微波固相法合成纳米氧化镁

以乙酸镁和草酸为原料,用微波固相法制备了立方晶系结构的纳米氧化镁.TGA对前驱体的热分析表明微波处理能降低分解温度.采用XRD、TEM和IR对不同制备条件下MgO的晶型、晶粒尺寸、以及表观形貌等进行了表征,结果表明:焙烧温度、时间、微波加热时间对粒径影响较大;在600℃下焙烧3h制备的MgO平均晶粒尺寸为14.33nm.     

变形量对热压/热变形纳米复合Nd_9Fe_（84.5）Co_1B_（5.5）永磁体晶粒尺寸和矫顽力的影响

采用热压/热变形工艺制备纳米复合Nd9Fe84.5Co1B5.5永磁体,研究了热变形过程中的变形量对磁体平均晶粒尺寸的影响以及由此带来的晶间相互作用和矫顽力的变化。结果表明变形量54%的磁体中的硬、软磁性相的平均晶粒尺寸分别为61.0和51.8nm,与其热压状态时的两相平均晶粒尺寸（52.1和54.0nm）接近;而变形量74%的磁体中的硬、软磁性相的平均晶粒尺寸则分别显著减小至19.2和22.4nm。随着两相晶粒尺寸的显著细化,磁体中的晶间相互作用由以静磁耦合作用为主转变为以晶间交换耦合作用为主,这导致其矫顽力提高了64%。     

钛酸锶铅纳米陶瓷粉的制备及其烧结致密化行为

采用化学共沉淀法制备了一系列(Sr1-xPbx)TiO3陶瓷粉体,通过差热-热重(DTA-TG)分析确定了共沉淀产物的煅烧温度.X射线衍射(XRD)分析表明,化学共沉淀产物基本上呈非晶态,随后煅烧过程中发生晶化,主晶相为立方(Sr1-xPbx)TiO3固溶体.随着Pb含量的增加,逐渐出现游离的四方PbTiO3次晶相.所制得的(Sr1-xPbx)TiO3粉体具有纳米晶粒及纳米颗粒结构,平均晶粒及颗粒尺寸分别为20～30 nm和20～50 nm;颗粒形貌为不规则球形,团聚较为严重,以一次团聚颗粒为主,平均直径为200 nm,较大的二次团聚体平均粒径约为750 nm.纳米粉体烧结成瓷的温度显著降低,在1 150℃烧结基本实现致密化,而且由烧结前的立方相为主完全转变为四方相,没有了游离的PbTiO3并存在铁电畴亚结构.     

Nd8.5Dy0.5Fe84.5Co0.5B6合金的晶化工艺

本文采用熔体快淬法制备了纳米微晶Nd8.5Dy0.5Fe84.5Co0.5B6合金,对不同晶化工艺条件下的合金进行了显微组织分析、X射线衍射物相分析和磁性能分析,通过研究该合金的非晶晶化法制备纳米微晶的工艺参数,确定了该材料的最佳晶化工艺:750℃下保温0.5小时,获得平均晶粒尺寸为50nm左右,磁性能优良.     

射频PECVD法高压快速制备纳米晶硅薄膜

采用传统的射频等离子体增强化学气相沉积技术,在较高的工作气压(133～266Pa)下,以0.4nm/s速率制备出优质的氢化纳米晶硅薄膜.薄膜的晶化率约60%,平均晶粒尺寸约6.0nm,暗电导率为10-3～104/Ω·cm.红外吸收谱显示,薄膜中没有Si-O、Si-C、Si-N等杂质键,随晶化率的提高,Si-H键也逐渐消失.     

化学气相沉积法制备超纳米金刚石薄膜

采用微波等离子体化学气相沉积法,利用CH4、SiO2和Ar的混合气体在单晶硅片基底上制备出高质量的超纳米金刚石薄膜.表征结果显示,制备的薄膜致密而均匀,晶粒平均尺寸约7.47nm,表面粗糙度约15.72nm,并且其金刚石相的物相纯度相对较高,是质量优异的超纳米金刚石薄膜材料.     

