Effect of Size of Multiwalled Carbon Nanotubes Dispersed in Gear Oils for Improvement of Tribological Properties (original) (raw)
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Tribological properties of dispersed carbon nanotubes in lubricant
This study examined the tribological properties of two lubricating oils, mobil gear 627 and paraffinic mineral oils, with multiwall carbon nanotubes (MWCNTs) nanoparticles used as additives with various concentrations (0.1, 0.5, 1, and 2 wt. %). The friction and wear experiments were performed using a four ball tribotester. The samples were tested for their antiwear, load carrying capacity and friction coefficients according to ASTM D-2783, ASTM D-2596 and ASTM D-5183 standards. The experimental results show that the addition of MWCNTs to base oils exhibit good friction-reduction and anti-wear properties. The wear test results show a decreased wear by 68 % and 39 % in the case of MWCNTs based mineral oil as compared with base mobil gear 627 and paraffinic mineral oils, respectively. Furthermore, the friction reduction results show a decrease of friction about 57 % and 49 % in the case of MWCNTs based mineral oil as compared with base mobil gear 627 and paraffinic mineral oils, respectively. The weld load of the base oil containing 1 % MWCNTs was found to be 400 kgf and 125 kgf as compared with base mobil gear 627 and paraffinic mineral oils, respectively Downloaded by [University of Nebraska, Lincoln] at 19:57 28 May 2016 ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 2 which got welded at 200 kgf and 100 kgf. The morphologies and typical element distribution of the worn surfaces were characterized by SEM and EDX. The SEM micrographs and EDX chemical analysis confirm the formation of atribolayer composed of the elements from the nanoparticles.
Advances in Tribology, 2014
The paper investigates the exceptional antiwear and extreme pressure properties of multiwalled carbon nanotube based mineral oil. Different samples of oil containing varying proportions of MWNT (MWNT) and graphite were prepared. The samples were tested for their antiwear and load bearing capacity according to ASTM G99 and ASTM D-2783 standards. After pass load test in four ball tester the rubbed surfaces were investigated with Scanning Electron Microscope (SEM) images. The wear test results show a decrease wear by 70–75% in case of multiwalled nanotube based mineral oil as compared with pure mineral oil. Furthermore, it has been observed that the load bearing capacity in case of multiwalled carbon nanotube based mineral oil increases by 20% as compared to pure mineral oil. A comparison in the antiwear and load bearing capacity properties of graphite and nanotube based mineral oil was studied which showed the inefficiency of graphite based lubricant over MWNT based oil. Thus, the fin...
International Journal of Surface Science and Engineering
In the present study, the tribological performance of water-based emulsion (lubricant) was investigated by blending carbon fillers such as graphene nanoplatelets and multiwall carbon nanotubes using pin-on-disc tribometer. It was noticed that addition of GnP and MWCNT in water-based emulsion (conventional lubricant) increases the thermal conductivity and viscosity as compared to conventional lubricants. The nanolubricants were supplied with minimum quantity lubrication (MQL) technique at a constant flow rate and pressure in the sliding zone. The addition of 0.8 wt.% concentration of GnP showed 58.39% reduction in coefficient of friction and 61.80% reduction in wear depth compared to the conventional lubricant. Similarly, for 0.8 wt.% concentration of MWCNT showed 26.27% reduction in coefficient of friction and 47.35% reduction in wear depth compared to the conventional lubricant. The sliding surface micrographs were also investigated to explain the synergistic effect of nanoparticles.
Journal of Materials Research and Technology, 2016
Since their discovery in 1991 carbon nanotubes (CNTs) have attracted much interest due to their remarkable mechanical, thermal, electrical, chemical and optical properties. In connection with their mechanical properties, CNTs have been studied in various forms for tribological applications including their use as lubricant additives for oil and water. In this work, the tribological properties of functionalized nanotubes (single and multi-walled) modified with carboxylic acid when used as lubricant additives at different concentrations (0.01, 0.05%) were studied under rolling-sliding conditions in a twin-disk testing machine. The tests were performed using 5% of creepage and pressures of 0.8 GPa and 1.1 GPa. The results indicated that the presence of carbon nanotubes leads to a decrease in both friction coefficient and wear rate for both systems studied (oil and water).
Preparation and evaluation of lubricating greases based on carbon nanotube.pdf
The paper aims to preparing nano grease based on Multiwall carbon nanotube (MWCNTs) as additives. In this respect, the rheological and tribological properties of prepared nano greases with different of carbon nanotube content were studied. The microstructure of prepared carbon nanotube and nanao-greases were examined by high resolution transmission electron microscope (HR-TEM). The rheological properties of these greases with and without carbon nanotube-particles were explored at different temperatures using a brokfield rheometer. The experimental results reveal that improvement in the thermal and mechanical stabilities in addition to improvement in the oil separation. Also, the apparent viscosity increases with the increase of carbon nanotube concentration. The rheological characteristics of the obtained greases fitted with Herschel-Bulkley mathematical model. Tribological properties of the prepared greases with and without carbon nano-tube were evaluated using Pin-on-Disc tribometer. It was concluded that the prepared nano-greases have been proved to have quite favorable lubricating performance by the tribology experiments compared with blank grease.
The Multi-Walled Carbon Nano-Tubes (MWCNT) are gaining wide acceptability as an anti-wear lubricant additive because of their extraordinary tribological properties. However, full antiwear potential of the MWCNT can be derived when it is used in a proper quantity with a suitable surfactant. The aim of the present research is to identify the factors that affect the tribological performance and to employ the Design of Experiments (DOE) to study the effect of four factors: MWCNT quantity, surfactant quantity, load and speed on the tribological performance of the nano lubricant. The tribological performance of the nano lubricant is measured in terms of wear of the block sliding against the disk in a block and disk test setup. Four levels of these factors are considered for use in the design of experiments. The interaction amongst these factors is also determined. The experimental results has been analyzed and reported.
The working conditions in many industrial applications cause the tribo pair to operate in the mixed lubrication regime. Since the lubricant film thickness under these conditions is insufficient to separate the sliding tribo pair, therefore usage of lubricant with anti-wear additives is essential. The carbon nano-tubes (CNT) have recently emerged as lubricant additive having extraordinary tribological properties. In the present work, experiments have been conducted on block and disk test setup to determine the effect of using CNT as anti-wear additive in a commercial lubricant. Varying quantities of the CNT have been tried in the lubricant to conduct the wear tests. The wear of the block is quantified in terms of its weight loss after the test. The results of the wear tests are reported.
2016
Dissimilar materials with various nano forms were used as additives for improving properties of lubricants in the recent times. The potential of using functionalized (COOH) Multi-Walled Carbon Nano-tubes (MWCNTs) as additives in mineral oil grade SAE 20W40 was investigated in this study. High specific surface area of MWCNT might cause agglomeration and hence TRITON X-100 as surfactant was added to maintain MWCNT in the de-agglomeration state. However, the addition of Triton X-100 as surfactant in the mineral oil resulted in the variations of its tribological characteristics. The efficiency of MWCNT as anti-wear additive is also dependent on the properties of base oil. The weight percentage of MWCNT considered for preparing the nano-lubricant was taken to be 0.01%, 0.05%, 0.1%, and 0.2% of the lubricant weight. The surfactant Triton X-100 quantity using sonicator is taken to be 350 times the quantity of MWCNT by weight .The surface morphology of the samples was observed using Field E...