Copper oxide nano-particles as friction-reduction and anti-wear additives in lubricating oil

Abstract

Lubricants based on hydrocarbon-type mixtures do not satisfy all requirements of OEMs (Original equipment manufacturers) for modern applications. The usual solution is the addition of small amounts of certain additive compounds that render significant improvements in base oil properties such as oxidative degradation, tribological performance and other characteristics. This study examined the tribological behavior of copper oxide nanoparticles as additives in mineral based multi-grade engine oil. All tests were performed under varying loads and concentrations of nanoparticles in lubricating oil. The friction and wear experiments were performed using pin on disc tribotester. The results demonstrated that nanoparticle additives can effectively improve the engine oil lubricating properties. This is because nanoparticles enter the friction zone along with the flow of lubricant. They convert sliding friction into rolling friction, thus reducing the effective friction coefficient. This work also included an analysis of worn surface morphology by scanning electron microscopy. This surface examination revealed that nanoparticle additives resulted in smoother worn surfaces. From the viscosity test it can be inferred that viscosity of engine oil contains CuO nanoparticles is a function of nanoparticles concentration. Stribeck curves are used to reveal the lubrication regimes where the CuO nano-particles are most effective. It was found that the addition of CuO nanoparticles to the base oil results in up to 50% reduction in coefficient of friction in the mixed lubricant regime.

Tribological investigation of diamond nanoparticles for steel/steel contacts in boundary lubrication regime

“…It can be observed that the coefficient of friction increases with increase in load. For a lubricant containing CuO, previous studies reveal that only a thin layer of lubricant can be maintained in the boundary lubrication regime and the direct contact between asperities plays a dominant role (Jatti and Singh 2015). The increase in the coefficient of friction with increase in load is therefore due to the increased interaction between the asperities of two sliding surfaces.…”

Metal-containing nanomaterials as lubricant additives: State-of-the-art and future development

“…Cu NPs and Ag NPs were used as metal cladding modifiers of nanolamellar MoS 2 [144,145] and WS 2 [137] particles. It was demonstrated that such nanocomposite lubricants changed the COF of the original [128] lubricant and significantly improved its wear resistance. In Ref.…”

Environmental behavior, potential phytotoxicity, and accumulation of copper oxide nanoparticles and arsenic in rice plants

“…Copper‐based engineered nanomaterials (ENMs) are unique among the most widely used ENMs because Cu contains 3 oxidation states (Cu 0 , Cu 1+ , and Cu 2+ ) and exhibits many unique and useful physicochemical properties . In particular, CuO NPs are being widely used in many applications including high‐efficiency catalysts , energy‐saving materials , high‐temperature superconductors , gas sensors , antimicrobial agents , environmental remediation , and friction‐reduction and anti‐wear additives .…”