La_2O_3和Sm_2O_3掺杂对SrTiO_3陶瓷结构与性能的影响

对SrTiO3陶瓷分别进行了La2O3和Sm2O3微量掺杂改性研究,观察了稀土掺杂后陶瓷样品的显微结构,研究了其介电损耗、相对介电常数及电容量变化率随测试温度变化的规律,分析了样品在不同测试电压下的绝缘特性。研究结果表明,La2O3和Sm2O3的微量掺杂对SrTiO3陶瓷的影响相似。稀土掺杂后,样品的晶粒尺寸变小,介电损耗增大,相对介电常数明显提高,电容量变化率明显改善,绝缘电阻明显减小。当稀土掺杂量高于0.2%(摩尔分数)时,La2O3的细晶效果比Sm2O3更明显。     

Nd_2O_3和Sm_2O_3掺杂钛酸锌介电陶瓷的结构与性能

为了改善ZnTiO3介电陶瓷的性能,研究了Nd2O3和Sm2O3掺杂对ZnTiO3陶瓷结构与介电性能的影响,借助TEM型同轴谐振器测量陶瓷的微波介电性能。研究表明,掺杂Sm2O3形成新相Sm2Ti2O7,少量Sm2O3掺杂能有效抑制ZnTiO3分解;掺杂Nd2O3形成新相Nd2Ti2O7和Nd4Ti9O24;Nd2O3和Sm2O3掺杂均能提高谐振器的无载Q值,且Nd2O3的掺杂效果优于Sm2O3:Nd2O3掺杂能使陶瓷的τf从正值向负值变化,通过调整Nd2O3掺杂量(质量分数5%～10%),可获得τf近零、无载Q值大于260的陶瓷组成,可用于制备分米波段的滤波器。     

β-BZT陶瓷中添加MoO3及气氛烧结

研究了添加低熔点氧化物MoO3及N2/空气/O2气氛烧结对微波介质陶瓷Bi2(Zn1/3Nb2/3)2O7(β-BZT)的结构和介电性能的影响.结果表明,烧结温度可降低100 ℃;样品的介电常数和品质因数随添加量增多而下降;掺杂MoO3的质量分数小于1%,样品均致密、显微形貌较好;MoO3添加量为0.05%时样品的介电常数约65,电容温度系数仅76×10-6/℃,品质因数值可达943;氧分压对样品的显微形貌和介电性能也有影响.     

掺杂Sm2O3对BZT20介质瓷性能的影响

以碳酸钡、二氧化锆和二氧化钛等为原料,Sm2O3为掺杂剂,制得了Ba(Zr0.2Ti0.8)O3系介质瓷,并研究了其性能,用扫描电镜对试样微观形貌进行了观察.结果表明,当x(Sm2O3)＜0.2%时,Sm3+进入晶格A位后,随掺杂量的增加,Sm3+倾向于进入晶格B位.Sm2O3的掺杂量对试样介电常数和损耗有显著影响,x(Sm2O3)=0.2%时,试样介电常数最高(约为5 600);随Sm2O3掺杂量继续增加,试样介电损耗得到明显改善,最低降至0.002 1.     

稀土离子掺杂对钨酸盐荧光粉发光性能的研究(英文)

红色荧光粉的在制备荧光转换型白光LED时是不可或缺的,因为红色荧光粉在制备高显色指数白光LED中发挥着重要的作用。LiEuW2O8是最近几年最新发展起来的一种很有潜力的红色荧光粉。主要研究了稀土离子掺杂对LiEuW2O8发光性能的影响。采用高温固相法制备钨酸锂铕系列红色荧光粉。La3+和Sm3+取代LiEuW2O8中的Eu3+,La3+和Sm3+通过再吸收的方式将能量传递给Eu3+,实现对Eu3+的敏化作用。La3+和Sm3+的掺杂并没有改变样品的激发和发射峰,也没有改变晶体结构,但是掺入后能显著提高样品的发射强度。La3+的最佳掺杂量(物质的量分数)为3%,Sm3+的最佳掺杂量为4%。     

不同含锰化合物掺杂对BST-MgO陶瓷介电性能的影响

采用普通固相反应法制备了0.45Ba0.55Sr0.45TiO3-0.55MgO-Mn(NO3)2/MnCO3(简称BST-MgO)陶瓷,通过XRD和SEM研究了不同形态含锰化合物(固态MnCO3及液态Mn(NO3)2)掺杂对所制BST-MgO陶瓷致密化及微波介电性能的影响。结果表明,液态Mn(NO3)2掺杂可以增加锰离子进入BST晶格的几率,同时抑制镁离子进入BST晶格,提高BST-MgO陶瓷的致密度,降低介质损耗,获得较高的综合性能:10 kHz下r=116,tan=0.003 8,可调率(Tu)为19.64%,优值K=51.68;3 GHz时Q.f值达788 GHz。     

