Carbide derived carbon obtained from SiC-based fibers by phosphating-NaOH bath process

Abstract

Abstract Carbide derived carbon (CDC) are unique materials with tunable micro and mesopore size distribution. They are produced selectively removing metallic elements from carbides. Halogenation or hydrothermal treatments were, therefore, extensively studied. The study reports a new route to produce such carbon, aforementioned CDCp, applied to SiC-based fibers by reacting phosphoric acid vapors at 580–800\u202f°C range, followed by condensed silicophosphate dissolution in tempered NaOH bath. Fibers could be, this way, fully or partially transformed. Obtained CDCp show a broad pore size distribution extending from microporosity (7–9\u202fA) to mesoporosity (up to 60\u202fA), specific surface area >1000\u202fm2\u202fg−1 and pore volume >0.7\u202fcm3\u202fg−1. Mesoporosity may infer from partial carbon oxidation or in-situ silicophosphate and carbon demixion at nanoscale. CDCp burn-off kinetics and tensile strength of non-etched fiber core are discussed. Depending on phosphating conditions, monolayer or concentric CDCp tubes could coat each individual fiber within complex fabric geometry.