The Role of Sintering Additives on Synthesis of High Performance Ceramic- Matrix Composites (Cmcs) by Volume Combustion in The Tio2–Al–C System: Structural and Mechanical Properties

Abstract

The purpose of this work is to decrease or eliminate porosities in ETE-VC products with sintering additives. The Ti–C system has been synthesized for its advantages for refractory, abrasive and structural applications. We attempted to density TiC by using iron addition; this metal is introduced through a secondary reaction 3TiO3 +Al. This mixture reacts exothermically ϪH298= -1072.7 kJ and the heat is released according to by Fe addition 3TiO3 +4Al+3C+xFe→3TiC+2Al2 O3 +xFe. X-ray diffraction analysis indicated that intermetallic Fe3 Al, TiC and Al2 O3 are the main phases formed in the reinforced high performance ceramic-matrix composites and the additions of Fe decreased the lattice parameter of TiC. Field emission scanning electron microscopy examinations showed that the addition of Fe decreased TiC particle size and changed their growth controlling mechanism. Also, Raman spectroscopy analysis showed that at higher Fe contents, oxygen dissolved in the TiC crystal structure leading to the formation of titanium oxy-carbide with lower lattice parameter and residual un-reacted carbon in the products. The adiabatic temperatures for the reactions containing % Fe estimated using the thermodynamic data. Thus, doping method is finally used to fabricate materials by ETE-VC method (volume combustion method) for industriel applications.