caa a22 4500 388018674 CHVBK 20180307124917.0 cr unu---uuuuu 161130e199806 xx s 000 0 eng 10.1557/JMR.1998.0217 doi S0884291400044538 pii (NATIONALLICENCE)cambridge-10.1557/JMR.1998.0217 Improvement on the degradation of microwave sintered ZnO varistors by postannealing [Elektronische Daten] The microwave sintering process not only densified the ZnO materials in a higher rate, but also resulted in significantly better varistor characteristics. Large nonlinear coefficient and low leakage current density were attained by cooling the samples under a rate of 80 °C/min after sintering, followed by 600 °C postannealing for 60 min under oxygen atmosphere. Inappropriate annealing deteriorated the varistor characteristics that can either be attributed to the insufficient reoxidation along grain boundaries when annealed in N2 (or air) or loss of Zn species in these regions when annealed at 750 °C (900 °C). By contrast, the degradation behavior of these materials can be improved by the annealing process regardless of the annealing atmosphere or temperature. Copyright © Materials Research Society 1998 Chen Chang-Shun Department of Mechanical Engineering, HWA-HSIA College of Technology and Commerce, Taipei 235, Taiwan, Republic of China Kuo Cheng-Tzu Institute of Materials Science and Engineering, National Chiao-Tung University, Hsinchu 30050, Taiwan, Republic of China Lin I-Nan Materials Science Center, National Tsing-Hua University, Hsinchu 30043, Taiwan, Republic of China Journal of Materials Research Cambridge University Press 13/6(1998-06), 1560-1567 0884-2914 13:6<1560 1998 13 JMR https://doi.org/10.1557/JMR.1998.0217 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1557/JMR.1998.0217 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Chen Chang-Shun Department of Mechanical Engineering, HWA-HSIA College of Technology and Commerce, Taipei 235, Taiwan, Republic of China NATIONALLICENCE 700 1- Kuo Cheng-Tzu Institute of Materials Science and Engineering, National Chiao-Tung University, Hsinchu 30050, Taiwan, Republic of China NATIONALLICENCE 700 1- Lin I-Nan Materials Science Center, National Tsing-Hua University, Hsinchu 30043, Taiwan, Republic of China NATIONALLICENCE 773 0- Journal of Materials Research Cambridge University Press 13/6(1998-06), 1560-1567 0884-2914 13:6<1560 1998 13 JMR CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge