Increasing corrosion resistance of AISI 1010 steel by boride coatings

Abstract

Boriding is the process of coating the metal surface with a ceramic metal boride layer by the diffusion method. Iron borides, one of the metal borides, are called ceramics because they are covalently bonded compounds. Iron boride coatings contain strong Fe-B and B-B covalent bonds. In this study, the effect of boronizing on the corrosion resistance of AISI 1010 steel was investigated. Baybora-1 which has recently been patented was used as boronizing agent. AISI 1010 steel was borided at 950°C for 2, 4, and 6 h using the solid method. The microstructure, hardness, and corrosion rate of the samples were investigated. The change in the corrosion rate of the samples was determined by the corrosion test specified in the ASTM G31-72 standard.The results showed that the hardness of the iron boride layer formed on the surface as a result of the boronizing process was greater than that of the matrix. As a result of the boriding process, the hardness of the iron boride layer on the steel surface reached approximately eight times the hardness of the substrate matrix. The thickness of the iron boride layer on the steel sample surface was measured at 950°C for 2 and 6 h, respectively, as 45 ± 12 and 155 ± 13 µm. It was concluded that the boriding process increased the corrosion resistance of steel.