Titanium and titanium alloy coatings have high potential for applications in several industrial fields such as aerospace, bio-medical and chemical industries. Its eligibility for each single application depends on physical, chemical and mechanical properties. Cold spray as a deposition technique for titanium coating is growing because there is no need for vacuum or protective atmospheres. The properties of cold spray titanium coatings can be tailored by controlling and optimizing the process parameters. In this study the effect of the gas pressure and temperature on the deposition process and the coatings properties were examined. Cold spray CP-titanium coatings were produced using nitrogen as propellant gas at different gas pressures (from 2.0 MPa to 3.5 MPa) and temperatures (from 400°C to 800°C). Morphology and the microstructure of the CP titanium powder and coatings were studied by scanning electron microscope (SEM) and light optical microscope (LOM). Micro-hardness measurements and oxygen and nitrogen contents of titanium powder and the coatings were performed. As a final step, residual stress analysis of deposits were measured by means of X-ray diffraction.

Copper particles with median diameter 15.2 micrometres were cold sprayed onto a polished aluminium 1139 substrate. Under the spray conditions used, deep embedment of the copper particles occurred. The as-sprayed copper particles were dissected using a focussed ion beam (FIB), and their microstructure investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). At the crater wall an intense shear zone developed due to sliding of copper past aluminium. Evidence of melting is presented.