Enhanced alumina layer produced by CVD
US7396581B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 1, 2006 |
| Grant date | Jul 8, 2008 |
| Priority date | — |
| Expiry date | Sep 1, 2026 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/30
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The present invention introduces a new and refined method to produce α-Al2O3 layers with substantially better wear resistance and toughness than the prior art. The α-Al2O3 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 α-Al2O3 is obtained through a nucleation step being composed of both aluminising and oxidisation steps. The α-Al2O3 layer according to this 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 5 to 9. The layer is characterised by a strong (012) growth texture, measured using XRD, and by the almost total absence (104), (110), (113) and (116) diffraction peaks.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.