Abstract: The glass-ceramic joining material, which is suitable for bonding or joining at low processing temperatures, especially less than 800° C., is composed of a BaO—SiO2—CaO—B2O3—Al2O3 system and has a coefficient of thermal expansion ?(20-300)?9.5·10?6 K?1.

Abstract: A glass ceramic composition that contains a first ceramic including at least one of MgAl2O4 and Mg2SiO4; a second ceramic including BaO, RE2O3 (RE is a rare-earth element), and TiO2; glass containing each of 44.0 to 69.0 weight % of RO (R is an alkaline-earth metal), 14.2 to 30.0 weight % of SiO2, 10.0 to 20.0 weight % of B2O3, 0.5 to 4.0 weight % of Al2O3, 0.3 to 7.5 weight % of Li2O, and 0.1 to 5.5 weight % of MgO; and MnO.

Abstract: A low density material and a method for preparing a low-density material and precursor for forming a low-density material are provided. An aqueous mixture of inorganic primary component and a blowing agent is formed, the mixture is dried and optionally ground to form an expandable precursor. Such a precursor is then fired with activation of the blowing agent being controlled such that it is activated within a predetermined optimal temperature range. The firing conditions are also controlled to provide a low density sphere containing a heterogeneous sphere wall structure comprising a combination of amorphous glass and a crystalline phase or gas phase or both.

Abstract: The various embodiments of the present invention are directed to wear resistant coatings, tiles having the wear resistant coatings disposed thereon, and to methods of making the coatings and tiles. A wear resistant coating generally includes a strontium aluminosilicate glass-ceramic composition that is formed from a glaze. The glaze can include a crystallizing component, which itself can include strontium, aluminum, and silicon, but also comprises less than about 2 weight percent each of lithium, boron, barium, sodium, iron, titanium, zirconium, and carbon, based on a total weight of the crystallizing component.

Abstract: The invention provides a powder comprising at least 95% by number of fused grains, with the following chemical composition, as a percentage by weight based on the oxides, for a total of 100%: 0?BaO?40.8%; 0?SrO?31.8%; 27.2%?Al2O3?31.3%; 32%?SiO2?36.9%; other species ?1%; the quantity of at least one of the oxides BaO and SrO being more than 0.3%, the size of said grains being such that D5?5 ?m and D95?150 ?m.

Abstract: A formation of internally nucleated glass ceramics articles that can be heated in the 1350-1450° C. range for extended periods of time without significant deformation or change in shape is disclosed. The predominant crystal phase of these glass ceramics is celsian (BaAl2Si2O8) or its strontium equivalent (SrAl2Si2O8), or solid solutions or mixtures of these compositions, all belonging to the feldspar mineral group.

Abstract: The transparent polycrystalline optoceramic has single crystallites and at least 95 percent by weight of the single crystallites have a cubic pyrochlore or fluorite structure. The optoceramic is composed of an oxide of stoichiometry: A2+xByDzE7 wherein 0<x<1, 0<y<2, 0<z<1.6 and 3x+4y+5z=8; wherein A is at least one trivalent rare earth cation; B is at least one tetravalent cation; D is at least one pentavalent cation; and E comprises at least one divalent anion. Refractive, diffractive or transmissive optical elements are made with these optoceramics.

Abstract: The invention is directed to highly crystalline, frit-sintered glass-ceramic materials and seals made using them that are suitable for solid oxide fuel cell applications. The seals have a coefficient of thermal expansion in the range of 70-130×10?7° C., preferably 85-115×10?7° C. The glass-ceramic materials have a crystalline component and a glass component, the crystalline component being >50% of the glass-ceramic and the glass component being <50%. In one preferred embodiment the crystalline component is >75%. Regarding the crystalline component only, >50% of the crystals in the crystalline component of the glass-ceramic has a structure selected from the structural groups represented by walstromite, cyclowollastonite, ?-(Ca,Sr)SiO3, kalsilite, kaliophilite and wollastonite (the primary crystalline phase) and the remaining <50% of the crystalline component is at least one secondary crystalline phase.

