Bacterial adhesion and biofilm formation are ubiquitous undesirable phenomena in the marine industry and the medical industry, usually causing economic losses and serious health problems. Numerous efforts have been made to reduce bacterial adhesion and subsequent biofilm formation, most of which are based on the release of toxic biocides from coatings or substrates. In recent years, surface topography has been found to substantially influence the interaction between bacteria and surfaces. This review summarizes previous work dedicated in searching for the relationship between bacterial adhesion and surface topography in the last eight years, as well as the proposed mechanisms by which surface topographic features interact with bacterial cells. Next, various natural and artificial surfaces with bactericidal surface topography along with their bactericidal mechanisms and efficiency are introduced. Finally, the technologies for constructing antibacterial surfaces are briefly summarized.

Cold spray is a solid‐state coating deposition technology developed in the 1980s. In comparison with conventional thermal spray processes, cold spray can retain the original properties of feedstock, prevent the adverse influence on the underlying substrate materials, and produce very thick coatings. Coatings with nanostructure offer the potential for significant improvements in physical and mechanical properties as compared with conventional non‐nanostructured coatings. Cold spray has also demonstrated great capability to produce coatings with nanostructure. This paper is aimed at providing a comprehensive overview of cold‐sprayed metal coatings with nanostructure. A brief introduction of the cold spray technology is provided first. The nanocrystallization phenomenon in the conventional cold‐sprayed metal coatings is then addressed. Thereafter, focus is switched to the microstructure and properties of the cold‐sprayed nanocrystalline metal coatings, and the cold‐sprayed nanomaterial‐reinforced metal matrix composite (MMC) coatings. At the end, summary and future perspectives of the cold spray technology in producing metal coatings with nanostructure are concluded.

Cold sprayed WC-Co metal matrix composite coatings have shown great potential in wear-resistance applications. This work aims to use experimental and numerical methods to clarify the deposition and particle–substrate bonding behavior of a single porous WC-17Co particle onto various substrates. To achieve this objective, porous WC-17Co particles were used as the feedstock; soft Al 2024 (Al alloy) and hard stainless steel 316 (SS) were used as the substrates. The experimental results revealed that brittle WC-Co particles tended to remain intact after depositing on a soft Al alloy substrate, but underwent serious fracture when impacting on a hard SS substrate. Further results indicated that the high energy dissipation and the consequent high stress concentration in the WC-Co particle was the main reason for inducing the particle fracture. In addition, two different mechanical interlocking mechanisms were identified during the WC-Co particle deposition process (namely WC reinforcement interlock and WC-Co particle interlock), dominating the particle-substrate bonding. A soft Al alloy substrate resulted in better interlocking than a hard SS substrate, thereby the corresponding particle bonding ratio was also much higher.

Ermal spray is a surface modification technique where solid, semimolten, or molten feedstock powders from metals to ceramics are propelled towards and deposited onto the target surface to form the coating. So far, a variety of thermal spray processes (e.g., HVOF spray, plasma spray, flame spray, wire arc spray, and cold spray) have been developed and widely applied in a broad range of industries including aerospace, automatic, energy, medical, and marine industries. e thermal sprayed coatings provide effective protection against high temperature, corrosion, erosion, oxidation, wear, chemicals, bacteria, and so on. Particularly, certain thermal spray processes can be utilized as an additive manufacturing technique to fabricate standing-free parts or restore damaged components. Given the aforementioned advantages and great potentials, investigations regarding thermal spray processes are always a focal subject and attracting great attentions from both scientific and industrial communities. is special issue holds 1 review and 9 original research articles. Various thermal spray technologies including cold spray, HVOF spray, arc spray, and plasma spray were used to produce coatings for wear resistance, oxidation resistance, chemical resistance, thermal resistance, and structural applications. Q. Jia and coworkers reported improved oxidationresistance properties of arc-sprayed Al coating onto the Ti substrate through modification reaction. eir study focused