PENGARUH TEKANAN KOMPAKSI DAN SUHU SINTERING TERHADAP KEKUATAN BENDING DAN KETANGGUHAN RETAK GLASS CERAMICS DARI FLY ASH

Abstract

This research aims to investigate the effect of compacting pressure and sintering temperature on bending strength and fracture toughness of fly ash glass-ceramics. The fly ash is obtained from waste material produced from coal burning thermal power plant in Suralaya. The growing production of fly ash has long caused negative environmental impact, so that one of the solutions to overcome that negative impact is utilizing fly ash to produce glass-ceramics. Specimens were made by mixing 70 wt.% fly ash and 30 wt.% aluminum silicate. Green compacts were produced in the forms rectangular bar (length,     L = 50 mm, width, B = 7 mm, thickness, W = 8 mm) and rectangular bar (length, L = 50 mm, width, B = 7 mm, thickness, W = 8 mm) with a V-notch (SENB). Those green compacts were prepared by using uni-axial pressing with various pressures of 100, 110 and 120 MPa. The green compacts were then sintered at 1050, 1100 and 1150 ^oC with a heating rate of 5 ^oC/ min. The results show that the optimal condition of physical and mechanical properties occurs on specimens with compacting pressure of 120 MPa and sintering temperature of 1100 ^oC, bending strength of 36.98 MPa and fracture toughness of 1.06 MPa.m^0,5. The increase of fracture toughness occurs with the mechanism of crack deflection.