0．992K0．5Na0．5NbO3-0．008BiFeO3无铅压电陶瓷制备及压电性能研究

以水热法制备的0．992K0．5Na0．5NbO3（BF）粉体等为原料,采用常压烧结法在1065℃下烧结2h制备了0．992K0．5Na0．5NbO3-0．008BiFe03无铅压电陶瓷,并研究了BiFeO3掺杂对0．992K0．5Na0．5NbO3-0．008BiFeO3无铅压电陶瓷结构和压电的影响．研究结果表明：BiFeO3掺杂使K0.5Na0.5NbO3无铅压电陶瓷正交相减弱,晶粒尺寸由6／2m减小到1μm;压电性能有一定提高,压电常数（d33）、机电耦合系数（kp）分别达到120pC／N和37．8,居里温度Tc由444．4℃减少至420．6℃．     

Li元素对Bi0.5Na0.5TiO3基无铅压电陶瓷压电性能的影响

针对目前无铅压电陶瓷的压电常数d33偏小的情况,采用传统的固相反应烧结方法制备得到了高压电性能的Bi0.5Na0.5TiO3基无铅压电陶瓷Bi0.5(Na0.7K0.3-xLix)0.5TiO3(x=0.04,0.08,0.12,0.16,0.20),研究了Li元素的添加量对陶瓷的烧结温度以及压电性能的影响.研究结果表明,Li元素对K的替代可以降低陶瓷的烧结温度,提高样品致密度,适量的Li可以大幅度提高陶瓷的压电性能.陶瓷样品的压电常数d33和平面机电耦合系数kp随着Li含量的增加先增大后减小,在1 090 ℃的烧结温度下,Li含量x=0.08时的陶瓷样品表现出最佳的压电性能,压电常数d33=212 pC/N,平面机电耦合系数kp=33%.     

（0.82-x）Bi0.5Na0.82Ti O3-0.18Bi0.5K0.18TiO3-xBiFeO3（x=0.01-0.07）无铅压电陶瓷的制备及其电学性能的研究

采用传统的固相烧结法于1120℃烧结2 h得到（0.82-x）Bi0.5Na0.82Ti O3-0.18Bi0.5K0.18TiO3-xBiFeO3（x=0.01-0.07）无铅压电陶瓷,并对该体系陶瓷的微观结构和电学性能进行了研究。结果表明,BiFeO3的引入量x为0.01-0.07时,样品均为具有MPB准同型相界（三方相和四方相共存）的钙钛矿结构。BiFeO3的引入使陶瓷的晶粒度略有增加;当x=0.03时,样品达到最大致密度。为97.7%;陶瓷的压电常数d33随BiFeO3的引入而降低。陶瓷的相对介电常数εr和居里温度随BiFeO3的引入而明显增大,在x=0.03时达到最大值。     

(Na_(0.5)K_(0.5))NbO_3基无铅压电陶瓷压电常数的研究

针对目前无铅压电陶瓷的压电常数d33偏小的情况,采用传统的烧结方法制备了(Na0.5K0.5)NbO3基无铅压电陶瓷(Na0.5K0.45Li0.05)Nb0.95-xSbxTa0.05O3(x=0.03,0.06,0.09,0.12),研究了在Li和Ta含量固定的情况下,Sb元素的添加量和烧结温度对陶瓷的压电常数的影响.研究结果表明,适量Sb元素的掺杂可以大幅度提高陶瓷的压电常数d33,陶瓷样品的压电常数d33随着Sb含量的增加先增大后减小.烧结温度可以影响陶瓷的密度,进而影响其压电常数.在1130℃的最佳烧结温度下,Sb含量x=0.09时,陶瓷样品表现出最佳的压电性能,压电常数d33=328 pC/N.     

PZT-PZN-NaNbO3压电陶瓷的结构和性能

对（1-x）Pb0.95Sr0.05[（Zr0.54Ti0.46）0.9（Zn1／3 Nb2／3）0.10]O3＋xNaNbO3（简称PZT-PZN-XaXbO3）压电陶瓷的结构和性能进行了研究。结果表明，随着NaNbO3掺入量的强加，d33，Kp和介电常数εr同步增加，当添加2.5mol％NbNaO3时，材料的晶体结构由三方相向四方相转变，在准同型相界处，d33和Kp以及介电常数εr达到最大值，继续增加NaNbCO3掺入量，d33，Kp和介电常数εr开始下降；NaNbO3还可以促进陶瓷烧结，降低烧结温度；通过NaNbO3掺杂改性，得到了d33=510PC/N，Kp=0、62，εr=2600，tanδ=0．024的压电陶瓷。     

