Novel Environmentally-Friendly Coatings for Aerospace Alloys

摘要

In the present study, coatings of aluminium, zinc and combinations of aluminium-zinc and zinc-nickel were applied to steel substrates using the cold gas spray process. The effects of powder morphology and impact velocity, as determined by gas temperature and pressure, on the uniformity of the coatings were investigated. The through coating microstructure and composition were examined using scanning electron microscopy to determine the elemental distribution and the nature and extent of porosity. Work continues with an investigation of substrate condition and spray parameters on deformation and bonding. Significant plastic deformation of metal grains was evident. Further, it was revealed that the uniformity and compactness of the coatings are directly associated with the shape and size of the powders, and the gas pressure and temperature. The performance of the coatings is currently being evaluated and compared with ion vapour deposited and electrodeposited coatings.