Patent EA-001332-B1 (EA)
Title: Sintered mechanical part with abrasionproof surface and method for producing same
IPC: G06F19/00
Filed: 1998-05-27
Abstract: 1. A mechanical part with abrasionproof surface comprisimg: a sintered metallic body (10) obtained by powder metallurgy and a cermet coating (12) enclosing the metallic body and having an outer surface, characterized in that said coating is obtained by a laser deposited fusing agent via a coaxial injection in a laser beam, said fusing agent is a mixture of metallic powders and ceramic powders and comprises spherically-shaped carbides, wherein said mixture is for forming said coating, in which a porosity is absent, said coating is metallurgically bound with the metallic body (10), has a thickness ranging between 10 μm and 1 mm and comprises spherically-shaped carbides in a metallic matrix. 2. The mechanical part (4) according to claim 1, characterized in said sermet coating (12) comprises carbides (16) in said metallic matrix, said carbides are selected from the group comprising tungsten, titanium and boron carbides. 3. The mechanical part (4) according to claim 2, characterized in that said carbides are tungsten carbides (16). 4. The mechanical part (4) according to claim 2 or 3, characterized in that said metallic matrix comprises, at least, one metal selected from the group comprising nickel, chromium and cobalt. 5. The mechanical part (4) according to claims 2 to 4, characterized in that said metallic matrix comprises nickel, chromium and cobalt. 6. The mechanical part (4) according to claim 2 to 5, characterized in that said metallic matrix is a Ni-9%Cr-Co matrix. 7. The mechanical part (4) according to claim 2 to 6, characterized in that said coating (12) comprises 65% of tungsten (16) carbide by weight  8. A method for producing a sintered mechanical part with an abrasionproof surface, characterized in that comprises the steps of: a) producing a sintered mechanical part by said powder metallurgy; b) applying a sermet coating (12) on the outer surface of said part using a laser process, said laser process comprises the steps of: directing a laser beam (22) to the outer surface of a part (4), wherein said laser beam (22) produces a certain temperature; injecting via a laser beam (22) a fluxing agent which is a mixture of ceramic powders comprising spherically-shaped carbides, and metallic powders designed to form a sermet coating (12), the fusion temperature of the ceramic powders is higher than that of the laser beam, while the fusion temperature of the metallic powders is lower than that of the laser beam, so that the laser beam fuses the metallic powder from the powder mixturewhich is applied on the outer surface of the part (4); wherein the powder mixture is fed by an injection in a laser beam 22) via a coaxial nozzle (2), which is crossed by the laser beam (22) in its center, wherein said nozzle (2) allows to feed the powder mixture and its injection by the laser beam (22) and displacing the laser beam relative to the mechanical part so that to move the outer surface of the metallic body (10) and to form sermet coating. 9. The method according to claim 8, characterized in that the laser beam is fixed, and the mechanical part is installed on a movable table (30) enabling to displace relative to said laser beam. 10. The method according to claim 8 or 9, characterized in that the sermet coating (12) comprises tungsten carbide in said metallic matrix. 11. The method according to claim 8 to 10, characterized in that the ceramic powder is a tungsten carbide powder and in that the metallic powder is a powder, comprising, at least, one metal selected from the group comprising nickel, chromium and cobalt. 12. The method according to claim 11, characterized in that the ceramic powder is a a Ni-9%Cr-Co powder. 13. A peeling device (4) comprising the metallic body (10) with a bottom plane adapted for mounting a peeling lever at its end, and a working abrasionproof surface, characterized in that  the metallic body (10) is a sintered metallic body, obtained by the powder metallurgy; and the working abrationproof surface comprises the sermet coating (12), enclosing the metallic body (10), wherein said coating is metallurgically bound with the metallic body (10), and has a thickness ranging between 10 (m and 1 mm. 14. The peeling device according to claim 13, characterized in that the sermet coating (12) is a coating obtained by a laser deposition on said metallic body (10).