PVD Al2O3 coated cutting tool

US6210726A · kind A · utility

Assignee

• SANDVIK AB · SE

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: Nov 6, 1998
• Grant date: Apr 3, 2001
• Expiry date: Nov 6, 2018

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 a refractory compound of which at least one layer of fine-grained, crystalline .gamma.-phase alumina, Al.sub.2 O.sub.3, with a grain size of less than 0.1 .mu.m. The Al.sub.2 O.sub.3 layer is deposited with a bipolar pulsed DMS technique (Dual Magnetron Sputtering) at substrate temperatures in the range 450.degree. C. to 700.degree. C., preferably 550.degree. C. to 650.degree. C., depending on the particular material of the tool body to be coated. Identification of the .gamma.-phase alumina is made by X-ray diffraction. Reflexes from the (400) and (440) planes occurring at the 2.theta.-angles 45.8 and 66.8 degrees when using Cu.sub..kappa..alpha. radiation identify the .gamma.-phase Al.sub.2 O.sub.3. The alumina layer is also very strongly textured in the [(440)]-direction. The Al.sub.2 O.sub.3 layer is virtually free of cracks and halogen impurities. Furthermore, the Al.sub.2 O.sub.3 layer gives the cutting edge of the tool an extremely smooth surface finish.