Annealing type Ib or mixed type Ib-Ia natural diamond crystal
US4124690A · kind A · utility
29Cited by
6References
3Claims
0Family size
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Key dates
| Filing date | Dec 2, 1977 |
| Grant date | Nov 7, 1978 |
| Priority date | — |
| Expiry date | Dec 2, 1997 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01J2203/0695
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Type Ib or mixed type Ib-Ia natural diamond crystal is annealed at an annealing temperature ranging from about 1500.degree. C to about 2200.degree. C under a pressure which prevents significant graphitization of the diamond during the annealing to convert at least 20% of the total amount of type Ib nitrogen present in the crystal to type Ia nitrogen.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.