掺杂Y2O3对BaZr0.1Ti0.9O3陶瓷电介质性能的影响

研究了掺杂量不同的Y2O3对BaZr0.1R.9O3微观形貌及介电性能的影响.实验发现:通过XRD物相分析,所有试样均形成典型的钙钛矿结构的主晶相,说明钇掺杂并未改变锆钛酸钡的晶型结构.一定量的Y2O3可抑制晶粒的长大,使晶粒细化,降低气孔率,试样得到致密化.当Y2O3的掺入量为0.05mol％时,试样的介电损耗最小.Y2O3掺杂可提高锫钛酸钡陶瓷居里点处的介电常数,展宽介电温谱,提高材料的实际应用性.     

Y2O3掺杂对ZnO压敏陶浇电性能的影响

采用传统的陶瓷工艺，对比研究了不同Y2O3含量对ZnO压敏电阻器的性能的影响。结果表明：掺杂Y2O3能够细化晶粒、提高ZnO压敏电阻器的电压梯度．当掺杂量为0．8％时，电位梯度达270V／mm。但样品致密度较低。电性能下降。当Y2O3含量为0．1％时，电位梯度与未掺杂Y2O3的样品相当，其致密度较高，晶粒尺寸一致，电性能最佳。     

Y2O3掺杂对Mg0.8Mn0.2Fe2O4结构及红外性能的影响

采用常规固相合成法制备Y2O3掺杂的尖晶石型Mg0.8Mn0.2Fe2O4(MMF)红外辐射材料,借助于X射线衍射、红外光谱、扫描电子显微镜和红外发射率测试,研究了y3+掺杂对材料的微观结构及红外辐射性能的影响.当Y2O3掺杂量为0.6％(质量分数)时,镁锰铁氧体性能最优,在3～5 μm和8～12 μm波段的红外发射率分别达到0.869和0.948.     

Y2O3掺杂对17Ni/(NiFe2O4-10NiO)金属陶瓷高温氧化性能的影响

氩气气氛保护下采用气压烧结技术制备掺杂Y2O3的17Ni/(NiFe2O4-10NiO)金属陶瓷惰性阳极,在电解温度(960℃)下,对材料进行抗高温氧化性能研究.采用SEM分析材料及氧化产物的各物相分布情况、氧化形貌,并利用XRD进行成分分析.结果表明,金属陶瓷阳极的氧化动力曲线均大致符合抛物线规律;掺杂适量的Y2 O3对金属相的分散有一定作用,并能有效抑制烧结试样及氧化物的孔洞生成,从而显著改善该金属陶瓷的抗高温氧化性能,其中,当Y2 O3掺杂量为0.5％时,材料抗高温氧化性能最好,30 h后单位面积氧化增重量仅为10.6591 mg/cm2.     

Y_2O_3掺杂对ZnO压敏陶瓷电性能的影响

采用传统的陶瓷工艺,对比研究了不同Y2O3含量对ZnO压敏电阻器的性能的影响。结果表明:掺杂Y2O3能够细化晶粒、提高ZnO压敏电阻器的电压梯度,当掺杂量为0.8%时,电位梯度达270V/mm,但样品致密度较低,电性能下降。当Y2O3含量为0.1%时,电位梯度与未掺杂Y2O3的样品相当,其致密度较高,晶粒尺寸一致,电性能最佳。     

锰掺杂对PNW-PMS-PZT压电陶瓷结构和性能的影响

采用传统陶瓷工艺制备了Pb(Ni1/2W1/2)O3-Pb(Mn1/3Sb2/3)O3-Pb(Ti，Zr)O3-xMnO2压电陶瓷，分析了经1150℃烧结2h制备的陶瓷样品的相结构组成。实验结果表明：所有陶瓷样品均为钙钛矿相，未发现其它晶相。随着锰掺杂量的增加，陶瓷晶粒逐渐长大。研究了不同剂量的锰掺杂对压电陶瓷介电和压电性能的影响。结果表明：随着锰掺杂量的增加，材料逐渐变“硬”，当MnO2掺杂量少于0．2％(按质量计，下同)时，相对介电常数εr、压电常数d33和机械品质因数Qm逐渐增加，介电损耗tanδ减小；当MnO2掺杂量多于0．2％时，εr、d33和Qm逐渐降低，tanδ增加。随着锰掺杂量的增加，机电耦合系数kp和Curie温度θc逐渐减小。MnO2掺杂量为0．2％的压电陶瓷适合制作大功率压电陶瓷变压器。其压电性能为：εr=2138，tanδ=0．0058，kp=0．613，Qm=1275，d33=380pC／N和θc=205℃。     

Y_2O_3掺杂对Mg_(0.8)Mn_(0.2)Fe_2O_4结构及红外性能的影响（英文）

采用常规固相合成法制备Y2O3掺杂的尖晶石型Mg0.8Mn0.2Fe2O4(MMF)红外辐射材料,借助于X射线衍射、红外光谱、扫描电子显微镜和红外发射率测试,研究了Y3+掺杂对材料的微观结构及红外辐射性能的影响。当Y2O3掺杂量为0.6%(质量分数)时,镁锰铁氧体性能最优,在3~5μm和8~12μm波段的红外发射率分别达到0.869和0.948。     

