X-Ray and Microscopic Investigations of Resistors Containing CdO and RuO2

X-ray diffraction analysis was used to determine the crystalline phases of cadmium and ruthenium present after processing thick film resistors formulated from CdO, RuO2, and cadmium-lead-barium borate glass. On firing a phase with diffraction pattern characteristic of the pyrochlore-structure type is formed through reaction of RuO2and the modifying ions present in the glass. The observed cubic lattice parameter a0 corresponds closely to that reported for Pb2Ru206. The observed decrease in RuO2 correlated well with variations in resistance associated with changes in the firing temperature. It was observed that increased CdO content resulted in deterioration of the stability of the thick film resistors formed. Scanning electron microscopy showed that resistors high in CdO showed a higher concentration of voids than those formed from composites containing 70-80 percent glass.