Reactive synthesis of ceramic matrix composites under pressure

Near fully dense in situ ceramic matrix composites were fabricated from ble nds of fine Ti-B4C, Ti-BN, Ti-SiC, Ti-B6Si and Al-TiO2 powders without or w ith the addition of Ni. Two reactive synthesis techniques were employed: th ermal explosion/TE (SHS) under pressure and reactive hot pressing/RHP. In b oth approaches, the processing or preheating temperature (less than or equa l to 1100 degrees C) was considerably lower than those typical of current m ethods used for processing of ceramic matrix composites. Partial to full co nversion of reagents into products was achieved during TE, and a moderate e xternal pressure of 150 MPa was sufficient to ensure full density of the fi nal products. RHP processing yielded dense materials with finer microstruct ures, however full conversion of reagents into products was not achieved. ( C) 2000 Elsevier Science Ltd and Techna S.r.l. All rights reserved.