Bi0．5Na0．5TiO3无铅压电陶瓷的结构有序化控制

以片状SrTiO3晶粒作为模板,使用模板晶粒生长法（TGG）控制制备[001]取向的有序化Bi0.5Na0.5TiO3压电陶瓷,同时研究了过量Bi2O3烧结温度以及掺MnO对Bi0.5,Na0.5TiO3有序度的影响．研究结果表明,过量Bi2O3的最佳掺入量为BNT粉料质量的1％;1190℃是合适的烧结温度,在1190℃下,BNT-1试样的有序度相对较高,有序度为88．2％;MnO的加入有效地提高了试样的有序度,并且降低了试样的烧结温度,同时也使得烧结温度范围变窄．在烧结温度为1170℃下,掺质量分数为0．3％MnO的BNT-1试样的有序度为91．1％．     

二次烧结对KNN-LS-Bi(Mg0.5Ti0.5)O3无铅压电陶瓷性能的影响

采用传统固相烧结法和二次烧结工艺制备了xBi(Mg0.5Ti0.5)O3-0.95K0.5Na0.5NbO3-0.05LiSbO3(xBMT-KNN-LS)无铅压电陶瓷,研究了二次烧结工艺对xBMT-KNN-LS陶瓷性能的影响。结果表明:采用传统的陶瓷烧结工艺所得到的性能为压电常数d33=220 pC/N、平面机电耦合系数kp=39.6%、介电损耗tanδ=6.38%。而采用二次陶瓷烧结工艺得到的最佳性能为d33=254 pC/N、kp=37.8%、tanδ=4.81%,因此,二次烧结对该体系的压电性能有显著的影响。     

PFW—PZT压电陶瓷性能的研究

用传统固相法制备了PbZrO3-PbTiO3-Pb(Fe2/3)O3(简称PZT-PFW)三元系压电陶瓷.研究了不同含量的Pb(Fe2/3)O3(简称PFW)对PZT-PFW陶瓷的相结构、密度、介电性能和压电性能的影响.另外,还研究了烧结温度对陶瓷电性能的影响.结果表明,PFW的加入可以降低PZT的烧结温度.当加入4.5 mol%Pb(Fe2/3)O3并在1100℃下烧结时,材料具有良好的综合电性能:d33=381pC/N,Kp=0.58,Qm=1025,tanδ=0.015,εr=1323.     

固相法和水热法制备BNT无铅压电陶瓷及其性能表征

采用固相法和水热法成功制备出钛酸铋钠（Bi0.5Na0.5TiO3,简写为BNT）粉体,并利用此粉体烧结出致密的BNT陶瓷.用XRD、SEM分别对粉体和陶瓷的相组成、粒度、显微结构等进行了表征,并检测了其不同烧结温度下的线收缩率和相对体积密度.固相法所制备的BNT陶瓷具有优良的压电性能,其压电常数d33高达80 pC/N,而机电耦合系数kp也达到了26%.利用水热法只需在160℃下保温16 h就合成了具有单一钙钛矿结构的BNT粉体,其粒径为0.6-1μm.     

钡钙锶共掺杂钛酸铋钠无铅压电陶瓷的制备及性能

采用溶胶-凝胶法制备工艺制备了（1-x）（Na0.5Bi0.5）TiO3-xBa0.092Ca0.03Sr0.05TiO3（x=0.04、0.06、0.07、0.08）系无铅压电陶瓷。研究了陶瓷的铁电、压电性能和显微结构。结果表明,该体系陶瓷在x=0.06时,其压电常数d33,机电耦合系数kp,厚度耦合系数kt,相对介电常数rε,介质损耗tgδ,分别为152,0.24,0.47,1 250,0.04。     

Synthesis and Piezoelectric Properties of Lead-free (Bi_(0.5)Na_ (0.5))_ 1-x(Ba_aSr_b)_xTiO_3 Ceramics

planarelectromechanicalcouplingfactor;piezoelectricchargeconstant1Introduction Leadoxide basedpiezoelectricceramics,suchasPb(Ti,Zr)O3(PZT),arenowwidelyusedinvariousappli cationssuchastransducers,filters,oscillatorsandactua torsbecauseoftheirsuperiorpiezoe…     

Synthesis and Piezoelectric Properties of Lead-free （ Bi0.5 Na0.5 ）1-x（BaaSrb）xTiO3 Ceramics

A new group of lead-free piezoelectric ceramics,（Bi0.5 Na0.5）1-x（BaaSrb）xTiO3（abbreviated as BNBST[100x-100a/100b],0〈x〈1,a＋b=1）,was synthesized.The ceramics were prepared by conventional ceramic sintering technique,and the ceramics with density of 95% of the theoretical one can be sintered without the atmosphere control during the sintering process.The results of the X-ray diffraction（XRD） data show that the ceramics possess a single perovskite phase.The measurements of dielectric and piezoelectric properties reveal that the ceramics provide relatively high piezoelectric charge constant d33 and high planar electromechanical coupling factor kp.For the BNBST6-95/5 ceramics,d33 is equal to 170pC/N,and kp is equal to 32.0%.The fabrication technique for these ceramics is conventional and stable.     

