Chen Xiaoming, Liao Yunwen
School of Materials and Energy Engineering, Guizhou Institute of Technology, Guiyang 550003, China.
College of Chemistry and Engineering, China West Normal University, Nanchong 637009, China.
Materials (Basel). 2023 Jul 29;16(15):5342. doi: 10.3390/ma16155342.
Lead-free piezoceramics of Bi(NaK)TiO with varying concentrations of x mol% AgO (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, denoted as BNKT-xA) were fabricated using the solid-state technique. An extensive investigation was undertaken to analyze the structural, piezoelectric, and dielectric properties of these piezoceramics in the presence of Ag ions. There is no evidence of any secondary solid solution in the BNKT-xA piezoceramics. The ceramics with x mol% AgO in BNKT still demonstrate the presence of both rhombohedral (R) and tetragonal (T) phases. The addition of Ag is helpful to increase the relative density of the BNKT-xA piezoceramics. It is noteworthy that the BNKT-0.3 mol% A piezoceramics show remarkable improvements in their properties ( = 147 pC/N, = 29.6%, = 1199, tan = 0.063). These improvements may be ascribed to the denser microstructure and the preservation of morphotropic phase boundaries between R and T phases caused by the appropriate addition of Ag cations. The addition of Ag results in the relaxor behavior of the BNKT-xA ceramics, characterized by disorder among A-site cations. With the increase in temperature, the value of BNKT-xA ceramics does not vary significantly in the range of 25 to 125 °C, ranging from 127 to 147 pC/N (with a change of ≤ 13.6%). This finding shows that piezoelectric ceramics have a reliable performance over a certain operating temperature range.
采用固态技术制备了不同浓度x mol% AgO（x = 0、0.1、0.3、0.5、0.7、0.9，记为BNKT-xA）的无铅Bi(NaK)TiO压电陶瓷。对这些压电陶瓷在银离子存在下的结构、压电和介电性能进行了广泛研究。在BNKT-xA压电陶瓷中没有任何二次固溶体的证据。BNKT中含x mol% AgO的陶瓷仍显示出菱方（R）相和四方（T）相的共存。银的添加有助于提高BNKT-xA压电陶瓷的相对密度。值得注意的是，BNKT-0.3 mol% A压电陶瓷在性能上有显著改善（d33 = 147 pC/N，kp = 29.6%，εr = 1199，tanδ = 0.063）。这些改善可能归因于更致密的微观结构以及由于适量添加银阳离子而保留的R相和T相之间的准同型相界。银的添加导致BNKT-xA陶瓷呈现弛豫行为，其特征是A位阳离子无序。随着温度升高，BNKT-xA陶瓷的d33值在25至125 °C范围内变化不显著，范围为127至147 pC/N（变化≤13.6%）。这一发现表明压电陶瓷在一定的工作温度范围内具有可靠的性能。
