Nanocrystalline Carbide Derived Carbon for Tribological Applications

1. Nanocrystalline Carbide Derived Carbon for Tribological Applications Investigators: Michael McNallan, Civil and Materials Engineering, UIC; Ali Erdemir, Argonne National Laboratory Prime Grant Support: U.S. Department of Energy • Mechanical Seals and bearings fail due to frictional heating and wear • Materials used are hard ceramics, such as SiC or WC • Friction can be reduced by coating with carbon as graphite or diamond • Graphitic coatings are not wear resistant • Diamond coatings are wear resistant, but fail by spallation or delamination from the underlying ceramic max. safe temperature SiC-SiC SiC-CDC Pump seal face temperature during dry running at 4000 rpm with and without CDC coating • Produce a low friction carbon layer by chemical conversion of the surface of the carbide • SiC(s) + 2Cl2(g)  SiCl4(g) + C(s) • At temperatures < 1000oC, carbon cannot relax into equilibrium graphitic state and remains as Carbide Derived Carbon (CDC) • CDC coating contains nano-porous amorphous C, fullerenes, and nanocrystalline diamond • CDC is low friction, wear resistant, and resistant to spallation and delamination • CDC has been produced in the laboratory • It’s structure and conversion kinetics have been characterized • Tribological performance was verified in laboratory and industrial scale pump tests with water • CDC was patented and selected for an R&D 100 Award in 2003 • CDC was Licensed to Carbide Derivative Technologies, Inc.in 2006 • Scale up to industrial production rates, characterization of process reliability and testing in specific industrial environments is the next goal.