Abstract: A synthetic microsphere having a low alkali metal oxide content and methods of forming the microsphere and its components are provided. The synthetic microsphere is substantially chemically inert and thus a suitable replacement for natural cenospheres, particularly in caustic environments such as cementitious mixtures. The synthetic microsphere can be made from an agglomerate precursor that includes an aluminosilicate material, such as fly ash, a blowing agent such as sugar, carbon black, and silicon carbide, and a binding agent. The synthetic microsphere is produced when the precursor is fired at a pre-determined temperature profile so as to form either solid or hollow synthetic microspheres depending on the processing conditions and/or components used.

Abstract: A ceramic body, a ceramic catalyst body, a ceramic catalyst body and related manufacturing methods are disclosed wherein a cordierite porous base material has a surface, formed with acicular particles made of a component different from that of cordierite porous base material, which has an increased specific surface area with high resistance to a sintering effect. The ceramic body is manufactured by preparing a slurry containing an acicular particle source material, preparing a porous base material, applying the slurry onto a surface of the porous base material and firing the porous base material, whose surface is coated with the slurry, to cause acicular particles to develop on the surface of the porous base material. A part of or a whole of surfaces of the acicular particles is coated with a constituent element different from that of the acicular particles.

Abstract: A non-lead glass for forming a dielectric, which consists essentially of, as represented by mol %, from 20 to 39% of SiO2, from 5 to 35% of B2O3, from 2 to 15% of Al2O3, from 1 to 25% of CaO+SrO, from 5 to 25% of BaO, from 0 to 35% of ZnO, and from 0 to 10% of TiO2+ZrO2+SnO2, provided that B2O3+ZnO is from 15 to 45%, and which does not contain alkali metal oxides, or contains such oxides in a total amount within a range of less than 1%. Further, a glass ceramic composition for forming a dielectric, which consists essentially of a Ba-containing compound powder and a powder of the above mentioned non-lead glass for forming a dielectric. Further, a dielectric obtained by firing the above glass ceramic composition for forming a dielectric.

Abstract: The invention is directed to highly crystalline, frit-sintered glass-ceramic materials and seals made using them that are suitable for solid oxide fuel cell applications. The seals have a coefficient of thermal expansion in the range of 70-130×10?7° C., preferably 85-115×10?7° C. The glass-ceramic materials have a crystalline component and a glass component, the crystalline component being>50% of the glass-ceramic and the glass component being<50%. In one preferred embodiment the crystalline component is >75%. Regarding the crystalline component only,>50% of the crystals in the crystalline component of the glass-ceramic has a structure selected from the structural groups represented by walstromite, cyclowollastonite, ?-(Ca,Sr)SiO3, kalsilite, kaliophilite and wollastonite (the primary crystalline phase) and the remaining <50% of the crystalline component is at least one secondary crystalline phase.

Abstract: The invention is based on the object of providing armoring that is lightweight and exhibits a denser microstructure that is improved as against ceramic composite materials. To this end, armoring against high dynamic impulsive loads is provided that comprises a composite material having at least two phases, the first phase forming a matrix for the second phase, and the first phase being a glass or a glass ceramic, and the second phase being embedded and distributed in the form of particles and/or fibers in the matrix formed by the material of the first phase.

Abstract: The invention is directed to highly crystalline, frit-sintered glass-ceramic materials and seals made using them that are suitable for solid oxide fuel cell applications. The seals have a coefficient of thermal expansion in the range of 70-130×10?7° C., preferably 85-115×10?7° C. The glass-ceramic materials have a crystalline component and a glass component, the crystalline component being >50% of the glass-ceramic and the glass component being <50%. In one preferred embodiment the crystalline component is >75%. Regarding the crystalline component only, >50% of the crystals in the crystalline component of the glass-ceramic has a structure selected from the structural groups represented by walstromite, cyclowollastonite, ?-(Ca,Sr)SiO3, kalsilite, kaliophilite and wollastonite (the primary crystalline phase) and the remaining <50% of the crystalline component is at least one secondary crystalline phase.

