Production and Characterisation of Porcelain Insulator Modified with Talc and Bentonite
Authors: Mgbemere HE, Obidiegwu EO, Oginni AA
Talc and bentonite were used in this research to modify the properties of porcelain insulators. Ball clay, kaolin, feldspar, quartz, talc and bentonite were weighed, milled and slip cast to produce the samples. Sintering was carried out at 1100 oC for 2 h in an electric furnace. The samples were characterized using X-ray fluorescence, X-ray diffraction, scanning electron microscopy, Mechanical, physical and electrical properties tests. The chemical analysis showed that SiO2 was the major constituent in both the raw materials and porcelain. Linear shrinkage in the samples ranged from 5.5 to 8%, and bulk density from 1.8 g/cm3 to 2.3 g/cm3. Albite and quartz were the main phases in the XRD patterns while the morphology of the samples revealed relatively dense microstructures containing two distinct phases. The compressive stress-strain graph results showed that the modulus values range from 314 MPa for samples without talc to 566 MPa for the sample with the highest talc content. The electrical tests show that the breakdown voltage ranged from 100 to 150 kV while the leakage current values varied from 1.5 mA to 5 mA. The results indicate that while talc addition helped to increase the compressive modulus values and breakdown voltage, the leakage current values also increased. It can be inferred that while talc addition helped to lower the sintering temperature of porcelain, it also helped to slightly increase the leakage current characteristics of porcelain.
Affiliations: Department of Metallurgical and Materials Engineering, University of Lagos, Lagos, Nigeria.
Keywords: Porcelain, Slip Casting, Insulators, Talc, Properties
Published date: 2020/12/30