| 摘要 |
The present invention relates to a method of depositing a crystalline alpha -Al2O3-layer onto a cutting tool insert by Chemical Vapour Deposition at a temperature of 625-800 DEG C. The method comprises the following steps depositing a 0.1-1.5 mu m layer of TiCxNyOz where x+y+z>=1 and z>0, preferably z>0.2 treating said layer at 625-1000 DEG C in a gas mixture containing 0.5-3 vol-% O2, preferably as CO2 + H2 or O2 + H2, for a short period of time about 0.5-4 min, optionally in the presence of 0.5-6 vol-% HCl and depositing said Al2O3-layer by bringing said treated layer into contact with a gas mixture containing 2-10 vol-% of AlCl3, 16-40 vol-% of CO2, in H2 and 0.8-2 vol-% of a sulphur-containing agent, preferably H2S, at a process pressure of 40-300 mbar. The invention also includes a cutting tool insert with a coating including at least one alpha -Al2O3-layer according to the invention. <IMAGE> |
