湿化学法制备0.95Pb（Mg1／3Nb2／3）O3—0.05PbTiO3铁电陶瓷

用湿化学法制备了钙钛矿相的含量为９９％的０．９５Ｐｂ（Ｍｇ１／３Ｎｂ２／３）Ｏ３－０．０５ＰｂＴｉＯ３确定了０．９５ＰＭＮ－０．０５ＰＴ前驱物的最佳条件为：溶液的ｐＨ值 为１．５，反应温度为６０℃。     

MnO_2对0．85Pb（Zn_（1／3）Nb_（2／3））O_3－0．15B

研究了ＭｎＯ＿２掺杂对０．８５Ｐｂ（Ｚｎ＿（１／３）Ｎｂ＿（２／３））Ｏ＿３－０．１５ＢａＴｉＯ＿３陶瓷电、热释电以及铁电弛豫等性能的影响。添加ＭｎＯ＿２使ｐＺＮ－ＢＴ陶瓷的介电常数ε下降，室温老化率明显增大。随着ＭｎＯ＿２含量的增加，ＰＺＮ－ＢＴ陶瓷介电常数与温度的关系中所表现出来的频率弛豫现象逐渐减弱，直至消失，但其扩散相变现象仍然十分明显。     

影响（Ba_（0．65）Pb_（0．35））TiO_3系PTC陶瓷电阻率的因素

在合成的（Ｂａ０．６５Ｐｂ０．３５）ＴｉＯ３中分别掺入了Ａｌ２Ｏ３，ＳｉＯ２，Ｌａ２Ｏ３，ＭｎＯ２和ＴｉＯ２．讨论了每种掺杂物与烧成气氛和升温制度对常温电阻率的影响，找出了ＰＴＣ陶瓷的最佳组成；１ｍｏｌ（Ｂａ０．６５Ｐｂ０．３５）ＴｉＯ３，０．００２ｍｏｌＡｌ２Ｏ３，０．００４ｍｏｌＳｉＯ２，０．０１ｍｏｌＴｉＯ２，０．００３ｍｏｌＬａ２Ｏ３，０．０００２ｍｏｌＭｎＯ２．这种ＰＴＣ陶瓷的表面温度为２７０℃，常温电阻率为５～８×１０３Ω·ｃｍ，时任性为２４０ｖ／ｍｍ．     

LaCrO_3－NiMn_2O_4复合陶瓷的结构分析

将尖晶石型ＮｉＭｎ＿２Ｏ＿４及钙钛矿型ＬａＣｒＣ＿３这二者电阻个较高的半导体陶瓷热敏材料复合并经高温烧结后，其复合体电阻率大幅度降低。应用ＸＲＤ，ＸＰＳ，ＴＥＭ和ＳＥＭ对复合体结构进行较为系统的研究，结果表明：ＮｉＭｎ＿２Ｏ＿４与ＬａＣｒＯ＿３按一定比例复合后，在烧结过程中两者之间有离子迁移发生，离子迁移的结果使钙钛矿结构的ＬａＣｒＯ＿３转变为高导电相的Ｌａ［Ｃｒ＿（１－ｘ－ｙ）Ｎｉ＿ｘＭＮ＿ｙ］Ｏ＿３（０＜ｙ＜０，０＜ｘ＋ｙ＜０），它使复合体电阻率大幅度降低。     

Si_3N_4－ZrO_2陶瓷中ZrN的生成及其对性能的影响

研究了ＺｒＮ在Ｓｉ＿３Ｎ＿４－ＺｒＯ＿２复相陶瓷中的形成及其对材料性能的影响，结果表明：在１．５ＭＰａＮ２气压烧结条件下，ＺｒＮ的形成温度约为１６００℃，提高Ｎ＿２的压力有利于抑制ＺｒＮ的生成，以稳定的ｔ－ＺｒＯ＿２加Ｓｉ＿３Ｎ＿４基体中，对抑制ＺｒＮ的生成有明显作用。当复相陶瓷中生成一定量的ＺｒＮ时，力学性能明显下降，而ＺｒＯ＿２分布均匀且以ｔ－ＺｒＯ＿２，ｃ－ＺｒＯ＿２形式存在时，复相陶瓷具有较高的强度（７４０ＭＰａ）和断裂韧性（８．８ＭＰａ·ｍ￣（１／２））。     

