BaTiO3铁电薄膜在硅基片上的取向生长

采用脉冲激光沉积方法,在硅基片上先沉积MgO或CeO2缓冲层后再制备BaTiO3(BTO)铁电薄膜.通过原位反射高能电子衍射来监测MgO,CeO2缓冲层在硅基片上的生长行为.用X射线衍射测定BTO薄膜的结晶取向.并利用压电响应力显微镜观察了铁电薄膜的自发极化形成的铁电畴.结果表明:BTO薄膜在不同的缓冲层硅基片上以不同的取向生长,在织构的MgO/Si(001)基片上为(001)择优,择优程度与MgO织构品质有关,其中在双轴织构MgO缓冲层上为(001)单一取向;在CeO2(111)缓冲层上为(011)单一取向.(001)取向的BTO薄膜具有更大的面外极化,而(011)取向的BTO薄膜具有更大的面内极化.     

双轴织构氧化铈薄膜的反射高能电子衍射分析

为了制备高温超导带材,采用直流反应磁控溅射在Ni-5%(摩尔分数)W衬底上制备双轴织构的CeO2薄膜用作缓冲层.通过反射高能电子衍射仪观察分析了双轴织构CeO2的衍射谱.选取某一衍射点,提取其衍射强度相对直入点的弧度分布,拟合半高宽得到其面外取向分布;旋转样品,对某～非对称晶面的衍射强度做摇摆分析,得到其面内取向分布,其结果均与x射线衍射分析结果较为吻合.在CeO2缓冲层上制备的YBa2Cu3O7薄膜的临界温度为88K,临界电流密度为1.2MA/cm2(77K).     

ZAO薄膜使用射频溅射法生长之参数的研究

以氧化铝锌陶瓷为溅射靶材,在氩气环境下,使用射频溅射法在玻璃基片上制备氧化铝锌(ZAO)薄膜。通过调节气体压强、基片温度、溅射功率制膜,得到以C轴(002)为选择取向的氧化锌薄膜。由XRD、原子力显微镜(AFM)等对薄膜进行分析。结果表明,制备薄膜的最佳条件为:溅射压强0.4 Pa,溅射功率200 W,基片温度300℃。     

平面磁控溅射氧化锌（ZnO）薄膜的几个问题

Ｃ轴取向一致的氧化锌（ＺｎＯ）薄膜是一种良好的压电材料。采用平面磁控溅射是制备ＺｎＯ薄膜较为理想的一种方法。为讨论溅射用靶体的掺杂、溅射功率和基片温度等问题，本实验溅射使用掺有２￣５ｗｔ％碳酸锂（Ｌｉ２ＣＯ３）的烧结陶瓷靶；溅射功率６００Ｗ左右；沉积薄膜基片温度３００℃，并注意其他有关条件的调节，对获得的薄膜用ＸＲＤ等方法评价性能。     

生长温度对激光分子束外延A1N薄膜的影响

采用激光分子束外延法在Al2O3基片上制备AlN薄膜。用反射高能电子衍射、X射线衍射和原子力显微镜研究沉积温度对薄膜微结构的影响,通过光致发光谱和透射光谱对六方AlN薄膜的光学性能进行研究。结果表明：沉积温度为450℃时,沉积的AlN薄膜为非晶态;沉积温度为650℃时,在Al2O3基片上得到c轴单一取向的的六方AlN薄膜,且AlN和Al2O3之间的外延匹配关系为AlN[1210]//Al2O3[1100],AlN[1100]//Al2O3[1210]和AlN（0001）//Al2O3（0001）,这种面内相对旋转30°,可以减小AlN薄膜与Al2O3基片之间的晶格失配度和界面能。此外,650℃沉积的AlN的透射率达到85%,禁带宽度为5.6 eV。沉积温度升高到750℃时,AlN薄膜的透射率和光学能隙变小     

射频磁控溅射法制备PI基CeO2-TiO2复合薄膜

采用射频磁控溅射技术在柔性基体PI(聚酰亚胺)上制备了纳米CeO2-TiO2复合薄膜.借助X射线衍射(XRD)、原子力显微镜(AFM)和紫外-可见光谱仪分别研究了薄膜的物相结构、表面生长形貌和薄膜的紫外-可见光透过率及光学能隙,并用WS-2000型薄膜划痕仪测定薄膜与基体的界面结合强度.实验结果表明:沉积态的薄膜为非晶态,经200℃退火处理4h后,转化为良好的晶态,薄膜中主要含有锐钛矿相结构;溅射功率对薄膜的形貌,光学性能及界面结合力均有影响.尤其当溅射功率为120W时,薄膜的综合性能最优;平均晶粒尺寸110nm,表面粗糙度为160nm,吸光率达80%,光学能隙Eg仅为(2.65±0.05)eV,划痕法测量涂层与基体的附着力为60N.     

