Fabrication and Characterization of Lightweight Ceramic/Polyurethane Composites

: The paper presents the experimental results of fabrication and characterization of ceramic/ polyurethane composites. The composites were fabricated from preforms with gradient of porosity and different pores size. The composites obtained via infiltration of porous Al2O3 ceramics by urea-urethane elastomers poses a microstructure of percolated phases. In order to improve thermal resistance and mechanical properties of composites, fire retardants and silane coupling agent were used. The microstructure of ceramic/ elastomer composites was characterized using X-ray tomography as well as Scanning Electron Microscopy (SEM). The microscopic observations proved that the matrix pores are filled with the elastomer. It was found that residual porosity of composites was up to 5vol. %. Such composites exhibit high initial strength with the ability to sustain large deformations due to combining the ceramic stiffness and rubbery elasticity of elastomer. Static compression tests for the obtained composites were carried out and the energy absorbed during compression was calculated as the area under the stress-strain curve. The dynamic behavior of the composite was investigated using the split Hopkinson pressure bar technique in conjunction with high-speed photography. It was found that ceramic-elastomer composites effectively absorb the energy. Moreover, ballistic test was carried out using armor piercing bullets.