Process of producing a ceramic/fiber composite using a molten polysilazone
AssigneeHoechst Aktiengesellschaft
InventorsMarcellus Peuckert, Martin Bruck, Thomas Gerdau, Tilo Vaahs, Hans-Jerg Kleiner, Fritz Aldinger
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Abstract
The invention relates to a process for the production of a ceramic/fiber composite. The process comprises impregnating fibers with a molten polysilazane in a first step, converting the polysilazane in the fibers into the infusible state in a second step and, in a third step, heating the impregnated fibers to 800.degree. to 2000.degree. C. in an atmosphere of nitrogen, noble gas, or ammonia.
Claims9
A process for the production of a ceramic/fiber composite, which comprises the steps of (a) impregnating fibers with a molten polysilazane wherein said molten polysilazine is represented by the general formula (I) ##STR4## in which x and y represent the mole fractions of the two structural units and where x+y=1 and x=0.7 to 0.95;
- or by the general formula (II) ##STR5## in which the free valencies of the nitrogen atoms are saturated with H atoms or silyl radicals ##STR6## and in which R, R', R" and R* denote alkyl or alkenyl groups having up to 6 carbon atoms;
- and a, b and c denote the mole fractions of the respective structural units;
- b) converting the polysilazine in the fibers into the infusible state using NH.sub.3, hexamethylenetetramine, an amine or a chlorosilane of the general formula (CH.sub.3).sub.n SiCl.sub.m, in which n+m=4 and n=1,2 or 3, and c) heating the impregnated fibers to 800.degree. to 2000.degree. C. in an atmosphere selected from the group consisting of nitrogen, noble gas and ammonia.
Dependencies are inferred from the claim text.