Loh Nee Lam

Materials degradation and its control by surface engineering

Mechanisms of Materials Degradation: Mechanical Causes of Materials Degradation Chemical Causes of Materials Degradation Materials Degradation Induced by Heat and Other Forms of Energy Duplex Causes of Materials Degradation Surface Engineering: Discrete Coatings Integral Coatings and Modified Surface Layers Characterization of Surface Coatings Application of Control Techniques: Control of Materials Degradation Financial and Industrial Aspects of Materials Degradation and Its Control.

Lubrication of stellite at ambient and elevated temperatures by transfer films from a graphite slider

The lubrication of stellite in dry sliding by a graphite rod loaded against the wear track on the stellite surface was investigated. Stellite sliding against stellite was studied with a pin-on-disc machine which was also fitted with a spring loaded graphite pin. Tests were performed in air from ambient temperature to 400 °C for varying sliding speed and load. It was found that the wear of the stellite pin was reduced by approximately a factor of 10 compared to unlubricated sliding when the graphite pin was present. The wear coefficient of the graphite pin was similar in magnitude to the wear coefficient of the lubricated stellite. The friction coefficient of the stellite was also lowered significantly, but the overall frictional energy dissipation of both the stellite and graphite specimens was only marginally less than dry sliding under the same conditions. Surface analysis and microscopy of worn specimens revealed extensive deposition of graphite films on both the stellite pin and disc.