Effect of Zr addition on the interfacial reaction of the SiC joint brazed by Inconel 625 powder filler. Issue 13 (October 2021)

• Record Type: Journal Article
• Authors: Shi, Haojiang; Peng, Huabei; Chai, Yidi; Li, Ning; Wen, Yuhua; Bai, Dong; Liu, Zihao; Yan, Jiazhen; Zhang, Ruiqian; Li, Ming; Chen, Kangwei; Luo, Mingliang; Sun, Qi; Li, Rui; Dong, Xin
• Is Part Of: Journal of the European Ceramic Society. Volume 41:Issue 13(2021)
• Page Start: 6238
• Page End: 6247
• Publication Date: 2021-10
• Subjects: Interfacial reaction -- Brazing -- SiC -- Graphite -- Mechanical property; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2021.06.047
• Languages: English
• ISSNs: 0955-2219

Abstract

Highlights: Inconel 625 filling powders with different amounts of pure Zr addition are used to braze SiC ceramic. Sound SiC joints are obtained at 1400 °C. Zr is beneficial in suppressing the formation of graphite, which is a mechanically detrimental product of the reaction between Ni and SiC. When Zr addition reaches 40 wt%, the interface shows no sign of graphite. Thermodynamic calculations prove that Zr's activity surpasses that of Ni as the Zr content increases. Zr replaces Ni as the dominating element that reacts with SiC. A dense and consecutive ZrC layer is thus formed along the interface. The room-temperature shear strength of the SiC joint with no graphite reaches 81.97 MPa, which is almost three times higher than that of the joint with graphite. Abstract: Ni-based alloys are believed to be the most suitable brazing fillers for SiC ceramic application in a nuclear environment. However, graphite, which severely deteriorates the mechanical property of the joint, is inevitable when Ni reacts with SiC. In this paper, Different amounts of Zr powders are mixed with Inconel 625 powders to braze SiC at 1400 °C. When Zr addition reaches 40 wt%, the brazed seam confirms the absence of graphite. This research proves that Zr can avoid the graphite's formation by suppressing Ni's activity. The room-temperature shear strength of the joint with graphite's absence is tested to be 81.97 MPa, which is almost three times higher than that of the joint with graphite. The interfacial reaction process and mechanism of the SiC joint are investigated and explained in this paper using thermodynamic calculations.