AN EXPERIMENTAL INVESTIGATION OF THE IMPACT OF NANOPARTICLES ON THE TRIBOLOGICAL PROPERTIES OF 15W40 LUBRICATING OIL
INTRODUCTION
Effort has been made to develop advanced lubricating oil to improve the tribological properties of the tribopair and service life. The introduction of nanoparticles makes them promising contender as it possess better physical and chemical properties than the base material. The nanoparticles blended in lubricating oil emerged as new tool for improving the tribological properties and service life of the lubricant.
When the dimensions of any material got reduced to nano level, a significant change appears in the physical, chemical and mechanical properties as compared to the bulk material. The 2D structure and reduced grain size of nanoparticles enables large surface area to volume ratio, large surface energy, high hardness and high toughness [1].
The lubricant serves the prime function of reducing friction by avoiding material to material contact, it also provides an atmospheric insulation to the material [2]. The majority of the lubricants have about 90% of hydrocarbons rest is organic phosphorus and sulfide compounds used as a performance booster for the lubricant.
The nanoparticles may prove to be the correct replacement of the harmful lubricant additives as they reduce friction and wear, and provide high extreme pressure performance of the lubricant [3-6] The tribological properties
- enhancement by the use of nanoparticles in the lubricant as additives ~ 2% w/w may be due to; rolling effect provided by the nanoparticles as the tribopair interface resulting in low friction and wear, low melting point melts and get deposited in the tribopair surface resulting in the reduction of friction and wear, nanoparticles may enter the cracks on the surface of tribopair, reduces friction and wear. The blending of solid particles (nanoparticles) increases extreme pressure properties of the lubricant [7-11].
- Copper nanopowder in lubricating oil produced in-situ thin layer over the tribopair hence reduces friction at higher loads and higher sliding speeds [12-14].
- Graphite nanosheets blended with paraffin oil (1.0×10−2wt%) tested on four ball tester improved tribological and extreme pressure performance of paraffin [15].
- Nanoparticles of SiO2 blended in 15W40 lubricating oil was rheologicaly stable and improved anti-wear and anti-friction property of 15W40 lubricating oil [16,17].
- WS2 nanoparticles added to paraffin and SA 90 lubricating oil showed significant decrement in wear and friction force got reduced ~ 50% [18].
- CuO nanoparticles blended in the lubricant showed ~ 273% improvement in load carrying capacity and slight improvement in the tribological properties due to formation of tribo-sintered layer of CuO over the tribopairs [19,20]
It has been observed from the literature that the blending of nanoparticles in the lubricant showed significant decrement in wear and friction, moreover improved the service life of the lubricant. Hence the nanoparticles may be used as lubricant blenders to produce advanced lubricant. Thus the objective of this study is to produce a stable nanolubricant and investigate the influence of various nanoparticles (SiO2, WS2, Cu, CuO and graphite) on the tribological properties of 15W40 Lubricating oil.