Abstract: Nanoscale particles, particle coatings/particle arrays and corresponding consolidated materials are described based on an ability to vary the composition involving a wide range of metal and/or metalloid elements and corresponding compositions. In particular, metalloid oxides and metal-metalloid compositions are described in the form of improved nanoscale particles and coatings formed from the nanoscale particles. Compositions comprising rare earth metals and dopants/additives with rare earth metals are described. Complex compositions with a range of host compositions and dopants/additives can be formed using the approaches described herein. The particle coating can take the form of particle arrays that range from collections of disbursable primary particles to fused networks of primary particles forming channels that reflect the nanoscale of the primary particles. Suitable materials for optical applications are described along with some optical devices of interest.

Abstract: An opalescent glass-ceramic product, especially for use as a dental material or as an additive to or component of dental material, including SiO2, Al2O3, P2O5, Na2O, K2O, CaO and Me(IV))O2. In order to obtain improved opalescence with improved transparency, in addition to fluorescence, thermal expansion and a combustion temperature adapted to other materials, the opalescent ceramic product is completely or substantially devoid of ZrO2 and TiO2, such that the Me(II)O content in the glass ceramic is less than approximately 4 wt % and the Me(IV)O2 content amounts to approximately 0.5-3 wt %. The invention also relates to a method for the production of the opalescent glass-ceramic product.

Abstract: A high-strength, low-temperature-sintered ceramic composition having a structure comprising a SrAl2Si2O8 crystal and an Al2O3 crystal, the SrAl2Si2O8 crystal being composed of hexagonal SrAl2Si2O8 alone or hexagonal SrAl2Si2O8 and monoclinic SrAl2Si2O8, and a peak intensity ratio represented by I101/(I101+I002)×100 being 5% or more in an X-ray diffraction measurement by a Cu—K? line, wherein I101 represents a peak intensity of a (101) plane of the hexagonal SrAl2Si2O8, and I002 represents a peak intensity of a (002) plane of the monoclinic SrAl2Si2O8.

Abstract: A multilayer ceramic substrate which is obtained by firing multilayers of ceramic green sheets each having a dielectric layer, made of a glass-ceramic material comprising a mixture of alumina and a glass containing at least Si and Ca, and an electrode layer made of Ag and formed on the dielectric layer. The dielectric layer after firing includes anorthite (CaAl2Si2O8) crystals having a grain size of up to 84 nm.

Abstract: The disclosure relates to a leucite glass ceramic doped with nanoscale metal oxide, to a doped leucite glass ceramic powder suitable for its production, to a method for producing the doped leucite glass ceramic, to its use as dental material, to a dental product containing it and to the use of the nanoscale metal oxide powders for the production of the doped glass ceramic or of the doped leucite glass ceramic powder.

Abstract: The invention relates to uses of glasses and glass-ceramics in dental and orthodontic applications.

Abstract: An aluminum titanate-based ceramic body having a composition a formula comprising a(Al2O3.TiO2)+b(CaO.Al2O3.2SiO2)+c(SrO.Al2O3.2SiO2)+d(BaO.Al2O3.2SiO2)+e(3Al2O3.2SiO2)+f(Al2O3)+g (SiO2)+h(Fe2O3.TiO2)+i(MgO.2TiO2), wherein a, b, c, d, e, f, g, h, and i are weight fractions of each component such that (a+b+c+d+e+f+g+h+i)=1, wherein 0.5<a?0.95; 0?b?0.5; 0?c?0.5; 0?d?0.5; 0<e?0.5; 0?f?0.5; 0?g?0.1; 0?h?0.3; 0?i?0.3; b+d>0.01. A method of forming the ceramic body is provided. The ceramic body is useful in automotive emissions control systems, such as diesel exhaust filtration.

Abstract: The object of the present invention is to provide a flat-panel-display substrate which is high in heat resistance, of which the coefficient of thermal expansion is approximated to that of a thick film dielectric layer, which is low at high temperatures in reactivity with the lead-doped thick film dielectric layer, and which can be made to have a large area. The substrate of the present invention is obtained by sintering a body comprising glass powder and a filler made of metal and/or semi-metal oxide, and is constituted by the sintered body and whose average coefficient of linear thermal expansion is from 7 to 9.5 ppm/° C. in the temperature range of 25 to 700° C. The glass powder includes alkaline-earth oxide, 15 to 50% by weight of silicon oxide, and no greater than 2% by weight of boron oxide. Furthermore, the filler is at a concentration of 10 to 30% by volume of the total amount of the glass powder and the filler in the mould.

