Abstract: A composite body for use, for example as a cutting tool, having a metal-carbonitride layer of titanium, zirconium or hafnium carbonitride with at least two of these metals in the lattice structure as deposited by a CVD or plasma-activated-CVD process.

Abstract: A process of forming a tool in which directly on the surface of the base body of the tool by base plasma activated chemical deposition a first PCVD layer of titanium carbide, titanium carbonitride, titanium nitride, zirconium carbonitride, and aluminum oxide is formed. Directly on this first layer by a nonplasma-activated CVD a second layer of titanium carbide, titanium carbonitride, titanium nitride, zirconium carbonitride, and aluminum oxide is formed. The steps are repeated to build up a coating so that it consists of a multiplicity of layers in a PCVD-CVD-PCVD-CVD structure.

Abstract: Composite body consisting of a hard metal, steel, ceramic, particularly sintered ceramic or cermet substrate body or a substrate body made of diamond or a nickel or cobalt-based alloy and of one or more surface layers, of which at least one, preferably the outer layer, consists of Al.sub.2 O.sub.3 with a fine crystalline structure, which has been applied by means of a plasma CVD process at substrate temperatures of 400.degree. C. to 750.degree., preferably 450.degree. C. to 550.degree., with a substrate body connected as cathode and with a plasma activation produced with a pulsed direct voltage.

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.

Abstract: Apparatus and method for corona-activated chemical vapor deposition. A substrate is positioned in a reaction vessel in all-around spaced relationship from the walls of the vessel. A cage having throughgoing perforations surrounds the substrate and is spaced from the vessel walls and the substrate. A corona discharge is generated along at least an inner surface of the cage by connecting the cage and substrate with a voltage source. A reaction gas mixture is passed through the cage and a coating is formed from the reaction gas mixture on the substrate.

Abstract: 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.

Abstract: A process for coating a basic metallic substrate with a non-metallic coating layer with a plasma-activated CVD deposition generated by applying a pulsed DC voltage between the substrate and another electrode and by maintaining a potential of residual DC voltage between pulses of the applied voltage.

Abstract: 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.

Abstract: A cutting tool, in particular of hard metal, which is coated with hard layers of titanium carbide, titanium carbonitride and/or titanium nitride and that has an outer thin layer of zirconium nitride. The thickness of this outer layer of zirconium nitride amounts to between 1 and 30%, preferably 1 to 10%, of the thickness of the base coating of titanium carbide, titanium carbonitride and/or titanium nitride.

Abstract: A coated hardmetal body comprised of a hardmetal core which contains cobalt as well as tungsten carbide and of an oxygen containing hard substance layer free of binder metal is disclosed whose hardmetal basic body has a zone at its surface which is 0.2 to 20 microns thick and which contains the CoWB phase in addition to the hardmetal components. It is of particular advantage for the binder metal free, oxygen containing hard substance layer to be composed of aluminum oxide, zirconium oxide or aluminum oxynitride. It is further provided that at least one further binder metal free hard substance layer of carbides, nitrides, borides and/or oxides is applied to the binder metal free hard oxide layer. The coated hardmetal body may advantageously be used as a cutting bit for machining metallic workpieces. The coated hardmetal body is produced by gas phase boration and subsequent hard substance coating according to the CVD process.