Effects of the Sintering Process on Properties of Triaxial Electrical Porcelain from Ugandan Ceramic Minerals

Authors: Peter W. Olupot, Stefan Jonsson, Joseph K. Byaruhanga

Abstract:

Porcelain specimens were fired at 6C/min to 1250C (dwell time 0.5-3h) and cooled at 6C/min to room temperature. Additionally, three different slower firing/cooling cycles were tried. Sintering profile and effects on MOR, crystalline phase content and morphology were investigated using dilatometry, 4-point bending strength, XRD and FEG-SEM respectively. Industrial-sized specimens prepared using the promising cycle were tested basing on the ANSI standards. Increasing dwell time from 1h to 3h at peak temperature of 1250C resulted in neither a significant effect on the quartz and mullite content nor MOR. Reducing the firing/cooling rate to below 6C/min, for peak temperature of 1250C (dwell time of 1h) does not result in improvement of strength of porcelain. The industrial sized specimen exhibited flashover voltages of 20.3kV (dry) and 9.3kV (wet) respectively, transverse strength of 12.5kN and bulk density of 2.27g/cm3, which are satisfactory. There was however dye penetration during porosity test. KeywordsDwell time, Microstructure, Porcelain, Strength.

Keywords: Dwell time, Microstructure, Porcelain, Strength.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1077529

References:

[1] R. C. Buchanan Properties of Ceramic Insulators, in Ceramic Materials for Electronics, 2nd ed. R.C. Buchanan, Ed. New York: Marcel Dekker Inc., 1991, pp. 1-67.
[2] L. Mattyasovszky-zsolnay Mechanical strength of porcelain, J. Am. Ceram. Soc., vol. 40, no. 9, pp. 299-306, 1957.
[3] W.M. Carty and U.Senapati, Porcelain-raw materials, processing, phase evolution and mechanical behavior J. Am. Ceram. Soc. vol. 81, no. 1, pp. 3-20, Jan 1998.
[4] E. J. Schroeder Inexpensive high strength electrical porcelain Am. Ceram. Soc. Bull. 57, pp. 526, 1978.
[5] Y. Kobayashi, O. Ohira, Y. Ohashi and E. Kato, Strength and Weibull distribution of alumina strengthened whiteware bodies Journal of the Ceramic Society of Japan, International Edition 95, pp. 837-841. 1987.
[6] K.S. Das, and K. Dana, Differences in densification behaviour of K- and Na-feldspar-containing porcelain bodies Thermochimica Acta 406,pp. 199-206, 2003.
[7] C.S. Prasad, K.N. Maiti, and R. Venugopal, Effect of rice husk ash in whiteware compositions Ceramics International 27, pp. 629-635, 2001.
[8] S. Maity, and B.K. Sarkar, Development of high-strength whiteware bodies Journal of the European Ceramic Society 16, pp 1083-1088. 1996
[9] K. Dana, S. Das, and K. S. Das Effect of substitution of fly ash for quartz in triaxial kaolin-quartz-feldspar system Journal of the European Ceramic Society 24, pp. 3169-3175, 2004.
[10] C.S. Prasad, K.N. Maiti, and R. Venugopal Effect of silica fume addition on the properties of whiteware compositions Ceramics International 28, pp. 9-15, 2002.
[11] K. Dana, J. Dey, and K. S. Das Synergistic effect of fly ash and blast furnace slag on the mechanical strength of traditional porcelain tiles Journal of the European Ceramic Society 31 pp. 147-152, 2005
[12] C.S. Prasad, K.N. Maiti, and R.Venugopal Effect of substitution of quartz by rice husk ash and silica fume on the properties of whiteware compositions Ceramics International 29, pp. 907-914, 2003.
[13] F.H. Norton, Fine Ceramics, Technology and Applications. New York: McGraw-Hill Book Co. 1970.
[14] O. I. Ece, and Z. Nakagawa, Bending strength of porcelains Ceramics International 28, pp. 131-140, 2002.
[15] S.R. Bragana and C.P. Bergmann A view of whitewares mechanical strength and microstructure Ceramics International 29, pp. 801-806, 2003.
[16] G. Stathis, A. Ekonomakou, C.J. Stournaras, and C. Ftikos, Effect of firing conditions, filler grain size and quartz content on bending strength and physical properties of sanitary ware porcelain Journal of the European Ceramic Society 24 pp. 2357-2366, 2004.
[17] S.P. Chaudhuri, P. Sarkar and A.K. Charkraborty Electrical resistivity of porcelain in relation to constitution Ceramics International 25, pp. 91-99, 1999.
[18] Y. Iqbal, and W.E. Lee Microstructural evolution in triaxial porcelain J. Am. Ceram. Soc. vol. 83, no.12 pp. 3121-3127. Dec. 2000.
[19] W.E. Lee, and Y. Iqbal, Influence of mixing on mullite formation in porcelain Journal of the European Ceramic Society 21, pp. 2583-2587, 2001.
[20] P.W. Olupot, S. Jonsson and J.K Byaruhanga Effects of mixing proportions and firing temperature on properties of electric porcelain from Ugandan minerals Industrial Ceramics, vol. 28, no. 1, pp. 1-10, 2008.
[21] P.W. Olupot, S. Jonsson and J.K Byaruhanga Characterization of feldspar and quartz raw materials in Uganda for manufacture of electrical porcelains J. Aust. Ceram. Soc. vol.42, no.1 pp. 29-35, 2006.
[22] J.B. Kirabira, S. Jonsson and J.K Byaruhanga, Powder characterization of high temperature ceramic raw materials in the Lake Victoria region Silicate Industriels, vol. 70
[9-10], pp. 127-134, 2005.
[23] H. Norsker, and J. Danisch (1993), Glazes: for the self- reliant potter,Braunschweig: Friedr. Vieweg & Sohn Verlagsgesellschaft mbH, 1993.
[24] P.W. Olupot, S. Jonsson and J.K Byaruhanga Development and characterisation of triaxial electrical porcelains from Ugandan ceramic minerals Ceramics International 36, pp. 14551461, 2010.
[25] P.W. Olupot, S. Jonsson and J.K Byaruhanga Study of glazes and their effects on properties of triaxial electrical porcelains from Ugandan minerals Journal of Materials Engineering and Performance, vol. 19(8) pp. 11331142, Nov. 2010.
[26] Analytica AB, Aurorum 10, SE-977 75 Lule, Sweden.
[27] E. Rambaldi, W.M. Carty, A. Tucci and L. Esposito Using waste glass as a partial flux substitution and pyroplastic deformation of a porcelain stoneware tile body Ceramics International 33, pp. 727733, 2007.