Composite body, its use and a process for its production
AssigneeWidia GmbH
InventorsHendrikus van den Berg, Ralf Tabersky, Udo Konig, Norbert Reiter
Life of this patent
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Abstract
A composite body, especially for use as a cutting tool, for the lining of combustion chambers or for movable parts intended to have low wear which has a substrate of hard metal, steel, cermet or nickel or cobalt alloy. The substrate is provided with at least one fine-crystalline alpha-Al.sub.2 O.sub.3 layer deposited by plasma activated CVD at 400.degree. to 750.degree. C. With plasma activation by pulsed direct voltage with the substrate connected as the cathode.
Claims22
A composite body, comprising:
- a substrate body selected from the group which consists of a hard metal body, a steel body, a cermet body, a nickel alloy body and a cobalt alloy body, wherein said substrate body is provided with
- at least one fine-crystalline .alpha.-Al.sub.2 O.sub.3 layer deposited thereon by plasma-activated chemical vapor deposition at a temperature of 400.degree. to 750.degree. C. with plasma activation by pulsed direct voltage with said substrate body connected as a cathode, said fine-crystalline .alpha.-Al.sub.2 O.sub.3 layer having a diffraction line upon X-ray diffraction analysis with CuK.sub..alpha. X-rays with a half-width value at least three times greater than a half-width value of a corresponding line measured on a powdered compact body of .alpha.-Al.sub.2 O.sub.3 and an .alpha.-Al.sub.2 O.sub.3 deposited by chemical vapor deposition at 1000.degree. to 1100.degree. C.
A method of protecting a surface selected from the group which consists of a surface of a cutting tool, a surface of a combustion chamber, a surface of a body in frictional contact with another body and a surface of a casting mold which comprises applying to said surface at least one finecrystalline .alpha.-Al.sub.2 O.sub.3 layer on said substrate by plasma-activated chemical vapor deposition at a temperature of 400.degree. to 750.degree. C. with plasma activation by pulsed direct voltage with said substrate connected as a cathode, so that said fine-crystalline .alpha.-Al.sub.2 O.sub.3 layer has a diffraction line upon X-ray diffraction analysis with CuK.alpha. X-rays with a half-width value at least three times greater than a half-width value of a corresponding line measured on a powdered compact body of .alpha.-Al.sub.2 O.sub.3 and an .alpha.-Al.sub.2 O.sub.3 deposited by chemical vapor deposition at 1000.degree. to 1100.degree. C.
A process for applying a surface coating of fine-crystalline .alpha.-Al.sub.2 O.sub.3 on a substrate body selected from the group which consists of a hard metal body, a steel body, a cermet body, a nickel alloy body and a cobalt alloy body, comprising depositing at least one fine-crystalline .alpha.-Al.sub.2 O.sub.3 layer on said substrate by plasma-activated chemical vapor deposition at a temperature of 400.degree. to 750.degree. C. with plasma activation by pulsed direct voltage with said substrate connected as a cathode, so that said finecrystalline .alpha.-Al.sub.2 O.sub.3 layer has a diffraction line upon X-ray diffraction analysis with CuK.sub..alpha. X-rays with a half-width value at least three times greater than a half-width value of a corresponding line measured on a powdered compact body of .alpha.-Al.sub.2 O.sub.3 and an .alpha.-Al.sub.2 O.sub.3 deposited by chemical vapor deposition at 1000.degree. to 1100.degree. C.
Dependencies are inferred from the claim text.