Abstract: A glass-ceramic composite material for use in forming a multilayered circuit substrate is provided which has a low dielectric constant, but exhibits a relatively high thermal expansion coefficient. Specifically, the glass-ceramic composite material comprises a glass power and a ceramic powder. The glass powder contains: about 30 to 60 mol % of SiO2, about 20 to 40 mol % of BaO, 0 to about 40 mol % of MgO, 0 to about 40 mol % of ZnO, 0 to about 20 mol % of B2O3, with the total content of MgO and ZnO being about 10 to 40 mol %. The ceramic powder contains an alumina powder. The content of the glass powder is set to be at least about 50 wt %. A sintered compact formed by sintering the above glass powder and the above ceramic powder contains a BaO.Al2O3.2SiO2 (BaAl2Si2O8) crystal, and its Q value becomes about 400 or more when a measured frequency is 10 GHz.

Abstract: Nanoscale particles, particle coatings/particle arrays and corresponding consolidated materials are described based on an ability to vary the composition involving a wide range of metal and/or metalloid elements and corresponding compositions. In particular, metalloid oxides and metal-metalloid compositions are described in the form of improved nanoscale particles and coatings formed from the nanoscale particles. Compositions comprising rare earth metals and dopants/additives with rare earth metals are described. Complex compositions with a range of host compositions and dopants/additives can be formed using the approaches described herein. The particle coating can take the form of particle arrays that range from collections of disbursable primary particles to fused networks of primary particles forming channels that reflect the nanoscale of the primary particles. Suitable materials for optical applications are described along with some optical devices of interest.

Abstract: A ceramic material has a thermal expansion coefficient of 50×10−7/° C. or less, an absolute value of the difference between the relative refractive indexes of silica glass and the ceramic material of 0.2 or less at a wavelength of 1550 nm, and a light attenuation coefficient of 0.3 dB/cm or more.

Abstract: A ceramic structure which is pollucite-based and has high refractoriness and high resistance to thermal shock. The inventive structure is suitable in high temperature applications such as a filtering particulates from diesel engine exhaust.

Abstract: A glass ceramic, for use as a resistor or a gas-tight glass ceramic solder for use in a spark plug, includes a fused seal of a starting glass fused from a starting mixture containing SiO2, Al2O3, TiO2 and CaO, the fused seal including crystalline phases in at least some areas. A method for producing such a glass ceramic provides for the starting glass to be processed in a first method step to form a starting material, which is heated for a first period of time in a second method step from a starting temperature, which is below the softening temperature of the starting glass, to a fusion temperature, which is above the softening temperature of the starting glass, and is kept at that temperature for a second period of time and finally is cooled again. A spark plug may include a terminal stud and a center electrode, which are electrically connected across a resistor that is formed in at least some areas by the glass ceramic.

Abstract: In a sintered glass ceramic product including at least three layers each of which is formed by a glass ceramic material, the layers are stacked to be substantially symmetrical in a stacking direction and integrally sintered. Among the sintered layers, each of outermost layers and an inner layer adjacent thereto have crystal phases different from each other. Each of the outermost layers and the inner layer have thermal expansion coefficients &agr;1 and &agr;2 selected so that the relationship given by 0<&agr;2−&agr;1<5 ppm is satisfied.

Abstract: A glass or glass powder is fused from a starting mixture containing approximately 38 wt % to 48 wt % SO2, 15 wt % to 19 wt % Al2O3, 4.5 wt % to 11 wt % TiO2, 0 wt % to 1.5 wt % Na2O, 0 wt % to 1.5 wt % K2O and 23 wt % to 30 wt % CaO. In addition, a glass powder mixture includes two glass powders, a carbon black powder and an organic binder, the first glass powder having a mean particle size of approximately 150 &mgr;m to 250 &mgr;m, the second glass powder having a mean particle size of less than approximately 100 &mgr;m, which may be 10 &mgr;m to 70 &mgr;m. The glass or glass powder mixture is suitable for producing a glass ceramic, such as that used as a resistor seal and/or a gas-tight glass ceramic solder in a spark plug.

