Process for deposition of a protective coating based on amorphous diamond pseudocarbon or on modified silicon carbide

摘要

Process for depositing, on at least one article, a protective coating based on amorphous diamond pseudocarbon or on silicon carbide modified by the so-called "plasma-assisted CVD" technique by which a carbonaceous gas containing especially one or more hydrocarbons, optionally silicon-treated, is introduced together with, if appropriate, doping agents such as nitrogen, fluorine or boron or else metals such as titanium or silver or aluminium, by simultaneous cathode sputtering or in an organometallic form into a vacuum chamber containing a metal support connected to a powerful DC or AC generator operating in the radio-frequency or microwave range and on which the article to be coated is situated, and an electrical discharge is maintained inside the chamber so as to raise the temperature of the article to a value of 200 to 250 DEG C and in power and pressure conditions permitting the physical and chemical excitation of the gas and its ionisation so as to cause the deposition on the article of a protective coating based on amorphous diamond pseudo carbon or on modified silicon carbide, a process characterised in that a pulsation is superposed on the current supplied by the generator, so that the plasma is activated only during a cyclic fraction of the period of treatment.