DSC Analysis of Cold-Sprayed Copper Coatings

In this study copper coatings were deposited by cold spraying, under different spraying conditions. Microstructure of the coatings was investigated by optical and scanning electron microscopy. Additionally, differential scanning calorimetry (DSC) and thermal gravimetric analysis were used to examine the quality of the coatings, especially with regards to the extent of the bonded area between the particles. As shown in SEM results, the electrolytic-powder exhibited a much higher population of internal boundaries, as compared to the spherical powder sample. This means that even for identical values of FBA for both types of sample, the electrolytic sample would contain a larger amount of non-bonded areas per unit volume. The results of DSC indicated exothermic reactions at certain temperatures that maybe related to spray conditions and microstructural properties. The samples sprayed at higher pressures, have lower non bonded areas. TGA also has confirmed this result. Moreover, it can be concluded, the spherical powders cause more compact coatings. So, thermal analysis can be utilized reliably to examine the fraction of bonded areas in cold-sprayed deposits.