Simultaneous measurement of coefficient of thermal expansion and biaxial modulus of enamel thick films deposited on glass substrates by curvature technique

Abstract The measurement of the thermoelastic properties of enamel thick films deposited onto soda‐lime silicate glass is challenging. The film properties can be modified by the interdiffusion between the glass substrate and the enamel and by the crystallization that occur during the sintering. The average biaxial modulus and coefficient of thermal expansion of several enamel thick films deposited onto 700 µm glass substrates have been simultaneously measured using the curvature method. The value of the coefficient of thermal expansion measured with a dilatometer on enamel bulk samples is significantly higher, associated with the absence of diffusion and a different enamel structure. The interdiffusion of elements between the enamel film and the glass substrate has been demonstrated with Time‐of‐Flight Secondary Ion Mass Spectrometry (TOF‐SIMS). The amount of porosity ratio presents in the enamel film, evaluated via Scanning electron microscopy(SEM), has a great influence on the biaxial modulus. The amount of compressive stress in the enamel, calculated from the film thermoelastic properties, is strongly correlated with the mechanical performance of enameled glasses, investigated by Ring On Ring methods. Therefore, a high Young's modulus for the enamel and a mismatch of the coefficient of thermal expansion between the enamel film and substrate, the film having the lowest value, has been found to increase significantly the mechanical performance of the stack.