The tribological performance of the sliding bearings which are probably made of polymers, which is subjected to magnetic field, is of great intense. The wear of epoxy composites filled by metallic particles such as iron, copper and aluminum scratched by steel indenter is investigated. The wear scar width of the scratch was measured by an optical microscope. It was found that wear displayed by the scratch of epoxy filled by the metallic filling materials such as iron, copper and aluminum increased with increasing applied load. As the content of the metallic filling materials increased, wear slightly increased due to the reduction in cohesive stress inside the matrix as well as the epoxy transfer into the indenter surface might be responsible for that behavior. For epoxy filled by iron, when the magnetic field was applied to the contact area wear significantly decreased. Increasing the intensity of the magnetic field showed slight wear increase. Wear displayed by the scratch of epoxy filled by copper showed higher values than that observed for copper filled epoxy. Presence of the magnetic field might generate electric current at the contact area leading to an increase in the intensity of the electric static charge. Moreover, wear of epoxy filled by aluminum showed lower values than that observed for epoxy composites filled by copper and higher than that displayed by iron filled epoxy composites. Under the effect of magnetic field, wear significantly increased. This behavior could explained on the basis that the presence of magnetic field accompanied by the movement of the indenter in the epoxy composites generated electric current passing through the steel indenter which caused softening of the epoxy composites. In that condition removal of epoxy from the wear track was easier and epoxy transfer into the steel indenter was accelerated.
In many of mechanical drives that perform under the influence of magnetic field it is necessary to investigate the tribological performance of the sliding bearings which are probably made of polymers considering that effect. The wear of polyamide sliding against steel in the presence of magnetic field is discussed [
It is well known that a magnetic field affects polar molecules, which contain ionisable groups, by augmentation of the distance interactions and modification of the angles between bonds [
The rubbing process breaks up the polymer surface and liberates free radicals and ion radicals [
In the present work, the effect of magnetic field on the wear of epoxy composites filled by metallic particles scratched by a steel indenter is investigated.
Scratch tester is consisted of a rigid stylus mount, a diamond stylus of apex angle 90˚ and hemispherical tip as shown in
Wear displayed by the scratch of epoxy filled by iron,
Increasing the intensity of the magnetic field showed slight wear increase,
Further increase in the magnetic field showed wear increase,
increased the attractive force between the removed material and steel surface due to the presence of iron particles. This explanation was confirmed by the higher war values observed at higher iron concentration, where the highest wear was observed at 30 wt% iron concentration.
Wear displayed by the scratch of epoxy filled by copper showed higher values that that observed for iron filled epoxy,
Presence of the magnetic field might generate electric current at the contact area leading to an increase in the intensity of the electric static charge,
Wear displayed by the scratch of epoxy filled by copper under magnetic field II showed significant increase,
Further wear increase was observed in the presence of the magnetic field III,
Wear displayed by the scratch of epoxy filled by aluminum,
It is known that aluminum gains positive electric charge when sliding against steel, while epoxy gains negative charge. The resultant amount of electric charge would be relatively lower. In this condition the adherence of the removed epoxy composites into steel indenter would be weaker than that assumed for copper filled epoxy. The width of the wear scratch is much influenced by the cutting edge of the steel indenter as well as the adhesion of the filler into epoxy matrix.
Wear displayed by the scratch of epoxy filled by aluminum under magnetic field I,
Under the effect of magnetic field II,
Increasing the intensity of the magnetic field should slight decrease in wear,
The effect of magnetic field on the sliding parties with composite material based on epoxy is studied and the following remarks have been summarized:
1) Wear of epoxy composites filled by iron increased with increasing applied load. As the iron content increased wear slightly increased. When the magnetic field was applied to the contact area, wear significantly decreased. Increasing the intensity of the magnetic field showed slight wear increase. Further increase in the magnetic field showed wear increase.
2) Wear displayed by the scratch of epoxy filled by copper showed higher values than that observed for iron filled epoxy. Presence of the magnetic field might generate electric current at the contact area leading to an increase in the intensity of the electric static charge. The removed epoxy filled by copper adhered strongly into the steel surface and decrease the ability of the indenter to scratch the composites and consequently wear decreased. Wear increased as the magnetic field increased.
3) Wear displayed by the scratch of epoxy filled by aluminum showed lower values than that observed for epoxy composites filled by copper and higher than that displayed by iron filled epoxy composites. Under the effect of magnetic field, wear significantly increased. Wear increased as aluminum content increased due to two reasons: the first was the decrease of the epoxy strength and the second was the increase of the electric conducting property of the composites.
F. I.El-Zahraa,G. T.Abdel-Jaber,M. I.Khashaba,W. Y.Ali, (2016) Wear Displayed by the Scratch of Epoxy Composites Filled by Metallic Particles under the Influence of Magnetic Field. Materials Sciences and Applications,07,119-127. doi: 10.4236/msa.2016.72012