铌酸锶钡/钛酸锶钡复相陶瓷制备新工艺研究

本文以钛酸四丁酯等配制溶胶前驱体溶液,通过控制前驱体溶液中各组分的配比成功制备了粘稠的溶胶溶液,以悬浮传统固相烧结工艺制备的微米级铌酸锶钡陶瓷粉体,在超声分散等的作用下形成均匀凝胶,最后成功制备出复相陶瓷坯体。采用X射线及扫描电镜对其进行表征,同时对其制备工艺及烧结制度进行了分析。结果表明:此工艺具有工艺简单,成本低,两相固溶均匀,且在一定程度上能够抑制在烧结过程中晶粒异常长大等优点,为科研工作者提供了一条新的工艺路线。     

铌酸锶钡晶体铁电性能

用偏光显微镜确定了SrxBa1-xNb2O6单晶的光轴方向为z轴,并制备了3mm×5mm×0.45mm垂直于z轴的切片.在50Hz交频电场下,利用Sawyer-Tower电路,获得了较完整的电滞回线.检测并分析了SrxBa1-xNb2O6晶体切片的介电温谱以及相变特性,所测得的SrxBa1-xNb2O6晶体由铁电相转变成顺电相的特征温度Tm为74 ℃,这种晶体属于弥散性铁电相变.     

钛酸锶钡结构与制备工艺研究进展

钛酸锶钡[(Ba,Sr)TiO3,SBT]是1种重要的电子陶瓷材料,具有高介电常数、低漏电流、高热释电系数,高的介电可调等特性,广泛用于动态随机存储器、热释电探测器、介质移相器等电子元件的制备。综述了钛酸锶钡[(Ba,Sr)TiO3,SBT]的结构和制备工艺研究进展,评述了制备工艺和掺杂等对钛酸锶钡的结构和性能的影响,并指出了钛酸锶钡尚待解决的问题。     

钙铝硅氧化物/铌酸锶钡微晶玻璃的结构和介电性能

采用烧结法制备了CaO-A12O3-SiO2(CAS)/Sr0.6Ba0.4Nb2O6(SBN40)微晶玻璃,对其结构和介电性能进行了研究.随着SBN40含量的增加,CAS/SBN40微晶玻璃的密度逐渐增大,达到最大密度的温度开始略有下降,而当SBN40的含量(质量分数,下同)超过70%后显著升高.随SBN40含量的增加,主晶相依次从SiO2,CaNb2O6向SBN转变,到SBN40的含量为90%时,已经完全形成单相四方钨青铜.同时,在100kHz时,CAS/SBN40微晶玻璃的介电常数先缓慢增加而后剧增,介电常数与物相组成的变化密切相关.10?S/90%SBN40微晶玻璃是一种新弛豫铁电体,其介电常数达963,在80℃左右具有明显的介电弛豫峰.     

钨青铜结构偏铌酸铅高温陶瓷的制备工艺

本发明钨青铜结构偏铌酸铅高温陶瓷的制备工艺涉及高温压电陶瓷，包括采用纳米原料、压块与粉末复合以及高低温相结合的粉料合成工艺、改进球磨条件和多次混合现细磨、严格控制烧结温度、缩短保温时间以及适当的快冷速度、冷加工精度与增大极化功率等。采用本技术可使陶瓷粉料的制备量提高到10kg，并提高了陶瓷元件的体密度、绝缘电阻、压电性能及一致性等，同时也提高了产品的成品率，且技术简便、易于掌握。     

铌酸铅钡晶体及其低温相变

对于铝酸铅钡(PBN)系统中三种不同组份的晶体,研究了300K至10K范围内的介电和热电性能。发现它们在约50-70K发生铁电-铁电相变。相变温度上下晶体点群分别为4mm和m。在4mm相中,自发极化沿[001]方向,在m相中,自发极化在m面内。在降温过程中通过相变时,自发极化从[001]方向发生微小的偏离,但仍保持在一个m面,其方向用四方相的指数表示为[hhl]。     

水热合成技术的研究和应用──Ⅴ.锆酸锶、锆酸钡晶体粉末的制备研究

采用碱性前驱物Ba（OH）2或Sr（OH）2及两性前驱物ZrO（OH）2，水热合成BaZrO3和SrZrO3晶体粉末一系列实验结果表明，在水热温度为150-200℃，KOH浓度0.1～0．8mol／L，时间20～60min的条件下，均能有效合成。在相同的碱度下，延长水热时间或提高温度有利于SrZrO3、BaZrO3晶体粉末的合成、晶化、晶体长大和提高晶体完整性．推荐合成条件：在0．2mol/L的KOH介质中，200℃下水热处理1h文中提出了合成机理并对结果进行了讨论．     

雷奈酸锶的合成工艺优化

目的研究雷奈酸锶合成工艺中技术参数的优化。方法雷奈酸锶的合成有三个关键步骤,分别为氨基取代,中间体Ⅲ精制和水解成盐。由于最终产品无法进行重结晶精制,因此对氨基取代得到的中间体Ⅲ进行精制,从而控制最终产品的质量。结论通过对雷奈酸锶合成工艺进行优化,所合成的雷奈酸锶的质量大大提高,适合工业化生产。     

铌酸钾锂薄膜的制备方法与研究进展

铌酸钾锂具有良好的光电、压电及非线性光学性能,在集成光学、集成电路等领域具有广阔的应用前景.综述了近年来铌酸钾锂薄膜的制备方法与最新进展,同时对各种方法制备的铌酸钾锂薄膜的研究结果进行了综述,并指出了目前研究存在的问题及其发展趋势.     

