Pure K0.5Na0.5NbO3 lead-free piezoelectric ceramics without any dopants/additives were sintered at various temperatures (950–1125 °C) in low pO2 atmosphere (pO2 ~ 10−6 atm). All ceramics exhibit high relative densities (> 94%) and low weight loss… Click to show full abstract
Pure K0.5Na0.5NbO3 lead-free piezoelectric ceramics without any dopants/additives were sintered at various temperatures (950–1125 °C) in low pO2 atmosphere (pO2 ~ 10−6 atm). All ceramics exhibit high relative densities (> 94%) and low weight loss (< 0.6%). Compared to the ceramics sintered in air, the ceramics sintered in low pO2 exhibit improved electrical properties. The piezoelectric constant d33 and converse piezoelectric constant d33* are 112 pC/N and 119 pm/V, respectively. The ceramics show typical ferroelectric behavior with the remnant polarization of 21.6 µC/cm2 and coercive field of 15.5 kV/cm under measurement electric field of 70 kV/cm. The good electrical properties of the present samples are related to the suppression of volatility of the alkali cations during the sintering process in low pO2 atmosphere.
               
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