Oxidation resistance and physical properties of ZrB2-SiC-HfB2 coating reinforced with diboride

In order to effectively improve the density and oxidation resistance of ZrB 2 -SiC coating materials, HfB 2 was added into ZrB 2 -SiC system and their physical properties, oxidation resistance were explored. It was observed that the flexural strength of the spark plasma sintered sample with 8 vol% HfB 2 was 717.1 MPa, which was 162.6 % higher than that of the sample without HfB 2 (273.1 MPa). At the same time, the oxidation activation energy of the sample with 15 vol% HfB 2 was increased to 511.98 kJ/mol, showing excellent oxidation resistance. The oxidation process is that HfB 2 and ZrB 2 were oxidized prior to SiC to form HfO 2 and ZrO 2 to form a dense oxide layer on the outermost layer of the sample, and SiC reacted to form a second dense SiO 2 layer to hinder oxygen intrusion. In summary, diboride can achieve the synergistic effect of improving the oxidation resistance and structural optimization of ZrB 2 -SiC-HfB 2 coatings composites, which provides a theoretical basis for its practical application.