Kinetics of the Growth of Reaction Layer at the Bonding Interface of Si₃N₄ to Metal Joints

Study on Bonding of Heat-Resisting Fine Creamics (Report 8)

Abstract

Kinetics of the reaction layer growth in Si₃N₄-W brazed joints was investigated using Cu-5%Cr, Cu-I%Nb, Cu-3%V, Cu-5%Ti and Cu-10%Zr liquid insert metals. It was elucidated that the reaction layer growth could be expressed by Johnson-Mehl type equation with time exponent 'n' of 1/2. EPMA analysis of elements in the reaction layer revealed that Cr, Nb, V, Ti and Zr contents slightly decreased toward Si₃N₄, and that N content was almost constant. From the consideration of activation energy for reaction layer growth, it may be deduced that the reaction layer growth was controlled by diffusion of Cr, Nb, V, Ti and Zr in the reaction layer from the melted insert metal to Si₃N₄.