Abstract: This invention provides a composite article comprising mullite bubbles dispersed in one of a glass matrix and a glass-ceramic matrix, and a method of making the same. The composite ceramic article of the present invention is useful in applications requiring a material having a low dielectric constant, low dissipation factor, thermal expansion properties compatible with silicon, and good mechanical strength. The composite ceramic article of the present invention is particularly useful as a substrate for thick film circuits, housings for integrated circuit assemblies (i.e., covers), and materials such as gyrotron windows, that require transparency to microwaves or millimeter waves, in addition to acceptable power transmission efficiencies.

Abstract: A ceramics composite material containing crystallized glass as the matrix and fibers or whiskers of ceramics as a reinforcement material, is obtained by melting original glass to form crystallized glass, compounding the same with fibers or whiskers of oxide ceramics and thereafter crystallizing the original glass. This ceramics composite material does not form any voids and can easily contain at least 50 volume percent of the reinforcement material, whereby a good mechanical strength and fracture toughness are achieved. In the compounding step, the content of the reinforcement can be further increased by forcing out any excess part of the original glass from the reinforcement material by applying pressure to a substance obtained by mixing the original glass with the reinforcement. Further, the ceramics composite material can be efficiently formed into a desired configuration by heating because the original glass flows viscously.

Abstract: A ceramic material suitable for packaging of large scale integrated circuit is produced by the process of forming a mixture of a powdered glass ceramic material which is a glassy precursor to cordierite ceramic material, formed by the steps which are as follows:a. Mix tetragonal phase material selected from the group consisting of zirconia or hafnia powder containing a stabilizing oxide compound selected from the group consisting of MgO, CaO and Y.sub.2 O.sub.3 and a glass frit powder or frit of a glassy precursor of cordierite glass ceramic to yield a suspension of solids. Preferably, a binder is included.b. Disperse the suspended solids to yield a dispersion of the zirconia or hafnia with the stabilizing oxide compound and the glassy precursor.c. Densify the dispersion of zirconia or hafnia with the stabilizing oxide compound and the glassy precursor by a sintering heat treatment at a temperature of about 840.degree. C.

Abstract: A light transmitting sintered body of cordierite has a composition equal or close to the stoichiometric composition of cordierite which is represented as 2MgO.2Al.sub.2 O.sub.3.5SiO.sub.2, consists mainly of a phase of cordierite crystals, and has a total transmittance of at least 20%. A method of preparing it is also disclosed.

Abstract: A substrate having a low dielectric constant for use with electronic devices consisting essentially of porous crystalline glass. The composition of the crystalline glass is represented by the formula X-Al.sub.2 O.sub.3 -SiO.sub.2, where X is one or more of the metal oxides ZnO, MgO, Li.sub.2 O, ZrO.sub.2, B.sub.2 O.sub.3, P.sub.2 O.sub.5, Y.sub.2 O.sub.3 and BaO. The crystalline glass may also include a filler material such as a ceramic powder or non-glass material. The substrate initially has a particle size of approximately 5 microns or less, which provides a high mechanical strength to the substrate even at high porosities.

Abstract: A ceramic material suitable for packaging of large scale integrated circuits is produced by the process of forming a mixture of a powdered glass ceramic material which is a glassy precursor to cordierite ceramic material, formed by the steps which are as follows:a. Mix tetragonal phase material selected from the group consisting of zirconia of hafnia powder containing a stabilizing oxide compound selected from the group consisting of MgO, CaO and Y.sub.2 O.sub.3 and a glass frit powder or frit of a glassy precursor of cordierite glass ceramic to yield a suspension of solids. Preferably, a binder is included.b. Disperse the suspended solids to yield a dispersion of the zirconia or hafnia with the stabilizing oxide compound and the glassy precursor.c. Densify the dispersion of zirconia or hafnia with the stabilizing oxide compound and the glassy precursor by a sintering heat treatment at a temperature of about 840.degree. C.

