The effects of oxygen partial pressure (pO2) in the calcination process of perovskite (Na0.5K0.5)NbO3 (NKN) are investigated in terms of morphology and defect structure. Ceramic powders calcined in low-pO2 atmospheres exhibit cubic-shaped particles with smaller mean diameter. The tail of the absorption edge in UV-visible diffuse reflectance spectra becomes smaller at low-pO2 atmospheres in the calcination process, implying the suppression of alkali vacancies. The smaller powder size and lower concentration of alkali vacancies in low-pO 2-calcined powder improves the sinterability, thereby leading to higher resistivity. Therefore, the low-pO2 calcination is an essential process for NKN-based piezoelectrics.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)