A method of making a composite ceramic fiber from pre-ceramic polymers

A method of making a composite ceramic fibre comprising forming a self-supporting composite polymeric fibre by the conjugate spinning of at least two dissimilar pre-ceramic polymers to form a composite core-sheath fibre having a continuous core and a surrounding sheath respectively formed from said dissimilar polymers, wherein each of said polymers includes repeating units containing a ceramic-forming element other than carbon and oxygen, and thereafter pyrolysing the spun fibre to form a composite ceramic fibre having regions with dissimilar ceramic compositions derived from the respective dissimilar polymers, and

• wherein said spun core-sheath fibre is chopped before pyrolysis by pressing together the opposite sides of the sheath in such a way that the continuous core polymer is interrupted, and the sheath polymer is closed and sealed over the parted core polymer ends, before the sheath polymer is cut to separate the individual short fibres.

A method of making a composite ceramic fibre comprising forming a self-supporting composite polymeric fibre by the conjugate spinning of at least two dissimilar pre-ceramic polymers, wherein each of said polymers includes repeating units containing a ceramic-forming element other than carbon and oxygen, and thereafter pyrolysing the spun fibre to form a composite ceramic fibre having regions with dissimilar ceramic compositions derived from the respective dissimilar polymers, and

• wherein the pyrolysis step is performed by passing the spun pre-ceramic fibre to a controlled atmosphere furnace, and pyrolysing the fibre in the furnace, and
• wherein the spun fibre is pyrolysed in a continuous helical groove on a rotating refractory cylinder.