促进PZT压电陶瓷烧结的几条途径

烧结是制备高性能PZT陶瓷的重要环节,传统固相烧结存在PbO挥发等不足.介绍了提高PZT压电陶瓷烧结性能的几种工艺技术措施,分析了各种措施的原理和特点,展望了烧结技术的发展方向,认为结合高活性粉体合成和特殊烧结手段(或装置)使用的优点用于制备性能优良的PZT压电陶瓷将是一项重要举措.     

提高PZT压电性能方法的研究现状

PZT(锆钛酸铅)是应用最广泛的压电陶瓷。介绍了提高PZT压电陶瓷压电性能的方法,重点总结了采用改变锆钛比、进行掺杂改性和调节烧结温度等方法来改变压电性能的研究现状,进而为改进工艺提高压电性能提供理论支持,并展望了将PZT压电材料应用于智能涂层在线监测的前景,分析了亟待解决的问题。     

注射法制备1-3连通压电复合材料及性能研究

采用陶瓷注射成型技术制备PZT陶瓷阵列,经过脱脂、烧结、灌注环氧树脂以及后加工得到长径比为4~5的1-3连通压电复合材料,并对其压电性能和机电转换性能进行研究。结果表明,压电系数d_(33)达到400p C/N以上,与压电陶瓷的相当;纵横耦合比k_t/k_p在2左右,高于PZT陶瓷的纵横耦合比。     

烧结温度对0.55Pb(Ni_(1/3)Nb_(2/3))O_3-0.45Pb(Zr_(0.3)Ti_(0.7))O_3压电陶瓷性能的影响

0.55Pb(Ni1/3Nb2/3)3-0.45Pb(Zr0.3Ti0.7)O3(0.55PNN-0.45PZT)组分的弛豫型压电陶瓷因具有较高的压电性能,已被作为制备含金属芯压电陶瓷纤维的材料等使用。为了进一步提高压电陶瓷纤维的电学性能,采用传统固相烧结法制备了0.55PNN-0.45PZT压电陶瓷,研究了烧结温度对材料结构、表面形貌和电学性能的影响。结果表明,在烧结温度为1200℃时,材料的各方面性能较佳:密度为8.12g/cm3,d33=850pC/N,kp=0.62,εr=7317,tanδ=0.033,Qm=41.66。     

铌锰锆钛酸铅压电陶瓷烧结行为的研究

运用XRD、SEM、TEM、XPS等实验手段,研究了烧结温度对0.05PMnN-0.95PZT (PMnN—PZT)压电陶瓷微观结构、压电性能及锰元素价态的影响.实验结果显示:随烧结温度的降低平均晶粒尺寸减小,四方度也随之减小;机电耦合系数(k_p)随烧结温度的升高而提高, 而机械品质因子(Q_m)却呈波浪状变化. XPS及TEM实验分析证明:PMnN—PZT陶瓷在烧结过程中出现明显的液相烧结和成分偏离,低温烧结诱导了Mn²⁺的出现,产生更多的氧空位,从而使低温烧结下的样品Q_m值不致降低.     

具有大驱动位移的复合结构型PZT压电陶瓷

采用PZT作为基体材料,通过化学还原的方法制备了具有大位移驱动能力的复合结构型压电陶瓷。研究了其预制应力的分布,探索了还原制备工艺,测试了驱动性能。结果表明,复合结构的优化设计方案是,还原层厚度比率为0.3;与普通压电陶瓷驱动器相比,复合结构型PZT压电陶瓷具有较低的谐振频率,驱动位移量提高3倍多;还原层相结构中存在二次氧化的基体相,表明其还原工艺仍需改进。      

0-3 PZT/PVDF 压电复合材料的制备及其性能

采用溶液混合法制备PZT/PVDF压电复合材料。首先用水热法制备出适合溶液混合的PZT陶瓷粉末,并根据陶瓷粉末对PVDF的吸收量,选择乙醇作为PVDF的溶剂进行混合,然后烘干制备PZT/PVDF复合粉末,再成型极化。实验结果表明,这种复合方法提高了PZT陶瓷颗粒在PVDF有机基体中的分散度,使材料内部均匀,结构致密,从而提高了PZT/PVDF压电复合材料的压电和介电性能。      

溶胶-凝胶法制备Na0.5Bi0.5TiO3基无铅压电陶瓷的研究进展

钛酸铋钠(Na0.5Bi0.5TiO3,简写为NBT)基无铅压电陶瓷由于具有良好的压电性、高居里温度和烧结过程中无毒、易控制性等优点而备受关注.综述了溶胶-凝胶法制备Na0.5Bi0.5TiO3粉体及制备出的陶瓷的结构和性能特点.总结了用溶胶-凝胶法制备压电和介电性能显著提高的钛酸铋钠基无铅压电陶瓷的研究进展.研究表明,溶胶-凝胶法在制备压电陶瓷方面具有均匀性好、纯度高,烧结温度低等优点.展望了该工艺的发展方向.     