氧化铟锡纳米晶薄膜的制备及其电致变色性能EI

采用一锅法合成不同形貌、尺寸的氧化铟锡(ITO)纳米晶,并通过旋涂工艺制备ITO纳米晶薄膜,研究不同形貌、尺寸ITO纳米晶制备的薄膜的近红外光谱调控性能。结果表明:5次旋涂后,ITO纳米晶薄膜的可见光透过率为89.2%,电阻率为54Ω·cm。平均直径为(6.88±1.53)nm的均匀球形ITO纳米晶制备的薄膜表现出最优的近红外光谱调控能力,在施加±2.5 V电压后,其在2000 nm的光谱调制量为39.3%,光密度变化量为0.43。在电致变色前后,ITO纳米晶薄膜始终保持高可见光透过率。ITO纳米晶的电致变色是由于电子注入/脱出导致的局域表面等离子体共振(LSPR)频率和强度变化引起,其电致变色过程是通过电容充放电实现的。     

掺硼对超纳米金刚石薄膜的影响

采用微波等离子体化学气相沉积(MPCVD)技术,利用氩气、甲烷、二氧化碳混合气体,制备出平均晶粒尺寸在7.480 nm左右,表面粗糙度在15.72 nm左右的高质量的超纳米金刚石薄膜;在此工艺基础上以硼烷作为掺杂气体,合成掺硼的金刚石薄膜.表征结果显示在一定的浓度范围内随着硼烷气体的通入,金刚石薄膜的晶粒尺寸及表面粗糙度增大、结晶性变好,不再具有超纳米金刚石膜的显微结构和表面形态;同时膜材的物相组成也发生改变,金刚石组份逐渐增多,并且膜层内出现了更明显的应力以及更好的导电性能.     

纳米晶NbMoTaW难熔高熵合金薄膜力学性能及其热稳定性

目的研究高熵合金薄膜的形貌、结构、力学性能和热稳定性,并探究其潜在的应用价值。方法选取不同厚度的纳米晶NbMoTaW难熔高熵合金薄膜作为研究对象,通过直流磁控溅射制备薄膜样品,采用扫描电子显微镜(SEM)、原子力显微镜(AFM)进行薄膜形貌观测,利用能谱分析仪(EDS)和X射线衍射(XRD),对薄膜成分和结构进行分析,采用高分辨透射电子显微镜(HR-TEM)观测内部结构,利用纳米压痕仪和真空退火炉进行力学性能和热稳定性的检测。结果 NbMoTaW高熵合金薄膜为单相BCC结构,表面形貌和晶粒尺寸随薄膜厚度的变化而变化,随着薄膜厚度的减小,其硬度先增加后减小,在膜厚为250 nm时出现最大值(16.0 GPa)。薄膜经过800℃、2 h的真空退火后,晶粒尺寸没有明显长大,同时硬度也没有明显下降,呈现出良好的热稳定性。结论成功制备出热稳定性优异的纳米晶NbMoTaW难熔高熵合金薄膜,并通过调控薄膜的厚度来改变晶粒尺寸,从而研究高熵合金薄膜结构与性能之间的联系。     

Mn∶ZnS胶体纳米晶的结构及光谱性质研究

利用一种绿色的合成工艺,采用巯基乙酸作为配体,在水溶液中成功合成了水溶性的Mn∶ZnS纳米晶,并研究了掺杂浓度对Mn∶ZnS纳米晶的结构及光谱性质的影响。XRD结果表明,合成的Mn∶ZnS纳米晶呈立方闪锌矿结构,通过谢乐公式估算的样品的平均晶粒尺寸约为2.1nm;随着掺杂浓度的增加,产物的晶胞参数逐渐减小,表明Mn离子已经掺入到ZnS纳米晶中,该发现与EDX结果相吻合。FT-IR光谱发现,配体巯基乙酸成功包覆在纳米晶的表面。Raman图谱进一步证实,Mn∶ZnS纳米晶为立方闪锌矿结构。UV-Vis吸收谱表明,不同掺杂浓度Mn∶ZnS纳米晶的吸收峰均随粒径的减小向短波长方向移动,通过吸收峰计算的纳米晶平均粒径为2.3nm。     

钇稳定氧化锆薄膜的制备及其微细加工

以甲醇为溶剂,硝酸氧锆、硝酸钇为前驱物,采用溶胶-凝胶方法,通过引入化学修饰剂乙酰丙酮(AcAcH),使乙酰丙酮和锆离子形成螯合物,得到了具有紫外光感光性的溶胶及其凝胶薄膜,提出了YSZ薄膜的微细图形加工新方法.UV-Vis.分光光度计的紫外光谱测试结果表明:乙酰丙酮与锆离子形成的螯合物在室温、可见光、大气环境下,可以存在于凝胶薄膜中,并具有较好的热稳定性和光化学稳定性,其紫外光谱的特征吸收峰大约在310nm附近;325nm紫外激光光源照射凝胶薄膜,能破坏、分解凝胶薄膜中的这种螯合物结构,使凝胶薄膜的物理化学性质发生变化,实验发现,经过紫外激光照射的凝胶薄膜在适当的有机溶剂(如甲醇等)中的溶解度和溶解速度显著降低,利用这一特性,采用325nm紫外激光通过掩膜照射凝胶薄膜,并在适当的有机溶剂中溶洗掉未受照射的区域,经过800℃,20min热处理,得到了具有微细图形的YSZ薄膜,XRD测试表明该薄膜相结构为立方相.     

