Low-pressure plasma spraying of ZrB2-SiC coatings on C/C substrate by adding TaSi2

To improve the density and ablation resistance of ZrB2-SiC coatings, TaSi2 modified ZrB2-SiC coatings was prepared on C/C composites by low-pressure plasma spraying. Systematical investigations about microstructures of two kinds of ceramic coatings were performed by XRD, SEM, EDS, TEM and X-ray computed tomography. The presence of Ta element in the ZrB2-SiC-TaSi2 coating is mainly in the form of fine particles with nanoscale, (Zr0.8Ta0.2)B2, visible fine particles and densification areas. The addition of TaSi2 is conducive to reducing the porosity of the coatings and improving their mechanical and ablation resistance properties. •The IPS and low-pressure plasma spraying technology were both introduced to prepare the coating layers.•Systematical investigations about microstructures of ZS and ZST coatings were performed by methods of characterization.•The TaSi2 addition in the ZST coatings prepared by LPPS have different microstructures is firstly found and reported.•The ZrB2-SiC-TaSi2 coatings prepared by IPS and low-pressure plasma spraying have lower porosity and better performance.