雷尼酸锶的合成及制剂工艺分析

雷尼酸锶药物对于治疗骨质疏松具有较好的疗效,是骨质疏松类药物中常见的药物成分,在进行该物质的合成时,需要柠檬酸这种基本的材料,通过浓硫酸的氧化作用,生成丙酮二羧酸,将该物质通过酯化、环合、烷基化反映,从而生成雷尼酸四甲酯,通过水解成盐,得到雷尼酸锶。因此,在生产雷尼酸锶的过程中,需要经过合成工艺,最终形成成品制剂,在进行制剂管理的过程中需要对制剂合成情况进行实验,并对制施工的工艺进行分析,提出科学合理的合成与制剂方法。     

BST铁电薄膜的制备、应用及其研究进展

综述了钛酸锶钡（BST）铁电薄膜的4种制备工艺：磁控溅射（Magnetron sputtering）法、金属有机物化学气相沉积（MOCVD）法、脉冲激光淀积（PLD）法,以及溶胶-凝胶（Sol-Gel）法.并介绍了BST铁电薄膜在动态随机存储器、非致冷红外探测器热成像、移相器等方面的应用及其研究进展.     

八水氢氧化钡制取高纯碳酸钡的研究

介绍八水氢氧化钡制取高纯碳酸钡的工艺,产品质量及用户使用结果。     

八水氢氧化钡制取高纯碳酸钡

介绍八水氢氧化钡制取高纯碳酸钡的工艺、产品质量及用户使用结果。     

Preparation of Strontium Barium Niobate by Sol–Gel Method

Crack-free SBN (Sr_xBa_1-xNb₂O₆) thin films have been prepared by a sol–gel method with metal alkoxides. A homogeneous and stable precursor solution was obtained from Sr and Ba metal and Nb(OEt)₅ in ethanol with a key additive of ethoxyethanol. SBN (where x = 0.5) powder crystallized to orthorhombic phase at 700°C, and then transformed completely to tetragonal phase at 1200°C. The formation of tetragonal SBN was observed on sapphire (R) substrates at 700°C, whereas the tetragonal phase began to appear in the powders at 1000°C. SBN films with highly preferred orientation were successfully synthesized on MgO (100) substrates at 670°C.     

Low-Temperature Preparation and Size Effect of Strontium Barium Niobate Ultrafine Powder

Ultrafine strontium barium niobate ((Sr _x Ba_{1− x} )Nb₂O₆, SBN) powders were prepared using sol–gel and hydrolysis aging processes. Their structural properties were examined via X-ray diffractometry and Raman spectroscopy. Our results indicated that the SBN powders crystallize to a pure tetragonal phase at annealing temperatures as low as 700°C. The crystallite size of SBN powders subjected to different thermal treatments was in the range of several tens of nanometers. Differential scanning calorimetry revealed that the heat flow had a broadened peak. The transition temperature from the ferroelectric phase to the paraelectric phase and the relative dielectric constant of the SBN50 powder were less than the corresponding values of the bulk ceramic and the single crystal.     

铌酸锶钡/钛酸锶钡介电常数预测模型研究

首次应用粉末-溶胶工艺合成出铌酸锶钡/钛酸锶钡复相陶瓷(SBN/SBT)。以Clausius(克劳修斯)-Mosotti(莫索缔)方程为基础,采用混合对数法则,通过实验得到的复合材料的晶格参数和铌酸锶钡、钛酸锶钡的理论极化率,建立了描述铌酸锶钡/钛酸锶钡复相陶瓷的介电常数预测模型,通过数学模型得到的预测数值与实验数值吻合。     

Effect of the Strontium:Barium Ratio and Atmosphere on the Sintering Behavior of Strontium Barium Niobate

The sintering behavior of Sr _x Ba_{1− x} Nb₂O₆ (SBN) ( x = 0.5, 0.6, and 0.7) was studied. The densification rate increased and the evaluated activation energy of SBN decreased as the Sr:Ba molar ratio increased. Also, when SBN50 (SBN where x = 0.5) was sintered at <1300°C, the densification rate decreased as the oxygen partial pressure increased, and, at 1300°C, the oxygen partial pressure had insignificant influence on the densification. The relationship of sintering behavior and structure of SBN has been discussed, and the niobium ion was suggested as being the rate-limiting species when sintering SBN.     

Diffuse Phase Transition of Tantalum-Bearing Strontium Barium Niobate

The dielectric constants, ε' and ε", of tantalum-bearing strontium barium niobate (SBNT) ceramics were measured as functions of temperature and frequency. The phase transition of SBNT became ambiguous by adding Ta and the apparent Curie temperature determined from the maximum of ε' had a linear relation with the axial ratio c/a. A dielectric loss peak was observed in the phase transition region of SBNT, and its peak frequency increased with temperature. The loss peak was attributed to dielectric relaxation by the jump between two states with different polarizing directions as a preliminary phenomenon of the phase transition. A model based on the local variation from one unit cell to the next rather than the macroscopic compositional fluctuation in the crystal was proposed for the mechanism of diffuse phase transition.