The investigation of different particle size magnesium-doped zinc oxide (Zn0.92Mg0.08O) nanoparticles on the lubrication behavior of paraffin oil

Kalyani Kalyani,D Kumar,R B Rastogi,V Jaiswal

doi:10.1007/s13204-015-0471-1

Kalyani Kalyani, D Kumar + Show 2 more

Open Access

https://doi.org/10.1007/s13204-015-0471-1

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Abstract

Magnesium-doped zinc oxide (Zn0.92Mg0.08O) (ZMO) nanoparticles of 23 nm particle size have been synthesized by auto-combustion method. The variation in particle size of these nanoparticles has been performed by their further calcination at 800 and 1000 °C for 2 h and the corresponding calcined particles are designated as ZMO-1 and ZMO-2, respectively. The nanoparticles have been characterized by powder-XRD, scanning electron microscopy (SEM), energy dispersive X-ray and transmission electron microscope. The effect of particle size on the antiwear lubrication behavior of paraffin base oil has been investigated on four-ball lubricant tester. The tribological tests of these nanoparticles as antiwear additives have been studied at an optimized concentration (0.5 %w/v) by varying load for 30 min test duration and by varying the test durations at 392 N load. Various tribological parameters such as mean wear scar diameter, friction coefficient (µ), mean wear volume, running-in and steady-state wear rates show that these nanoparticles act as efficient antiwear additives and possess high load-carrying ability. From these tribological tests it has been observed that the lubrication behavior of studied nanoparticles is strongly size-dependent. The best tribological behavior is shown by nanoparticles of the smallest size, ZMO. Being sulfur, halogen and phosphorous free, ZMO nanoparticles have potential to be used as low SAPS lubricant additives. The SEM and atomic force microscopy analysis of the worn surfaces lubricated with ZMO nanoparticles at 392 N applied load for 60 min test duration show drastic decrease in surface roughness. The values of surface roughness of different additives are in good agreement with their observed tribological behavior.

Highlights

Lubricants play an important role in reducing friction and wear and increasing the life of contact interfaces
The lubrication properties of these different sized ZMO nanoparticles in paraffin oil have been evaluated on fourball tester machine
In absence of additives in the base oil, the mean wear scar diameter (MWD) was found to be very large, but in presence of ZMO nanoparticles it was fairly reduced at each concentration

Summary

Introduction

Lubricants play an important role in reducing friction and wear and increasing the life of contact interfaces. A lot of organic compounds have been used as antiwear and extreme pressure lubrication additives These additive molecules basically contain active elements such as phosphorous, sulfur, halogens, nitrogen and oxygen as well as polar groups for strong adsorption (He et al 2002). Additives with these active elements get adsorbed on the contacting metal surface and form a tribochemical film under lubricating conditions. Modern engine oils contain a large number of additives, but the most influential compounds on the tribological performance of the lubricants are antiwear zinc dialkyldithiophosphates (ZDDPs).

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