新型铁电固溶体铌镥酸铅–铌镁酸铅–钛酸铅的制备与表征

采用二次合成法制备了纯相钙钛矿结构三元(0.7-x)Pb(Lu1/2Nb1/2)O3-0.3Pb(Mg1/3Nb2/3)O3-xPbTiO3(PLNPMN-PT)(0.38≤x≤0.46)压电陶瓷,研究了准同型相界(MPB)附近组分的介电、压电和铁电性能。XRD分析表明PLN-PMN-PT存在准同型相界,且准同型相界区域大致为0.40≤x≤0.44。MPB附近组分为0.29PLN-0.3PMN-0.41PT陶瓷具有较高的居里温度和相变温度,分别为270℃和135℃,同时该组分表现出较好的铁电压电性能,压电系数达到460 pC/N,矫顽场为14.8 kV/cm,剩余极化强度Pr为34.6μC/cm2。PLN-PMN-PT材料在压电领域具有潜在的应用前景。     

三元陶瓷Pb(In1/2Nb1/2)O3-Pb(Ni1/3Nb2/3)O3-PbTiO3准同型相界附近组分的介电、铁电和压电性能

铅基复合钙钛矿铁电材料广泛应用于机电传感器、致动器和换能器。二元铁电固溶体Pb(Ni_1/3Nb_2/3)O₃- PbTiO₃(PNN-PT)由于其在准同型相界(MPB)区域具有优异的压电、介电性能而备受关注。然而较大的介电损耗和较低的居里温度限制了其在高温高功率器件方面的应用。本研究通过引入Pb(In_1/2Nb_1/2)O₃ (PIN)作为第三组元改善PNN-PT的电学性能, 提高其居里温度; 通过两步法合成了MPB区域的三元铁电陶瓷Pb(In_1/2Nb_1/2)O₃- Pb(Ni_1/3Nb_2/3)O₃-PbTiO₃ (PIN-PNN-PT), 研究了其结构、介电、铁电和压电性能。制备的所有组分陶瓷具有纯的钙钛矿结构。随着PT含量的增加, 陶瓷结构从三方相转变为四方相。通过XRD分析得到了室温下PIN-PNN-PT体系的MPB相图。体系的居里温度由于PIN的加入得到了很大的提高, 更重要的是PIN的引入降低了PNN-PT体系的介电损耗和电导。MPB处的组分展现出了优异的电学性能, 室温下, 性能最优组分为0.30PIN-0.33PNN-0.37PT: d₃₃=417 pC/N, T_C=200 ℃, ε′= 3206, tanδ=0.033, P_r=33.5 μC/cm², E_C=14.1 kV/cm。引入PNN-PT的PIN第三组元使得体系的居里温度和压电性得到提高的同时降低了的介电损耗和电导率, 因此, PIN-PNN-PT三元铁电陶瓷在高温高功率换能器等方面具备一定的应用潜力。     

BaZrO3掺杂对(K0.49Na0.51)0.98Li0.02(Nb0.77Ta0.18Sb0.05)O3无铅压电陶瓷的结构与电性能的影响

采用固相反应法制备了(K_0.49Na_0.51)_0.98Li_0.02(Nb_0.77Ta_0.18Sb_0.05)O₃-xBaZrO₃ (NKNLST-xBZ, x = 0~0.020 mol)无铅压电陶瓷, 系统研究了BaZrO₃的掺杂量对陶瓷的压电、介电、机电和铁电性能的影响。结果表明: 随着BaZrO₃掺杂量x的增加, 陶瓷的晶体结构由正交相向四方相转变, 在x=0.005~0.008区间出现正交相与四方相两相共存的区域, 在此区域内陶瓷的晶粒变得细小且均匀, 介电损耗tanδ大幅降低, 压电常数d₃₃和平面机电耦合系数k_p增加。该体系陶瓷的介电常数ε T 33 /ε0则随着BaZrO₃的增加持续增加, 相变温度则向低温方向移动。当x=0.005时, 该组成陶瓷具有最佳的综合性能: 压电常数d33=372 pC/N, 平面机电耦合系数kp=47.2%, 介电损耗tanδ=3.1%, 以及较高的介电常数ε^T₃₃ /ε₀=1470和居里温度T_c=208℃。     

