Jeong, Dae-Yong Lee, Seong-Hwa Song, Hyun-Cheol Choi, Kyeong-Ho Cho, Jin-Ho 2024-01-20T17:32:47Z 2024-01-20T17:32:47Z 2021-09-02 2011-03 0374-4884 https://pubs.kist.re.kr/handle/201004/130612 Lead-free piezoelectric ceramics of (K0.5Na0.5)NbO3 (KNN) were produced by using hydrothermally synthesized KNbO3 (KN) and NaNbO3 (NN) powders in a microwave furnace to reduce the volatilization of the alkaline elements. The KNN ceramics were synthesized by using a hydrothermal KN and NN mixed powder, a 1 mol% CuO-added hydrothermal KN and NN mixed powder and KNN calcined at various temperatures. The hydrothermal KN and NN powder and the calcined KNN powder had a pure perovskite phase while KNN ceramics with 1 mol% CuO showed a pyrochlore second phase. The CuO-added KNN ceramics sintered at 1050 degrees C for a short sintering time of 5 min at a fast heating rate of 50 degrees C/min to prevent evaporation of K2O and Na2O showed the highest piezoelectric properties (d(33) = 89 pC/N and k(p) = 0.28). The X-ray diffraction and the scanning electron microscopy results indicate that fast heating and short sintering time can affect the phase formation sequence in KNN ceramics. English KOREAN PHYSICAL SOC PIEZOELECTRIC PROPERTIES MICROSTRUCTURE Hydrothermal Synthesis and Microwave Sintering of (K0.5Na0.5)NbO3 Ceramics Article 10.3938/jkps.58.663 1 JOURNAL OF THE KOREAN PHYSICAL SOCIETY, v.58, no.3, pp.663 - 667 JOURNAL OF THE KOREAN PHYSICAL SOCIETY 58 3 663 667 scie scopus kci 000288414600024 Physics, Multidisciplinary Physics Article; Proceedings Paper PIEZOELECTRIC PROPERTIES MICROSTRUCTURE Hydrothermal Piezoelectrics Microwave sintering Lead-free