Composite material, heat-absorbing component, and method for producing the composite material

A heat-absorbing component, comprising:

• at least one surface formed from a composite material comprising a matrix of fused silica in which regions of a phase containing silicon in elemental form have been embedded wherein said silicon is present as a silicon alloy or as doped or undoped silicon, and wherein the phase containing said silicon in elemental form is present in a weight fraction that is at least 1% but not more than 5%,
• wherein the composite material is impervious to gas, has a closed porosity of less than 0.5% and a specific density of at least 2.19 g/cm3, and, at a temperature of 1000° C., has a spectral emissivity of at least 0.7 for wavelengths between 2 and 8 μm measured with a path length of 1 mm;
• and
• wherein the matrix consists essentially of fused silica having a hydroxyl group content of not more than 30 ppm by weight.