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.     

聚苯胺/金属氧化物复合导电薄膜的性能

采用溶胶－凝胶法制备出聚苯胺／金属氧化物复合导电薄膜，通过添加TiO2,Ai2O3等金属氧化物粒子可改善导电薄膜材料的电导率和热稳定性，对于不加入金属氧化物粒子的薄膜材料热处理温度在80℃以上将使其导电性降低，而对于加入TiO20.15g的试样其80℃热处理后的电导率则上升至1000S／m.     

SiO_2-ZrO_2复合膜的制备及其工艺参数的研究

采用溶胶-凝胶法制备SiO2-ZrO2复合薄膜,研究溶胶成分和烧结工艺对薄膜开裂及其性能的影响.采用乌氏黏度计、热重分析仪(TG-DTG)、X射线衍射分析仪(XRD)和原子力显微镜(AFM)对薄膜进行表征.结果显示,溶胶的组成、特定温度的升温速率对薄膜的开裂起决定性作用;当摩尔比为n(SiO2)∶n(ZrO2)=2.0∶0.5时,制得溶胶黏度适中、透明稳定,干燥的凝胶在0.5℃/min的升温速率下升至600℃焙烧2h,并在75、190和230℃附近缓慢升温且适当保温后,可得无裂缝且均匀、透明的SiO2-ZrO2复合薄膜,所制备的薄膜具有较大的比表面积和较窄的孔径分布.     

纳米ZrO2薄膜的制备与表征

用水热盐溶液水解法可合成含有单斜相晶态纳米ZrO2颗粒的ZrO2溶胶体.用匀胶法制备的纳米ZrO2薄膜厚度约160 nm,折光率为1.56.纳米ZrO2薄膜表面质量良好,无表面裂隙,台阶仪研究表明薄膜表面粗糙度算术差Ra=2.7 nm,均方根差Rq=3.7 nm.以ZrO2为高折射率膜层,碱催化的溶胶凝胶SiO2为低折射率膜层,制备了SiO2/ZrO2多层高反射率薄膜,10周期的SiO2/ZrO2多层膜系,在1.06 μm波段处透过率为1%,薄膜表面抗激光损伤阈值约15 J/cm2(1.06 μm,2.5 ns高功率激光作用下).     

脉冲激光沉积ZrW_2O_8/ZrO_2复合薄膜及其靶材制备

采用化学共沉淀法合成26wt%ZrW_2O_8/ZrO_2近零膨胀复合陶瓷靶材,并以脉冲激光法在石英基片上沉积制备了ZrW_2O_8/ZrO_2复合薄膜.利用X射线衍射仪(XRD)、热膨胀仪、扫描电子显微镜(SEM)研究了复合靶材的晶体结构、热膨胀性能和致密度,同时也探索了热处理温度对复合薄膜的相组成和表面形貌的影响.结果表明:合成的靶材由α-ZrW_2O_8和m-ZrO_2组成,26wt%ZrW_2O_8/ZrO_2复合靶材在30℃～600℃的热膨胀系数为-0.5649×10~(-6)K~(-1),近似为零,且靶材致密、均匀;脉冲激光沉积制备的薄膜为非晶态,表面平滑、致密,随着热处理温度的升高,薄膜开始结晶,在1200℃热处理6min后得到纯ZrW_2O_8/ZrO_2复合薄膜,且两相物质在膜层中分散均匀,结晶后的薄膜存在一些孔洞缺陷.     

类金刚石薄膜的激光损伤特性及工艺优化

采用脉冲真空电弧沉积(PVAD)技术制备了类金刚石(DLC)薄膜,并对其抗激光损伤特性进行了研究,优化了制备工艺.对DLC薄膜激光损伤阈值(LIDT)的测试结果表明,随着厚度的增加,薄膜的LIDT开始呈下降趋势,当厚度达到100nm以上时,则趋于一个稳定值.正交实验结果的处理和分析表明,在所给定的工艺参数范围内,主回路电压是影响DLC膜抗激光损伤性能的最主要因素,基片温度、清洗时间和脉冲频率则影响较小.为得到较好的抗激光损伤能力,采用PVAD技术制备DLC薄膜的最佳工艺参数为:清洗时间20 min、基片温度150℃、脉冲频率5 Hz、主回路电压150 V.退火处理会使DLC薄膜的激光损伤阈值明显提高.     

