مشخصات پژوهش

صفحه نخست /Ultra-high voltage SnO2 based ...
عنوان Ultra-high voltage SnO2 based varistors prepared at low temperature by two-step sintering
نوع پژوهش مقاله چاپ‌شده در مجلات علمی
کلیدواژه‌ها VaristorSnO2Two-step sinteringLow temperature sinteringUltra-high voltage
چکیده In this research, full density, single phase microstructure (in the XRD and SEM detection limits), and fine-grained SnO2 varistors with an average grain size of 0.65 μm was acquired at low temperature by the two-step sintering technique. The sintering temperature was successfully decreased from 1300 °C in the normal sintering to 1150 °C and 1100 °C of respectively the first and the second stage in the two-step sintering. The mechanism of grain growth suppression of the two-step sintered samples was discussed and it was suggested that in addition to triple point junction, solute drag and/or nano-secondary phases contribute to cease the grain growth. These SnO2 varistors exhibited ultra-high breakdown electric field of 26 kV/cm with a nonlinear coefficient of about 120 in the 1–10 mA/cm2 standard. The exact evaluation showed that this high value of the nonlinear coefficient is artificial and was the result of joule-self heating phenomenon. The true value of the nonlinear coefficient (28) is measured within the 0.1–1 mA/cm2 standard. Due to the joule self-heating phenomenon, the thermal runaway was observed for ultra-high voltage SnO2 varistors in DC-accelerated aging test conditions (0.85 E1mA/cm2 and room temperature). By changing DC-accelerated aging electric field to 0.85 E0.1 mA/cm2, TSS3-20h presented excellent stability after 10 h from room temperature to 75 ᵒC.
پژوهشگران مهدی عبداللهی (نفر ششم به بعد)، ایمان صفایی (نفر پنجم)، پژمان محمودی (نفر چهارم)، سیامک علیپور (نفر سوم)، مهدی دلشاد (نفر دوم)، محمد مالکی شهرکی (نفر اول)