TbDyFe掺杂对(Ba_(0.85)Ca_(0.15))(Ti_(0.9)Zr_(0.08)Sn_(0.02))O_3无铅压电陶瓷组织与电性能的影响

为获得BCZTS无铅压电陶瓷优良的电性能,通过对其掺杂TbDyFe,采用传统固相烧结法制备(Ba0.85Ca0.15)(Ti0.9Zr0.08Sn0.02)O3-x TbDyFe(BCZTS-x TbDyFe)无铅压电陶瓷,分析不同TbDyFe(x=0~0.4wt.%)含量对BCZTS无铅压电陶瓷微结构、压电性能、介电性能和铁电性能的影响,并利用XRD、SEM等方法分析表征样品。结果表明:所有样品均为单一的钙钛矿结构;掺杂TbDyFe后陶瓷的晶粒尺寸变小。由介电温谱可知,掺杂TbDyFe后BCZTS体系出现介电弛豫行为。当掺杂x=0.1wt.%时,无铅压电陶瓷材料的综合性能优异:d33=500 p C/N,kp=40%,εr~5955,tanδ~1.9%,Pr=6.6μC/cm2,Ec=2 k V/cm。     

LiTaO3掺杂对K0.5Na0.5NbO3基无铅压电陶瓷性能的影响

采用传统陶瓷工艺制备了LiTaO3掺杂的K0.5Na0.5NbO3基无铅压电陶瓷(记为KNN xLT,x=0～8%(摩尔分数)),并研究了陶瓷的晶相、显微结构和压电、铁电等性能.研究结果表明,KNN xLT陶瓷的正交相-四方相准同型相界(MPB)位于4%＜x＜6%处.随着LiTaO3含量的增加,陶瓷的正交→四方结构相变温度(TO-T)向低温方向移动,而四方→立方结构相变温度(Tc)向高温方向移动.陶瓷的压电常数d33和机电耦合系数kp随LiTaO3含量的增加均先增大后减小,而剩余极化强度Pr则随之逐渐减小,矫顽场Ec逐渐增大.当x=6%时,陶瓷具有较好的压电和铁电性能:d33=190pC/N,kp=40.0%,Pr=22.0μC/cm2,Ec=1.78kV/mm,Tc=440℃.该体系陶瓷具有较高的压电常数和比较大的平面机电耦合系数,是一种应用前景良好的压电铁电材料.     

BaTiO3-ZnNb2O6陶瓷介电及储能性能研究

采用固相法制备(1-x)BaTiO₃-xZnNb₂O₆ (x=0.5mol%, 1mol%, 1.5mol%, 2mol%, 3mol%, 4mol%) (简称BTZN)陶瓷, 研究了BTZN陶瓷的烧结温度、结构、介电性能和铁电性能。BTZN陶瓷烧结温度随着ZnNb₂O₆含量增加逐渐降低。XRD结果表明当ZnNb₂O₆含量达到3mol%时出现第二相Ba₂Ti₅O₁₂。介电测试结果表明随ZnNb₂O₆含量的增加, BTZN陶瓷介电常数逐渐减小, 而介电常数的频率稳定性逐渐增强。介电温谱表明所有BTZN陶瓷均符合X8R电容器标准。BTZN陶瓷的极化强度值随着ZnNb₂O₆含量的增加逐渐降低。当x=4mol%时, BTZN陶瓷获得240 kV/cm的击穿电场和1.22 J/cm ³的可释放能量密度。     

锰掺杂Sr2-xCaxNaNb5O15（x=0.05～0.35）无铅压电陶瓷微观结构与电学性能的研究

采用传统陶瓷制备工艺制备了Mn掺杂的钨青铜结构无铅压电陶瓷Sr2-xCaxNaNb5O15+ywt%MnO2(x=0.05～0.35,y=0,0.3,0.5)(SCNN-M),并对SCNN-M陶瓷相组成、微观结构及介电、压电、铁电性能进行了研究.分析表明:Ca2+已进入Sr2NaNb5O15晶格之中形成固溶体;掺杂适量的锰,能够得到致密、单一的钨青铜结构陶瓷,有效降低烧结温度,促进晶粒长大,显著提高陶瓷的介电、压电、铁电性能.当x=0.05,添加0.5wt%的MnO2时,陶瓷具有较好的介电、压电和铁电性能:介电常数εr=2123,介电损耗tanδ=0.038,压电系数d33=190pC/N,机械品质因数Qm=1455,平面伸缩振动机电耦合系数Kp=13.4%,厚度伸缩振动机电耦合系数Kt=36.5%,剩余极化强度Pr=4.76μC/cm2,自发极化强度Ps=9.36μC/cm2,矫顽场Ec=12.68kV/cm,居里温度Tc=260℃.     

