Residual stress generation during constrained sintering of layered ceramic thin-film structures

摘要

This work investigates the sintering kinetics and residual stresses which develop in thin layered ceramic structures when sintered on a rigid substrate. A continuum constitutive framework to model the evolution of the microstructure and stresses in the sintering layers under non-isothermal conditions is presented. The sintering model is used to investigate the constrained sintering behaviour of layered ceramic structures used in solid oxide fuel cells (SOFC). Samples of a 50 mu m thick SOFC film were screen-printed on a fully dense yttria-stabilised zirconia substrate and then sintered at temperatures ranging from 1100 deg C to 1300 deg C. Measured values of relative density and average grain size are compared with model predictions. A correlation between residual stresses extracted from curvature measurements and analytical predictions revealed these stresses to have been mostly relieved during the subsequent cooling by microcrack formation.