Adhesion strength in laminated glazings containing multilayer solar control coatings

We report on the mechanical and optical properties exhibited by a five layer laminated glazing (glass/PVB/PET/PVB/glass) in which a 0.1 mm thick polyethylene-terephthalate (PET) sheet carries a 70?C110 nm CuS solar control coatings on either one or both sides of it and laminated with 0.38 mm clear polyvinyl-butyral (PVB) sheets in an autoclave at 135°C for 30 min under a pressure, 13 kg/cm². The CuS coating was obtained by chemical deposition at 28°C during 1 h (70 nm) or 2 h (110 nm). The optical transmittance (T) of these laminated glazing is less than 1% in the ultraviolet region; 17?C32% in the visible region, and 4?C12% in the infrared region, depending on the CuS film thickness and whether the PET sheet is coated on one or both sides. The specular reflectance (R) of the glazing in the visible region is similar to that of a monolithic glass: about 10%, but in the infrared it increases toward 20%. The mechanical properties were evaluated through a compressive test giving interfacial adhesive strength of the laminated: 1.5?C2 MPa for PET with a single side CuS coating and 3.4 MPa for the laminate with a PET coated on both sides.     

Tribological Behavior of TiC/a-C:H-Coated and Uncoated Steels Sliding Against Phenol–Formaldehyde Composite Reinforced with PTFE and Glass Fibers

Tribological experiments on phenol–formaldehyde composite reinforced with polytetrafluoroethylene (PTFE) and glass fibers were performed against 100Cr6 steel and TiC/a-C:H thin film-coated 100Cr6 steel. In both cases, the coefficient of friction increases with increasing sliding distance until a steady-state value is reached. Although the steady-state values of the coefficient of friction are very close and ultralow, the wear rate of the PTFE composite liner at a long sliding distance (1,000 m) is reduced when the steel ball is coated with the TiC/a-C:H coating. This behavior is mainly attributed to the smoother surface after long sliding and the improved wear resistance of TiC/a-C:H coating. PTFE transfer films are evident on the surfaces of the hard counterparts. The average thickness of the transfer film on TiC/a-C:H-coated surfaces is about 3.8 nm. On the surface of uncoated steel ball, a continuous but non-uniform transfer film of around 13.9 nm average thickness was found.     

Vacuum suction aid for microlens array formation using LIGA-like process

Microlens array fabrication using a vacuum suction process combed with the LIGA-like process is presented in this paper. The circular patterned array was designed on a photomask and transferred onto a substrate using photoresist patterning. Electroforming technology was used to convert the photoresist patterns into a metallic molds with an array of nozzles. Liquid JSR resist was spun onto the substrate joining the metallic mold to remove microlens array under vacuum conditions. The exposure energy and vacuum pressure were essential parameters in the microlens array manufacturing process. Microlens arrays with 50 μm in diameter at −50 cm-Hg vacuum pressure and 100 μm in diameter at −60 cm-Hg vacuum pressure were successfully formed. The produced microlens arrays presented smooth measured surface profiles coincident with the optical lens geometry.     

Design,fabrication and testing of a compact large-field-of-view infrared compound eye imaging system by precision glass molding

Bionic artificial compound eyes inspire a promising field of miniaturized imaging systems. In this research, a novel infrared (IR) three-dimensional (3D) compound eye imaging system, consisting of a double-side molded 3D microlens array and an aperture array, was designed and fabricated by combining modulated slow-tool-servo diamond turning and precision glass molding. To facilitate the complex profiles on the mold inserts, two novel slow-tool-servo strategies were adopted, namely virtual-axis based diamond broaching and adaptive diamond turning. This microlens array consists of 3 × 3 channels for a field of view of 48° × 48° with a thickness of 1.8 mm. The freeform microlens array on a flat surface was employed to steer and focus the incident light from all three dimensions to a two-dimension (2D) infrared imager. Using raytracing, the profiles of the freeform microlenses of each channel were optimized to obtain the best imaging performance. To avoid crosstalk among adjacent channels, a 3D printed three-dimensional micro aperture array was mounted between the microlens array and the IR imager. The imaging tests of the infrared compound-eye imaging system using the molded chalcogenide glass lenses showed that the asymmetrical freeform lenslets were capable of steering and forming images within the designed field of view. Compared to a conventional infrared camera, this novel microlens array can achieve a considerably larger field-of-view while maintaining low manufacturing cost without sacrificing image quality.     

