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Y2O3纳米晶的制备和表征 总被引:12,自引:0,他引:12
采用硬脂酸凝胶法制备了Y2O3纳米晶,用傅立叶交换红外光谱(FTIR),热重-差热(TG-DTA)对制备过程进行了表征。用X射线末衍射(XRD),透射电子显策镜(TEM)及BET比表面吸附对Y2O3纳米晶的粒径和形貌进行一表征。在600℃以上热处理得到立方晶系Y2O3纳米晶,其粒径随热自理的上升而增大,形貌由球形变为立方形。粒径分布窄,无硬团聚现象产生,用傅立叶变换红外光谱(FTIR)对其谱学特性 相似文献
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本文以H2TiO3、H2O2、NH3、Pb(NO3)2为主要原料,用化学共沉淀法制备了纳米级PbTiO3。确定了反应物H2TiO3、H2O2、NH3的最佳摩尔比为1∶8∶2。用不同的退火温度和退火时间对样品处理得到相应粒径的纳米粉体,再由X射线和透射电镜对这些粉体进行了评估。并对反应的机理作了初步探讨。 相似文献
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溶胶—凝胶法制备纯PbTiO3超细粉的研究 总被引:8,自引:1,他引:7
以金属醇盐和无机盐为原料,用溶胶-凝胶法制备合成了粒径小于50nm的纯PbTiO3超细粉,探讨了溶胶-凝胶过程反应机理,并对制备过程中的一些主要因素如pH值、溶液浓度和温度等进行了讨论,采用热分析、X-Ray衍射分析和TEM等测试手段对PbTiO3超细粉进行了分析。 相似文献
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纳米MgO和MgAl2O4尖晶石的制备与表征 总被引:10,自引:0,他引:10
本文较详细地介绍了用无机盐Al(NO3)39H2O和Mg(NO3)2.6H2O为原料,醇凝胶分段程序升温超临界流体干燥法,制备纳米MgO和MgAl2O4尖晶石新型功能材料的方法,并对所制得的纳米粒子采用TEM、XRD和FT-R等现代分析测试手段进行了表面形貌、结构、晶型和组成等的表征,掌握了纳米粒子的一些特征。 相似文献
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化学共沉淀法制备纳米级PbTiO3粉末 总被引:4,自引:0,他引:4
本文以H2TiO3,H2O2,NH3,Pb(NO3)2为 要原料,用化学共沉淀法制备了纲米级PbTiO3,确定了反应物H2TiO3,H2O2,NH3的最佳摩经为1:8:2。用不同的退火温度和退火时间对样品处理得相应戏的纳米粉体,再由X射线的透射电镜对这些粉体进行评估。 相似文献
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纳米BaTiO3及其陶瓷材料的特殊物性的研究 总被引:1,自引:0,他引:1
报导了硬脂酸凝胶法制备的BaTiO3纳米晶及烧制的陶瓷材料的特殊物性,用X射线衍射、高分辨透射电镜、X荧光光谱、表面光电子能谱、介电谱、热释电谱研究了纳一粉及陶瓷材料的晶体结构,晶粒尺寸体相和表面相组份及铁电性能。结果表明,所有样品在室温下均为立方结构,没有铁电性,陶瓷样品在低温下具有铁电性。并发现纳米晶BaTiO3及陶瓷具有湿敏特性。 相似文献
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采用硬脂酸凝胶法制备了TiO2纳米材料,用差热-热重分析、红外光谱分析、X光衍射分析、透射电镜、表面光电压谱和X光光电子能谱等手段对TiO2制备过程及产物的晶型、形貌、表面光电特性等进行了分析。实验结果表明,TiO2纳米材料的表面结构有利于光催化活性的提高。 相似文献
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真空蒸镀硬脂酸包覆SnAgCu无铅焊料合金粉末研究 总被引:2,自引:0,他引:2
微细无铅焊料合金粉末易团聚和氧化,通过表面改性处理可提高其分散性及抗氧化性。本文以紧耦合气雾化法所制备的SnAgCu合金粉末为原料,采用真空蒸镀法对SnAgCu合金粉末进行包覆硬脂酸的改性研究,研究蒸镀温度、蒸镀时间等工艺条件对SnAgCu合金粉末改性效果的影响;采用扫描电镜(SEM)、透射电镜(TEM)对包覆后合金粉末的形貌及结构进行观测,采用X射线光电子能谱仪(XPS)和碳硫联测仪分别对包覆后粉末的光电子能量和C含量进行测试。研究结果表明:合适的真空蒸镀条件是蒸镀温度70℃,蒸镀时间12h,真空度低于1.6×10-2Pa,在此条件下可得到均匀致密、厚度为5~10nm的包覆层;硬脂酸包覆SnAgCu合金粉末遵循岛状生长机理,其包覆行为是物理吸附过程。 相似文献
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Xi Li Fabin Qiu Kui Guo Bo Zou Jianmin Gu Jing Wang Baokun Xu 《Materials Chemistry and Physics》1997,50(3):1105-232
Nanocrystalline Ba1−xSrxTiO3 (x=0, 0.2, 0.4, 0.6, 0.8 and 1.0) precursors were synthesized using the stearic acid gel method. After the precursors had been calcined at 600–950°C for 0.5–1 h, nanocrystalline powders with the cubic perovskite structure were obtained and these were made into thick films. The powder samples were characterized by differential thermal analysis, X-ray diffraction and transmission electron microscopy, and the thick film samples were characterized by scanning electron microscopy and X-ray diffraction. The humidity-sensitive properties of the nanocrystalline Ba1−xSrxTiO3 thick films were investigated. The results show that these nanocrystalline thick films possess higher humidity sensitivity and lower resistance than those of conventional materials. 相似文献
