Boron-modified phenol formaldehyde resin-based self-healing matrix for C_f/SiBOC composites

Abstract

C_f/SiBOC was fabricated from 2D carbon fabric as reinforcement and slurry-containing boron-modified phenol formaldehyde (BPF) resin with silicon as matrix resin using reaction-bonded silicon carbide method. The processing involves synthesis of (BPF) resin by reacting various amount of boric acid with phenol formaldehyde resin, polymer to ceramic transformation at 1450°C under argon atmosphere, with and without silicon, thermal transformation of the polymer matrix composite into a ceramic matrix composite and evaluation of isothermal oxidation for ceramics and its composites at 1000, 1250 and 1500°C. The ceramic studies, confirmed the formation of B₄C, SiC and SiB₄ (SiBOC) mixed phase and the role of boron as a catalyst for graphitisation of free carbon present in the ceramic. Oxidation of C_f/SiBOC composite at various temperatures leads to the formation of borosilicate glass which heals the cracks, hindering the inwards diffusion of oxygen.

Keywords:

• Composites
• Carbides
• Glass ceramics
• Self-healing

Acknowledgements

The authors thank the authorities of VSSC for granting permission to publish this work. One of the authors (Ganesh Babu T) is thankful to Indian Space Research Organization (ISRO) for the research fellowship. Help received from the members of the Analytical and Spectroscopy Division (ASD) for the thermal, chemical and spectral analyses is gratefully acknowledged.