Abstract: This invention is directed toward of a glass-ceramic article consisting essentially, expressed in terms of weight percent on the oxide basis, of about 64-70% SiO.sub.2, 18-22% Al.sub.2 O.sub.3, 3.3-4% Li.sub.2 O, 2-5% ZnO, 0-2% MgO, 1.5-3.5% ZrO.sub.2, 0.5-2.5% TiO.sub.2, 3.5-4.5% ZrO.sub.2 +TiO.sub.2, 0.5-1.5% As.sub.2 O.sub.5 and 0-0.5% SnO.sub.2. The glass-ceramic article disclosed herein, is comprised of adjacent areas which exhibit visible transmissions ranging from transparent-to-opaque. The transparent areas are clear, transparent and essentially colorless and contain stuffed .beta.-quartz as essentially the sole crystal phase. On the other hand, the translucent-to-opaque areas contain .beta.-spodumene as the predominant crystal phase with a minor amounts of gahnite crystals resulting from the thermal transformation of said stuffed .beta.-quartz. This gahnite phase is present in an amount sufficient to compensate for the transformation of said stuffed .beta.-quartz to .beta.

Abstract: Glass compositions containing oxygen and nitrogen prepared by melting admixture of magnesia and/or a magnesium silicate, silica and an aluminum nitride produced by reacting ammonia with aluminum oxide, have the formula:Mg.sub.x Si.sub.y Al O.sub.u N.sub.v (1)in which 0.25.ltoreq.x.ltoreq.2.50, 1.25.ltoreq.y.ltoreq.3.50, 3.75.ltoreq.u.ltoreq.10.50, and 0.05.ltoreq.v.ltoreq.0.75, with the proviso that 2x+4y+3=2u+3v; the subject glass compositions are thermally converted into vitroceramics having the same formula and including a single cordierite crystalline phase, which vitroceramics are well adapted for the production of composite shaped articles.

Abstract: Fiber-reinforced ceramic matrix composite products comprising boron-nitride-coated reinforcing silicon carbide fibers disposed in a substantially non-porous alkaline earth aluminosilicate glass-ceramic matrix are disclosed, the matrix comprising triclinic anorthite (CaO,SrO.Al.sub.2 O.sub.3.2SiO.sub.2) as the principal crystal phase and the products exhibiting unexpectedly good resistance to high-temperature degradation.

Abstract: A fiber-reinforced ceramic matrix composite article comprising fiber-reinforced surface portions disposed on a ceramic core, the core differing in composition and high temperature properties from the surface portions and the fibers present in the surface portions being of a type normally subject to oxidative deterioration at high temperature, wherein the fibers in the surface portion are provided with protection from high temperature oxidative deterioration such that excellent strength and resistance to high temperature embrittlement are achieved for the composite as a whole.

Abstract: There is disclosed a sintering arrangement for enhancing the removal of carbon from multilayer ceramic substrate laminate during the sintering thereof. A multilayer ceramic substrate laminate having metallic lines and vias is provided with a reducible metal oxide in close proximity to the substrate laminate. The multilayer ceramic substrate laminate contains a polymeric binder which upon heating depolymerizes into carbon. The substrate laminate is sintered in an atmosphere which is reducing with respect to the reducible metal oxide and which is oxidizing with respect to the carbon.

Abstract: Composite shaped articles, well adapted for aerospace applications, include a glass-ceramic and an effective amount of a reinforcing agent therefor, preferably a fibrous and ceramic reinforcing agent, such glass-ceramic matrix being based on silica, alumina, an alkaline earth metal oxide and a rare earth oxide, in the following proportions by weight relative to the total weight of the matrix:5%.ltoreq.MO.ltoreq.40%25%.ltoreq.SiO.sub.2 .ltoreq.70%15%.ltoreq.Al.sub.2 O.sub.3 .ltoreq.70%5%.ltoreq.rare earth oxide.ltoreq.70%wherein M represents an alkaline earth metal.

Abstract: A method of preparing colored crystallized glass is disclosed, comprising the steps of:(a) adding to a crystallized glass material from 0.1 to 10 parts by weight of a coloring agent per 100 parts by weight of the crystallized glass material, said coloring agent having been prepared by preliminarily burning in an oxidizing atmosphere at a temperature of from 1,000.degree. to 1,400.degree. C. for at least 1 hour from 0.05 to 7 parts by weight of Fe.sub.2 O.sub.3, from 0.03 to 5 parts by weight of CoO, and at least one oxide selected from the group consisting of from 0.01 to 2.5 parts by weight of NiO and from 0.01 to 2.5 parts by weight of Cr.sub.2 O.sub.3, the amounts of the components of the coloring agent being given in parts by weight per 100 parts by weight of the crystallized glass material;(b) molding the resulting mixture under a pressure of from 500 to 3,000 kg/cm.sup.2 ; and(c) calcining the molded mixture to effect crystallization heat treatment.

