Strength Evaluation of Ceramics-Metal Joints

Silicon nitride ceramics were diffusion-bonded to Nimonic 80A, a Ni-based metal, by use of Ni-plate insert between them. By applying FEM techniques a variety of stresses developed in this ceramics-metal combination was estimated. The strength of joints under residual stress conditions was then calculated to evaluate the effect of insert introduced for stress release. The results satisfactorily agreed with the measured tensile strength for various thicknesses of Ni insert: the Ni thickness has an optimum value to yield a maximum tensile strength.