Electrochemical investigation of protection effect of mineral-polymer coatings on steel for Housing and Communal Services

Abstract

The durability and protection effect of mineral-polymer coatings (MPC) on steel developed by SU-57 сompany for heat supply and housing and communal services facilities are determined. The thickness of the coatings is 150…700 μm. It is shown that MPC with a thickness of 150…500 μm in network water at 95 °C are resistant, when kept for 1…8 days, an increase in their mass is observed due to the overgrowth of MPC pores with hardness salts, corrosion products and hydroxides, which is confirmed by micrographs of the MPС surface. The outer layer of the MPC with a thickness of 700 μm is more porous and undergoes the dissolution under these conditions at an insignificant rate. According to the results of determination of the corrosion rate of steel with MPC (by the method of linear polarization resistance) in 3% NaCl at 20° and 95 °C, as well as in network water at 95 °C, coatings with a thickness of 500 and 700 μm have the highest protective ability, 82…89%, the porosity of the coatings is 11…18%. MPP on steel has a high adhesion. The optimal thickness of the MPP for the protection of heat supply and housing facilities according to 11…18%. MPC on steel has a high adhesion. The optimal thickness of the MPC for the protection of heat supply and housing facilities according to the results of the work is 500 μm