2013 Volume 50 Issue 1 Pages 2-6
Ti coatings for anti-corrosion coating were prepared via cold spray process, and their microstructures, adhesion morphology of feedstock powders, and influence of post treatment on mechanical properties were evaluated. The Ti coatings were fabricated using Ti powder with the size of -45um onto mild steel substrate with N2 carrier gas, and heat treated at 1093K and compressed with the force range of 98-1176 MPa. Porosity of the cold sprayed coating is 5.4 %. The coating adheres to the substrate metallurgically, however, pores with the size of approximately 10um exist at coating/substrate boundary. After the heat treatment, the porosity decreases to 4.1 %, and bond strength of the coating increases from 13 MPa to more than 70 MPa. Density of the coating enhances with increasing the compressive force in the both case of before and after the heat treatment. However, in the case of after heat treatment, the bond strength decreases with increasing the compressive force due to occurring of cracks at the coating/substrate boundary, and it is considered that the starting points of the cracking are the pores at the boundary. Therefore, it is expected that prevention of the pores might be effective for improvement of the bond strength of the compressed coatings.
