Health & Environmental Research Online (HERO)


Print Feedback Export to File
7121394 
Journal Article 
Effects of A-site ionic size on the phase transition behavior of lead-free niobate ceramics 
Yan, K; Wang, F; Chen, X; Wu, D; Zhu, K; , 
2019 
1 
Ceramics International
ISSN: 0272-8842
EISSN: 1873-3956 
ELSEVIER SCI LTD 
OXFORD 
20323-20330 
WOS:000488148100090 
Understanding the phase structure evolution is important for developing high performance lead-free piezoelectric materials. In this work, the effects of A-site ionic size of monovalent ions on the phase transition behaviors for the lead-free niobate ceramics ANbO(3) (A = Li, Na, Ag, and K) are investigated using XRD analysis and dielectric measurement. The iso-valent ionic doping restrains the relaxation behavior that usually appears in the hetero-valent ionic-doped niobate ceramics. The A-site average ionic size of RA and its ionic radius differences of Delta R-A are found to be crucial influence factors on the phase transition behaviors of the ANbO(3) ceramics. Small Li+ doping stabilize tetragonal phase of the ANbO(3) ceramics with R-A > 1.47 angstrom, but stabilize rhombohedral phase of the ones with R-A < 1.47 angstrom. On the other hand, The ANbO(3) ceramics without Li+ doping prefer to orthorhombic phase due to indistinctive ionic size differences (Delta R-A < 0.25 angstrom). Our results suggest that a certain phase and phase transition boundary could be designed by appropriate ionic doping for developing the niobate-based lead free piezoelectric ceramics.