Influence of solvothermal time on oxidation resistance of carbon/carbon composites modified by borate sol

Abstract

Carbon/carbon (C/C) composites were modified with a borate sol-gel precursor by a novel process integrating sol-gel and solvothermal processes in order to improve the low temperature antioxidation properties of the C/C composites. Results show that the surface of the modified composites is covered by a molten B 2 O 3 layer, and the oxidation resistance of the composites is improved with the extension of solvothermal time increasing from 12 to 48 h. After oxidation at 600uC for 6 h, the oxidation rates of the modified C/C composites are gradually decreased. The mass loss of the modified C/C composites at 600uC is due to the diffusion of oxygen along the molten B 2 O 3 layer and the vaporisation of a small amount of B 2 O 3 .

Exploring the Effect of the Solvothermal Time on the Structural Properties and Catalytic Activity of Cu-ZnO-ZrO2 Catalysts Synthesized by the Solvothermal Method for CO2 Hydrogenation to Methanol

“…It is well known that the solvothermal time greatly affects the properties of materials synthesized by the solvothermal method [18,19,45]. During solvothermal synthesis, the reaction time determines the growth rate of the catalyst particles and the interaction between different components.…”

Antioxidant modification of C/C composites by in situ hydrothermally synthesized 4ZnO·B2O3·H2O

“…Unfortunately, they cannot provide effective oxidant protection at low temperatures (400 -800 ° C). B 2 O 3 [13] and B 4 C [14] displayed oxidation resistance for C/C composites well under 1000 ° C, but the organic chemical tributyl borate found in raw materials is not environmentally friendly. In order to solve this problem, zinc borates, which are known to be environmentally friendly fire retardants and smoke suppressants for polymers, rubbers and coatings [15 -18] , were used in the antioxidant modification of C/C composites at low temperature.…”