Cyclic ablation mechanisms of the YB4-CrSi2 surface-modified Cf/ZrB2-SiC composites at 2600 °C

In this work, YB 4 -CrSi 2 surface-modified C f /ZrB 2 -SiC composites were fabricated by a slurry coating method. The cyclic ablation resistance of the composites was studied at 2600 °C for 300 s using an air plasma test. The ablation mechanisms of the composites were discussed. The Y 3+ can prevent the phase transition of the ZrO 2 and increase the structural stability of the oxide layer. But the oxide layer cannot prevent the inward O penetration resulting from the forming of Zr 0.9 Y 0.1 O 1.95 grains with abundant oxygen vacancy. After the modification of CrSi 2 , the size of Zr 0.9 Y 0.1 O 1.95 grains can be reduced to nano scale. The adequate SiO 2 glassy phase with the uniform distribution of the Zr 0.9 Y 0.1 O 1.95 nano grains can prevent the O penetration effectively and reduce the mass recession rate of the composites.