{'fraction_non_alphanumeric': 0.0551440329218107, 'fraction_numerical': 0.043621399176954734, 'mean_word_length': 4.735849056603773, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Control of phase transition of (K0.5Na0.5)(Nb0.8Ta0.2)O3 lead-free ceramics by alkaline metal modification

ABSTRACT (Na0.5K0.5)(Nb0.8Ta0.2)O3 lead-free ceramics with variation of alkaline metal elements were investigated. It has been found that the phase transition temperature of the ceramics can be widely adjusted by A-site doping. Li+ doping could increasing TC, while other alkaline metal elements Na+, K+, Rb+ and Cs+ doping couldn't stabilize orthorhombic phase. TC increased to 377°C from the initial 306°C as the Li+ amount increasing from 0.02 to 0.10, meanwhile, TO-T decreased from 82°C to −38°C. It is indicated that TC can be influenced by tolerance factor t. An enhanced d33 = 185 pC/N and kp = 44% at room temperature were observed in the ceramics with Li+ content of x = 0.04, probably because the corresponding TO-T of the ceramics is moved to room temperature at x = 0.04 Li+ amount. The enhanced piezoelectric properties indicate that the modified (Na0.5K0.5)NbO3 lead-free materials are promising candidates to complement Pb(Zr,Ti)O3 based solid solutions on certain occasions and the expanded phase-transition temperature range can be beneficial to the service circumstances of the materials.