METHOD OF CARRING OUT VOLUMINOUS TRANSFORMATION OF POLYCRYSTALLINE CERAMIC BODY INTO A MONOCRYSTAL, ESPECIALLY OF POLYCRYSTALLINE ALUMINIUM OXIDE INTO SAPPHIRE AND ARTIFICIAL SAPPHIRE OBTAINED THEREBY

• Main Authors: MAXWELL RANDOLPH E, LEVINSON LIONEL M, KALISZEWSKI MARY S, SCOTT CURTIS E, ERIKSON CARL E, JONES MARSHALL G
• Format: Patent
• Language: English; Polish
• Published: 31.07.1998
• Edition: 6
• Subjects: AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR; CHEMISTRY; CRYSTAL GROWTH; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; 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; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ARTCOLLECTIONS [XRACs] AND DIGESTS; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL

Polycrystalline alumina bodies have been converted to sapphire by a solid state conversion process in which a localized energy source is used to heat only a portion of the body to a temperature above 1800 DEG C. Using a laser as the energy source resulted in conversion to sapphire in less than an hour. The polycrystalline alumina bodies had a magnesia content below 50 wppm, an average grain size below 100 microns, and a density greater than 3.97 g/cc.