溶胶—凝胶法制备含PbTiO3微晶的玻璃陶瓷

采用溶胶－凝胶工艺低温合成含有Ｐｂ，Ｔｉ成份和玻璃相组成成份的均匀透明凝胶，并通过热处理在凝胶玻璃中原位生长出纯净的铁电ＰｂＴｉＯ３微晶。利用热分析手段和ＩＲ谱分析了凝胶在热处理过程中有机基团的分解及内部元素键合方式的演变。     

SiCpl/BAS玻璃陶瓷基复合材料的制备及力学性能

用溶胶凝胶法成功合成了理论钡长石凝胶玻璃,采用热压烧结工艺制备出均匀、致密的ＳｉＣｐｌ增强的ＢＡＳ玻璃陶瓷复合材料。并利用ＳＥＭ等设备以及显微压痕、三点弯曲等方法研究了ＳｉＣｐｌ／ＢＡＳ玻璃陶瓷基复合材料致密度的影响,探讨了ＳｉＣｐｌ对ＳｉＣｐｌ／ＢＡＳ的强韧化机理。     

Sol-Gel法制备B2O3-P2O5-SiO2系低介玻璃陶瓷

采用溶胶－凝胶法,以正硅酸乙酯和硼酸、磷酸为原料,制备出一种ＢＰＳ超细粉．使用这种超细粉,可在低于９５０℃空气气氛中烧结,获得性能优良的低分电常数、低损耗玻璃陶瓷．该种材料的介电常数ε≤５、介电损耗ｔａｎδ＜３×１０^－３（１ＭＨｚ）,有望用于超高频叠层片式电感领域．     

Sol-Gel法制备B2O3-P2O5-SiO2系低介玻璃陶瓷

采用溶胶-凝胶法,以正硅酸乙酯和硼酸、磷酸为原料,制备出一种BPS超细粉．使用这种超细粉,可在低于950℃空气气氛中烧结,获得性能优良的低介电常数、低损耗玻璃陶瓷．该种材料的介电常数ε≤5、介电损耗tanδ<3×10     

溶胶—凝胶法制备PCT铁电陶瓷

本文报导了通过溶胶－凝胶法制备Ｐｂ１－ｘＣａｘＴｉＯ３（ｘ＝０．１￣０．３）铁电陶瓷原料粉末，所得粉末具有较高的活性、纯度和均匀度。研究了不同掺ＣａＯ量对晶体结构和烧结温度的影响。在ＰＣＴ晶相生成前未发现有烧绿石或其它过渡晶相的出现。使用该粉末通过１０００￣１２００℃的烧结过程，所得ＰＴＣ陶瓷可达理论密度的８８￣９４％。     

溶胶—凝胶法制备PCT铁电陶瓷

本文报导了通过溶胶—凝胶法制备Ｐｂ_（１－ｘ）ＣａｘＴｉＯ_３（ｘ＝０．１～０．３）铁电陶瓷原料粉末，所得粉末具有较高的活性、纯度和均匀度。研究了不同掺ＣａＯ量对晶体结构和烧结温度的影响。在ＰＣＴ晶相生成前未发现有烧绿石或其它过渡晶相的出现。使用该粉末通过１０００～１２００℃的烧结过程，所得ＰＣＴ陶瓷可达理论密度的８８～９４％。     

复相功能玻璃陶瓷及其溶胶-凝胶法制备

阐述了复相功能玻璃陶瓷的各种类型和制备方法,通过对溶胶－凝胶工艺的深入分析,指出溶胶－胶工艺是制备复相功能玻璃陶瓷的有效方法,该方法容易获得不易团聚、呈较高且热力学稳定的功能晶相,也可实现晶体尺寸大小的控制且不易产生杂相。     

Si-B-O系BST玻璃陶瓷制备及介电弥散研究

采用硝酸钡、硝酸锶、钛酸丁酯、正硅酸乙脂和硼酸三正丁脂为原料的溶胶凝胶方法制备了Si-B-O系BaxSr1-xTiO3玻璃陶瓷。通过差热分析(DTA)、热失重(TG)、X射线衍射(XRD)分析Si-B-O系BST玻璃陶瓷超细粉体合成过程及其相结构变化。采用X射线衍射(XRD)、扫描电子显微镜(SEM)描述Si-B-O系BST玻璃陶瓷烧结体的相结构和显微组织结构变化。阻抗分析仪测量Si-B-O系BST玻璃陶瓷的-50～100℃介电温谱。实验结果表明：Si-B-O系BST玻璃陶瓷粉体的相结构为立方钙钛矿相结构,其合成温度为700℃．不存在第二相。Si-B-O系BST玻璃陶瓷的烧结温度低于传统工艺。Si-B-O系BST玻璃陶瓷的显微结构呈细晶结构。Si-B-O系BST玻璃陶瓷的介电常数ε随着烧结温度升高而增大．介电损耗tgδ随测试温度的增加而降低。随着晶粒平均尺寸的减小．Si-B-O系BST玻璃陶瓷样品的介电峰变低．平坦．宽化．存在介电峰弥散化的现象。     

