Hoechst Aktiengesellschaft

Institut Fuer Mikrotechnik Gmbh

Tilo Vaahs

Martin Bruck

Marcellus Peuckert

Hans-Jerg Kleiner

Fritz Aldinger

Thomas Gerdau

Ude Scheunemann

Thomas Stehlin

Jurgen Theis

Werner H Russ

Andreas Schrell

Wolfgang Ehrfeld

Gunter Petzow

Thomas Riehm

Wolfgang Bocker

Manfred Lacher

Ludwig Giebel

Marcellus Feuckert

Ralf Riedel

Martin Sehr

A process for producing a ceramic having a microstructured surface with a surface profile depth of less than 1 micron, measured by the atomic force microscopy, comprising preparing a polymeric precursor material, shaping the precursor material into a structured mold insert of an inherently stable mold insert material having a structured surface geometry corresponding with the microstructured surface of the ceramic to form a shaped precursor material, the shaped precursor material being rendered infusible by chemical crosslinking, and wherein the inherently stable mold insert material is selected from materials having sufficient strength for structuring and high molding accuracy, and pyrolyzing the shaped precursor material, whereby the ceramic having the microstructured surface is obtained.

Process for producing ceramic microstructures from polymeric precursors

A transparent molded article for optical applications made from silicon nitride and a coating thereon of oxidic silicon nitride formed by chemical reaction of the silicon nitride with oxygen. The moldings can be shaped, depending on the area of application, to give various articles, for example optical waveguides, prisms, sensor elements or lenses, and are used in all areas where high optical demands are made.

Optical waveguide moldings made from silicon nitride and a method of

A process for dyeing textile fiber materials with water-soluble dyestuffs, in particular anionic dyestuffs, and of these in particular those having a fiber-reactive group, in which the dyeing is carried out using low-electrolyte or entirely electrolyte-free and/or low-alkali or entirely alkali-free dye liquors or printing pastes and a fiber material which has been modified with a silane compound containing amino groups is used as the textile material. The fiber material is modified by applying the silane compound containing amino groups to the material in aqueous solution and subjecting the impregnated material to a heat treatment. Novel silane compounds which contain a secondary amino group and can likewise be employed for the purpose mentioned are furthermore described.

Process for dyeing fiber materials modified with silanes, the

A process for the preparation of optical materials from silicon nitride by pyrolysis of polymeric silazanes, by pressing the pulverulent polymeric silazanes to give moldings before the pyrolysis or first dissolving the polymeric silazanes in an organic solvent, drawing fibers from this solution and pyrolyzing these fibers after evaporation of the solvent, or by melting polymeric silazanes, casting, injection-molding or extruding this melt to give moldings and subsequently pyrolyzing the moldings. An oxidic coating is produced on the silicon nitride molding in an oxygen-containing atmosphere during or after the pyrolysis. The pyrolysis can be carried out at 800.degree.-1000.degree. C. in an atmosphere containing ammonia or an ammonia/inert gas mixture.

Optical moldings made from silicon nitride, and a process for their

The invention relates to fiber composite materials and a process for their preparation. The process comprises impregnating fibers with a molten polysilazane in a first step, converting the polysilazane in the fibers into the non-fusible state in a second step, and heating the impregnated fibers to 800.degree. to 2000.degree. C. in a nitrogen, noble gas or ammonia atmosphere in a third step.

Fiber-reinforced composite materials and process for their preparation

The invention relates to novel polysubstituted chlorine-containing silazane polymers, to their preparation, to their processing to form ceramic material containing silicon nitride, and to said material itself. The chlorine-containing silazane polymers are prepared by reating oligosilazanes of formula (I) ##STR1## in which at least one of the indices a or b and at least one of the indices c or d are not equal to 0 and n is about 2 to about 12, with at least one of the chlorosilanes Cl.sub.2 R.sup.6 Si--CH.sub.2 CH.sub.2 --SiR.sup.6 Cl.sub.2, Cl.sub.3 Si--CH.sub.2 CH.sub.2 --SiR.sup.7 Cl.sub.2, R.sup.8 SiCl.sub.3 or R.sup.9 SiHCl.sub.2 at 30.degree. C. to 300.degree. C., where the radicals independently of one another have the following meanings: R.sup.1, R.sup.2, R.sup.4 =H, C.sub.1 -C.sub.6 alkyl or C.sub.2 -C.sub.6 alkenyl and R.sup.3, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9 =C.sub.1 -C.sub.6 alkyl or C.sub.2 -C.sub.6 alkenyl. The polysubstituted chlorine-containing silazane polymers according to the invention can be converted into polysilazanes by reaction with ammonia, and these in turn can be pyrolyzed to form ceramic materials containing silicon nitride.

Polysubstituted chlorine-containing silazane polymers, process for their

The invention relates to novel polymeric hydridochlorosilazanes, to their preparation, to their processing to form ceramic materials containing silicon nitride, and to said materials themselves. The polymeric hydridochlorosilazanes are prepared by reacting oligohydridoorganosilazanes of the general formula (R.sup.1 SiHNH).sub.n, in which n is about 3 to about 12, with at least one of the chlorosilanes R.sup.2 SiHCl.sub.2, R.sup.3 SiCl.sub.3, Cl.sub.2 R.sup.4 Si--CH.sub.2 CH.sub.2 --SiR.sup.4 Cl.sub.2 or Cl.sub.3 Si--CH.sub.2 CH.sub.2 --SiR.sup.5 Cl.sub.2 at 30.degree. C. to 300.degree. C., where the radicals independently of one another have the following meanings:

