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Formation of interfacial microstructure in brazing of Si{sub 3}N{sub 4} with Ti-activated Ag-Cu filler alloys

Journal Article · · Scripta Metallurgica et Materialia
;  [1]
  1. Helsinki Univ. of Technology, Espoo (Finland). Dept. of Materials Science and Engineering

Advanced ceramics like silicon nitride are increasingly used as structural components in demanding applications such as turbine engines and heat exchangers. Owing to the difficulties in fabrication of complicated geometries from brittle ceramics, like Si{sub 3}N{sub 4}, adequate joining techniques have to be provided. Brazing with active filler metals, most of which are based on the Ag-Cu-Ti system, is increasingly used for joining of Si{sub 3}N{sub 4} to other ceramics and metals. The present work concentrates on the formation of the interfacial microstructures in the brazing of silicon nitride with AgCuTi alloys using both thermodynamic analysis and brazing experiments. This article is part of a larger program, in which the role of titanium in active brazing of ceramics has been studied. The interfacial reactions were investigated by brazing Si{sub 3}N{sub 4} with two commercial filler alloys and with different binary AgCu filler alloys produced in the laboratory. Phases formed during joining were characterized with the SEM/EPMA and SIMS techniques. The thermodynamic information is obtained from the descriptions of the ternary Ti-Si-N and Ti-Cu-Ag systems assessed in previous studies and from the literature concerning the Ag-Si and Cu-Si systems.

OSTI ID:
55430
Journal Information:
Scripta Metallurgica et Materialia, Journal Name: Scripta Metallurgica et Materialia Journal Issue: 8 Vol. 32; ISSN 0956-716X; ISSN SCRMEX
Country of Publication:
United States
Language:
English