Abstract: A transparent, semitransparent or opaline glass-ceramics containing calcium phosphate crystals uniform and very fine in grain size is obtained by heat-treating a glass essentially comosed of 38-52 wt % of SiO.sub.2, 4-16 wt % of P.sub.2 O.sub.5, 6-18 wt % of Al.sub.2 O.sub.3 (may partly be replaced by La.sub.2 O.sub.3), 20-33 wt % of CaO (may partly be replaced by MgO, BaO,SrO and/or ZnO), 4-17 wt % of ZrO.sub.2 (may partly be replaced by TiO.sub.2) and 0-0.5 wt % of alkali metal oxide(s), wherein the molar ratio of P hd 2O.sub.5 to ZrO.sub.2 is not greater than 3:1, at a temperature above the transition temperature and below the softening temperature of the glass. This glass-ceramics is excellent in refractoriness, electrical insulation resistance, chemical resistance and mechanical strength and has a relatively high coefficient of thermal expansion.

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: 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: The present invention is directed to the production of SiC whisker- and/or fiber-reinforced, internally-nucleated glass-ceramic matrix composite articles consisting essentially of 0.5-60% by weight SiC whiskers and/or 15-70% by volume ceramic fibers substantially uniformly distributed in a glass-ceramic matrix consisting essentially, in weight percent on the oxide basis, of 16-20%, CaO, 38.5-46% Al.sub.2 O.sub.3, 35-42% SiO.sub.2, and up to 10% total of at least one nucleating agent in the indicated proportion selected from the group consisting of 0.1-3% Cr.sub.2 O.sub.3, 0.25-3% HfO.sub.2, 2-5% MoO.sub.3, 0.25-3% Nb.sub.2 O.sub.5, 0.25-3% Ta.sub.2 O.sub.5, 0.25-3% WO.sub.3, and 1-10% ZrO.sub.2, wherein Al.sub.2 O.sub.3 is present in an amount which is at least 5 mole percent and up to 50 mole percent in excess of that present in stoichiometric triclinic anorthite, and wherein the predominant crystal phases in the glass-ceramic are triclinic anorthite and mullite and/or .alpha.-Al.sub.2 O.sub.3. Up to 1.

Abstract: A multicolor liquid crystal display panel including a first and a second transparent substrate sheet of glass, a color filter layer which forms a multiplicity of picture elements and which is interposed between the first and second sheets of glass, an electrode layer having picture-element electrodes corresponding to the picture elements, and a liquid crystal layer whose transmittance of light is locally varied by application of an electric field thereto through the picture-element electrodes. At least one of the first and second sheets of glass is formed of transparent glass ceramics or crystallized glass having a major crystalline phase which consists of crystals of a Li.sub.2 O-Al.sub.2 O.sub.3 -SiO.sub.2 system.

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: The present invention is concerned with the preparation of glass microfoams and gas-ceramics having compositions selected from the systems of SiO.sub.2 --Al.sub.2 O.sub.3 --B.sub.2 O.sub.3 --RO--R.sub.2 O, SiO.sub.2 --Al.sub.2 O.sub.3 (B.sub.2 O.sub.3)--P.sub.2 O.sub.5 --Li.sub.2 O--[ZrO.sub.2 (TiO.sub.2)], and SiO.sub.2 --P.sub.2 O.sub.5 --B.sub.2 O.sub.3 --[RO], wherein RO is selected from the group of MgO, CaO, SrO, BaO, and ZnO, and R.sub.2 O is selected from the group of alkali metal oxides. The foams comprise hydrogen-containing cells produced through the inclusion in the batch of a hydrogen-generating agent selected from the group of ammonium salts and/or a combination of amines and/or carbohydrates and/or hydrocarbons with phosphates.

Abstract: A high-strength glass-ceramic containing apatite crystals or .beta.-tricalcium phosphate crystals, and anorthite crystals, and a process for producing the same are disclosed. The glass-ceramic has an excellent biocompatibility and is useful as an implant material such as an artificial dental root and an artificial bone.

Abstract: Low temperature fired ceramics produced by firing at a low temperature a mixture consisting of, in weight percentages:(a) 50 to 65% of powder glass consisting of 10 to 55% of CaO, 45 to 70% of SiO.sub.2, 0 to 30% of Al.sub.2 O.sub.3 and up to 10% of impurities; and(b) 50 to 35% of powder Al.sub.2 O.sub.3 containing up to 10% of impurities. The glass component (a) may further contains B.sub.2 O.sub.3 up to 20% based on the total weight of the former glass-forming components. The ceramics exhibit excellent thermal conductivity, high mechanical strength, low thermal expansion and small dielectric constant and such advantageous combination of properties make them useful in many applications, more especially highly suited to the use as substrate of various electronic parts, components or multilayer integrated circuits. Also, since the ceramics can be prepared at lower firing temperatures and a higher heating rate, the production cost and time can be advantageously saved.

