Abstract:
The importance of electrical insulators for various house hold goods and power industries needs the exploitation of geomaterials which are available in Ethiopia. This work deal with the exploitation of talc, kaolin, and bentonite deposits, as a raw material in the manufacturing of electrical voltage resistant material. The chemical compositions of the geomaterials were characterized by XRF. The particle size distribution, mass composition and formulation were selected from a review of the literature. Attempts have been made to study the pressing pressure, sintering temperature, and soaking time effect on the production process and electrical properties of the material developed. The specimens were compacted by dry pressing method at different pressures of 30 MPa, 40 MPa, and 50 MPa. The materials have been dried at 110 ℃ and sintered at different temperatures of 1100, 1200, and 1300 ℃ for 1, 1.5, and 2 hrs. soaking time and 10 ℃/minute firing rate. The optimization of process parameters for the ceramic insulator was investigated using GFD. The specimens were characterized in terms of bulk density (0.987-2.901 g/cm3), apparent porosity (1.567-19.871 %), water absorption (0.891-9.982 %), shrinkage (4.562-8.643 %), compressive strength (6-30MPa), and dielectric strength (6.3-11kv/mm). The micro structural investigation was carried out by both XRD and SEM. The experimental results showed that at 1288.34 ℃ sintering temperature, at 41.47MPa pressing pressure and 1.97 hr soaking time are found to be the best for electrical voltage resistant ceramic material production. In conclusion the results of this study confirmed that the local geominerals have properties that can be potentially used to the manufacturing of electrical voltage resistant ceramic materials.
