Electromechanical properties of Pb(In(1∕2)Nb(1∕2))O(3)-Pb(Mg(1∕3)Nb(2∕3))O(3)-PbTiO(3) single crystals

The Pb(In(1∕2)Nb(1∕2))O(3)-Pb(Mg(1∕3)Nb(2∕3))O(3)-PbTiO(3) (PIN-PMN-PT) crystals were studied as function of phase and orientation. The properties, including the Curie temperature T(C), ferroelectric-ferroelectric phase transition temperature T(R∕O-T), coercive field, and piezoelectric∕dielectric responses, were systematically investigated with respect to the composition of PIN-PMN-PT crystals. The Curie temperature T(C) was found to increase from 160 to 220 °C with ferroelectric-ferroelectric phase transition temperature T(R-T) and T(O-T) being in the range of 120-105 °C and105-50 °C, respectively. The piezoelectric activity of PIN-PMN-PT crystals was analyzed by Rayleigh approach. The ultrahigh piezoelectric response for domain engineered [001] (1600-2200 pC∕N) and [011] (830-1550 pC∕N) crystals was believed to be mainly from the intrinsic contribution, whereas the enhanced level of piezoelectric and dielectric losses at the compositions around morphotropic phase boundaries (MPBs) was attributed to the phase boundaries motion.     

La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)-Ce_(0.9)Gd_(0.1)O_(1.95)高温电导弛豫的研究

通过直流四端法研究了钙钛矿型混合导体La0.6Sr0.4Co0.2Fe0.8O3-δ(LSCF)和La0.6Sr0.4Co0.2Fe0.8O3-δ-Ce0.9Gd0.1O1.95(LSCF-GDC)复合材料的高温电学性质.通过电导率测试得出单相LSCF和LSCF-GDC的小极化子导电活化能分别为Ea1=9.72kJ/mol和Ea2=10.64kJ/mol.突然改变氧分压条件进行电导弛豫测试,进而研究了二者的氧表面交换性质.测定了温度范围在600~800℃、氧分压在21~34kPa之间变化时两种样品的表面交换系数为kchem为2.87×10-6~6.91×10-6cm/s.讨论认为GDC对氧表面交换过程的催化作用与引入GDC对材料微结构的影响共同促进了复合材料中的氧输运过程.根据两种样品氧表面交换系数和温度的关系估算了氧表面交换过程活化能.     

Investigation of single and multidomain Pb(In(0.5)Nb(0.5))O(3)-Pb(Mg(1∕3)Nb(2∕3))O(3)-PbTiO(3) crystals with mm2 symmetry

The piezoelectric properties of Pb(In(0.5)Nb(0.5))O(3)-Pb(Mg(1∕3)Nb(2∕3))O(3)-PbTiO(3) crystals with various engineered domain configurations were investigated. Rhombohedral and monoclinic∕orthorhombic crystals poled along their crystallographic [011] directions were found to possess macroscopic mm2 symmetry, with "2R" and "1O" domain, respectively. Crystals with the "2R" domain configuration were found to exhibit high extensional piezoelectric coefficients d(33) (～1300 pC∕N) and d(32) (～-1680 pC∕N), while crystals with the "1O" configuration possessed high shear coefficients d(15) (～3500 pC∕N) and d(24) (～2070 pC∕N), with relatively low extensional piezoelectric coefficients d(33) (～340 pC∕N) and d(32) (～-260 pC∕N). The observed results were explained by "polarization rotation" model, as related to their respective domain configurations.     

Co基非晶态Fe_(5.3)Co_(61.3)Ni_(7.4)Si_(10)B_(16)及Fe_5Co_(58)Ni_(11)Si_(10)B_(16)合金的磁场热处理效应

本文对Co基非晶Fe_(5.3)Co_(61.3)Ni_(7.4)Si_(10)B_(16)及Fe_(5)Co_(58)Ni_(11)Si_(10)B_(16)合金用不同方法进行了热处理后得出:退火使合金磁性恶化,纵向磁退火有效地消除了应力,局部感生各向异性和畴壁钉扎,形成感生单轴各向异性,静态磁性获得显著提高。Fe_(5.3)Co_(61.3)Ni_(7.4)Si_(10)B_(16)合金最好静态磁性μ_m高达169×10~4Gs/Oe,Hc为4.3mOe,μ_(0.002)为94000G/0e,Br/Bs=0.895,磁滞损耗减小。但由于形成粗大180°畴使反常涡流损耗增加。倾斜磁场退火使180°畴数目增多,在一定频段内有效的降低反常涡流损耗。对提高初始导磁率有一定作用。     

