共查询到20条相似文献,搜索用时 156 毫秒
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以Ni(NO3)2·6H2O、Al(NO3)3·9H2O、ZrOCl2·8H2O和Ce(NO3)3·6H2O为原料,采用共沉淀法分别制备了NiO/CeO2/γ-Al2O3和NiO/CeO2-ZrO2/Al2O3催化剂.通过X射线衍射(XRD)、透射电子显微镜(TEM)和近边X射线吸收精细结构(XANES)等方法对催化剂的组成结构进行表征.结果表明,煅烧温度高于600℃时,NiO/CeO2/γ-Al2O3催化剂中的NiO与γ-Al2O3载体发生作用,形成NiAl2O4尖晶石;而NiO/CeO2-ZrO2/Al2O3催化剂中,NiO能够稳定存在,没有NiAl2O4尖晶石生成,且Al2O3与CeO2和ZrO2作用形成一种新的Zr0.30Ce0.45Al0.25O1.87固溶体. 相似文献
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以[AlO4Al12(OH)24(H2O) 12]7+(简写为Al13)溶液为铝源, 采取湿化学的方法合成尖晶石及尖晶石氧化锆复合粉体. 采用27Al NMR、DSC-TG、XRD和FTIR等研究前驱体结构、反应过程及微结构演变. 将氯化镁、氢氧化钠混合研磨后加入Al13溶液中, 得到由Mg6Al2CO3(OH)16·4H2O 和 β-Al(OH)3组成的前驱体, 经过600℃煅烧形成尖晶石, 更高温煅烧产物仍为尖晶石单相. 以Al13、MgCl2·6H2O和ZrOCl2·8H2O为原料制备的前驱体经600℃煅烧, 同样获得尖晶石和四方相氧化锆. Al13粉末和尖晶石氧化锆复合粉体的FTIR谱显示, 归属于[AlO6]的吸收谱带由608cm-1移至 601cm-1, 归属于 [AlO4] 的吸收谱带由761cm-1 移至 723cm-1. 前驱体中形成的AlOMg键合是以Al13为铝源合成尖晶石和尖晶石氧化锆复合粉体具有低温合成的主要原因. 相似文献
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高透光率Nd:YAG透明陶瓷的制备与性能研究 总被引:5,自引:0,他引:5
以Y(NO3)3·6H2O、Al (NO3)3·9H2O、(NH4)2SO4和Nd(NO3)3为原料, NH4HCO3为沉淀剂, 以TEOS作为添加剂, 采用共沉淀法制备出Nd:YAG前驱体粉体; 前驱体经过1200℃煅烧5h后, 得到分散性好, 颗粒近似球型、纯YAG立方相的Nd:YAG纳米粉体, 其平均粒径约为100nm. 煅烧后的粉体压制成素坯, 在1700~1800℃煅烧10h, 可获得透光性良好的Nd:YAG激光透明陶瓷, YAG晶粒的平均尺寸为15μm, 晶界处和晶粒内没有杂质、气孔存在, 无散射中心. 1.5mm厚的样品在近红外波长为1064nm处透过率为83.5%, 基本接近于透明Nd:YAG晶体的理论值. 相似文献
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介绍了用溶胶 凝胶方法制备Pb(Zr0 .53Ti0 .4 7)O3(PZT)铁电薄膜的工艺流程。以硝酸锆、醋酸铅和钛酸四丁酯为原料 ,在 90 0℃ ,30min退火条件下制备了硅基PZT铁电薄膜。实验分析结果显示 ,PZT铁电薄膜的晶化很完善。研究了PZT铁电薄膜与硅之间的界面及其对铁电薄膜品质的影响。并在此基础上实现了制备PZT铁电薄膜的低温改进工艺。 相似文献
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氯离子与铟离子的总浓度比对铟锡氧化物前驱体氢氧化物)粒径的影响 总被引:1,自引:0,他引:1
用络盐法制备了铟锡氧化物(ITO)纳米粉末. 通过对铟和锡的络合盐[(NH4)2InCl5·H2O和(NH4)2SnCl6]的制备研究, 证实了反应初始溶液中络离子的存在. 通过调节氯离子与铟离子的总浓度比研究了络离子对ITO前驱体(氢氧化物)粒径的影响. 提出了络离子对纳米ITO粉末粒径的影响原理: 络离子的存在, 降低了反应初始溶液中游离In 3+和Sn 4+的浓度, 有利于纳米级ITO粉末的生成. 通过XRD和激光粒度仪对ITO前驱体(氢氧化物)进行了表征. 相似文献
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连续离子层吸附与反应法(SILAR)生长ZnO多晶薄膜的研究 总被引:1,自引:0,他引:1
采用连续离子层吸附与反应法(SILAR),以锌氨络离子([Zn(NH3)4]2+)为前驱体溶液,在玻璃衬底上沉积了ZnO薄膜,以XRD和SEM等手段分析了薄膜的晶体结构和表面、断面形貌,考察了空气气氛下的退火过程对ZnO薄膜晶体结构与微观形貌的影响,并初步探讨了以SILAR方法沉积ZnO薄膜的机理.结果表明,经200次SILAR沉积循环,所得ZnO薄膜为红锌矿结构的多晶薄膜,沿<002>方向择优生长;薄膜表面致密、光滑均匀,厚度约800nm.退火处理使ZnO薄膜氧缺位减少,晶粒沿c轴取向增强;随退火温度升高,锌间隙原子增加;500℃退火时,ZnO薄膜发生再结晶.减小前驱体溶液的[NH3·H2O]/[Zn2+]比率可提高ZnO薄膜生长速率. 相似文献
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通过傅立叶红外吸收光谱(FTIR)、1H和13C核磁共振波谱(NMR)对制备PZT铁电薄膜的Sol-Gel化学反应过程进行了分析.结果表明,采用硝酸氧锆(ZrO(NO3)2·2H2O)为锆源并使用单一溶剂制备PZT铁电薄膜,溶胶-凝胶化过程中化学反应相对简单,多组分系统稳定性较高,工艺条件易于控制,所制备的Pb(Zr0.53Ti0.47)O3铁电薄膜致密性好,晶粒尺寸小且分布均匀. 相似文献
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共沉淀法合成ZrO2-ZrW2O8复合材料的工艺研究 总被引:1,自引:0,他引:1
以硝酸氧锆[ZrO(NO3)2·5H2O]和钨酸铵(H40N10O41W12·xH2O)为原料,采用共沉淀法合成了低热膨胀的ZrO2-ZrW2O8复合陶瓷, 着重研究了不同热处理条件对前驱体转变为ZrO2-ZrW2O8复合陶瓷的影响, 并探讨了前驱体生成及其转变的反应历程. 通过X射线衍射仪(XRD)、热重-差示扫描量热(TG-DSC)、扫描电子显微镜(SEM)、热膨胀仪等分析手段对样品的晶体结构、物相转变、断面微观形貌和热膨胀性能进行表征. 结果表明: 采用共沉淀法制备的前驱体在1150℃热处理2h可以合成高纯度、混合均匀的ZrO2-ZrW2O8复合陶瓷; 随烧结时间的延长, ZrW2O8衍射峰半高宽逐渐减小, 晶粒在不断长大; ZrO2-50wt%ZrW2O8复合陶瓷在30~600℃内的平均热膨胀系数为-3.2295×10-6K-1. 相似文献