Optical characteristics of silver film on the moth-eye structure

The development of coating optics to lower the reflected light and thereby to increase the optical efficiency of an optical system has been a very important issue for many years. Conventional solutions to this, such as multilayered alternation of high and low refractive index layers, often lead to an expensive coating process. Recently, the use of antireflection structured (ARS) surface, which is called “moth-eye structure”, has been proposed as an applicable option based on both the theoretical and experimental studies. In the current study, the experimental results of the reflectance and transmittance of two different thicknesses of silver films deposited on the moth-eye structure were carried out. The moth-eye structure arrays were fabricated by holographic exposure and photolithographic processes on the polymer film. The structure arrays were consisted of periodic length of about 300 nm, with the diameter of about 250 nm and the height of 150 nm. Compared with the silver coating film on the flat PET substrate, the optical property of the silver coating film on the moth-eye structure showed a better result for the anti-reflection application. The 25 nm-thick silver film on the moth-eye structure is suggested to be applied for the car window glass of antireflective films to obtain the high performance of heat insulation with acceptable transparency in the visible range.     

小口径非球面玻璃透镜模压成形

随着消费电子行业的增长和人们对轻便易携带的高性能产品的需求,非球面玻璃透镜的需求量持续增长。与传统冷加工方法相比,模压成形技术因具有低成本、批量生产的能力而成为一种更有前途的加工方法,尤其适合中小口径非球面透镜的生产。非球面玻璃透镜的模压成形技术是一项涉及玻璃材料、超精密模芯加工、镀膜、模压成形工艺及成仿真等诸多领域的综合技术。因此,有必要对其中影响成形质量的关键技术进行系统分析和深入研究,探讨模压成形技术现状和存在的问题。对光学玻璃的物理化学性质、主要构成成分、粘弹性、低熔点及环保的发展趋势、预形体的选择进行综合分析;对模芯材料的开发、非球面模芯的单点金刚石车削技术、纳米磨削技术、超精密研抛技术、复合加工技术、镀膜材料、镀膜技术做了详细介绍;阐述模压成形技术及仿真技术的研究现状及最新进展;并对未来发展趋势进行预测与展望。     

玻璃精密模压成形的研究进展

玻璃精密模压成形是一种高效率、绿色环保的先进光学元件制造技术,近年来得到了飞速发展。本文首先介绍了光学元件的需求与种类,提出玻璃精密模压成形技术存在的问题。综述了国内外近年来精密模压成形光学透镜的重要研究进展,其中包括光学玻璃材料、模具材料与涂层、模具加工、模压过程仿真以及各种参数对透镜质量的影响。阐述了光学模压成形元件的坯料、镀膜技术和冷加工技术、成形元件的残余应力分布以及折射率、模具与玻璃间摩擦效应、模具的补偿技术、成形透镜质量的预测、模压技术的其他应用等。最后,对未来光学玻璃精密模压成形趋势进行了预测。     

涂层材料特性对滚子轴承润滑性能的影响*

涂层材料被广泛应用于滚子轴承中以改善界面性能和提高疲劳寿命,为了探讨涂层材料性能对滚子轴承润滑性能的影响,基于流体力学与接触力学理论,建立带涂层的有限长线接触弹流润滑模型,探讨不同载荷、速度以及涂层材料特性对油膜压力、油膜厚度的影响。研究表明：随着涂层厚度的增加,硬涂层使得最小油膜厚度先增加后减小,而软涂层轻载时使得最小油膜厚度先减小后增加,重载时最小油膜厚度一直减小;随着速度的增加,出口区二次压力峰值增加,硬涂层尤为明显,并且油膜厚度也增加,油膜平坦区域减小,出口区油膜紧缩值增加。为提高润滑性能,当使用较厚软涂层时应考虑增加滚子凸度量,而使用较厚硬涂层时应考虑减小滚子凸度量。     

