Assessment of boundary lubrication in biodiesels by nanotribological tests
authors Maru, MM; Almeida, CM; Silva, RF; Achete, CA
nationality International
journal ENERGY
author keywords Nanotribology; Boundary lubrication; Biodiesel; Friction
keywords DIESEL FUEL LUBRICITY; FORCE MICROSCOPE; FRICTION; CONTACT; ESTERS; TEMPERATURE; DEPENDENCE; TRIBOLOGY; BEHAVIOR; AFM
abstract Nanoscale measurements using atomic force microscopy are performed in order to scrutinize the friction phenomena observed in microscale ball-on-disc tribological tests under (boundary lubrication) BL regime. Two reference biodiesels, one derived from a vegetable source (soybean) and the other from animal fat, are compared. A linear dependence of the friction coefficient (mu) with the Stribeck parameter (S = viscosity x velocity/load) is observed: mu = 0.11 - 26.54 x S for the animal fat and mu = 0.12 - 51.56 x S for the soybean biodiesel. The nanotribological tests allowed highlighting the cohesion component of friction force in the BL regime that is associated to the intrinsic characteristics of the biodiesels, the respective friction coefficients being mu = 0.0206 for the animal fat and mu = 0.0233 for the soybean biodiesel. The better lubricity of the animal fat biodiesel compared to the soybean observed in microscale is attributed to the presence of sulfur and to the higher amount of mono- and di-glycerides contaminants in it. The polarity and/or chemical affinity of the respective sulfur and OH groups facilitate them to reacting with the steel surfaces during the rubbing action. At nanoscale level, the same ranking in friction is observed among the biodiesels, being that here the friction phenomena are attributed to the cohesive forces other than those related to viscosity. (C) 2013 Elsevier Ltd. All rights reserved.
publisher PERGAMON-ELSEVIER SCIENCE LTD
issn 0360-5442
year published 2013
volume 55
beginning page 273
ending page 277
digital object identifier (doi) 10.1016/j.energy.2013.03.036
web of science category Thermodynamics; Energy & Fuels
subject category Thermodynamics; Energy & Fuels
unique article identifier WOS:000321228400028
  ciceco authors
  impact metrics
journal analysis (jcr 2019):
journal impact factor 6.082
5 year journal impact factor 6.046
category normalized journal impact factor percentile 89.245
dimensions (citation analysis):
altmetrics (social interaction):



 


Sponsors

1suponsers_list_ciceco.jpg