Cold spraying operates at fairly low process temperatures below the melting point of most metallic materials. Typically, nitrogen or, in some cases, helium are used as process gases, and guarantee that the spray material only to minimum extent is exposed to environmental oxygen. Thus, side reactions, as obtained in thermal spraying and in the case of metallic materials leading to oxidation, can be avoided, making the method most suitable to retain properties of the feedstock material. By comparing the mechanical properties of cold sprayed and thermally sprayed coatings, quite a number of influences have to be distinguished. The type of defects, being present as micro pores or additional phases, and their distribution already effects different materials responses under compressive, tensile or shear loads. Moreover, the dislocation densities attained under the thermo-mechanical treatments during coating formation - and thus respective work hardening or annealing conditions - have to be considered.

Based on results from tensile tests and hardness measurements, influences by different types of defects obtained in cold spraying and in thermal spraying can be distinguished. The investigations demonstrate for the example of copper, that mechanical properties similar to work hardened bulk material can be already obtained in the as sprayed state by using nitrogen as process gas under very well tuned spray conditions. By additional heat treatments, the attainable strain to failure can be enhanced to about 40 % of elongation, being very similar to that of soft annealed, cold rolled copper. Present results also demonstrate that these concepts can be transferred to quite a variety of metallic spray materials. Thus, a more general tool to predict coating performance attainable in cold spraying can be provided.