Stress Measurement Using a Bilayer Metal-Ceramic Strip

Residual stresses that develop in metal/ceramic bonded systems due to thermal expansion mismatch have been calculated using finite element modelling and measured experimentally using a simple bilayer strip. Bending in the strip occurs during cooling due to the stress asymmetry. Residual stresses are calculated by measuring the deflection of the strip and the temperature at which the strip is flat. Various compositions of both copper and nickel pastes, with and without glass and other second phase additions were evaluated on glass-ceramic. The effects of further processes, e.g. thermal cycling, brazing and plating, are also reported in this work.