Anti-oxidant mechanism of TiAlN/SiN decorative films on borosilicate glass by magnetron sputtering

The black TiAlN decorative film was prepared on the borosilicate glass by the magnetron sputtering in equipment with multiple vacuum chambers. The transparent SiN protective layer was deposited on the surface of the TiAlN film to keep the black color invariant at the high temperature. The structure of the TiAlN/SiN film was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). The coating adhesion was measured by scratch tester. The TiAlN film has a columnar crystal structure with a thickness of 200 nm, and the top SiN layer is amorphous with a thickness of 100 nm. The coated borosilicate glass with the TiAlN/SiN films still retains the black color after oxidation at 600 °C in atmosphere. While the oxidation temperature elevates to 700 °C, the color of the TiAlN/SiN films begins to change. The top SiN layer plays a role as the barrier against oxygen diffusion into the inner TiAlN layer. The thin self-formed aluminum oxide layer was generated on the surface of the SiN layer and it contributes to the improvement of anti-oxidant property of the inner TiAlN layer. However, the thick self-formed aluminum oxide layer leads to the color change of the black TiAlN film. The thermal oxidation benefits the improvement of the adhesion for the TiAlN/SiN films with glass substrate.     

The tribological behaviour of glass filled polytetrafluoroethylene

Polymers and polymer composites are steadily gaining ground over metals in the field of engineering applications in tribology. Laboratory wear tests were carried out under ambient temperatures with no lubricant as well as in distilled water at an average sliding velocity of 0.2 m/s and contact pressures of 2.6–6.4 MPa. Three forms of glass viz. glass fibres, glass beads and glass flakes, each with a content of 25% weight were used in this study. Both hollow and solid glass beads were used. The sliding wear of the different glass filled PTFE composites was dependent on their ability to form transfer films on the counterface. The glass bead filled PTFE showed comparatively thicker films and higher wear rates than other forms of glass filled grades. The glass fibres and solid glass beads showed the lowest wear whilst hollow beads showed the highest under both low and high pressures due to crumbling and crushing of the beads during the sliding process. The glass flake filled PTFE showed relatively high but stable wear results up to 4.5 MPa above which the wear rate increased dramatically. A marginal increase in wear was achieved by using high aspect ratio glass fibres to the PTFE matrix. No correlation between the size of glass reinforcement and wear rate was established. The addition of a lamellar solid lubricant to the glass fibres reduced both the wear and friction of PTFE. The study of the transfer film growth by means of an optical microscope revealed that it was due to the mechanical interlocking of the polymer fragments into the metal asperity valleys. The compositional changes in the transfer film were studied by XPS which, among other things, showed presence of metal fluoride on the metal counterface.     

基于电场驱动喷射微3D打印的大面积微透镜阵列制造研究

大面积圆形、柱状及梯度折射率微透镜阵列在裸眼3D、光学传感、仿生学、医疗内窥镜等领域具有非常广泛的需求,然而,如何实现大面积多类型微透镜阵列的简单化、低成本、高效率制造是学术界与产业界共同面临的一项挑战性难题。基于电场驱动喷射微3D打印技术,提出了一种可实现大面积多类型微透镜阵列制备的新方法,通过实验揭示了主要工艺参数（电压、气压,打印速度）对制备的不同类型微透镜形貌与质量的影响与规律,利用提出的方法并结合优化的工艺参数,在玻璃基底上分别实现了面积为120 mm×120 mm、100 cm×45 cm的圆形与柱状微透镜阵列的制造,在柔性PET基底上实现了面积为160 mm×160 mm的圆形微透镜阵列的制造,利用电场驱动喷射微3D打印的多层打印模式实现了折射率梯度变化范围为0.1的梯度折射率微透镜阵列的制造。实验结果表明,制备的微透镜阵列具有良好的几何与光学性能,基于电场驱动喷射微3D打印大面积、多类型微透镜阵列制造方法具有效率高、成本低、批量化的显著优势,为大面积多类型微透镜阵列制造提供了一种全新的解决方案。     

