Thermal properties and mechanical properties of density gradient carbon/carbon composites

As a kind of high performance thermal-resistant composite, carbon/carbon composites have the highest mechanical strength in the temperature above 1600^DDGC, and the research of C/C gradient materials will extend the application of C/C as a kind of heat insulation in high temperature. To get some information concerning the application of density gradient materials, thermal conductivities (with different densities and under various temperatures) were measured. In order to provide a theory in the application of density gradient carbon/carbon composites (C/C), the relationships between thermal conductivity and density/temperature of these C/C composites were summarized; the relationship between the thermal conductivity and the density approximately accorded with linearity in the experimental range. It is found that density gradient C/C composite have higher flexural strength and lower thermal conductivity than uniform C/C composites, which infers that the materials have a great superiority in heat insulation and structural application.