Method for depositing a hard protective coating
First Claim
1. Method of depositing on at least one part a protective coating which is substantially hydrogen-free, has a predominately tetrahedral structure and is based on carbon and nitrogen, on titanium, nitrogen, and carbon, or on boron and nitrogen, using plasma enhanced chemical vapor deposition by introducing a precursor gas containing elements to be deposited into a vacuum chamber containing a metal support connected to a power generator producing direct or alternating current and operating in the radio-frequency or microwave range and on which the part to be coated is placed, and maintaining an electrical discharge inside the chamber so as to increase the temperature of the part to a value of between 150°
- and 400°
C., and at power and pressure conditions at which the precursor gas is excited physically and chemically and ionized in the form of plasma so as to cause said protective coating to be deposited on the part by ion bombardment, characterized in that the precursor gas contains nitrogen, a gas providing dissociated hydrogen within the plasma and boron or one of its compounds;
in that added to the precursor gas is between 10 and 70% of a mixture of helium and argon or between 10 and 70% neon of which the role is to excite and dissociate the nitrogen and hydrogen simultaneously; and
in that the energy supplied to each atom of the precursor gas is selected so that the coating possesses a maximum number of tetrahedral structures at the expense of hexagonal structures.
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Accused Products
Abstract
A method for depositing a hard protective coating on at least one part, wherein 10-70% of nitrogen combined with 10-70% of a mixture of helium and argon or 10-70% of neon for strongly exciting and dissociating the nitrogen and hydrogen, is added to a precursor gas, and the energy delivered to each atom of the precursor gas is selected so as to achieve so-called "Lifschitz" conditions which define the energy range in which a maximum number of diamond-like tetrahedral structures are produced instead of graphite structures.
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Citations
13 Claims
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1. Method of depositing on at least one part a protective coating which is substantially hydrogen-free, has a predominately tetrahedral structure and is based on carbon and nitrogen, on titanium, nitrogen, and carbon, or on boron and nitrogen, using plasma enhanced chemical vapor deposition by introducing a precursor gas containing elements to be deposited into a vacuum chamber containing a metal support connected to a power generator producing direct or alternating current and operating in the radio-frequency or microwave range and on which the part to be coated is placed, and maintaining an electrical discharge inside the chamber so as to increase the temperature of the part to a value of between 150°
- and 400°
C., and at power and pressure conditions at which the precursor gas is excited physically and chemically and ionized in the form of plasma so as to cause said protective coating to be deposited on the part by ion bombardment, characterized in that the precursor gas contains nitrogen, a gas providing dissociated hydrogen within the plasma and boron or one of its compounds;
in that added to the precursor gas is between 10 and 70% of a mixture of helium and argon or between 10 and 70% neon of which the role is to excite and dissociate the nitrogen and hydrogen simultaneously; and
in that the energy supplied to each atom of the precursor gas is selected so that the coating possesses a maximum number of tetrahedral structures at the expense of hexagonal structures. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- and 400°
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9. Method of depositing on at least one part a protective coating which is substantially hydrogen-free, has a predominately tetrahedral structure and is based on carbon and nitrogen, on titanium, nitrogen and carbon or on boron and nitrogen, using physical vapor deposition which may or may not be enhanced by a magnetic field, by introducing a sputtering gas containing elements to be deposited into a vacuum chamber containing a metal support connected to a power generator producing direct or alternating current and operating in the radio-frequency or microwave range and on which is placed the part to be coated, creating an electrical discharge so as to physically and chemically excite the sputtering gas and ionize it in the form of plasma, providing a target which is made from a material containing elements to be deposited in the vacuum chamber and supplying said target with direct or radio-frequency current so as to cause said protective coating to be deposited on the part, characterized in that the sputtering gas contains nitrogen, a gas providing dissociated hydrogen within the plasma and boron or one of its compounds when boron is not present in the material constituting the target;
- in that added to the sputtering gas is between 10 and 70% of a mixture of helium and argon or between 10 and 70% neon of which the role is to excite and dissociate the nitrogen and hydrogen simultaneously; and
in that the current supplying the support bearing the part is selected so as to give rise to radio-frequency polarization of the support, so that the coating possesses a maximum number of tetrahedral structures at the expense of hexagonal structures. - View Dependent Claims (10, 11, 12, 13)
- in that added to the sputtering gas is between 10 and 70% of a mixture of helium and argon or between 10 and 70% neon of which the role is to excite and dissociate the nitrogen and hydrogen simultaneously; and
Specification