Sunlight curable hybrid organic–inorganic methacrylic‐based coatings: analysis of the cure mechanism and functional properties

An experimental ultraviolet (UV) polymerizable hybrid organic–inorganic protective coating, mainly intended for the surface protection of porous calcareous stone substrates, has been recently proposed and patented. The hybrid product evidenced an extraordinary hydrophobicity character, able to guarantee a high protection of the stone against water actions, as well as a high traspirability. Furthermore, it is able to equal the performance of commercial available coatings, with the important adjunctive advantage to be free solvent. The application of this product involves the use of a “dual curing” treatment, necessary to harden the coating applied on the substrate, representing this latter a technological limit. The dual curing treatment consists of 6 hr of exposure to a UV‐lamp plus 1 hr at 140°C in oven. In order to avoid this procedure, not easy to realize in situ, two different modifications of the composition of the hybrid product are proposed in this paper. The first one allows the photopolymerization of the hybrid coating only by sunlight exposure. The second one, even though requiring a UV exposure to photo‐polymerize the coating, does not need the subsequent thermal treatment at 140°C. Several experimental characterizations were performed on the newly developed hybrid products, in order to select an optimal composition for the formulations. The selected innovative products were, finally, applied on a calcareous stone substrate, typical of Apulia Region (Pietra Leccese, PL). Both coatings exhibit excellent water‐repellent action and a slight variation of the natural stone color. Copyright © 2014 John Wiley & Sons, Ltd.     

冲击速度和磨粒粒度对FeCrAl/WC复合涂层冲蚀性能的影响

采用粉芯丝材作为原料,利用高速电弧喷涂技术制备了具有良好抗高温冲蚀磨损性能的FeCrAl/WC复合涂层;考察了650℃下冲击速度和磨粒粒度对复合涂层高温冲蚀磨损性能的影响.结果表明,复合涂层和20G锅炉钢的耐高温冲蚀磨损能力随着磨粒粒度的增加而有所提高;30°攻角下冲蚀率随磨粒粒度的变化速率比90°攻角下的小;同20G锅炉钢相比,复合涂层对速更加敏感,速度越低,FeCrAl/WC复合涂层的抗冲蚀磨损性能越好.     

无机类富勒烯过渡金属硫化物纳米材料的合成及其摩擦学应用研究进展

评述了无机类富勒烯（IF）与过渡金属硫化物（WS2和MoS2等）纳米材料的合成技术及其摩擦学应用研究的最新进展，外型为球形或近似于球形并具有嵌套中空结构的IF－WS2和IF－MoS2纳米果粒具有潜在的摩擦学应用前景；对含有IF－WS2纳米颗粒的复合材料和Ni-P复合镀层的研究表明，其比含有石墨和层状2H－WS2粉末的固体润滑剂具有更优异的摩擦学性能。     

镍基合金－碳化铬复合涂层耐磨特性的研究

用真空熔烧法在４５＃钢表面制取了镍基合金－碳化铬复合涂层，用扫描电子显微镜和Ｘ射线衍射仪分析了这种涂层的微观结构、物相组成和性能，并对这种涂层的耐磨特性进行了试验研究．结果表明：镍基合金－碳化铬复合涂层与底材形成了牢固的冶金结合，同时还含有较高比例的硬质相；碳化铬的加入使涂层的耐磨性显著提高，在给定的试验条件下分别于干摩擦和２０＃机械油润滑时，镍基合金－碳化铬复合涂层的耐磨性比４５＃钢的分别高５倍和１０倍以上     

Cr12MoV钢表面磁控溅射Ti/TiN涂层的摩擦磨损性能研究

采用非平衡磁控溅射方法在Cr12MoV钢表面制备了厚度约为3 μm的Ti/TiN涂层,测定了涂层的显微硬度,并通过划痕试验和摩擦磨损试验考察了涂层同基体的结合强度及其摩擦磨损性能.结果表明:Ti/TiN涂层能够显著提高Cr12MoV钢的表面硬度和承载能力;涂层同Cr12MoV钢基体的结合强度较高,划痕临界载荷高于60 N;与此同时,磁控溅射Ti/TiN涂层可以显著改善Cr12MoV钢的耐磨性能.这是由于磁控溅射Ti/TiN涂层硬度高且与Cr12MoV钢基体的结合强度较高所致.     

