| 摘要 |
1,154,633. Synthetic diamonds. ALLIED CHEMICAL CORP. 2 Sept., 1966 [7 Sept., 1965], No. 39411/66. Heading C1A. Synthetic diamonds having an average diameter not exceeding 0-1 Á, a surface area of 40-400 m<SP>2</SP>/g., and having OH, COOH, and Co groups over at least 10% of the surface area, and no visible external crystal faces, are prepared by oxidizing with HNO 3 at at least 280‹ C. the diamonds obtained by exposing graphite to shock pressures in the region of diamond stability, e.g. as described in Specification 1,077,469. The HNO 3 may be above 50% concentrated, and may be diluted with H 2 50 4 , H 3 P0 4 , K 2 50 4 or mixtures thereof. Pressures from 1 to 280 atm. may be used. The diamond may be treated with HCI, HF, and KOH before, and optionally after, the HNO 3 treatment. The product also has the following properties: (a) I.R. peaks at 5À65 and 16À2 Á and bands at 2À8-3À5 Á and 9À2-9À8 Á; (b) a content of 80-95% C, 0À2-2% H, and 0À1-2À5% N (after drying at 200‹ C. for at least 2 hours); (c) a weight loss of at least 5% on heating in Ar at 850-900‹ C. for 4 hours; (d) less than 0-2% inorganic contaminants and graphite; (e) a preferred average particle size of 7-100Š. |
