Deposition of large diamond particles in premixed oxyacetylene flame

Diamonds are synthesized in an oxyacetylene flame of a cutting/welding torch under atmospheric conditions. The optimum conditions for producing coarse diamond particles are investigated by varying the distance between the torch nozzle and the substrate from 1 mm to 6 mm. The substrate temperature is controlled by using a water or an air-cooled holder. Single crystalline diamond particles of about 300 microns in diameter and polycrystalline diamond particles of about 500 microns are produced on Si substrates.