Optimized conditions for cobalt diffusion in Sri Lankan colorless topaz and coloration mechanism elucidation through spectro-chemical investigation
| Autor: | Chandana. P. UDAWATTE, Sunil ABEYWEERA, L. R. K. PERERA, Sandun ILLANGASINGHE, Chirath WEERASOORIYA, Chakkaphan SUTTHIRAT, Naleen JAYASINGHE, Tilak DHARMARATNE, Saranga DIYABALANAGE |
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| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | Journal of Metals, Materials and Minerals. 33:73-81 |
| ISSN: | 2630-0508 0857-6149 |
| Popis: | Most of natural topaz is colorless; thus, methods of color enhancement are widely used for coloring this mineral. Currently, blue color is obtained by cobalt diffusion due to drawbacks in existing coloration methods. In this study, optimum conditions suitable for Cobalt diffusion in Sri Lankan colorless topaz were investigated and coloration mechanism was elucidated. The diffusion agent was prepared by mixing CoCO3 with Na2CO3, CaCO3 and carbon powder and diffusion was carried-out by varying the temperature and soaking time. Chemical analysis, UV-Vis absorption spectrum, infrared absorption spectra, and Raman peaks of diffused and non-diffused topaz were tested. The results clearly indicated that the optimum condition for Co diffusion in Sri Lankan topaz is 950℃ for 11 h. The EPMA analysis showed that the Co concentration in the diffused sample varied from 0.001 wt% to 0.027 wt% while colorless topaz showed |
| Databáze: | OpenAIRE |
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