Fabrication and characterization of alumina-based composites by in-situ combustion synthesis in Al-FeTiO3-B2O3-C alumino-thermic system.

In this study, thermal analysis, composition phase, microstructure and physical and mechanical properties of Al2O3-based composites with titanium diboride and carbide reinforcements fabricated by in-situ spark plasma sintering method in Al-FeTiO3-B2O3-C alumino-thermic system have been investigated. This research explores the potential of utilizing Kahnuj (Iran-Kerman) ilmenite concentrate as a replacement for TiO2. The results of the thermal analysis demonstrate that aluminothermic reactions significantly intensify after the melting of aluminum and different compounds of iron aluminides (FeAl, Fe2Al5, and Fe3Al) and titanium diboride (TiB2) and carbide (TiC) are formed. Among the different systems of raw materials (Al-FeTiO3-C, Al-FeTiO3-B2O3, and Al + FeTiO3 + C + B2O3) only for system Al + FeTiO3 + B2O3, the intermetallic compounds of Fe3Al and Fe4Al13 are stable. For heat treatment with higher heating rates, the boron oxide participates more effectively in the aluminothermic reaction and the composition of titanium diboride is more noticeably formed. In the condition of 45 MPa in mechanical pressure, argon gas atmosphere with 3 bar pressure, heating rate of 100 °C/min, temperature of 1400 °C with dwelling time of 4 min (Optimum condition) for in-situ SPS processing of Al-FeTiO3-C system, the composite samples with the highest homogeneity in microstructure, density (4.10 g/cm3), hardness (281HV), bending strength (271.5 MPa) and highest wear resistance (Friction coefficient of 0.3 and 0.003 g of weight loss with 500 m of sliding distance) with optimal phase composition (Fe, Al2O3, TiC,...) was obtained. [ABSTRACT FROM AUTHOR]