Vol. 42, Iss. 3

This study systematically investigated the effects of three types of surface modification techniques—chemical treatment, thermal treatment, and electrochemical treatment—on the adhesion and corrosion resistance of SiO\(_2\) protective coatings on TC4 titanium alloy substrates. Through multi-scale characterization, it was found that substrate roughness is positively correlated with coating adhesion. C\(_8\)HO\(_3\)Si chemical treatment (roughness 63 \(\mu\)m) and MAO treatment (62 \(\mu\)m) achieved the highest adhesion strengths of 8.01 MPa and 7.91 MPa, respectively, with both exhibiting 100% Type B interface failure (cohesive failure within the coating), indicating that the interface bonding strength exceeds the coating’s inherent strength. In contrast, H\(_2\)O\(_2\) treatment (roughness 16 \(\mu\)m) exhibited the lowest adhesion (2.57 MPa). Electrochemical testing revealed that C\(_8\)HO\(_3\)Si-treated samples had the most positive corrosion potential (-0.087 V), lowest corrosion current (4.3 nA/cm\(^2\)), and widest passivation range (0.131 V), demonstrating the best corrosion resistance. MAO treatment increased surface hardness to 417 HV (uncoated substrate: 204 HV), improving corrosion resistance by 51.08%. After 10 days of salt spray testing, the impedance of the C\(_8\)HO\(_3\)Si and MAO coating systems remained above 1.0 \(\mathrm{\times}\) 10\(^9\) \(\Omega\)·cm\(^2\), significantly outperforming FCS treatment (corrosion current: 30.7 nA/cm\(^2\)). XRD confirmed that MAO forms highly crystalline rutile-type TiO\(_2\) (characteristic peaks at 27.5\(\mathrm{{}^\circ}\) and 36.1\(\mathrm{{}^\circ}\)), while FCS generates a CaTiO\(_3\)/hydroxyapatite composite layer (peaks at 33.2\(\mathrm{{}^\circ}\) and 25.9\(\mathrm{{}^\circ}\)). The dense phase structure is key to enhancing protective performance. The synergistic optimization of substrate roughness, interfacial bonding, and passivation capability achieved by combining C\(_8\)HO\(_3\)Si chemical treatment with MAO electrochemical treatment provides an effective solution for the application of titanium alloy protective coatings in harsh environments.

The advancement of polar marine engineering has led to increasing demands on the performance of metal coatings. This paper aims to enhance the corrosion resistance of metal surface coatings by modifying epoxy resin using thiazole-graphene oxide (AMT-GO) and a curing agent. Combining coating processes and curing techniques, the metal surface coating is successfully applied. Through various types of testing, the improved corrosion resistance of the organic coating (AMT-GO/EP) is evaluated. The research results show that in different tests, the AMT-GO/EP coating exhibits fewer than 10 chemical composition shift peaks. Adhesion decreases by only 17.79%. At room temperature, the maximum corrosion potential is -0.27 V, and the minimum corrosion current density is -8.56 A/cm\(^2\). At room temperature in saltwater, the potential positive shift was only 0.05V, and the current density was also lower than that of other coatings. The coating exhibited the strongest resistance performance in ultra-low-temperature saltwater.

Due to the harsh marine tidal zone environment characterized by prolonged exposure to wave impact, high salinity, alternating wet and dry conditions, solar radiation, and abundant microbial attachment, the selection of coatings and repair technologies has become a key focus in the research of corrosion-resistant and erosion-resistant coating systems for offshore wind power equipment. In terms of an integrated corrosion-resistant and erosion-resistant coating system, this paper designs a coating system for the embedded anchor bolts and concrete foundation caissons of offshore wind turbines, along with methods for characterizing their performance. In selecting corrosion-resistant materials for the coating system, acrylic polymers were prepared, and the optimal addition ratio was determined through multiple rounds of experiments. Additionally, using WC-Co hard alloy as raw material, a WC-12Co composite coating was prepared via plasma spraying to form the erosion-resistant coating layer of the surface coating system. For the repair of existing worn offshore wind turbine steel components, laser cladding technology was introduced, combined with epoxy resin asphalt paint materials to prepare a cladding layer in the worn areas. The average mass loss of each component cladding layer under a 90° erosion angle was only approximately 20% of the substrate, demonstrating excellent erosion resistance performance.