Fried. Krupp Gesellschaft MIT Beschrankter Haftung

Fried Krupp

Daimler-benz Ag

Josef Blum

Hendrikus Van Den Berg

Udo Konig

Ralf Tabersky

Paul Pant

Johannes Jachowski

Heinz Lamm

Alfred Sprang

Helmut Klasing

A tool having an extended service lift and including a hard metal body, and at least one surface layer composed of at least one hard substance selected from the group consisting of carbides, nitrides, and carbonitrides of titanium and zirconium, and having a chlorine content ranging from a finite amount up to 4 mass percent, the tool being produced by plasma-activated CVD process including: a. positioning the hard metal body in a CVD chamber having means for supplying direct voltage thereto, the hard metal body being connected to the direct voltage supplying means as a cathode thereof, b. introducing into the CVD chamber a reactive gas mixture including a nitrogen-containing substance, a carbon-containing substance, and at least one compound containing at least one of titanium and zirconium, and c. exciting plasma formation at the hard metal body and coating same by chemical vapor deposition by applying a pulsed direct voltage and a residual direct voltage thereto, the residual direct voltage having a magnitude which is at least equal to the lowest ionization potential of any gas in the reactive gas mixture but does not exceed 50% of the maximum value of the pulsed direct voltage.

Tool produced by a plasma-activated CVD process

A plasma-activated CVD process provides improved adhesion of the coated surface layers and employs, as the plasma exciting source, a pulsed direct voltage and a residual direct voltage which remains during the pulse intervals. The residual direct voltage is equal to or greater than the lowest ionization potential of the gases participating in the CVD process, but is no more than 50% of the maximum value of the pulsed direct voltage. The total thickness of the layer(s) does not exceed 30 .mu.m and the temperature of the basic tool body during the coating process is reduced, compared to prior art plasma CVD processes, and ranges from between 400.degree. to 800.degree. C., and is preferably kept below 600.degree. C.

Plasma CVD process for coating a basic tool body

A wear resistant compound body is disclosed which is comprised of a metallic basic material and has a wear resistant zone which includes hard substance and/or hard metal particles in addition to the basic material. The basic material is composed of

Wear resistant compound body

A sintered hard metal sealing strip particularly for constituting a radial seal in a rotary internal combustion engine, includes a hollow body with longitudinal ends each closed off by a sintered hard metal end face forming part of the hollow body.

Sealing strip particularly for rotary engines

Growing community of inventors

Essen, Germany

Josef Blum