Published online by Cambridge University Press: 21 February 2011
We report on an alternative route to quaternary ceramics which can beprepared by polycocondensation of commercially available polysilazanes withthe appropriate alkyl amides (M(NRR')X with M = B or P andsubsequent pyrolysis in argon atmosphere at 1000°C. Ceramic monoliths areobtained if the modified polysilazane is crosslinked at 400°C for 3 h. Afterball-milling, sieving and cold isostatic pressing the green body is directlypyrolysed to the appropriate monolith. The obtained material is amorphous toX-ray-diffraction. Investigations by electron spectroscopie imaging (ESI) inTEM indicate a homogeneous distribution of the elements M, Si, C and N (M =B, P) within a resolution of 2 nm. Upon annealing at elevated tempertures ina nitrogen atmosphere crystallization of the appropriate thermodynamicallystable phases occurs around 1400°C yielding a micro/nano-, nano/nano- ormicro/microcrystalline microstructure with design-tailored propertiesdepending on the element M.