Ceramic engineering strengthens body armour for soldiers

University of Melbourne chemical engineering researchers are part of the award-winning team that has developed new lightweight body armour being used to protect Australian soldiers in armed conflicts.

The new armour is made of boron carbide ceramic. It is tough enough to stop an armour-piercing bullet, but up to 20 per cent lighter than previous armour. For a single breastplate, this could reduce the weight a soldier carries by 600 grams, providing better protection while improving their mobility and endurance.

Professor George Franks, who led the University of Melbourne team involved in the collaboration, says the strength of boron carbide has long been recognised. When CSIRO developed a new process to form the ceramic into curved shapes — such as breastplates — the University of Melbourne helped to refine the boron carbide formula to ensure the ceramic would retain its strength in the new curved forms.

The ceramic is created from boron carbide powder that is mixed with water and other ingredients to the consistency of modelling clay. This is then pressed into the desired shape. However, ceramics are brittle and any flaw, such as an air pocket or crack, reduces the strength of the material, Professor Franks says.

“The fundamental science in this work is understanding how to control the plasticity of the ceramic compound when liquid is added. What chemical properties will help to control the flow of the material when it is shaped, so that we can preserve the qualities we need?”

In the case of body amour, a high-strength and lightweight combination is required. Other applications in industries such as refining or aerospace might require greater corrosion or heat resistance.

The boron carbide ceramic research was part of a Defence Materials Technology Centre project. Other partners included CSIRO, Swinburne University of Technology, the Victorian Centre for Advanced Materials Manufacturing and Australian Defence Apparel, which manufactures the armour vests.

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Professor George Franks