极限电流氧传感器中Pt／ZrO2电极的极化

用“三电极”法测试了Ｐｔ／ＺｒＯ２电极在４００－６００℃温度范围内分别充作阴、阳极时的极化规律。用数学处理将该电极的极化分离为电化学极化和欧姆极化两部分，讨论了气氛、工作电流、温度对它们的影响。得出该电极适用于高工作温度、低工作电流情形。指出设计使用于低温、高氧分压下的极限电流氧传感器，如选用Ｐｔ／ＺｒＯ２电极应特别注意扩散障的结构，否则应选用活性更高的电极组合。     

Effects of Homo-buffer Layer on Properties of Sputter-deposited ZnO Films

Two-step growth regimes were applied to realize a homoepitaxial growth of ZnO films on freestanding diamond substrates by radio-frequency(RF)reactive magnetron sputtering method.ZnO buer layers were deposited on freestanding diamond substrates at a low sputtering power of 50 W,and then ZnO main layers were prepared on this buffer layer at a high sputtering power of 150 W.For comparison,a sample was also deposited directly on freestanding diamond substrate at a power of 150 W.The effects of ZnO buffer layers...     

Pt/MoO3/ZrO2催化剂的制备及三效催化性能的研究

采用浸渍法制备了MoOz/ZrO2,用低温氮吸附-脱附法和NH3-程序升温脱附法(TPD)分别对其比表面积和酸碱性进行了表征.结果表明,MoO3/ZrO2具有106.8m2/g的比表面积和超强酸的性能.用等体积浸渍法制备了Pt/MoO3/ZrO2催化剂,在汽车尾气模拟气中考察了其对C3H8、CO和NO的催化活性.与传统三效催化剂Pt/La2O3/Al2O3相比较,Pt/MoO3/ZrO2具有更好的低温起燃性能和更宽的空燃比窗口,并显著地改善了C3H8在富氧状态下的转化效率.通过XRD、H2-TPR对催化剂进行了表征,结果表明,Pt在催化剂载体上具有高度的分散性和优异的氧化还原性能.     

ZrO2薄膜的XPS分析

用射频溅射制备了氧化锆薄膜，用Ｘ光电子能谱技术分析了ＹＳＺ膜的结构，发现低能轰击会引起膜中钇的反优再溅射，造成钇的分布不均匀导致单斜相的出现。     

正偏压作用下多弧离子镀ZrO2薄膜的组织结构与力学性能研究

在氧气和氩气的混合气体中,以O2/Ar流量比固定为1/4的条件,通过改变正偏压大小,采用多弧离子镀方法制备了新型高k栅介质——ZrO2薄膜。通过X射线衍射(XRD)和原子力显微镜(AFM)研究了在不同正偏压作用下正偏压值与薄膜的相结构、表面形貌之间的关系,利用纳米压痕仪测量了不同正偏压作用下沉积得到的ZrO2薄膜的硬度及弹性模量,并观察了ZrO2薄膜经不同温度退火处理后的相结构及表面形貌的变化。结果表明,在各个正偏压条件下,薄膜结构呈微晶或非晶;ZrO2薄膜的均方根粗糙度随着正偏压的升高而降低;正偏压为100V时硬度和弹性模量均达到最大值,分别为16.1GPa和210GPa。     

ZrO2:CdS薄膜的光物理性质

利用吸收和荧光光谱研究了ＺｒＯ_２：ＣｄＳ薄膜的光物理特性．实验观察到了随颗粒尺寸的减小ＣｄＳ的吸收带边的蓝移现象．研究了不同激发条件下的荧光光谱,发现了薄膜中ＣｄＳ的微弱的荧光发射．并且分析了介质效应对ＣｄＳ光学特性的影响．     

Compositional, structural and electronic characteristics of HfO2 and HfSiO dielectrics prepared by radio frequency magnetron sputtering

HfO₂ and HfSiO films were prepared on Si substrates by using radio frequency magnetron sputtering (RFMS). Compositional, structural and electronic properties of the two films were investigated completely. X-ray photoelectron spectroscopy (XPS) spectra showed that the atom ratio of Hf to O was about 1:2 in the HfO₂ film and the chemical composition of the HfSiO film was Hf₃₇Si₇O₅₆. Grazing incidence X-ray diffraction (GI-XRD) patterns indicated crystallization in the HfO₂ film after 400 °C annealing, but there is no detectable crystallization in the HfSiO film after 800 °C annealing. C-V measurements indicated that the dielectric constants for the HfO₂ and HfSiO film were 20.3 and 17.3, respectively. The fixed charge densities were found to be 6.0 × 10¹² cm⁻² for the HfO₂ film and 3.7 × 10¹² cm⁻² for the HfSiO film. I-V characteristics showed that the average leakage current densities were 2.4 μA/cm² for the HfO₂ film and 0.2 μA/cm² for the HfSiO film at the gate bias of 1 V.     