电子束蒸发法制备TiO2薄膜的折射率研究

用电子束蒸发法制备TiO2薄膜,并对其进行300℃、400℃、850℃热处理和掺杂.详细研究了工艺参数、热处理和掺杂对TiO2薄膜折射率的影响.实验结果表明:镀制高折射率的氧化钛薄膜最佳工艺参数为基片温度200℃、真空度2×10-2 Pa、沉积速率0.2 nm/s;随着热处理温度的升高,薄膜折射率也逐渐增大;适量掺杂CeO2(CeO2:Ti0质量比1.7:12)会提高薄膜的折射率,过量掺杂CeO2反而会降低折射率.     

Al2O3-SiO2复合膜的疏水改性及表征

采用溶胶-凝胶法制备Al2O3-SiO2复合薄膜,通过添加二甲基二乙氧基硅烷(DDS)对其进行疏水改性。研究了DDS添加量对复合溶胶体系稳定性和复合膜表面疏水性的影响,采用接触角测量、红外光谱(IR)、热重分析(TG-DTG)、原子力显微镜(AMF)对样品进行表征。结果表明,对于Al2O3∶SiO2(mol/mol)=1∶2比例下制得的复合膜,随着DDS的加入,薄膜表面疏水性明显增强,当DDS加入过多时,会影响复合溶胶的稳定性,实验确定DDS加入量的最佳值为1%(体积分数);DDS的加入没有破坏复合膜的网格结构,复合膜仍以SiO2颗粒为骨架;经200℃热处理后,可得到具有良好的疏水性能的复合膜。     

不同靶材制备ZrW_2O_8薄膜的对比研究

分别采用摩尔比n(WO3):n(ZrO2)=2.8:1复合陶瓷靶材、纯ZrW208陶瓷靶材以及WO3和ZrO2双靶,以射频磁控溅射法在石英基片上沉积制备ZrW2O8薄膜.利用x射线衍射仪(XRD)、扫描电子显微镜(SEM)研究了退火温度对采用不同靶材沉积制备薄膜的相组成和表面形貌的影响;用划痕仪、表面粗糙轮廓仪测量薄膜与基片之间的结合力和薄膜厚度.试验结果表明:采用不同靶材磁控溅射制备的薄膜均为非晶态,经过不同温度退火后,不同靶材制备的薄膜的相组成和表面形貌有所不同,但在高温1200℃热处理3 min后均得到立方相ZrW2O8薄膜,其中采用WO3和ZrO2双靶交替磁控溅射制备的立方相ZrW2O8薄膜纯度最高,致密度好,且薄膜与基片之间结合力良好.     

热处理对TiO2薄膜制备及亲水性的影响

采用廉价的TiCl_4为前驱体水解合成TiO_2水溶胶,利用辊涂装置镀膜并通过热处理制得了一系列TiO_2薄膜。运用X射线粉末衍射(XRD)、扫描电镜(SEM)、紫外-可见光谱(UV-Vis)、光致发光谱(PL)对TiO_2薄膜进行了表征,并采用接触角测量仪考察了热处理温度、避光保存时间、UV光照时间对各薄膜亲水性的影响。结果表明,制得的薄膜不影响玻璃基材的可见光透过率;通过热处理,能有效增强薄膜对可见光的吸收能力,显著抑制光生电子和空穴的复合;当热处理温度为450℃时,TiO_2薄膜表现出了最好的亲水性,其薄膜与水的接触角达到0°。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.