RBAO COMPOSITES CONTAINING TIN AND TIN TIC

TiC and TiN were tested as candidate materials for particle reinforcem ent of reaction bonded aluminium oxide (RBAO). As part of the reaction bonding process Al-containing green bodies have to be heated in air i n order to oxidize the Al, therefore the oxidation behaviour of any ad ded particles is of critical importance. Previous studies have shown t hat neither TiC nor TiN is sufficiently oxidation-resistant to withsta nd the heating cycle necessary to completely oxidize the Al in the pro cess. Therefore,two alternative approaches were investigated. First, T iC and TiN were retained in incompletely reacted RBAO, resulting in an Al2O3-TiC/TiN composite with alloy and possibly intermetallic phases. These metal phases were obtained from Al and Ti/Zr which formed when Al reduced TiO2 and, to a lesser extent, ZrO2. Second, the reaction of AlN and TiO2 to form Al2O3 and TiN at temperatures above 1350 degrees C was investigated The resulting material contained Al2O3, ZrO2, TiN at temperatures above 1350 degrees C was investigated. The resulting m aterial contained Al2O3, ZrO2, TiN and a nitrogen-containing aluminium titanate. (C) 1996 Elsevier Science Limited.