三氧化钨陶瓷的压敏特性和机理

采用传统电子陶瓷烧结工艺,制备了无掺杂物的三氧化钨(WO3)陶瓷。分析了陶瓷样品经淬火和不同气氛下处理后的微结构和压敏电学特性。研究表明:陶瓷冷却过程中在氧吸附的作用下,WO3陶瓷晶粒表面呈现氧元素富集。分析认为,晶粒表面吸附的氧与晶粒内的电子作用,在晶粒表面形成界面态,并进一步在晶界形成Schottky势垒,这可能是WO3陶瓷压敏行为的起源。根据实验结果,提出了一种修正的晶界Schottky势垒模型,解释了WO3陶瓷的压敏行为。

VARISTOR BEHAVIOR AND MECHANISM OF TUNGSTEN TRIOXIDE CERAMICS

Pure tungsten trioxide （WO3） ceramic was prepared by conventional electroceramic sintering technique. The microstructure and varistor property of samples that were quenched and annealed in different treatment atmospheres were investigated. The results show that there is enrichment of oxygen on the grain surface of WO3 ceramics caused by the adsorption of oxygen in the cooling process,it is proposed that these adsorbed oxygen interacts with electrons from WO3 grains form the interface states in the grain surface,and then Schottky potential barriers can form at the grain boundaries,which could be the root cause of varistor behavior of WO3 ceramic. Based on the experimental results,a modified Schottky potential barrier model is proposed to explain varistor behavior of pure WO3 ceramic.