Growing diamonds - while suppressing non-diamond carbon growth by alternating pulses of supersaturation and non-diamond disin

• Main Authors: B.V. SPITSYN, V.A. RYABOV, B.V. DERYAGIN, L.L. BUILOV, V.M. ZUBKOV, D.V. FEDOSEEV, A.V. LAVRENTIEV, A.V. BOCHKO
• Format: Patent
• Language: English; French
• Published: 17.08.1972
• Subjects: AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR; CHEMISTRY; CRYSTAL GROWTH; METALLURGY; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; REFINING BY ZONE-MELTING OF MATERIAL; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; SINGLE-CRYSTAL-GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL

In growing diamond on a seed-crystal in a carbonaceous-gas medium, periodically-repeated pulses of super-saturation are created in the gaseous med whose duration is less than that required to form non-diamond carbon nuclei of critical dimensions, the interval between pulses being sufficient for the disintegration of these nuclei. The pulse time is pref. between 10-5 and 10 sec. the interval being >=10-5 sec. using periodic temp. pulses. During a pulse, the surface of the seed-crystal is maintained at 800-3500 degrees C. The gas is methane or octane at than 200 mmHg. The object is to form the meta-stable diamond while preventing the formation of non-diamond carbon.