Production of Corrosion Resistant Deposits by Cold Gas Dynamic Spray

Despite much research effort and many application development studies, corrosion resistant alloy (CRA) coatings, prepared by thermal spraying still provide greatly inferior corrosion resistance when compared to parent material of the same composition, due to a network of oxides and pores in the coatings. However, the recent development of Cold Gas Dynamic Spray (CGDS) technology has made possible the deposition of virtually pore-free and oxide-free CRA coatings. This paper describes work undertaken on parameter development, which includes the use of spray particle diagnostics, for the deposition of CRA by cold spraying. All coatings were deposited onto steel substrates and were evaluated in terms of microstructure, hardness and oxide/porosity content, adhesive strength and corrosion resistance. The data generated were also benchmarked against data relating to conventional thermal spray coating properties (particularly HVOF spraying).