Effect of microstructure on the corrosion resistance of coatings by extreme high speed laser cladding

•Ultrafine dendrites with sizes of 700 nm were achieved under a 100 m/min cladding speed by extreme high speed laser cladding (EHLA).•The uniformly distributed dendrite sizes and compositions contribute to the formation of a dense passive film.•A compositional difference in the Cr content will lead to a preferential corrosion at the junction of dendrites and inter-dendritic regions.