Measurements and Finite-Element Simulations of Residual Stresses Developed in Si3N4/Ni Diffusion Bonds

High-resolution X-ray scanning diffractometry has been used to study the residual strain in Si₃N₄/Ni diffusion bonds. Bonds were made by directly joining Ni and Si₃N₄ samples of same geometry by applying high temperature and enough mechanical pressure. The axial and radial strain profiles have been determined by X-ray diffraction in the ceramic bodies along selected lines perpendicular to the bonding interface. A very small absorption was assured as the X-ray experiments have been performed at the energy of 60 keV, which allowed measurements of the strain and stress fields in the ceramic bulk. The finite-element method calculations carried out showed an excellent agreement with the experimental data.