Study of the inhibitory ability of inorganic di- and polyphosphate compositions

Abstract

The article considers the anticorrosive properties of inorganic di-and polyphosphate compositions in relation to St-3 steel, depending on the pH of the medium, the nature and concentration of phosphate, and the nature of the modifier ion. The research was conducted using GOST-based methods: gravimetry, potentiometry, photocolorimetry, infrared spectroscopy and scanning electron microscopy. On the basis of experimental data, quantitative indicators of corrosion process were determined: the rate of corrosion process, the degree of protection, the depth index, the coefficient of inhibition and the assessment of the stability of the formed film on the ball scale of corrosion resistance against steel. The analysis of experimental data allows to establish the influence of the above factors on the corrosion processes in the systems under study. The experimental data are supplemented by thermodynamic calculations of the corrosion process parameters, the results of which correlate well with the kinetic data of the process under study. In the course of the research work, the analysis of corrosion deposits was also carried out. The regularities established during the work contribute to the creation of effective di-and polyphosphate inhibitors with the highest degrees of protection.