Search

Different microstructures of the Al2O3 plasma electrolytic oxidation (PEO) films were obtained by controlling the frequency of applied high-frequency square voltage waveform (HFSVW) under different transient self-feedback control (TSFC). The morphology and compactness of the PEO films were characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Experimental results indicated that uniform, compact, small-grained TSFC PEO films can be produced by applying high-frequency HFSVWs.

A composite film was prepared by depositing layers of plasma electrolysis oxidation (PEO) film and self-assembled nanoparticle (SANP) film on a Mg-Gd-Y alloy. The electrochemical impedance spectroscopy (EIS) results showed that the structure of the PEO + thin SANP layers greatly increased the corrosion protection of the composite film. In addition, two water diffusion coefficients (D) of the composite film were obtained using EIS and Kalnin's model. The D values indicated the composite film had a good barrier property against water.

An interlayer film between a magnesium alloy substrate (MAS) and electromagnetic wave absorption coatings (EWACs) has been produced by micro-arc oxidation (MAO) method. A new voltage mode has been developed for use in the MAO technique. The corrosion resistance of MAS has been investigated in 3.5 wt% NaCl solution. The results show that the MAO interlayer not only delays interaction of chloride electrolyte with MAS but also changes corrosion behavior of the metal substrate. The film restricts propagation of filiform corrosion at the coating/substrate interface and simultaneously eliminates galvanic couples by separating absorbents in the EWAC from the MAS.

A composite film was prepared by depositing layers of plasma electrolysis oxidation (PEO) film and self-assembled nanoparticle (SANP) film on a Mg-Gd-Y alloy. The electrochemical impedance spectroscopy (EIS) results showed that the structure of the PEO + thin SANP layers greatly increased the corrosion protection of the composite film. In addition, two water diffusion coefficients (D) of the composite film were obtained using EIS and Kalnin's model. The Dvalues indicated the composite film had a good barrier property against water.

Different microstructures of the Al2O3plasma electrolytic oxidation (PEO) films were obtained by controlling the frequency of applied high-frequency square voltage waveform (HFSVW) under different transient self-feedback control (TSFC). The morphology and compactness of the PEO films were characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Experimental results indicated that uniform, compact, small-grained TSFC PEO films can be produced by applying high-frequency HFSVWs.

An interlayer film between a magnesium alloy substrate (MAS) and electromagnetic wave absorption coatings (EWACs) has been produced by micro-arc oxidation (MAO) method. A new voltage mode has been developed for use in the MAO technique. The corrosion resistance of MAS has been investigated in 3.5 wt% NaCl solution. The results show that the MAO interlayer not only delays interaction of chloride electrolyte with MAS but also changes corrosion behavior of the metal substrate. The film restricts propagation of filiform corrosion at the coating/substrate interface and simultaneously eliminates galvanic couples by separating absorbents in the EWAC from the MAS.