烧结助剂对多孔氮化硅陶瓷的力学性能及介电性能的影响

通过添加烧结助剂,采用常压烧结工艺制备出不同气孔率(19%～54%)的氮化硅陶瓷.采用Archimedes法、三点弯曲法和Vickers硬度测试法测量了材料的密度、气孔率、抗弯强度及硬度.用X射线衍射及扫描电镜检测了相组成和显微结构.用谐振腔法测试了氮化硅陶瓷在10.2 GHz的介电特性.结果表明:材料具有优良的介电性能.随着烧结助剂的减少,样品中气孔率增加,力学性能有所下降,介电常数和介电损耗降低.添加Lu2O3所制备的氮化硅陶瓷的力学性能和介电性能优于添加Eu2O3或Y2O3制备的氮化硅陶瓷.当气孔率高于50%时,多孔氮化硅陶瓷(添加入5%的Y2O3或Lu2O3,或Eu2O3,质量分数)的抗弯强度可达170 MPa,介电常数为3.0～3.2,介电损耗为0.000 6～0.002.     

Y2O3掺杂对(Bi0.5Na0.5)0.94Ba0.06TiO3无铅压电陶瓷性能的影响研究

采用传统固相反应法制备了Y2O3掺杂(Bi0.5Na0.5)0.94Ba0.06TiO3(简写为BNBT6)陶瓷[简称为BNBT6-x(wt%)Y2O3陶瓷].研究了Y2O3 (0.2wt%～0.8wt%)掺杂对BNBT6陶瓷的结构、介电、压电、铁电性能的影响.结果表明,所有Y2O3掺杂陶瓷样品均形成了单一的钙钛矿结构;陶瓷的介电、压电、铁电性能受Y2O3掺杂的影响较为显著:当掺杂0.4wt%Y2O3时,10 kHz频率下测得的室温εr达到1530,且tanδ较小,为0.050,d33达到152 pC/N,kp=0.27,Qm=134.掺杂0.2wt%的Y2O3时BNBT6陶瓷的d33为145 pC/N,kp增大到0.29,Qm达到173,tanδ为0.053;掺杂适量Y2O3的BNBT6陶瓷铁电性能也得到改善.     

Y3+替代Bi3+对Bi2(Zn1/3Nb2/3)2O7陶瓷显微结构和介电性能的影响

本文研究了Y3 替代Bi3 对Bi2O3-ZnO-Nb2O5系介质材料结构和性能的影响,并借助X射线、扫描电镜、LCR4284测试仪对其相结构和介电性能进行分析。研究结果表明,随着Y3 替代量的增加,Bi2O3-ZnO-Nb2O5系介质材料的晶粒尺寸、介电常数、介电损耗都有所变化,当替代量x=0.2时,介电性最佳,介电常数为79.4094,介电损耗为0.002125。     

High and temperature-stable dielectric constants in PNb9O25 ceramic

PNb₉O₂₅ ceramic was prepared using a sparking plasma sintering (SPS) method. Microstructure, dielectric and electrical properties of the ceramic were investigated. Dense ceramic was obtained, and the ceramic exhibited a high dielectric constant (>1000) and a low dielectric loss (∼2%) in the investigated frequency range of 100 Hz-100 kHz at room temperature. Dielectric relaxations with strong frequency dispersion occurred at temperatures higher than 250°C, which were due to oxygen vacancies. A highly stable capacitance (< 10% deviation) over a wide temperature range of –30°C to –200°C was obtained. The ceramic also showed a relatively high electrical conductivity (>4 × 10⁻⁸ S/cm) with an activation energy of approximately 0.9 eV in the temperature range of >200°C.     

微波介质陶瓷的研究现状及展望

微波介质陶瓷是现代通讯技术中的关键基础材料,它的应用日益受到人们的重视。本文综述了四类微波介质陶瓷的研究现状,并对其未来的发展进行了展望。     

塑料高频焊接技术

高频焊是一种依靠极性塑料的介质滞后损耗产生内部发热的焊接方法。由于具有焊接速度快、焊缝强度高和外观质量优良等优点,该方法在医疗、包装、汽车行业得到了广泛的应用。本文论及塑料高频焊接技术。主要介绍了高频焊的原理、焊接过程、焊接设备、工艺参数、接头形式、焊接性、特点、应用和最新进展。     

Room‐temperature‐densified Li2MoO4 ceramic patch antenna and the effect of humidity

A patch antenna was realized utilizing a Li₂MoO₄ disk fabricated by a room‐temperature densification method, where the densification takes place during pressing. Therefore, the size of the ceramic can easily be managed by controlling the mold dimensions, making this method advantageous for patch antenna design. The antenna showed reasonably good performance. A relative humidity of 80% lowered the resonant frequency and reduced the efficiency of the antenna. Use of a conformal coating reduced the changes and speeded up their reversibility. The results show that the room‐temperature densified Li₂MoO₄ ceramics are feasible for use under high humidity with a silicone coating.     

