Oxidation resistance of Zr- and Hf-diboride composites containing SiC in air plasma up to 2600 K for aerospace applications

Microstructure-controlled and fully-dense ZrB2 HfB2 composites were elaborated by Spark Plasma Sintering with two different amounts of SiC (20 30 vol%) added to improve their oxidation resistance using optimized sintering parameters. Oxidation several samples in air plasma conditions, at 1000 Pa total pressure from 1800 K up 2600 K, was carried out. The mass variation during duration 300 s on a temperature plateau followed. A four-step mechanism, identified four singular behaviors depending the ranges, proposed detailed. normal emissivity measured pre-oxidized high values around 0.90 obtained 1300 1900 due presence oxide layer formed conditions this is interesting for aerospace applications.