磁控溅射MoS2/WS2复合薄膜的工艺与摩擦学性能研究

采用MoS2/WS2复合靶材在不锈钢和硅基片上溅射MoS2/WS2纳米薄膜,通过多次实验,得到溅射MoS2/WS2薄膜的最佳工艺如下:溅射气压4.0Pa,靶基距为70mm,溅射功率为150W,溅射时间为3h.使用X-射线衍射仪,能谱仪,扫描电子显微镜对薄膜的成分和结构进行分析.采用HH-3000薄膜结合强度划痕试验仪,纳米压痕测试系统,UNT-3摩擦磨损试验机对薄膜进行机械性能和摩擦磨损性能分析,结果表明:在大气环境中,WS2/MoS2 复合薄膜摩擦性能要优于纯MoS2薄膜.     

硒化方式对CuInSe2薄膜结构、成分和形貌的影响

采用直流磁控溅射技术,首先在玻璃衬底上制备Mo薄膜,然后制备CuIn预制层。以固态硒粉为硒源,采用硒薄膜法和硒蒸气法两种硒化工艺,经过三步升温硒化方式对CuIn预制膜进行硒化制备CuInSe2薄膜。通过X射线衍射、能量散射谱和扫描电镜测试分析手段,分析CuIn预制膜和每一步硒化热处理后薄膜结构和形貌的变化。结果表明:两种方法硒化后均形成具有单一黄铜矿相结构的CuInSe2薄膜,薄膜具有(112)面择优取向,硒蒸气法形成的晶粒较大,但均匀性差。     

NiO/Ag/NiO透明导电膜光电特性研究

在室温条件下, 利用磁控溅射法在玻璃衬底上制备了NiO/Ag/NiO透明导电膜, 研究了不同NiO层和Ag层厚度对三层膜可见光透过率和电阻特性的影响。结果分析表明:制备的NiO/Ag/NiO为N型透明导电膜。在400~800 nm的可见光区域内, 随着NiO和Ag层厚度的增加, 薄膜的透光率先增大后减小。NiO层厚度为30 nm且Ag层厚度为11 nm时, 叠层膜具有较好的光学特性, 其最大透过率为84%, 薄膜电阻为3.8Ω/sq, 载流子浓度为7.476×10²¹cm^-3。对薄膜透过率进行了计算机模拟, 发现结果与实验中大致趋势相同, 但因为折射率选择和薄膜界面等因素的影响, 在可见光区域后半段实验值大于计算值。     

等离子沉积氧化锆涂层显微组织及性能研究

目的以氧化锆粉末作为喷涂材料,使用等离子喷涂的方式制备出性能优异的氧化锆涂层。方法通过不同的工艺参数来对涂层的显微组织及性能进行优化,分别利用扫描电镜(SEM)、X射线衍射分析仪(XRD)等方法,研究了工艺参数对涂层显微组织影响,并通过高温氧化测试来研究涂层的抗高温性能。结果在其他喷涂条件固定的情况下,涂层的厚度与喷涂时送粉量有关,送粉量越高则涂层厚度越大;当改变喷涂距离时,涂层的致密度则随着喷涂距离的增加而降低;在高温氧化40h后,涂层表面没有发生明显变化。结论通过等离子喷涂制备的氧化锆涂层具有较好的致密度,孔隙率最低仅为3.24%;涂层具有良好的热稳定性,能够长时间在高温下稳定使用。     

DC magnetron sputtering of Si to form SiO2 in low-energy ion beam

Silicon dioxide (SiO₂) films were deposited by magnetron sputtering and ion-beam oxidation (IBO) in separate zones at ambient temperature. The optical and structural characteristics of the films were analyzed by spectrophotometry, Fourier transform infrared absorption spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscope. The oxygen ratio in the ion beam and the energy of ion bombardment during deposition has strong influence on the optical and physical properties of SiO₂ films. The experimental results indicated that the IBO method could finely manipulate the structure and properties of the growing films.     

ZrO2-膨化石墨/焦炭复合材料的结构和制备

运用两种不同技法制备了ZrO2纳米粒子改性的膨化石墨/焦炭复合材料,应用XRD、SEM和TEM对所得ZrO2改性炭材料进行了表征.技法1:在ZrO(NO3)2及NH4OH溶液中反复交替地浸渍低密度膨化石墨/焦炭块体,随后在1200℃氮氛中热处理,以使在炭块自由表面沉积ZrO2纳米粒子的薄层.技法2:将可膨胀石墨、酚醛树脂粉和ZrOC2 O4-改性的纤维素纤维混合物封装于一容器中,使之经受900℃热激震,随后在氮氛中1200℃热处理,获得改性复合材料.结果表明:复合材料中ZrO2纳米粒子呈现三种尺寸:6nm～30nm为单独的纳米粒子和小微粒;200nm～1000nm为长树突状结构物;1μm～40μm为形如纤维素前驱体的杆状物.     

