Evaluation of the corrosion resistance of iron boride coatings obtained by paste boriding process

An evaluation of corrosion resistance of boride coatings in AISI 304 steel was carried out. Formation of iron boride layers (FeB and Fe2B) at the material surface was obtained by paste boriding process. Boron paste thicknesses of 4 and 5 mm were applied to the steel surface. A thermochemical treatment, for each boron potential, was carried out at temperatures of 1173, 1223 and 1273 K; with exposure times of 4 and 6 h. Corrosion resistance of the borided samples was evaluated by the electrochemical techniques of open circuit and polarization resistance with a 0.1 M solution of NaCl. Dependence between the polarization resistance and the experimental parameters is observed. The results show that the corrosion resistance is maximized with a treatment time of 4 h and a boron paste thickness of 4 mm.