Abstract: A composition for making dielectric layers having low dielectric constant, the composition comprising an admixture of finely divided solids comprising lead-free amorphous borosilicate glass and cordierite glass. The dielectric layers are useful in circuits, especially multilayers circuits for high density applications.

Abstract: A ceramic material suitable for packaging of large scale integrated circuits is produced by the process of forming a mixture of a powdered glass ceramic material which is a glassy precursor to cordierite ceramic material, formed by the steps which are as follows:a. Mix tetragonal phase material selected from the group consisitng of zirconia or hafnia powder containing a stabilizing oxide compound selected from the group consisting of MgO, CaO and Y.sub.2 O.sub.3 and a glass frit powder or frit of a glassy precursor of cordierite glass ceramic to yield a suspension of solids. Preferably, a binder is included.b. Disperse the suspended solids to yield a dispersion of the zirconia or hafnia with the stabilizing oxide compound and the glassy precursor.c. Densify the dispersion of zirconia or hafnia with the stabilizing oxide compound and the glassy precursor by a sintering heat treatment at a temperature of about 840.degree. C.

Abstract: Compositionally triphasic nanocomposite gel is made by mixing two or more sols of ceramic precursor oxides. Such gel is then dried and ground to a fine powder which is pressed into compact bodies. The compact bodies are thereafter fired in a sintering oven at from 1100.degree. C. to 1400.degree. C. and, aided by the heat of reaction of the two or more nono gel powders, the (heterogeneous) mixture of such powders crystallizes into a homogeneous crystalline ceramic of .alpha.-cordierite at up to 100% of theoretical density. Thus, novel method of manufacture and novel ceramic end-product are provided.

Abstract: There is disclosed a cordierite-type glass-ceramic article having a controlled gray coloration, and a method of producing such article by employing titania as the nucleating agent and firing in a reducing atmosphere, preferably a hydrogen-containing atmosphere, at 500.degree.-900.degree. C. for 2-8 hours.

Abstract: There is disclosed a sintered, alpha-cordierite solid solution glass-ceramic body in which the properties of coefficient of thermal expansion and modulus of rupture are stabilized and controlled by using a combination of two dopants in the glass during sintering and crystallization. There is further disclosed the method of producing such bodies, and controlling such properties, through the use of the two dopants.

Abstract: An improved dielectric formulation for the fabrication of multilayer, integrated circuits which comprises a devitrifying zinc-magnesium-barium-aluminum-zirconium-phosphosilicate glass frit, a devitrifying zinc-magnesium-barium-aluminum-silicate glass frit, or a devitrifying zinc-magnesium-strontium-aluminum-silicate glass frit which are stabilized by the presence of from about 0.01 to about 1 weight percent each of lead oxide and iron oxide.

Abstract: The present invention is directed to a ceramic coated metal substrate having improved processibility characteristics in the manufacture of electronic devices, as for example electronic circuits, and to processes for manufacture of such devices.

Abstract: A porous cordierite ceramic and a process for making the same are provided by the present invention. Preferably, the ceramic material includes at least about 95 percent cordierite in the crystal phase, a porosity of at least about 30 volume percent, a crush load strength of at least about 6 pounds, and a thermal conductivity of less than about 5 watts/meter-.degree.K. The method of producing a porous cordierite ceramic includes (a) combining alumina, clay, talc, a pore-forming material and preferably free silica; (b) adding binder, water and other additives; and (c) shaping the mixture to form a green body. The green body is thereafter fired to form a sintered ceramic body. The porous cordierite is useful in a heat source retainer.

Abstract: The inorganic biomaterial of the present invention comprises a ceramic-crystallized glass composite wherein a zirconia ceramic, an alumina ceramic or a zirconia-alumina ceramic is dispersed in a crystallized glass composed mainly of CaO, P.sub.2 O.sub.5, MgO and Al.sub.2 O.sub.3. This inorganic biomaterial, having biocompatibility and a high strength, is useful as an implant material for artificial bones and dental implants.

