An inorganic–organic coating based on glycidyl-functionalized silica and zirconia was synthesized by sol-gel technology to protect three types of AlMgSi (6XXX series) alloys against corrosion in aerospace applications. Different parameters such as the solid content, the organic/inorganic ratio of the sols and the deposition conditions were studied with the aim to achieve a tradeoff between the corrosion protection, antistatic performance and low vacuum-induced outgassing. Those parameters directly influence the thickness and the density of the coatings, and therefore the barrier effect against corrosion and the contact electrical resistance, which are affected in opposite ways. To obtain a low contact electrical resistance, silver nanowires (NW) with a high aspect ratio were loaded in the sol-gel matrix with the aim to create a conductive path through the hybrid coating with a low concentration of NWs. The coatings were adapted for AA6063, AA6061 and AA6082, and they all showed an outstanding anti-corrosion performance in different artificial weathering tests, whereas electrochemical impedance spectroscopy permitted the identification of the most critical parameters affecting water uptake. An antistatic performance was demonstrated by the low contact electrical resistance of the coated AA6061 and AA6063 alloys, although the incorporation of NWs showed a detrimental effect on the corrosion protection compared with the unloaded coating.

The preparation of cation-exchange membranes by compression molding of sulfonated EPDM-polypropylene blends is described. Concentration potentials measured in a two-compartmental cell with configuration <mml:math display="inline"><mml:mrow><mml:mi>Ag</mml:mi><mml:mo>∕</mml:mo><mml:mi>AgCl</mml:mi><mml:mspace width="0.3em"></mml:mspace><mml:mi>HCl</mml:mi></mml:mrow></mml:math>Ag∕AgClHCl solution <mml:math display="inline"><mml:mrow><mml:mo>(</mml:mo><mml:msub><mml:mi>C</mml:mi><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msub><mml:mo>)</mml:mo><mml:mo>∕</mml:mo></mml:mrow></mml:math>(C1)∕ membrane∕ <mml:math display="inline"><mml:mrow><mml:mi>HCl</mml:mi></mml:mrow></mml:math>HCl solution <mml:math display="inline"><mml:mrow><mml:mo>(</mml:mo><mml:msub><mml:mi>C</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:mo>)</mml:mo></mml:mrow></mml:math>(C2) <mml:math display="inline"><mml:mrow><mml:mi>AgCl</mml:mi><mml:mo>∕</mml:mo><mml:mi>Ag</mml:mi></mml:mrow></mml:math>AgCl∕Ag ., are a linear function of <mml:math display="inline"><mml:mrow><mml:mi>log</mml:mi><mml:mspace width="0.2em"></mml:mspace><mml:msub><mml:mi>a</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>loga2 (= <mml:math display="inline"><mml:mrow><mml:msub><mml:mi>C</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi>γ</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>C2γ2 , where <mml:math display="inline"><mml:mrow><mml:msub><mml:mi>C</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>C2 and <mml:math display="inline"><mml:mrow><mml:msub><mml:mi>γ</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>γ2 are, respectively, the concentration and activity coefficient of the solution in compartment 2 keeping constant the concentration in compartment 1, <mml:math display="inline"><mml:mrow><mml:msub><mml:mi>C</mml:mi><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>C1 . The values of the proton transport numbers, <mml:math display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mover accent="true"><mml:mi>t</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover></mml:mrow><mml:mo>+</mml:mo></mml:msub></mml:mrow></mml:math>t¯+ , decrease from 0.99 to 0.94 when the ratio <mml:math display="inline"><mml:mrow><mml:msub><mml:mi>C</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:mo>∕</mml:mo><mml:msub><mml:mi>C</mml:mi><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>C2∕C1 increases from 0.1 to 5, nearly the same decrease reported for Nafion 117 in the same variation of concentration ratios. Proton conductivities at <mml:math display="inline"><mml:mrow><mml:mn>25</mml:mn><mml:mo>°</mml:mo><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:math>25°C are <mml:math display="inline"><mml:mrow><mml:mn>9.84</mml:mn><mml:mo>×</mml:mo><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>4</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>9.84×10−4 and <mml:math display="inline"><mml:mrow><mml:mn>7.25</mml:mn><mml:mo>×</mml:mo><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>4</mml:mn></mml:mrow></mml:msup><mml:mspace width="0.3em"></mml:mspace><mml:mi mathvariant="normal">S</mml:mi><mml:mo>∕</mml:mo><mml:mi>cm</mml:mi></mml:mrow></mml:math>7.25×10−4S∕cm , respectively, for water-saturated membranes containing 20 and 10% of polypropylene, more than one decade below the value reported in the literature for the conductivity of Nafion membranes at the same temperature. These conductivities at <mml:math display="inline"><mml:mrow><mml:mn>90</mml:mn><mml:mo>°</mml:mo><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:math>90°C amount to <mml:math display="inline"><mml:mrow><mml:mn>8.35</mml:mn><mml:mo>×</mml:mo><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>8.35×10−2 and <mml:math display="inline"><mml:mrow><mml:mn>1.03</mml:mn><mml:mo>×</mml:mo><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msup><mml:mspace width="0.3em"></mml:mspace><mml:mi mathvariant="normal">S</mml:mi><mml:mo>∕</mml:mo><mml:mi>cm</mml:mi></mml:mrow></mml:math>1.03×10−2S∕cm , respectively.