Abstract: The present invention provides a low temperature fired porcelain comprising crystalline phases including sanbornite, celsian and &bgr;-cristobalite phases when measured by a high power X-ray diffractometer. The ratio of the peak intensity of (101) plane of &agr;-cristobalite phase to the peak intensity of (101) plane of sanbornite phase is not higher than 5%. The porcelain is of a low temperature fired porcelain of silica-alumina-barium oxide system with cristobalite phase precipitated, in which the incidence of cracks in the porcelain may be reduced.

Abstract: A glass-ceramic has a hexacelsian as a primary crystal phase and is characterized by satisfying a relation of 0≦I(101)/I(110)≦1.5 when a diffraction intensity of (101) face of hexacelsian in an X-ray diffraction is I(101) and a diffraction intensity of (110) face thereof is I(110).

Abstract: Disclosed is a glass ceramic sintered product which contains as crystal phases: (i) a gahnite crystal phase; (ii) a celsian crystal phase containing needle-like crystals having an aspect ratio of not smaller than 3; and (iii) at least one kind of crystal phase selected from the group consisting of AlN, Si3N4, SiC, Al2O3, ZrO2, 3Al2O3.2SiO2 and Mg2SiO4; and has an open porosity of not larger than 0.3%. The glass ceramic sintered product is highly strong, has a high heat conductivity, a high Young's modulus, is dense, and can be produced through the firing at a low temperature of not higher than 1000° C., and is very useful as an insulating substrate that has wiring layers of a low-resistance conductor such as Cu, Ag or Au on the surface thereof or in the inside thereof.

Abstract: Enclosed are crystallized glasses suitable for a substrate for an information recording medium such as a magnetic disc, optical disc, or optomagnetic disc, a substrate for information recording medium using such a crystallized glass substrate, and an information recording medium using such a substrate for information recording medium. The crystallized glasses are capable of providing a glass substrate having a high Young's modulus, as well as excellent mechanical strength, surface flatness, and heat resistance and having an excellent surface smoothness upon polishing. Glass substrate having an excellent surface smoothness using such a crystallized glass are also disclosed.

Abstract: Compositions for use as thermal insulation or barriers in articles that are required to function under transient elevated temperature conditions, such as are experienced during a fire. Articles in which compositions according to the invention may be used include electrical and optical cables which have fire resistant properties, electrical fittings such as terminals and cable clips, and void-filling compounds which are required to act as fire barriers. The invention provides a composition that is ductile or flexible at the elevated temperatures experienced during a fire and retains integrity so as to stay in place throughout the fire enabling it to continue to function as a thermal barrier.

Abstract: Lithium ion conductive glass-ceramics comprise in mol %: P2O5 30-45% SiO2 0-15% GeO2 + TiO2 25-50% in which GeO2 0-50% TiO2 0-50% ZrO2 0-8% M2O3 0<-10% where M is an element or elements selected from the group consisting of In, Fe, Cr, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb and Lu Al2O3 0-12% Ga2O3 0-12% Li2O 10-25% and contain Li1+X(M, Al, Ga)X(Ge1−YTiY)2−X(PO4)3 (where 0<X≦0.8 and 0≦Y≦1.0) as a predominant crystal phase. A solid electrolyte, an electric cell and a gas sensor utilizing these glass-ceramics are also provided.

Abstract: An insulator composition which can be sintered at a relatively low temperature and which exhibits a low dielectric constant and a thermal expansion coefficient suitable for forming an insulator layer of a laminated electronic part contains a crystallized glass composition containing SiO2, MgO and CaO as main components, and Al2O3, an amorphous silicate glass composition, and a ceramic composition. The composition ratio by weight % (SiO2, MgO, CaO) of the main components of the crystallized glass composition lies in a region surrounded by point A (30, 25, 45), point B (30, 5, 65), point C (45, 5, 50) and point D (45, 25, 30) shown in a ternary composition diagram thereof. The thermal expansion coefficient of the insulator composition after sintering can easily be changed by changing the content ratio of the crystallized glass composition, the amorphous silicate glass composition and the ceramic composition.

