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A novel seaweed and mussel inspired bilayer anti-oil-fouling and antifogging coating was proposed. The coating shows water resistance, mechanical durability, and long-term environmental stability. The coating performs good in anti-oil-fouling and anti-fogging. [Display omitted] Ecofriendly fabrication of anti-oil-fouling materials is of interest. Surfaces with underwater superoleophobicity have been fabricated which exhibit limited mechanical durability and water resistance. In this study, we report on a bioinspired bilayer design of a transparent anti-oil-fouling coating. Seaweed surfaces show anti-oil-fouling in the sea due to its high surface hydration ability. Mussels can adhere tightly onto a surface with good stability in the sea by virtue of its levodopa-containing secretions. The surface layer was fabricated using a crosslinked combination of carboxymethyl cellulose (CMC) and sodium alginate (AlgS) inspired by seaweed, with the addition of calcium ions. Polydopamine (PDA), a derivative of levodopa, was used as the underlayer to enhance bonding strength and water resistance. Oil that adhered to the coated surface was spontaneously detached upon immersion in water. The mechanism underlying this anti-oil-fouling effect was elucidated using Gibbs free energy theory. The coating exhibited mechanical durability and water resistance. The coating is transparent and preserves the original color of the substrate. The coated glass showed stable anti-fogging and anti-frost performance. These coatings hold promise for a wide range of anti-oil-fouling applications. [ABSTRACT FROM AUTHOR]

The effect of the Zn/Mg ratio on microstructures, mechanical properties and corrosion performances of Al-Zn-Mg alloys was studied. Microstructures were characterized using the optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). Tensile tests, intergranular corrosion (IGC) and stress corrosion cracking (SCC) tests were conducted to study the properties. Microstructures results indicated that with the decrease of the Zn/Mg ratio, the recrystallization proportion and the fraction of second phase decreased, while the size of η' (MgZn2) phases in grain interior also significantly decreased. The number density of η' phases in grain interior increased and grain boundary precipitates developed discontinuous distribution with the decrease of the Zn/Mg ratio. These microstructures contributed to the significant improvement of the strength and corrosion resistance. The tensile strength and yield strength increased by 34.1% and 47.4%, respectively, with the Zn/Mg ratio decreased from 11.4 to 6.1. Calculating results indicated that the enhancement of strength mainly contributed from the solid-solution strengthening, grain-boundary strengthening and precipitation strengthening. The intergranular corrosion degree was greatly relieved and the stress corrosion sensitivity index decreased from 0.031 to 0.007 with the Zn/Mg ratio decreased from 11.4 to 6.1. [ABSTRACT FROM AUTHOR]

The effect of multi-stage aging heat treatments on the hardness, tensile strength, electrical conductance, and exfoliation corrosion (EXCO) resistance of the Al–Zn–Mg–Cu alloy has been studied through the Vickers hardness, tensile, conductivity, and EXCO testing combined with microstructure characterization using a transmission electron microscope. Experimental results demonstrated that multi-stage aging conditions could effectively enhance the localized corrosion resistance through a lower strength loss compared to T6 aging condition (120 °C/24 h). The designed four-step aging (FSA) treatments could improve the EXCO properties to PB degree along with the ultimate tensile strength and yield strength to 373 MPa and 324 MPa, respectively. The development trend of localized corrosion resistances has been further verified using electrochemical impedance spectroscopy and polarization dynamic curves. Microstructures results indicated that dense precipitates in matrix, discontinuous coarse precipitates on grain boundaries, and a proper precipitation free zone play an important role in balancing the strength and corrosion properties of the FSA aged alloy. • Multi-step aging treatment was designed in Al–Zn–Mg alloy. • The balance of strength and exfoliation corrosion were studied. • The effect of microstructure evolution on the corrosion resistance was studied. • The four-step aging treatment could improve the exfoliation corrosion resistance. • The designed four-step aging treatment could maintain higher yield strength. [ABSTRACT FROM AUTHOR]

The in-situ SEM observations and Line-scanning methods were used to observe the atomic concentration distribution and evolution of main elements in intermetallic phase at different solid solution temperatures. The results indicated that the atomic distribution of main elements in η (MgZn 2), S (Al 2 CuMg), Fe-containing (Al 7 Cu 2 Fe) intermetallic phases are parabolic through these phases, while the non-main elements uniformly distribute in matrix. The results of Differential Scanning Calorimetry (DSC) and Energy Dispersive Spectra (EDS) indicated that the Zn atoms dissolved into the matrix between 245 and 430 °C, under which the process of η phase transits to S phase occurred. The Cu element of S (Al 2 CuMg) phase has an obviously diffusion rate at 450 °C, while the Mg element has an obviously diffusion rate when the temperature is higher than 460 °C. Afterwards the atomic concentration dissolution was modelled by diffusion law, and the model results is corresponding to the linear rule, which agrees with the experiment results. • The in-situ SEM and Line-scanning methods were used to study the intermetallic. • The atomic distribution of elements in phases are parabolic. • The atomic concentration dissolution was modelled by diffusion law. • The diffusion temperature ranges of Zn, Cu and Mg atoms was studied. [ABSTRACT FROM AUTHOR]