YSZ thin films deposited by e-beam technique

YSZ thin films were grown evaporating cubic and tetragonal phase ZrO₂ stabilized by 8 wt.% of Y₂O₃ (8% of YSZ) ceramic powders by using e-beam deposition technique. Operating technical parameters that influence thin film properties were studied. The influence of substrate crystalline structure on growth of deposited YSZ thin film was analyzed there. The YSZ thin films (1.5-2 μm of thickness) were deposited on three different types of substrates: Al₂O₃, optical quartz (SiO₂), and Alloy 600 (Fe-Ni-Cr). The dependence of substrate temperature, electron gun power, and phase of ceramic powder on thin film structure and surface morphology was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The substrate temperature was changed in the range of 20-600° C (during the YSZ thin film deposition) and its influence on the crystallinity of deposited YSZ thin films was analyzed. It was found that electron gun power and substrate temperature has the influence on the crystallite size, and texture of YSZ thin films. Also, the substrate has no influence on the crystal orientation. The crystallite size varied between 20 and 40 nm and increased linearly changing the substrate temperature. The crystal phase of evaporated YSZ powder has the influence on the structure of the deposited YSZ thin films.     

片式氧传感器电解质薄膜的制备及其性能研究

确定了钇掺杂稳定氧化锆超细粉料和有机添加剂组成的浆料的配比,流延并烧结成了用于片式氧传感器的陶瓷薄膜。通过浆料粘度变化分析了分散剂的作用效果,研究了粘结剂和增塑剂对成膜效果和素坯相对密度的影响;采用综合热分析仪等手段研究了浆料中有机添加剂的烧除温度和热失重变化,并设计了合适的烧结制度;利用X射线衍射(XRD)及电子扫描显微镜(SEM)分析了最终烧结体的晶体结构和微观形貌;测量了抗热震及电性能。研究结果表明:素坯薄膜相对密度达55%,素坯内颗粒分散均匀,无硬团聚;采用相应的烧结制度在最佳烧结温度1450℃下得到了相对于理论密度达98%,晶粒均匀,晶界明显,几乎没有气孔的致密化薄膜;其抗热震性能达45次以上,电性能良好,是用于片式氧传感器的理想薄膜材料。     

YSZ薄膜Sol-Gel法制备及其结构分析

本文应用Sol－Gel方法制备了YSZ薄膜,研究了工艺条件对薄膜微观结构的影响.实验发现：基片的选择和清洁、样品的凝胶化速度、热处理过程中的升降温速率等是影响薄膜开裂的几个主要因素．XRD和SEM分析结果表明：应用Sol－Gel方法制备的YSZ薄膜,热处理温度须达800℃以上才能完全排除其中的酸根、有机基因和碳元素,且形成完整的立方相结构．薄膜经500℃、1h热处理后,其表面呈明显的海绵状结构．随着烧结温度的升高,薄膜表面变得致密,气孔明显减少,至1050℃时,薄膜表面光滑、无裂纹、无针孔、圆球形的小颗粒均匀分布．薄膜与衬底的结合紧密,薄膜厚度均匀,膜厚约为1.0μm.     

Sol-gel processing of yttria-stabilized zirconia films derived from the zirconium n-butoxide-acetic acid-nitric acid-water-isopropanol system

A stable yttria-stabilized zirconia (YSZ) sol has been synthesized by the controlled hydrolysis of zirconium n-butoxide. Acetic acid and nitric acid were used as chelating agent and catalyst, respectively. The addition of acetic acid and increasing the amount of nitric acids to the system significantly enhanced the sol stability. The viscosity of YSZ sol with the concentration less than 0.80 mol/ was independent on the shear rate, whereas those with the concentration over 1.2 mol/ showed shear-thinning behavior. The reduced viscosity of YSZ sol had linear relationship with sol concentration. These rheological behaviors are attributed to the polymeric nature of YSZ sol. XRD diffractograms of calcined YSZ xerogel confirmed that fully stabilized cubic zirconia phase was formed at a temperature as low as 600°C. Spin coating of YSZ sol on Si substrate followed by heat treatment at 600°C for 2 h in air produced uniform crack-free YSZ films of 70–135 nm thickness.     

