Influence of dipinaconborates on the corrosion resistance of ST3 steel in synthetic detergent solutions

Experimental data on the effect of lithium dipynaconborates (DPKBL), sodium (DPKBN) and potassium (DPKB) on the corrosion resistance of St3 steel in 3 % aqueous solutions of Labomid-203, MS-8 and Temp-100A synthetic detergents have been obtained. By measuring the stationary potentials of steel in solutions of synthetic detergents, the optimal concentration of dipinaconborates was revealed, which is 20 g/l, at which the highest corrosion resistance of steel is achieved. Studies of the corrosion-electrochemical behavior of St3 steel in 3 % aqueous solutions of Labomid-203, MS-8 and Temp-100A detergents showed that in the presence of dipinaconborates, the anode current density, at the same potentials, is much lower, and the passivation region is larger. than in CMC solutions. It was found that the corrosioninhibiting ability of dipinaconborates in CMC solutions increases in the series DPKBL < DPKBN < DPKBK, and potassium dipinaconborate has the greatest anticorrosive property. Dipinaconborates reduce the corrosion rate of steel at a washing solution temperature of 80 °C, the degree of protection is in the range from 71.4 to 90.6 %. And the braking coefficient is from 3.6 to 10.4. By analyzing the obtained experimental data, it was concluded that dipinaconborates increase the corrosion resistance of St3 steel and can be recommended as an anticorrosive additive to synthetic detergents.

Effect of leucine on the activation energy of the corrosion process of St3 steel in 0,04% CH3COOH solution – kerosene system

In this investigation we studied the temperature dependence of the protection effect of St3 steel against corrosion in 0,04% CH3COOH solution-kerosene system by gravimetric method of leucine (derivative of aliphatic monoamino monocarboxylic acids – AL-MAMCA: with the general formula CH3-CH(CH3)-CH2-CH(NH2)-COOH). Previously at 20 ºC we investigated this corrosion process in various two-phase acid and neutral electrolyte solutions in hydrocarbon systems and revealed a good protection effect of leucine. On the basis of the obtained data, the activation energy in the corrosion process of St3 steel has been calculated without and in the presence of the leucine in the aggressive system shown by analytical and graphical methods (graph of dependence of lgK on 1/T). It was found that the addition of leucine to the aggressive system in terms of corrosion causes a significant increase in the activation energy of St3 steel in the corrosion process, and thus complicates the process of this undesirable process. It has been shown that in parallel with the increase in the temperature of the aggressive environment in terms of corrosion, the previously physically adsorbed leucine molecules on the surface of St3 steel are gradually replaced by chemically adsorbed ones, thus further strengthening the metal – inhibitor bond.

OBTAINING BLACK METAL CORROSION INHIBITORS METHOD OF PHYSICAL AND CHEMICAL ANALYSIS

Целью данной работы явилось получение нового эффективного, экологически безвредного ингибитора коррозии из недорогого и недефицитного сырья. Исследована система моноборат натрияформамид-вода при 25 °C, для чего воспользовались методом физико-химического анализа. Получено новое двойное соединение (моноборатнатрийформамид – МБНФ) состава 2NaBO2 – HСONH2 – 2H2 O. Полученные в ходе экспериментов сведения подтверждают получение нового амидоборатного комплекса и позволяют предположить, что он обладает существенными ингибиторными свойствами. Для подтверждения или отклонения гипотезы, что полученное боратное соединение обладает ингибиторными свойствами, гравиметрическим методом было изучено влияние его концентрации на скорость коррозии, ингибиторный эффект и степень защиты стали Ст3 в 3 %-м растворе NaCl. Для опытов использовали образцы размерами 100х25х2 мм из стали Ст3. Установлено, что лучшие ингибиторные свойства МБНФ проявляются при его концентрации 5 г/л в коррозионнойсреде, так как все три показателя, которыми характеризуются ингибиторы коррозии, достигают экстремума при концентрации МБНФ 5 г/л в 3 %-м растворе NaCl: скорость коррозии снижается с 30,32 до 15,36 г/м2 ·ч·10–3, ингибиторный эффект и степень защиты повышаются до 1,93 и 92,1 % соответственно. На основании результатов экспериментов полученное соединение МБНФ можно рекомендовать в качестве эффективного ингибитора в составе противокоррозионных композиций для защиты оборудования животноводческих комплексов и сельскохозяйственных машин в период межсезонного хранения, а также в растворах синтетических моющих средств для мойки деталей при ремонте агрегатов машин с целью повышения их противокоррозионных свойств. he aim of the research was to obtain a new effective, environmentally friendly corrosion inhibitor from inexpensive and non-defi cient raw materials. By the method of physical and chemical analysis, the sodium monoborate - formamide - water system was studied at 25°C. For the experiments, sodium monoborate and formative chemically pure grade were used as starting materials. The formation of a new double compound (monoboratesodiumformamide – MBSF) with the composition 2NaBO2 – HСONH2 – 2H2 O was established. Using IR spectroscopy, data have been obtained that allow us to interpret new amidoborate complexes and predict their effective inhibitory properties. To confi rm or reject the hypothesis that the obtained borate compound has inhibitory properties, the infl uence of its concentration on the corrosion rate, inhibitory effect and degree of protection of St3 steel in a 3% NaCl solution was studied by gravimetric method. For the experiments, we used samples with sizes 100х25х2 mm made of St3 steel. It was found that the best inhibitory properties of MBSF are manifested at a concentration of 5 g/l in a corrosive environment, since all three indicatorsthat characterize corrosion inhibitors reach an extremum at a concentration of MBSF of 5 g/l in a 3% NaCl solution: the corrosion rate decreases from 30.32 to 15.36 g/m²·h · 10–3, the inhibitory effect and the degree of protection increase to 1.93 and 92.1%, respectively. Based on the results obtained, the obtained MBSF compound can be recommended as an effective inhibitor in the composition of anticorrosive compositions for protecting equipment of livestock complexes and agricultural machines during off-season storage, as well as in solutions of synthetic detergents for washing parts when repairing machine assemblies in order to increase their anticorrosive properties .