The traditional importance of hard chromium electroplating in surface engineering is recognised and the key features of this well-established technology are summarised. Despite the high hardness, corrosion protection and wear resistance of chromium electrodeposits, a number of alternative coating compositions and application techniques have been developed for specific applications in tribology. Environmental challenges associated with hard chromium electroplating are highlighted and the need to develop and evaluate alternative coatings is stressed. Key examples of the alternative coatings are described, including their method of application, microstructure and tribological performance in controlled service environments. Research needs requiring rapid development are highlighted. A summary is given of the most competitive coatings and those having the potential to match the performance of hard chromium in selected applications are identified.

A robust superhydrophobic coating based on Ni/WS₂was fabricated successfully through a simple one-step electrodeposition process. This metal-caramic composite coating showed excellent self-cleaning and corrosion resistance properties.

The mechanical properties of superhydrophobic surfaces based on nickel composite coatings was enhanced by co-deposition of tungsten carbide. After modified by stearic acid, the surfaces showed excellent water-repellence and abrasive resistance.

A novel but simple path for the preparation of superhydrophobic and superhydrophilic coatings has been demonstrated via a recently developed technology, namely suspension high velocity oxy-fuel spraying. Potential uses for robust superhydrophobic coatings include antifouling applications such as aeroplane wings, ship hulls, offshore wind turbine blades, or the above-deck structures on ice breaker vessels. Several fabrication techniques have been reported for preparing inorganic superhydrophobic surfaces, but existing coatings either lack the necessary robustness for engineering applications and/or their deposition methods are not suitable for industrial scale-up. In this work, the industrially established HVOF coating process was adapted to use a liquid suspension of commercially available nano-particles (titania—TiO₂, and hexagonal boron nitride—h-BN) as feedstock to produce nanostructured suspension HVOF TiO₂/h-BN coatings for the first time on stainless steel. Results indicate that agglomerates in the nano-feedstock can be dispersed by h-BN due to poor mutual wettability between h-BN and molten TiO₂. It also inhibits the anatase-to-rutile transformation of TiO₂ during coating deposition by inhibiting sintering of TiO₂ in the HVOF flame. The resultant coating becomes superhydrophobic when the addition of h-BN reaches 10 wt% due to the presence of hierarchical nano-texture on the surface. The superhydrophobicity (contact angle of 163–170°) is maintained over a long period of time (>13 months, test still ongoing) and remains stable after exposure to light and tape test. A potential route for industrial preparation of robust water-repellent coatings is therefore highlighted by the study.