Microstructure and electrical properties of xY2O3-(1-x)LaCrO3 thermosensitive ceramics prepared by spark plasma sintering

Abstract The high temperature, negative temperature coefficient (NTC), thermosensitive ceramics xY2O3-(1-x)LaCrO3 (x = 0.4, 0.5, 0.6, 0.7) were prepared via spark plasma sintering. The effects of components, sintering temperature, and sintering pressure on the electrical properties of the composite ceramics were studied. The composite NTC ceramics were composed of orthogonal perovskite structure LaCrO3 and Y2O3. The presence of Cr3+ and Cr4+ was confirmed using X-ray photoelectron spectroscopy, which may be responsible for the hopping conduction. The composite NTC ceramics sintered at 1500 °C had good electrical properties. The resistivities and the coefficient of temperature sensitivity (B) increased with the rise in Y2O3 content. The values of ρ250, ρ700, B400/700, and activation energy of xY2O3-(1-x)LaCrO3 composite NTC ceramics sintered at 1500 °C were 1.7 × 1010–5.51 × 1010 Ω cm, 4.32 × 104–6.16 × 106 Ω cm, 14,111–16,223 K, and 1.221–1.403 eV, respectively. The composite NTC ceramics prepared at different sintering pressures displayed identical electrical properties.