The electrochemical corrosion behavior of magnetron sputtered nanocrystalline (NC) 304 stainless steel (ss) thin film as well as that of the conventional rolled coarse crystalline (CC) 304ss has been studied in 0.05 M H₂SO₄ + 0.2 M NaCl solution using electrochemical and imaging techniques. The experimental results indicate that the NC thin film exhibits superior corrosion resistance compared to CC 304ss. The semi-conductor properties of the passive films on both materials as predicted by the Mott-Schottky equation show that the donor and acceptor concentrations of the passive film on NC thin film are higher than that of CC 304ss, while diffusion coefficients of carriers are lower than for CC 304ss. The composition of the passive film on NC thin film measured by X-ray photoelectron spectroscopy (XPS) has a higher the ratio of Cr oxides to Fe oxides. In-situ AFM observation found that the growth rate of the passive film on NC thin film was significantly faster than that of CC 304ss. The higher content of Cr oxides and better passivation ability of the passive film enhance the corrosion resistance of the nanocrystalline specimen together.

The corrosion behavior of 2A02 Al alloy under 4 mg/cm² NaCl deposition at different temperatures (from 30 to 80 °C) has been studied. This corrosion behavior was researched using mass-gain, scanning electron microscopy-SEM, laser scanning confocal microscopy-LSCM, X-ray photoelectron spectroscopy-XPS and other techniques. The results showed and revealed that the corrosion was maximal at 60 °C after 200 h of exposure. The increase of temperature not only affected the solubility of oxygen gas in the thin film, but also promoted the transport of ions (such as Cl⁻), and the formation of protective AlO(OH), which further affects the corrosion speed.

A rapid degradation of wet adhesion is the key factor controlling coating lifetime, for the organic coatings under marine hydrostatic pressure. The mathematical models of wet adhesion have been studied by Grey System Theory (GST). Grey models (GM) (1, 1) of epoxy varnish (EV) coating/steel and epoxy glass flake (EGF) coating/steel have been established, and a lifetime prediction formula has been proposed on the basis of these models. The precision assessments indicate that the established models are accurate, and the prediction formula is capable of making precise lifetime forecasting of the coatings.

A concept for prediction of organic coatings, based on the alternating hydrostatic pressure (AHP) accelerated tests, has been presented. An AHP accelerated test with different pressure values has been employed to evaluate coating degradation. And a back-propagation artificial neural network (BP-ANN) has been established to predict the service property and the service lifetime of coatings. The pressure value (P), immersion time (t) and service property (impedance modulus |Z|) are utilized as the parameters of the network. The average accuracies of the predicted service property and immersion time by the established network are 98.6% and 84.8%, respectively. The combination of accelerated test and prediction method by BP-ANN is promising to evaluate and predict coating property used in deep sea.

The corrosion behavior of Ti60 alloy covered with a solid NaCl deposit in wet oxygen flow at 600 °C has been studied further by SEM, EDX, XPS, XRD, TEM and EPMA analysis. The results show that solid NaCl and H₂O react with Ti oxides, which destroyed the Ti oxide scale to yield the non-protective Na₄Ti₅O₁₂ and other volatile species. The resulting corrosion product scale was multilayered and contained abundant rapid diffusion channels leading to the fast diffusion which improved the corrosion rate. A possible mechanism has been proposed for the NaCl-covered Ti60 alloy, based on the experimental results.

The corrosion behavior of pure Ti under a solid NaCl deposit in a wet O₂ flow at 600 °C has been studied. The results showed that the corrosion rate was greatly accelerated by solid NaCl, which destroyed the compact and protective TiO₂ scale to yield non-protective N₄Ti₅O₁₂ and other products. Detailed scanning electron microscopy (SEM) equipped with an energy dispersive spectrometer (EDX), and X-ray diffraction (XRD) analysis showed that, during the corrosion process, the metal (Ti) diffused outward rapidly and reacted with the wet O₂ to form a thick and porous corrosion products scale. The electrochemical reaction was also observed during the whole corrosion process at 600 °C, which further accelerated the corrosion rate. A possible mechanism has been proposed for pure Ti covered with a solid NaCl deposit in wet O₂ at 600 °C, based on the experimental results.