Abstract: A barrier layer for a silicon containing substrate comprises an alkaline earth aluminosilcate and an additive component capable of forming a reaction product with silica.

Abstract: A glass having an oxide-converted composition of 35 to 65 wt % of SiO2, 5 to 35 wt % of B2O3, 2 to 20 wt % of CaO, 5 to 25 wt % of Al2O3 where the ratio of CaO to Al2O3 is 1/1 to 1/2.5, 0.5 to 5 wt % of TiO2, 0.5 to 5 wt % of ZrO2, 0.5 to 5 wt % of ZnO, 0 to 5 wt % of MgO, 0 to 5 wt % of SrO, 0 to 5 wt % of BaO and 0 to 1 wt % of the total of group 1A element oxides such as Na2O, K2O and Li2O, or a glass having an oxide-converted composition of 10 to 45 wt % of SiO2, 20 to 50 wt % of CaO, 20 to 45 wt % of Al2O3, 0.1 to 5 wt % of MgO, 0.1 to 5 wt % of SrO, 0.1 to 5 wt % of BaO, 0.1 to 5 wt % of TiO2, 0.1 to 5 wt % of ZnO, 0.1 to 5 wt % of ZrO2 and 0 to 3 wt % of a group 1A element oxide has a low glass softening point, can be calcined as a composite with a variety of ceramics at a temperature below 1000° C., precipitates crystals during the calcination process, and can provide a glass ceramic exhibiting a low dielectric constant and a low dielectric loss.

Abstract: A glass-ceramic has a hexacelsian as a primary crystal phase and is characterized by satisfying a relation of 0≦I(101)/I(110)≦1.5 when a diffraction intensity of (101) face of hexacelsian in an X-ray diffraction is I(101) and a diffraction intensity of (110) face thereof is I(110).

Abstract: Enclosed are crystallized glasses suitable for a substrate for an information recording medium such as a magnetic disc, optical disc, or optomagnetic disc, a substrate for information recording medium using such a crystallized glass substrate, and an information recording medium using such a substrate for information recording medium. The crystallized glasses are capable of providing a glass substrate having a high Young's modulus, as well as excellent mechanical strength, surface flatness, and heat resistance and having an excellent surface smoothness upon polishing. Glass substrate having an excellent surface smoothness using such a crystallized glass are also disclosed.

Abstract: Provided is an electrically conductive paste adapted to be sintered at the same time when a ceramic body is being sintered, wherein said paste has a contraction starting temperature that is higher than the contraction ending temperature of said ceramic body during the sintering treatment. Also provided is an electrically conductive paste comprising an electrically conductive component and an organic vehicle component, wherein said electrically conductive component comprises an electrically conductive powder mainly comprising silver, the particles of said electrically conductive powder being coated with a metal oxide having a melting point higher than that of silver.

Abstract: A composition and method of fabricating pressureless sintered 70 volume % silicon nitride-30 volume % barium aluminum silicate ceramic composites. The composites are made from 70 volume % silicon nitride, containing varying amounts and size distributions of initial &bgr;-silicon nitride, and 30 volume % barium aluminum silicate. The resulting ceramic composites contain microstructures with coarse &bgr;-silicon nitride whiskers, as well as narrow distributions of short &bgr;-silicon nitride whiskers, surrounded by fine barium aluminum silicate grains. The resulting composites exhibit improved fracture toughness and flexural strength.

Abstract: A low-fire, low-dielectric ceramic composition is disclosed. The ceramic composition comprises a mixture of finely divided particles consisting of 30-90% by volume of Ca—Ba—Al—Zn—Si glass and 70-10% by volume of oxides, which can be densified up to 95% at temperatures of 800-1000° C. The sintered body produced thereby exhibits a dielectric constant in the range of 6-10 and a dielectric loss in the range of 0.01%-0.5% at 1 MHz. The ceramic composition can be processed with organic solvent, polymeric binder and plasticizer to produce a green sheet which is co-firable with high electrical conductivity metal such as gold, silver, silver-palladium and copper.

