Abstract
Fe-Cr(-Mo) alloy coatings were thermal sprayed by different processes of LPPS, HVOF and HPS. The as-sprayed coating by LPPS is perfectly amorphous and coatings by other processes contain partly crystalline phases. The amorphous phases crystallize at 773 K or more and shows a high hardness of about 1000 to 1400 DPN just after crystallization. The anodic polarization curves of the coatings shift from active to passive state in 1N H2SO4 and 1N HCl solutions. The coatings obtained by LPPS indicate the lowest active and passive current densities and possess the best corrosion resistance. The corrosion resistance of the coatings obtained by other processes are better than a SUS316L stainless steel coating. The LPPS coating of Fe-Cr-C-P alloy is not attacked on immersion test in 6% FeCl3·6H2O solution containing 0.05N HCl at the corrosion potential, while large pit corrosion is developed in a SUS316L stainless steel sheet.