固体电解质La_（1－x）Ca_xF_（3－x）的阻抗谱研究

在４２３～７７３Ｋ温度范围内利用阻抗谱测定了多晶固体电解质Ｌａ＿（１－ｘ）Ｃａ＿ｘＦ＿（３－ｘ）（ｘ＝０．０１，０．０３，０．０５，０．０７，０．０９）的电导率随ＣａＦ＿２含量的变化及其在不同温度区间的表现电导激活能。结果表明，掺入１％～９％（ｍｏｌ）ＣａＦ＿２的ＬａＦ＿３其电导率比ＬａＦ＿３单晶有很大提高（１０倍左右），其电导率数量级在１０￣（－４）～１０￣（－２）Ｓ·ｃｍ￣（－１）之间，其中Ｌａ＿（０．９５）Ｃａ＿（０．０５）Ｆ＿（２．９５）具有最高的电导率。     

PZN－PFN－PFW系陶瓷的介电性质和钙钛矿相的稳定作用

研究了Ｐｈ（Ｚｎ１／３Ｎｂ２／３）ｘ（Ｆｅ１／２Ｎｂ１／２）０．６４－ｘ（Ｆｅ２／３Ｗ１／３）０．３６Ｏ３（ＰＺＮ－ＰＦＮ－ＰＦＷ）系陶瓷中ＰＺＮ含量与焦录石相形成间的关系，以及少量添加剂对钙钛矿相的稳定和介电性能的影响。在该系中仅添加０．１５ｗｔ％ＭｎＣＯ３就可制备１００％钙钛矿型结构的陶瓷。文中报导了该系组成的相关系和介电性质。钙钛矿结构的陶瓷介电常数高，电容温度系数较低。     

Sm,Gd共同掺杂的CeO2基电解质性能研究

用Ｓｍ２Ｏ３和Ｇｄ２Ｏ３共同掺杂ＣｅＯ２基电解质组分（ＣｅＯ２）０．９０（Ｓｍ２Ｏ３）０．０５（Ｇｄ２Ｏ３）０．０５）,可以在较低的温度（１４００－１４５０℃）烧结并较高电导率,８００℃时电导率约为７Ｓ．ｍ＾－１。     

丙烯在SO_4~（2－）／M_xO_y固体超强酸催化剂上齐聚过程的研究

考察了丙烯在Ｍ＿ｘＯ＿ｙ固体超强酸催化剂上的齐聚过程。实验表明，催化剂的活性顺序为Ｚ＿ｒＯ＿２＞ＴｉＯ＿２，而Ｆｅ＿２Ｏ＿３催化剂几乎无活性。ＦＴ－ＩＲ表明，ＺｒＯ＿２催化剂具有超强酸的３个特征吸收峰，即１０５０、１１３０和１２２０ｃｍ￣（－１）。ＸＲＤ分析表明，ＺｒＯ＿２为非结晶态，而未浸Ｈ＿２ＳＯ＿４的ＺｒＯ＿２没有上述３个特征吸收峰，且以晶态存在。在Ｔ＝１３０℃、Ｐ＝４．０ＭＰａ、ＬＨＳＶ＝１．０ｈ￣（－１）和丙烯浓度为５０％的条件下，１００ｈ的稳定性试验表明，丙烯平均转化率为６９．５％，壬烯选择性为４５．５％和十二烯选择性为４１．６％。     

铅系复合钙钛矿Pb（Fe_（1／2）Ta_（1／2））O_3铁电陶瓷的介电弛豫

用普通合成法制备了纯钙钛矿结构相的Ｐｂ（Ｆｅ＿（１／２）＝Ｔａ＿（１／２））Ｏ＿３（ＰＦＴ）陶瓷，并进行了９００℃退火热处理。对其介电性质测试结果表明，未热处理与热处理过的ＰＦＴ陶瓷在０．１～１００ｋＨｚ频率下均表现出介电弥散性转变。未热处理的ＰＦＴ陶瓷最大介电常数对应的温度（Ｔ＿０）不随测量频率变化；热处理过的ＰＦＴ陶瓷在此频率范围Ｔ＿０值表现出明显的频率依赖性（频率色散），即ΔＴ＿０＝５℃。由此可以认为ＰＦＴ是弛豫铁电体。ＸＲＤ结果表明，未热处理的ＰＦＴ陶瓷无超晶格衍射；而热处理过的ＰＦＴ陶瓷则有较弱的（１１１）超晶格衍射。利用有序－无序转变理论及超顺电结构模型对其结构与性质进行了探讨。     

