JIANG Yongchang1, SHI Wen2, ZHANG Qian3, CHENG Qianke4, YAO Zheng5
(Nano-Science and Technology Research Center, Shanghai University, Shanghai 200444, China)
Abstract: Additives powder was calcined under different temperature schedules and then ZnO varistor ceramics were prepared. The effects of additives calcination on the ceramics were studied by TG-DTA, SEM and XRD, and the electrical properties of the prepared varistor ceramics were measured. The results show that a homogeneous composite oxide is generated and it is helpful to the structural uniformity of the ceramics. The ZnO varistor ceramic with additives calcined at 850 ℃ for 90 min exhibits excellent electrical properties. Its potential gradient is 243 V/mm, its voltage ratio reaches 1.68, its aging coefficient is 0.85 and the passing rate of 300 A 2 ms rectangular current test is 100%.
Key words: ZnO varistor ceramic; calcination; electrical properties; voltage ratio