Characteristics of latex coatings for steel protection against corrosion

Abstract

This paper examines the kinetics of corrosion for steel St3 samples covered with a latex coating 69B–2k, manufactured by Kapitel LLC (Irkutsk), by analysing gravimetric tests performed using steel samples. A 3 wt % solution of sodium chloride was used as an electrolyte. The accuracy of the obtained results was confirmed by carrying out at least two parallel experiments. Prior to coating, the metal surface of samples was carefully prepared as per GOST R 9.907-2007. Film coatings were applied onto the metal surface by threefold dipping of samples in liquid latex followed by drying within 24 hours. The quality of the coating prior to and following the experiments was assessed visually and by microphotography. Gravimetric studies were carried out under temperature control (25 ± 0.2°C) in the working area. At the same time, changes in the sample mass were recorded over a controlled time interval (from 1 to 24 hours). The results of weighing samples obtained prior to and following the experiments were analysed using a kinetic flowchart, in which the type of reaction is defined in stages in a natural sequence. Kinetic analysis of the gravimetric results confirmed the absence of characteristic signs associated with chemical interactions on the surface of steel St3 coated with latex 69B-2k. Out of the known mathematical models of phenomenological kinetics, it is admissible to use a first-order equation to describe the course of a simple reaction during heterogeneous interaction, where the penetration of reagents through a latex film comprises a limiting stage. The kinetic analysis showed that it is necessary to study the properties of latex films; a strategy for further corrosion studies was determined.