Copper-Alumina Composite Materials as a Tribological Element of Foil Bearings

摘要

Foil bearings are particularly attractive for systems where conventional oil-lubricated or rolling element bearings have proved unsuitable due to temperature, rotational speed, working fluid, etc. There are numerous possible applications for foil bearings, including aircraft gas turbine engines, auxiliary power units, microturbines, pumps, compressors, cryogenic turboexpanders and turbochargers. To expand the range of their practical implementations several investigations of materials likely to fulfill many different requirements have been performed. With respect to the application as top foils both tribological properties (friction coefficient and wear resistance) and thermal properties (thermal conductivity) are demanded. One possible solution in the case of such complex systems could be using composite materials. The results of performed technological tests aimed at producing copper-alumina composites are presented in this study. Microstructural investigations, tribological test results and thermal properties measurements of Cu-Al_2O_3 composites for a different volume fraction of the ceramic phase (2.0, 5.0 and 10.0 vol.%) are compared.