| 摘要 |
The present invention introduces a new and refined method to produce ±-Al 2 O 3 layers in a temperature range of 750-1000°C with a controlled growth texture and substantially enhanced wear resistance and toughness than the prior art. The ±-Al 2 O 3 layer of the present invention is formed on a bonding layer of (Ti,Al)(C,O,N) with increasing aluminium content towards the outer surface. Nucleation of ±-Al 2 O 3 is obtained through a nucleation step being composed of short pulses and purges consisting of Ti/Al-containing pulses and oxidising pulses. The ±-Al 2 O 3 layer according to the present invention has a thickness ranging from 1 to 20 µm and is composed of columnar grains. The length/width ratio of the alumina grains is from 2 to 12, preferably 4 to 8. The layer is characterised by a strong (104) growth texture, measured using XRD, and by low intensity of (012), (110), (113), (024) and (116) diffraction peaks. |