微波调谐铈钇共掺Ba0.6Sr0.4TiO3薄膜的改性机制研究

用改进的溶胶一凝胶法制备光滑致密的预晶化铈（Ce）和锰（Mn）共掺钛酸锶钡（CeMn—SST）薄膜。电容－电压曲线表明,随着薄膜厚度的增加,综合介电性能大幅度改善,8层薄膜显示介电常数约为1300、低于0．007介电损耗、高于58％调谐率及接近180优质因子等优化介电性能,为主要沿（1101晶面层状生长的钙钛矿结构。     

High quality ZnO films deposited by radio-frequency magnetron sputtering using layer by layer growth method

Three-layered ZnO films were deposited on Si substrates by radio-frequency magnetron sputtering using layer by layer growth method. The Raman scattering confocal analysis confirms that ZnO film quality is improving at increasing the number of ZnO layers at film deposition.Applied method of deposition was used to realize homoepitaxial growth of ZnO films on c-Al₂O₃, Si, SiN_x/Si, glass and ITO/glass substrates. In order to improve the film quality we increased the number of deposition stages up to 5. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmittance measurements were used to testify the quality of grown five-layered ZnO films. XRD results showed that all five-layered ZnO films have (002) texture. The second order diffraction peak (004) on XRD spectra additionally testifies to the high quality of all five-layered ZnO films. SEM results demonstrated that no defects such as cracks and dislocations caused by interruption of deposition ZnO films were observed. Transmittance measurement results showed that ZnO films deposited on transparent substrates have abrupt absorption edge and high optical transmission in the visible region of the spectrum.     

Yttria stabilized zirconia thin films by multilayer electron-beam deposition

A new method for preparing cubic stabilized zirconia thin films was studied. The method involves the electron-beam deposition of an oxide multilayer film on suitable substrates followed by aging. Yttria-zirconia multilayer films on two electrodes, molybdenum and platinum/rhodium were investigated and the cubic stabilization was determined by X-ray diffraction and dc conduction studies. Cubic yttria stabilized zirconia (YSZ) was clearly formed on the molybdenum electrode but the solid solution formed on the platinum/ rhodium may be predominantly tetragonal as little or no cubic stabilization resulted. The formation of YSZ on molybdenum may be due to more favorable epitaxial growth conditions on that electrode.     

Synthesis and characterization of nanostructured nickel oxide thin films prepared with chemical spray pyrolysis

Nickel oxide thin films have been deposited in an open atmosphere onto glass substrates by chemical spray pyrolysis using aqueous nickel acetate solutions and air as driving gas. The films show a strong variation in the surface morphology depending on the substrate temperature and the precursor solution flux. At 350 °C substrate temperature, a reticular tissue-like film morphology is obtained, becoming the reticular nickel oxide fibres of the film thicker with increasing precursor solution flux. At 450 °C substrate temperature, the film growth rate is 4 times slower and a highly symmetric self-ordering of the material at nanometer length scale occurs. These films consist of interconnected grains separated by pores, both of about 100 nm in size. XRD and TEM revealed that the films are cubic NiO, being the crystallite size around 10 nm. The optical band gap of the films decreases strongly for increasing film thickness from 4.3 eV to 3.65 eV.     

Synthesis of LaCrO3 films using spray pyrolysis technique

LaCrO₃ thin films on electrolyte yttria-stabilized zirconia (YSZ) substrates were prepared by spray pyrolysis technique in the temperature range of 600–750 °C using lanthanum and chromium nitrates as precursors. Thin films obtained at 600–650 °C appear to be a mixture of cubic La(OH)CrO₄ and cubic LaCrO₄ phases, which transforms to pure cubic LaCrO₄ with the substrate temperature increasing to 700–750 °C. After being annealed at 900 °C for 2 h, all films convert to a single cubic LaCrO₃ phase. The change of Cr2p spectra in X-ray photoelectron spectroscopy (XPS) analysis shows the similar phase transformation process. Reaction processes with respect to the substrate temperature were proposed according to X-ray diffraction (XRD) and XPS analysis. The surface morphology of the films was found to depend strongly on the substrate temperature, which would be the deciding factor of the film growth mechanisms.