The dielectric properties for (Nb,In,B) co-doped rutile TiO2 ceramics

Recently, colossal permittivities (~10⁵) and low loss factors (<0.1) were reported in (Nb+In) co-doped rutile TiO₂ ceramics, which have attracted considerable attention. In this work, (Nb,In,B) co-doped rutile TiO₂ ceramics were investigated for achieving temperature- and frequency- stable dielectric properties in TiO₂ based colossal dielectric ceramics. The (Nb,In,B) co-doped rutile TiO₂ ceramics were prepared by conventional solid-state reaction method. The microstructures, dielectric properties and complex impedance of 1 mol.% (Nb+In) co-doped rutile TiO₂ (TINO) and xwt% B₂O₃ (x=0.5, 1, 2 and 4) doped TINO were systematically investigated and compared. It was found that by doping B₂O₃ the sintering temperature of TINO ceramics can be reduced by 100 °C. Meanwhile, the dielectric loss of TINO ceramics was decreased by doping B₂O₃. In the ₂wt% B₂O₃ doped TINO ceramics, the dielectric permittivity kept a high value of >2.0×10⁵ and the dielectric loss was lower than 0.1 in a frequency range of 10²−10⁵ Hz and a temperature range of 25–200 °C.     

顺丁橡胶/有机蒙脱土纳米复合材料的介电性能研究

采用机械混炼法制备了顺丁橡胶/有机蒙脱土(BR/OMMT)纳米复合材料;采用精密电桥对纳米复合材料的介电性能进行了研究。结果表明,纳米复合材料的相对介电系数(ε)随温度的升高逐渐增加,而介电损耗(tanδ)随温度的升高分别出现β峰和α峰。当晶区完全融化后,ε及tanδ随温度的升高而急剧上升;在频率一定时,纳米复合材料的介电损耗随OMMT含量的增加逐渐增加,并且峰值向高温方向移动;在OMMT含量一定时,在相同温度下,复合材料的ε和tanδ均随着频率的升高而下降;随着频率的升高,介电损耗峰向高温方向移动。     

Microwave dielectric properties of low temperature fired Ba5Nb4O15 ‐ BaWO4 ceramics supplemented with their own nanoparticles for LTCC applications

Polycrystalline Ba₅Nb₄O₁₅ (BNO) ‐ BaWO₄ (BWO) composite ceramics are prepared by adding their own nanoparticles as a sintering aid. The prepared samples exhibited the maximum relative density of 98.2% at 900°C. The complex dielectric response of these composite ceramics are analysed by Havriliak ‐ Negami (HN) equation. The BNO ‐ BWO composite added with x=3 wt% of their nanoparticles, fired at 900oC displayed the best microwave dielectric properties; εr=39 and Q×f0=59.8 THz at 9.44 GHz. The obtained results of BNO ‐ BWO composite makes this material as a potential candidate for LTCC applications.     

Decisive role of mixed‐valence structure in colossal dielectric constant of LaFeO3

The role of mixed‐valence structure in colossal dielectric constant (CDC) behavior has been investigated in LaFeO₃ ceramics by tuning the ratio of Fe²⁺/Fe³⁺ through substituting Al for Fe. The ratio of Fe²⁺/Fe³⁺ is decreased gradually from 1.0 to 0.0 by increasing the concentration of Al³⁺. Two clear‐cut correlations have been found: (i) the relationship between the CDC behavior and the ratio of Fe²⁺/Fe³⁺ follows an exponential function and (ii) the activation energy of the polaron relaxation is proportional to , where is the intrinsic dielectric constant. These findings underscore the role of the mixed‐valence structure in CDC behavior and suggest that adjusting the mixed‐valence structure through doping/alloying can be a promising strategy to achieve superior CDC behavior in transition‐metal oxides.     

几种典型的低介硅酸盐微波陶瓷材料的研究现状

概述了MgO-SiO2,Zn2SiO4,CaSiO3和Re2O3-SiO2(Re=稀土元素)等低介电常数硅酸盐微波陶瓷材料体系的研究进展.讨论了微波介质陶瓷的结构、微波介电性能、降温方法、机理及其存在的问题,指出了微波陶瓷材料今后的研究方向.     

透波复合材料研究进展

介绍透波材料的选用原则及其介电特性,探讨了树脂基、无机非金属基通用透波复合材料和人工介质材料、耐高温有机材料等特种透波复合材料的研究进展,简介湿度、树脂含量、孔隙率、吸水性、后处理温度及时间、纤维表面处理等因素对复合材料常温透波性能的影响及结构／微结构、成分／微成分、物态相变等材料的本征因素对复合材料高温透波性能的影响。