| 摘要 |
File ref.: P 36 25 743.5 Applicant: Ernst Winter /A Sohn (GmbH /A Co.), Hamburg My file: 6087/86 For the use of diamond grains as a constituent of cutting tools or other tools, the diamond grains are usually held in a bond, especially a metallic bond. In this case, the holding is reinforced if the diamond grains have a roughened surface. This can be accomplished by etching. In the known processes for treating diamond surfaces, however, the result is partial destruction thereof, if the treatment is carried out at high temperatures, i.e. above 1,000.degree.C, or a large loss of diamond material. This is avoided, if the diamond grains (1) are exposed, for enlarging their surface to at least twice their natural surface area by carving out pores, to a stream of hydrogen or a hydrogen-containing gas at a temperature above 700.degree.C, while embedded in a metal powder. The diamond grains (1) can then be purified with an acid. Iron, cobalt, nickel or an alloy of these metals can be used as the metal powder.
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