Abstract: Ceramic matrix composite articles comprising a ceramic, glass-ceramic or glass matrix and a fiber reinforcement phase disposed within the matrix consisting of amorphous or crystalline inorganic fibers, wherein there is provided, on or in close proximity to the surfaces of the inorganic fibers, a layer of sheet silicate crystals constituting a sheet silicate interface between the inorganic fibers and the ceramic, glass, or glass-ceramic matrix. Optionally, the composition of the matrix may be the same as the sheet silicate interface so that the matrix provides the sheet silicate layer.

Abstract: Ceramic matrix composite articles comprising a ceramic, glass-ceramic or glass matrix and a fiber reinforcement phase disposed within the matrix consisting of amorphous or cyrstalline inorganic fibers, wherein there is provided, on or in close proximity to the surfaces of the inorganic fibers, a layer of sheet silicate crystals constituting a sheet silicate interface between the inorganic fibers and the ceramic, glass, or glass-ceramic matrix. Optionally, the composition of the matrix may be the same as the sheet silicate interface so that the matrix provides the sheet silicate layer.

Abstract: Ceramic matrix composites and a method for making them are provided, the composites comprising a matrix of an alkaline earth aluminosilicate glass or an alkaline earth aluminosilicate glass-ceramic reinforced with inorganic fibers such as silicon carbide fibers, and the matrix being modified by the incorporation therein of an inorganic particulate additive, the additive being present in a proportion at least effective to increase the interlaminar shear strength, transverse flexural strength, and/or fracture toughness of the composites.

Abstract: The present invention provides a method of synthesizing amorphous cordierite-forming glasses from organometallic precursors. Either the sol-gel/.beta.-diketonate technique or the amorphous chelating hydroxycarboxylate process can be used advantageously. The method of the present invention can also be used to form 5 component comprised and 2 component comprised amorphous compositions wherein one of the components is an oxide of silicon.

Abstract: This invention relates to the production of glass-ceramic materials particularly suitable for use as substrates in integrated circuit packaging. The inventive glass-ceramics can be prepared from thermally crystallizable glass capable of being concurrently sintered and crystallized in situ at temperatures between about 850.degree.-1000.degree. C. to bodies exhibiting dielectric constants less than about 6, linear coefficients of thermal expansion between about 12-60.times.10.sup.-7 /.degree.C. and containing cordierite solid solution as essentially the sole crystal phase. The glass-ceramics are essentially free from Li.sub.2 O and Na.sub.2 O and consist essentially, expressed in terms of weight percent on the oxide basis of 10-25% MgO+ZnO consisting of 2-18% MgO+0-21% ZnO, 20-38% Al.sub.2 O.sub.3, 40-52% SiO.sub.2, and 2-15% total of at least one oxide in the indicated proportion selected from the group consisting of up to 8% of an alkali metal oxide selected from the group consisting of K.sub.2 O, Rb.sub.

Abstract: The present invention relates to a cordierite (2MgO.2Al.sub.2 O.sub.3.5SiO.sub.2) type ceramic powder sintering at low-temperature defined in that its composition is: 60 to 50% SiO.sub.2, 5 to 20% MgO and 20 to 40% Al.sub.2 O.sub.3, and in that its specific surface area is not less than 50 m.sup.2 /g, this powder having a fritting temperature of less than 1,100.degree. C.The invention also relates to a process for the preparation of this powder, which consists in preparing a mixed alcoholic solution of an aluminum and silicon salt, in preparing a solution of an alcohol-soluble magnesium salt, in mixing the two solutions, in padding a hydrolyzing agent in the form of a totally volatile weak base to the solution, which leads to the formation of a gel, in subjecting the said gel to a first thermal treatment at a temperature not exceeding 450.degree. C., and in subjecting the said powder to a second thermal treatment at a temperature of between 450.degree. C. and 900.degree. C.

Abstract: New type porous cordierite ceramics having a new characteristic interconnecting open cellular structure and a hollow microspherical cordierite glass powder with a shell devoid of any pores or provided with a few or an abundance of open pores which is used as a starting material for the porous cordierite ceramics. The porous cordierite ceramics are produced by subjecting a starting solution containing an alkyl silicate, an aluminum salt and an magnesium salt optionally with other compounds in an organic or aqueous organic solvent to spray thermal decomposition to prepare the hollow microspherical cordierite glass powder, and then processing the cordierite glass powder to a shaped body after or before an optional heat treatment and firing the shaped body at a temperature below the melting point of cordierite. The porous cordierite ceramics are useful as a carrier for gas chromatography or various chemical reactions.

