Research on preparation and property of borosilicate glass coating for C/C composites

The effects of the ratio of SiO₂ and B₂O₃, the type of addition with high melting point including MoSi₂, Y₂O₃, SiC on the high temperature stability and fluidity of the borosilicate glass coating were studied. Borosilicate glass coating with good high temperature stability and fluidity was prepared on the surface of SiC coated carbon-carbon (C/C) composites. The isothermal oxidation resistance of SiC/borosilicate glass coated C/C composites was also tested under 1500°C in air. The study results showed that the borosilicate glass exhibits good high temperature stability and fluidity as the ratio of SiO₂ and B₂O₃ was 4: 1. The addition of MoSi₂ can improve the oxidation resistance of borosilicate coating, and the better oxidation resistance borosilicate glass coating can be obtained as the mass ratio of borosilicate glass and MoSi₂ was 4: 1. The mass loss of the SiC/borosilicate glass coated C/C composites was only 4.31% after oxidation for 17 h.