Additively-manufactured multiphase coatings with laser protection ability for the repairing of MoSi₂-SiC/SiC coated C/C composites

The Si-SiC-MoSi₂ and Si-SiC coatings were proposed to repair the damaged MoSi₂-SiC/SiC coated C/C composites by laser directed energy deposition. Laser ablation was used to assess the repair effect. Results showed that both the repaired coatings with dense structure could restore the geometric size of damaged area. Compared with the Si-SiC-MoSi₂ coating, the Si-SiC repaired coating with higher laser reflectivity and more free Si could reduce the heat generation and enhance the heat dissipation during ablation, which lowered the maximum temperature by 347.49 K and 810.77 K under 300 W and 500 W ablation for 7 s separately, beneficial to avoid the secondary laser damage of the repaired area.