Development of UHTCMCs via water based ZrB2 powder slurry infiltration and polymer infiltration and pyrolysis

Cf/ZrB2-SiC ultra-high temperature composites were manufactured via aqueous slurry impregnation coupled with polymer infiltration and pyrolysis, using a allylhydrido polycarbosilane precursor. For the first time we used ultra-high modulus pitch-based carbon fibres for the PIP process, investigating three different architectures, 0/0 degrees, 0/90 degrees, and 2D. Microstructure, mechanical properties and oxidation resistance in air at 1650 degrees C were investigated. As expected, the mechanical properties showed the tendency to decrease with increase of the preforms complexity, due to the higher amount of flaws and residual stresses. For instance, the flexural strength was approaching 500 MPa for 0/0 degrees, 370 MPa for 0/90 degrees and 190 MPa for 2D. The materials showed an optimal resistance to oxidation at 1650 degrees C thanks to formation of a viscous borosilicate glass that guaranteed a self healing functionality.