The growth of sapphire single crystals

• Main Authors: Golubović Aleksandar, Nikolić Slobodanka, Đurić Stevan, Valčić Andreja
• Format: Article
• Language: English
• Published: Serbian Chemical Society 2001-01-01
• Series: Journal of the Serbian Chemical Society
• Subjects: czochralski technique; sapphire; growth; single crystal; etching
• Online Access: http://www.doiserbia.nb.rs/img/doi/0352-5139/2001/0352-51390106411G.pdf

Sapphire (Al2O3) single crystals were grown by the Czochralski technique both in air and argon atmospheres. The conditions for growing sapphire single crystals were calculated by using a combination of Reynolds and Grash of numbers. Acritical crystal diameter dc = 20 mm and the critical rate of rotation c = 20 rpm were calculated from the hydrodynamics of the melt. The value of the rate of crystal growth was experimentally found to be 3.5 mm/h. According to our previous experiments, it was confirmed that three hours exposures to conc. H3PO4 at 593 K was suitable for chemical polishing. Also, three hours exposure to conc.H3PO4 at 523Kwas found to be a suitable etching solution. The lattice parameters a = 0.47573 nm and c = 1.29893 nm were determined by X-ray powder diffraction. The obtained results are discussed and compared with published data.