Abstract 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 low porosity and oxide-free CRA coatings. This paper describes the corrosion performance of Ni-based Alloy 625 following cold spraying onto steel substrates both as-sprayed and following heat treatment. Microstructures and oxygen content of powders and coatings were investigated, and coating microhardness and strength were determined in both as-sprayed and post treated conditions. Mercury intrusion was used to measure the interconnected porosity in the as-deposited and post-treated coatings. Finally, the corrosion behaviour of the sprayed and post-treated coatings was measured using a standard test (ASTM B117-07a).