PVD Al2O3 coated cutting tool

US6673430B2 · kind B2 · utility

Assignees

• SANDVIK AB · SE
• Max-Planck-Gesellschaft zur Föderung der Wissenschaften e.V. · US

Inventors

• Siegfried Schiller · Dresden, DE
• Klaus Goedicke · Dresden, DE
• Fred Fietzke · Dresden, DE
• Olaf Zywitzki · Freiberg, DE
• Mats Sjostrand · Sollentuna, SE
• Bjorn Ljungberg · Stuvsta-Snättringe, SE
• Tomas Hilding · Mariefred, SE
• Viveka Alfredsson · Lund, SE

Key dates

• Filing date: May 22, 2002
• Grant date: Jan 6, 2004
• Expiry date: Aug 31, 2022

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/265
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

The present invention describes a coated cutting tool for metal machining. The coating is formed by one or more layers of refractory compounds of which at least one layer of fine-grained, crystalline &ggr;-phase alumina, Al2O3, with a grainsize less than 0.1 &mgr;m. The Al2O3 layer is deposited with a bipolar pulsed DMS technique (Dual Magnetron Sputtering) at substrate temperatures in the range 450° C. to 700° C. preferably 550° C. to 650° C., depending on the particular material of the tool body to be coated. Identification of the &ggr;-phase alumina is made by X-ray diffraction. Reflexes from the (400) and (440) planes occurring at the 2&thgr;0- angles 45.8 and 66.8 degrees when using CuK&agr; radiation identify the &ggr;-phase Al2O3. The alumina layer is also very strongly textured in the [440]-direction. The Al2O3 layer is virtually free of cracks and halogen impurities. Furthermore, the Al2O3 layer gives the cutting edge of the tool an extremely smooth surface finish.