宽谱增透双层TiO2-SiO2/SiO2薄膜的制备与性能

采用溶胶-凝胶法制备了双层TiO_2-SiO_2/SiO_2薄膜,调控了底层薄膜的折射率及双层薄膜不同的厚度匹配,研究了在不同厚度匹配下薄膜的光学性能。通过场发射扫描电子显微镜、椭偏仪、紫外-可见-红外分光光度计研究了薄膜的微观结构、厚度、折射率和光学透过率。研究表明:以TiO_2与SiO_2混合溶胶镀膜获得了折射率可调(1.5～2.0)的薄膜,在TiO_2-SiO_2层与SiO_2层的厚度分别约为160 nm、90 nm时获得了光学性能较优的薄膜,薄膜在光学宽谱380～1 100 nm范围内表现出明显的增透效果,可见光最高透过率可达97.5%,宽谱平均透过率为93.9%。     

非λ/4激光增透膜的试制

我厂研制的激光平车仪对光学零件提出了表面剩余反射率不大于0.2%的要求。 镀于K9玻璃上的单层氟化镁(MgF2)增透膜只能把剩余反射率从4.2%下降到1.6%,满足不了平车仪的要求。为此,我们采用了硫化锌(ZnS)和氟化镁(MgF2)组成的非λ/4双层增透膜。由于较好地解决了ZnS层厚度控制问题,使得镀于 K9玻璃上的双层增透膜都达到了使用要求。K9玻璃表面剩余反射率从4.2%下降到0.1%～0.2%(在中心波长处)。 膜系选择 根据光线垂直入射时膜系的反射率公式 可知,当y=n0时可以消反射B=0 式中n0是空气的折射率等于1 y是膜系的等效导纳。在玻璃的折射率n…     

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。     

制备工艺参数对TiNx/Ag/TiNx低辐射膜性能的影响

采用射频磁控溅射法在玻璃基片上沉积了TiNx/Ag/TiNx低辐射膜,研究了制备工艺参数对低辐射膜光学性能的影响以及低辐射膜的耐腐蚀性能.结果表明,TiNx薄膜可对膜系起到很好的保护作用,当膜系的TiNx保护层厚度为32nm、内层TiNx膜厚为16nm(氮气流量为55sccm)、Ag层厚度为16nm时,制备的低辐射膜系具有优良的透过率、低辐射性能和耐腐蚀性能.     

具有超亲水光催化性能的λ/4-λ/2型两层宽频增透膜的制备和性能研究

以多孔SiO₂/TiO₂复合膜为膜层材料, 采用溶胶-凝胶法制备得到λ/4-λ/2型无峰两层宽频增透膜, 此工艺制备过程简, 单且对膜层折射率要求较低, 镀制两层膜的K9基片在500~700 nm波段维持较高的透过率, 在此区间透过率平均值为99.4%, 在可见光区400~800 nm的平均透过率为99.0%。两层膜表现出优异的超亲水性能, 在无需紫外光照的条件下, 其在0.5 s的水接触角仅为2.2°, 且超亲水性能能够维持超过20 d。同时, 两层膜表现出一定的光催化降解有机污染物的能力。     

蓝宝石衬底上增透膜的设计与制备

采用彻底搜索法,在蓝宝石(α-Al2O3)衬底上分别设计出了SiO2单层和SiO2／Si双层增透保护膜系。设计结果表明单层及多层增透膜系均可实现蓝宝石中红外波段(3～5μm)的增透。利用射频磁控反应溅射法制备出所设计的增透膜系。结果表明,蓝宝石衬底上镀单层及多层增透膜系后红外透过率明显提高;当蓝宝石衬底双面镀SiO2膜后．在3～5μm波段范围内,平均透过率达到96．43％．比未镀膜时的平均透过率87．01％提高了9,42％．满足了设计使用要求。     

多功能单层二氧化硅增透膜的设计与制备

通过膜层设计软件(TFCalcTM)设计了在400~1 100nm波长范围内具有高透过率的单层增透膜。以正硅酸乙酯(TEOS)和甲基三乙氧基硅烷(MTES)为共混前驱体、盐酸为催化剂、十六烷基三甲基溴化铵(CTAB)为模板剂制得甲基修饰的二氧化硅溶胶,通过浸渍提拉法结合溶剂挥发自组装技术成功制备了所设计的多功能单层增透膜。结果表明,(1)增透膜在650nm的最大透过率可达到99.9%,在400~1 100 nm波长范围内的光伏透过率(TPV)高达98.7%,与软件设计结果一致;(2)TEOS与MTES共聚后,显著提高增透膜的疏水性,其对水的接触角从24°提高至85°;(3)单层二氧化硅增透膜具有较好的耐磨擦性。这种兼具高透过率、耐磨擦性和一定疏水性的多功能增透膜在太阳能电池领域具有应用价值。     