宽带激光熔覆梯度稀土生物陶瓷涂层的生物活性

为了减少激光熔覆过程中基材与生物陶瓷涂层之间的热裂纹, 提高涂层与基材的结合强度, 设计了一种梯度稀土生物陶瓷涂层, 采用宽带激光熔覆技术,在TC4钛合金表面制备了含HA＋β－TCP活性相的稀土活性梯度生物陶瓷复合涂层。利用SEM 、XRD分析手段对涂层形貌、相组成进行了研究; 通过模拟体液(SBF)浸泡实验(浸泡7 、14 d)考察了生物陶瓷涂层的生物活性; 利用电化学分析仪测试了生物活性陶瓷涂层的耐腐蚀性。结果表明, 当稀土氧化物Nd2O3添加量为w(Nd2O3)＝0.6%时, 宽带激光熔覆过程中催化合成HA＋β－TCP活性相的数量最多, 具有优异的表面形貌; 当稀土氧化物Nd2O3添加量为w(Nd2O3)＝0.6%时, 梯度稀土生物陶瓷涂层在SBF中浸泡不同时间点后表面沉积的类骨磷灰石相数量均较未加入Nd2O3的梯度生物陶瓷涂层多, 具有最好的生物活性, 且耐腐蚀性最佳。     

掺杂纳米Nd2O3聚合物分散液晶的紫外电光特性

通过实验测试,研究掺杂稀土氧化物Nd2O3纳米粒子的聚合物分散液晶(PDLC)在波长为320～400 nm内的电光特性.结果表明,Nd2O3的掺杂可有效地实现PDLC在紫外的电光开关特性.这种掺杂使PDLC在紫外的透过率为零的区域由原来的320～325 nm扩展为320～340 nm左右,同时在波长365nm附近出现了...     

Sm2O3掺杂对BZN基陶瓷介电性能的影响

研究了Sm2O3掺杂的Bi2O3-ZnO-Nb2O5(BZN)基陶瓷(Bi1.5–SmxZn0.5)(Zn0.5Nb1.5)O7(0≤x≤1.5,BSZN)的结构x和介电性能。实验采用传统的固相反应法制备陶瓷样品,XRD分析样品的相结构。结果表明:未掺杂的BZN陶瓷其结构为立方焦绿石单相;当Sm2O3掺杂量较少(0相似文献   

稀土掺杂的BSTO/MgO铁电移相材料

为了提高移相器性能,通过掺杂的方法研究了La2O3、Sm2O3、Dy2O3、CeO2等稀土氧化物对BSTO/MgO铁电移相材料低频(10kHz)与高频(2.5GHz左右)相对介电常数εr、介质损耗tgδ和调谐性T等的影响,并对影响机理作了初步探讨。结果表明,掺杂摩尔分数为0.5%La2O3的BSTO/MgO系统基本上达到了相控阵移相器在高频下工作的要求10kHz下,tgδ=4×10–4,T=14.6%;2.41GHz下,tgδ=6.7×10–3。     

Preparation and electrical properties of SrTiO3 ceramics doped with M2O3–PbO–CuO

SrTiO₃ dielectric ceramics were fabricated in air by using M₂O₃–CuO–PbO as dopants (M=Sm,Nd,La,Yb). The obtained ceramics exhibited a high dielectric constant (₂₅>4880) with stable temperature characteristics. With doping the rare-earth ions from Sm → Nd → La → Yb, the corresponding dielectric constant regularly decreased. The investigation of microstructure showed that Yb additives benefited to the grain growth and CuO additives mainly segregated at the grain boundaries to form the insulation layers. According to the results, the conduction mechanism of SrTiO₃–M₂O₃–CuO–PbO system was discussed.     

Thermoelectric Properties of the Ca<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>R<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>MnO<Subscript>3</Subscript> Perovskite System (R: Pr,Nd, Sm) for High-Temperature Applications

Perovskite oxides have attracted considerable attention in the area of thermoelectrics owing to the advantages of their isotropic crystal structure and straightforward control of their electrical properties. Among the many perovskites, different types of polycrystalline Ca_1−x R _x MnO₃ (R: Pr, Nd, Sm) were prepared by solid-state reaction in this study. Three different rare-earth dopants were substituted at the Ca-ion site at various amounts. Considering phase stability, rare-earth ions with nearly the same ionic radius as Ca²⁺ were selected. To assess thermoelectric performance, the electrical conductivity, Seebeck coefficient, and power factor were measured, and phase analysis was conducted. The effects of ionic radius variation on single phase formation and the effect of doping amount on carrier concentration are discussed.     