Abstract: Multiphase ceramic materials for use in multilayered device fabrication may be fabricated by providing novel glassy precursor materials of a preferred composition, with operable amounts of a non-glassy filler materials. The combined materials are fired at appropriate temperatures, so that a non-glassy anorthite type phase is formed. Material so fabricated is formed in a self-limiting process, in that reaction between the glassy precursor material and the non-glass filler material is terminated when one constituent of the glassy precursor material is fully consumed. The materials of the instant invention, fabricated according to the method disclosed herein, demonstrate excellent dielectric constant, and electrical loss characteristics.

Abstract: Nanocrystalline glass-ceramic materials based on .beta.-quartz solid solution Mg-rich phases formed in the system SiO.sub.2 --Al.sub.2 O.sub.3 --MgO--Li.sub.2 O--TiO.sub.2 (ZnO, BaO, ZrO.sub.2, P.sub.2 O.sub.5). Articles made from the glass-ceramic materials exhibit a crystal phase assemblage of a fine-grained, microstructure which is predominantly .beta.-quartz, and at least one additional phase selected from enstatite and spinel, and having a composition which consists essentially of, in weight percent on the oxide basis, 40-65% SiO.sub.2, 10-14% Al.sub.2 O.sub.3, 5-25% MgO, 0.5-4% Li.sub.2 O, 5-15% TiO.sub.2, and up to 5% ZrO.sub.2, such that the sum of (TiO.sub.2 +ZrO.sub.2) is at least 9% The glass-ceramide article is particularly useful for memory disk applications.

Abstract: A dielectric material is disclosed which has a small absolute value of the temperature coefficient of resonance frequency and a high coefficient of unloaded quality. Also disclosed are a process for producing the dielectric material and multilayer and other circuit boards containing the dielectric material. The dielectric material is a highly densified material having a water absorption lower than 0.1%, which is obtained by mixing 95.5 to 99.5 percent by weight mixture of a glass frit and a strontium compound with 0.5 to 4.5 percent by weight titanium dioxide, compacting the resultant mixture, and sintering the compact at a relatively low temperature around 930.degree. C. This dielectric material is a glass ceramic containing strontium anorthite (SrAl.sub.2 Si.sub.2 O.sub.8) as the main crystalline phase, and may contain the TiO.sub.2, which remains unchanged after sintering. The absolute value of the temperature coefficient of resonance frequency of the dielectric material is 20 ppm/.degree. C.

Abstract: The invention relates to a glass ceramic in which mica and ZrO.sub.2 are present in crystallized form, containing:K.sub.2 O: 0-9% by weightNa.sub.2 O: 0-9% by weight with the condition that Na.sub.2 O and K.sub.2 O together make up at least about 4% by weight,SiO.sub.2 : 35-60% by weightMgO: 10-25% by weightAl.sub.2 O.sub.3 : 7-30% by weightZrO2: 4-12% by weightF.sup.- : 2-10% by weight which is essentially free of lithium, calcium, strontium and barium, to a process for its production and to its use as a tooth replacement.

Abstract: Composite material comprising a CAS+BAS vitroceramic matrix reinforced with SiC fibers and exhibiting a small difference between the thermal expansion coefficients of the matrix and the fibers is obtained by using a matrix having a BaO/(BaO+CaO) molar ratio of between 25% and 55% and predominant phases of triclinic anorthite and monoclinic celsian.

Abstract: Disclosed is use of a vitreous inorganic fiber in the knowledge that it has a composition meeting the criterion that the calculated sum of the free energies of hydration of the compounds that would or could be present at equilibrium (on the basis of knowledge, informed belief or reasonable assumption) is more negative than -10 kcal/100 grams of composition. Such compositions are saline soluble.

Abstract: The glass-ceramic material of the present invention has the hexagonal sheet structure of hexacelsian as its primary crystal phase and exhibits x-ray diffraction patterns indicative of hexacelsian, said glass-ceramic material has a stabilized thermal expansion and an overall weight percent composition comprising: 35-55% SiO.sub.2, 5-25% Al.sub.2 O.sub.3, 5-25% MgO, 5-35% BaO, 6-14% TiO.sub.2, 0-10% ZnO, and 0-8% ZrO.sub.2.