Fabrication of (Ba,Pb)TiO3-based tapes with positive temperature coefficients of resistivity by the oxidation of malleable, metal-bearing precursors (the volume identical metal oxidation process)

Abstract

The feasibility of producing (Ba,Pb)TiO3-based thermistor tapes by the oxidation of malleable, metal-bearing precursors has been demonstrated. Intimate Ba–Pb–Ti–TiO2-bearing powder mixtures, produced by high-energy vibratory milling, were packed within a fugitive metal can and then compacted and formed into tapes of uniform thickness by cold drawing and rolling. The tape-shaped precursors were oxidized and converted into (Ba,Pb)TiO3-based tapes with a series of heat treatments at ≤1120 °C. With proper control of thermal treatments and chemical additions (Sb2O3 + MnO2 dopants), positive-temperature-coefficient-of-resistivity thermistors were produced that exhibited significant increases in resistivity commencing at temperatures ≥350 °C.