Sandwich-structured C₃N₄/Au/CdZnS photocatalyst.

In this work, the photo-catalytic activity of TiO₂ is considerably enhanced via sensitization with CdIn₂S₄, and its application for protecting Q235 from corrosion in splash zones is examined. TiO₂ nanotube arrays (NTAs) are prepared on a flat Ti substrate via two-step anodization. CdIn2S4 is deposited on the surface of TiO₂ NTAs by hydrothermal reaction. TiO₂ NTAs with enormous specific surface areas and large-diameter hollow nanostructures are found to benefit the immobilization of CdIn₂S₄. As a narrow band gap semiconductor, CdIn₂S₄ is able to extend the light absorption range of TiO₂, and the construction of an n–n type hetero-junction accelerates the separation of carriers. Strong solar light, which accelerates the corrosion of Q235 in the splash zone area, is converted into the necessary condition for protecting Q235 from corrosion. In this work, TiO₂ is sensitized with MoS₂ microspheres (MoS₂/TiO₂ nanocomposites), which were prepared on a flat Ti substrate via a two-step anodization and hydrothermal method, sequentially.

Corrosion behavior of Mg‐5Y‐1.5Nd alloy was investigated after heat treatment. The microstructure and precipitation were studied by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The weight loss rates of different samples were arranged as T6‐24 h>T6‐6 h>T6‐14 h>as‐cast>T4. The open circuit potential (OCP) showed that T4 sample had a more positive potential than that of other samples. The potentiodynamic polarization curves showed that the T6‐24 h sample had the highest corrosion current density of 245.362 μ A·cm ⁻² , whereas the T4 sample had the lowest at 52.164 μ A·cm ⁻² . The EIS results confirmed that the heat treatment reduced the corrosion resistance for Mg‐5Y‐1.5Nd alloy, because the precipitations acted as the cathode of electrochemical reactions to accelerate the corrosion process. The corrosion rates of different samples were mainly determined by the amount and distribution of the precipitations. The precipitations played dual roles that depended on the amount and distribution. The presence of the phase in the alloys could deteriorate the corrosion performance as it could act as an effective galvanic cathode. Otherwise, a fine and homogeneous phase appeared to be a better anticorrosion barrier.