Abstract: A silicon carbide fiber reinforced glass-ceramic matrix composite article is disclosed. The matrix is a lithium alumino silicate glass-ceramic composition which may include from 1 to 5 weight percent B.sub.2 O.sub.3. The fiber reinforced glass-ceramic matrix composite article exhibits both high flexural strength at elevated temperatures and oxidative stability at elevated temperatures in an oxidizing environment.

Abstract: Ceramic moldings containing finely crystalline cordierite are described, which are obtainable by the intensive grinding of precrystallized cordierite powder, mixing the powder with second additive phases of higher modulus of elasticity, shaping the mixture, and sintering the greenware thus obtained in a siliceous atmosphere at temperatures between 900.degree. and 1400.degree. C. The moldings according to the invention have not only good mechanical strengths but also outstanding dielectric and thermal properties; they are therefore especially suitable for use as dielectrics and as thermal insulating components.

Abstract: Whisker-reinforced ceramic matrix composites comprising a principal crystal phase selected from the group of anorthite, barium-stuffed cordierite, and mixed cordierite/anorthite are prepared by extrusion of extrudable ceramic batches comprising an extrusion vehicle and a solids component consisting essentially of inorganic whiskers and powdered glass, the glass being a thermally crystallizable glass containing an internal nucleant and capable of being consolidated at ambient pressures or above to a dense consolidated preform which may be converted to a substantially glass-free whisker-reinforced ceramic matrix composite by thermal treatment.

Abstract: A Group IIA metal-Group IIIA metal-silicon substantially homogeneous liquid alkoxide is prepared from a reaction mixture of a Group IIA metal, a Group IIIA metal, a silicon tetraalkoxide, and a liquid defined by the formula ROR' where R is an alkyl group and R' is hydrogen or an alkyl group. The alkoxide can then be hydrolyzed, azeotropically distilled, dried, milled, and calcined to produce a ceramic powder. Advantageously, the ceramic powder can be compacted and sintered at relatively low temperatures which enable it to be used in electrical applications where high sintering temperatures would be deleterious.

Abstract: A process for preparing spheroid particles of oxide compounds, having an average diameter of smaller than 3 microns. An emulsion is prepared of a hydrolyzable liquid oxide compound in a perfluoropolyether, the emulsion is reacted with water, water vapor or with a mixture, in any ratio, of water with a liquid miscible or immiscible with water so as to form an oxide hydrate which is recovered dried and calcined. Oxide compounds include oxides of Ti, Al, Zr, Si or B.

Abstract: Micaceous-cordierite-glass ceramic particularly suitable for stomatological, head surgery and neck surgery applicatiosn has a fracture toughness K.sub.IC of up to 2.0 MPa m.sup.1/2, a hardness HV.sub.0.07 of 300-1000, a compressive strength of up to 450 N/mm.sup.2, a linear thermal expansion coefficient of 75-125.times.10.sup.-7 K.sup.-1, good chemical stability and excellent machinability as well as a high resistance to wear and comprises a composition in weight percentages of______________________________________ SiO.sub.2 43-50 Al.sub.2 O.sub.3 26-30 MgO 11-15 R.sub.2 O 7-10.5 F.sup.- 3.3-4.8 Cl.sup.- 0.01-0.6 CaO 0.1-3 P.sub.2 O.sub.5 0.1-5 ______________________________________wherein R.sub.2 O is the sum of 3 to 5.5 wt. % Na.sub.2 O and 4 to 6 wt. % K.sub.2 O, a first crystal phase of mica, and a second crystal phase of 5 to 30 volume % cordierite, wherein relatively large mica crystals of 10 to 200 .mu.m are embedded in the glass and cordierite crystals of 0.5 to 5 .mu.m are arranged in the glass.

Abstract: A mixture of ceramic filler and a matrix forming silicate and/or aluminosilicate material is compressed at a temperature at which the matrix forming material is molten to produce a composite.

