Critical relationships between particle size, composition, and microstructure in thick-film resistors

It is shown that the microstructure of RuO/sub 2/-based thick-film resistors depends on the volume fraction of RuO/sub 2/, particle size of RuO/sub 2/, and particle size of glass, but that these are not independent variables. Rather, they are related through a coverage factor which describes the extent of coverage of glass particles in the unfired resistors. Two critical values of the coverage factor are identified, separating regions of constant microstructure, changing microstructure, and unstable microstructure.<>