The Wear of Aluminium Bronze on Steel in Aviation Kerosene

Abstract

The ability of lubricants of the same viscosity to provide adequate lubrication for surfaces in relative motion (lubricity) ,can widely vary. Under boundary lubrication conditions fluid films of poor lubricity, can break down giving rise to contact. Contact results in wear, which under severe conditions, can damage the moving components beyond repair. The special case of an aircraft, axialpiston, fuel pump has been studied for this project. The pump consists of steel pistons running in cadmium pleted aluminium bronze bores lubricated by aviation kerosene of variable lubricity. Seizure occurs in the pump if the fuel lubricity is poor but protection is afforded by the inclusion of an additive in the fuel. The latter is not universally accepted by the operating companies so the project not only aims to determine the mechanism of failure of the pump but also the mechanism of protection by the additive. Boundary lubricated wear was simulated using a flat-faced pin-on- disk machine and friction and wear rate measured for bronze sliding against steel for various fuels. Wear rates of between 10-9 and 10-6mm3 mm-1 were found and, although the additive has an initial pro-wear effect, very low wear could be obtained when the additive was present. The wear pins and disks, samples from a pump simulation rig (the Lucas two-piston rig) and from 'in service' pumps were analysed. The physical analytical techniques used, in this part of the work, included scanning and transmission electron microscopy, X-ray powder diffraction, electron probe microanalysis and Auger spectroscopy. This analysis has shown that the aluminium content, of the bronze, plays an important role, in the seizure mechanism, by diffusion to the steel surface. The additive prevents seizure by preferential corrosion of aluminium from the bronze, thus preventing its transfer to the steel. Similarities between laboratory, intermediate test rig and 'in service' experience have been found by using this analytical approach. Finally a new theory has been instigated to predict wear rates under conditions of boundary lubrication where oxidation is occurring.

Publication DOI: https://doi.org/10.48780/publications.aston.ac.uk.00011985
Divisions: College of Engineering & Physical Sciences
Additional Information: Copyright © Poole, William, 1979. Poole, William asserts their moral right to be identified as the author of this thesis. This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with its author and that no quotation from the thesis and no information derived from it may be published without appropriate permission or acknowledgement. If you have discovered material in Aston Publications Explorer which is unlawful e.g. breaches copyright, (either yours or that of a third party) or any other law, including but not limited to those relating to patent, trademark, confidentiality, data protection, obscenity, defamation, libel, then please read our Takedown Policy and contact the service immediately.
Institution: Aston University
Uncontrolled Keywords: wear,aluminium bronze,steel,aviation kerosene
Last Modified: 29 Jan 2025 16:54
Date Deposited: 13 Jan 2011 11:03
Completed Date: 1979-03
Authors: Poole, William

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