Magnesium coatings for lighter spaceships
Magnesium and its alloys have many applications in multiple industrial fields. In the automotive, the aviation and in the space industry, the demand is constantly rising. Magnesium alloys are susceptible to abrasion and corrosion and need to be coated for protection. Innovative coating processes have been developed like plasma enhanced chemical vapour deposition (PECVD) that deposits thin protective films on the magnesium substrates. The NANOMAG project has optimised these recent coating techniques and, for the most promising ones, has determined and compared the levels of their environmental impact by means of life cycle assessment (LCA). LCA, a widespread method, in general determines the environmental impact generated throughout a product's life cycle - from resource procurement through manufacturing, transportation, use, maintenance, recovery, recycling, to disposal. Three coating processes have been assessed; the PECDV technique, the ANOMAG and the KERONITE. The last two are trademarked industrial processes that also offer hard, wear-resistant surfaces on light alloys. Project partners first compared the laboratory developed PECDV with the industrial ANOMAG technique. The LCA comparison showed that the plasma deposition technique has lower environmental impact than the ANOMAG. The cleaner and more environmentally friendly plasma process will be further developed and optimised for future industrial applications. LCA comparison between the two industrial processes, ANOMAG and KERONITE, on a 1m2 of magnesium coated with a 20µm layer, at first glance shows that KERONITE has higher impact. However, when corrosion protective properties and other environmental impact parameters are taken into account, the results are rendered inconclusive. Nevertheless, these clean, highly efficient and economical processes bring the automotive and aviation industries much closer to substantially reducing fuel consumption, and the space industry to manufacturing lighter launchers.