Study of the anticorrosion properties of a carboxylate inhibitor in a coolant formulation

The operation of internal combustion engines (ICE) using water as a liquid heat carrier leads to intense corrosion and deposit formation. Therefore, it is advisable to incorporate a corrosion inhibitor with a high protective effect into the coolant composition. The study aimed to evaluate the efficiency of a coolant containing a carboxylate corrosion inhibitor and the corrosion resistance of metal elements in an ICE cooling system. The authors developed a prototype coolant, VN-RU-30, with the following composition: 48% water, 48% ethylene glycol, and 4% carboxylate corrosion inhibitor. The prototype was compared with commercially available coolants, OZh-40 LENA and CoolStream Standard 40. According to GOST 28084-89, the physicochemical parameters of VN-RU-30, OZh-40 LENA, and CoolStream Standard 40 were determined, and their corrosive effects on samples of M1 copper, POS-40-2 solder, L-63 brass, St3 steel, SCH-20 cast iron, and AK-7 aluminum alloy were compared under static conditions. The protective effect of the VN-RU-30 prototype was found to be comparable to the reference coolants. To evaluate the protective efficiency of the VN-RU-30 coolant, the authors conducted tests on a model simulating an engine cooling system subjected to corrosion for 336 hours. It was established that VN-RU-30 neutralizes corrosion products on metal surfaces and effectively inhibits further corrosion processes (protective effect exceeding 98%). Field corrosion tests lasting 46 months demonstrated the integrity of the metal components in the ICE cooling system when using VN-RU-30, compared to water, which intensified corrosion and deposit formation. The results confirm the high protective efficiency of the VN-RU-30 coolant for ICE cooling systems; it is advisable for use in engine operation, restoration, and long-term preservation.

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