氧化锆增韧HA/ZrO2功能梯度涂层的TEM分析

利用净能量控制的PRAXAIR4500型等离子喷涂系统,在钛合金基体上制备出HA/ZrO2功能梯度涂层,采用HTEM、XRD、SEM等对涂层过渡层ZrO2相的结构特征进行分析.结果表明:(1)富锆的过渡层存在ZrO2 3种晶型,主要以四方氧化锆为主,含有少量的立方氧化锆及微量的单斜氧化锆和CaZrO3,单斜氧化锆的出现说明材料内发生了四方氧化锆向单斜氧化锆马氏体相变,这种马氏体相变有利于提高HA材料的韧性;(2)生物活性功能涂层的富锆过渡层致密,与钛合金基体结合紧密,纯羟基磷灰石的表面层具有典型的多孔结构特征,整个涂层沿垂直基体方向从过渡层致密结构向表面层多孔结构过渡;涂层的这种结构特征有利于改善功能梯度涂层的综合性能,提高涂层与基体的结合强度,其结合强度达到48.6MPa.     

Pressureless sintering and characterization of cordierite/ZrO2 composites

Cordierite/ZrO₂ composites with 5 to 25 wt% ZrO₂ were fabricated by conventional powder mixing and pressureless sintering method. Their densification behavior, microstructure, mechanical and thermal properties were studied. By dispersing 25 wt% (9.57 vol%) ZrO₂, densified cordierite/ZrO₂ composite with a relative density of 98.5% was obtained at an optimum sintering condition of 1440 °C and 2 h. ZrO₂ particles were homogenously dispersed within matrix grains and at the grain boundaries. The intragranular particles were finer than 100 nm and the intergranular particles were coarser. Both fracture strength and toughness could be enhanced more than two times higher, compare to those of monolithic cordierite, by dispersing 25 wt% ZrO₂ into the cordierite matrix. The toughening mechanism in the present composites was mainly attributed to martensitic transformation due to ZrO₂ dispersion. Electronic Publication     

ZrN/W2N纳米多层膜的调制比对其性能的影响

利用射频磁控溅射系统制备了调制周期为30 nm的具有不同调制比例的ZrN/W2N纳米多层膜。研究表明:ZrN/W2N纳米多层膜的界面清晰,通过把ZrN周期性地插入到W2N层,多层薄膜的整体应力得到缓解。在调制比tZrN∶tW2N=2∶3时,纳米多层膜的应力值最小。多层膜的硬度和弹性模量基本高于ZrN和W2N单层材料的平均值,随着调制比的减小,它们的值均有上升趋势,并在tZrN∶tW2N=2∶3时分别达到最高值34 GPa和424 GPa,同时多层膜的膜基结合强度也达到最佳效果,其临界载荷超过了100 mN。多层膜的机械性能改善明显与其调制层结构和多晶结构有着直接的联系。     

ZrO2薄膜的力学性能和摩擦学性能研究

在单晶硅表面成功地获得了自组装单层薄膜(MPTS-SAM),并将薄膜表面的巯基(-SH)完全氧化成磺酸基(-SO3H),从而获得了磺酸化的MPTS-SAM.采用静电自组装技术成功使ZrO2纳米微粒组装到磺酸化的MPTS-SAM表面获得淀积ZrO2薄膜.将ZrO2薄膜分别在500℃和800℃进行热处理后,ZrO2薄膜的厚度逐渐减小,这可能是随着温度的升高薄膜的表面密度逐渐增大所致.对ZrO2薄膜的力学和抗划伤性能分析发现:随着温度的升高,ZrO2薄膜的硬度和弹性模量依次增加,同时薄膜的抗划伤性能也逐渐提高.摩擦磨损实验表明:利用该方法制备的ZrO2薄膜经800℃烧结处理后适于在低负荷、低滑动速度下作为减摩、抗磨保护性涂层.     

喷雾造粒ZrO2粉料坯体性能的研究

以喷雾造粒 ＺｒＯ_２粉料为研究对象,通过对粉料的压力－密度曲线及坯体的 ＳＥＭ显微结构分析,发现喷雾造粒粉料的粒度分布对坯体密度的影响较小;颗粒强度的大小是获得均匀的坯体结构的关键,颗粒的强度与其大小及环境湿度有关,因此颗粒适当的增塑及去除大颗粒均有利于坯体显微结构的改善．     

Thermodynamic Assessment of the ZrO2—CeO2 and ZrO2—CeO1.5 Binary System

An optimal set of thermodynamic parameters of the ZrO2-CeO1.5 system has been obtained using phase diagram data by modern CALPHAD (CAL culation of PHAse Diagrams) technique.The liquid and other solid solution phases were regarded as substitutional solution.The ordered ZrCe2O7 phase was treated as a stoichiometric compound.The ZrO2-CeO2 system has been re-optimized with new reference state.A comparison between the ZrO2-CeO2 system and ZrO2-CeO1.5 system has been made through calculation.With the calculation, the experimental information is well reproduced and a good agreement is obtained.