The preparation of Ti coatings on mild steel can both effectively improve the corrosion resistance of the substrate and reduce the application cost of Ti, which is an effective measure to improve the service performance of mild steel in the marine environment. Plasma cladding technology is an efficient method for preparing metal coatings, and the type of powder is a key process parameter for coating preparation. In this work, high-performance Ti coatings are prepared on the surface of mild steel by plasma cladding technology, and the effects of different particle sizes and shapes of Ti powders on the surface morphology, microstructure and properties of the coatings are studied. The results show that powder particle size and sphericity are the key factors affecting the morphology, structure and service performance of Ti coatings. After 1000 h of salt spray test, the spherical powder cladding coatings only suffer slight corrosion, while the irregular shape powder coating is more severely corroded. Powder cladding with moderate powder particle size and good sphericity have a smoother coating and fewer defects. Ti powders with different particle sizes and shapes all have the diffusion of Fe element during the cladding process. The surface of Ti coating prepared by spherical powder are dominated by α-Ti and Fe_0.2Ti_0.8 phases, while the surface of Ti coating prepared by irregular shape powder is dominated by FeTi and Ti₂Fe. The interface between the coating and the substrate shows metallurgical bonding, and the increase in Ti-Fe brittle phase will deteriorate the mechanical properties and corrosion resistance of the coating. The shear strength of coatings prepared from spherical Ti powders of 75–150 μm can reach 105.18 MPa, the corrosion potential is the most positive (−0.2206 V), and the self-corrosion current density is the lowest (6.220 × 10⁻⁸ A/cm²).

Titanium and its alloys are well-suited for marine engineering owing to their high specific strength and superior corrosion resistance. However, their high cost remains a key barrier to widespread marine application. Titanium/steel (Ti/Fe) dissimilar materials provide a promising solution by integrating titanium’s corrosion resistance with the high strength of steel, thereby significantly reducing costs. This review systematically assesses the potential preparation strategies for Ti/Fe dissimilar materials, such as explosive welding, rolling, high-energy beam cladding, and cold spray, to meet the large-scale application requirements in marine engineering. Advanced welding techniques for joining Ti/Fe joints are also discussed. The advantages and issues of Ni, Cu, Fe, and Al interlayers suitable for marine engineering applications in inhibiting Fe-Ti IMCs are introduced, with a focus on their potential in promoting the development of economically efficient ocean engineering. A comprehensive evaluation is conducted on the performance of Ti/Fe dissimilar materials, particularly their corrosion resistance and fatigue resistance in marine environments. This review aims to provide a reference for the theoretical research, preparation strategies, and application expansion of low-cost Ti/Fe dissimilar materials in marine engineering.

The fouling behavior of a steam generator (SG) tube was investigated at different positions after 500 h of immersion in high-temperature water. A triple-layer structure of fouling appeared at both the crevice position and the free span position, namely, the large, dispersedly distributed deposition layer on the top; the small and faceted outer layer; and the relatively continuous inner layer. There was no obvious positional effect on the thickness of the inner layer. However, in the crevice position, the density of the deposited particle and the thickness of the outer layer was much higher than those of the free span position. The tube support plate (TSP) made of 410 stainless steel contributed significantly to the fouling behavior of the SG tube in the crevice between the SG tube and the TSP.