Nanoparticles of Zn and ZnO as extreme pressure (EP) additives for lubricants

Abstract

The tribological behavior of moving components and tooling in the automotive industry is a critical issue for improving tool life and increasing efficiency. This work discusses the effects of Zn and ZnO nanoparticle additives homogeneously dispersed within a metal-forming synthetic fluid at various filler fractions: 0.01, 0.05 and 0.10wt.%. Nanolubricants were evaluated under scuffing conditions at extreme pressures (EP) conditions using a four-ball tribotester in order to obtain the load-carrying capacity (poz) behavior, and overall tribological characteristics. This method has shown, with great precision, the influence of the nanofillers on the EP behavior of conventional lubricants. Worn surfaces were characterized through Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) to determine the tribological mechanisms of nanoparticles. An Alicona 3D surface measuring system was used for measuring the surface roughness of the wear scars. Both nanoparticles exhibited better friction-reducing and anti-wear properties compared to the base synthetic fluid. For Zn-based nanolubricants, an enhancement of ~180% in poz was obtained with 0.10wt.%, showing the effect of the spherical nanostructures that were tribosintered onto the surface due to the EPs of the test. Furthermore, the highest enhancement in poz (up to 250%) was achieved with incorporation of 0.10wt.% of ZnO demonstrating the potential of nanolubricants for improving the efficiency of mechanical components.

A Review of Friction Performance of Lubricants with Nano Additives

“…Zinc oxide nanoparticles have been used as a potential source to reduce the friction of lubricants in recent years [ 47 ]. Not much research has been conducted to test the suitability of ZnO nanoparticles with different lubricants.…”

Tribological and Physicochemical Behavior of a Novel Palm Grease Blended with Zinc Oxide and Reduced Graphene Oxide Nano-Additives

“…Nanomaterials [32], such as activated carbon nanoparticles [33], boron nitride [34], carbon nanotubes [35,36], graphene and its oxide [37][38][39], are considered as more eco-friendly anti-wear (AW) and extreme pressure (EP) additives to lubricants. Effective AW agents represented in metal oxide nano-additives, such as titanium dioxide [40,41] and ZnO [42][43][44], act as antioxidants in order to stabilize the physical properties of oil under harsh conditions. Bhaumik et al [42] conducted a detailed study about the effect of adding different weight percentages of ZnO to castor oil on its tribological behavior.…”