A new process for the production of long glassy polymeric carbon hollow ware with uniform wall thickness using a spray technique Original Research Article

Glassy polymeric carbon is produced in the form of open- and closed-end tubes of uniform thickness up to 1 m long. Resol precursor is sprayed automatically to form a thin gelled coating on a rotating heated mandrel. The process is repeated to produce a sheath of thermoset phenolic resin of required thickness. This resin sheath is carbonized and heat-treated between 1270 and 2770 K. Mass loss and contraction are noted. Structure is characterized by X-ray diffraction, which is also used to determine texture. Mechanical properties are measured using a specially designed hydraulic system to relate hoop strain to hoop stress. Hoop strength lies between 20 and 92 MPa, exhibiting brittle fracture variance. The scatter in the hoop strength data masked any heat-treatment temperature effect. The measured electrical resistivity is 7 × 10−2 and 3 × 10−2 Ω-mm for heat-treatments of 1270 and 2770 K, respectively. Local induction heating has been used to demonstrate that the carbonized ware can endure sharp temperature gradients without fracturing. The hollow ware is used as a crucible for a new Bridgman crystal growth technique and for containment of hydrocarbon gases at high temperature.