亚微米BaTiO_3 X7R MLC细晶陶瓷介质材料的介电性能研究

基于晶体化学、材料物理化学、电介质物理等基础理论,运用XRD、TEM、EDX、SEM等现代微观分析手段,对亚微米钛酸钡超细粉料制备技术以及高介高性能X7R MLC瓷料和高压高性能X7R MLC瓷料的介电性能进行了研究。     

Additional Y3+ or Al3+ Dopants on the Ferromagnetism of Co Doped Ceria Diluted Magnetic Oxide

Al2O3 and Y2O3 have been respectively chosen for additional dopants to investigate the influence on the ferromagnetism of Co doped CeO2 bulk. Results indicate that ferromagnetism (FM) of Co doped CeO2 decrease with additional Al3+. Accordingly, certain amount of Y3+ can readily be incorporated into the lattice of CeO2 with the decrease of its grain size as well as some pores formation, leading to an enhancement of FM with a positive correlation between magnetization and Y3+ doping content. This experimental result is helpful both in understanding FM origination in diluted magnetic oxide (DMO) as well as to improve the moments of DMO applicable in spintronic devices.     

Additional Y3+ or Al3+ Dopants on the Ferromagnetism of Co Doped Ceria Diluted Magnetic Oxide

Al2O3 and Y2O3 have been respectively chosen for additional dopants to investigate the influence on the ferromagnetism of Co doped CeO2 bulk. Results indicate that ferromagnetism (FM) of Co doped CeO2 decrease with additional Al3+. Accordingly, certain amount of Y3+ can readily be incorporated into the lattice of CeO2 with the decrease of its grain size as well as some pores formation, leading to an enhancement of FM with a positive correlation between magnetization and Y3+ doping content. This experimental result is helpful both in understanding FM origination in diluted magnetic oxide (DMO) as well as to improve the moments of DMO applicable in spintronic devices.     

Nd2O3掺杂BaZr0.2Ti0.8O3陶瓷的介电性能

在溶胶-凝胶法制备钛酸钡(BaZr0.2Ti0.8O3)超细粉体的过程中,使用液相掺杂的方式在溶胶过程中进行了稀土元素Nd的掺杂。掺杂摩尔分数为0、0.001、0.002、0.003、0.004和0.005。掺杂改性后的BaZr0.2Ti0.8O3粉体,通过X-射线衍射(XRD)测试,结果表明在摩尔分数为0.005以内的稀土Nd掺杂并未改变BaZr0.2Ti0.8O3的钙钛矿结构。粉体烧结的陶瓷介电性能得到较大的改善:介电常数由3 389提高到4 493,而介电损耗在60 Hz时由1.4%降低到0.35%。     

BCL助烧剂对CSLST微波介质陶瓷性能的影响

采用B2O3-CuO-Li2CO3(BCL)作为助烧剂对(Ca0.9375Sr0.0625)0.3(Li0.5Sm0.5)0.7TiO3(CSLST)微波介质陶瓷进行降温烧结。系统讨论了BCL的添加量对CSLST微波介质陶瓷的烧结行为、晶体结构及微波介电性能的影响。结果表明:BCL的加入将CSLST陶瓷的烧结温度从1 250℃降至925℃。当BCL添加量小于质量分数5.5%时,样品中只含单一的钙钛矿结构晶体,而当BCL添加量大于质量分数7.5%时,则会产生第二相。添加BCL的质量分数为5.5%,烧结温度为925℃保温5 h,所制CSLST陶瓷具有良好的微波介电性能:εr=86.69,Q.f=2 267 GHz,τf=29.3×10–6/℃。     

H_3BO_3掺杂Li_2ZnTi_3O_8陶瓷的微波介电性能

采用传统的固相烧结工艺制备了H3BO3掺杂的Li2ZnTi3O8陶瓷。研究了H3BO3掺杂量对所制Li2ZnTi3O8陶瓷的烧结特性、相成分、微观结构以及微波介电性能的影响。结果表明:H3BO3对于所制陶瓷相成分没有影响,仅为单一的Li2ZnTi3O8相;H3BO3能够将Li2ZnTi3O8陶瓷的烧结温度降低200℃左右,同时没有显著损害该陶瓷的微波介电性能;当H3BO3掺杂量为质量分数2.0%时,950℃烧结的Li2ZnTi3O8陶瓷微波具有良好的介电性能:εr=25.99,Q.f=54 926GHz,τf=-12.17×10–6/℃。