新型铁电晶体铌镥酸铅-钛酸铅的生长与性能

采用顶部籽晶法生长了一系列不同组分的高居里温度铌镥酸铅-钛酸铅[(1-x)Pb(Lu_1/2Nb_1/2)O₃-xPbTiO₃ (PLN-xPT)]铁电晶体。该晶体在三方相区域表现出典型的介电弛豫特性, 不同组分的晶体表现出了较高的居里温度; 基于介电和结构测试结果, 得到了该体系的低温二元体系相图, 在相图中存在一个准同型相界区域(MPB), 其组分位于x = 0.49~0.51; 利用偏光显微镜分析晶体电畴结构得到和X射线粉末衍射测试结果吻合的相结构; 电学性能测试结果表明不同组分的晶体性能差异较大。组分位于MPB附近的晶体表现出优异的压电性能, 如x = 0.49时, 居里温度T_c = 360℃, 压电常数d₃₃ > 1600 pC/N。处于MPB附近的晶体存在较大的矫顽E_c >10kV/cm, 一些组分晶体的三方–四方相变温度T_RT > 200℃。结果表明高的居里温度及优异的压电性能使二元铌镥酸铅-钛酸铅晶体具有更大的温度应用范围及更广阔的应用前景。     

BiYbO3固溶极限对BSPT压电陶瓷结构和电学性能的影响

采用传统固相反应法制备了yBiYbO₃-(0.36–y)BiScO₃-0.64PbTiO₃(BSYPT-0.64/y)体系压电陶瓷。X射线衍射显示BSYPT-0.64/y陶瓷体系为单一的钙钛矿结构; SEM测试结果显示当y=0.1时陶瓷表面形貌出现异常, 当y=0.14时有大量粒径为0.3~0.5 μm的细小晶粒析出在陶瓷的表面; EDS能谱分析发现细小晶粒主要成分为Bi、Yb、Ti、Sc和O, 表明BiYbO₃的含量超过10%时为BSYPT-0.64/y陶瓷体系的固溶极限区域; 通过BSYPT-0.64/y陶瓷的压电性能、铁电性能测试, 介温特性(T_c~450℃)结果分析发现当y>0.1时, BiYbO₃固溶极限析出是相对孤立的行为, 不是影响BSYPT-0.64/y的结构和电学性能的主要因素, 而其结构和电学性能的降低依赖于Sc/Pb相对含量比的降低导致组分对准同型相界的偏离。     

Er3+掺杂弛豫铁电材料PMNT的单晶生长与性能表征

按照0.71Pb(Mg_1/3Nb_2/3)O₃-0.26PbTiO₃-0.03Pb(Er_1/2Nb_1/2)O₃化学式所示组分比例, 采用分步高温固相反应合成出Er³⁺掺杂PMNT多晶, 通过熔体坩埚下降法生长出尺寸φ25 mm×100 mm的Er³⁺掺杂PMNT晶体, Er³⁺离子以三元固溶体组元方式被掺杂进入钙钛矿相铁电体晶格; 测试了Er³⁺掺杂PMNT晶片的介电、压电与铁电性能以及上转换发光性能。结果表明, Er³⁺掺杂PMNT晶体呈现跟三方相纯PMNT晶体相近的介电、压电与铁电性能; 在980 nm激发光作用下, 该掺杂晶体呈现出Er³⁺离子特有的较强上转换荧光发射, 并且极化后掺杂晶体的上转换发光强度得到增强。     

Phase-transition temperatures and piezoelectric properties of (Bi1/2Na1/2)TiO3-(Bi1/2Li1/2)TiO3-(Bi1/2K1/2)TiO3 lead-free ferroelectric ceramics.

The phase-transition temperatures and piezoelectric properties of x(Bi(1/2)Na(1/2))TiO3-y(Bi(1/2)Li(1/2))TiO3-z(Bi(1/2)K(1/2))TiO3 [x + y + z = 1] (abbreviated as BNLKT100(y)-100(z)) ceramics were investigated. These ceramics were prepared using a conventional ceramic fabrication process. The phase-transition temperatures such as depolarization temperatures T(d), rhombohedraltetragonal phase transition temperature T(R-T), and dielectric-maximum temperature T(m) were determined using electrical measurements such as dielectric and piezoelectric properties. The X-ray powder diffraction patterns of BNLKT100(y)-100(z)) show the morphotropic phase boundary (MPB) between rhombohedral and tetragonal at approximately z = 0.20, and the piezoelectric properties show the maximum at the MPB. The electromechanical coupling factor k(33), piezoelectric constant d(33) and T(d) of BNLKT4-20 and BNLKT8-20 were 0.603, 176 pC/N, and 171 degrees C, and 0.590, 190 pC/N, and 115 degrees C, respectively. In addition, the relationship between d33 and Td of tetragonal side and rhombohedral side for BNLKT4-100z and BNLKT8-100z were presented. Considering both high Td and high d(33), the tetragonal side of BNLKT4-100z is thought to be the superior composition. The d(33) and T(d) of BNLKT4-28 were 135 pC/N and 218 degrees C, respectively. Moreover, this study revealed that the variation of T(d) is related to the variation of lattice distortion such as rhombohedrality 90-alpha and tetragonality c/a.     

