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In the present study, a polymer‐derived silicon oxycarbide (SiOC) ceramic layer has been coated on stainless steel 304 (SS304) to improve corrosion resistance in a seawater environment. The surface of SS304 is dip‐coated with vinyl‐functionalized polysiloxane, followed by pyrolysis under argon at 800°C to obtain SiOC layer with a thickness of about 1 μm after two‐fold coating/pyrolysis steps. Structural characterization of the samples was performed by fourier transform infrared (FTIR), X‐ray diffraction, Raman spectroscopy, and scanning electron microscopy. Electrochemical characterization of SS304 and SiOC‐coated SS304 is performed in 0.6 M NaCl solution. Potentiodynamic polarization measurements showed improved corrosion resistance of SiOC‐coated SS304 with a very low corrosion current density of 4.14 × 10−9 A/cm2 whereas for uncoated SS304 corrosion current density of 4.56 × 10−7 A/cm2 was measured. Electrochemical impedance spectroscopic study confirmed superior corrosion resistance behavior of SiOC‐coated SS304 over uncoated SS304. [ABSTRACT FROM AUTHOR]

Polymer-derived amorphous silicon oxycarbide (SiOC) ceramics are designed for hydrogen separation at high temperatures. To form amorphous SiOC top-coating with the thickness of about 300 nm, tubular porous γ-Al2O3/α-Al2O3 substrates with gradient porosity are threefold coated by vinyl-functionalized polysiloxane and pyrolyzed at 700 °C under argon. N2-physisorption measurement confirms formation of microporous material with a specific surface area of about 400 m2 g-1. Single gas permeance characterization of the SiOC membrane at 300 °C reveals H2/CO2 and H2/SF6 ideal permselectivities of about 10 and 320, respectively. The experimental gas permeance data are modeled using solid-state diffusion (for He and H2) and gas translational diffusion (for CO2 and SF6) mechanisms. [ABSTRACT FROM AUTHOR]

Low-layered, transparent graphene is accessible by a chemical vapor deposition (CVD) technique on a Ni-catalyst layer, which is deposited on a <100> silicon substrate. The number of graphene layers on the substrate is controlled by the grain boundaries in the Ni-catalyst layer and can be studied by micro Raman analysis. Electrical studies showed a sheet resistance ( Rsheet) of approximately 1435 Ω per □, a contact resistance ( Rc) of about 127 Ω, and a specific contact resistance ( Rsc) of approximately 2.8×10−4 Ω cm2 for the CVD graphene samples. Transistor output characteristics for the graphene sample demonstrated linear current/voltage behavior. A current versus voltage ( Ids- Vds) plot clearly indicates a p-conducting characteristic of the synthesized graphene. Gas-sensor measurements revealed a high sensor activity of the low-layer graphene material towards H2 and CO. At 300 °C, a sensor response of approximately 29 towards low H2 concentrations (1 vol %) was observed, which is by a factor of four higher than recently reported. [ABSTRACT FROM AUTHOR]