Cu_3N薄膜制备及其性能研究

Cu3N薄膜的晶面取向、沉积速率、电学特性等性质除与制备方法有关外,还和制备工艺参数有很大关系。溅射法制备Cu3N薄膜工艺参数主要有,混合气体(N2+Ar)中氮气分压比r、基底温度T(℃)、溅射功率P(W)。为了研究Cu3N薄膜的性能与其制备工艺参数之间关系,本文采用反应射频磁控溅射法,在玻璃基底上成功制备了Cu3N薄膜,并研究了工艺参数对其晶面取向、膜厚、电学性能、沉积速率的影响。     

射频溅射参数对CO-Cr膜取向的影响

用于垂直磁记录的 Co-Cr 膜是采用射频(RF)溅射的方法沉积的。几个最重要的溅射参数,即RF 溅射电压 VRF、氩气压力 Par 和基片保持器温度 Tsh,决定着磁化垂直取向的最佳值。其晶体结构在各种参数变化的范围内总是 hcp(六方密排—译注)。如果不使用最佳溅射参数,则会观察到 C 轴沿膜面取向的附加 h■p 化合物(an additional hcp compound)。这种取向会使平面剩磁 S■=(Mr/Ms)增加。我们对溅射参数引起的基片温度变化进行了测量,发现只有在 Ts 大约150℃时才能获得纯粹的 C 轴垂直取向。若因改变 Tsh 或溅射条件而导致改变 Ts 的取值,结果就会出现 C 轴沿膜面取向的附加 hcp 化合物。因此认为 Ts 对于 Co-Cr 膜的溅射是一个相当重要的参数。     

磁性薄膜生长的元胞自动机模拟

采用原子嵌入势,用元胞自动机方法模拟了铁(001)面上的薄膜生长。研究了溅射原子的沉积、迁移扩散和再蒸发3个主要的过程。发现溅射功率和基底温度对薄膜表面所形成岛核的形态影响很大,定量计算了当溅射功率和基底温度变化时岛的均匀度。给出了对于实验有指导意义的结论。     

射频磁控溅射法在玻璃上制备紫外吸收和透明导电双功能薄膜

制备了SnO2:Sb(6%,摩尔分数)靶材和一系列不同摩尔比的CeO2-TiO2靶材;以所制靶材用射频磁控溅射法在普通玻璃基片上沉积了CeO2-TiO2单层和CeO2-TiO2/SnO2:Sb双层薄膜.用紫外-可见光谱、Raman光谱、X射线光电子能谱和X射线衍射对CeO2-TiO2薄膜进行了表征.结果表明:在CeO2/TiO2摩尔比为0.5:0.5和0.6:0.4时沉积得到的CeO2-TiO2薄膜为非晶态结构,并具有高的紫外吸收(平均值＞99%)和高的可见光透过率(平均值＞80%).在CeO2-TiO2薄膜表面存在Ce4 ,Ce3 和Ti4 .对CeO2-TiO2/SnO2:Sb双层薄膜,除具有高的紫外吸收(平均值＞99%)和可见光透过率(平均值＞75%)性能外,还具有导电性,方块电阻在80～90 Ω/口之间,电阻率在(3.2～3.6)×10-3Ω·cm之间.该双层镀膜玻璃具有截止紫外线和透明导电双功能.     

CuO and CuO-ZnO catalysts supported on CeO2 and CeO2-LaO3 for low temperature water-gas shift reaction

This paper describes an investigation on CuO and CuO-ZnO catalysts supported on CeO₂ and CeO₂-La₂O₃ oxides, which were designed for the low temperature water-gas shift reaction (WGSR). Bulk catalysts were prepared by co-precipitation of metal nitrates and characterized by energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), surface area (by the BET method), X-ray photoelectron spectroscopy (XPS), and in situ X-ray absorption near edge structure (XANES). The catalysts' activities were tested in the forward WGSR, and the CuO/CeO₂ catalyst presented the best catalytic performance. The reasons for this are twofold: (1) the presence of Zn inhibits the interaction between Cu and Ce ions, and (2) lanthanum oxide forms a solid solution with cerium oxide, which will cause a decrease in the surface area of the catalysts. Also the CuO/CeO₂ catalyst presented the highest Cu content on the surface, which could influence its catalytic behavior. Additionally, the Cu⁰ and Cu¹⁺ species could influence the catalytic activity via a reduction-oxidation mechanism, corroborating to the best catalytic performance of the Cu/Ce catalyst.     

(锌、铜、锰)复合脱硫剂的制备及性能研究

用共沉淀法制备纳米脱硫剂前躯物,以硅铝酸盐为载体造粒成型,经450℃煅烧6h得到三元金属氧化物脱硫剂,此脱硫剂在240℃无氧条件下精脱H2S,且颗粒平均直径为1.0mm时,其穿透硫容可达33.5%,是一种适合于中低温条件下脱硫的脱硫剂。     