光学薄膜元件在舞台灯光中的应用

舞台灯光灯具采用传统光学系统,光学系统主要实现灯光的视觉效果如光强、颜色及其他一些特殊效果。而光学系统中的各种光学元件都需要光学镀膜。现主要介绍舞台灯光中常用的光学薄膜元件类型、设计膜系和光谱曲线,探讨光学镀膜材料和工艺,以及光学薄膜元件的应用场合。     

在线Low-E玻璃光学特性机理及其功能层光学常数的确定

从D rude色散理论和薄膜光学的基本方法出发,用理论公式对在线Low-E玻璃的透射谱线进行拟合,得到了Low-E玻璃功能层的光学常数。利用Burstein-M oss理论,计算得到了功能层的自由载流子浓度;理论计算与实验结果的一致性表明,D rude理论不仅能很好地定量解释在线Low-E玻璃的光学特性,而且为在线Low-E玻璃光学常数的理论计算提供了一种切实可行的方法。     

Investigating Corrosion Performance and Corrosive Wear Behavior of Sol–gel/MAO-Coated Mg Alloy

In this study, a hydroxyapatite composite coating was prepared by a sol–gel technique on the micro-arc oxidation (MAO)-coated AZ31 Mg alloy to seal the micro-pores. The composite coating achieved a larger hardness value and two times thickness more than pure MAO coating. The corrosion and wear resistance of the sol–gel/MAO coating in simulated body fluid were investigated compared to MAO coating. It was found that the composite coating presented a positive corrosion potential and a lower corrosion current density than MAO coating. The sol–gel/MAO composite coating could provide more effective barrier against corrosive ions than single MAO coating for AZ31 alloy. In the wear tests, a ball-on-disk tribometer was used to study the effect of loads on the wear properties of the coatings at 37 °C. The wear resistance of sol–gel/MAO composite coatings was apparently superior to MAO coating. The wear mechanisms of abrasion and adhesion in composite coatings are investigated. Finally, two physical models for the corrosion and sliding wear mechanisms of sol–gel/MAO composite coatings are proposed, respectively.     

Vacuum suction aid for microlens array formation using LIGA-like process

Microlens array fabrication using a vacuum suction process combed with the LIGA-like process is presented in this paper. The circular patterned array was designed on a photomask and transferred onto a substrate using photoresist patterning. Electroforming technology was used to convert the photoresist patterns into a metallic molds with an array of nozzles. Liquid JSR resist was spun onto the substrate joining the metallic mold to remove microlens array under vacuum conditions. The exposure energy and vacuum pressure were essential parameters in the microlens array manufacturing process. Microlens arrays with 50 μm in diameter at -50 cm-Hg vacuum pressure and 100 μm in diameter at -60 cm-Hg vacuum pressure were successfully formed. The produced microlens arrays presented smooth measured surface profiles coincident with the optical lens geometry.     

Prototype fabrication of a composite automobile body based on integrated structure

This paper describes the integrated fabrication and assembly approach used to replace a steel body cover in Samand Sarir automobile by composite one because composite could perform higher mechanical performance, i.e., strength, stiffness, and impact absorption energy at low velocity. Considering the integrated body as base design criteria, the steel cover is redesigned and fabricated by composite material. Tensile, flexural, and charpy impact tests were carried out to determine the properties of woven fabric laminated composite in [0/90°] and [±45°] fiber orientations. The selected composite laminate shows 2.9 times impact resistance; its desirability factors are improved 1.8 times for strength and 3.35 times for stiffness. Using finite element method, the impact of the composite body cover was simulated by ABAQUS for several thicknesses and fiber orientations. The FEM results indicate that finally laminated composite [0/90°]₇ can improve the crashworthiness of composite part in comparing to steel body cover. The integrated 3D preform of glass woven fabric was stitched like the shape of 3D model of body cover and placed in mold for prototype fabrication. It can be concluded that vacuum bagging as suggested fabrication method could be suitable for 3,000–5,000 annual production volume. Eventually, the fabricated composite body cover weighed 1.7 kg, which is 42% lighter than the steel body cover.     

