Denseness and Adhesion of Low-Pressure Cold Spray Coating to Corroded Steel Bridges

High-strength bolt attachment parts of steel bridges are prone to corrosion at an early stage, and blast nozzles and power tools cannot be inserted due to the structural shape during repairs, and there are many cases where rust remains partially. To solve such a problem, the Cold Spray technology, which uses a powder that mixes zinc and alumina, exhibits corrosion resistance by depositing a film even if rust remains. In this paper, first the anticorrosion mechanism on the residual rust was examined by focusing on the permeation prevention of the corrosion factor of the Cold Spray anticorrosion film and the adhesion of the residual rust boundary. Findings indicate that the Cold Spray anticorrosion film exhibits a porosity approximately one-tenth that of films engendered via the thermal spraying method, thereby constituting a denser film with heightened environmental barrier attributes. The firm adherence of the Cold Spray anticorrosion film to the residual rust interface is explained by differences in hardness between Cold Spray, residual rust, and zinc. Furthermore, the physical characteristics of zinc undergo modifications influenced by the temperature environment during construction, imparting a plasticity to zinc on uneven rust surfaces.