La/Nb掺杂对Bi_4Ti_3O_(12)薄膜铁电性能和疲劳特性的影响

采用溶胶–凝胶工艺(sol–gel)在Pt/Ti/SiO2/p-Si衬底上分别制备Bi4–xLaxTi3O12和Bi4Ti3–yNbyO12铁电薄膜,研究La/Nb掺杂对Bi4Ti3O12薄膜铁电性能和疲劳特性的影响。结果表明:La/Nb掺杂均能有效改善Bi4Ti3O12薄膜的铁电性能和疲劳特性。当La摩尔(下同)掺量在0.5～0.75时,La掺杂对Bi4Ti3O12薄膜的性能改善作用最好,而且在明显提高薄膜铁电性能的同时,对薄膜疲劳特性的改善更加显著,薄膜经1010极化反转后,其剩余极化强度(Pr)仅下降5.1%。Nb掺杂对提高薄膜铁电性能的作用更加明显,Nb掺量为0.06时,Bi4Ti3–yNbyO12薄膜的Pr高达18.7μC/cm2,但Nb掺量不宜过多,当Nb掺量超过0.06以后,薄膜的铁电性能和疲劳特性均反而有所下降。     

热处理工艺对钙锶铋钛铁电薄膜性能的影响

用溶胶-凝胶法和快速退火技术在带白金电极和钛过渡层的硅片(Pt/Ti/SiO2/Si)上制备了钙锶铋钛(Ca0.4Sr0.6Bi4Ti4O15,CsBT-0.4)铁电薄膜.结果表明:退火温度及保温时间对CSBT-0.4铁电薄膜的微观结构、晶粒取向以及铁电性能的影响较大.x射线衍射谱表明:退火温度为750℃、保温时间为5min,得到的CsBT-0.4铁电薄膜样品的晶粒大小较均匀且致密性好,而且晶粒以a轴取向的球状晶粒为主,剩余极化强度(2Pr)和矫顽场(2Ec)分别为16.2 μC/cm2和130kV/cm.     

Co、Mn共掺杂铋层状Na_(0.5)Bi_(4.5)Ti_4O_(15)无铅压电陶瓷的显微结构及电性能

采用固相法制备Na0.5Bi4.5Ti4O15+x%Co2O3+y%MnCO3(NBT-CM-x)(y=0.1x)铋层状无铅压电陶瓷,研究了Co、Mn共掺杂对Na0.5Bi4.5Ti4O15陶瓷显微结构和电性能的影响。结果表明:所有样品均为铋层状结构;Co、Mn共掺杂能促进陶瓷晶粒生长;随Co、Mn共掺杂量的增加,Curie温度TC逐渐升高(均在635℃以上);Cole-Cole图出现2个圆弧,表明存在晶粒和晶界效应;适量Co、Mn共掺杂提高了Na0.5Bi4.5Ti4O15陶瓷的压电常数d33、剩余极化强度Pr、机械品质因数Qm和相对介电常数εr,降低了直流电导率σDC和介电损耗tanδ。当x=3.0时,NBT-CM-x陶瓷的综合性能最佳:d33=24pC/N,Pr=11.70μC/cm2,Qm=3 117,εr=198,tanδ=0.19%,kp=9.9%,kt=14.7%,表明该陶瓷材料具有良好的高温应用前景。     

制备工艺对溶胶-凝胶法制备BeFeO3薄膜的影响

利用溶胶-凝胶法在Pt/Ti/SiO2/Si基体上制备了BiFeO3薄膜,构架了Pt/BiFeO3/Pt电容器。对不同退火温度和保温时间制备薄膜的微观形貌和铁电性能做了研究。X射线衍射仪（XRD）结果显示,不同的退火温度和保温时间并没有改变BiFeO3（BFO）的钙钛矿结构,但温度的改变会产生不同的晶相。通过扫描电子显微镜（FE-SEM）可以观察到,随着烧结保温时间的延长,薄膜晶粒有减小的趋势。P-E曲线结果表明,BFO薄膜在外加电场较高时易击穿,难以得到清晰饱和的电滞回线。     

