Improvement of antiseizure, antiwear, and anticorrosion properties of thin nitrided layers by impregnation with oil‐ or solvent‐based formulations

Abstract

AbstractThe results of some corrosion and tribological investigations are presented in this paper. Samples with thin (white layer, WL = 16.5 μm) nitrided layers on 45‐grade steel obtained in a controlled gas nitriding process (at 570°C, 6 h; WL = 16.5 μm; grey porous zone or grey layer, GL = 6.0 μm) and impregnated by multifunctional oil‐based formulations containing BS‐MOD corrosion inhibitor (CI) as well as tribological additives (TAs) were used. The TAs when present alone (without the CI) in oil have no corrosion‐inhibiting features and also do not affect the corrosion resistance of WLs impregnated with formulations containing both the CI and TAs; corrosion resistance is mainly connected with the presence of the CI. Synergistic effects observed between TAs and the CI as well as TA concentration vs. BS‐MOD in multifunctional additives are more apparent in seizure features and wear resistance of impregnated WLs. The influence of the TAs in combination with the CI depends on their type and concentration; it can be positive or negative. Hence, the choice of composition of CI and TA for multifunctional impregnating formulations is determined, above all else, by the relation between the CI and the grade of TA. The anti‐corrosion effect as well as the tribological function is dominated by the CI component (BS‐MOD).