BaFe12O19／Al2O3—SiO2—K2O微晶玻璃陶瓷的柠檬酸Sol—Gel合成及其微波性能的研究

采用柠檬酸sol-gel工艺合成了BaFe12O19/Al2O3-SiO2-K2O微晶玻璃陶瓷，并对其介电常数及其磁导率在1MHz～6GHz下的变化规律进行了研究。结果表明，BaFe12O19/Al2O3-SiO2-K2O微晶玻璃陶瓷的合成与体系中Fe/Ba、烧结温度密切相关；其介电常数、磁导率基本都随测试频率的增加而下降；介电损耗值最大可达到0.30，磁损耗值较小。     

Ba2TiGe2O8 and Ba2TiSi2O8 pyroelectric glass-ceramics

Pyroelectric glass-ceramics of composition Ba₂TiGe₂O₈ and Ba₂TiSi₂O₈ were prepred by crystallizing the glasses in a temperature gradient. High pyroelectric responses up to 50% of the single-crystal values were observed because of the high degree of orientation of the crystallites in the glass-ceramic samples. The piezoelectric and dielectric properties of the glasses and the glass-ceramics are also consistent with the properties of the single crystals.     

飞秒激光诱导玻璃内Ba2TiSi2O8晶体的析出

使用聚焦后的800nm,150fs,250kHz的高重复频率飞秒脉冲激光器能够在BaO-TiO₂-SiO₂组分的玻璃内部三维选择性地诱导Ba₂TiSi₂O₈晶体的析出. 发光光谱显示这种晶体把入射的800nm光转化成了400nm的蓝光,因此这种析出的晶体具有非线性倍频特性. 通过拉曼光谱测定,在当前的玻璃组分中析出的晶体是Ba₂TiSi₂O₈. 研究表明,经250kHz的飞秒激光辐照一段时间后,在玻璃内部由于脉冲能量的连续沉积会使得激光辐照区域出现热积累效应,因此,该辐照区域的温度会不断升高以致超过玻璃析晶温度,最终诱导玻璃熔融析晶. 此外,对飞秒激光辐照区域不同部位进行拉曼光谱检测,结果表明：在整个区域Ba₂TiSi₂O₈晶体的析出呈现中间比外围明显的分布特点,因此晶体析出与辐照形成的温度梯度场有密切关系.     

Pyroelectricity and related properties in the fresnoite pseudobinary system Ba2TiGe2O8-Ba2TiSi2O8

Complete solid solubility is found in the pseudobinary system Ba₂TiGe₂O₈-Ba₂TiSi₂O₈ by studies on ceramics and single crystals (Czochralski technique). The spontaneous birefringence perpendicular to the polar axis of the orthorhombic low temperature phase has been measured versus temperature and silicon contents: the temperature of the phase transition of species 4mmFmm2 is of second order and decreases from 1103 K at 0 at % Si to about 400 K at 40 at % Si. The pyroelectric coefficient in the orthorhombic mm2 and the tetragonal 4 mm phase is of the order of 10^–6 C m^–2 K^–1 in the entire system and has a positive temperature coefficient for all compositions studied except for Ba₂TiGe₂O₈, in which the pyroelectric coefficient changes sign at about 308 K. The spacegroup of the orthorhombic phase is proposed to be C _2v ¹¹ -Cmm2.     

Microstructural characterization of grain-oriented glass-ceramics in the system Ba2 TiSi2O8-SiO2

In polycrystalline fresnoite, advantage of the piezo- and pyroelectric properties can be taken only if texturing along its polar [0 0 1]-axis can be achieved. We report on a novel technique to prepare grain-oriented glass-ceramics in the system fresnoite-SiO2 by electrochemically induced nucleation. Optimum conditions for grain orientation were determined by characterizing the microstructure of glass-ceramics prepared at 1150, 1200 and 1350 °C using electron microscopy and X-ray texture goniometry. At 1150 °C—due to the smallest crystal growth rate and highest nucleation rate—the most distinct orientation is obtained. The solidification of the glass-ceramic consist of three subsequent steps. First, dendritic fresnoite crystallizes most rapidly along its [0 0 1]-axis with [1 1 0] facet planes. Due to growth selection, the polar {c}-axes become oriented. Secondly, within the interdendritic areas, the pseudo-binary eutectic fresnoite-silica solidifies lamellarly. Finally, in the middle of the interspaces, a crystalline barium silicate coexisting with glassy silica is formed at 1200 °C and 1350 °C. At 1150 °C, however, a glass with the composition of the melt solidifies.     