铈和锶复合掺杂对Bi_4Ti_(2.92)Nb_(0.08)O_(12.04)高温无铅压电陶瓷的影响

采用固相法制备了Ce和Sr复合掺杂的Bi4Ti2.92Nb0.08O12.04(BTN+0.5x%CeO2+0.5x%SrCO3,0≤x≤1.5,质量分数)铋层状高温无铅压电陶瓷,研究了不同含量的Ce和Sr掺杂对BTN系陶瓷微观结构及电性能的影响。结果表明:样品均为单一的铋层状结构相,Ce和Sr的引入明显提高了陶瓷的压电性能。当掺杂量x=0.9时,样品具有最佳性能:压电常数d33=29pC/N,平面机电耦合系数kp=8.77%,介电损耗tanδ=0.13%,剩余极化强度Pr=15.87μC·cm-2和Curie温度TC=627℃。此外,该组分陶瓷样品具有良好的压电稳定性,表明该材料在高温领域下具有良好的应用前景。     

SrBi_2Nb_2O_9织构陶瓷各向异性的电性能

以熔盐法制备的片状SrBi2Nb2O9晶粒为模板晶粒,固相法制各的SrBi2Nb2O9为基体粉料,采用模板晶粒生长技术和流延法制备了SrBi2Nb2O9织构陶瓷.研究了SrBi2Nb2O9织构陶瓷沿a-b平面方向和c方向的介电、压电及铁电性能,发现SrBi2Nb2O9织构陶瓷的性能呈现出显著的各向异性,其a-b平面方向的介电常数ε33T/ε0达186,tanδ仅有0.003,压电常数d33=13pC/N,剩余极化强度Pr=10.3iμC/cm2,矫顽场强Ec=4.6kV/mm,均明显优于C方向的电性能.     

溶胶-凝胶法制备掺钙钛酸锶铋铁电薄膜

利用溶胶-凝胶法在Pt/Ti/SiO2/Si衬底上制备了CaxSr1-xBi4Ti4O15(CxS1-xBT,x=0～1)铁电薄膜.研究了不同Ca2取代量对薄膜的微观结构、取向生长、铁电性能以及介电性能的影响.结果表明:当Ca2 取代量为x=0.4时,C0.4S0.6BT铁电薄膜样品在一定程度上沿a轴择优取向;样品致密性较好,晶粒呈球型,且大小均匀,尺寸约为100nm.C0.4S0.6BT薄膜的剩余极化强度为8.37μC/cm2,矫顽场强为72kWcm;在1 Hz～1 MHz频率范围内,相对介电常数为234～219,介电损耗为0.009～0.073.     

Sm掺杂对Ba_4La_(19.33)Ti_(18)O_(54)陶瓷结构和介电性能的影响分析

主要研究了不同Sm掺杂浓度对Ba4La19.33Ti18O54陶瓷的微波介电性能和微观结构的影响。首先利用常规固相反应技术制备了Sm含量y分别为0.0,0.1,0.3,0.5和0.7的五种Ba4(La1-ySmy)9.33Ti18O54陶瓷样品;室温下在0.3～3.0GHz频率范围内,利用网格分析仪测量了这些样品的介电常数和介电损耗因子;结果表明随着Sm掺杂含量的增大,样品介电损耗明显减小,而介电常数只有微小减少。当Sm掺杂含量y=0.5时,样品的介电性能最好。此外,还利用X射线衍射仪和扫描电子显微镜研究了样品的微观结构及随微波介电性能的变化。     

LaNiO3缓冲层厚度对Ca0.4Sr0.6Bi4Ti4O15薄膜结构和电性能的影响

利用溶胶–凝胶法在Si（100）衬底上制备了具有（110）取向的LaNiO3薄膜,然后在LaNiO3/Si（100）上制备了Ca0.4Sr0.6Bi4Ti4O15（Ca0.4Sr0.6BTi）薄膜。研究了LaNiO3缓冲层厚度对Ca0.4Sr0.6BTi薄膜结构和电性能的影响。结果表明,当引入LaNiO3厚度为250 ...     

