Corrosion of Ti Coating Prepared by Modified HVOF Process

Abstract Titanium exhibits very good corrosion resistance property because of the formation of very dense oxide coating. Especially the good corrosion against Cl- solution for titanium material makes it wide applications in sea industry. It is very difficult to deposit titanium coating under atmospheric condition due to the strong affinity with oxygen and nitrogen especially in high temperature plume. Except the expensive LPPS process, much attention has been paid to the newly developed cold spraying. Unfortunately the stringent requirement for the starting power and low production efficiency limit the application of the cold spraying. A modified HVOF process was developed by reducing the outlet diameter of chamber and by directly introducing water into chamber, therefore lower plume temperature and higher chamber pressure than conventional HVOF process can be achieved. Attempts to deposit Titanium coating were carried out, and immersion of Titanium coated A3 steel into artificial seawater was performed in order to evaluate the density of as-sprayed Titanium coating. The results showed that dense Titanium coating could be obtained after parameter optimization and very few corrosion spot was observed on the surface of Titanium coated A3 steel after immersion into artificial seawater for 120 h.