Glass composition for the thick-film resistors

The considerable part of thick-film inks (TFI) for the production of hybrid circuits using screen-printing technology is glass. Phosphate glasses for production of thick-film resistors (TFR), which can substitute now currently used lead borosilicate glasses, have been investigated. The TFI were produced from glass and RuO2 by the addition of the screening agent and vehicle and deposited on an alumina substrate Rubalit (R) 708. Phosphate glasses have suitable thermal and chemical properties for the formation of high-quality coating on alumina with a high electrical resistivity, sufficient chemical durability and viscosity-temperature relationship suitable for TFI A complete saturation of RuO2-film with the glass phase without chemical interaction between glass-RuO2 and glass-alumina substrate was found at sintering temperature 850(0)C. The film near the substrate has a low content of Ru and a high content of Al owing to diffusion of Al from the substrate. Owing to suitable properties the investigated phosphate glasses are convenient to be applied in the production of RuO2 based TFR by printing on alumina.