Experimental studies on viscosity and tribological characteristics of blends of vegetable oils with CuO nanoparticles as additive

Abstract

High biodegradability, renewability and low toxicity of vegetable oils make them excellent lubricating base oils. Coconut oil (CO) when used as a lubricant at metallic interfaces exhibits a low coefficient of friction but high wear rate compared to mineral oils, which limits its application as a commercial lubricant, whereas mustard oil (MO) exhibits better wear resistance. The main objective of this work is to obtain an optimal blend of MO and CO to be used as an environment-friendly base oil and to add an optimal concentration of nanoparticles as an additive to improve the viscosity and reduce the friction and wear rate. The experiments are performed on the blends with MO/(CO + MO) ratio ranging from 10 to 50% and the addition of CuO nanoparticles with concentrations ranging from 0 to 0.4 wt.%. The viscosity and tribological analyses of the CO, MO, their blends, and mineral oil (SAE20W40) are carried out and compared. Both the coefficient of friction and wear scar diameter are found to be lower than those of mineral oils. Further improvements in the tribological characteristics of the blends are attained by the addition of CuO nanoparticles in small concentrations, 0.2 wt.% being optimal.

A review of the tribological properties of nanoparticles dispersed in bio-lubricants

“…39 Using thermo-gravimetric analysis, it was found that the OOT of the thermal degradation of CO, mustard oil (MO) and a blend of (50% MO + 50% CO) is (300, 334, 311°C), respectively, while that of mineral oil (SAE20W40) is 290°C. 99 The temperature at which the rice bran oil begins losing mass is increased from 220°C to 260°C and 275°C due to the addition of 0.25 wt% and 0.5 wt% CaO nanoparticle additives, respectively. This finding demonstrates that the thermal stability of rice bran oil increased by 18.2% and 25% with the addition of 0.25 wt% and 0.5 wt% CaO nanoparticles, respectively.…”

“…A brief comparison of sustainability and durability enhancements of bio-lubricants against oxidation and high temperature 39,99,114. …”

Experimental studies on viscosity, thermal and tribological properties of vegetable oil (kapok oil) with boric acid as an additive

“…Mineral oils are mostly used in the motor and engine applications, which are also obtained from the petroleum-based crude oil. The mineral oil is harmful to the environment which causes more toxicity and non-biodegradable [3]. The mineral oil lubricants have hydrocarbons which cause those effects and the natural lubricants are obtained from esters [4].…”

Recent advancements in nano-lubrication strategies for machining processes considering their health and environmental impacts

“…Taking this environmental concern into consideration, most research works are aimed towards biofluid and vegetable oil which are non-toxic in nature and are easily biodegradable. Vegetable oils have a better boiling point, good flash point, high viscosity index and higher lubrication properties which resulted in less consumption from misting [11][12][13]. Choi et al [14] reported that the oil-based NF exhibited better thermal conductivity and convective heat transfer coefficient but there were some problems associated with these NFs due to the formation of the hydrophobic coating layer on the powder surface.…”