THIN FILM COATING OF BLADES

摘要

Disclosed is a process for forming a razor blade comprising the steps of:(a) providing a substrate; (b) forming a wedge-shaped sharpened edge on said substrate that has an included angle of less than thirty degrees and a tip radius of less than 1000 angstroms; (c) placing said substrate in a vacuum chamber;(d) placing a first solid target (preferably a metal such as chromium or its alloy) in said vacuum chamber;(e) providing a gas to be ionized in said vacuum chamber;(f) generating ions from said first solid target by applying a negative voltage to said first solid target in pulses (wherein the pulses of step are provided in such a way that a power density is developed in a pulse in the range of 0.1 kW/cm2 to 20 kW/cm2), said ions forming a thin film coating on the wedge-shaped sharpened edge on the substrate and optionally pivoting said substrate about an axis; and(g) generating additional ions from said first solid target by applying a second lower negative voltage to said first solid target in pulses, said ions forming a thin film coating on the wedge-shaped sharpened edge on the substrate.The ion bombardment has the effect of incorporation of the etching metal, i.e., chromium, into the blade edge to depths of about 30 nm. Such incorporation leads to better adhesion of the coating to the blade edge via a mechanism of epitaxial coating growth localized on individual grains of the blade edge. Blades are then coated with a thin film coating of CrN in an argon and nitrogen environment, an optional coating of polytetraflouroethylene (PTFE) telomer may be applied to the CrN coated edges of the blades.