In this paper, we have developed conditions for the deposition of zirconium oxide coatings from solutions containing hexafluorozirconic acid as well as tungsten and molybdenum salts on a steel base. Based on electrochemical studies, it was shown that the addition of tungsten and molybdenum salts to the solution to deposit zirconium oxide coatings led to the inhibition of the anodic process of iron ionization. It was shown that the optimal conditions for the deposition of oxide-zirconium coatings on the surface of steel samples from a solution of 0.2 g/L Zr (IV) + 0.15 g/L W (VI) + 0.1 g/L Mo (VI) were a deposition temperature of 30 °C and time of 10 min. The thickness of the oxide-zirconium coatings formed under these conditions was 64.72 nm, the adhesion value was 3.17 MPa/s, and the corrosion resistance was 26 s according to Akimov’s drop method. The depth of corrosive penetration, determined in the salt fog chamber, did not exceed 2 mm after 240 h of testing, meeting the requirements for adhesive layers under the paintwork.

In this paper, we developed a process for the deposition of adhesive oxide-zirconium coatings from solutions of hexafluorozirconic acid in the presence of Co (II) and Ni (II) ions on a steel base. The optimal conditions for the formation of oxide-zirconium coatings (concentrations of hexafluorozirconic acid, Co (II) and Ni (II) ions, temperature, pH, deposition time, thickness) are determined. The corrosion resistance of the obtained coatings was investigated depending on the change in the process parameters. It is found that the stabilization of the current-free potential and the optimum thickness of the zirconium oxide coating are achieved at close time parameters. The results of corrosion tests are in agreement with the adhesion strength of the obtained oxide-zirconium coatings on iron base in the temperature range 30-40 o С.It is shown that the formed oxide-zirconium coatings satisfy the requirements imposed on adhesion layers for paint coatings.

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In order to obtain sulfur-containing organophosphorus compounds that are promising as extractants of heavy metals, the interaction of elemental phosphorus and sulfur with alkyl bromides catalyzed using strong bases was studied. According to the task, the reaction of non-toxic and non-flammable red phosphorus with alkyl bromides under conditions of phase transfer catalysts (PTC), followed by the introduction of elemental sulfur into the reaction medium, were studied. It is shown that alkyl bromides interact with red phosphorus when heated (95–105 °C, 5–8 h) under conditions of phase transfer catalysts (PTC) in a two-phase system: a 60% aqueous solution of KOH-toluene-benzyltriethylammonium chloride (BTEAC) forming a mixture of organophosphorus compounds along with alkylphosphines (57–60%), are the main reaction products; alkylphosphine oxides are also formed (40–43%). The introduction of elemental sulfur (solution in toluene) at the final stage of the process into the reaction mass cooled to 40–60 °C leads to the expected alkylphosphine sulfides, which are the result of the interaction of alkylphosphines with sulfur. The formation of complex mixtures of products prevents the release of target alkylphosphine sulfides in individual form. However, the synthesized mixture of alkylphosphine sulfides and alkylphosphine oxides without separation into individual components is promising for studying its extraction properties in relation to heavy metals. Testing of the extraction properties of synthesized mixtures of alkylphosphine sulfides and alkylphosphine oxides in relation to heavy metals (Ni, Co, Zn, Pb) and noble metals (Ag) showed that the resulting mixtures of tertiary phosphine oxides and phosphine sulfides are highly effective extractants. The degree of extraction in relation to Ni, Co, Zn, and Pb varies from 99.90 to 99.99%, and for Ag from 99.56 to 99.59%.

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