Addition of Ba2TiSi2O8 to manganese-doped barium titanate: effect on oxygen diffusion and grain-boundary composition

The effect of barium titanium silicate additions to pure and manganese-doped barium titanate was studied by high-temperature conductivity and analytical electron microscopy. The results show that this addition precipitates during cooling as a second crystalline phase with only a small amount of amorphous phase left in a few grain boundaries. The secondary crystalline phase incorporates excess manganese left from the heterogeneous doping of barium titanate.     

Preparation and properties of Tl2Ba2CaCu2O8 thin films

Anex situ process has been developed to produce thin superconducting Tl₂Ba₂CaCu₂O₈ films. The properties of films grown on different substrates using different annealing regimes were studied. Critical temperatures of 103–107 K were measured on films prepared in a broad range of annealing temperatures on SrTiO₃, LaAlO₃, and Y-ZrO₂ substrates. A critical current density,J _c, of 2×10⁶ A/cm² at 77 K was measured on LaAlO₃. Film morphology was studied by SEM, AFM, and STM.     

亚微米Li2O-Al2O3-SiO2微晶玻璃制备

本文利用DTA、XRD和SEM对Li2O-Al2O3-SiO2(以下简称LAS)微晶玻璃核化晶化热处理制度及氟离子在该玻璃体系中的作用进行研究.通过分析得出:含氟LAS玻璃核化温度和晶化温度分别为620℃和710℃,比相同组份的不含氟Li2O-Al2O3-SiO2玻璃核化、晶化温度分别降低了40℃和160℃左右;引入氟离子明显降低LAS玻璃析晶温度,系统的活化能降低约54kJ/mol,当含氟LAS玻璃的核化时间为1h、晶化时间为4hrs,平均微晶颗粒尺寸在50nm左右.     

氧化锆/锌硼硅微晶玻璃的制备与研究

在锌硼硅玻璃中添加0％～20％（wt）的超细部分稳定氧化锆粉体，分别采用熔融法和烧结法制备氧化锆／锌硼硅微晶玻璃。通过对实验现象的观测与分析，发现采用烧结法可以较好地制备氧化锆／锌硼硅微晶玻璃。采用X射线衍射仪观测玻璃样品中的晶相组成，用烧结点试验仪测试微晶玻璃的半球温度，通过维氏硬度计在玻璃表面的压痕尺寸计算微晶玻璃的韧性。结果表明，在ZnO-B2O3-SiO2玻璃中添加部分稳定超细ZrO2后，微晶玻璃的烧结温度升高，韧性得到很大的改善。     

SiO2-Na2O-CaO-P2O5-Fe2O3铁磁微晶玻璃的制备与性能研究

铁磁性微晶玻璃由于具有磁性和生物活性,可以用作磁感应热疗的热种子材料.采用SiO2-Na2O-CaO-P2O5-Fe2O3五元系统,通过共沉淀-熔融法和熔融法两种不同的方法制备铁磁性微晶玻璃,利用XRD确定其晶相并计算晶体的晶格常数和晶粒尺寸,并通过VSM表征样品的磁性能.结果表明,玻璃液在自然冷却的过程中就形成了大量的磁铁矿,不经过热处理过程即可制得具有磁铁矿唯一晶相的铁磁性微晶玻璃并具有生物活性.共沉淀-熔融法制备的样品磁性更强.     

(Ca,Sr,Ba)3V2O8的制备和发光性能研究

采用微波辅助溶胶-凝胶法制备了自激发钒酸盐A3(VO4)2(A:Ca,Sr,Ba)。采用X射线衍射仪、傅里叶变换红外光谱仪、扫描电镜、透射电子显微镜、荧光谱仪对样品各项参数进行了表征,研究了A3(VO4)2的光致发光特性,探讨了不同制备工艺条件对其发光性质的影响。实验结果表明,Sr3V2O8样品发光强度随退火温度而变化,在680～900℃时,其发射光谱强度随温度上升而单调下降,达到1000℃时开始上升;pH值为4时,样品的发射光谱强度最大。