Characterization of SiC Ceramic Joints Brazed Using Au⁻Ni⁻Pd⁻Ti High-Temperature Filler Alloy

Huamin He; Chuanyang Lu; Yanming He; Wenjian Zheng; Jianguo Yang; Limei Wang; Yuan Sun; Zengliang Gao

doi:10.3390/ma12060931

Characterization of SiC Ceramic Joints Brazed Using Au⁻Ni⁻Pd⁻Ti High-Temperature Filler Alloy

Materials (Basel). 2019 Mar 20;12(6):931. doi: 10.3390/ma12060931.

Authors

Huamin He¹, Chuanyang Lu², Yanming He³, Wenjian Zheng⁴, Jianguo Yang⁵, Limei Wang⁶, Yuan Sun⁷, Zengliang Gao⁸

Affiliations

¹ Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014, China. 2111602136@zjut.edu.cn.
² Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014, China. lvcykk@163.com.
³ Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014, China. heyanming@zjut.edu.cn.
⁴ Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014, China. zwj0322@zjut.edu.cn.
⁵ Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014, China. yangjg@zjut.edu.cn.
⁶ Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014, China. lmwang@zjut.edu.cn.
⁷ Department of Superalloy, Institute of Metal Research, Chinese Academy of Science, Shenyang 110016, China. yuansun@imr.ac.cn.
⁸ Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014, China. zlgao@zjut.edu.cn.

Abstract

In this work, (Au₇₉Ni₁₇Pd₄)₉₆Ti₄ (wt.%) filler alloy was designed and employed to join SiC ceramics. The effects of brazing temperature and soaking time on the microstructure and fracture morphology of joints were investigated. The results show that the joint obtained can be described as SiC/reaction layer/braze/reaction layer/SiC. The reaction layer was composed of TiC and Au (Si, Ti). The wettability of the filler alloy toward the SiC ceramics was analyzed. The braze zone was mainly constituted by Pd₂Si, Ni₂Si, and Au (Ni, Si). A large number of nano-sized TiC particles were distributed within the Au (Ni, Si) layer. The formation mechanism of the braze containing different phases was discussed. The brazing temperature and soaking time had a significant effect on the reaction layer at the SiC/braze interface and TiC particles within the Au (Ni, Si) layer, while they showed a negligible effect on the Pd₂Si and Ni₂Si within the braze. The inherent reason was also clarified in detail. The joint fractography indicated that a good bonding was achieved between the filler alloy and SiC, while joint fracture was primarily induced by the thermal stresses residing after the brazing cycle.

Keywords: SiC ceramic; high-temperature brazing; microstructure; residual stress.

Abstract

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