共查询到19条相似文献,搜索用时 93 毫秒
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以溶胶-凝胶法制备了BaTiO3基PTCR纳米陶瓷粉体,通过适当控制材料的掺杂量和烧成制度达到细化晶粒、降低烧结温度及降低室温率的目的。讨论了溶胶.凝胶过程中水的加入量、乙酸加入量、乙醇加入量、成胶温度对形成细晶粉体的影响,制备出的BaTiO3粉体具有纯度高、粒径小、均匀性好、活性高、热处理温度低等优点。R-T丁曲线表明1260℃较1240℃烧结具有高的升阻比、温度系数,低的电阻率、居里温度:XRD分析表明所得粉体与BaTiO3主峰相吻合;800℃预烧2h所得BaTiO3粉体的TEM图表明粉体分布较均匀、外形为近似球形,其平均晶粒尺寸约30nm左右,与XRD得到的晶粒相当,单个颗粒是单晶;1240℃下烧结所得样品的SEM图片看出样品的平均晶粒约1~2μm、晶粒较为均匀致密。 相似文献
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采用四甲氧基硅和氯化镁为前躯体,通过溶胶-凝胶和高温水热法合成了内径5nm~10nm,外径约15nm~35nm,长度400nm~2μm的纤蛇纹石纳米管,利用X射线衍射仪(XRD)、扫描电子显微镜(FSEM)和高分辨透射电子显微镜(HRTEM)对合成样品的物相、形貌和结构进行了表征;初步试验表明,纤蛇纹石纳米管的形成过程是氢氧化镁优先在一维方向上生长成针状或纤维状结构,在溶液中形成结构导向模板后与非晶态的二氧化硅反应形成纳米管状结构;通过控制化学计量比在一定范围内可以实现纳米管的内外径尺寸的调控。 相似文献
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以表面孔径为0.1μm的α-Al2O3陶瓷管为支撑载体,以硝酸锰和硝酸锂为主要原料,先采用水热法进行预成膜,再采用溶胶-凝胶法复合制备膜状含锂锰氧化物,利用XRD和SEM对合成产物进行表征,并进行单一气体渗透性能测试.结果表明,合成产物为膜状的锂离子筛前驱体LiMn2O4;膜的表面连续致密,没有明显的晶间孔和裂缺,膜厚度约为1 μm;室温下膜对H2的渗透率为1.09×10-6mol·s-1·m-2·Pa-1,H2/N2的理想分离因数达3.63,具有较好的选择分离性.研究结果为基于锂离子筛膜的连续化海水提锂技术开发提供了材料支撑. 相似文献
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以硝酸铅、氧氯化锆、钛酸四丁酯为反应物前躯体,氢氧化钾为矿化剂,采用水热法合成PZT粉体.系统研究了反应温度、反应时间、矿化剂浓度和引入表面活性剂聚乙烯醇(PVA)对PZT晶体生长的影响.通过XRD和SEM对粉体进行了表征,探索出制备PZT粉体的最佳条件,研究结果表明:在KOH浓度为2 mol/L、180℃反应12 h的条件下可制备得到粒径约为1μm,粒径均匀,晶体发育完整的钙钛矿结构的PZT粉体;在该反应体系中加入适量PVA时得到了棒状纤维结构的粉体. 相似文献
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采用溶胶-凝胶工艺成功地制备了纯钙钛矿结构的Pb(Mg1/3Nb2/3)0.65Ti0.35O3(简称PMNT)弛豫型铁电陶瓷薄膜,分析了溶胶先驱体中铅含量对PMNT薄膜钙钛矿结构稳定性的影响规律,表明热退火过程的氧化铅气氛层覆盖技术对获得纯钙钛矿结构PMNT薄膜材料至关重要,系统测试了纯钙钛矿PMNT薄膜材料的铁电和介电性能,提出弛豫型铁电PMNT陶瓷薄膜制备中晶粒自由结晶和异常生长动力学机制. 相似文献
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以硝酸铅、氧氯化锆、钛酸四丁酯、氢氧化钾和氨水为原料,以乙醇和水的混合液为溶剂,采用水热法合成Pb(Zr0.52Ti0.48)O3(PZT)压电陶瓷粉体。通过X射线衍射和扫描电镜对合成粉体进行表征,并研究Pb元素物质的量与Zr及Ti两种元素物质的量之和的比n(Pb)/n(Zr+Ti)和矿化剂KOH浓度对粉体物相和形貌的影响。结果表明:n(Pb)/n(Zr+Ti)=1.4时,可以合成单一晶相的PZT,颗粒的立方体形貌规则清晰且无团聚,结晶良好;在200℃、反应溶剂乙醇和水的体积比为2∶1、n(Pb)/n(Zr+Ti)=1.4的条件下,当KOH浓度由1 mol/L增加到4 mol/L时,立方体形貌的PZT粉体的粒径由1.5μm减小到0.2μm。 相似文献
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通过柠檬酸盐溶胶-凝胶法制备复合掺杂的BaTiO3基粉体,着重研究了凝胶煅烧工艺制度对制备纳米粉体的影响。最终确定了600℃为最佳煅烧温度,在此低温下煅烧干凝胶,并保温1h,再经二次掺杂混磨得到了晶粒20~70nm、分散性好的BaTiO3基纳米粉体。 相似文献
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本文分别以柠檬酸、草酸和EDTA为络合剂采用溶胶凝胶法制备了稀土钙钛矿型锰氧化物LaMnO_3。利用X射线衍射仪(XRD)、场发射扫描电镜(FE-SEM)、拉曼光谱仪(FIIR-Raman)和傅里叶变换红外光谱仪(FT-IR)对样品进行了表征。结果表明在700℃焙烧温度下均可制备出单相钙钛矿结构的LaMnO_3;以柠檬酸为络合剂制备的产物的晶粒大小及其分布比草酸和EDTA的要更均匀;升高焙烧温度或使用不同的络合剂会使钙钛矿结构从立方相转变为菱方相。 相似文献
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采用溶胶-凝胶法和浸渍提拉法成功制备了Al掺杂ZnO薄膜(以下简称AZO薄膜)。用X射线衍射仪(XRD)、场发射扫描电镜(FE-SEM)、分光光度计、霍尔(Hall)测量仪,分别研究了不同Al的掺杂浓度对薄膜的结晶性能、微观形貌和光电性能的影响,探讨了Al的掺杂机理。结果表明,Al的掺杂存在最佳值,当Al掺杂摩尔浓度为5%时,AZO薄膜的结晶性能、微观形貌和光电性能最佳,其透光率在80%以上,电阻率为2.1×102Ω·cm,霍尔迁移率为0.23cm2/V·s,载流子浓度为7.81×1014cm-3。 相似文献
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Huanting Wang Song Xie Wei Lai Xingqin Liu Chusheng Chen Guangyao Meng 《Journal of Materials Science》1999,34(6):1163-1167
