Abstract Conventional solid state sintering method was used to synthesize lead-free (Ba0.91Ca0.09Sn0.07Ti0.93)O3-xHo2O3 (x = 0, 1.2,1.4,1.6,1.8 and 2.0 mol%) ceramics. The influence on electrical properties of the system as a result of the structural and microstructural changes introduced by the incorporation of rare earth Ho3+ ions has been investigated. The X-ray diffraction analysis reveals that Ho3+ ions completely diffuse into the (Ba0.91Ca0.09Sn0.07Ti0.93)O3 lattice to form a homogeneous solid solution with a pure perovskite structure having tetragonal symmetry. Evidence of Ho3+ substituting Ti4+ via the oxygen vacancy compensation mechanism exists in the range of 0–1.6 mol % Ho content, while the self-compensation mode is the preferred mechanism beyond 1.6 mol %. The average grain size exhibits a drastic reduction from 16 μm to 0.7 μm as the Ho content increases from 0 to 1.6 mol%, followed by a slight increase at higher Ho concentration. It suggests that addition of Ho3+ inhibits grain growth in the ceramics. In the composition range studied, increasing Ho3+ content produces a gradual decrease in the relative density from 93% to 81%, room temperature dielectric constant (ert) from 3997 to 807, electromechanical coupling factor (kp) from 0.23 to 0.06, and piezoelectric charge constant (d33) from 102 to 38 pC/N. This degradation in the properties is attributed to the crystalline and microstructural changes driven by the increasing presence of Ho content in the ceramics.

中文翻译：

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晶体结构和微观结构对 Ho 掺杂无铅 BCST 压电陶瓷电性能的影响

摘要 采用常规固态烧结法合成无铅(Ba0.91Ca0.09Sn0.07Ti0.93)O3-xHo2O3 (x = 0、1.2、1.4、1.6、1.8和2.0 mol%)陶瓷。已经研究了由于掺入稀土 Ho3+ 离子而引起的结构和微观结构变化对系统电性能的影响。X 射线衍射分析表明，Ho3+ 离子完全扩散到 (Ba0.91Ca0.09Sn0.07Ti0.93)O3 晶格中，形成具有四方对称性的纯钙钛矿结构的均匀固溶体。Ho3+ 通过氧空位补偿机制取代 Ti4+ 的证据存在于 0-1.6 mol% Ho 含量范围内，而自补偿模式是超过 1.6 mol% 的首选机制。平均晶粒尺寸从 16 μm 急剧减小到 0。随着 Ho 含量从 0 mol% 增加到 1.6 mol%，7 μm，然后在较高的 Ho 浓度下略有增加。这表明添加 Ho3+ 抑制了陶瓷中的晶粒生长。在研究的组成范围内，增加 Ho3+ 含量会导致相对密度从 93% 逐渐降低到 81%，室温介电常数 (ert) 从 3997 到 807，机电耦合因子 (kp) 从 0.23 到 0.06，以及压电电荷常数 (d33) 从 102 到 38 pC/N。这种性能的下降归因于陶瓷中 Ho 含量增加引起的结晶和微观结构变化。随着 Ho3+ 含量的增加，相对密度从 93% 逐渐降低到 81%，室温介电常数 (ert) 从 3997 到 807，机电耦合因子 (kp) 从 0.23 到 0.06，压电电荷常数 (d33) 从 102到 38 pC/N。这种性能的下降归因于陶瓷中 Ho 含量增加所驱动的结晶和微观结构变化。随着 Ho3+ 含量的增加，相对密度从 93% 逐渐降低到 81%，室温介电常数 (ert) 从 3997 到 807，机电耦合因子 (kp) 从 0.23 到 0.06，压电电荷常数 (d33) 从 102到 38 pC/N。这种性能的下降归因于陶瓷中 Ho 含量增加引起的结晶和微观结构变化。