Characterization and Properties of Powder Metallurgy Alumina-Copper Ceramic Composites

The demand for a material that has special properties of high hardness, wear and fatigue resistance and high thermal conductivity is increasing in the recent days. This dissertation focused on how to produce a composite material with these desired characteristics. A composite is a material that consists of at least two materials with chemically and physi-cally distinct phases suitably distributed to produce properties that are not obtainable with either of the individual phases. The ceramic matrix and reinforcement used in this inves-tigation were alumina and copper, respectively. Three compositions of the composites that were studied: 75% Alumina and 25%copper, 80% Alumina and 20%copper, 85% Alu-mina and 15%copper. The main objectives of this study was to fabricate the composite that produce highest hardness by using different amount of copper. The composite sam-ples were produced through powder metallurgy techniques. The powder was first mixed to a uniform homogeneous layer and green samples were then produced by compaction. The green samples were sintered in the argon atmosphere furnace. Scanning Electron Mi-croscope (SEM) has been conducted to show the dispersion of copper with alumina and the microstructures were analyzed. By changing mass percentage of copper with alumina, different microstructures were observed. The highest hardness of the evaluated compo-sites was found in the 75% Alumina and 25%copper which was 80.6HV. As the composite was heated or sintered up to a temperature of 1500°C, the copper particles melts and the bonding decreases due to the high temperature. Based on this investigation the highest hardness i.e. 80.6 HV was found in the 75% Alumina and 25% copper composite.