Electrical properties of laser-synthesized aluminum oxide-tungsten oxide ceramics

Electronic ceramics of the Al₂O₃-WO₃ system were synthesized by using a high-powered CO₂ laser. It was shown that these ceramics can be used as linear thermistor materials. The linear temperature range of the Al₂O₃-WO₃ system was ∼200°C, the nonlinear deviation e was <2%, the thermistor constant B was <10³, and the temperature coefficient was between -0.2%/°C and -0.8%/°C. These parameters could be adjusted by changing the composition of the samples and the laser-synthesis parameters. The present study showed that the materials should be encapsulated if they are to be used in an oxidizing atmosphere. The current-voltage curves of the present materials were symmetrical around the coordinate origin, which also is a necessary condition for judging whether or not a thermistor is linear.