大面积户外照明光学薄膜膜厚均匀性研究

户外照明采用大面积光学薄膜,对薄膜均匀性提出较高的要求。采用平面公自转行星夹具镀制户外照明用大面积光学薄膜,分析计算了光学薄膜膜厚的均匀性,探讨各个参数对膜厚均匀性的影响,经测试分析,得到理论偏差和实际偏差结果。     

HVOF-Sprayed Adaptive Low Friction NiMoAl–Ag Coating for Tribological Application from 20 to 800 °C

An adaptive NiMoAl–Ag composite coating was deposited by high-velocity oxy fuel spraying, and its tribological properties from 20 to 800 °C under unlubricated conditions were evaluated using a CSM high-temperature tribometer. Scanning electron microscopy, X-ray diffraction and Raman spectroscopy were used to characterize the coating and corresponding wear tracks to determine the lubrication mechanisms. The results showed that the friction coefficient of the NiMoAl–Ag composite coating was around 0.3 from 20 to 600 °C and reached the lowest value of 0.09 at 800 °C. Meanwhile, wear rates of the coating were maintained on the order of 10^?5 mm³/N m at the test temperatures except for 400 and 600 °C. Characterization of the NiMoAl–Ag coating revealed that silver provided lubrication below 400 °C. Ag₂Mo₂O₇ and Ag₂MoO₄, which were formed through tribochemical reactions, acted as high-temperature lubricants above 400 °C. It was especially proposed that silver in a nearly molten state was effective in reducing the friction of the NiMoAl–Ag coating at 800 °C. Moreover, a comprehensive lubrication mechanism model of an NiMoAl–Ag composite coating at 800 °C was established to explain the extremely low friction coefficient and wear rate of the coating.     

Role of Third Bodies in Friction and Wear of Cold-Sprayed Ti and Ti–TiC Composite Coatings

Titanium (Ti) and Ti-based alloy wear performance is often poor unless coating or lubricants are used. An alternative is to use hard phase reinforcement. Cold spray is a relatively new method to deposit composite coatings, where here we report the deposition of a Ti–TiC coating and its sliding wear behavior. Mixtures of mechanically blended Ti–TiC with various TiC content were injected into a de Laval nozzle and sprayed onto substrates. Two composite coatings and a pure Ti coating are reported here, where the as-sprayed compositions of the composites were 13.8 and 33.4 vol% TiC. Reciprocating dry sliding wear was performed using a custom-built in situ tribometer. All tests were conducted with a sliding speed of 3 mm/s and at a normal load of 0.5 N. Using a transparent sapphire hemisphere of 6.25 mm as counterface, dynamic behavior of third bodies was directly observed. It was found that adhesive transfer of Ti was the primary wear mechanism for the Ti coating, with oxidative and abrasive wear also occurring for longer sliding cycles. The superior wear resistance of the composite coatings compared to Ti was related to dual function of TiC particles, where they reinforced the Ti matrix and facilitated the formation of a stable and protective tribofilms. The tribofilms contained carbonaceous material that provided easier shear and lower friction. The formation of these tribofilms was highly dependent on the TiC particles, which contained excess carbon compared to the equilibrium composition. Higher TiC content was more effective in quickly developing and sustaining the tribofilms.     

Heat transfer in injection molding for reproduction of sub-micron-sized features

Heat transfer in injection molding was quantitatively measured with micro heat-flux sensors. The 0.1–10 micron-wide micro-grooves with aspect ratios of 0.5–1.0 were etched by focus ion beam on a Ni-plated mold. During the short time just after injecting, heat-flux in the mold was maximized to 10–50 W/cm², and heat transfer coefficient between plastic and mold was 0.27 W/(cm²K) with PMMA and 0.085 W/(cm²K) with PS. The maximum mold surface temperature just after injecting should be above the glass transition temperature of plastic, then reproducing sub-micron-wide micro-ridges.