be at least partially attributable to pyrolysis of the filler in the matrix the average resulting pore size amounts to less than 200 nm for example 5 nm to 100 nm depending on the average particle size of the filler used in addition to the silicon dioxide described above other oxides nitrides or carbides of silicon aluminum titanium zirconium boron tungsten vanadium hafnium niobium tantalum or molybdenum or a mixture thereof e g in the form of oxycarbides oxynitrides carbonitrides or oxycarbonitrides may also be used as nanoscale fillers in addition the nanoscale filler may be a metallic powdered filler and or a filler containing gold palladium platinum rhodium or iridium e g in the form of a sol with nanoscale colloids contained therein or a suspension containing this metallic filler if the nanoscale filler at first is to be at least mostly decomposed in pyrolysis to form pores in the composite material an organic filler such as nanoscale carbon particles or nanoscale carbon black or nanoscale organic polymers may be suitable as the filler depending on the amount of the filler the pyrolysis temperature and the duration of pyrolysis the open porosity of the ceramic composite material obtained with these fillers may be adjusted to levels between 1 and 50 the pyrolysis for example being followed by aging in an oxygen containing atmosphere which allows carbon to burn off as thoroughly as possible suitable.