Wear Mechanisms for Metallic Surfaces in Sliding Contact.
Annual rept. no. 3, Nov 76-Jul 77,
CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF MECHANICAL ENGINEERING
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Under certain conditions, carbontetrachloride is found to be a negative boundary lubricant gives a higher coefficient of friction than that of dry surfaces in air, while under other conditions, it lowers friction and gives a beneficial effect. Both of these situations are illustrated for heavily loaded sliding surfaces where the subsurface is undergoing gross plastic flow and an explanation is presented which appears to be consistent with all experimental facts. Carbontetrachloride is found to be more reactive chemically when the sliding surfaces are heavily strained or called under high normal and shear stresses and containing microcracks, a situation that arises when cutting at low speed. Initial results of frictional sliding under high normal pressure obtained with ATA and MoS2 lubricants clearly show that the newly developed chalcogenides are more useful in reducing wear under high normal loads than under light loads. The non-dimensional wear number Nw obtained using dimensional analysis to a limited system of wear quantity was found to be very useful parameter to the design engineer. More research is recommended towards obtaining values of Nw for a wide variety of systems. Author
- Metallurgy and Metallography
- Lubricants and Hydraulic Fluids