Glass/Substrate Interaction in Model RuO5‐Glass Double‐Layer Thick Films

Chemical interaction between RuO 2 ‐glass thick‐film resistors and substrates was studied by observing microstructural changes in model double‐layer thick films, which were composed of a top glass layer and an RuO 2 layer. The concentration profiles of Al, Pb, and Ru in the film were analyzed. A new glass layer formed on the alumina substrate during firing, the formation of which resulted from dissolution of A1 2 O 3 into glass. A mechanism of microstructural changes has been proposed based on the results of EPMA.