各向异性Nd_(12.5)Fe_(68.9-x)Co_(12)Ga_xZr_(0.1)B_(6.5)磁粉研究

采用d-HDDR(室温吸氢后"氢化—歧化—脱氢—再复合")工艺制备Nd12.5Fe68.9-xCo12GaxZr0.1B6.5(x=0,0.1,0.3,0.5,0.7)永磁磁粉,研究了歧化氢压、脱氢再复合温度、脱氢再复合真空度及合金元素Ga对Nd12.5Fe68.9-xCo12GaxZr0.1B6.5合金磁性能的影响规律,利用X射线衍射仪(XRD)对磁粉的相结构进行表征。结果表明,d-HDDR工艺中,合金的相变过程为:Nd2(Fe,Co)14B+2H22NdH2+12α-(Fe,Co)+(Fe,Co)2B;0.03MPa的歧化氢压是NdFeB磁粉产生磁各向异性的关键,脱氢再复合阶段采用高温,低真空与高真空相结合的制度是NdFeB磁粉获得高各向异性的保证;添加Ga元素有益于提高磁粉的矫顽力和各向异性,其最佳添加量为0.3%(原子分数),Nd12.5Fe68.6Co12Ga0.3Zr0.1B6.5磁粉的典型性能为:(BH)max=218.3kJ/m3,Br=1.22T,jHc=751.2kA/m,DOA=0.52。     

国际标准(ISO)题录(下)

为便于读者收集、检索国际标准化组织(ISO)发布的标准,本刊将在第三、四两期连载国际标准(ISO)题录,题录刊载了截止2002年12月中国标准研究中心标准錧收藏的全部现行标准。本刊同时发行: 国际标准化组织(ISO)标准题录(电子版)单价100.00元国际标准化组织(ISO)标准题录(中文合订本)单价150.00元上述电子版及中文合订本增加有标准顺序号与TC分类号对照表,便于读者使用。请需要的读者按杂志地址(或电话)与杂志社联系。     

Domain size engineering in tetragonal Pb(In(1∕2)Nb(1∕2))O(3)-Pb(Mg(1∕3)Nb(2∕3))O(3)-PbTiO(3) crystals

The effect of domain size on the dielectric and piezoelectric properties of [111]-oriented tetragonal Pb(In(1∕2)Nb(1∕2))O(3)-Pb(Mg(1∕3)Nb(2∕3))O(3)-PbTiO(3) crystals was investigated. The dielectric permittivity (?(33?) (T)∕?(0)) and piezoelectric coefficient (d(33)) were found to be on the order of 13 800 and 1630 pC∕N, respectively, for samples with domain size of ～500?nm, a 3-fold increase to crystals with domain size of ～50?μm. Rayleigh analysis revealed that the extrinsic contribution to the piezoelectric response increased from ～8% to 30% with decreasing domain size, due to the increased domain wall density and associated irreversible domain wall motion. The enhanced properties were thought to relate to the fine domain structures, however, showing a poor electric field and temperature stabilities with domain size of 500?nm. Of particular significance is that samples with domain size being on the order of 5?μm exhibit field and temperature stabilities, with yet high piezoelectric properties, make it potential for transducer applications.     

(1-x)(K_(0.5)Na_(0.5))NbO_3-x(Sr_(0.4)Ba_(0.6))_(0.7)Bi_(0.2)TiO_3无铅铁电陶瓷介电性能研究

采用传统固相烧结法,在铌酸钾钠陶瓷基体中掺入Sr、Ba、Bi和Ti元素,制备了(1-x)(K0.5Na0.5)-NbO3-x(Sr0.4Ba0.6)0.7Bi0.2TiO3((1-x)KNN-xBSBT)(0.01≤x≤0.04)陶瓷。XRD测试结果表明,(1-x)KNNxBSBT(0.01≤x≤0.04)为纯钙钛矿相;介电温谱表明,(1-x)KNN-xBSBT为弛豫铁电体;0.97KNN-0.03BSBT陶瓷介电常数具有很好的温度稳定性,在室温至400℃介电常数变化很小。     

Thermal Stability of Amorphous Hydride Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45)

The thermal stability of amorphous ternary hydrides Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45) and their corre-sponding amorphous binary alloys Mg_(50)Ni_(50) and Mg_(30)Ni_(70) were studied with X-ray diffraction(XRD) and differential scanning calorimetry(DSC). Samples of the amorphous alloys were preparedby mechanical alloying and the amorphous hydrides were obtained by charging the alloys with gas-eous hydrogen at 3.0 MPa and 423 K. It was found that the amorphous hydrides released most oftheir hydrogen before the crystallization of the essentially hydrogen depleted amorphous alloy. Thecrystallization temperature of amorphous Mg_(50)Ni_(50)H_(54) elevated and that of amorphousMg_(30)Ni_(70)H_(45) did not change in relation to the original binary amorphous alloy. This is very excep-tional for amorphous hydrides. The reason for the effects of hydrogen absorption/desorption on thecrystallization of amorphous alloys was discussed.     

