Experimental determination of residual stress in silicon nitride diffusion bonds obtained by high-energy X-ray diffraction

High resolution X-ray scanning diffractometry has been used to study the residual strain in binary metal/ceramic (Ni/Si3N4) and ceramic/ceramic (Si3N4/Ni thin film/Si3N4) diffusion bonds. Bonds were fabricated by simultaneous high temperature heating and uniaxial pressing. The axial and radial strain profiles have been determined along selected lines perpendicular to the bonding interface inside the ceramic bodies. The X-ray experiments have been done at the energy of 60 keV, which assured a very small absorption, and therefore, strain fields have been measured in the ceramic bulk. Strains showed higher values near the interface that decreased with the distance.