloy (a dense TiC phase was not formed), and the Ti5Si3 brittle phase formed preferentially. These findings highlight the importance of the diffusion kinetics of the reactants on the final composition in the solid state reaction, particularly in the joining technique for covalent SiC ceramics.