Development of lubricious, non-toxic, and corrosion-resistant metalworking fluid: A possible replacement for mineral oil-based fluids

Abstract It has been decades to mitigate the human and environmental health-related issues associated with mineral oil-based metalworking fluids (MWFs). The present work proposes the use of natural and renewable ingredients (soybean oil, neem oil, gum arabic, guar gum, and water) to develop non-toxic, environmentally friendly, corrosion-resistant, and lubricious MWFs. The performance of the formulated fluids (FFs) was evaluated and benchmarked with mineral oil-based commercial MWF (CF). The novel use of guar gum and neem oil has improved the corrosion resistance comparable to that of CF, as indicated by the potentiodynamic polarization study. The tribological response confirmed that the FFs were lubricious and wear-resistant. In comparison to highly cytotoxic CF, the FFs demonstrated no cytotoxicity to human osteoblast-like cells (MG-63) in MTT assay and Live-dead cell assay. The improved tribological and corrosion responses are attributed to the chemisorption of gum acacia molecules and physisorption of guar gum molecules to the sliding surfaces. Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) confirmed the presence of carbon-rich lubricous tribofilm on the worn surface that aids the tribological process.