Authors: Satoru Ishihara Kenichi Kakimoto Isao Kagomiya
Publish Date: 2011/02/04
Volume: 46, Issue: 11, Pages: 3822-3827
Abstract
Leadfree Na05K05NbO3 NKN piezoelectric ceramics were sintered with a new process “twostep mixing process” in which a part of alkali source powders was initially preserved and mixed with the rest matrix powders after the calcinations step As a result the sintering of NKN ceramics was improved and the sample sintered at 1082 °C with the initial preservation ratio R A of 5 demonstrated the highest density of ρ = 438 g/cm3 971 of the theoretical density compared with ρ = 436 g/cm3 967 of the theoretical density for the nonpreservation specimen R A = 0 The former sample showed the best piezoelectric constant of d 33 = 125 pC/N and electromechanical coupling coefficient of k p = 042 while the latter sample had d 33 = 116 pC/N and k p = 037 These results indicated that the twostep mixing process was effective for the sintering of leadfree NKN ceramics despite no sintering additive and cold isostatic pressing were used
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