The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 31, 2000
Filed:
Nov. 23, 1998
Christine Taschner, Dresden, DE;
Ingolf Endler, Dresden, DE;
Albrecht Leonhardt, Dresden, DE;
Bjorn Ljungberg, Enskede, SE;
Mats Sjostrand, Kista, SE;
Sandvik AB, Sandviken, SE;
Abstract
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.