Abstract: A composite ceramic extrusion die consisting of a silicon carbide wisker-reinforced cordierite ceramic wherein the predominant matrix phase is cordierite or, preferably, barium-stuffed cordierite having a crystal compositon xBaO.4MgO.(4+x)Al.sub.2 O.sub.3.(10-2x)SiO.sub.2 wherein x ranges from zero up to about 0.5, such extrusion die exhibiting excellent durability under the conditions of non-ferrous metal alloy extrusion at temperatures of 700.degree.-900.degree. C., is described.

Abstract: A sintered glass-powder product of a glass ceramic body, consisting essentially of: SiO.sub.2, Al.sub.2 O.sub.3, MgO, and B.sub.2 O.sub.3, and sintered at a temperature below 900.degree. C. The product includes a microstructure of alpha-cordierite and magnesium aluminum silicate (MgO.Al.sub.2 O.sub.3.4SiO.sub.2) homogeneously dispersed in the glass ceramic body. When the sintered glass-powder product is used in the form of a green sheet for fabricating, in particular, a multilayer wiring substrate or the like, the required sintering temperature for fabricating the substrate can be remarkably reduced so as to be well-matched in thermal characteristics with such wiring conductors as gold, silver, copper, or the like, and even with a relatively large semiconductor chip because the thermal expansion coefficient of the sintered product is close to that of silicon semiconductor.

Abstract: Cordierite series dense and low expansion ceramics have excellent thermal shock resistance property, being airtight, heat resistant and having high dimensional stability at high temperatures can be achieved by incorporating 2-10% by weight of P.sub.2 O.sub.5 in the cordierite ceramic and acid treating the fired or sintered body to selectively remove P.sub.2 O.sub.5 to primarily result in an amount of 0.1% by weight of P.sub.2 O.sub.5 remaining in the sintered body.

Abstract: This invention is directed to the production of glass-ceramic materials especially designed for substrates in integrated circuit packaging. The glass-ceramics can be prepared from thermally crystallizable glasses that can be sintered into an integral glass-ceramic having a dielectric constant less than 6 and containing willemite as the predominant crystal phase. The overall composition of the glass-ceramic consists essentially, in weight percent of 15-45% ZnO, 10-30% Al.sub.2 O.sub.3, and 30-55% SiO.sub.2. Where desired, a nucleating agent selected from the group consisting of 8-12% ZrO.sub.2 and 0.001-0.05% of a noble metal selected from the group consisting of Au, Pd, and Pt may be included.

Abstract: A composite glass ceramic material which comprises silicon nitride (Si.sub.3 N.sub.4) whiskers in a glass ceramic material comprising nitrogen doped cordierite, which composite material has greatly increased strength at elevated temperatures, good microwave transparency, and good thermal shock resistance.The invention further comprises a method for manufacturing the composite material by blending ground nitrogen doped cordierite glass with between about 5 and about 50 percent Si.sub.3 N.sub.4 whiskers by weight of glass. The blend is then formed into a desired shape and is sintered at an elevated temperature of from about 1000.degree. to 1400.degree. C.The invention also includes the novel nitrogen doped cordierite glass and glass ceramic made therefrom.

Abstract: New type porous cordierite ceramics having a new characteristic interconnecting open cellular structure and a hollow microspherical cordierite glass powder with a shell devoid of any pores or provided with a few or an abundance of open pores which is used as a starting material for the porous cordierite ceramics. The porous cordierite ceramics are produced by subjecting a starting solution containing an alkyl silicate, an aluminum salt and an magnesium salt optionally with other compounds in an organic or aqueous organic solvent to spray thermal decomposition to prepare the hollow microspherical cordierite glass powder, and then processing the cordierite glass powder to a shaped body after or before an optional heat treatment and firing the shaped body at a temperature below the melting point of cordierite. The porous cordierite ceramics are useful as a carrier for gas chromatography or various chemical reactions.

