Phosphating Modification with Metal Ions of Carbon Steel Surface to Improve the Influence of Anticorrosion Properties

The purpose of this research is to investigate the influence of the phosphatizing process with Ni2+, Ce3+, and Ti2+ ions on the properties of the coating to obtain better corrosion protection of the metal. Steel corrosion occurs through physicochemical interaction between the metal and its surrounding environment. This leads to a change in the metal’s physical, mechanical, and optical properties that can cause damage to the functionality of the metal, which in turn may result in accidents or other malfunctions. Carbon steel grade has limited resistance to corrosion, depending on the carbon content and alloying element, the microstructure, and the surrounding environment of the material. This paper present tests that have been carried out on some of the physicochemical properties of protective epoxy and polyurethane coating on carbon steel grade. Coatings represent one of the methods available to protect metal surfaces from corrosion. Coating properties such as thickness, hardness, and adhesion were investigated. The same properties were tested by exposing the sample plates to corrosive conditions of the humid chamber and seawater. Their anticorrosion properties were explored by electrochemical impedance spectroscopy (EIS) techniques under immersion in 3.5 wt.% NaCl solutions as a corrosive medium. Part of the samples prior to application of the coatingwere modified with a phosphate solution containing metal ions: Ni2+, Ce3+, and Ti2+ to further investigate the effects of phosphatization on the properties of the coating. After exposure of the plates to the salt and moist chamber conditions, no traces of corrosion products, cracking or peeling of the coating were found on the surfaces. The adhesion properties were tested by the pull-off adhesion test. It was found that metal/polymer adhesion was satisfied according to EN ISO 4624:2016 and had the same value for all samples. However, a detailed EIS analysis showed a higher resistance of phosphate samples with Ce3+ ions than samples that were phosphated with Ni2+ and Ti2+ ions and those that did not have a sparingly soluble phosphate salt layer.

Anticorrosion Efficiency of Inhibitor Coatings Based on Ammonium Cation with Different Substituents: The Influence of Wettability and Molecular Structure

In this work, different cationic surfactants with various aliphatic and aromatic ammonium cations were used to prepare inhibitor coatings and were characterized by different techniques such as IR spectroscopy and NMR. The inhibitor coatings were prepared by electrografting on the steel surface and their anticorrosion properties were evaluated in different media (HCl, H2SO4 and NaCl solutions). The electrochemical potentiodynamic polarization technique was used to study the inhibition efficiency of the prepared coatings. The dependence of the wetting properties of the electrografted layer and its homogeneity on the molecular structure of the prepared surfactants was studied. Particular attention was paid to the relationship between the properties of these surfactants in terms of critical micellar concentration, packing and wetting, and the anti-corrosion efficiency of their coatings. In this paper, we discuss the synergistic inhibition effect and the anticorrosion efficiency.

Development of Metal Cladding Additives for Agricultural Machinery Friction Unit Parts

The choice of materials for the formulation of the metal cladding additive has been theoretically substantiated. A process has been developed and a copper-containing lubricant composition has been synthesized. It is shown that the use of a metal cladding additive having antifriction and antiwear properties reduces 2.9 times the part wear rate. The effect of the additive on the anticorrosion properties and thermal-oxidative stability of the base oil has been studied.

Evaluation of corrosion in steel reinforced concrete with brick waste

The massive demolition of old buildings in recent years has generated tons of waste, especially brick waste. Thus, a concern of recent research is the use of this waste for the production of environmentally friendly concrete. At the same time, corrosion of the reinforcement steel rebar in classical concrete is a current problem. In this context, in the present paper a study was carried out on the corrosion of metal reinforcement in cement mortars with added brick waste. The corrosion process was analyzed on four compositions of mortars without and with 15%, 25% and 35% brick waste replacing the sand. The brick waste has majority content in SiO2, Al2O3, FeO3 and CaO. The grain size distribution of brick waste was close to that of the sand (dmax = 2 mm). The preparation method of the samples was similar to ordinary mortars. The corrosion action on the rebar in concrete, at different brick waste concentrations, was investigated by electrochemical measurements (polarization curves and electrochemical impedance spectroscopy (EIS)) at 1 month and 26 months. The results obtained at 26 months revealed that the addition of the brick waste in mortar improved the anticorrosion properties in the case of all samples compared with the etalon mortar. The best results were obtained in the case of the sample with 15% brick waste (the efficiency was ≈ 90%). The corrosion intermediary layer formed on the rebar surface was evidenced by SEM-EDX.