国际标准(ISO)题录(上)

为便于读者收集、检索国际标准化组织(ISO)发布的标准,本刊将在第三、四两期连载国际标准(ISO)题录,题录刊载了截止2002年12月中国标准研究中心标准馆收藏的全部现行标准。本刊同时发行: 国际标准化组织(ISO)标准题录(电子版)单价100.00元国际标准化组织(ISO)标准题录(中文合订本)单价150.00元上述电子版及中文合订本增加有标准顺序号与TC分类号对照表,便于读者使用。请需要的读者按杂志地址(或电话)与杂志社联系。     

国际标准(ISO)题录(下)

为便于读者收集、检索国际标准,本刊在2004年第4、5期连载国际标准(ISO)题录,题录刊载了截止2003年12月中国标准化研究院标准馆收藏的全部现行标准。本刊同时发行:国际标准(ISO)题录(中文电子版)单价200.00元,国际标准(ISO)题录(中文合订本)单价200.00元。上述电子版用微软Excel软件格式排列,便于读者使用。请需要该题录或标准全文的读者按杂志地址(或电话)与杂志社联系。     

Phase Relationship in (Dy_(0.65)Tb_(0.25)Pr_(0.1))Fe_x Alloys (1.6≤x≤2.1)

The microstructure and phase relationship of (Dy0.65Tb0.25Pr0.1)Fex alloys in the composition range of 1.6≤x≤2.1 were investigated using optical microscopy, X-ray diffraction , DTA and EPMA techniques. The variations of microstructure and lattice parameter with the iron content,the effect of heat treatment on the microstructure and the phase relationship have been studied.The phase relationship in the vicinity of the Laves phase is proposed     

Structure and Magnetostriction of (Dy_(0.7)Tb_(0.3))_(0.5)Pr_(0.5)Fe_x Alloys (1.10≤x≤1.85)

1. IntroductionInvestigation of rare earth-iron illtermetallic compounds is of great importance owing to their potential application as magnetostrictive transducerelemelltsll'ZI. It is possible to alloy the materials withthe same sign of magnetostriction but with the opposite sign of anisotropy in order to obtain the desiredratio of high magnetostriction to low magnetocrystalline anisotropy. The calculation of magnetostriction for rare earth-Fe Laves compounds indicates thatthe magnetostrict…     

Sm(Co_(0.74)Cu_(0.12)Fe_(0.1)Zr_(0.04))_(7.5)纳米晶烧结磁体的结构和磁性能

采用放电等离子烧结技术制备了致密纳米晶SmCoCuFeZr烧结磁体,研究了磁体的结构和磁性能.X衍射结果表明,烧结磁体具有TbCu_7结构.TEM观察显示,烧结磁体平均晶粒尺寸为35nm.室温时磁体的剩磁为0.49T,矫顽力高达1.42T,而剩磁比Mr/Ms为0.63,表明在纳米晶之间存在晶间交换耦合作用.     

热处理对(Fe_(0.52)Co_(0.30)Ni_(0.18))_(73)Cr_(17)Zr_(10)非晶合金的组织结构及磁性能的影响

采用单辊急冷法制备(Fe_(0.52)Co_(0.30)Ni_(0.18))_(73)Cr_(17)Zr_(10)非晶薄带,并对该合金进行等温退火。采用XRD,AFM,VSM研究退火温度对(Fe_(0.52)Co_(0.30)Ni_(0.18))_(73)Cr_(17)Zr_(10)非晶合金的组织结构和磁性能的影响。结果表明:非晶合金晶化过程为Am→α-Fe(Co)+Am′→α-Fe(Co)+Cr_2Ni_3+Fe_3Ni_2+Cr_2Zr+未知相。当退火温度Ti玻璃转变温度Tg时,由于结构弛豫、内应力的释放,合金的饱和磁化强度Ms有所提高;当晶化起始温度TxTi第一晶化峰值温度Tp1时,由于铁磁性α-Fe(Co)相的析出,Ms显著提升;当TiTp1时,由于晶粒长大和第二相的析出,Ms急剧恶化,565℃退火能够获得最好磁性能(Ms=106.8A·m~2·kg~(-1))。490℃和565℃退火后薄带表面的AFM观察表明,AFM图片所呈现的颗粒尺寸要比用Scherrer法测得的α-Fe(Co)纳米晶尺寸大得多,这是典型的包裹晶粒现象。     

