Near‐Net‐Shaping Methods for Ceramic Elements of (Body) Armor Systems

Abstract

Shape‐forming techniques which may be useful in producing components for body armor are reviewed. The techniques are classified in three general categories, dry, wet, and plastic. The different shaping techniques are compared based on key parameters including shape limitations, rate of production, cost, and safety. The techniques are evaluated as to their suitability to be used to produce different body armor components such as breast plates, deltoid, shin and knee protection, and helmets. Dry‐pressing is the current standard for producing “relatively flat” components such as breast plates, but performance is limited by the inherent problem associated with dry‐pressing, namely, the difficulty in producing homogeneous green bodies because of agglomerates in the powder. Plastic processing has the potential to be useful to produce more reliable “flat” components with improved performance due to high shear mixing breaking up agglomerates. Wet (colloidal) processing techniques such as gelcasting and freeze casting may be useful to produce components with high curvature and more complex shape such as helmets. Tiles or segments may be combined to produce shaped components with increased flexibility.

Porous YbB6 Ceramics Prepared by In Situ Reaction between Yb2O3 and B4C Combined with Partial Sintering

“…When the pressure is applied, these powders would exhibit strong pressure sensitive packing because they have attractive interactions due to van der Waals attraction . The decreased particle interspaces resulted from the increased pressure causing the green body to be more compact, which leads to less shrinkage during sintering and introduces porosity in the final product . As a result, the final density increases with the increase in green density, but the porosity and volume shrinkage decrease.…”

“…27 The decreased particle interspaces resulted from the increased pressure causing the green body to be more compact, which leads to less shrinkage during sintering and introduces porosity in the final product. 28 As a result, the final density increases with the increase in green density, but the porosity and volume shrinkage decrease. Figure 5 exhibits the representative microstructures of fracture surface of porous YbB 6 ceramic derived from green density of 1.93 g/cm 3 .…”

Effect of polydimethylsiloxane on the mid-temperature strength of gelcast Al2O3 ceramic parts

“…Gelcasting is a well-established colloidal forming technique to enable near-net shaping of complex ceramic parts with varying cross-sections, with a short forming time, high yields and low-cost machining [1,2]. However, being restricted to the mold opening process, fabrication of ceramic parts with complex internal cores cannot be easily realized by this technique, such as the ceramic mold for hollow turbine blade.…”

Characterisation, significance and detection of manufacturing defects in Reaction Sintered Silicon Carbide armour materials

“…1 shows a typical body armour production facility and associated products. In a recent review, carried out by Leo et al [4], of the shaping techniques used for body armour components, uniaxial pressing of breastplates was still recognised to be the most feasible, and commercially available, process even though other techniques like Viscous Plastic Processing (VPP) were becoming established. One particular variant of the dry-pressing route is known as Reaction Sintering, or Reaction Bonding, in which a prepressed, dry powder compact is infiltrated, at elevated temperature, with a liquid metal.…”