INVESTIGATION OF THE DENSITY OF CCCM AND ITS INFLUENCE ON SPECIFIC VOLUME ELECTRICAL RESISTIVITY

This article investigates the structure and properties of carbon-carbon composite materials (CCCM), where the carbon matrix is formed by the deposition of pyrolytic carbon in the porous volume of a carbon fiber preform using thermogradient gas-phase pyrolysis densification technologies. The results of studying the apparent density of CCCM by hydrostatic methods and its influence on the specific volume electrical resistivity of the material are presented. The conducted study established that the specific volume electrical resistivity of CCCM significantly depends on a number of factors, one of which is the material density. An increase in the apparent density of the material leads to a decrease in its porosity, which, in turn, affects the decrease in electrical resistance. It is emphasized that density control becomes a key factor in ensuring optimal electrical conductivity of carbon-carbon composite materials. It is shown that the densification of CCCM significantly improves the structure of blanks and crucibles, increasing their physical and operational characteristics. This makes them more suitable for use in high-temperature conditions, aggressive environments, in the production of heat-resistant components and other high-tech areas. Repeated densification of CCCM revealed a significant impact on the quality of the material. It is shown that an increase in density after additional densification leads to a decrease in porosity, improvement of mechanical properties and a change in the pore distribution in the material, which positively affects its porosity and strength. Bench tests of model samples made of CCCM showed that an increase in the apparent density of the material leads to a decrease in its electrical resistance. To ensure control in industrial practice, an effective and affordable method for assessing the degree of completion of crystalline transformations and determining the degree of graphitization during high-temperature treatment of carbon materials is recommended to compare the specific volume electrical resistivity of the working sample with the reference one. The importance of controlling the parameters of density, porosity, and electrical resistance to optimize technological processes and ensure high quality of final products is emphasized. The obtained data can be useful for applications in various industries.