Abstract
Abstract
The authors have studied the effect of titanium and chromium diffusion coatings on corrosion resistance of sintered iron in solutions of acids and salts. The samples of 85% density were obtained from powdered iron by static pressing in press dies and sintering in vacuum. The diffusion coatings were applied in molten lead with titanium and chromium additives at the temperature of 1100°C and 2 hours exposure time. Microstructure of the samples was then explored by the optical metallography method. The content of elements in the coatings was measured using energy dispersive X-ray microanalysis. Studies of corrosion resistance of the samples in solutions of acids and salts were conducted by the gravimetric method. Corrosion resistance was also evaluated by time to the first corrosion foci emerging and the area of corrosion damage. Diffusion titanium and chromium coatings have ensured higher corrosion resistance of sintered iron in all the aggressive media studied. Chromizing is the most efficient for protecting sintered iron in solutions of sulphuric and nitric acids, as well as in media containing acetic acid and hydrogen peroxide. Meanwhile, titanizing is the most efficient for protecting sintered iron in sea water.