OPTIMIZATION OF THE CHROMIUM CONTENT OF POWDER WIRES OF THE Fe-Cr-C AND Fe-Cr-B SYSTEMS ACCORDING TO THE CORROSION RESISTANCE OF ELECTRIC-ARC COATINGS

摘要

We study electric-arc coatings of the Fe-Cr-C and Fe-Cr-B systems. It is shown that chromium content of 12 wt.% is insufficient to guarantee higher corrosion resistance of the coatings in neutral aqueous solutions (as compared with steels) caused by the formation of chromium-based oxides, carbides, and borides. Therefore, the indicated chromium content of the compounds should be taken into account and compensated in finding the chemical composition of powder wires. Its unjustified increase is not reasonable because powder wires are characterized by filling coefficients restricting the possibility of their filling with alloying elements. Therefore, the content of each alloying element in the charge of powder wires should be well justified and determined. For this purpose, we propose to use the relations taking into account the nonlinear distribution of chromium in the lamellas of the coatings caused by their high microheterogeneity and the depletion of their solid solution of the indicated element as a result of the formation of oxides, carbides, and borides on its base.