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Erdem E Matthes A Böttcher R Gläsel HJ Hartmann E 《Journal of nanoscience and nanotechnology》2008,8(2):702-716
Lead titanate (PbTiO3) micro- and nanocrystalline powders have been prepared from metallo-oranic precursor through combined polymerisation and pyrolysis (CPP). The enhanced liquid-precursor based version of the cpp route in combination with soft milling enables an adjustment of the mean particle size up to 5 nm. A multi-frequency (X, Q, and W band) electron paramagnetic resonance study of Cr-doped micro- and nanocrystalline PbTiO3 samples was performed. Three Cr3+ centers (C1, C2, and C3) with different axial Zero Field Splitting (ZFS) parameters were identified in microcrystalline samples. The center C1 is similar to that observed in previous X band single crystal and ceramic sample measurements. The superposition model by Newman and Urban was applied to translate the ZFS data of these centers into local Cr3+ displacements inside the distorted oxygen octahedra of the microcrystalline PbTiO3 lattice. In the nanocrystalline powders only the center C1 was observed. Its EPR spectra in dependence on the mean particle size were fitted using a spin-Hamiltonian in which a Gaussian distribution of ZFS terms was assumed. The variation of the mean value of ZFS parameter D and distribution width deltaD was determined and the critical particle size of the size-driven phase (tetragonal-cubic) transition was estimated. In nanocrystalline powders with mean particle size d < d(cr) the tetragonal C1 spectrum is not more detectable. A new Cr3+ center spectrum, C4, consisting of a single line with an isotropic g-factor is detectable allowing the cubic phase in the nanomaterials to be quantified. Further, temperature dependent EPR measurements were made which allowed the variation in Curie temperature with mean particle size to be determined. 相似文献
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以硬脂酸为粉末改性剂, 聚乙二醇/聚乙烯醇缩丁醛/聚甲醛(PEG/PVB/POM)为粘结剂体系制备锆钛酸铅镧(PLZT)粉末注射成形喂料, 并通过先水脱脂后烧结的工艺制备了PLZT压电陶瓷。研究了硬脂酸用量对粉末特性、喂料黏度、水脱脂率以及坯体强度的影响, 并对烧结后陶瓷的微观形貌与电性能进行对比与分析。结果表明:硬脂酸通过湿法改性成功包覆于PLZT粉体表面, 硬脂酸改性打破了粉末间的团聚, 且当硬脂酸包覆量为2wt%时, 喂料具有较低的剪切黏度及较高的坯体弯曲强度。但过量改性反而使得喂料黏度上升, 坯体弯曲强度下降。改性后的粉体在坯体内分散均匀, 烧结后的陶瓷晶粒生长完善, 具有更大的烧结致密度。与未改性的PLZT陶瓷相比, 在2 kV/mm极化电压下, 2wt%硬脂酸改性的PLZT的压电常数d33由638 pC/N提高为682 pC/N。 相似文献
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硬脂酸溶胶凝胶法制备氧化镁纳米微粒的研究 总被引:17,自引:0,他引:17
以硬脂酸为分散剂,采用溶胶凝胶法研究了制备氧化镁纳米微粒的条件,探讨了分散剂用量,反应时间,反应温度,烧结温度和时间对产物粒径与转化率的影响,取得了最佳工艺条件,分别用红外光谱(IR),X射线射末衍射(XRD),透射电镜(TEM)和比表面积(BET)测定,对该纳米微粒的结构与性能进行了表征,结果表明:Mg(NO3)2与CH3(CH2)16COOH的摩尔配比控制在1:1,于90℃反应20min,在470℃热处理3h,得到立方相氧化镁钠米微粒,形貌为椭球体,分散性好,平均粒径约为36nm. 相似文献