Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.

Gunter Hotzsch

Klaus Goedicke

Siegfried Schiller

Fred Fietzke

Olaf Zywitzki

Jonathan Reschke

Wolfgang Hempel

Compound body of a vacuum coated sintered material and a process for its production. Such compound bodies, when coated in a known manner, have a carrier of sintered material coated with a layer that is thermally, mechanically and chemically unstable, with their surface showings cracks and being partially porous. These shortcomings are overcome via an improved eco-friendly vacuum deposition process, wherein at least one layer of a material, having an outer layer of Al.sub.2 O.sub.3, is applied to the carrier of sintered material at a maximum of 800.degree. C., with this layer being completely crystalline and comprised of an .alpha.Al.sub.2 O.sub..sub.3 phase and possibly of a .gamma.Al.sub.2 O.sub.3 phase with a (440) texture, having a compressive stress of at least 1 GPa and a hardness of at least 20 GPa, with the Al.sub.2 O.sub.3 layer being deposited via reactive magnetron sputtering, wherein the magnetrons are pulse driven, the pulse frequency lies between 20 and 100 Khz and the deposition rate is at least 1 nm/s, with the resulting compound bodies being utilized for cutting treatments, particularly as cemented carbide inserts.

Compound body of vacuum-coated sintered material and process for its

Vacuum coated compound body and a process for its production. Such compound bodies, when coated in a known manner, have a carrier of a metal or of an alloy, a layer that is thermally, mechanically and chemically unstable, with their surface showing cracks and being partially porous. These shortcomings are overcome via an improved eco-friendly vacuum deposition process wherein at least one layer of a material having an outer layer is of Al.sub.2 O.sub.3, is applied to the metal or alloy carrier at a maximum of 700.degree. C., with this layer being completely crystalline and comprised of an .alpha.Al.sub.2 O.sub.3 phase and possibly of a .gamma.Al.sub.2 O.sub.3 phase with a (440) texture, having a compressive stress of at least 1 Gpa and a hardness of at least 20 Gpa, with the Al.sub.2 O.sub.3 layer being deposited via reactive magnetron sputtering, wherein the magnetrons are pulse powered, the pulse frequency lies between 20 and 100 Khz, and the deposition rate is at least 1 nm/s, with the compound bodies being utilized for cutting treatments, particularly as drills, milling cutters, reamers, broaches or saw blades.

Vacuum-coated compound body and process for its production

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Dresden, Germany

Gunter Hotzsch