钛酸钡基电子陶瓷材料的改性进展

钛酸钡基电子陶瓷材料广泛应用于电容器、集成电路、传感器及热敏电阻等领域。高容量、小型化、抗击穿及低损耗等工业需求对钛酸钡基电子陶瓷材料的性能提出更高的要求,改性则是提高陶瓷材料性能的主要手段。综述了近年来钛酸钡基电子陶瓷材料在掺杂改性、复合改性及物理改性方面的研究进展。分析了钛酸钡基电子陶瓷材料在改性中存在的问题,比如：常规元素掺杂制备参数优化不足、稀土元素掺杂种类偏少、包覆效果待提升、聚合物陶瓷复合体综合性能欠佳、烧结工艺尚待优化等。提出了解决方法,比如：探索多种元素掺杂、优化工艺参数、改进包覆与聚合方式等。指出了钛酸钡基电子陶瓷材料的未来发展方向,即：强化烧结过程中晶粒尺寸、晶体形状、组分调控的机理研究,选取更多稀土元素进行改性,探索包覆掺杂改性、聚合物复合改性等新工艺。     

《中国陶瓷》2002年总目录

研究与开发 电子陶瓷材料最佳掺杂含量的理论研究 范志新等(01.01) 直接凝胶凝固成型SiC(M,Y)一A1203复合陶瓷材料 (Ⅱ)基本原理及工艺过程研究 张存满等(01.04) 陶瓷品数字建模方法新探 熊汉伟等(01.07) 纳米远红外陶瓷粉体的制备工艺与性能研究 刘维良等(01.10’) 新型电热膜     

掺杂离子及掺杂工艺对钛酸钡性能的影响

钛酸钡基陶瓷是一种新兴的多功能电子陶瓷材料，由于其优异的电学性能而在很多领域有着广泛的应用，掺杂离子以及掺杂工艺对钛酸钡的性能有显著的影响。对常用的几种掺杂离子，如钙、镁、铅、锶、锆、锡和稀土元素，以及各种掺杂工艺对钛酸钡性能的影响进行了简单评述，并预测了未来的研究方向。     

电子陶瓷成形用有机材料

介绍了电子陶瓷成形方法，并以薄片成形方法为例分析了所用有机材料的作用，认为在此生产中应根据制品形状、特性等从各种成形方法和有机材料中选择最佳组合。     

掺杂改性对钛酸钡基陶瓷储能密度的影响

钛酸钡基陶瓷具备优良的电性能,是现代功能技术陶瓷应用最广泛的一类材料,是电子陶瓷元器件的主要原材料之一。本文综述了材料储能密度及影响因素、掺杂改性对钛酸钡基陶瓷介电性能的影响、钛酸钡基陶瓷材料的应用,并对钛酸钡基陶瓷材料Nb、Gd掺杂改性的研究进行了展望。     

工业电子陶瓷材料的分类、应用及发展趋势

本文针对工业用电子陶瓷材料的性能特点,研究了工业用电子陶瓷材料的应用领域,分析了工业用电子陶瓷材料的分类,并介绍了电子陶瓷产业加速研发新材料态势。同时,指出了工业用电子陶瓷技术的发展趋势。     

锰掺杂对压电陶瓷介电性能的影响

采用传统的电子陶瓷工艺制备了高性能四元系压电陶瓷（PZN-PMS-PZT）。考察了不同剂量锰掺杂对压电陶瓷的室温介电常数（εTr)，介电常数温度谱以及居里温度（Tc)的影响。实验结果表明：随着Mn含量的增加，压电陶瓷的室温介电常数εTr减小；由于内偏置场的影响，居里温度Tc随锰含量的增加而增加。     

令人关注的工业电子陶瓷材料及其应用

电子陶瓷是指在电子工业中能够利用电、磁性质,通过对表面、晶界和尺寸结构的精密控制而最终获得具有新功能的陶瓷。由于陶瓷材料具有高强度、高硬度、耐腐蚀、耐高温等特征,使之成为新材料的发展重点,受到广泛关注。针对工业用电子陶瓷材料的性能特点,研究了工业用电子陶瓷材料的应用领域,分析了工业用电子陶瓷材料的分类,介绍了电子陶瓷产业加速研发新材料态势,同时指出了工业用电子陶瓷技术的发展趋势。     

电子陶瓷技术及其产业走向未来

电子陶瓷在电子工业中能够利用电、磁性质,是通过对表面、晶界和尺寸结构的精密控制而最终获得具有新功能的陶瓷。由于陶瓷材料具有高强度、高硬度、耐腐蚀、耐高温等特征,使之成为新材料的发展中心,受到广泛关注。针对工业用电子陶瓷材料的性能特点,研究了工业用电子陶瓷材料的应用领域,分析了工业用电子陶瓷材料的分类,介绍了电子陶瓷产业加速研发新材料态势,同时指出了工业用电子陶瓷技术的发展趋势。     

