Basic adhesion mechanisms in thick and thin films

In this quarter, continued experiments were conducted to separate and quantify the chemical from the micromechanical contributions to the adhesion strength. It was shown that silver has a higher chemical adhesion than gold to a glass of composition similar to that of frits used in commercial thick-film conductors. Isothermal sintering studies of gold, silver, and copper powders in the presence and absence of the liquid glass phase showed that densification rates and microstructure differed markedly in each metal powder. Large densification rate differences were also noted in gold powders with different morphologies and particle size distributions. During this quarter, the possibility was considered that reactively and mixed-bonded inks have a common or similar adhesion mechanism. The results of several recent experiments, which are presented, lead to the consideration of such a mechanism.