Widia Gmbh

Sandvik Ab

Albrecht Leonhardt

Ingolf Endler

Volkmar Sottke

Udo K&ouml;nig

Bjorn Ljungberg

Hendrikus Van Den Berg

Mats E Sjostrand

Christine Taschner

The invention relates to a tool, especially a cutting insert for cutting metallic materials, which consist of a hard metal, cermet ceramics or steel base, especially of a high speed steel base, and at least one layer deposited thereon. The single layer, or in the case of several layers the outer layer or the layer underneath the outer layer, contains molybdenum sulfide. The aim of the invention is to improve the resistance to wear of the friction-reducing, molybdenum sulfide containing layer even at high pressures. To this end, the molybdenum sulfide containing layer consists of an alternating sequence of two layer that are different from one another. The first layer contains 51 to 100% by weight of metallic molybdenum and the second layer contains 21 to 100% by weight of MoS which substantially consists of hexagonal crystals that are at least substantially oriented in a plane parallel to the tool surface.

Tool with a molybdenum sulfide containing coating and method for its production

The invention relates to a tool, especially a cutting insert for cutting metallic materials, consisting of a hard metal, cermet, ceramic or steel base body and at least one coating deposited thereon. This single coating or in the event that there are several layers, the outer layer or the layer below the outer layer, consists essentially of molybdenum sulphide. The invention also relates to a method for producing the molybdenum sulphide coating by chemical vapour deposition. According to the invention, the molybdenum sulphide coating contains a mixture of the sulphide phases MoS and Mo S with an essentially random orientation (isotropic orientation) of the phase crystals. The coating is applied by means of a chemical vapour deposition procedure.

Tool with a molybdenum sulfide coating and method for producing the same

A method for depositing refractory alumina (A.sub.2 O.sub.3) thin layers on cutting tools made of cemented carbide, cermet, ceramics or high speed steel is disclosed. The present method is a Plasma Activated Chemical Vapor Deposition (PACVD) process in which the plasma is produced by applying a bipolar pulsed DC voltage across two electrodes to which the tool substrates to be coated are fixtured and electrically connected. In contrast to prior art methods, built-up electrical charge on non-conducting surfaces is suppressed and hence, no arcing occurs on said surfaces. This will permit stable, long-term processing, With the present method, high-quality coatings of either single phase gamma-Al.sub.2 O.sub.3 or of a mixture of gamma- and alpha-Al.sub.2 O.sub.3 phases can be deposited on cutting tools at deposition temperatures as low as 500.degree. C. When coated cemented carbide tools according to the invention are used in the machining of steel or cast iron, several important improvements to prior art produced Al.sub.2 O.sub.3 -coated tools have been observed.

Method for depositing fine-grained alumina coatings on cutting tools

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Dresden, Germany

Albrecht Leonhardt