Organomorphic composites are obtained by pyrolysis of heat‐treated molded polymer fibers followed by compacting the resulting Ipresskon® preform using carbon or silicon carbide. The structure of these materials features the most uniform volume distribution of a fiber and a matrix. The carbon–carbon (C/C) composite bushings made in this way show a very high compressive strength (up to 390 MPa) and a radial tensile strength (150 MPa). These characteristics ensure high performance of hot pressing molds for ceramics conventionally made of isostatic graphite characterized by much lesser tensile strength. This paper describes the microstructure and properties of C/C‐Ipresskon® composite that was used instead of graphite as a hot pressing mold die. The material structure was found to show a slight transformation after 22 cycles of high‐temperature thermal/mechanical loading at a temperature up to 2000°C and 30–35 MPa.

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The simulation results of the thermal stabilization of polyacrylonitrile pressed organomorphic frame samples are presented. The local temperature maximum in the sample depth due to an exothermic oxidation reaction was confirmed. The possibility of the avalanche exothermic effect, which can lead to a sample burnout, is demonstrated theoretically. The analysis of the influence of the initial fiber oxidation degree on the sample temperature state have been carried out.

Simulation and analysis of thermophysical processes in PAN-fiber-based pressed samples that occurs during thermal stabilization were carried out. It is significant fact from the heat transfer point of view that the heat stabilization process proceeds with a definite exothermic effect. Herewith a strongly pronounced coupling between both the intensity of heat generation and the temperature level and heating rate at each point of the sample was observed. The influence of the main factors that effects on the sample temperature state, such as the density and thermal conductivity of the preform material, also the rate constants of the thermal stabilization process, was studied. The experimental data of the sample temperature state in the thermal stabilization process is presented and was compared with the analysis results.