Corrosion properties of advanced cold-sprayed tantalum and titanium coatings

Cold spray technologies are developing and the main trend is to increase gas pressure and preheating temperatures and this way, improve the coating qualities and performances. One advantage of cold spraying is its capability to produce dense and tight coating structures acting as corrosion barrier coatings. Advanced cold spray technologies open possibilities to prepare protective coatings for even harsher corrosion conditions than it has up to now been done. This study focusses on the corrosion properties of advanced cold-sprayed Ta and Ti coatings. In addition to structural characteristics, their corrosion behaviours have been studied under various conditions, by means of polarization and electrochemical impedance spectroscopy testing in 0.5 M H2SO4 solution and of Corrodkote corrosion testing according to the ASTM B380 standard. In addition to this, cavitation resistance has been analysed as an indicator of cohesive strength of the coatings. Cold-sprayed Ti coatings owned reasonable corrosion resistance, whereas cold-sprayed Ta coatings showed superior corrosion protection in all corrosive conditions measured.