退火温度对硅基铁电薄膜Bi_4Ti_3O_(12)晶相结构的影响

采用溶胶-凝胶(Sol-Gel)法制备铁电Bi4Ti3O12 (BIT)薄膜,研究退火温度对其微观特性的影响,以掌握制备工艺中最佳退火温度。研究表明,随着退火温度的增加,BIT薄膜的c轴取向生长更明显,晶粒尺寸增加,同时表面粗糙度增加;从退火750℃开始,晶粒开始呈棒状生长;当温度高于850℃时,薄膜的c轴生长取向增长趋势不再明显。退火时间对薄膜的相结构和生长取向没有明显影响。     

流延法制备SrBi4Ti4O15压电陶瓷

采用同相法和熔盐法（KCl-NaCl作为熔盐）合成SrBi4Ti4O15陶瓷粉体，用模板晶粒定向技术（TGG）获得具有各向异性晶粒定向排列的SrBi4Ti4O15陶瓷。实验中，着重探讨了流延成型的工艺。分析表明，以预烧温度900℃模板和900℃固相粉体在1200℃烧结合成制得的流延片的取向度（79．52％）较高，定向排列程度较高，但由于实验过程中，添加了大量有机溶剂，所以有许多缺陷存在。以900℃模板在1200℃烧结的流延陶瓷片的介电性能最好.     

SrBi2Ta2O9(SBT)铁电陶瓷的制备及性能

用固相反应法合成了SrBi2Ta2O9(简称SBT)粉体，通过冷等静压成型、无压烧结的方法，制备出SBT铁电陶瓷。采用XRD、SEM、EPMA研究了材料的物相和微观组织结构，用阻抗分析仪测试了材料的介电和铁电性能。     

SrBi_2Ta_2O_9薄膜的制备和铁电性能研究

用一种新的低温过程制备了SrBi2Ta2O9铁电薄膜。在Sol-Gel方法中用Pt/Ti/SiO2/Si作衬底,研究了薄膜的结构和电特性。SrBi2Ta2O9薄膜在淀积Pt上电极之前和之后都要退火,第一次退火在760乇氧压下600℃时退火30分钟,在第二次退火后薄膜结晶良好。     

SrBi4Ti4O15铁电陶瓷的制备工艺研究

研究了固相反应合成SrBi4Ti4O15粉末的反应过程及不同预烧温度对SrBi4Ti4O15铁电陶瓷物相结构的影响。对不同工艺条件对SrBi4Ti4O15铁电陶瓷相对密度的影响进行了讨论，确定最佳工艺条件，预烧温度900℃，烧结温度为1100℃(Al2O3埋烧)。     

Ferroelectric and photocatalytic properties of Aurivillius phase Ca2Bi4Ti5O18

Aurivillius phase Ca₂Bi₄Ti₅O₁₈ powders with micrometer size were produced by solid-state reaction. X-ray diffraction revealed that the powders had polar orthorhombic structure with space group of B2cb. Ca₂Bi₄Ti₅O₁₈ ceramic exhibited frequency independent dielectric anomaly at 774°C. The piezoelectric coefficient d₃₃ value of poled Ca₂Bi₄Ti₅O₁₈ pellets was 0.7 ± 0.2 pC/N. Both frequency independent dielectric anomaly and detectable d₃₃ value clearly indicated that Ca₂Bi₄Ti₅O₁₈ is a ferroelectric material with Curie point of 774 ℃. UV–vis absorption spectra revealed that Ca₂Bi₄Ti₅O₁₈ had a direct band gap of 3.2 eV. Photocatalytic activity of the Ca₂Bi₄Ti₅O₁₈ powders was examined by degradation of rhodamine B (RhB) under simulated solar light. 16% of RhB solution was degraded by Ca₂Bi₄Ti₅O₁₈ powders after 4 hours UV-vis irradiation. With Ag nanoparticles deposited on the Ca₂Bi₄Ti₅O₁₈ powders surface, 50% of RhB was degraded under the same irradiation condition. The fitted degradation rate constant of Ag decorated Ca₂Bi₄Ti₅O₁₈ was 4 times higher than that of bare Ca₂Bi₄Ti₅O₁₈. This work suggested that the Aurivillius ferroelectric Ca₂Bi₄Ti₅O₁₈ is a promising candidate for photocatalytic applications.     

