双晶压电悬臂梁电荷输出特性实验研究

通过研究压电材料的压电效应与压电方程组,得到正压电效应下的压电能量采集相关知识,并分析双晶压电悬臂梁的结构与特性,结合实验与仿真,得出并联型双晶压电悬臂梁的相关输出特性。     

自悬浮线性空气轴承的理论分析和轴承设计

挤压膜的承载能力已经在理论与实验方面得到了验证,设计了一种新型的挤压膜空气轴承,可应用在直线型导轨系统中;轴承材料为航空铝型材,压电激励和弹性铰链用来引起轴承振动和产生轴承挤压膜的压力,激振频率的选择由轴承的模态主振型确定。通过ANSYS对电．固耦合结构进行的模态分析和谐响应分析,确定了所设计轴承的模态振型和压电激振时的谐响应振型。通过对理论计算和实验结果的比较,证实了此轴承应用于线型导轨的可行性。     

压电驱动膜片的弯曲振动仿真

基于压电本构方程,建立了压电弹性复合驱动膜的机电耦合模型,利用ANSYS软件对压电复合膜进行了静态及一阶模态分析,对比分析了空心与实心PZT复合膜片的驱动能力,分别讨论了复合膜厚度、压电膜与弹性膜直径比等结构参数对膜片振动挠度的影响,获得了压电层与弹性层最佳粘贴比.     

减小压电陶瓷驱动电源纹波的一种有效方法

为了解决直流放大式压电陶瓷驱动电源在实际应用中存在输出电压纹波较大且幅值随输出电压大小而改变的问题，对其工作原理进行了深入分析，在此基础上提出了采用恒流源代替基在级电路负载的方法。实验表明，这种有效地抑制了电源的纹波及其变化。     

Enhanced piezoelectricity and non-contact optical temperature sensing performance in Er3+ ion modified (K,Na)NbO3-based multifunctional ceramics

Rare earth ions doped ferroelectrics have attracted wide attentions due to their multifunction characteristics with both ferroelectric/piezoelectric properties and intriguing photoluminescence performance, which show great prospects for future multifunctional devices. In this work, a novel rare earth Er³⁺ ion modified potassium-sodium niobate (KNN) based ceramics were elaborately designed and prepared by the conventional solid-state reaction. The microstructure, phase structure, electric properties and photoluminescence performance of the Er³⁺ ion modified KNN-based ceramics were systematically investigated. Enhanced piezoelectricity (a considerable d₃₃ of exceeding 300 pC/N and a large d₃₃* up to 500 p.m./V) was realized through optimizing the substitution of BaZrO₃ by (Er_0.5,Na_0.5)ZrO₃. Both down-conversion and up-conversion photoluminescence emissions were detected in the optimal composition. The temperature-dependent upconversion emissions of the optimal Er³⁺ modified ceramic sample in the temperature range of 303–573K were verified to be applicable for non-contact optical temperature sensing with a maximum sensitivity S_a of 0.0028 K^-1 and a peak relative sensitivity S_r of 0.96% K⁻¹. Moreover, low-temperature sensing performance with a maximum S_r of 16.7% K⁻¹ in the temperature range of 80–280K was also presented based on the temperature-dependent down-conversion emissions. With both decent electrical properties and intriguing photoluminescence performance, the Er³⁺-modified KNN-based ferroelectrics exhibit good application potential in the future multifunctional optoelectronic devices.     

The effects of BaTiO3 on the handleability and mechanical strength of the prepared piezoelectric calcium phosphate silicate for bone tissue engineering

Natural bone is a piezoelectric material that can generate electrical signals when subjected to an external force. Although many studies have attempted to develop piezoelectric biomaterials for bone regeneration, post-treatment steps, such as sintering, are always needed. In this study, we prepared an injectable and piezoelectric bone substitute based on nanosized BaTiO₃ (nBT)-added calcium phosphate silicate (CPS). The impacts of nBT on the CPS handleability and mechanical strength were characterized, and show that adding nBT could improve the CPS handleability but affect the CPS mechanical strength in a concentration-dependent manner (from 25.3 ± 1.0 MPa for 10BC to 13.5 ± 1.0 MPa for 40BC). In addition, our approach could fabricate a piezoelectric bone substitute with comparable piezoelectricity to the native bone without any post-treatment. The in vitro analyses demonstrated that nBT/CPS was biocompatible and could promote osteoblast differentiation. In conclusion, our results strongly indicate that the injectable formulation based on nBT/CPS can be a promising candidate in bone tissue engineering, and further research is needed to investigate the biomaterial's performance in bone defect animal models.     

