Plasma Process and Reactor for the Thermochemical Treatment of the Surface of Metallic Pieces

A process for the thermochemical treatment of the surface of metallic pieces, in a plasma reactor (R) having a reaction chamber (RC) provided with:

• a support (S) carrying the metallic pieces;
• a system of anode and cathode having one of its electrodes associated with a high voltage pulsating DC power supply;
• an inlet of ionizable gas load;
• and an outlet, for exhaustion of gas load, characterized in that it comprises the steps of:
• a) connecting the anode to a first electrode and to a ground and connecting the cathode to the support (S), operating as the other electrode of the system of anode and cathode, and to a negative potential of the pulsating DC power supply;
• b) statically positioning the metallic pieces in the support (S) associated with the cathode in the interior of the reaction chamber (RC);
• c) surrounding the support (S) and the metallic pieces with an ionizable gas load supplied to the reaction chamber (RC) through the inlet;
• d) heating the interior of the reaction chamber (RC) to a working temperature;
• e) applying to the cathode, associated with the support (S) and with the metallic pieces, an electric discharge in order to cause the formation of a gas plasma of ions having a high kinetic energy surrounding the metallic pieces and the support (S);
• f) providing a solid precursor defined inside a tubular sputtering chamber having one end open to the interior of the reaction chamber (RC) and being associated with an electric power supply;
• g) applying a potential difference between at least one tubular sputtering chamber and the anode of the system of anode and cathode in order to provide the sputtering of the solid precursor, releasing from the latter and into the reaction chamber (RC), the alloy elements to be ionically bombarded against the surfaces of the metallic pieces negatively polarized by the pulsating DC power supply;
• and
• h) providing the exhaustion of the gas load from the interior of the reaction chamber (RC).

A reactor for the thermochemical treatment of the surface of metallic pieces, said plasma reactor (R) having a metallic housing defining, internally, a reaction chamber (RC) provided with:

• a support (S) carrying the metallic pieces;
• a system of anode and cathode associated with a pulsating DC power supply;
• an inlet of ionizable gas load;
• an inlet of liquid or gas precursor;
• an outlet of exhaustion of gas load, connected to a vacuum system;
• and a heating means mounted to the metallic housing in order to heat the interior of the reaction chamber (RC) to a working temperature, characterized in that it comprises:
• the anode connected to a first electrode and to a ground, and the cathode connected to the support (S), operating as the other electrode of the system of anode and cathode, and to a respective negative potential of the pulsating DC power supply;
• the support (S) carrying, statically, the metallic pieces and being associated with the cathode in the interior of the reaction chamber (RC);
• at least one tubular cracking chamber of a respective flow of liquid or gas precursor to be admitted therein, having at least one end open to the interior of the reaction chamber (RC) and being associated with a high voltage energy source for dissociating the molecules of the precursor and their release to the interior of the reaction chamber (RC).

A reactor for the thermochemical treatment of the surface of metallic pieces, said plasma reactor (R) having a metallic housing defining, internally, a reaction chamber (RC) provided with:

• a support (S) carrying the metallic pieces;
• a system of anode and cathode associated with a high voltage pulsating DC power supply;
• an inlet of ionizable gas load;
• a solid precursor operatively associated with the interior of the reaction chamber (RC);
• an outlet, of exhaustion of gas load, connected to a vacuum system;
• and a heating means mounted to the metallic housing, in order to heat the interior of the reaction chamber (RC) to a working temperature, characterized in that it comprises:
• the anode connected to a first electrode and to a ground, and the cathode connected to the support (S), operating as the other electrode of the system of anode and cathode, and to a negative potential of the pulsating DC power supply;
• the support (S) carrying, statically, the metallic pieces and being associated with the cathode in the interior of the reaction chamber (RC);
• at least one tubular sputtering chamber carrying the solid precursor, having one end open to the interior of the reaction chamber (RC) and being associated with an electric power supply, in order to provide the sputtering of the solid precursor and the release of its alloy elements ionically bombarded against the metallic pieces negatively polarized by the pulsating DC power supply.