Aluminum oxynitride having improved optical characteristics and method of manufacture
US4481300A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 13, 1984 |
| Grant date | Nov 6, 1984 |
| Priority date | — |
| Expiry date | Jan 13, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S501/904
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method of preparing substantially homogeneous aluminum oxynitride powder is provided comprising the steps of reacting gamma aluminum oxide with carbon in the presence of nitrogen, and breaking down the resulting powder into particles in a predetermined size range. A method of preparing a durable optically transparent body from this powder is also provided comprising the steps of forming a green body of substantially homogeneous cubic aluminum oxynitride powder and sintering said green body in a nitrogen atmosphere and in the presence of predetermined additives which enhance the sintering process. Preferred additives are boron, in elemental or compound form, and at least one additional element selected from the group of yttrium and lanthanum or compounds thereof. The sintered polycrystalline cubic aluminum oxynitride has a density greater than 99% of theoretical density, an in-line transmission of at least 50% in the 0.3-5 micron range, and a resolving angle of 1 mrad or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.