分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-08
摘要: Aluminum alloys with novel binary anti-corrosion structures on the surface showing superhydrophobic properties were fabricated via chemical etching, anodic oxidation and chemical modification. Surface morphologies and chemical elements of the as-prepared films were investigated by Fourier transform infrared spectrometer, scanning electron microscopy and confocal laser scanning microscope. Surface wettability was investigated by the contact angle meter. Manipulation of surface morphology by anodic oxidation current density and the influence of surface chemical modification on the wettability were investigated. The anti-corrosion properties of the as-prepared films were characterized using an electrochemistry workstation. The results showed that surface water contact angle could reach 156 after chemical modification when the current density of anodic oxidation was 5 A dm 2. The corrosion potential (Ecorr) was positively increased from 1189 mV for bare Al alloys to 304 mV for the samples anodized at 5 A dm 2. The synergetic effect between the protective properties of air trapped in a low adhesion superhydrophobic surface and good barrier properties of the barrier layer of anodic oxidation film was remarkably enhanced the corrosion resistance of aluminum alloys. Influences of the anodic oxidation current density and the self-assembled films on the anti-corrosion performance were discussed in detail.
提交时间: 2017-05-02
摘要: Experimental results have revealed that mercapto functional sol-gel [MFS] coating can provide good protection for copper. However, information on the degradation behavior of MFS coating still limits in the literature and therefore needs further investigat
分类: 材料科学 >> 材料科学(综合) 提交时间: 2017-05-09
摘要: In order to improve the mechanical durability, polyurethane (PU) needs to be modified to enhance the tribological and anti-corrosion properties. In this work, we fabricated a series of PU composite coatings reinforced with functionalized graphene (FG) and functionalized graphene oxide (FGO). The structural and morphological features of the composite coatings were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The results showed that the dispersion and compatibility of graphene and graphene oxide were improved via chemical modification. Moreover, they effectively enhanced the tribological and anti-corrosion properties of PU composite coatings, whose optimized additive range was between 0.25 wt% and 0.5 wt%. The effect depends on the balance of lubrication and barrier of fillers and cracks generated by them. Finally, in comparison with FG/PU coatings, the FGO/PU coatings exhibited a better tribological property but worse anti-corrosion property owing to the abundant oxygenated groups of GO. They led to stronger interfacial interactions between FGO and the PU matrix, but destroyed the graphene lattice structure to some extent.
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: Engineered pillars, pits and grooves spaced 3, 6, 9 and 12 m apart were fabricated on siloxane modified acrylic resin films. The effect of feature size, geometry, and wettability on the settlement of different algae was evaluated. These films showed various antifouling performances to Ulothrix, Closterium and Navic- ula. For Navicula (length: 10–12 m), the feature size and geometry displayed a substantial correlation with the antifouling properties. The film with pillars spaced 3 m reduced Navicula settlement by 73% compared to the control surface. For Closterium (length: 45–55 m), their responses were governed by the same underlying thermodynamic principles as wettability, the largest reduction in Closterium, 81%, was obtained on the surface with grooves spaced 12 m apart. For Ulothrix (length: 5–8 mm), the surface also showed the best antifouling performance, the reduction ratio of the settlement on the surface with grooves spaced 12 m apart could even reach 92%. At last, physical fouling deterrent mechanisms for the films with various textures were analyzed in detail. The feature size and geometry display a substantial correlation with the antifouling properties when the size of fouling algae is close to the textures. With the increasing size for algae, antifouling performance was getting better on surface with pillars or grooves because the algae are bridged between two or more features other than stabilizing its entire mass on one single feature or able to settle between features.