Nanostructured Carbon Coatings

Abstract

This paper provides a review with 51 refs. of nanocryst. and nanostructured carbon coatings and explores a very broad range of potentially important carbon nanostructures that may be used in future technologies. A new method for the synthesis of nanostructured carbon coatings on the surface of SiC and other metal carbides is described. This method is accomplished through the extn. of metals from carbides by supercrit. water or halogens in a high temp. reactor. This is a versatile technol. because a variety of carbon structures can be obtained on the surface of carbides in the same reactor. Not only simple shapes or fibers, but also powders, whiskers and components with complex shapes and surface morphologies can be coated. This technol. allows for the control of coating growth on the at. level, monolayer by monolayer, with high accuracy and controlled structures. Ordered and disordered graphite, nanoporous carbon (sp. surface area of 1000 m2/g and more) and hard carbon can be formed depending on the temp. and gas compn. These carbon coatings can be used as tribol. coatings having a low-friction coeff. for a variety of applications, from heavy-load bearings to nanocoatings for MEMS; protective coating for sensors and tools, intermediate thin films for further CVD deposition of diamond, weak coatings on SiC reinforcements for composite materials, coatings on SiC powders for improved sinterability, catalyst supports, mol. membranes for sensors, etc. The structure and properties of carbon coatings obtained on the surface of SiC have been investigated using an array of anal. techniques. [on SciFinder(R)]