纳米金刚石对电沉积镍基复合镀层微观结构及抗磨性能的影响

利用直流电沉积技术制备了纳米和微米镍镀层,以及纳米金刚石增强镍基复合镀层,考察了纳米金刚石颗粒对纳米及微米镍基质的表面形貌、微结构、硬度及磨损性能的影响．结果表明：引入纳米金刚石使得微米镍镀层的硬度和抗磨性能显著提高;但引入纳米金刚石对纳米镍镀层硬度的影响不大,对镀层的抗磨性能则反而产生不利影响．     

Electrical and optical properties of Si-doped indium tin oxides as transparent electrode and anti-reflection coating for solar cells

We have studied the electrical and optical properties of Si-doped indium tin oxides (ITSOs) as transparent electrodes and anti-reflection coatings for Si-based solar cells. The ITSO thin films were obtained by co-sputtering of ITO and SiO₂ targets under target power control. The resistivity of the ITSO thin films deposited at 0.625 in terms of power ratio (ITO/SiO₂) were 391 Ωcm. In this condition, the ITSO thin films showed very high resistivity compared to sputted pure ITO thin films (1.08 × 10⁻³ Ωcm). However, refractive index of ITSO thin films deposited at the same condition at 500 nm is somewhat lowered to 1.97 compared to ITO thin films (2.06). The fabricated graded refractive index AR coatings using ITO, ITSO, and SiO₂ thin films kept over 80% of transmittance regardless of their thickness varing from 97 nm to 1196 nm because of their low extinction coefficient. As the AR coating with graded refractive indices using ITO, ITSO, and SiO₂ layers was applied to general silicon-based solar cell, the current level increased nearly twice more than that of bare silicon solar cell without AR coating.     

Nano-composite LiMnPO4 as new insertion electrode for electrochemical supercapacitors

Nano-composite olivine LiMnPO₄ (nC-LMP) was found to exhibit facile pseudo-capacitive characteristics in aqueous as well as non-aqueous electrolytes. We demonstrated employing nC-LMP as positive electrode in hybrid electrochemical capacitors namely Li-Ion hybrid capacitors (LIC). Adapting a simple CVD technique, nano-crystallites of LiMnPO₄ were coated with carbon monolayers of ∼2 nm thick to circumvent its poor intrinsic electronic conductivity. The novelty is that the single crystallites were intimately covered with carbon ring and networked to the neighboring crystallites via the continuous carbon wire-like connectivity as revealed from HRTEM analysis. Single electrode faradic capacitance of 3025 Fg⁻¹ (versus standard calomel reference electrode) was deduced for carbon coated LMP, the highest reported hitherto in Li⁺ aqueous electrolytes. Employing nC-LMP as working electrode versus an activated carbon (AC), we obtained a high specific energy of 28.8 Wh kg⁻¹ with appreciable stability in aqueous electrolytes whereas in nonaqueous electrolyte there is an obvious increase in energy density (35 Wh kg⁻¹) due to wider potential window. That is, a full cell version of LIC, AC|Li⁺|LMP, was fabricated and demonstrated its facile cycling characteristics via removal/insertion of Li⁺ within nC-LMP (positive electrode) and the electrosorption of Li⁺ into mesoporous carbon (AC) (negative electrode). Such cells ensured a typical battery-like charging and EDLC-like discharging characteristics of LIC type electrochemical capacitors (ECs) which are desired to enhance safety and energy densities.     

Controlling the infrared optical properties of rf-sputtered NiO films for applications of infrared window

In this paper, we will focus on an IR transmittance enhancement technique from the window material point of view by using metal oxides, especially nickel oxide (NiO). At first, anti-reflection (AR) coatings were modeled by using the optical properties of NiO films. The transmittance of the model was predicted using Swanepoel’s model and verified with NiO film prepared by rf magnetron sputtering. Also, post-deposition annealing was performed and was found to change the optical properties of the NiO film. Therefore, we analyzed the annealing effect on the IR optical properties of the NiO film. Furthermore, we confirmed the durability of the NiO film and verified the possibility of this material being used in infrared optics.     

粗糙表面涂覆目标的太赫兹波散射特性研究

对具有涂覆层目标的太赫兹波段粗糙表面的散射特性进行了研究. 考虑到表面粗糙度的影响, 可先对反射系数进行修正, 再利用反射系数对等效电磁流进行修正, 得到粗糙涂覆表面的等效电磁流, 然后在物理光学方程的基础上得到粗糙表面涂覆目标的雷达散射截面; 最后进行图形电磁学可视化计算, 并采用Visual C++对模型进行OpenGL显示, 提取像素面元的有效信息对所得理论进行了仿真分析, 研究了不同入射角度、不同频率、不同介质、不同粗糙度和不同涂层厚度下的太赫兹波电磁散射特性, 得到了一些有参考价值的结论.