Phase equilibria in the RuO_2-Bi_2O_3-NiO and RuO_2-AI_2O_3-MiO systems

摘要

After firing, thick film resistors consist of a conduc-tive phase in a glass matrix. The conductive phase is either RuO2 or ruthenates, usually Bi2Ru2O7 [1,2]. Specific conductivities of RuO2 and Bi2Ru2O7 are 40 X 1CT6 ohm cm and 150 x 10"6 ohm cm, respec-tively [3,4]. However, resistors prepared from a mixture of ruthenium oxide or ruthenates and a glass phase have relatively high positive temperature resistivity coefficients (TRC). To decrease the TCR, small amounts of so-called TCR modifiers, i.e. semiconducting oxides with negative TCR, are added. Among many others, NiO is reported to be sometimes used as a TCR modifier [5].