溅射气压对HfO_2薄膜结构和光学性能的影响

HfO2薄膜的结构和光学性能与反应溅射时使用的气压有很强的依赖关系。薄膜的晶粒生长取向、生长速率和折射率明显受溅射气压的影响。所有的薄膜均为单斜相,晶粒尺寸在纳米量级。薄膜的折射率在1.92～2.08范围内变化,透过率大于85%。结果表明,这些HfO2薄膜很适宜用作增透膜或者高反膜。此外,通过Tauc公式推出光学带隙在5.150～5.433eV范围内变化,表明样品是良好的绝缘体。     

基于透反射光谱确定Te/TeO_2-SiO_2复合薄膜的光学常数

基于电化学诱导sol-gel方法制备Te/TeO_2-SiO_2复合薄膜的紫外-近红外投射光谱实验,采用透反射光谱测量法推导出Te/TeO_2-SiO_2复合薄膜在200~1100nm波长范围内的光学常数,包括光学透过率、反射率、线性吸收系数、消光系数、线性折射率及禁带宽度。研究发现,复合薄膜具有高折射率(1.93~2.03),测试波长为1064nm,低吸收和禁带宽度宽(3.07~3.40eV)等光学特性,同时薄膜的光学常数对制备过程中的重要参数制备电压表现出强烈的依赖性,制备电压越大薄膜的光学透过率降低,薄膜厚度增大,线性折射率增大。     

低折射率疏水SiO_2薄膜的制备和表征

为了制备低折射率疏水SiO_2薄膜,将正硅酸乙酯(TEOS)和二甲基二乙氧基硅烷(DDS)在碱性条件下共水解缩聚,再以六甲基二氮硅烷(HMDS)做进一步的改性,采用提拉浸渍工艺在玻璃基底上制备单层增透膜。通过对溶胶粘度随老化时间的变化规律及HMDS添加对薄膜接触角影响等的分析与研究,制备了接触角最大的低折射率薄膜;同时对薄膜的红外特性、透过率、折射率进行了表征。结果表明:TEOS和DDS共水解缩聚提高了膜层疏水性,经HMDS改性后,薄膜的接触角为149°,折射率为1.12。     

Steam-side scale morphologies associated with scale exfoliation from ferritic steel T22

Abstract

Observations of steam-formed scales on type T22 ferritic steel reheater tubes have provided some insights into the scale morphologies associated with exfoliation. Measurements indicated that as the total thickness of the adherent scales increased, the ratio of the thicknesses of the main inner (Fe–Cr spinel) and outer (magnetite) layers increased continuously to a maximum of approximately 2.5. The often-assumed thickness ratio of 1.0 did not persist after a laminated structure of pairs of spinel and magnetite layers was developed in the main inner layer. The development of such multi-laminations appeared to be associated with a decrease in the rate of growth of the main outer, magnetite layer. In this particular set of samples, exfoliation occurred in scales of total thickness greater than approximately 270 μm, and involved separation of a single pair of oxide layers of similar thickness that consisted of the original outer magnetite layer and part of the original spinel layer. The scale lost in subsequent exfoliation events at essentially the same site consisted of a further pair of layers comprising the new magnetite layer re-grown after the initial event, and a further part of the original spinel layer. Exfoliation events did not appear to involve the whole of the spinel layer existing at that time, only the equiaxed region immediately subjacent to the magnetite and a portion of the laminated structure.     

C/C复合材料表面水热电泳沉积SiCn/SiC复合抗氧化涂层研究

采用水热电泳沉积法在SiC-C/C复合材料表面制备纳米碳化硅（SiC_n）涂层. 采用XRD和SEM对涂层的晶相组成、表面和断面的微观结构进行了表征. 主要研究了水热沉积温度对涂层的结构及高温抗氧化性能的影响, 并分析了涂层试样在1600℃的高温氧化气氛下失效行为. 结果表明：纳米碳化硅涂层主要由β-SiC组成. 涂层的致密程度和厚度随着水热沉积温度的升高而提高. 随着水热温度的提高, 涂层试样的抗氧化性能也有明显的提高. 在120℃水热沉积温度下制备的涂层试样可在空气气氛1500℃下有效保护C/C复合材料202h,而氧化失重仅为2.16×10^-3g/cm². 在1600℃下氧化64h后失重为3.7×10^-3g/cm². 其高温失效是由于长时间的氧化挥发后表面SiO2膜不能完全封填表面缺陷, 内涂层中产生了贯穿性的孔隙所致.     

