Effect of additives on the electrical properties of a (Ba0.92Sr0.08)TiO3-based positive temperature coefficient resistor

In the present work, the effects of the additives (BN, Y2O3+Nb2O5, Sb2O3+Nb2O5, and Cr) on the electrical properties of (Ba0.92Sr0.08)TiO3-based positive temperature coefficient resistor (PTCR) were investigated. It was noted that the addition of BN lowered the sintering temperature of the material system studied. A proper amount of BN could enhance the PTC effect, but the room-temperature resistivity would increase with increasing the content of BN. The addition of double donor Sb2O3+Nb2O5 could lead to a lower room-temperature resistivity than that of Y2O3+Nb2O5. Metal Cr was also added to further reduce the resistivity. The low room-temperature resistivity and PTC behavior was achieved by controlling both the metallic Cr content and the process of reducing sintering and oxidation treatment.