Preparation and Characterization of Glass Matrix Composite with Coal Fly-ash Waste

Abstract

Glass matrix composites have been fabricated from waste materials by employing powder technology route. Flyash waste from thermal power plant and commercially available borosilicate glass powders were used in the present investigation. These precursor materials were mixed in the content of 25, 50, 75 and 90 vol% flyash, milled, compacted and sintered at the low temperatures, i.e. 800, 900 and 10000C for 2 and 4 hours annealing times respectively. For flyash content up to 25% by volume, a moderately high relative density compact (of about 92%) could be fabricated by using low sintering temperature (800oC/4 hrs). The higher as-received flyash content jeopardized the viscous flow densification that resulted in reduction of relative density with increase in flyash content. The relative density also increased with processing temperature for almost all compositions. The addition of micron-sized alumina particles as a reinforcement resulted in augmentation of densification and mechanical properties of the compacts. A two-fold increment of diametral compressive strength was achieved in the case of flyash-borosilicate glass compact processed with 10 vol% of alumina. These results indicate that by using a simple, cost-effective powder technology method and relatively low sintering temperature, sufficiently dense flyash containing materials were produced which may compete with conventional glass-ceramics in technical applications.