Biomimetic whisker-shaped apatite coating of titanium powder

Biomimetic apatite coatings on chemically modified titanium powder have been processed and the resulting coating layers evaluated in terms of morphology, composition and structure, using TF-XRD, XPS, SEM, TEM and FTIR analysis. After 7 days immersion in a simulated body fluid (SBF), nanometer-sized fine precipitates with an amorphous whisker-like phase and a Ca/P atomic ratio of 1.94 were obtained on the external surface of the titanium particles. When the immersion time in SBF was extended to 16 days, the coating layer consisted of the whisker-like nanostructured crystals of carbonated hydroxyapatite with a atomic ratio of 3; in such a case, a double coating layer was developed. The double layer could be divided into two regions and could be clearly distinguished: an inner dense region (~200 nm in thickness) which may include hard agglomerated crystals and an outer less dense region (> 500 nm in thickness) in which crystals are loosely distributed.     

用脉冲喷射电沉积法制备纳米晶镍镀层

采用脉冲喷射电沉积方法制备了纳米晶镍镀层,用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X射线衍射(XRD)等方法研究了镀层的生长形貌和微观结构,并考察了脉冲电流密度对镀层微观结构如晶粒尺寸、织构等的影响.结果表明:镀层内表面(基体一侧)具有比外表面(镀液一侧)更为精细的晶粒结构,说明随着厚度的增加,镀层中的晶粒逐渐粗化.随着电流密度从45 A/dm2增加到180 A/dm2,镀层中晶粒生长的择优取向由(111)织构逐渐转变为强(220)织构.当电流密度从45 A/dm2增加到120 A/dm2时,镀层平均晶粒尺寸逐渐减小;而进一步增加电流密度到180 A/dm2,镀层晶粒尺寸又会有轻微的增大.     

ZM6铸造镁合金微弧氧化膜层性能研究

针对ZM6铸造镁合金,为获得综合性能优异的陶瓷膜层,在硅酸钠和氢氧化钠的碱性溶液中,用双向脉冲电源进行微弧氧化处理。采用环境扫描电镜(SEM)、X射线衍射(XRD)研究陶瓷膜层微观形貌及组成,采用拉伸法、中性盐雾试验、轴向加载疲劳试验等方法研究附着力、耐蚀性及疲劳性能等。结果表明:陶瓷膜层大致由表层疏松层、中间致密层以及内部过渡层组成,表层疏松多孔,过渡层与基体紧密结合。陶瓷层与基体结合好,附着力大于50MPa;微弧氧化处理后,大幅度提高合金耐腐蚀性能,中性盐雾大于336h;陶瓷膜层使基体疲劳性能降低18%。     

TC4钛合金微弧氧化因素对生物陶瓷膜中Ca,P相对含量的影响

为了提高钛合金陶瓷膜的生物相容性,采用微弧氧化技术在TC4钛合金表面制备了一层富含Ca,P的生物活性陶瓷膜。采用SEM,EDS,XRD研究了电流密度、溶液中Ca,P摩尔比、添加剂EDTA.2Na浓度对膜层中Ca,P相对含量(原子分数)及Ca,P摩尔比的影响及微弧氧化生物陶瓷膜层的形貌及组成。结果表明:随着电流密度的增大,膜层中的Ca,P相对含量增加,Ca,P摩尔比也逐渐增加;增大溶液中Ca,P摩尔比,膜层中Ca相对含量有所增加,Ca,P摩尔比也逐渐增加;当加入添加剂EDTA.2Na时,膜层中的Ca相对含量显著增加,从而使膜层中Ca,P摩尔比显著增加;氧化膜由致密的内膜层和多孔的外膜层构成,主要由Ca,P,O,Ti,V元素组成,其相成分主要为金红石和板钛矿型TiO2,并含有一定量的非晶相Ca,P化合物。     

