Effect of Quebracho Bark on the Properties of Opaque Glazes
In this work, the effect of quebracho bark (QB) on the physical and chemical properties of opaque glaze/glazes (OG) was investigated. Various ratios (0.25-10 weight percent) of quebracho bark were incorporated into the glazes to obtain experimental glaze recipes and melting temperatures of the glaze compositions were calculated through the fluxing factors of the oxides present in the glazes. Thereafter, the glaze compositions were fired at the calculated temperature value of 1100°C. Viscosity, thixotropy and pH tests were conducted on OG and OG+QB glaze suspensions. Standard coloring analyses, crazing resistance, impact resistance, resistance to acid and alkalis, water absorption, firing strength, and surface hardness tests were conducted. After establishing the Seger formulas, surface tensions of the glazes were calculated by making use of the molar surface tension factors of the oxides already present in the glaze compositions at the same sintering temperature of 1100°C. QB additions decreased the viscosity and standard thixotropy values of the OG and had no significant effect on the pH of the OG slurry. On the other hand, QB additions caused an increase in the whiteness (opacity) of the OG. No crazing and impact fractures were observed on the glaze surfaces. Furthermore, the glaze surfaces showed good resistance to acid and alkalis. On QB incorporation, water absorption decreased in all the experimental glazes. Firing strength and surface hardness increased with increasing QB content. According to the experimental results, 5 weight percent (wt. %) QB addition was found to be the optimum amount.
Keywords:
Opaque glaze, quebracho viscosity, thixotropy, physical properties,
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- 1. Lakeside Pottery, Glazing - Mixing, Using, Application, Glazes – Overview. http://www.lakesidepottery.com/HTML%20Text/Tips/Mixing%20and%20Using%20Glazes.htm, 2018, (accessed 08.06.2018).
- 2. Singer, F. and Singer, S., Industrial Ceramics; Chapman and Hall: London, UK, 1984, 1455 pp.
- 3. İsrail, L İ., Köseoğlu, K., Cengizler, H., Effect of silver oxide on colour variation and gloss of opaque glazes, Transactions of the Indian Ceramic Society, 2014, 73, 22-30.
- 4. Pekkan, K., Karasu, B., Production of opaque frits with low zro2 and zno contents and their industrial uses for fast single-fired wall tile glazes, Journal of Materials Science, 2009, 44, 2533-2540. 5. Parmelee, C. W., Harman, C. G., Ceramic glazes, 3 rd Edition, Cahners Books: Boston, USA, 1973, 612 pp.
- 6. Romero, C., Bark Ecology, Ecology, INFO 34. http:// www.ecology.info/bark-ecology.htm, 2012, (accessed 08.06.2018). 7. Bechtold, T., Mahmud Ali, A., Mussak, R. A. M., Reuse of ash tree bark as natural dyes for textile dyeing: process conditions and process stability, COTE, 2007, 123, 271-279.
- 8. Mckay, G., Porter, J. F., Prasad, G. R., The removal of dye colours from aqueous solutions by adsorption on low-cost materials, Water, Air, and Soil Pollution, 1999, 114, 223-229. 9. International standard DIN 53211Din4 Flow Cup.
- 10. TS EN ISO 10545-16, Ceramic tiles - Part 16: Determination of small colour differences, Turkey, June 2012.
- 11. Hunter, R. S., Harold, R. W., The Measurement of Appearance, 2nd edition. John Wiley and Sons Inc.: New York, USA, 1987. 12. HunterLab, “Hunter L, a, b Color Scale”, Insight on Color, vol. 8, no. 9, downloaded from http://www.hunterlab.com/appnotes/an08_96a.pdf, 2008, (accessed 08.06.2018).
- 13. TS EN ISO 10545-5, Ceramic tiles Part 2, Determination of dimensions and surface quality, Turkey, April 2000.
- 14. TS EN ISO 10545-11, Ceramic tiles – Part 11, Determination of crazing resistance for glazed tiles, Turkey, December 1997.
- 15. TS EN ISO 10545-13, Ceramic tiles Part 13, Determination of chemical resistance, Turkey, April 2000.
- 16. TS EN ISO 10545-3, Ceramic Tile Part 2, Determination of water Absorption, apparent porosity, apparent relative density and bulk density, Turkey, April 2000.
- 17. TS EN ISO 10545-4, Ceramic Tile Part 4, Determination of modulus of rupture and breaking strength, Turkey, April 2000.
- 18. TS EN 101, Ceramic Tiles- Determination of scratch hardness of surface according to mohs, Turkey, April 1995.
- 19. Digtalfire.com, Reference library. https://digitalfire.com/4sight/glossary/glossary_viscosity.html, 2015, (accessed 08.06.2018).
- 20. Spectrum glazes, Adjusting Glaze Viscosity and Density. http://www.spectrumglazes.com/viscpg.html, 2018, (accessed 08.06.2018).
- ISSN: 1305-130X
- Başlangıç: 2005
- Yayıncı: Manisa Celal Bayar Üniversitesi Fen Bilimleri Enstitüsü