Influence of TiC on Density and Microstructure of Al₂O₃ Ceramics Doped with Nb₂O₅ and LiF

Abstract

Ceramic matrix composites are widely studied in the ballistic sector due to their high hardness, fracture toughness, and improved ballistic performance in multilayer shielding systems. However, the presence of dopants in ceramics can pose challenges during processing and potentially compromise the final properties of the sintered material. This study focused on the ceramic processing of Al₂O₃-based ceramic matrix composites by adding 4 wt.% Nb₂O₅ (niobium oxide), 0.5 wt.% LiF (lithium fluoride), and 38.5 wt.% TiC (titanium carbide). The composites were produced using cold uniaxial pressing and conventional sintering at 1400 °C for 3 h. The composites were characterized using Archimedes’ principle and scanning electron microscopy (SEM). The results revealed that the samples to which TiC was added exhibited low initial densities, indicating that the applied pressure of 50 MPa during cold pressing was insufficient to adequately densify the green bodies. Moreover, the presence of TiC led to a significant reduction in densification, making it challenging to apply a conductive coating for SEM analysis. Adjustments to the intensity of the electron beam were necessary to conduct the analysis successfully. Conversely, the samples to which TiC was not added exhibited high density values in the green state and yielded consistent results after sintering in line with previous research, indicating a satisfactory degree of sintering in the absence of TiC. These findings highlight the importance of carefully considering the addition of TiC in ceramic matrix composites during processing, which can have a significant impact on densification and subsequent material properties. The results contribute to the understanding of processing parameters with regard to the production of ceramic composites with desirable characteristics for ballistic applications.