Cold Gas Spraying is a new coating technique, in which the formation of dense, tightly bonded coatings occurs only due to the kinetic energy of high velocity particles of the spray powder. These particles are still in the solid state as they impinge on the substrate. Adiabatic heating after impingement can cause local shear instabilities and jet formation. The local microstructure is strongly dependant on local stress state and temperature rise. A variety of different microstructures is observed by TEM. The results are compared with modelling of the spray process.