Pb(Zn_(1/3)Nb_(2/3))O_3-Pb(Fe_(2/3)W_(1/3))O_3二元系陶瓷的介电性质和钙钛矿相的形成机制

制备 Pb(Zn_(1/3)Nb_(2/3))O_3(PZN)基陶瓷电容器,最主要的问题是形成有害于介电性质的焦录石相。实验表明,固相反应法很难合成钙钛矿结构的 PZN 陶瓷,于1000经固相反应的产物是含立方焦录石的混合物,在 PZN 中添加0.53mol 的 PFW,试样中的钙钛矿相超过97%。通过对 Pb(Fe_(2/3)W_(1/3))O_3(PFW)结晶化学和烧结机理的分析,证明在 PZN 中添加 PFW 能减少或抑制焦录石的形成。本文报导了 PZN-PFW 二元系陶瓷的相关系和介电性质,探讨了钙钛矿相的形成机理。     

Dieletric and relaxation behaviors of (PbMg1/3Nb2/3O3)0.67(PbTiO3)0.33 single crystal

Dielectric permittivity along the [111] direction has been measured as a function of temperature for a relaxor ferroelectric single crystal (PbMg_1/3Nb_2/3O₃)_0.67(PbTiO₃)_0.33 (PMN-33%PT). A sharp ferroelectric phase transition was observed near 425 K and 429 K for cooling and heating processes, respectively. As temperature decreases, a diffuse phase transition (which begins near 330 K upon cooling) was detected. In addition, the nature of the thermal hysteresis for the dielectric permittivity confirms that these transitions (near 330 and 425 K upon cooling) are diffuse first-order and first-order, respectively. The frequency-dependent dielectric data ε'₁₁₁ (ƒ, T) prove the existence of an electric dipolar relaxation process between 350 and 400 K. The activation energy, the Vogel-Fulcher temperature and attempt frequency corresponding to this relaxation process are also calculated.     

(1-x)Pb(Ni1/3 Nb2/3)O3-xPbTiO3陶瓷的合成及其电滞回线

采用两步法在850℃合成了(1-x)Pb(Ni1／3Nb2／3)O3-xPbTiO3(x=0．28～0．42)陶瓷,粉末均为单一钙钛矿相。扫描电子显微镜观察和介电性能检测表明：所研究的陶瓷的最佳烧结温度为1200℃。对1200C烧结的0．64Pb(Ni1/3Nb2/3)O3-0．36PbTiO3陶瓷的铁电性能进行了详细地研究,发现组成在准同型相界的陶瓷铁电性得到增强．而这种铁电性增强正是由组分及结构和准同型相界的本质共同决定的。     

Phase transitions and domain structures in relaxor-based ferroelectric (PbZn1/3Nb2/3O3)0.915(PbTiO3)0.085 single crystal

Polarization-electric field (P-E) hysteresis loops and domain structures have been measured as a function of temperature in relaxor-based ferroelectric single crystal (PbZn_1/3Nb_2/3O₃)_0.915(PbTiO₃)_0.085 (PZN-8.5%PT). In order of increasing temperature, PZN-8.5%PT undergoes successive phase transitions: rhombohedra1 phase (below ∼375 K) → coexistence of rhombohedral and tetragonal phases (between ∼375 and ∼390 K) → tetragonal phase (between ∼390 and ∼420 K) → coexistence of tetragonal and cubic phases (between ∼420 and ∼460 K) → cubic phase (above ∼460 K). Phase coexistence suggests an inhomogeneous distribution of Ti⁴⁺ concentration in the PZN-8.5%PT crystal.     

Pb（Zn1／3Nb2／3）O3基陶瓷固相反应中的相变过程

用两次合成工艺,按Pb(Zn_(1/3)Nb_(2/3))O_3(PZN)的化学计量比合成的陶瓷为一种立方焦绿石相和PbO的混合物,其中立方焦绿石相为主晶相。该焦绿石结构的分子式为Pb_2ZnNb_2O_8,Fd3m空间群,Z=6,α=10.62(?)。在PZN基陶瓷中引入钙钛矿结构的子晶(如BaTiO_3),将促进其周围的Pb_2ZnNb_2O_8与PbO结合,形成钙钛矿结构的Pb(Zn_(1/3)Nb_(2/3))O_3。     

Phase evolution and strong temperature-dependent electrostrictive effect in (1−x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 solid solutions