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新型Sol-Gel技术PZT铁电厚膜的制备及电学性能研究 总被引:3,自引:0,他引:3
采用新型sol-gel技术在 Pt/Ti/SiO2/Si基片上制备出了厚度为 2~60μm的PZT铁 电厚膜材料;研究了PZT厚膜的结构及其介电、铁电性能.XRD谱分析显示,PZT厚膜 呈现出纯钙钛矿相结构,无焦绿石相存在.SEM电镜照片显示,PZT膜厚均匀一致,无裂 纹、高致密.厚度为50μm的PZT厚膜的介电常数为860,介电损耗为0.03,剩余极化强度 是25μC/cm2.矫顽场是40kV/cm. 相似文献
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Drying temperature effects on microstructure, electrical properties and electro-optic coefficients of sol-gel derived PZT thin films 总被引:2,自引:0,他引:2
Transparent lead zirconium titanate (PZT) thin film is suitable for a variety of electro-optic application, and the increasing of the electro-optic coefficient of PZT film is one of the important factors for this application. In this study, the main processing variable for improving an electro-optic coefficient was the drying temperature: 300, 350, 450 and 500°C in sol-gel derived PZT thin films. The highest linear electro-optic coefficient (1.65×10−10 (m/V)) was observed in PZT film dried at 450°C. The PZT film showed the highest perovskite content, polarization (Pmax=49.58 μC/cm2, Pr=24.8 μC/cm2) and dielectric constant (532). A new two-beam polarization (TBP) interferometer with a reflection configuration was used for electro-optic testing of PZT thin films which allows measurement of the linear electro-optic coefficient of thin film with strong Fabry–Perot (FP) effect usually present in PZT thin film. 相似文献
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HNO3处理对TiO2纳米薄膜的光催化活性和表面微结构的影响 总被引:1,自引:0,他引:1
通过sol-gel工艺分别在钠钙玻璃和预涂SiO2涂层的钠钙玻璃基体上制备了TiO2。光催化纳米薄膜.然后用1mol/L HNO3水溶液对煅烧后的薄膜进行酸处理.用X射线光电子能谱(XPS)、扫描电镜(SEM)和紫外可见光谱(UV-VIS)对酸处理前后TiO2纳米薄膜进行了表征.用甲基橙水溶液的光催化脱色来评价TiO2薄膜的光催化活性.结果表明:SiO2涂层能有效阻止钠离子从玻璃基体向TiO2薄膜的扩散;普通玻璃表面的TiO2纳米薄膜经HNO3处理后,薄膜的光催化活性明显增强.这是由于TiO2纳米薄膜中的钠离子浓度降低以及表面羟基含量增加的缘故. 相似文献
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通过将溶胶凝胶法制备的锆钛酸铅(PZT)在非晶态和多晶态进行刻蚀,对比未经刻蚀的PZT性能,研究了集成工艺中湿法刻蚀造成极化和耐久性能退化的机理.PZT的结晶图谱和表面形貌分析发现,湿法刻蚀中产生的非铁电成分由于具有较小的介电常数,降低了铁电材料上分担的有效测试电压,导致刻蚀后PZT极化能力的降低.未刻蚀的PZT翻转1011次后极化值损失约3%,而刻蚀后极化值减小量大于5%.随着尺寸的减小,耐久特性的降低更为明显,100μm×100μm的PZT极化值减小量约为500μm×500μm样品的3倍.高温过程中由于湿法刻蚀而产生的缺陷和空隙在PZT内部重新分布,外加电压下有更多的电子被缺陷和空隙束缚而产生内建电场并钉扎铁电畴,不同器件尺寸的PZT内部缺陷和空隙浓度的变化不同,导致耐久特性随PZT器件尺寸而不同.利用压电特性参数与极化强度的关系,可以解释湿法刻蚀对压电特性造成损伤的原因. 相似文献
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Auger spectroscopy was used to study the compositional change in the interfacial region between ferroelectric thin films, namely lead strontium titanate (PST) and lead zirconate titanate (PZT), and commercially available Si substrates with a 200 nm thick thermal oxide layer. Both PST and PZT thin films were prepared via a sol-gel spin coating method. The thin films from both materials were annealed under the same conditions (temperature and time). It was found that strontium stops the lead diffusion into SiO2 by forming SrSiO3/Sr2SiO4 and SrO, maintaining a well defined SiO2 region, while PbSiO3 is formed in the PZT/SiO2 system. These results are important for a general understanding of interdiffusions in material interfaces in particular for the realization of future high-dielectric-constant (high-k) oxide layers and for the next generation of advanced electronic devices. 相似文献