Polymeric hydridochlorosilazanes, process for their preparation, ceramic

The invention relates to novel silazane polymers containing SiCl groups, to their preparation, to their conversion into silicon nitride-containing ceramic material, and to this material itself. In order to prepare the silazane polymers containing SiCl groups, .alpha.,.omega.-chlorosilazanes of the formula I ##STR1## in which m has a value of from 1 to 12 and --(Si) is a silyl radical of the formula --SiHR.sup.1 Cl, --SiR.sup.2 R.sup.3 Cl, --SiR.sup.4 Cl.sub.2, --SiR.sup.5 Cl-CH.sub.2 CH.sub.2 -SiR.sup.5 Cl.sub.2 or --SiCl.sub.2 -CH.sub.2 CH.sub.2 -SiR.sup.6 Cl.sub.2, and R is C.sub.1 -C.sub.6 -alkyl or C.sub.2 -C.sub.6 -alkenyl and, independently of one another, R.sup.1 -R.sup.6 are H, C.sub.1 -C.sub.6 -alkyl or C.sub.2 -C.sub.6 -alkenyl, to a temperature of from 100.degree. C. to 400.degree. C. The silazane polymers according to the invention containing in SiCl groups can be reacted with ammonia to give polysilazanes, which can themselves be pyrolyzed to give silicon nitride-containing ceramic materials.

Silazane polymers containing SiCl groups, process for their preparation,

The invention relates to novel polymeric chlorosilazanes, to their preparation, to their processing to form ceramic material containing silicon nitride, and to said material itself. The polymeric chlorosilazanes are prepared by reacting a mixture of oligosilazanes of formula (I) ##STR1## in which n is about 2 to about 12, and oligosilazanes of formula (II), (RSiHNH).sub.m, in which m is about 3 to about 12, with at least one of the chlorosilanes Cl.sub.2 R.sup.2 Si--CH.sup.2 --CH.sub.2 --SiR.sup.2 Cl.sub.2, Cl.sub.3 Si--CH.sub.2 --CH.sub.2 --SiR.sup.3 Cl.sub.2, R.sup.4 SiCl.sup.3 or R.sup.5 SiHCl.sub.2 at 30.degree. C. to 300.degree. C., where R and R.sup.1 to R.sup.5 are C.sub.1 -C.sub.6 alkyl or C.sub.2 -C.sub.6 alkenyl groups which can be identical or different. The polymeric chlorosilazanes according to the invention can be converted into polysilazanes by reaction with ammonia, and these in turn can be pyrolyzed to form ceramic materials containing silicon nitride.

Polymeric chlorosilazanes, process for their preparation, ceramic

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.

Process of producing a ceramic/fiber composite using a molten

The invention relates to a novel sinterable ceramic powder, to its preparation and to its further processing to give a silicon nitride ceramic, and to this material itself and its use. The sinterable ceramic powder is produced by melting a polysilazane or dissolving it in an organic solvent, suspending a powdered sinter aid in this melt or solution, then pyrolyzing the melt, or the residue obtained after evaporation of the solvent, at 500.degree. to 1600.degree. C. in a protective gas atmosphere, the polysilazane either

Sinterable ceramic powder, process for its production, silicon nitride

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.degree. to 2500.degree. C. under a blanketing gas, such as nitrogen or a noble gas, or to 800.degree. to 1500.degree. 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.

High-strength ceramic composite, process for its preparation and its use

The invention 1204 to a process for the preparation of .alpha., .omega.-chlorosilazanes which comprises reacting an oligohydridoorganylsilazane of the formula [--RSiH--NH--].sub.n in which n is from about 3 to about 12 with at least one of the chlorosilanes R.sup.1 HSiCl.sub.2, R.sup.2 R.sup.3 SiCl.sub.2, R.sup.4 SiCl.sub.3, Cl.sub.2 R.sup.5 SiCl.sub.2 CH.sub.2 SiR.sup.5 Cl.sub.2 and Cl.sub.3 SiCH.sub.2 CH.sub.2 SiR.sup.6 Cl.sub.2 where R is C.sub.1 -C.sub.6 -alkyl or C.sub.2 -C.sub.6 -alkenyl and,independently of one another, R.sup.1 -R.sup.6 are H, C.sub.1 -C.sub.6 alkyl, or C.sub.2 -C.sub.6 -alkenyl, at from -20.degree. C. to +50.degree. C. In addition, the invention relates to the novel .alpha., .omega.-chlorosilazanes obtainable by this process.

.alpha., .omega.-chlorosilazanes, and a process for their preparation

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) ##STR1## in which a &gt;0, b.gtoreq.0 and n is about 2 to about 12, are reacted with at least one of the chlorosilanes Cl.sub.2 R.sup.4 Si--CH.sub.2 --CH.sub.2 --SiR.sup.4 Cl.sub.2, Cl.sub.3 Si--CH.sub.2 --CH.sub.2 --SiR.sup.5 Cl.sub.2, R.sup.6 SiCl.sub.3 or R.sup.7 SiHCl.sub.2 at 30.degree. C. to 300.degree. C., where, independently of one another,

Chlorine-containing silazane polymers, process for their preparation,

The invention relates to novel polysilazanes, the preparation thereof, the further processing thereof to form silicon nitride-containing ceramic material, and this material itself. In order to prepare the polysilazanes, dialkylaminoorganyldichlorosilanes of the formula RSiCL.sub.2 --NR'R' are reacted with ammonia. The polysilazanes can then be pyrolyzed to form silicon nitride-containing ceramic material. The polysilazanes according to the invention dissolve in customary aprotic solvents.

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Kelkheim, Germany

Tilo Vaahs