Browsing by Author "Moyo, Moses George"

Now showing 1 - 1 of 1

Evaluation of Local Ceramic Materials for High Voltage Insulation Application
(Nelson Mandela African Institution of Science and Technology, 2014) Moyo, Moses George
This study investigated the Tanzanian local ceramic material for their potential as raw materials for production of high voltage insulators based on the mix proportion of raw materials and firing temperatures. The raw materials used were: Pugu kaolin, quartz supplied by the Kilimanjaro Industrial Development Trust (KIDT), and Kilimanjaro feldspar. The study characterised both individual raw materials and the blends produced from these raw materials. A total of six batches were prepared by varying the proportion of raw materials. Cylindrical samples of 10 and 60 mm diameter were produced by slip casting method and fired at the maximum temperature of 1100, 1200 and 1300 ºC. Fired samples were tested for insulation resistance, bending strength, and bulk properties. The X-ray diffraction (XRD) analysis showed that on heating Pugu kaolin produces mullite phase which is very important for mechanical and dielectric properties. Furthermore, the highest trend in insulation resistance and bending strength is revealed to samples fired at 1200 ºC with lower values for those fired at 1100 and 1300 ºC. The optimum mix proportion and firing temperature, which compromise both insulation resistance and bending strength is with 33 wt% Pugu kaolin, 11 wt% Kilimanjaro quartz, and 56 wt% Kilimanjaro feldspar at the firing temperature of 1200 ºC. With this mix proportion and firing temperature at maximum insulation resistance of 205800 MΩ at the injection of 1000 V is achieved. The bending strength and water absorption for this mix proportion and firing temperature is 65.358 MPa and 0.01 %, respectively. These results correspond to the standard specifications for ceramic insulators.