Preliminary study of cold spraying using radial supersonic nozzle

Abstract

The paper deals with the problem of coating production on internal pipe surfaces by the cold spraying. It reports on a new assembly design with a radial supersonic nozzle that greatly facilitates the application of aluminium, copper and nickel coatings onto internal pipe surfaces. Visualisation and Pitot tube measurements of the airflow produced by the nozzle assembly assist to predict the range of internal pipe diameters, in which the pipes could be successfully coated from the inside using the designed instrument. The velocity of aluminium particles has been measured at the exit from the radial nozzle and calculated the particle velocities under the actual cold spray conditions. Finally, the mass and energy consumption characteristics of the process and the deposition efficiencies achievable under typical experimental conditions have been calculated. Those calculations have allowed us to evaluate the cost of potential introduction of the cold spray process into pipe production.

A perspective review on the bonding mechanisms in cold gas dynamic spray

“…In the cold spray processes, the velocity of the particles dictates the deposition process as well as the coating properties for given materials [54]. The impact velocity and the critical velocity of the particles depend on the powder properties [55] and cold spray conditions [56], particle size and shape [57], particle temperature [58], carrier gas species [59,60], heating temperature [61] and nozzle geometry [62,63]. The nozzle geometry and the nature of feedstock powders significantly influence the particle stream and therefore the achievable final temperature and sprayed particles velocity [64,65].…”