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Sapphire single crystals
Large single crystals of Ruby (and other crystals such as Sapphire, Garnets, etc...) grown by the Horizontal Directed Crystallization Method (dimensions 250 x 150 x 20-30 mm).
Features:
high melting point, extremely hard and resistant to abrasion, low dielectric constant - excellent electroinsulating properties, low friction coefficient, shock resistant, high refractive index, broad optical transparency (from UV to IR), chemically inert and stable
Applications:
laser, jewelery, optics, optoelectronics, microelectronics, semiconductors, chemical industry, substrates, rods, ribbons, components of machinery and equipment, such as water and electrical meters, relays and watches and other applications
Basic properties:
| Physical properties: | |
| Chemical formula | Al2O3 : Cr3+ |
| Symmetry | ¯3m, R3c |
| a = 4.748 Å | |
| c = 12.957 Å | |
| Specific mass | 3 984 kg.m-3 - 4 010 kg.m-3 |
| Thermal properties: | |
| Melting point | 2 323° K |
| Thermal expansion | 5.0 x 10-6 K-1 |
| Maximum temperature of application | 2 125 - 2 225 K |
| Mechanical properties: | |
| Mohs hardness | 9 - 9.4 |
| Tensile strength | 415 MPa |
| Compression strength | 2 000 MPa |
| Bending strength | 700 MPa |
| Optical properties: | |
| Refractive index | 1.765 at 0.65 µm |
| Transmission | 0.17 - 6.5 µm |
| Chemical properties: | |
| Solubility | insoluble in common bases and acids under 1000° C |
| (is attacked only by HF and H3P04 at above 300° C) | |
| Chemical stability | stable in contact with W, Mo, SiC |
| (in O2 absence) up to melting point | |