Pb(Mn1/3Sb2/3)0.05Zr0.47Ti0.48O3压电陶瓷的温度稳定性研究

探讨了硬性添加物MnO2、软性添加物Nb2O5和两性添加物Cr2O3对锑锰锆钛酸铅Pb(Mn1/3Sb2/3)0.05Zr0.47Ti0.48O3(简称PMSZT5)压电陶瓷的相组成及温度稳定性的影响.研究结果发现:各掺杂组成在900℃的煅烧温度下,都可以得到钙钛矿结构.随着各掺杂离子的增大,四方相含量减少,准同型相界向三方相移动.综合考虑离子掺杂对PMSZT5压电陶瓷的机电性能及温度稳定性的研究结果表明:锰过量较其它铌和铬掺杂的温度稳定性更好,机电性能最佳的PMSZT5+0.1wt%MnO2的组成,ε33T/ε0=1560,d33=350pC/N,Kp=0.63,25~80℃的fr、K31和d31平均温度系数分别为72×10-6/℃、0.027%/℃和0.100%/℃.     

CeO_2掺杂对Pb_(0.92)Sr_(0.06)Ba_(0.02)(Sb_(2/3)Mn_(1/3))_(0.05)Zr_(0.48)Ti_(0.47)O_3基压电陶瓷相结构及性能的影响

采用传统固相烧结法制备Pb_(0.92)Sr_(0.06)Ba_(0.02)(Sb_(2/3)Mn_(1/3))_(0.05)Zr_(0.48)Ti_(0.47)O_3∶xCeO_2(简称PSBSM-PZT)压电陶瓷样品。研究不同CeO_2掺杂含量对PSBSM-PZT基陶瓷样品的物相结构、微观形貌、压电及介电性能的影响。结果表明:当CeO_2掺杂量x≤0.5%(质量分数,下同)时,陶瓷样品均为纯的钙钛矿结构。随着CeO_2掺杂含量的增加,陶瓷样品中四方相结构逐渐向三方相结构转变。随着CeO_2掺杂含量的进一步增加,陶瓷中出现焦绿石相,虽然陶瓷中已经出现焦绿石相,但是样品仍没有完全转变为三方相陶瓷;CeO_2掺杂具有细化晶粒的作用,当x=0.25%时样品晶粒晶界清晰,晶粒之间的结合相对致密,晶界处气孔率低,陶瓷断裂方式以沿晶断裂为主;当x=0.25%时,陶瓷样品获得最佳的压电与介电性能:d_(33)=346pC/N,k_p=0.60,Q_m=1396,ε_r=1309,tanδ=0.474%。     

Dielectric and piezoelectric properties of PbFe1/2Nb1/2O3-PbTiO3 ceramics from the morphotropic phase boundary compositional range

Dielectric, X-ray, and piezoelectric studies of highly-resistive Li-doped (1-x)PbFe(1/2)Nb(1/2)O(3)-(x)PbTiO(3) (PFN-xPT) ceramics from the 0 ≤ x ≤ 0.2 range fabricated by solid-state synthesis and usual sintering have been carried out. Distinct anomalies of dielectric and piezoelectric parameters, corresponding to the transition between rhombohedral (monoclinic) and tetragonal ferroelectric phases, have been observed in pure PFN and PFN-xPT compositions with PbTiO(3) content up to 8 mol.%. The x,T-phase diagram of the PFN-xPT solid solution system has been constructed using these data.     

Depolarization temperature and piezoelectric properties of Na1/2Bi1/2TiO3-Na1/2Bi1/2(Zn1/3Nb2/3)O3 ceramics by two-stage calcination method

A new group of NBT-based lead-free piezoelectric ceramics, Na_1/2Bi_1/2TiO₃-Na_1/2Bi_1/2(Zn_1/3Nb_2/3)O₃, was synthesized using the two-stage calcination method and depolarization temperatures and piezoelectric properties were also investigated. The XRD analysis showed that the ceramics system had a morphotropic phase boundary (MPB) between the rhombohedral and the tetragonal structure. The highest piezoelectric properties of d ₃₃ = 97 pC/N and k _t = 0·46 were obtained near MPB compositions. Furthermore, the depolarization temperatures near MPB compositions were slightly decreased and the lowest T _d was maintained at 210°C.     

