RI 7458 Yttria And Dysprosia As High-Temperature Thermistor Materials

Sintered yttria and sintered dysprosia can be used to make single-component thermistors having typical thermistor geometries and operable in the temperature range 500° to 1,200° C. However, at these temperatures, instability of platinum electrodes can contribute a slight aging effect if the thermistor is kept near 1,200° C for long periods. Typical characteristics at 500° C for an yttria disk thermistor 12 mm in diameter and 2 mm thick are a resistance of 12.4 megohms and a temperature coefficient of resistance of -3.8 percent per degree C. Typical characteristics at 500° C for a dysprosia thermistor of the same dimensions are a resistance of 1.84 kohms and a temperature coefficient of resistance of -1.6 percent per degree C.