Interaction between Alumina and Binary Glasses

Interaction between 96% alumina and three binary glasses used as frits in thick-film technology is studied. A possible interfacial reaction mechanism where a melt glass penetrates into the alumina through the grain boundaries dissolving SiO2, one of the grain boundary components, is suggested. The formulation expressing the glass penetration rate into the alumina based on Poiseuilles law, assuming the driving force for the glass penetration is the capillary force, is consistent with the experimental growth rate of the reaction layer in the alumina. The formulation also clearly explains the relationship of the degree of glass penetration to the viscosity and the surface tension of the melt glass. The extraordinary difference in K, designated as the coefficient of penetration, between the calculated result and the experimental result suggests that the process of dissolving SiO2 into a melt glass at the alumina grain boundaries retards the glass penetration.