超高居里温度钙钛矿层状结构压电陶瓷研究进展

钙钛矿层状压电陶瓷具有超高居里温度和高温度稳定性, 已成为目前高温压电陶瓷的研究热点。本文针对钙钛矿层状压电陶瓷致密化烧结难以及压电性能低的难题, 主要从晶体结构、制备工艺、掺杂改性和复合固溶体等方面总结了钙钛矿层状高温压电陶瓷的研究进展, 同时归纳和比较了不同制备工艺和掺杂改性的钙钛矿层状高温压电陶瓷的烧结性和压电性能。简要分析了钙钛矿层状结构自发极化的来源, 并对未来研究这类材料的铁电相变机理和提高压电性能作了展望。     

钴铁氧体/锆钛酸铅复合陶瓷材料制备及性能分析

为了得到性能优良的钴铁氧体/锆钛酸铅复合陶瓷材料,首先制备了CoFe2O4和Pb(Zr0.52Ti0.48)O3粉末,然后按照5种配比在4个温度下烧结成了CFO/PZT复合陶瓷样品。测量了烧结样品的XRD图谱、密度、SEM图像、压电性能和磁电性能,分析了CFO和PZT的配比以及烧结温度对样品性能的影响。结果表明,烧结温度升高,样品的致密度呈升高的趋势,压电性能得到改善;CFO含量越高,压电常数下降越大;直流磁场接近饱和场时,磁电转化系数最大。     

Selective laser sintering of PZT ceramic powders

Conditions for the selective laser-induced layer sintering of a stoichiometric mixture of PbO, ZrO₂, and TiO₂ powders with the formation of bulk PZT ceramic articles were studied. The laser processing allows articles of the PZT ceramics to be obtained immediately in the course of sintering or upon additional annealing. Data on the microstructure and phase composition of the synthesized PZT ceramics are presented.     

氧化物陶瓷闪烧机理及其应用研究进展

闪烧是近些年广受关注的一种电场辅助烧结技术。本文介绍了闪烧的起源与发展, 并对闪烧的基本特征进行了分析。在闪烧孕育与引发过程的研究方面, 发现了孕育阶段的非线性电导特征和电化学黑化现象, 提出了氧空位主导的缺陷机制; 在闪烧阶段的快速致密化研究方面, 提出了电场作用导致的缺陷产生和运动会在粉体颗粒间产生库仑力, 有利于烧结前期的致密化过程, 同时发现闪烧致密化过程中还伴随着金属阳离子的快速运动; 在闪烧阶段的晶粒生长和微结构演变方面, 发现了试样温度沿电流方向呈非对称分布, 试样中间位置的晶界迁移率明显提高, 提出电化学缺陷对微观结构有重大影响。基于上述研究成果, 本团队利用电场作用下出现的低温快速传质现象, 发展了陶瓷闪焊技术, 实现了同种陶瓷/陶瓷、陶瓷/金属, 甚至异种陶瓷/陶瓷之间的快速连接; 发展了陶瓷闪烧合成技术, 不仅实现了典型氧化物陶瓷的快速合成, 而且实现了高熵陶瓷和具有共晶形貌的氧化物陶瓷的快速合成; 发展了氧化物陶瓷的电塑性成形技术, 初步实现了氧化锆陶瓷低温低应力下的快速拉伸和弯曲变形。本文最后总结了闪烧机理研究面临的挑战, 并从焦耳热效应和非焦耳热效应两方面展望了闪烧的发展方向, 期望对闪烧技术在国内的发展有所裨益。     

Co-firing preparation and properties of piezoelectric ceramic/structural ceramics layered composites

Pb(Zr, Ti)O₃(PZT)-based piezoelectric ceramics and Al₂O₃-based structural ceramics were cast and co-fired to prepare a layered piezoelectric ceramic/structural ceramic composite. Considering the significant differences in sintering characteristics of PZT- and Al₂O_3-based ceramics, control of the sintering temperature and the dependence of the linear shrinkage on the solid content of the tape-casting films were systematically conducted at first. The sintering density and the interface bonding properties of the prepared composites were then investigated. The results of electrical and mechanical properties of the composite ceramics indicate: By using sintering aids, Al₂O₃ ceramic could be fully densified and co-fired with PZT ceramic at 1150 °C. Shrinkage matching during sintering was achieved by adjusting the solid contents to 45 vol.% and 65 vol.% for PZT and alumina tape-casting films. In the layered composites, Al₂O₃ structural ceramic presents an excellent mechanical property with HV hardness of 667, while the PZT functional ceramic presents d₃₃, ε_r and tanδ of 259 pC/N, 965 and 0.37%, respectively.

