Bonding phenomena studies of cold sprayed coatings at the interfaces

The microstructures at the interfaces of cold-sprayed coatings on were investigated by TEM. In the case of Al coatings on Fe substrate, the collision of even relatively soft particles could generate a thin and amorphous Al-Fe intermixed layer that provides fully coverage along the interface (so called, amorphization). Also, a part of this amorphous layer came off in the original layer, which embedded in Al coatings. In contrast, thick Fe-Al intermixed zone was observed at the interface of Fe coatings on Al substrate due to the hard Fe particlesĄŻ impact and the soft substrate combination. Therefore, the adhesive strength of cold sprayed coatings was attributed to these bonding phenomena.