High pressure and high temperature production of diamonds
US7241434B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 8, 2001 |
| Grant date | Jul 10, 2007 |
| Priority date | — |
| Expiry date | Sep 28, 2022 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01J2203/0695
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
The present invention is directed to a method for treating discolored natural diamond, especially Type IIa diamond and Type IaA/B diamond with nitrogen as predominantly B centers, for improving its color. The method includes preblocking and preshaping a discolored natural diamond to prevent its breakage in a high pressure/high temperature (HP/HT) press, placing said discolored natural diamond in a pressure transmitting medium which is consolidated into a pill. Next, the pill is placed into a HP/HT press at elevated pressure and elevated temperature within the graphite-stable or diamond-stable range of the carbon phase diagram for a time sufficient to improve the color of said diamond. Finally, the diamond is recovered from said press. Colorless and fancy colored diamonds can be made by this method.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.