(1−x)Pb(Mg_1/3Nb_2/3)-xPbTiO₃ (PMN-xPT) ceramics with x ranging from 0.1 to 0.3 were synthesized by solid-state reaction method. X-ray diffraction, dielectric and ferroelectric property characterizations were systematically investigated. As x rises, the PMN-xPT transitions from a cubic to a rhombohedral phase, resulting in an enhancement in ferroelectricity. Our findings show that the electrostrain and longitudinal electrostrictive coefficient Q₃₃ both increase and then decrease within a critical region located between the depolarization temperature T_FR and T_m (corresponding to the maximum permittivity), demonstrating strong temperature-dependent characteristics. In x = 0.2, the maximum Q₃₃ of 0.0361 m⁴/C² is obtained, and a phase diagram of studied system is built. Our findings not only shed light on the phase evolution in this system but also reveal a strong temperature-dependent electrostrictive effect that can be used to improve electrostrains in PMN-based solid solutions if the critical region can be regulated to a suitable temperature region using engineering strategies.     

Lead-reduced Bi(Ni2/3Ta1/3)O3-PbTiO3 perovskite ceramics with high Curie temperature and performance

With increasing demand of high-temperature piezoelectric devices and growing concern over environment protection, a feasible reduction in lead from lead-based high Curie temperature piezoelectric materials are desperately needed. Herein, a new system of lead-reduced Bi(Ni_2/3Ta_1/3)O₃-PbTiO₃ (BNT-PT) ferroelectric ceramics is fabricated by a conventional solid-state sintering process. The phase transition behaviors as a function of composition and temperature, electrical properties, as well as the domain configurations from a microscopic level have been investigated in detail. The results indicate that crystal structures, phase transition behaviors, and electric properties of BNT-PT ceramics can be affected significantly by the content of BNT counterpart. Dielectric measurements show that xBNT-(1−x)PT ceramics transfer from the normal ferroelectrics to the relaxor ferroelectrics at compositions of x = 0.3-0.35. The BNT-PT ceramics exhibit high Curie temperature T_C ranging from 474 to 185°C with the variation in BNT content. The relative dielectric tunability n_r also rises from only 0.65% for 0.10BNT-0.90PT to 50.23% for 0.40BNT-0.60PT with increasing BNT content. The tetragonal-rich composition 0.30BNT-0.70PT ceramic possesses the maximum remnant polarization of P_r ~ 34.9 μC/cm². Meanwhile, a highest piezoelectric coefficient of d₃₃ ~ 271 pC/N and a high field piezoelectric strain coefficient of  ~ 560 pm/V are achieved at morphotropic phase boundary (MPB) composition of 0.38BNT-0.62PT. The maximum value of strain ~0.31% is obtained in the 0.36BNT-0.64PT ceramic. The largest electromechanical coupling coefficient k_p is 44.5% for 0.37BNT-0.63PT ceramic. These findings demonstrate that BNT-PT ceramics are a system of high-performance Pb-reduced ferro/piezoelectrics, which will be very promising materials for piezoelectric devices. This study offers an approach to developing and exploring new lead-reduced ferroelectric ceramics with high performances.     

固相反应法钙钛矿型Pb（Zn1／3Nb2／3）O3的合成

用XRD法研究了八面体择位能大的离子对合成钙钛矿型Pb(Zn_(1/3)Nb_(2/3))0_3[PZN]多晶材料的影响。通过对PZN结晶化学参数的分析,认为八面体择位能大的Mn~(3 )离子能有效的抑制焦录石的形成。结果表明在PZN中添加1wt％MnCO_3就能获得完全无焦录石的钙钛矿型结构的PZN陶瓷。文中讨论了相组成和钙钛矿相的稳定机理。     

Temperature induced dielectric polarization evolution in polycrystalline Pb(Cd1/3Nb2/3)O3

The results of X-ray diffraction (XRD), scanning electron microscopy (SEM), dilatometric and dielectric measurements performed for the same polycrystalline Pb(Cd_1/3Nb_2/3)O₃ (PCN) sample are presented. These results reveal the complex character of polycrystalline PCN dielectric properties; in particular, no structural phase transition (PT) was observed. The thermal expansion coefficient indicates glass-like behaviour of PCN. The frequency and temperature dependencies of complex dielectric permittivity were measured and analyzed in terms of diffused/relaxor transition of the ferroelectric polarization. Temperature induced evolution of the relative dielectric permittivity was found to involve two processes. Dielectric permittivity changes, originating from thermally induced evolution of thermal equilibrium of interactions between main structural lattice and two sub-lattices present in the sample were interpreted in terms of thermal evolution of polar cluster sizes in the region of relaxor/glass-like transition.