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The effect of kaolin and silica variation on the properties of porcelain insulators


H.E. Mgbemere
I.P. Onyeayana
A.B. Okoubulu

Abstract

Clay, Al2O3, feldspar and silica have been used to produce shackle-type porcelain insulators using slip casting method. The amounts of silica and kaolin were varied from 10 to 30 wt. % while keeping the amounts of other constituents constant. The samples were bisque fired at 900 °C, sintered at 1200 °C for 1 hour glazed using borax fritz. The results showed that as the amount of kaolin decreased, apparent porosity and water absorption increased from 9-19 % and 7-12 % respectively. The bulk density and linear shrinkage decreased from 1.94-1.12 g/cm3 and from 12.5 % - 7 % respectively. Breakdown voltages ranging from 23 kV to 35 kV were obtained while the highest insulation resistance value of 50GΩ was for the sample with 55 % clay, 15 % silica and 25 % feldspar and 5 % Al2O3. The results indicate that moderate variations in kaolin and silica content can be used to produce porcelain insulators for commercial applications.

Keywords: Electrical porcelain, Shackle insulator, Kaolin, Feldspar, Processing.


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eISSN: 2467-8821
print ISSN: 0331-8443