Controlling diamond film surfaces

Abstract

A method of preparing a low friction diamond surface comprises removing asperities from a surface of a polycrystalline diamond film disposed on a substrate, e.g., by removing not more than about 500 nm (e.g., not more than about 100 nm, 50 nm, 25 nm, or 10 nm) of diamond, on average, from the surface of the film. The removal step can be controlled to preserve depressions in the surface, which can provide useful properties, such as reservoirs for lubrication, which contribute to the low friction properties of diamond films prepared by the methods of the present invention. The diamond films of the invention preferably have an average grain size of about 2000 nm or less (e.g., less than or equal to about 1000 nm, 100 nm, 50 nm, 20 nm or 10 nm), and preferably include fewer than about 2000 asperities per square millimeter of diamond surface, or about 4/mm on a linear basis, as determined using a 2 μm diameter profilometer stylus tip.

Dependencies are inferred from the claim text.