Armours form a key component of the modern soldier’s protective equipment. Ceramics have higher hardness and lower density than traditional metals, providing a more capable and lighter armour. Armour can however decrease mobility and increase soldier fatigue. Boron carbide (B4C) has a high hardness, with a density lower than other ceramic armours such as silicon carbide (SiC), suggesting it has good potential as an armour material. However, under high impact pressures it is seen to undergo a polytype breakdown resulting in an amorphous phase. This culminates in a loss of mechanical properties. It has been suggested that a composite of B4C and SiC could have an increased amorphisation resistance. To investigate this, microemulsion silica (SiO2) was combined with a carbon source to produce SiC precursor powders. These were used to develop B4C-SiC composites with a range of microstructures. A 3D non-destructive Raman method was developed to investigate the amorphous region generated by indentation hardness experiments.

Microemulsion produced SiO2 was found to have a well controlled particle size distribution with a mean size of 65 nm. The conversion of SiO2 to SiC was found to produce β-SiC from a range of reactions. B4C-SiC composites were then developed, in an 88:10 ratio. Starting powders containing microemulsion SiO2, commercial B4C and a carbon source produced composites with a high relative density of 97.7 % and a homogeneous dispersion of the SiC phase. This was achieved when the SiO2 and carbon source were intimately mixed, before being added to other components. These composites exhibited a higher than expected hardness of 39 GPa. A non-destructive 3D Raman method was developed to probe the amorphous zone under indents. This indicated that it is unlikely that SiC can prevent the amorphous breakdown of B4C when added as a majority or minority phase.