SCNN无铅压电陶瓷的制备和特性研究

为制备高性能的无铅压电陶瓷,在传统工艺下,制备了Ca_xSr_(2-x)NaNb_5O_(15)陶瓷各组分的样品,研究了压电介电性能随组分的变化.结果表明:在x=0.14附近Ca_xSr_(2-x)NaNb_5O_(15)材料具有较好的压电和介电性能.该材料有2个相变点,一个接近280℃,另一个在-20℃附近,具有明显的介电弛豫现象.X射线衍射和Raman光谱实验表明该材料是四方钨青铜结构,Ca~(2+)替代Sr~(2+)引起了晶格畸变,从而导致物理性能的提高.电镜扫描照片显示瓷体致密.     

Enhanced piezoelectric properties of Nd^3＋ doped nano-lead zirconate titanate piezoelectric ceramics

Nd^3＋ doped lead zirconate titanate （Pb1-3x/2NdxZr0.52Ti0.48O3, PNZT） nanopowders were prepared through a modified sol-gel method. The effects of Nd^3＋ doping on the microstructures and properties of PNZT ceramics have been studies. The grain sizes of the perovskite PNZT nanopowders were about 100nm and the lattice distortion of the PNZT increased with the content of Nd^3＋ up to 9 mol%. The dopant of Nd^3＋ resulted in the decrease of crystal lattice parameter a and the obvious increase of c and c/a, which effectively improved the sintered densification and activity of the PNZT ceramics. Due to lead vacancies caused by the doping of Nd3^＋ in the PZT, the piezoelectric constant, electromechanical coupling coefficient and dielectric constant observed were much higher than the monolithic PZT.     

Microstructure, crystalline phase and electrical properties of Li0.06（Na0.5K0.5）0.94Nb（1-2x/5）MgxO3 lead-free piezoelectric ceramics

MgO-modified Li0.06(Na0.5K0.5)0.94NbO3(L6NKN) lead-free piezoelectric ceramics were synthesized by normal sintering at a relatively low temperature of 1000°C.The crystalline phase,microstructure,and electrical properties of the ceramics were investigated with a special emphasis on the influence of MgO content.The addition of MgO effectively improves the sinterability of the L6NKN ceramics.X-ray diffraction analysis indicates that the morphotropic phase boundary(MPB) separating orthorhombic and tetragonal ph...     

Effect of Li content on the microstructure and properties of lead-free piezoelectric （K0.5Na0.5）1-xLixNbO3 ceramics prepared by SPS

Lead-free piezoelectric （K0.5sNa0.5）1-xLixNbO3 （x = 0at%-20at%） ceramics were synthesized by spark plasma sintering （SPS） at low temperature and the effects of LiNbO3 addition on its crystal structure and properties were also studied. When the Li content was less than 6at%, a single proveskite phase with the similar structure of （K0.5Na0.5）NbO3 was formed; and a secondary phase with K3Li2Nb5O15 structure was observed in the 6at% 〈 x 〈 20at% compositional range. Furthermore, LiNbO3 existed as the third phase when the Li content was higher than 8at%. The grain sizes increased from 200-500 nm to 5-8 μm when the K3Li2Nb5O15 and LiNbO3 like phases were formed. With increasing Li content, the relative density of the ceramics first decreased from 97% to 93% and then kept constant. The piezoelectric coefficient d33, dielectric constant, and planner electromechanical coupling factor exhibited a decreasing tendency with increasing Li content because of the decrease in density and the formation of the secondary phase such as K3Li2Nb5O15 and LiNbO3. The formation of dense microstructure with a single phase is necessary in improving the properties of the （K0.5Na0.5）1-xLixNbO3 ceramics.     

Effect of doped Mn on piezoelectric properties of (Na_(0.5)Bi_(0.5))_ (0.92)Ba_(0.08)TiO_3 lead-free ceramics

1INTRODUCTION Therehasbeengreatinterestinthestudiesof thelead freematerialswithdielectric,piezoelectricandferroelectricpropertiesinthefieldoffunction almaterialsfortheiramiabilitytoenvironment. (Na1/2)TiO3(NBT)ceramicshavebeenwidelystudiedbecauseoftheirrelativelylargeremnant polarization(Pr)of38μC/cm2andcoercivefieldof 73kV/cm[1].However,NBTcannotreplacelead zirconatetitanate(PZT)basedceramicsbecausethepiezoelectricpropertiesofNBTarestillnot comparabletothoseofPZT[24].Recently,m…