Effect of the slurry composition on the piezoelectric properties of PZT ceramics fabricated via materials extrusion 3D printing

Herein, the effect of the binder content in lead zirconate titanate (PZT) slurry has been systematically studied to improve the piezoelectric properties of PZT ceramics prepared via material extrusion 3D printing. For smooth printing, a slurry with a binder concentration ranging from 6 to 12 wt% was proposed. The porosity of the green body first decreased and then increased with an increase in the binder concentration, and the minimum porosity was obtained when the binder concentration reached 10 wt%. Samples with increased density were obtained after debinding and lead-rich atmosphere sintering. PZT piezoceramics fabricated using a binder content of 10 wt% exhibit the maximum relative density (96.9%), largest piezoelectric constant (342.6 pC/N) and dielectric constant (1621). Based on the above process, the wood pile structure and helical twentytetrahedral structural components were successfully fabricated using the material extrusion process. This research lays the foundation for the engineering application of 3D printing to fabricate high-performance piezoceramics with complex shapes.     

Investigations on electric properties and domain structures of Nd-doped 0.70Pb(Mg1/3Nb2/3)O3–0.30PbTiO3 relaxor ferroelectric ceramics with high piezoelectric properties

Although rare earth neodymium (Nd) doping is common in Pb(Mg1/3Nb2/3)O₃–PbTiO₃ (PMN–PT) single crystals, it is rarely reported in PMN–PT ceramics. To explore the effect of Nd doping on PMN–PT ceramics, PMN–30PT:xNd³⁺ (x = 0%, 1%, 2%, and 3%) relaxor ferroelectric ceramics were fabricated using a solid-state method via two-step sintering. An enhanced piezoelectric charge coefficient (d₃₃) of ∼870 pC/N and a high piezoelectric strain coefficient (d₃₃*) of ∼1025 pm/V were achieved for x = 2%. Through Rayleigh analysis of polarization–electric field (P–E) hysteresis loops under small electric fields, it was found that the dielectric property was mainly influenced by the intrinsic contribution (local lattice distortion). Furthermore, by investigating domain configurations, high piezoelectric properties were found to be associated with the domain size reduction and local structural heterogeneity. The results indicate that the PMN–30PT:xNd³⁺ ceramics is a promising material for electronic devices, and that rare earth Nd doping is an efficient strategy for improving the electronic performance of Pb-based relaxor ferroelectrics.     

Large electrostrain at high temperature in bismuth sodium titanate-based piezoelectric ceramics

(1-x)[0.82Bi_0.5Na_0.5TiO₃-0.18Bi_0.5K_0.5TiO₃]-xAgNbO₃ ceramics (abbreviated as BNKT-100xAN, x = 0–0.06) are fabricated by the solid state reaction method. It is discovered that silver niobate is completely dissolved into the lattice of 0.82Bi_0.5Na_0.5TiO₃-0.18Bi_0.5K_0.5TiO₃ ceramics based on characterization. The relaxation mechanism and characteristics of BNKT-100xAN ceramics are analyzed by dielectric temperature spectra and AC impedance spectra. The content of ordered domains and PNRs of BNKT-4AN ceramics is optimum, which enables it possess excellent electrostrain of 0.51%. The electrostrain almost remain constant after the 10⁴ cycles test, suggesting that it also has great fatigue resistance. After polarization at high temperature, large electrostrain of 1.4% and inverse piezoelectric constants of 2004 pm/V are obtained at 150 °C in BNKT-4AN ceramics. The ultrahigh electrostrain is mainly promoted by the larger polarizability of the <111>-oriented and <001>-oriented defect dipoles, the same direction of defect dipoles and the spontaneous polarization direction of phase, the pinning effects of the defect dipoles on the PNRs and the collinear arrangement of the PNRs. This work indicates that lead-free piezoelectric ceramics is hopeful to be applied in piezoelectrics working at high temperature. Simultaneously, a new design paradigm also is provided for the preparation of piezoelectric ceramics with excellent performance.     

The effect of pre-annealing on the microstructure of (K,Na)NbO3 ceramics

The effects of pre-annealing on the microstructure development and piezoelectric properties for 0.95(K_0.5Na_0.5)NbO₃–0.05LiSbO₃ (0.95KNN–0.05LS) ceramics were investigated. The pre-annealing suppressed the abnormal grain growth in both the undoped and Mn-doped 0.95KNN–0.05LS ceramics. The pre-annealed samples possessed smaller abnormal grains, larger matrix grains, and a broader grain size distribution compared to the samples sintered without a pre-annealing step. The pre-annealed samples presented better dielectric and piezoelectric properties, a larger dielectric constant (ε_r) and electromechanical coupling factor (k_p), and a smaller dielectric loss factor (tan δ).