Yellow Tungsten Oxide Ceramic
Yellow tungsten oxide is new n type semiconductor ceramic material, widely applied in fuel cell and reversible electrochromic device, catalyst, gas sensor. In recent years, it is found that YTO based functional ceramic has nonlinear voltage-current characteristics, it is a potential varistor material. Compared to other varistor material, yellow tungsten oxide ceramic has lower nonlinear voltage – current characteristic. The volt – ampere characteristic curve reproducibility is not well, also has serious phenomenon of electrical relaxation. However, by adjusting producing process, microstructure and phase structure of yellow tungsten oxide ceramic will change, it will have change in electric property, so as to have linear voltammetric behavior.
Study on yellow tungsten oxide ceramic mainly use micro WO3 as raw material, with common electric ceramic producing method, change doping element and its ratio to produce micron WO3 ceramic and observe its electrical behavior.
Apart from that, with development of technology, requirement for tungsten product property is higher, nano yellow tungsten oxide is produced. Study shows that microwave calcination will turn YTO ceramic into rod shape W18O49. It has good reproducibility of current volt-ampere characteristics, and tempering, the sample will become spherical grains and has nonlinear I-V characteristics.