Abstract: This invention is concerned with the production of glass-ceramic articles wherein enstatite constitutes the predominant crystal phase. Compositions exhibiting a high modulus of rupture, a use temperature in excess of 1200.degree. C., and a high fracture toughness consist essentially, expressed in terms of weight percent on the oxide basis, of about 20-35% MgO, 2-12% Al.sub.2 O.sub.3, 40-70% SiO.sub.2, and at least one metal oxide in the indicated proportions selected from the group consisting of 0-2% Li.sub.2 O, 0-4% CaO, 0-12% SrO, and 0-17% BaO, at least 0.5% Li.sub.2 O being required when present alone and at least 1% SrO and/or BaO being required in the absence of Li.sub.2 O. Compositions exhibiting a use temperature of 1500.degree. C. consist essentially, expressed in terms of weight percent on the oxide basis, of about 30-35% MgO, 53-58% SiO.sub.2, and 10-14% ZrO.sub.2.

Abstract: A method for producing a multilayer ceramic circuit board including the steps of forming a multilayer structure consisting of patterns of copper-based paste and glass-ceramic layers, the glass-ceramic layers consisting of a mixture of 10 percent to 75 percent by weight of .alpha.-alumina, 20 percent to 60 percent by weight of crystallizable or noncrystallizable glass which can be sintered at a temperature lower than the melting point of copper, and 5 percent to 70 percent by weight of quartz glass, based on the total weight of the glass-ceramic, blended with a binder containing a thermally depolymerizable resin; prefiring the multilayer structure in an inert atmosphere containing water vapor, the partial pressure of which is 0.005 to 0.3 atmosphere, at a temperature where the thermally depolymerizable resin is eliminated; and firing the multilayer structure in an inert atmosphere containing no water vapor at a temperature below the melting point of copper so as to sinter the glass-ceramic.

Abstract: A silicon carbide fiber reinforced barium modified magnesium aluminosilicate matrix composite is described having high strength and thermal stability at temperatures in excess of 1200.degree. C. The matrix material contains about 5% to about 14% magnesium oxide and about 5% to about 25% barium oxide. While any suitable ratios of fiber to matrix can be used, the composite for most applications for example, in the heat engine area, will contain approximately 20% to 50% by volume silicon carbide fibers.

Abstract: A silicon carbide fiber reinforced barium modified magnesium aluminosilicate matrix composite is described having high strength and thermal stability at temperature in excess of 1200.degree. C. The matrix material contains about 5% to about 14% magnesium oxide and about 5% to about 25% barium oxide. While any suitable ratios of fiber to matrix can be used, the composite for most applications for example, in the heat engine area, will contain approximately 20% to 50% by volume silicon carbide fibers.

Abstract: An arc discharge lamp is provided using sealing compositions comprising mainly Al.sub.2 O.sub.3 --SiO.sub.2 --MgO. Preferred compositions include between 25 to 28% by weight of MgO and 13 to 21% by weight of Al.sub.2 O.sub.3 since these have lower melting points than others in the group. Additives of B.sub.2 O.sub.3, nucleating agents and HfO.sub.2 and other rare earth oxides are preferred. The sealing compositions are used to seal end closure members of alumina or CERMET to ceramic arc tubes for use in discharge lamps. The compositions are selected to have linear expansion co-efficients compatible with the materials of the end closures and arc tubes. The methods described give scaling times of between 3 and 4 minutes.

Abstract: Method for producing a polycrystalline body comprised of from about 50% by weight to about 95% by weight of zircon and from about 5% by weight to about 50% by weight of cordierite, said body having a density greater than 85% of its theoretical density.

Abstract: A glass-ceramic product is disclosed. The glass product is produced by combining 0.1 to 6 wt % of a compound selected from the group consisting of B.sub.2 O.sub.3 and P.sub.2 O.sub.5 with a mixture. The mixture includes 54 to 63 wt % SiO.sub.2, 20 to 28 wt % Al.sub.2 O.sub.3, 10 to 18 wt % MgO and 2 to 6 wt % ZnO. From the combined compound and mixture are formed a glassy material and then glassy material is ground in order to form a frit. The frit is then molded and the molded frit is fired into a crystalline form. The resulting glass-ceramic product has a low permittivity as compared with alumina and low power factor tan .delta.. Further, the product has a coefficient of thermal expansion which is comparable with the value for silicon semiconductor chips. The product also has other desirable characteristics such as its firing and crystallizing temperature, moisture absorption and mechanical strength.

Abstract: Method for producing a polycrystalline body comprised of from about 50% by weight to about 95% by weight of mullite and from about 5% by weight to about 50% by weight of cordierite, said body having a porosity of less than about 10% by volume.