4.
    发明专利
    未知

    公开(公告)号:DE58908181D1

    公开(公告)日:1994-09-15

    申请号:DE58908181

    申请日:1989-11-29

    Applicant: HOECHST AG

    Abstract: The invention relates to novel chlorine-containing silazane polymers, to their preparation, their further processing to ceramic material containing silicon nitride, and this material itself. In order to prepare the chlorine-containing silazane polymers, oligosilazanes of the formula (I) in which a>0, b>/=0 and n is about 2 to about 12, are reacted with at least one of the chlorosilanes Cl2R4Si-CH2-CH2-SiR4Cl2, Cl3Si-CH2-CH2-Sir5Cl2, R6SiCl3 or R7SiHCl2 at 30 DEG C. to 300 DEG C., where, independently of one another, R1 and R2=H, C1-C6-alkyl or C2-C6-alkenyl, R3, R4, R5, R6 and R7=C1-C6-alkyl or C2-C6-alkenyl and where if b=0 the reaction with R7SiHCl2, if R7=C1-C6-alkyl and none of the other chlorosilanes is present, is to be excluded. The chlorine-containing silazane polymers according to the invention can be converted by reaction with ammonia into polysilazanes, which in their turn can be pyrolyzed to form ceramic materials containing silicon nitride.

    5.
    发明专利
    未知

    公开(公告)号:DE3939448A1

    公开(公告)日:1990-06-07

    申请号:DE3939448

    申请日:1989-11-29

    Applicant: HOECHST AG

    Abstract: The invention relates to a high-strength ceramic composite, in particular made from silicon nitride, a process for its preparation and its use. The process comprises impregnating an open-pore matrix with a molten polysilazane in a first step and, in a second step, heating the impregnated matrix to 800 DEG to 2500 DEG C. under a blanketing gas, such as nitrogen or a noble gas, or to 800 DEG to 1500 DEG C. under a gas containing ammonia. The high-strength ceramic composite prepared can be used as a component to be subjected to high thermal, mechanical or corrosive stress.

    7.
    发明专利
    未知

    公开(公告)号:DE3840770A1

    公开(公告)日:1990-06-07

    申请号:DE3840770

    申请日:1988-12-03

    Applicant: HOECHST AG

    Abstract: The invention relates to novel polymeric ethylene-bridged chlorosilazanes, their preparation, their further processing to give silicon nitride containing ceramic material, and to this material itself. For the preparation of the polymeric chlorosilazanes, oligosilazanes of the formula (I) … … are reacted with at least one of the chlorosilanes … … R SiCl3 or R SiHCl2, where R to R are C1-C6-alkyl or C2-C6-alkenyl groups which can be identical or different. … The polymeric chlorosilazanes according to the invention can be converted by reaction with ammonia into polysilazanes which, in turn, can be pyrolysed to give silicon nitride-containing ceramic materials.

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