Influence of annealing treatment on microstructure and properties of cold sprayed stainless steel coatings

304 stainless steel coatings had been deposited on carbon-steel substrate by cold spray technique, vacuum annealing treatment was applied to the coatings with different temperatures, and the influence of annealing treatment on the microstructure and electrochemical behavior of the coatings in 3.5% NaCl were analyzed. The results indicated that, the cold sprayed coating was constituted by the flattened particles, and the interfaces were clearly observed between the deposited particles. It was also found that annealing treatment led to the recovery and recrystallization of the elongated grains in the as-sprayed coatings with the increase of annealing temperature. When the annealing temperature achieved to 950 ？ C, the interface of particles was disappeared and the coating s structure was made of new recrystallization austenite grains. Annealing treatment increased the potential volts, and reduced the corrosion rate with the increase of annealing temperature. The electrical corrosion morphology indicated that, the corrosion was firstly at the distortion area and the crevice corrosion mechanism played an important part. Based on these results, processes active during annealing treatment are kinetically dependent and strongly influenced by the annealing treatment temperature.