电子陶瓷的广泛应用

电子陶瓷不仅具有传统陶瓷的耐高温、耐腐蚀、耐风化等特性，而且在电、磁、声、光等方面具有许多优异的性能。19世纪末到20世纪初是电子陶瓷的萌芽时期，到现在为止，材料科学工作者已开发出了许多性能远远优于天然矿物的电子材料，例如：磁性材料铁氧体，铁电材料钛酸钡等。电子陶瓷的特殊性能主要取决于材料内部的电子状态、原子核结构以及原子的组合、     

用K值法对硫铝酸钙含量进行定量分析研究

以电石渣、脱硫石膏、粉煤灰等工业废渣为原料,并添加氟化钙、二氧化钛、氧化铜等不同种类和掺量的矿化剂,制备以硅酸二钙和硫铝酸钙为主要矿物的多孔胶凝材料;运用X射线衍射技术,通过K值法对硫铝酸钙含量进行定量分析,探讨不同矿化剂的掺入对硫铝酸钙矿物形成的影响。实验结果表明：矿化剂的加入能够降低硫铝酸钙的形成温度,同时能促进硫铝酸钙的形成。氟化钙掺量为1%（质量分数）时硫铝酸钙的含量最高,为12.43%（质量分数）;当氟化钙掺量超过1%时硫铝酸钙含量下降。二氧化钛掺量为0.5%（质量分数）时硫铝酸钙含量最高,达17.85%（质量分数）;当二氧化钛掺量超过1.5%时硫铝酸钙含量下降较为明显。氧化铜适宜的掺量为0.5%~1.0%（质量分数）,掺量超过1.5%时硫铝酸钙含量显著下降。     

Designed nitrogen doping of few-layer graphene functionalized by selective oxygenic groups

Few-layer nitrogen doped graphene was synthesized originating from graphene oxide functionalized by selective oxygenic functional groups (hydroxyl, carbonyl, carboxyl etc.) under hydrothermal conditions, respectively. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) observation evidenced few-layer feature of the graphene oxide. X-ray diffraction (XRD) pattern confirmed phase structure of the graphene oxide and reduced graphene oxide. Nitrogen doping content and bonding configuration of the graphene was determined by X-ray photoelectron spectroscopy (XPS), which indicated that different oxygenic functional groups were evidently different in affecting the nitrogen doping process. Compared with other oxygenic groups, carboxyl group played a crucial role in the initial stage of nitrogen doping while hydroxyls exhibited more evident contribution to the doping process in the late stage of the reaction. Formation of graphitic-like nitrogen species was controlled by a synergistic effect of the involved oxygenic groups (e.g., -COOH, -OH, C-O-C, etc.). The doping mechanism of nitrogen in the graphene was scrutinized. The research in this work may not only contribute to the fundamental understandings of nitrogen doping within graphene but promote the development of producing novel graphene-based devices with designed surface functionalization.     

银、氟双元素改性TiO2光催化材料的性能

以多孔泡沫镍为载体,采用水热合成法制备了Ag修饰和Ag-F共改性多孔TiO2光催化材料,用多种方法对其进行了表征,并评价了其对水中罗丹明B的降解性能. 罗丹明B的光催化降解反应符合零级动力学规律,TiO2中主要成分为锐钛矿型纳米TiO2晶体,经500℃煅烧0.5 h后光催化性能提高. Ag修饰TiO2的光催化性能随Ag修饰量的增加先升高后下降,Ag修饰量大于0.6%时,其光催化性能又提高,最佳Ag修饰量为1.2%. 煅烧处理使样品的光催化性能提高,当Ag修饰量为0.8%时,其光催化性能最优. 1.2% Ag和2.0% F共改性的多孔光催化材料的光催化性能远优于单一Ag修饰材料.     

Microstructure and thermal shock resistance of Nd2O3-doped YSZ-based thermal barrier coatings

To study the impact of rare earth oxide doping on the thermal failure of thermal barrier coatings, 0.5 mol%, 1.0 mol% and 1.5 mol% Nd₂O₃-doped YSZ coatings were prepared by explosive spraying. SEM, XRD, EDS and microhardness testing were used to analyse the effect of different rare earth oxide doping contents on the morphology, composition and mechanical properties of the coatings. With an increase in the Nd₂O₃ doping content, the porosity of the coatings was reduced. The decrease in the porosity increased the compactness of the coatings and improved the microhardness and fracture toughness. The bonding strength and thermal shock resistance of the coatings were the highest among the samples herein when the rare earth doping content was 1.0 mol%, and the values were 37.6 MPa and 200 times, respectively. The thermal shock failure mode of the coating was mainly due to the exfoliation of the inner layer of the ceramic layer. The luminous intensity of the coating increased with increasing rare earth oxide doping content, and the emission spectrum of the Nd₂O₃-modified YSZ coating after the thermal shock test produced a new emission peak at 594 nm, which decreased at 708 nm.     

