Oxidation protection of B4C modified HfB2-SiC coating for C/C composites at 1073–1473 K

Abstract

B4C modified HfB2-SiC coating for C/C substrate was designed to expand the application of HfB2-SiC based coating in low-medium temperature environment. The oxidation protection behavior of HfB2-SiC based ceramic coatings with and without B4C at 1073, 1273 and 1473 K was tested and analyzed. The experimental results reveal that the oxidative damage of HfB2-SiC coated C/C reduces by over 20% after introducing B4C, which may be due to the protection of borosilicate glass with more suitable viscosity during oxidation. Meanwhile, B4C can improve the oxidation protection ability of HfB2-SiC coating best at 1473 K. And the introduction of B4C can reduce the mass loss of HfB2-SiC coated C/C sample by 77.6% after oxidation for 58 h at 1473 K. The fluidity of glass film becoming better with temperature-rising, and the fluid borosilicate glass layer makes the coated samples have the best anti-oxidation properties at 1473 K among these three temperatures.