Porosity in cold sprayed titanium walls and straight corners

Cold spray is a solid-state deposition process that is well suited to oxygen-sensitive materials such as titanium. Titanium can be cold sprayed at rates of kilograms per hour without the need for a protective atmosphere. Typically, nearly 100% deposition efficiency results due to ready adiabatic shearing and propensity to bonding of titanium particles upon impact. However, deformation and flattening of titanium particles are more challenging with the result that some porosity can remain in the deposit. Incomplete bonding over the interfacial particle area can also result in fine voids. Porosity is also a function of location within the spray pass and is a function of robot tool path. Understanding these interrelationships is essential to producing titanium with useful properties.