Cold sintering ZnO based varistor ceramics with controlled grain growth to realize superior breakdown electric field

2021 ◽  
Vol 41 (1) ◽  
pp. 430-435
Author(s):  
Xuetong Zhao ◽  
Jie Liang ◽  
Jianjie Sun ◽  
Jing Guo ◽  
Sinan Dursun ◽  
...  
2014 ◽  
Vol 1070-1072 ◽  
pp. 625-629
Author(s):  
Xue Tong Zhao ◽  
Rui Jin Liao ◽  
Jian Ying Li

ZnO-based varistor ceramics with different recipes were prepared in this research. It was found that the grain growth was restrained with the addition of Ba2+. SEM results indicated that the grain size of ZnO varistor ceramics with Ba2+ was reduced to 4.7 μm. Correspondingly, the breakdown electric field of the ZnO varistor samples were extremely enhanced to 8730 V/cm. The results of ac conductance response showed that two relaxation peak 1 and 2 with activation energy at about 0.24 eV and 0.36 eV were observed in 100-250 K, which were not affected by additives. However, a new conductance relaxation peak 3 in 300-450 K for sample B and C can be found, whose activation energy were varied from 0.55 eV to 0.65 eV with the addition of Ba2+. It was put forward that the electrical properties of ZnO varistor ceramics may be associated with the conductance relaxation peak 3.


2003 ◽  
Vol 433-436 ◽  
pp. 435-438
Author(s):  
Rudi Ono ◽  
Makato Fujimaki ◽  
Hoon Joo Na ◽  
Satoshi Tanimoto ◽  
Takashi Shinohe ◽  
...  

2009 ◽  
Author(s):  
◽  
Peter A. Norgard

WITHDRAWN - [ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] In the not-so-distant future, a need is foreseen for a high-performance, compact switch that is capable of repetitively switching kilovolts to megavolts and several hundred joules, all while delivering a square pulse with a fast current rise time. Many industrial and military applications currently exist that could take advantage of these operating characteristics, and many more are surely to be developed in the coming years. The proposed approach to realizing the goal of producing a fast rise time, high voltage, high energy, repetitive switch technology is to employ a pressurized, flowing oil dielectric switching medium. Oil pressure and oil flow will be used to increase the rate of dielectric recovery following a high energy discharge, thus enabling a much higher operating repetition frequency; oil pressure will be utilized to control gaseous switching byproducts, and oil flow will be utilized to control solid and gaseous switching byproducts. The well-known increase in breakdown electric field strength with increasing oil pressure will be utilized to reduce the gap separation, thus reducing the inductance of the electrical arc and increasing the rise time of the current pulse produced during breakdown. An experiment was designed and undertaken to evaluate the complete statistical performance of the breakdown electric field of an emerging dielectric liquid, poly-[alpha]olefin, with respect to variations in oil pressure, oil flow rate, peak rate of rise of the voltage, and gap separation.


2018 ◽  
Vol 33 (6) ◽  
pp. 065013 ◽  
Author(s):  
S Mandal ◽  
M B Kanathila ◽  
C D Pynn ◽  
W Li ◽  
J Gao ◽  
...  

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