Defect suppression in CaZrO3‐modified (K, Na)NbO3‐based lead‐free piezoceramic by sintering atmosphere control. Issue 8 (22nd February 2018)

• Record Type: Journal Article
• Authors: Thong, Hao‐Cheng; Li, Qi; Zhang, Mao‐Hua; Zhao, Chunlin; Huang, Kevin Xiu; Li, Jing‐Feng; Wang, Ke
• Is Part Of: Journal of the American Ceramic Society. Volume 101:Issue 8(2018)
• Page Start: 3393
• Page End: 3401
• Publication Date: 2018-02-22
• Subjects: defects -- ferroelectricity/ferroelectric materials -- lead‐free ceramics -- piezoelectric materials/properties -- sinter/sintering; Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.15488
• Languages: English
• ISSNs: 0002-7820

Abstract

Abstract: During high‐temperature crystal growth, lattice defects will inevitably form inside piezoelectric materials, which can be a hindrance for performance optimization. Through appropriate atmosphere control during sintering, defect levels inside the piezoelectric material can be regulated. Herein, CaZrO3 ‐modified (K, Na)NbO3 ‐based lead‐free piezoelectric ceramics with a nominal composition of 0.95(Na0.49 K0.49 Li0.02 )(Nb0.8 Ta0.2 )O3 ‐0.05CaZrO3 are produced by sintering in an oxygen‐rich atmosphere. Compared with an air‐sintered sample, the piezoelectric constant of the oxygen‐sintered sample has greatly improved 15% up to 390 pC/N, which is comparable to commercial lead‐based counterparts. In addition, the planar electromechanical coupling factor k p is enhanced from 0.46 to 0.52. A qualitative model related to defect engineering is proposed to support the experimental observations. Our results indicate the feasibility of purposely optimizing the piezoelectric performance by sintering atmosphere control.