Ablation resistance of wedge-shaped C/C-ZrB2-ZrC-SiC composites exposed to an oxyacetylene torch

The ablation resistance of wedge-shaped C/C-ZrB2-ZrC-SiC composites was studied under an oxyacetylene torch. Ablation morphologies and phase compositions were examined by SEM and XRD. As exposed to low heat flux of 2.38 MW/m(2), a porous and homogeneous ZrC-ZrO2 skeleton generated. With the increasing of heat flux, ceramic oxides at the tip became loose and fragmented instead of sintering together. Besides that, owing to the wedge-shape of the specimen, high gas pressure mainly concentrated at this region. The high gas pressure and strong shear scouring of flame resulted in the limited accumulation of ceramic oxides. This led to an inferior ablation of wedge-shaped C/C-ZrB2-ZrC-SiC composites in high heat flux of 4.18 MW/m(2). (C) 2016 Elsevier Ltd. All rights reserved.