Microstructure and luminescence properties of YSZ-based thermal barrier coatings modified by Eu2O3

In order to study the variation of rare earth oxides during thermal failure of thermal barrier coatings, Eu2O3-doped YSZ coatings with 0.5 mol%, 1.0 mol% and 1.5 mol% were prepared by explosive spraying. SEM, XRD, EDS and microhardness tester were used to analyze the effect of different rare earth oxide doping content on the morphology, composition and mechanical properties of the coatings. The results showed that with the increase of rare earth oxide doping content, the porosity of the coatings decreased, and the microhardness and fracture toughness increased. When the doping amount of rare earth oxide is 1.0 mol%, the bonding strength and thermal cycle times of the coating are the highest, 33.4 Mpa and 185 times respectively. With the increase of the doping amount of rare earth, the luminous intensity of the sprayed coating increases. After thermal shock test, the luminous intensity of Eu2O3-doped YSZ coatings at 592 and 608 nm decreased to a certain extent.     

The doping of reduced graphene oxide with nitrogen and its effect on the quenching of the material’s photoluminescence

N-doped graphene (NG) was synthesized by annealing reduced graphene oxide (RGO) in an ammonia atmosphere. The dependence of the nitrogen content on the annealing temperature and the type of doping of NG were investigated. The photoluminescence (PL) properties of the RGO and NG samples were studied. The results show that RGO exhibits strong ultraviolet (UV) PL at 367 nm. The PL of RGO can be quenched by doping it with N and the quenching efficiency depends on the pyridine N content.     

Sm2O3掺杂对纳米莫来石前驱粉体微观结构和烧结性能的影响

为了改善纳米莫来石粉体烧结性能,以硫酸铝和硅酸钠为主要合成原料,添加不同含量Sm2O3,采用共沉淀工艺制备莫来石前驱粉体,经过煅烧得到莫来石纳米粉体,研究了Sm2O3掺杂量对莫来石粉体微观结构和烧结性能的影响.研究表明:当Sm2O3的加入量为4wt%时,合成温度可由传统的1300 ℃左右降低至1000 ℃,晶粒尺寸约为39 nm,比表面积达到95.265 m2/g.说明适当掺杂Sm3+对于合成纳米莫来石具有改善微观结构,促进烧结,促进莫来石晶相形成的作用.     

载铁竹炭处理含磷废水的研究

对竹炭进行载铁改性,以增加其对磷的吸附能力并进行吸附法除磷.确定最佳改性质量浓度以及最佳处理条件,并考察改性竹炭的含铁量和铁的附着能力.最佳改性FeCl_3浓度为1.5 mol·L~(-1),最佳处理条件为pH为6～7,投配比为1:50(50mL磷废水投加竹炭1 g),吸附时间5 min以上,在此条件下,磷的去除率最高可达84.65%.该改性竹炭中铁质量分数为10.85%,脱附率为0.20%,表明铁层附着牢固.     

First Principles Modeling of Pd‐doped (La,Sr)(Co,Fe)O3 Complex Perovskites

(La,Sr)(Co,Fe)O₃ (LSCF) perovskites are well known promising materials for cathodes of solid oxide fuel cells. In order to reduce cathode operational temperature, doping on B‐sublattice with different metals was suggested. Indeed, as it was shown recently experimentally, doping with low Pd content increases oxygen vacancy concentration which is one of factors controlling oxygen transport in fuel cells. In this Communication, we modeled this material using first principles DFT calculations combined with supercell model. The charge density redistribution, density of states, and local lattice distortion around palladium ions are analyzed and reduction of the vacancy formation energy confirmed.     

SnO2:Sb透明导电薄膜的制备及光电性能

采用溶胶–凝胶法在玻璃基底上制备了Sb掺杂SnO2（SnO2：Sb）透明导电薄膜。研究了Sb掺杂量、镀膜次数、热处理温度对SnO2：Sb薄膜结构和光电性能的影响,利用X射线衍射仪、Fourier变换红外光谱仪、扫描电子显微镜、四探针电阻仪、分光光度计对薄膜样品进行表征。结果表明：SnO2：Sb薄膜为四方相金红石结构;薄膜结构平整、致密,膜厚与镀膜次数基本成线性关系;在Sb掺杂量为10%,镀膜8次的条件下,薄膜具有最佳的光电性能,方块电阻达105/□;在玻璃上镀SnO2：Sb薄膜后,近红外波段透过率下降显著,由90%降到5.5%,在可见光波段略有降低,仍保持了较高透过率。