Vapor-grown carbon manufacture using hot isostatic pressing under very high gas pressures

Isostatic pressing technologies have been used since the 1950s to produce high-strength, dense, and homogeneous materials for metals, ceramics, and carbon. Depending on the processing temperature, these technologies are classified as cold, warm, and hot isostatic pressing (HIP). Conventional applications have focused on physical processes such as forming, sintering, densification, and diffusion bonding, enabling the manufacture of refractory metals, consumable electrodes, cemented carbides, and isotropic graphite. A unique HIP-based method has been developed for the vapor-phase growth of carbon materials through chemical reactions under high gas pressure. Materials such as flower-like graphene, seed-like graphene, graphene grown on carbon-fiber surfaces, and large-diameter, thin-wall carbon were synthesized that have unique properties compared with products grown by conventional chemical vapor deposition under reduced pressure. The HIP process also offers high productivity because large industrial HIP systems can process substantial quantities of raw materials in a single batch. This review presents applications of vapor-phase-grown graphene, including electrodes and neutron reflectors.