铝合金表面等离子体电解氧化陶瓷涂层在NaCl溶液中的电化学阻抗谱研究

通过调整电解液中硅酸钠的浓度, 利用等离子体电解氧化(PEO)技术在铝合金LY12表面制备了各种陶瓷涂层, 利用光学显微镜、XRD、电化学阻抗谱(EIS)对涂层的形貌、成分和涂层在NaCl溶液中耐腐蚀性能进行了研究. 结果表明: 提高电解液中硅酸钠的浓度可以使得涂层的总厚度增加, 但过高或过低的浓度都会导致致密层厚度的减薄. 当浓度为20g/L时, 所制备的涂层的成分以氧化铝为主; 当浓度为40g/L时, 涂层的成分主要是莫来石和氧化铝; 当浓度超过60g/L 时, 涂层的成分主要为非晶相. EIS的研究表明, 涂层耐腐蚀性取决于涂层中的致密层, 增加致密层的厚度可以提高PEO涂层的耐腐蚀性, 在中性、酸性、碱性腐蚀介质中, PEO涂层都显示出对基体良好的保护作用.     

Effect of Nickel Pre-Plated on Microstructure and Oxidation Behavior of Aluminized AISI 316 Stainless Steel

Aluminizing of nickel pre-plated AISI 316 is prepared by a high-activity pack at 1050 °C. The effect of initial nickel layer with different thicknesses on microstructure and oxidation behavior of coating is investigated. After aluminization, the surface microstructure of stainless steel mainly consists of β-(Fe, Ni)Al as matrix with β-FeAl + α -(Fe, Cr) precipitates and an inter-diffusion layer with γ phase. Aluminized coating on specimens with 10 and 20 µm primary thicknesses of the nickel layer includes three layers. The outer zone is made up of β-NiAl thin layer and a β-(Fe, Ni)Al layer. As the nickel layer increases to 50 and 100 µm, aluminide layers consist of outer and inner zone with β-NiAl and Ni₃Al phase, respectively. Oxidation tests at 950 °C show that the oxidation resistance of aluminide coatings improves and oxidation kinetics follows a sub-parabolic rate law by increase in thickness of initial nickel layer.     

一类非均布荷载作用下双层厚壁圆筒光滑接触时的应力解析解

采用复变函数方法,给出了双层厚壁圆筒外壁受有一类两向不等压非均布径向压力,内壁受有均布压力作用时平面问题的应力求解方法。在两层圆筒光滑接触的假定下,获得双层厚壁圆筒的应力解析解。通过算例分析了不同弹性模量组合时圆筒内不同截面的切向应力与径向应力分布规律,研究结果表明:当内壁均布压力较小时,两层圆筒的内壁处切向应力沿环向均呈余弦分布,且都在内壁的最小地应力方向承受最大压应力,在最大地应力方向承受最大拉应力;径向应力沿径向在圆筒0#x000b0;、45#x000b0;、90#x000b0;截面处分别呈近似#x0201c;M#x0201d;状、#x0201c;菱形#x0201d;、#x0201c;W#x0201d;状分布;随着内外层弹性模量比值的增大,内层圆筒内壁附近切向应力增大,径向应力在最小地应力方向增大,在最大地应力方向减小,而在外层筒分布规律相反。采用内软外硬的弹性模量组合,能有效的减小圆筒内层内壁处的应力集中程度。     

Optimum design method for double-layer thick-walled concrete cylinder with different modulus

The stress state of thick-walled cylinder will be improved when it is composed of multi-layer concrete with different Young’s modulus of elasticity. The optimum design method for double-layer concrete cylinders is discussed in this paper. When the modulus of the inner-layer concrete is less than the outer one, the stress concentration on the cylinder inner surface will be relieved and the maximum tangential stress may be transferred from the inner surface of inner-layer to the inner surface of outer-layer, where is in triaxial stress state. The elastic limit bearing capacity of double-layer concrete cylinder will be improved due to the high compressive strength of concrete in triaxial stress state. Compared with the conditional single-layer thick-walled cylinder, the thickness of the double-layer cylinder can be reduced evidently. On the basis of stress solution of double-layer cylinder and by using the mixed penalty function method, the minimum wall thickness required, the best thickness ratio and the modulus ratio of inner layer to outer layer are calculated for cases in which the external load and uniaxial compressive strength are known already. If the thickness and uniaxial compressive strength is given, the best thickness ratio and modulus ratio of inner layer to outer layer can also be proposed by using the mixed penalty function method.