H. Preiss et al., Synthesis of polymeric titanium and zirconium precursors and preparation of carbide fibres and films, J MATER SCI, 33(19), 1998, pp. 4697-4706
Polymeric precursors for carbothermal reactions were prepared from the chel
ate derivatives of titanium and zirconium alkoxides L2M(OR)(2) (L is an ace
tylacetonato or ethyl acetoacetato group) in alcohols by reaction with orga
nic compounds having two or more reactive OH groups, such as ethylene glyco
l, saccharose, tartaric acid or dihydroxybenzenes. These organic groups act
as bridging ligands in transesterification and condensation polymerization
yielding either spinnable viscous solutions or elastic gels. The rheologic
al properties of the concentrated solutions allowed for the preparation of
polymer fibres and films. At temperatures up to 1600 degrees C, bulk precur
sors as well as fibres and films were thermally converted into carbide powd
ers, films or coatings. The structural transformations of the polymeric mat
erials into the carbides were investigated using thermogravimetric-differen
tia I thermal ana lyses (TGA-DTA), X-ray diffraction (XRD), scanning electr
on microscopy (SEM), Fourier transform infra-red (FTIR) analysis and Raman
spectroscopy. (C) 1998 Kluwer Academic Publishers.