Relation of the Particle Size of RuO2in Cermet Resistor Inks to the Electrical Properties of Fired Resistors

It has been reported that the electrical properties of RuO2-.based thick-film resistors are dependent on the particle size of the Ru02in the inks used to make the resistors. In order to explain this dependence, a mathematical analysis was made to see if the "mixing rule" equations used to blend end-member cermet resistor inks to give inks with intermediate resistance values could be applied. This analysis led to the conclusion that these mixing rules cannot be used to explain file changes in resistence and the temperature coefficient of resistance (TCR) that occur as the particle size of the RuO2in the inks is varied. It was found, however, that alterations in the elemental resistor structure associated with the variations in the particle size of the oxide could be used to explain the changes observed.