Title: Processing and characterisation of new nanocrystalline Al₂O₃–fly ash composites

Authors: N. Saheb, T.C. Yoong

Addresses: Department of Manufacturing and Materials Engineering, International Islamic University Malaysia, 53100, Kuala Lumpur, Malaysia. ' Department of Materials Science and Engineering, Malaysia University of Science and Technology, 47301, Petaling Jaya, Selangor Darul Ehsan, Malaysia

Abstract: In this study, new nanocrystalline Al₂O₃–fly ash Ceramic Matrix Composites (CMCs) were developed through the powder metallurgy route. It was found that wet milling of the mixture for 18 h improved mixing, decreased the Al₂O₃ crystallite size to around 10 nm, and reduced the fly ash particle size. For samples sintered at 1350°C for 16 h, the addition of 5 wt% fly ash to alumina increased the micohardness from 525 to 1325 HV while the addition of 10 and 20 wt% decreased it to 508 and 444 HV respectively. Composites containing 5 and 10 wt% fly ash had higher density than Al₂O₃, while samples containing 20 wt% fly ash had lower density. Increasing the sintering time led to the increase in the density of all the samples sintered at 1350°C.

Keywords: nanocrystalline aluminium oxide; fly ash; compaction; sintering; ceramic matrix composites; CMCs; powder metallurgy; structural materials; micohardness.

DOI: 10.1504/IJMMP.2008.022623

International Journal of Microstructure and Materials Properties, 2008 Vol.3 No.6, pp.801 - 809

Published online: 19 Jan 2009 *

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