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3-glycidoxypropyl-trimethoxysilane (GPTMS) functionalized graphene oxide (GO) was used to synthesize graphene-based film for corrosion protection of AA2024-T3 aluminum alloy. GO covalently reacted with the silanol group from the hydrolyzed GPTMS monomer, forming silane functionalized GO (silane-GO) linked by C-O-Si covalent bonds. The silane coupling agents acted as a ‘bridge’ to link GO to adjacent GO and to the metal surface by covalent bonds. The corrosion protective properties of silane-GO film were determined by electrochemical measurements and immersion tests. Results indicated that silane-GO film provided effective protection for the metal substrate and the readily corrodible areas (at the periphery of protruding constituent particles). This was due to the good barrier property from layered GO, the filled defects and gaps between GO, and the enhanced adhesion strength of GO to adjacent GO and the film to the substrate. The protective efficiency of silane-GO film was up to 95.0%. The successful application of silane-GO film on AA2024-T3 aluminum alloy suggests that there is the considerable potential for broad application of graphene-based protective film on metals, even on the metals with corrosion-sensitive areas.

The synthesis of inhibitor nanocontainers with two-dimensional (2D) structure using graphene oxide and layered double hydroxides (GO/LDHs) via a coprecipitation method was studied. The corrosion inhibitors of vanadate anions (VOx−) and 2-mercaptobenzothiazole anions (MBT−) were loaded into the GO/LDHs nanocontainers by an anion exchange reaction and the products retained the 2D structure. GO/LDHs loaded with VOx− (GO/LDHs-VOx−) were added into a sol-gel coating on AA2024-T3. It was found that the corrosion protection of the sol-gel coating was effectively enhanced. No serious corrosion was observed on the alloy after 240 h of salt spray test. The enhancement of the protective properties was attributed to two aspects: the improvement of the barrier property from the good dispersion of the additive with the 2D structure and the good barrier of GO sheets, and the corrosion inhibition of vanadate anions. In other words, the protection mechanism was that GO/LDHs-VOx− provided the coating active and improved passive protection simultaneously.

A novel reflective metasurface which presents different reflection phases to different polarization waves is designed in this article. The metasurface is used as the ground plane of a Fabry‐Pérot cavity (FPC) antenna. The radiator of the FPC antenna is a dual‐band patch antenna which has different polarizations in different bands, so by tuning the reflection phase of the metasurface correctly, the FPC antenna can work in two frequency bands. A prototype antenna is fabricated and measured. The measured results show that the antenna can operate at 8.35‐8.56 GHz (2.5%) in x‐polarization and 9.5‐10.1 GHz (6.1%) in y‐polarization. The maximum realized gains of the antenna in two bands are 17.6 dB at 8.75 GHz and 19 dB at 9.8 GHz. The measured results agree well with the simulated results which confirm the correctness of the design.

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