| Synthesis and characterization of MnO2 added ( Na0.475K0.475Li0.05) (Nb0.9Ta0.05Sb0.05)O3 lead‑free piezoelectric ceramics |
Jae Min Cha, Jeong Woo Lee, Byeonghoon Bae, Yong Jeong Jeong, Chang‑Bun Yoon
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| Department of Advanced Materials Engineering, Korea Polytechnic University, Siheung‑si, Gyeonggi‑do 15073, Korea |
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Received: February 17, 2020; Revised: February 17, 2020 Accepted: March 17, 2020. Published online: April 30, 2020. |
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| ABSTRACT |
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Lead-free NKLNTS ceramics with promising piezoelectric properties were fabricated using the solid phase method, which is a general ceramic manufacturing method. MnO2 was added to NKLNTS ceramics as a sintering aid to improve piezoelectric and dielectric properties. The added MnO2 content was adjusted to 0, 0.1, 0.3, 0.5, and 0.7 wt%, the powder was calcined at 900 °C for 2 h, and then the sintering temperature was changed from 1000 to 1100 °C to study the optimum temperature and composition that yields excellent piezoelectric properties and sinterability. Archimedes method and scanning electron microscope (SEM) were used to evaluate the sinterability, X-ray diffraction analysis (XRD) was performed to confirm the crystallinity of the sintered body, and piezoelectric and dielectric properties were evaluated using a d33-meter and an impedance analyzer. When 0.1 wt% of MnO2 was added, it was confirmed that density was the highest at the sintering temperature of 1050 °C and had excellent piezoelectric and dielectric properties. When 0.3 wt% or more of MnO2 was added, piezoelectric and dielectric properties were decreased due to the decreased density. When NKLNTS-0.1wt% MnO2 was sintered at a sintering temperature of 1050 ℃ for 2 h, it had a density of about 97%. Furthermore, lead-free piezoelectric ceramics with excellent piezoelectric and dielectric properties of d33 = 271 pC/N, k p = 0.40, ε r = 1250, tan δ = 2.5%, and T c = 348 °C were fabricated. |
| Key words:
NKN ceramics · MnO2 · PZT · Perovskite · Accepter · Piezoelectric · Lead-free |
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