Sol-gel assisted synthesis of TiB2-B4C composite powder

Composite powders containing titanium diboride and boron carbide have been prepared by sol-gel method at 1450°C using titanium isopropoxide (titanium precursor), boric acid (Boron precursor), sucrose (carbon source), and acetic acid (AcOH) as a solvent. The effect of boron source (trimethyl borate and boric acid) and B₂O₃/TiO₂, C/B₂O₃ mole ratios of starting materials on the final phases has been studied. The progress of reactions was determined using thermal analysis (TGA-DTA). The resultant powders were characterized by X-ray diffraction (XRD) analysis and field-emission scanning electron microscope (FESEM). XRD patterns confirmed the formation of TiB₂, B₄C, and TiC phases after heat treatment at 1450°C at mole ratio of B₂O₃/TiO₂ = 4.5, C/B₂O₃ = 2.4. With increasing the content of boron oxide, the unwanted phases such as TiC and C were reduced. TiB₂ and B₄C composite powders (~5 µm diameter) containing residual carbon (<4 wt%) were synthesized using the mole ratio of B₂O₃/TiO₂ = 10 and C/B₂O₃ = 1.9 at low temperature of 1450°C.