     

Characterization and microstructure of porous lead zirconate titanate ceramics

Porous lead zirconate titanate (PZT) ceramics are widely used because of their low acoustic impedance, high figure of merit and high hydrostatic sensitivity. In the present work, porous PZT ceramics were fabricated by incorporating polyethylene oxide (PEO) as pore-forming agent. Both PZT powder and PEO were mixed with a binder at different ratios and compaction was carried out. The samples were slowly heated to remove the pore-forming agent and binder without cracks, followed by controlled sintering and electrode forming. Samples were poled using corona poling technique. The ferroelectric properties and microstructure of the prepared ceramics were characterized. The correlation of porosity with microstructure and ferroelectric properties were discussed.     

Control of properties of PZT ceramics during liquid-phase sintering

A PZT ceramic modified by 0.4Pb-(1–x)(B₂O₃)–x(GeO₂) glass, and glass-ceramics modified by V₂O₅, have been obtained. The influence of the chemical composition of the glasses on the mechanical strength and dielectric parameters of these ceramics is investigated. The mechanical and electrical parameters of PZT ceramics are considerably improved by small additions of glass ( 1 mass %) of suitable composition. During heat treatment, the mobility of the domain walls may be changed as a result of the interaction of smelt glass with the surface layer of the crystallites (resulting from a change of V _Pb ^t" vacancy concentration in grains and decreased mechanical tension on the grain boundaries). By introducing the glass, we can decrease the porosity of the ceramics and thus decrease the attenuation of surface acoustic waves in piezoelectric filters. The origin of the liquid phase during sintering of the PZT glass-ceramics prevents PbO evaporation. This determines the preservation of the solution's stoichiometry. The glass addition leads to a decrease in the sintering temperature of PZT, which simplifies the technological process. The glass ceramics are obtained by common ceramic technology which is used for commercial piezoceramic production. The main technological problem is choosing the chemical composition and concentration of the glass and thermal process parameters.     

PZT95／5型铁电陶瓷复合烧结研究

本文研究了ＰＺＴ９５／５型铁电陶瓷的复合（层叠）烧结，Ｎｂ２Ｏ５添加剂含量不同的两组份层叠形成的复合之间存在一个扩散界在层，组成间Ｎｂ含量浓度梯度差值越大，扩散界面层厚度越大。理论分析表明，烧结工艺对扩散界面层厚度一的影响，烧结温度赵高，保温时间越长，扩散界面怪厚度越大。     

Fabrication of PZT-polymer composite materials having 3-3 connectivity for hydrophone applications

Lanthanum-modified lead zirconate titanate (PZT) powder and volatilisable polymethylmethacrylate (PMM) polymer particles have been used for fabrication of porous sintered ceramics of interconnected porosity varying from 25% to 59%. Sintered ceramics are converted into piezoelectric PZT-polymer composites by incorporating silicone rubber elastomer followed by electroding and poling. Influence of the variation of PZT-PMM ratio and sintering temperatures on the open and closed porosity of the sintered ceramics as well as volume fraction PZT in the composites has been studied and correlated for the optimization of piezoelectric properties. The PZT-polymer composites possess low density, considerably high piezoelectric voltage coefficient and considerably lower ageing characteristics and are therefore considered suitable for designing highly sensitive hydrophone systems.     

低温烧结CoFe2O4-(PZN-PZT)多铁复合材料磁电性能研究

采用传统陶瓷工艺和低温烧结制备了CoFe₂O₄-(PZN-PZT)多铁复合陶瓷, 研究了混合方式、PZT包覆和成分变化对其结构、磁性能、磁电耦合性能的影响。XRD图谱和TEM照片显示, 采用溶胶-凝胶和包覆搅拌混合的方法获得了CoFe₂O₄/PZT核壳结构粉末, 在CoFe₂O₄表面形成了10~20 nm的钙钛矿PZT壳层。EDS结果显示, 低温烧结和阻挡层可以有效抑制两相间的元素扩散。SEM照片和磁电性能结果显示, 相对未包覆研磨混合工艺, 包覆搅拌混合可以提高磁性颗粒复合含量, 获得较好烧结匹配性, 有效提高材料的磁电耦合性能。研究结果表明, 包覆搅拌混合制备体积比为4:6的CoFe₂O₄-(PZN-PZT)样品, 经1000℃烧结, 在10 kHz下获得最大磁电耦合系数(18.3 mV/(cm·Oe))。     

AlN-SiC固溶体陶瓷研究进展

评述了国内外ＡｌＮ－ＳｉＣ固体溶体陶瓷研究工作的最新进展。着重阐述了烧结工艺,包括粉体机械混合传统烧结工艺及化学活化烧结新工艺,并对其优缺点进行了评价。认为化学活化烧结新工艺是今后制备ＡｌＮ－ＳｉＣ固溶体陶瓷的发展趋势,介绍了该领域的最新发展动态。