Perovskite La0.6Sr0.4Co0.8Fe0.2O3– (LSCF) powders have been successfully synthesized from oxide and carbonates based on the principle of gelcasting. Phase-forming temperature is very dependent on the ball-milling process during the suspension preparation. As the ball-milling time is increased, the temperature of phase formation decreases, therefore the perovskite powder obtained has a larger Brunaver–Emmett–Teller (BET) specific surface area. The grain sizes were around 1 m at 1000°C and 2 m at 1100°C from scanning electron microscopy (SEM) photographs. The perovskite powders have good sinterability: the sintering densities of ceramic bodies shaped with as-prepared powders were investigated. SEM photos show that sintered ceramics exhibit a well defined morphology in the packing and sintering of particles. The oxygen permeance of disc shaped samples, with a thickness ranging from 1.02 to 1.98 mm was 6.39 × 10–8–1.99 × 10–8 mol cm–2 s–1 at 900°C indicating that LSCF ceramics have high oxygen permeation. It can be concluded that gelcasting is a simple and effective method for preparing practical multicomponent perovskite powders. 相似文献
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Ashwith Chilvery Sanjib Das Padmaja Guggilla Christina Brantley Anderson Sunda-Meya 《Science and Technology of Advanced Materials》2016,17(1):650-658
Perovskite solar cells (PSCs) were developed in 2009 and have led to a number of significant improvements in clean energy technology. The power conversion efficiency (PCE) of PSCs has increased exponentially and currently stands at 22%. PSCs are transforming photovoltaic (PV) technology, outpacing many established PV technologies through their versatility and roll-to-roll manufacturing compatibility. The viability of low-temperature and solution-processed manufacturing has further improved their viability. This article provides a brief overview of the stoichiometry of perovskite materials, the engineering behind various modes of manufacturing by solution processing methods, and recommendations for future research to achieve large-scale manufacturing of high efficiency PSCs. 相似文献
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In this article, a new synthesis process to fabricate PbTiO3/NiTi composite film is reported. A transitional PbTiO3 film, prepared on NiTi substrate by a hydrothermal reaction, was introduced to improve the adhesion strength of the composite. Then an outer PbTiO3 film was fabricated on the transitional layer by a sol-gel method. No cracks or obvious defects were observed on the outer ceramic film. Scratch tests showed that the adhesion strength of composite film was improved greatly by using this new synthesis process. 相似文献
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G. I. Kozlov 《Technical Physics Letters》1997,23(4):309-310
Gas-phase synthesis of titanium carbide powders is described. A thermodynamic analysis is made to optimize the process parameters.
Preliminary experiments were carried out using a system incorporating a cw gas-discharge multibeam CO2 laser and these demonstrated the advantages of the laser-chemical process over other methods.
Pis’ma Zh. Tekh. Fiz. 23, 37–41 (April 26, 1997) 相似文献