THE STUDY OF THE INHIBITORY ABILITY OF INORGANIC ORTHOPHOSPHATE COMPOSITIONS

Abstract

The article deals with the anti-corrosion properties of inorganic orthophosphate compositions in relation to St-3 steel depending on the pH of the medium, the nature and concentration of orthophosphate, the nature of the ion modifier. The studies were conducted according to GOST methods. Methods: gravimetry, potentiometry, photocolorimetry, X and SEM. 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. During the research also the analysis of the corrosion deposits, showing the formation of gidroksiapatit compounds on the metal surface. Corrosion resistance of the formed compounds in these systems on the basis of the calculated values of the deep corrosion index corresponds to 4 points (according to GOST 5272-90). The regularities established during the work contribute to the creation of effective orthophosphate inhibitors with the highest degrees of protection.

References

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