Study of polymethylsiloxane as an inhibitory additive to mineral oil

• S.M. Reshetnikov^1,2, I.N. Shabanova¹, Е.А. Naimushina^1,3, N.S. Terebova¹ and S.K. Gaidukova²

¹ Udmurt Federal Research Center, Ural Branch, Russian Academy of Sciences, 426067 Izhevsk, Russian Federation
² Udmurt State University, Universitetskaya Ulitsa, 1/1, 426034 Izhevsk, Udmurt Republic, Russian Federation
³ Izhevsk State Technical University, 426069 Izhevsk, Russian Federation

Abstract: The conceptual feasibility of creating mineral oil formulations using commercially produced polymethylsiloxane (PMS) as an inhibitory additive has been demonstrated. A gel containing 70 wt.% PMS and 30 wt.% water (trade name polymethylsiloxane polyhydrate) was studied as the PMS sample. This gel, when mixed with mineral oil (mineral oil of IS-20 grade according to GOST 20799-2022 was used), formed a homogeneous mixture that partially separated on storage. The PMS content in the oil was varied from 1 to 10 wt.%. The protective effect of the resulting formulations applied to samples of steel 10 (GOST 1050-2013) was studied using a Monicor corrosion meter in a corrosive environment simulating moisture condensation in industrial cities. The protective effect of the resulting mineral oil formulations has been shown to appear only after heating the samples with an applied layer of inhibited oil to a temperature of 50–150°C. A study by means of X-ray photoelectron spectroscopy has shown that the formation of chemisorption bonds between iron and silicon and oxygen atoms within PMS is enhanced during such heating (thermochemical activation). Depending on the PMS concentration in the oil and the heating temperature, the resulting adsorption layer decreases the corrosion rate by a factor of 5 to 15. The addition of PMS as an inhibitor into a model mineral oil medium would make it possible to use the compositions obtained for creating thin surface layers of protective mineral oil formulations, which would not require re-preservation of products after storage between the operation periods.

Keywords: polymethylsiloxane, inhibitors, protective anticorrosion layer, corrosion meter, X-ray photoelectron spectroscopy

Int. J. Corros. Scale Inhib., 2023, 12, no. 4, 2431-2440
doi: 10.17675/2305-6894-2023-12-4-52

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