Phase-transition temperatures and piezoelectric properties of (Bi/sub 1/2/Li/sub 1/2/)TiO/sub 3/-(Bi/sub 1/2/K/sub 1/2/)TiO/sub 3/ lead-free ferroelectric ceramics

The phase-transition temperatures and piezoelectric properties of x(Bi_1/2Na_1/2)TiO_3-y(Bi_1/2Li_1/2)TiO_3-z(Bi_1/2K_1/2)TiO₃ [x + y + z = 1] (abbreviated as BNLKT100y-100z) ceramics were investigated. These ceramics were prepared using a conventional ceramic fabrication process. The phase-transition temperatures such as depolarization temperatures T_d, rhombohedral-tetragonal phase transition temperature T_R-T, and dielectric-maximum temperature T_m were determined using electrical measurements such as dielectric and piezoelectric properties. The X-ray powder diffraction patterns of BNLKT100y-100z show the morphotropic phase boundary (MPB) between rhombohedral and tetragonal at approximately z = 0.20, and the piezoelectric properties show the maximum at the MPB. The electromechanical coupling factor &33, piezoelectric constant d₃₃ and T_d of BNLKT4-20 and BNLKT8-20 were 0.603, 176 pC/N, and 171degC, and 0.590, 190 pC/N, and 115degC, respectively. In addition, the relationship between d₃₃ and T_d of tetragonal side and rhombohedral side for BNLKT4-100z and BNLKT8-100z were presented. Considering both high T_d and high d₃₃, the tetragonal side of BNLKT4-100z is thought to be the superior composition. The d₃₃ and T_d of BNLKT4-28 were 135 pC/N and 218degC, respectively. Moreover, this study revealed that the variation of Td is related to the variation of lattice distortion such as rhombohedrality 90-alpha and tetragonality c/a.     

Electromechanical properties of fine-grain, 0.7 Pb(Mg(1/3)Nb(2/3))O3-0.3PbTiO3 ceramics

A fine grain, relaxor-based piezoelectric ceramic 0.7 Pb(Mg(1/3)Nb(2/3))O3-0.3PbTiO3 (PMN-30% PT) has been investigated, which was fabricated using the columbite precursor method. The complete set of electromechanical properties of the piezoceramic at room temperature is determined using a combination of ultrasonic and resonance techniques. This fine-grain ceramic (grain size < or = 2.5 microm) exhibits ultra-high dielectric permittivity (epsilon33(T)/epsilon0 approximately 7000) and a high coupling coefficient k(33) (= 0.78). Ultrasonic spectroscopy was used to measure the dispersion of the phase velocity and attenuation for the longitudinal wave propagating in the poling direction. Lower attenuation and smaller velocity dispersion were observed compared to modified Pb(Zr(x)Ti(1-x)O3 (PZT-5H) ceramics. The measurement results show that this fine-grain PMN-30% PT ceramic is a very good material for making ultrasonic array transducers.     

镧掺杂对PZN基陶瓷的电致应变和电滞后的影响

用二次合成法制备了掺镧的ＰＺＮ基多元系陶瓷并研究了镧掺杂对该体系陶瓷的相结构、介电、电致伸缩性能及电滞回线的影响。实验结果表明,随着镧含量的增加,陶瓷的钙儋 矿相含量、介电常数、同及横向电致应变和电致伸缩系数减小,电滞效应降低即剩余极化的矫场强减小,陶瓷的介电性能的温度稳定性也得到了改善。     

Na1/2Bi1/2TiO3-BaTiO3系陶瓷压电性?及弛豫相变研究

系统研究了（１－ｘ）Ｎａ１／２Ｂｉ１／２ＴｉＯ３－ｘＢａＴｉＯ３（ｘ＝０．０２、０．０４、０．０６、０．０８、０．１０）无铅压电陶瓷系统的相界、材料压电性能,弛豫特性及相变．这个系统的陶瓷材料具有Ｋｔ／Ｋｐ较大,频率常数比较高等特点．Ｘ－ｒａｙ衍射结构分析发现此系统的相界在０．０４＜ｘ＜０．０６之间;材料的一些主要性能在相界附近达到极值．利用介电系数－温度曲线,并结合热激电流曲线对此系统的弛豫性进行研究和分析;初步研究了各配方组成的铁电－顺电的相变过程,发现在一定的组成范围内,材料在由铁电相向顺电相的转变过程中经历了一个过渡相区．