| 摘要 |
Diamond and diamond-like powders are produced by laser-induced pyrolysis in a throughflow reactor consisting of a laser (1) and an associated beam guide system; a partially transparent mirror (2); a reaction chamber (4) equipped with windows (13) which are transparent to the laser wavelength employed, beam energy measuring equipment (3), gas lines (14, 15), flowmeters (13), pressure and temperature sensors (12), a furnace (9) and observation windows (7); a separation unit (10) for separating solid, liquid and gaseous products; and a vacuum pump (11). A first process employs a high power CO2 laser (1) with greater than 42 W output power, one or more strong IR absorption bands of at least one of the gaseous reactants overlapping one or more of the laser wavelengths, and a second process employs a high power laser (1) emitting in the IR region above 800 nm. and the UV region below 400 nm., one or more strong UV or IR absorption bands of at least one of the gaseous reactants overlapping one or more of the laser wavelengths. The diamond particles form and grow from precursor molecules in the gas phase; the reaction gas stream and the laser beam are co-linear in the reaction chamber (4); the process is continuous and uses a high power laser system permitting variation of beam density over a very wide range; and non-diamond products are re-converted to gaseous compounds using reducing or oxidising agents, so that separation and purification of the diamond powder from other reaction products is simplified. Also claimed are a reactor, as described above, and a plant for carrying out the above processes.
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