Tribological property and oxidation stability evaluation of rice bran oil with silicon dioxide nanoparticles and spicy aroma-based herbal oils as additives

Around the globe, the majority of industries are utilizing mineral oil-based lubricants because of their cost, availability, and compatibility with different engineering materials. The progressive depletion and negative impacts of mineral oil-based products on the environment have led to the search for some potential alternatives. Biodegradable and nontoxic vegetable oils are considered a potential replacement for mineral oils. However, they exhibit certain limitations such as less oxidation stability, poor cloud, and pour point characteristics. In the present study, herbal oils are used as novel antioxidants, and also the synergetic effect of nanoparticles and herbal oils are studied. The modified rice bran oil (MRBO) was formulated using rice bran oil (RBO) as base oil with optimum concentrations of additives such as ginger oil (GO), black pepper (BP) oil, and silicon dioxide nanoparticles. The wear scar diameter (WSD) was reduced significantly by 18.8% after the addition of 0.05 wt.% of SiO2 to RBO. The synergetic effect of herbal oils and SiO2 has significantly reduced the coefficient of friction (COF) of RBO by 15.5%. The oxidation stability of developed oil was also found to be better than RBO when compared to that of commercial lubricant (COM).