水热法制备钛酸铋粉体的研究

以TiCl4乙醇溶液和Bi（NO3）3·5H2O为原料．NaOH为矿化剂，其摩尔配比的关系为TiCl：Bi（NO3）3·5H2O：NaOH=0．1：0．75：1．5．用水热法合成钙钛矿结构的钛酸铋粉体。讨论了水热合成条件（前驱物和粉体处理、晶化时间、填充率）对钛酸铋粉体结构和形貌的影响。XRD、SEM分析表明，在240℃，晶化时间16h，填充比为60％的条件下，可制备平均晶粒粒径为9～12nm，团聚较轻，颗粒边界明显．球形的钛酸铋粉体。     

Enhanced piezoelectric performance in Na0.5Bi4.5Ti4O15-based bismuth-layered ceramics by Nb/Mn doping modification

In this work, Na_0.5Bi_4.5Ti_3.94–xMn_0.06Nb_xO_15+y bismuth-layered ferroelectric ceramics were prepared by a solid-state reaction method. The effect of Nb⁵⁺ content on crystal morphology, electrical properties, and piezoelectric performance were systematically investigated. The results show that the introduction of Nb⁵⁺ into Na_0.5Bi_4.5Ti_3.94–xMn_0.06Nb_xO_15+y ceramics to replace Ti⁴⁺ increases the ratio of b/a lattice parameter, leading to the TiO₆ octahedral distortion and the structural transformation tendency from the orthorhombic to tetragonal phase, which facilitates dipole movements of Na_0.5Bi_4.5Ti_3.94–xMn_0.06Nb_xO_15+y ceramics. Therefore, the ferroelectric properties of Na_0.5Bi_4.5Ti_3.94–xMn_0.06Nb_xO_15+y ceramics are improved, and an enhanced piezoelectric coefficient of 30 pC/N combining great temperature stability with d₃₃ value higher than 25 pC/N in the temperature range of 25°C–450°C has been realized in Na_0.5Bi_4.5Ti_3.94–xMn_0.06Nb_xO_15+y ceramics with x = 0.08 mol. Our work provides a good model for designing lead-free ultrahigh Curie temperature piezoelectric devices that can be practically applied in extremely harsh environments.     

Nb5+掺杂改性CaBi4Ti4O15压电陶瓷的研究

采用传统固相烧结法,制备了CaBi4Ti(1-x)NbxO1(5x=0.00-0.05,CBT-N)系铋层状结构无铅压电陶瓷。研究了Nb5+掺杂对CBT压电陶瓷压电与介电性能的影响。研究结果表明:添加Nb5+离子,改善了CBT陶瓷的烧结特性,提高了瓷体的致密度。Nb2O5的引入降低了CBT系列陶瓷的介质损耗,改善了陶瓷的压电与介电性能。当掺入量x=0.04(CaBi4Ti0.96Nb0.04O15)时制备的CBT基铋层状压电陶瓷具有优异的压电性能:d33=14pC/N,Qm=3086,εr=212,tanδ=0.0041,kt/kp=1.681。     

Interfacial reactions between Ti and Y2O3/Ca4Ti3O10 composites

In titanium casting, the interfacial reactions between selected Y₂O₃/Ca₄Ti₃O₁₀ composites in contact with titanium at 1600°C for 30 minutes in an argon environment were characterized using X-ray diffraction, scanning electron microscopy, and analytical transmission electron microscopy. Before contact with titanium, reaction phases of the Y₂O₃/Ca₄Ti₃O₁₀ composites formed through hot pressing at 1500°C or annealing at 1600°C. These phases were identified as Ca₄Ti₃O₁₀, Y₂O₃, and minor amounts of CaO. The amount of Ca₄Ti₃O₁₀ in the composites gradually decreased as the amount of Y₂O₃ increased. When the Y₂O₃/Ca₄Ti₃O₁₀ composites were in contact with titanium, a reaction layer of α-Ti and Y₂O₃ was formed near the interface of the composite side. Large amounts of calcium and oxygen were expelled toward the composite side from Ca₄Ti₃O₁₀ near the interface to form CaO, which precipitated in the Ca₄Ti₃O₁₀ and Y₂O₃ phases. Furthermore, no reaction phases were detected in titanium. Ca₄Ti₃O₁₀ and Y₂O₃ can function as diffusion barrier layers to effectively suppress the diffusion of oxygen into titanium.