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Ba0.7Sr0.3TiO3薄膜的制备、结构及性能研究 总被引:2,自引:0,他引:2
研究了一种以乙二醇为稳定剂的新的BST前驱液,用sol-gel法在Pt/Ti/SiO2/Si(100)基底上成功地制备出具有优良电学性能的Ba0.7Sr0.3 TiO3薄膜.乙二醇的加入有效地增加了前驱液的稳定性,并降低薄膜的结晶温度.利用XRD、DTA等技术分析了凝胶热处理过程中相变化情况及薄膜厚度与成相的关系.厚度 200nm,O2气氛中 700℃处理 15min后的 BST薄膜具有良好的介电性能,100kHz时介电常数ε>400,介电损耗 D<0.02;P—E电滞回线说明薄膜具有良好的铁电性能,剩余极化只约为1.4μC/cm2,矫顽场强 Ec约为 48kV/cm. 相似文献
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Tsuda H. Nakada M. Akedo J. Ohashi K. 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2008,55(5):975-979
The optical properties and related band structure of ferroelectric lead zirconate titanate [PZT, Pb(Zr0.6Ti0.4)O3] films prepared on glass substrates at room temperature by aerosol deposition were investigated. The reflectance and transmittance of the PZT films were measured in the wavelength range from UV to near-infrared. The measured optical spectra were analyzed using dielectric function models that describe optical transitions in the band gap region. Optical absorption of the as-deposited PZT films was found to be larger than that of the annealed PZT films in the near-infrared wavelength range. The analyzed results indicated that post-deposition annealing increased the band gap energy of the PZT films, corresponding to a decrease in optical absorption. 相似文献
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Longhai Wang Jun Yu Yunbo Wang Junxiong Gao 《Journal of Materials Science: Materials in Electronics》2006,17(7):509-514
The PbZr0.3Ti0.7O3(PZT) thin film and multilayer PbZr0.3Ti0.7O3/PbTiO3(PZT/PT), PbTiO3/PbZr0.3Ti0.7O3/ PbTiO3(PT/PZT/PT) thin films were prepared by a Sol-Gel method on the Pt(111)/Ti/SiO2/Si(100) substrate for FeRAM application. The microstructure, ferroelectric, fatigue, dielectric, and leakage current properties
of these thin films were investigated. The results indicate that the multilayer PT/PZT/PT thin film have a better ferroelectric,
fatigue, dielectric and leakage current density properties. Its remanent polarization Pr reaches a maximum value of 21.2 μC/cm2 and the coercive field Ec gets to a minimum value of 64.2kV/cm. After 1010 cycles, it still has more than 80% remnant polarization. The PT/PZT/PT thin film exhibits lower dielectric constant and lower
dielectric loss, which is beneficial for FeRAM application. It also has the lowest leakage current density. The leakage current
mechanism of the PZT, PZT/PT and PT/PZT/PT thin films is correlated to the microstructure and can be modeled in terms of GBLC
and SCLC theory. The microstructure and electric properties of these films are correlated. The double-sided PT seed layers
enhance not only the microstructure but also the electric properties. It is evident that the PT/PZT/PT multilayer thin film
is a promising candidate for FeRAM application. 相似文献