Role of BN as a reactant in combustion synthesis of TiB2/Ti2Al(C,N) solid solution composites

摘要

An investigation on formation of the Ti2Al(C,N) solid solution with a broad range of substitutional proportion was performed by solid state combustion in the SHS mode. Metal nitrides, BN and TiN, were adopted as the solid source of nitrogen in the Ti-Al-C combustion system. On account of complete participation of BN in combustion, the BN-added sample is more exothermic than that adopting TiN which imposes a dilution effect on combustion. As a result, the combustion temperature and reaction front velocity are higher for the samples containing BN than TiN. Due to fully-sustainable combustibility, the BN-adopted samples were shown to produce TiB2/Ti2Al(C1-xNx) solid solution composites with x=0.2-0.8 and a TiB2/Ti(2)AIN composite from the sample free of carbon. However, the combustibility range of the TiN-added sample was constrained by lack of sufficient reaction exothermicity. Although the Ti2Al(C,N) solid solution was also produced from the TiN-adopted sample, the degree of substitution in the Ti2Al(C1-yNy) phase was confined to y <= 0.5. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.