Tribological evaluation of unlubricated and marginally lubricated bearing materialsReport as inadecuate






Author: Sarma Volety

Source: https://core.ac.uk/

This thesis presents friction and wear rate measurements of the copper based bearing materials used in thrust bearing of aircraft fuel pumps. Highly detailed friction and wear data was collected from 20% and 30% lead in bronze (leaded bronze) substrates and 10% indium in lead (lead/indium) coated leaded bronze substrates in unlubricated and marginally lubricated conditions. Measurements were made under a wide range of load and speed using a thrust washer test apparatus and pin on disc test equipment


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TRIBOLOGICAL EVALUATION OF UNLUBRICATED AND MARGINALLY LUBRICATED BEARING MATERIALS Sarma Volety PhD Thesis TRIBOLOGICAL EVALUATION OF UNLUBRICATED AND MARGINALLY LUBRICATED BEARING MATERIALS BY BANGARESWARA SARMA VOLETY B.Tech., M.Sc. A thesis submitted in partial fulfilment for the requirements of the degree of DOCTOR OF PHILOSOPHY at the University of Central Lancashire in collaboration with Goodrich Aero Engine Controls October 2010 Declaration DECLARATION I declare that while registered with the University of Central Lancashire for the degree of the Doctor of Philosophy, I have not been a registered candidate or enrolled student for another award with the institute or with any other academic or professional institution during the research programme.
No portion of this work referred to in this thesis has been submitted in support of any application for another degree or qualification of any other University or Institution of learning. Signed .
………………………………………. V.
B.
Sarma ii Abstract ABSTRACT This thesis presents friction and wear rate measurements of the copper based bearing materials used in thrust bearing of aircraft fuel pumps.
Highly detailed friction and wear data was collected from 20% and 30% lead in bronze (leaded bronze) substrates and 10% indium in lead (lead-indium) coated leaded bronze substrates in unlubricated and marginally lubricated conditions.
Measurements were made under a wide range of load and speed using a thrust washer test apparatus and pin on disc test equipment. During the running-in period in unlubricated test conditions, the substrate friction and wear rate was found to depend on the percentage of lead content and its microstructure.
High friction and wear rates were observed for lead-indium coatings due to the high contribution of ploughing and transfer of coating to the counterface surface.
The coefficient of friction for lead-indium coatings appeared to depend on their thickness.
During steady state conditions, the friction coefficient of both substrates and coatings remained constant and thin coatings had lower friction than uncoated and thick coated substrate materials.
In marginally lubricated test conditions, the fluid film limited metal to metal contact for a limited time interval and the friction coefficient observed was low.
When the fluid was removed from the contact due to the evaporation or flow, the situation became dry test and the test results were similar to ....





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