金属氧化物吸收微波辐射的能力与其结构的关系

考察了８种金属氧化物及６种复合金属氧化物在微波场中的升温行为，并对升温行为与其结构的关系进行了初步探讨。     

中国专用氧化镁开发现状及其发展建议

介绍了氧化镁系列产品应用领域及生产现状,中国专用氧化镁如活性氧化镁、电工级氧化镁、硅钢级氧化镁、高纯氧化镁等开发是成功的,其中高纯氧化镁已达到世界领先水平;硅钢级氧化镁不仅已工业化,并成功应用于武钢硅钢片的生产上,取得显著经济效益,但总体上看研发技术虽然成功,工业化生产量还不足。提出了中国专用氧化镁发展必须充分利用中国十分丰富镁资源,扬长避短,发挥原料及生产方法优势,采用先进设备,提升装置及自控水平,建立万吨级骨干企业,提高专用化率等建议,提高精细氧化镁品种及产量以满足国内外市场需求。     

Sintering of Zinc Oxide Doped with Antimony Oxide and Bismuth Oxide

The phase change, densification, and microstructure development of ZnO doped with both Bi₂O₃ and Sb₂O₃ are studied to better understand the sintering behavior of ZnO varistors. The densification behavior is related to the formation of pyrochlore and liquid phases; the densification is retarded by the former and promoted by the latter. The pyrochlore phase, whose composition is Bi_3/2ZnSb_3/2O₇, appears below 700°C. The formation temperature of the liquid phase depends on the Sb/Bi ratio: about 750°C for Sb/Bi < 1 by the eutectic melting in the system ZnO—Bi₂O₃, and about 1000°C for Sb/Bi > 1 by the reaction of the pyrochlore phase with ZnO. Hence, the densification rate is determined virtually by the Sb/Bi ratio and not by the total amount of additives. The microstructure depends on the sintering temperature. Sintering at 1000°C forms intragrain pyrochlore particles in ZnO grains as well as intergranular layers, but the intragrain particles disappear at 1200°C by the increased amount of liquid phase, which enhances the mobility of the solid second phase.     

非水解溶胶-凝胶过程制备锡/硅复合氧化物

以无水四氯化锡和正硅酸乙酯为前驱物、环己烷为溶剂,在无氧无水条件下采用非水解溶胶-凝胶过程制备了锡/硅复合氧化物,并对其进行了表征分析。结果表明,在原料Sn/Si摩尔比为1∶2、反应温度为30℃、焙烧温度为500℃时,所得复合氧化物的产率为31.3%,Sn/Si摩尔比为7.4∶1,粒径10nm左右,比表面积22.58cm2.g-1,平均孔径14.3nm,比孔容0.047cm3.g-1,主要为颗粒堆积孔;复合氧化物的主要组成为无定形氧化硅和氧化锡晶体,在焙烧温度达到500～600℃时仍有Sn-O-Si杂键存在。     

纯正黑色釉的研制

研究了用金属氧化物和硅酸盐材料直接制取纯正黑色釉的可行性，探讨了氧化铁、氧化铝、氧化钢、氧化信和氧化锰对黑釉性质的影响。     

氧化钛对氧化铬材料烧结特性的影响

以Cr_2O_3微粉和TiO_2微粉为主要原料,聚乙烯醇为结合剂,经制浆、喷雾造粒、机压和等静压二次成型,在气氛炉内(氧分压分别控制在10Pa和0.1Pa),1 500℃保温3h烧成制备氧化铬样品.研究了氧化钛加入量(质量分数为1%～5%)对Cr_2O_3材料烧结特性的影响.结果表明:TiO_2能显著促进Cr_2O_3材料的烧结,随着TiO_2加入量的增加,样品的体积密度迅速增加,显气孔率迅速下降;加入3%TiO_2基本能全部固溶到Cr_2O_3晶粒内,形成固溶体;当TiO_2的加入量超过3%时,富余部分形成钛铬化合物Cr_2Ti_(n-2)O_(2n-1)(3相似文献   

Differences in Wetting Characteristics of Bi2O3 Polymorphs in ZnO Varistor Materials

Detailed analysis of the microstructure of grain boundaries, especially triple-grain and multiple-grain junctions, in ZnO varistor materials has been performed using transmission electron microscopy. Different polymorphs of Bi₂O₃ are shown to exhibit different wetting properties on ZnO interfaces. Recent investigations suggest that the equilibrium configuration consists of crystalline Bi₂O₃ in the triple-grain and multiple-grain junctions and an amorphous bismuth-rich film in the ZnO/ZnO grain boundaries. The present investigation supports this suggestion for δ-Bi₂O₃ and also adds to the microstructural image and wetting properties of α-Bi₂O₃.     

Effect of Additives on the Hydration Resistance of Materials Synthesized from the Magnesia–Calcia System

The effect of a variety of doping additives on the hydration resistance of calcined materials in the MgO–CaO system was investigated. Samples were prepared from lightly calcined flotation magnesite that was mixed with dolomite, as well as from analytically pure CaO and MgO; then, the samples were doped with additives that contained cations with various valences (monvalent to tetravalent). Both the hydration rate and the powdering rate were measured. The important role of the higher-valence cations in improving the hydration resistance of the MgO–CaO materials was revealed. This behavior is believed to be due to the formation of vacancies in solid solutions of CaO or MgO with higher-valence cations. The Ti⁴⁺ cation forms a solid solution with CaO, which reduces the Ca²⁺ concentration and leads to the improved hydration resistance of calcined materials from the MgO–CaO system.