CA2004406A1
Expired / Lapsed
CA
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Ceramic/fiber composite and process for its production
Assignee: Hoechst AG
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Filing: 1989-12-01
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Granted: —
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Expires: 2009-12-01
Abstract
Abstract Abstract Ceramic/fiber composite and process for its production The invention relates to a ceramic/fiber composite and a process for its production. 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 to 2000°C in an atmosphere of nitrogen, noble gas, or ammonia.
Inventors
- 👤 Marcellus Peuckert
- 👤 Martin Bruck
- 👤 Thomas Gerdau
- 👤 Tilo Vaahs
- 👤 Hans-Jerg Kleiner
- 👤 Fritz Aldinger
Bibliographic Details
Application Number
—
Jurisdiction
CA
Data Source
google_patents
Last Synchronized
2026-10-30 16:35
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/589; C04B35/71; C04B35/78; C04B35/80; C04B41/45; C04B41/4505; C04B41/455; C04B41/4554; C04B41/4584; C04B41/50; C04B41/5053; C04B41/5062; C04B41/5066; C04B41/80; C04B41/81; C04B41/85; C04B41/87
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
84 words
A process for the production of a ceramic/fiber composite, which 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, using NH3, Urotropin, an amine or a chlorosilane of the general formula (CH3)nSiClm, in which n + m - 4 and n = 1, 2 or 3, and, in a third step, heating the impregnated fibers to 800 to 2000°C in an atmosphere of nitrogen, noble gas or ammonia.
Claim 2
Dependent Claim
84 words
A process for the production of a ceramic/fiber composite, which 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, using NH3, Urotropin, an amine or a chlorosilane of the general formula (CH3)nSiClm, in which n + m - 4 and n = 1, 2 or 3, and, in a third step, heating the impregnated fibers to 800 to 2000°C in an atmosphere of nitrogen, noble gas or ammonia.
Claim 3
Dependent Claim
45 words
The process as claimed in claim 1, wherein a molten polysilazane of the general formula (I) is used, 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.
Claim 4
Dependent Claim
75 words
The process as claimed in claim 1, wherein a molten polysilazane of the general formula (II) is used, in which the free valencies of the nitrogen atoms are saturated with H atoms or silyl radicals R*SiXN< (X = H, Cl, N<, CH2CH2Si-) 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.
Claim 5
Dependent Claim
24 words
The process as claimed in claim 3, wherein R, R', R" and R* are alkyl or alkenyl groups having up to 3 carbon atoms.
Claim 6
Dependent Claim
9 words
The process as claimed in claim 3, wherein R=R'=R"=R*=CH3.
Claim 7
Dependent Claim
25 words
The process as claimed in one of claims l to 4, wherein fibers of C, SiC, Si3N4 or Al2O3 or carbon fiber-reinforced carbon are used.
Claim 8
Dependent Claim
75 words
The process as claimed in one of claims 1 to 5 t wherein, a molten polysilazane is first spun into fibers, these fibers are then converted by heat treatment at 800 to 1600°C into Si3N4 fibers, a two-dimensional structure is produced from the latter and said structure is then impregnated with the same or a different molten polysilazane, the polysilazane is converted to the infusible state and the product is heated to 800 to 2000°C.
Claim 9
Dependent Claim
31 words
The process as claimed in one of claims 1 to 7, wherein the sequence of the three process steps is carried out at least twice in succession on the same fibers.
Claim 10
Dependent Claim
52 words
The process as claimed in one of claims 1 to 8, wherein compounds of magnesium, aluminum, yttrium or of a rare earth metal, singly or as a mixture, are dissolved in the molten polysilazane as filler for the fibers and the fibers are impregnated with this solution instead of with pure polysilazane.
Claim 11
Dependent Claim
28 words
The process as claimed in claim 9, wherein the nitrates, alcoholates, acetates or acetylacetonates of the said metals are used, singly or as a mixture, as the filler.
Claim 12
Dependent Claim
17 words
Ceramic/fiber composite obtainable in accordance with the process as claimed in one of claims 1 to 10.
Claim 13
Dependent Claim
76 words
A ceramic/fiber composite obtainable in accordance with the process as claimed in one of claims 1 to 11, composed of fibers and a ceramic amorphous or partly crystalline matrix, in which the matrix contains 45 to 60% by weight Si, 30 to 40% by weight N, 0 to 25% by weight C and 0 to 20% by weight O, and is in the form of crystalline Si3N4 to the extent of more than 30% by weight.
Claim 14
Dependent Claim
92 words
A process for coating a ceramic/fiber composite, wherein a ceramic/fiber composite according to claim 11 is mechanically processed and is then coated with molten polysilazane in a first step, the polysilazane is converted into the infusible state, in a second step using NH3, Urotropin, an amine or a chlorosilane of the general formula (CH3)nSiClm, in which n + m = 4 and n = 1, 2 or 3, and, in a third step the coated ceramic/fiber composite is heated to 800 to 2000°C in an atmosphere of nitrogen, noble gas or ammonia.
Claim 15
Dependent Claim
15 words
A coated ceramic/fiber composite obtainable in accordance with the process as claimed in claim 13.
References Cited (Backward Citations)
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