浸渍LaNi_(0.6)Fe_(0.4)O_(3-δ)纳米颗粒对Zr_(0.84)Y_(0.16)O_(2-δ)-La_(0.8)Sr_(0.2)Cr_(0.5)Fe_(0.5)O_(3-δ)透氧膜性能的影响

采用流延–共压–共烧结法制备了具有多孔|致密|多孔Zr_(0.84)Y_(0.16)O_(2–δ)-La_(0.8)Sr_(0.2)Cr_(0.5)Fe_(0.5)O_(3–δ)(YSZ-LSCF)结构的透氧膜和多孔YSZ-LSCF|致密YSZ-LSCF|致密YSZ|致密YSZ-LSCF|多孔YSZ-LSCF结构的固体氧化物燃料电池。采用浸渍法在多孔层内壁上沉积了具有高催化活性的LaNi_(0.6)Fe_(0.4)O_(3–δ)(LNF)纳米颗粒,随着LNF浸渍量的提高,会在多孔层内壁上形成连续的导电网格,增加电化学反应活性位点,进而显著改善电极性能。当LNF浸渍量为12wt%时,电极性能达到最优,在800℃时阴极和阳极极化阻抗分别为0.26和0.08?·cm~2,在空气/CH_4梯度中氧渗透速率为7.6 mL/(cm~2·min),比未浸渍前提高了14倍。阻抗谱分析表明空气侧氧还原反应中的电荷转移反应是氧渗透过程的速率控制步骤。     

(1-x)(Mg_(0.7)Zn_(0.3))TiO_3-x(Ca_(0.61)Nd_(0.26))TiO_3系微波介质陶瓷介电性能研究(英文)

本实验研究了(1-x)(Mg_0.7Zn_0.3)TiO₃－x(Ca_0.61Nd_0.26)TiO₃体系陶瓷(MZCNT)的微波介电性能,通过(Ca_0.61Nd_0.26)TiO₃协调(Mg_0.7Zn_0.3)TiO₃陶瓷的谐振频率温度系数.实验发现,烧结温度和陶瓷组成对微波介电性能影响显著, 当烧结温度为1250℃时,可以获得良好的致密度,当烧结温度超过1300℃时,(Ca_0.61Nd_0.26)TiO₃ 的分解和Zn的蒸发导致陶瓷致密度和介电性能下降.此外,随着(Ca_0.61Nd_0.26)TiO₃含量的增大,材料的介电常数增大,品质因数减小.当 (Ca_0.61Nd_0.26)TiO₃含量为13%,烧结温度为1250℃,保温4h,（MZCNT）陶瓷具有优良微波介电性能,ε_r =24.3,Q·f=34000GHz,τ_f~-9×10^-6/℃,从而达到实用要求.     

Sm_(0.5)Ce_(0.5)(Co_(0.824)Mn_(0.059)Cu_(0.118))_(6.8)合金的相组成与磁性关系

用金相、X光、高功率衍射、电子探针及热磁分析等手段,对成分为Sm_(0.5)Ce_(0.5) (Co_(0.824)Cu_(0.118)Mn_(0.059))_(6.8)合金铸态、高温烧结及时效前后的磁体进行了相组成的研究。也对氢气,氩气下烧结的磁体进行了比较。试验结果表明:合金铸态存在着CaCu_5型(1:5相)和Th_2Zn_1,(Th_2Ni_(17))型(2:17相)。氩气保护下在1130℃淬火的试样主要是六角型2:17相(缺陷型)。它与低的内禀矫顽力相对应。也存在少量的Sm_2O_3。经750℃,600℃多阶时效淬火的试样,发现在六角型2:17基相中,伴随着调幅结构的出现,析出了少量的菱形2:17相。它与高的内禀矫顽力相对应。氢气保护下,于1130℃淬火的试样,发现其内禀矫顽力也相当高。此时也观察到第二相的析出。第二相以最佳尺寸析出,造成了畴壁钉扎点,从而对内禀矫顽力有较大的贡献。     

烧结温度对(Nd_(0.947)Dy_(0.053))_(15)(Fe_(0.83)Co_(0.17))77B_8永磁体剩磁的影响

本文用磁测量和差热分析等技术,研究了(Nd_(0.947)Dy_(0.053))_(15)(Fe_(0.83)Co_(0.17))_(77)B_8合金的剩磁(Br)和最大磁能积(BH)_(max)与烧结温度(T)的关系。合金的Br主要取决于烧结温度,而时效处理对Br的影响甚小。(BH)_(max)与Br~2成正比关系。对于所研究的磁体,最佳烧结温度为1100℃,最佳剩磁Br=1.250T,(BH)_(max)=286.1KJ/m~3。