Abstract: The present invention is directed to SiC whisker and/or fiber reinforced glass-ceramic matrix composite articles wherein an alkaline earth aluminosilicate constitutes the predominant crystal phase. More particularly the composite articles will consist essentially of 10-60% by weight SiC whiskers and/or 15-70% by volume ceramic fibers and the glass-ceramic matrix will consist essentially, by weight on the oxide basis, of______________________________________ CaO 0-25 MgO 0-15 SrO 0-30 Na.sub.2 O 0-4 CaO + SrO 10-30 K.sub.2 O 0-6 Al.sub.2 O.sub.3 25-38 TiO.sub.2 0-12 SiO.sub.2 35-60 ZrO.sub.2 0-15 BaO 0-25 As.sub.2 O.sub.3 0-3 BaO + MgO + Na.sub.2 O + K.sub.2 O + TiO.sub.2 ZrO.sub.2 + As.sub.2 O.sub.3 0-30 ______________________________________The preferred predominant crystal phase is selected from the group of anorthite and its pseudo-binaries, with mullite, cordierite, barium osumilite, and albite solid solution.

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: This invention is concerned with the preparation of thermally crystallizable enamels suitable for application to glass-ceramics, particularly glass-ceramics having coefficients of thermal expansion less than 15.times.10.sup.-7 /.degree.C. The enamels are capable of being fired to maturity simultaneously with the precursor glass body being crystallized to a glass-ceramic. The enamels consist essentially, expressed in weight percent on the oxide basis, of:SiO.sub.2 : 36-58Al.sub.2 O.sub.3 : 8.5-16CaO: 0.5-10PbO: 27-40K.sub.2 O: 0.

Abstract: This invention is directed to the production of glass-ceramic bodies exhibiting high strength and capable of being used at temperatures of 1300.degree. C. and higher. Barium osumilite constitutes the predominant crystal phase and the inventive bodies have overall compositions consisting essentially, in weight percent, of:______________________________________ SiO.sub.2 51-68 Al.sub.2 O.sub.3 17.5-30 MgO 5-12 BaO 3.5-15 Si 0-1 Nb.sub.2 O.sub.5 0-20 Ta.sub.2 O.sub.5 0-10 TiO.sub.2 0-12 ZrO.sub.2 0-6 ______________________________________The bodies can be utilized in monolith form and are very useful as matrices for fiber reinforced structures suitable for high temperature applications.

Abstract: Discontinuous silicon carbide fiber reinforced ceramic composites are disclosed having high strength, fracture toughness, and oxidative stability, even in high temperature oxidative environments. Disclosed composites include silicon carbide fiber reinforced aluminosilicate, lithium aluminosilicate, barium aluminosilicate, magnesium aluminosilicate, and combinations thereof. Flexural strengths in excess of 20,000 psi (138 MPa) at temperatures in excess of 1000.degree. C. are attainable with such composites. The composite is formed by starting with the ceramic matrix material in the glassy state and converting it from the glassy state to the ceramic state after densification of the composite.

Abstract: The instant invention is concerned with the preparation of glass-ceramic coatings capable of being fired repeatedly to temperatures in excess of 950.degree. C. without thermal deformation and being particularly suitable for application to low carbon and titanium-stabilized stainless steels. The coatings are substantially free from alkali metal oxides and consist essentially, expressed in terms of weight percent on the oxide basis, of:______________________________________ BaO 10-60 B.sub.2 O.sub.3 5-30 SiO.sub.2 25-40 Al.sub.2 O.sub.3 0-15 CaO 0-15 MgO 10-35 ZnO 0-16 Al.sub.2 O.sub.

Abstract: The present invention is directed to the production of glass and glass-ceramic compositions which have particular utility as culinary utensils inasmuch as they are exceptionally easy to clean after food has been burned thereon. The products have at least an integral surface layer which contains MgO-based and/or CaO-based and/or SrO-based and/or BaO-based crystals as the predominant crystal phase. Operable compositions consist essentially, expressed in weight percent on the oxide basis, of 14.8-19.6% MgO, 16.2-20.0% Al.sub.2 O.sub.3, and 58.7-66.5% SiO.sub.2, when said surface layer contains MgO-based crystals as the predominant crystal phase, 22.2-31.6% CaO, 42.8-53.9% Al.sub.2 O.sub.3, and 23.8-33.6% SiO.sub.2, when said surface layer contains CaO-based crystals as the predominant crystal phase, 31-48% SrO, 24-35.7% Al.sub.2 O.sub.3, and 28-35% SiO.sub.2, when said surface layer contains SrO-based crystals as the predominant crystal phase, and 42.4-45% BaO, 10-15.9% Al.sub.2 O.sub.3, and 41.7-45% SiO.sub.

Abstract: The present invention is directed to the production of glass-ceramic coatings capable of being fired repeatedly to temperatures in excess of 950.degree. C. without thermal deformation and being especially suitable for application to titanium-stabilized stainless steels. The coatings are highly crystalline, substantially free from alkali metal oxides, and consist essentially, by weight, of:______________________________________ MgO 5-35 CaO 0-35 ZnO 0-25 CaO + ZnO 10-35 Al.sub.2 O.sub.3 0-10 B.sub.2 O.sub.3 0-25 P.sub.2 O.sub.5 0-10 B.sub.2 O.sub.3 + P.sub.2 O.sub.5 4-25 SiO.sub.