Ablation resistance of ZrO2-encapsulated ZrB2 coating with 3D thermal conduction network applied over carbon/carbon composites

In this work, ZrO2 with different ZrB2 contents (0, 15, 30,40 wt.%) composite powders were synthesized by sol-gel, then they were sprayed on carbon/carbon composites using plasma spraying to construct a three-dimensional (3D) thermal conduction network within the formed coating. Oxyacetylene ablation tests were carried out under 4.2 MW/m2 to investigate the effect of the 3D thermal conduction network on the ablation resistance of coated samples. The encapsulation structure formed during sol-gel process benefits to slowing the oxidation rate of ZrB2 and the content of ZrB2 is critical for establishing a stable 3D thermal conduction network within the coating.