Method of and apparatus for coating shaped parts by cathodic atomization

Claim 3

Apparatus of coating a part by cathodic atomization of target material, the part having a three-dimensional surface to be coated, comprising: two, facing cathodic atomization devices for receiving the part to be coated in a discharge space therebetween, each cathodic atomization device having a target of the same material with a surface delimiting the discharge space, a cathode arrangement for producing a plasma cloud of the target material in the discharge space, and magnetic means producing a magnetic field which closes on the target for concentrating the plasma cloud of the target material in a zone at the target surface delimiting the discharge space; and means for applying a voltage which is negative with respect to ground to the part to be coated in the discharge space sufficient to facilitate at least touching of the plasma clouds of the target material from the cathodic atomization devices at the place in the discharge space where the part to be coated will be received.

Claim 4

Apparatus of coating a part by cathodic atomization of target material, the part having a three-dimensional surface to be coated, comprising: two, facing cathodic atomization devices for receiving the part to be coated in a discharge space therebetween, each cathodic atomization device having a target of the same material with a surface delimiting the discharge space, a cathode arrangement for producing a plasma cloud of the target material in the discharge space, and magnetic means producing a magnetic field which closes on the target for concentrating the plasma cloud of the target material in a zone at the target surface delimiting the discharge space; and means for applying a voltage which is negative with respect to ground to the part to be coated in the discharge space sufficient to facilitate at least touching of the plasma clouds of the target material from the cathodic atomization devices at the place in the discharge space where the part to be coated will be received.

Claim 5

The method of claim 1, wherein providing the cathodic atomization devices comprises providing at least one thereof with operating parameters so selected that the plasma clouds of the two cathodic atomization devices would overlap at least partially even when no part has been received in the discharge space therebetween and wherein applying the voltage which is negative with respect to ground to the part comprises so applying at least 10 V.

Claim 6

The apparatus of claim 2, wherein the cathodic atomization devices comprises at least one thereof adapted and configured for operating parameters so selected that the plasma clouds of the two cathodic atomization devices would overlap at least partially even when no part has been received in the discharge space therebetween and wherein the means for applying the voltage which is negative with respect to ground to the part comprises means for so applying at least 10 V.

Claim 7

The method of claim 1, wherein providing the cathodic atomization devices comprises providing the cathode arrangement of each thereof with a discharge voltage of from about 200 V to about 1000 V in a way for an atomization power of from about 5 to about 30 watts/cm 2 at the surface of the target, providing the target surfaces delimiting the discharge space with a spacing of from about 80 mm to about 200 mm, providing the magnetic means with a magnetic field strength of from about 150 Oersteds to about 350 Oersteds, and wherein applying a voltage comprises applying from about -50 V to about -500 V to the part; and further comprising providing a pressure in the discharge space of from about 1×10 -3 mbars to about 5×10 -2 mbars and a temperature to the part of from about 150° C. to about 500° C., whereby the method is adapted for producing hard coatings, and particularly nitride coatings.

Claim 8

The apparatus of claim 2, wherein, in the cathodic atomization devices, the cathode arrangement of each thereof has a discharge voltage of from about 200 V to about 1000 V in a way for an atomization power of from about 5 to about 30 watts/cm 2 at the surface of the target, the target surfaces delimiting the discharge space have a spacing of from about 80 mm to about 200 mm, the magnetic means has a magnetic field strength of from about 150 Oersteds, to about 350 Oersteds, and wherein the means for applying a voltage applies from about -50 V to about--500 V to the part; and further comprising means for providing a pressure in the discharge space of from about 1×10 -3 mbars to about 5×10 -2 mbars and a temperature to the part of from about 150° C. to about 500° C., whereby the apparatus is adapted for producing hard coatings, and particularly nitride coatings.

Claim 9

The method of claim 1, wherein providing the cathodic atomization devices comprises providing the cathode arrangement of each thereof with a discharge voltage of from about 200 V to about 1000 V in a way for an atomization power of from about 10 to about 15 watts/cm 2 at the surface of the target, providing the target surfaces delimiting the discharge space with a spacing of from about 100 mm to about 150 mm, providing the magnetic means with a magnetic field strength of from about 200 Oersteds to about 250 Oersteds, and wherein applying a voltage comprises applying from about -50 V to about -500 V to the part; and further comprising providing a pressure in the discharge space of from about 5×10 -3 mbars to about 2×10 -2 mbars and a temperature to the part of from about 250° C. to about 300° C., whereby the method is adapted for producing hard coatings, and particularly nitride coatings.

Claim 10

The method of claim 7, wherein providing the pressure in the discharge space comprises providing the same with an atmosphere of an inert gas and nitrogen having a partial pressure of from about 4×10 -4 mbars to about 8×10 -4 mbars.

Claim 11

The method of claim 8 wherein the inert gas is argon.

Claim 12

The apparatus of claim 2, wherein the surfaces of the targets are curved in a manner to delimit the discharge space between the target surfaces as at least a sector of substantially cylindrical section.

Claim 13

The apparatus of claim 10, wherein the surfaces of both targets are curved and arranged to delimit an annular, substantially-cylindrical section sector to the discharge space therebetween, and further comprising a cylindrical holder for holding the part to be coated and at least one other part to be coated, the holder being rotatable through the annular substantially-cylindrical section sector of the discharge space delimited by the target surfaces, thereby substantially enclosing at least the target of one of the cathodic atomization devices, and having at least a portion which is removable to allow removal of the target substantially enclosed thereby.