Inhibition corrosion of zinc in concentrated alkaline electrolyte by combination of organic and inorganic compounds

Background. Zinc is widely used in chemical current sources (CCS) with alkaline electrolytes. One of the promising ways of self-discharge reduction and the service life improvement of the CCS is the use of zinc corrosion inhibitors. However, nowadays there is only a small number of known compounds that inhibit the corrosion of zinc alkaline, and the mechanism of the protective action of poorly understood.Objective. The objective is to study the influence of nitrohen-, oksyhen- and sulfur-containing organic compounds and their combinations with inorganic matter on corrosion of zinc in concentrated alkaline electrolyte, identifying the mechanism of their protective effect.Methods. The research was carried out by mass-metrical, volum-metrical and electrochemical methods with sheet (brand U0) and powder zinc10 M in KOH and in the same solution with inhibiting additives. Adsorption studies were performed by method of electro-capillary curve removal on a mercury electrode. Mixture state of organic and inorganic compounds was studied by NMR spectroscopy. Zinc surface state was studied by Auger spectroscopy coupled with ion etching after corrosion tests.Results. Combinations of polyoxyethylenealkyl ethers (FC VIS-15, DS-10, OP-4) and benzotriazole with salts of calcium and magnesium show high protective properties during zinc corrosion in10 M KOH. Protection degree of zinc electrode if any exists reaches 75 %. Inhibitors inhibit the process of hydrogen evolution in alkaline electrolytes but they do not affect significantly on anodic dissolution of zinc.Conclusions. There is the improvement of protective effect of organic inhibitors if there is calcium and magnesium in alkaline solutions. The obtained results indicate the prospects of using studied corrosion inhibitors in chemical power sources with zinc anode and alkaline electrolyte.