While twin wire arc spraying, strong dependences are usually noticed between elaboration process parameters and coating properties. Therefore, control is needed for increasing coating performances. The aim of this paper is to investigate the coating properties in relation with in-flight particle characteristics and with the impact modes. Measurements were achieved on iron particles when changing either the current intensity or the air flow rates. In-flight particle characteristics were determined by using the DPV diagnostic system 200 mm from the gun exit and for three different radial locations. The same locations were kept for the impact analysis. Then, the morphology of the splats was evaluated by its flattening and shape factors when the substrate is preheated or not. Finally, the coating properties were characterized in terms of porosity, oxide contents, microhardness and thickness. Through the determination of related interactions, a better knowledge of coating elaboration conditions will lead to improve reliability and properties of the deposits.