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Anodic titanium dioxide (ATO) has been investigated for decades of years. It can be widely used in microextraction fiber for sample pretreatment because of its rich variety of morphologies such as nanotube, nanowires, nanoparticles and so on. In this work, TiO 2 nanotube clusters in situ growth were prepared on titanium substrate by anodization method. The effects of anodization distance, anodizing time and temperature of electrolyte were investigated. The results showed that uniform nanotube clusters coating can be obtained under the conditions of 1.5 cm anodizing distance, 50 min anodizing time and 60 °C anodizing temperature. On this basis, a novel, simple and fast octadecyl functionalization was followed by one step chemical self-assembly method based on the chemical reaction between octadecyltrichlorosilane and surface titanium hydroxyl groups (Ti-OH). The electrochemical scanning microscope (SEM), energy dispersive spectrometer (EDS) and XPS were employed for sample characterization, which showed that octadecyl groups were successfully assembled on the surface of TiO 2 nanotube clusters. Moreover, the surface corrosion resistance of the fibers was also tested by electrochemical methods. Unlabelled Image • A novel in-situ growth of TiO 2 nanotube clusters by anodization method was evaluated. • Octadecyl groups were one step self-assembled and the corrosion resistance is greatly enhanced. • The coating fabrication is facile, rapid and repeatable, which is expected to be used in many fields. [ABSTRACT FROM AUTHOR]

In this work, a novel 3D graphene/Fe 3 O 4 (G-Fe 3 O 4) nanocomposite was prepared by a facile one-pot hydrothermal process used to be adulterated into the varnish as an anticorrosive and electromagnetic shielding paint. It is confirmed that the skeleton structure of graphene can effectively inhibit Fe 3 O 4 agglomeration by Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) technique, and the G-Fe 3 O 4 nanocomposites can be well dispersed in the varnish for a longtime without settling. The graphene/Fe 3 O 4 composite varnish shows excellent corrosion resistance both in city water and seawater, besides its corrosion resistance is also superior to that of ordinary anti-rust paint. Moreover, the electromagnetic shielding test confirms that the as-prepared composite varnish shows well electromagnetic shielding performance. This new type of composite varnish has a broad application prospect to be used as urban exterior wall and ships paint. [ABSTRACT FROM AUTHOR]

The corrosion behavior and surface conductivity of type 446 stainless steel were investigated in the simulated cathode environment of proton exchange membrane fuel cell with 0.0005 M H2SO4 + 0.1 ppm F− solution at 80 °C under different polarization potentials by using electrochemical measurement methods, X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma optical emission spectroscopy (ICP-OES). The 446 stainless steel passivates spontaneously in the simulated environment. The current density and interface contact resistance (ICR) enlarge slightly with increasing the anodic polarization potential in the passive region. As the potential changes from 0.7 to 1.5 V vs. SCE, the current density and ICR increase markedly due to the occurrence of transpassivation, secondary passivation, and oxygen evolution. The ICR values are larger by about 24 mΩ cm2 after the polarization above 0.7 V vs. SCE. The polarization potential shifts from the passive region to oxygen evolution region, resulting in higher oxidized Fe and Mo contents in the product film on specimen surface and relatively more release of alloying constituents (especially Cr and Mo) into the solution. These are mainly responsible for the degradation of corrosion and surface conductivity properties. [ABSTRACT FROM AUTHOR]

The effect of surface roughness on the interfacial contact resistance (ICR) and the corrosion behavior of 446 stainless steel in simulated anode environments for proton exchange membrane fuel cell (PEMFC) (i.e., 0.5 mol L−1 H2SO4 + 2 ppm F− and 5 × 10−4 mol L−1 H2SO4 + 0.1 ppm F− bubbled with hydrogen gas at 80 °C) was investigated by means of atomic force microscopy, potentiodynamic polarization, electrochemical impedance spectroscopy and ICR test. The surface roughness (Ra) produced by mechanical grinding increases noticeably with the decrease of sandpaper grit size from 1000# to 240#. 446 stainless steel shows the active state under free corrosion conditions in the two test solutions and the passive state at the typical anode working potential of PEMFC after the activation-passivation transition. The corrosion resistance decreases with the increase of roughness in both solutions. The corrosion product films formed in the solution with lower acidity are more protective, leading to the appearance of the diffusion process. The enlargement of surface roughness results in the gradual reduction of ICR, but the acceleration of active and passive dissolutions. [ABSTRACT FROM AUTHOR]