Microstructural Analysis on Bonding Interface in Si₃N₄ to Metal Joints Bonded using Cu-Base Insert Metals

Study on Bonding of Heat-Resisting Fine Ceramics (Report 6)

Abstract

Bonding of Si₃N₄ to W using Cu-5%Cr, Cu-1%Nb, Cu-3%V, Cu-5%Ti and Cu-10%Zr insert metals was conducted in a vacuum furnace. The reaction layer existed at the interface between Si₃N₄ and insert layers in Si₃N₄-W joints. Cr, Nb, V, Ti or Zr was concentrated in the region adjacent to Si₃N₄, and Cu was enriched in the center region of insert layer for all insert metals used. From the results of X-ray diffraction analysis, it was found that Cr₂N, CrN and CrSi₂, NbN and Nb₃Si, VN and V₆Si₅, TiN and Ti₅Si₃, ZrN and Zr₅Si₃ existed in thee reaction layer. The thermodynamics calculation suggested that these nitrides and silicides could be formed by the reaction between Si₃N₄ and Cr, Nb, V, Ti or Zr containing in the melted insert metal in the first stage of reaction layer formation.