共查询到20条相似文献,搜索用时 109 毫秒
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采用草酸盐化学共沉淀法制备了草酸氧钛锶钡前驱体,通过905℃高温煅烧,制得了高纯纳米钛酸锶钡,并利用SEM、TEM、FT-IR和XRD对其进行了表征;并将该粉体应用于水中重金属镉离子的吸附.结果表明:该法合成的钛酸锶钡粉体为球形,钙钛矿结构,平均粒径为36 nm.对水中的镉离子具有较强的吸附能力,其吸附量与介质的pH值有密切关系,吸附动力学符合Langmuir和Bangham速率方程所描述的规律;吸附等温线较好地符合Langmuir和Freundlich等温方程,吸附行为是自发的、放热的物理吸附过程. 相似文献
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本文以熔融的无水混合碱作为溶剂,以成本低廉的金属无机盐和氧化物作为反应物,成功制备了钛酸锶钡纳米陶瓷粉体.用XRD、SEM对粉体进行了表征.研究结果表明,在温度200℃,加热24h时生成钛酸锶钡(Ba0.77 Sr0.23 TiO3)粉体,在温度245℃,加热24h生成钛酸锶钡(Ba0.6 Sr0.4 TiO3),合成产物为四方形,粉体的粒径为60~120nm,粒度分布均匀. 相似文献
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BaTiO3材料因具有高介电常数及铁电、压电等特性广泛用于功能陶瓷等领域外,还因其具有高白度、高反射率等特点而在生物医药及干式诊断等领域也存在着潜在应用。本文介绍了均一粒径的球形BaTiO3超细粉体的制备技术,简述了水热法、溶胶-凝胶法、沉淀法等制备技术的优势与不足,并对近年来兴起的新合成方法——传统湿化学联用法、新技术-湿化学联用法、全新湿化学合成法作了简要论述。具有操作简便、工艺简单、原料低廉易得等优势的沉淀法仍具有工业化发展前景,在此基础上的超重力沉淀制备技术可得到球形BaTiO3超细粉体,利于后续工业化生产;而微通道技术有望制备得球形BaTiO3超细粉体,其发展前景可观。对于新技术合成BaTiO3机理还需深入研究;目前对均一球形BaTiO3超细粉体的研究大多处于实验室小规模生产,其工业放大生产所需合成装置有待进一步探索。 相似文献
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《Ceramics International》1986,12(3):161-171
The literature is reviewed to summarize methodologies for synthesizing metal alkoxides applicable as organic precursors to high-purity, well-characterized ceramic powders. Typical examples of preparation techniques, patents, and commercial manufacturing methods are provided, and special precautions noted. Basically, metal alkoxide synthesis is determined by the electronegativity of the metal concerned; synthetic routes may lead directly from the metal or a metal halide, or may be indirect, involving alcoholysis. 相似文献
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鉴于纳米陶瓷在工业生产和日常生活中的广泛应用,综述了近年来柠檬酸与金属离子配位形成纳米陶瓷的研究进展。对柠檬酸络合法制备纳米陶瓷的反应机理和反应流程进行简要介绍,并对今后此类方法合成纳米陶瓷研究的发展方向进行了展望。 相似文献
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The properties of optically transparent ceramic materials made of yttrium oxide and yttrium — aluminum garnet were analyzed. The promise of preparing a transparent ceramic that combines both of these compounds was demonstrated. Methods of synthesizing yttrium oxide and yttrium — aluminum garnet were examined. Selection of the method of synthesis was substantiated. The possibility of creating such materials without modifying additives was confirmed. 相似文献
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Fine grain α-phase silicon nitride (Si3N4) ceramic powders were produced via carbothermic reduction of colloidal SiO2, which contained pre-mixed additives of sintering aids primarily consisting of oxides such as MgO and Y2O3. The powders that were pre-mixed in the starting reactants were chosen based on the final powder composition and on type and amount of the secondary phases desired for sintering. After synthesizing, powder properties were examined using standard characterization techniques (XRD, SEM, BET, etc). This technique of ceramic synthesis has advantages in providing nitride-based ceramic powders, which contain secondary in situ phases that are distributed as sintering additives. Silicon nitride ceramic powders synthesized using this method might therefore be readily sintered because the homogeneously distributed sintering additives were present in the starting materials. In this work, the processing parameters are described in terms of the synthesis conditions. 相似文献
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Z. Kovziridze D. Aneli N. Nizharadze G. Tabatadze D. Gventsadze 《Glass Physics and Chemistry》2007,33(3):262-265
This paper reports on the results of investigations aimed at synthesizing ceramic materials with a high mechanical strength, as well as with high thermal and chemical resistances to corrosive media. The methods used for one-stage preparation of barite-based ceramic and polymer composites with these properties are considered. 相似文献
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Weiyou Yang Fengmei Gao Huatao Wang Xiangming Zheng Zhipeng Xie Linan An 《Journal of the American Ceramic Society》2008,91(4):1312-1315
A significant challenge in synthesizing nanowire/nanobelt-reinforced ceramic nanocomposites is to uniformly disperse these reinforcements. Here, we report the synthesis of amorphous silicon carbonitride powders containing in situ- formed single-crystal Si3 N4 nanowires and nanobelts via the catalyst-assisted pyrolysis of a polymeric precursor. The nanowires/nanobelts are uniformly dispersed within the powder matrix. The ratio of nanomaterials to powder can be controlled by tailoring the experimental conditions. The novel powders could be useful for fabricating nanowire/nanobelt-reinforced ceramic nanocomposites. 相似文献
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氮化硼纤维先驱体聚合物的合成及其表征 总被引:3,自引:0,他引:3
以三氯化硼与氯化铵为基础原料合成了三氯环硼氮烷(TCB),然后将TCB和三氯化硼分别与甲胺反应制得TCB的衍生物(CH3NH)3N3B3H3和B(NHCH3)3单体,将这些衍生物混合后在一定条件下进行缩合反应得到氮化硼先驱体。从合成方法、反应机理及其产物的结构性能表征等方面研究了氮化硼陶瓷纤维的先驱体,并且用IR、NMR、EA.XRD及DSC等表征方法对先驱体的结构、成分及性能进行了分析。结果表明:先驱体中含有B、C、N、H元素,存在CH3、B-N、N—H、G—H、BN六元环等结构单元。最后,对此先驱体进行了试纺丝,并用扫描电镜观察了所得纤维的形态。 相似文献