Abstract: Provided is a boehmite structure including a plurality of boehmite particles where adjacent boehmite particles are bonded to each other. In the boehmite structure, a boehmite crystallite size is 10 nm or less, and a porosity is 15% or less. Also provided is a method for producing the boehmite structure, including a mixing step of obtaining a mixture by mixing mechanochemically treated hydraulic alumina with a solvent including water, and a pressure heating step of pressurizing and heating the mixture under a condition of a pressure of 10 to 600 MPa and a temperature of 50 to 300° C.

Abstract: Provided is an inorganic structure including a plurality of inorganic particles; and a binding part that covers a surface of each of the plurality of inorganic particles and binds each of the plurality of inorganic particles together. The binding part contains: an amorphous compound containing at least one of aluminum or titanium, oxygen, and one or more metallic elements; and a plurality of fine particles having an average particle size of 100 nm or less. The plurality of inorganic particles has an average particle size of 1 ?m or more, and the plurality of inorganic particles has a volume percentage of 30% or more.

Abstract: Provided is an inorganic structure including a plurality of zirconium silicate particles; and a binding part that covers a surface of each of the zirconium silicate particles and binds the zirconium silicate particles together. The binding part contains an amorphous compound containing silicon, a metallic element other than silicon, and oxygen, and contains substantially no alkali metal, B, V, Te, P, Bi, Pb and Zn. Also provided is a method for producing an inorganic structure including: a step for obtaining a mixture by mixing a plurality of zirconium silicate particles, a plurality of amorphous silicon dioxide particles, and an aqueous solution containing a metallic element other than silicon; and a step for pressurizing and heating the mixture under conditions of a pressure of 10 to 600 MPa and a temperature of 50 to 300° C.

Abstract: Provided is an inorganic structure including a plurality of magnesium oxide particles; and a binding part that covers a surface of each of the magnesium oxide particles and binds the magnesium oxide particles together. The binding part contains an amorphous compound containing silicon, a metallic element other than silicon, and oxygen, and contains substantially no alkali metal, B, V, Te, P, Bi, Pb, and Zn. Also provided is a method for producing an inorganic structure including: a step for obtaining a mixture by mixing a plurality of magnesium oxide particles, a plurality of amorphous silicon dioxide particles, and an aqueous solution containing a metallic element other than silicon; and a step for pressurizing and heating the mixture under conditions of a pressure of 10 to 600 MPa and a temperature of 50 to 300° C.

Abstract: Provided is an inorganic structure including a plurality of inorganic particles; and a binding part that covers a surface of each of the inorganic particles and binds the inorganic particles together, wherein the binding part contains: an amorphous compound containing silicon, oxygen, and one or more metallic elements; and fine particles having an average particle size of 100 nm or less. Also provided is a method for producing an inorganic structure including: a step for obtaining a mixture by mixing a plurality of inorganic particles, a plurality of amorphous silicon dioxide particles, and an aqueous solution containing a metallic element; and a step for pressurizing and heating the mixture under conditions of a pressure of 10 to 600 MPa and a temperature of 50 to 300° C.

Abstract: Provided is a barium compound structure including: a plurality of first compound particles containing a barium compound that is crystalline and is different from barium sulfate; a binding part covering a surface of each of the plurality of first compound particles and containing barium sulfate that is crystalline; and a plurality of second compound particles containing a compound that contains silicon. The first compound particles are bound through at least one of the binding part or the plurality of second compound particles.

Abstract: Provided is an aluminum nitride structure that includes a plurality of aluminum nitride particles, wherein aluminum nitride particles that are adjacent are bound to each other through a boehmite phase containing boehmite, and the porosity is 30% or less. Also provided is a method for producing an aluminum nitride structure that includes: obtaining a mixture by mixing an aluminum nitride powder with a solvent containing water; and pressurizing and heating the mixture under conditions of a pressure of 10 to 600 MPa and a temperature of 50 to 300° C.

Abstract: A glass structure includes: a plurality of glass particles, each of the glass particles including SiO2, CaO and P2O5; and a bonding portion that bonds the glass particles to one another and contains hydroxyapatite, wherein at least a part of the hydroxyapatite is crystalline in the bonding portion, and wherein a porosity of the glass structure is 15% or less. A method for producing the glass structure includes: preparing a mixture by mixing a plurality of glass particles and an aqueous solution with each other, each of the glass particles including SiO2, CaO and P2O5, and the aqueous solution including calcium and phosphorus and having pH of 4.0 or more; and heating and pressurizing the mixture.

Abstract: A zirconia based ceramic material having improved and well-balanced mechanical strength and toughness consists essentially of 0.5 to 50 vol % of Al.sub.2 O.sub.3 having an average grain size of 2 .mu.m or less and the balance of a partially stabilized zirconia having an average grain size of 5 .mu.m or less. The partially stabilized zirconia consists essentially of 8 to 12 mol % of CeO.sub.2, 0.05 to 4 mol % of TiO.sub.2 and the balance of ZrO.sub.2. Fine Al.sub.2 O.sub.3 grains having an average grain size of 1 .mu.m or less are dispersed within the grains of the partially stabilized zirconia at a dispersion ratio. The dispersion ratio is defined as a ratio of the number of Al.sub.2 O.sub.3 grains dispersed within the grains of the partially stabilized zirconia relative to the number of the entire Al.sub.2 O.sub.3 grains dispersed in the ceramic material, and at least 2% in the present invention. The ceramic material can be made by the following process.

Abstract: A ZrO.sub.2 based ceramic material having excellent mechanical strength and fracture toughness comprises a first phase of ZrO.sub.2 grains containing CeO.sub.2 as a stabilizer and having an average grain size of 5 .mu.m or less, a second phase of Al.sub.2 O.sub.3 grains having an average grain size of 2 .mu.m or less, and a third phase of elongated crystals of a complex oxide of Al, Ce, and one of Mg and Ca. At least 90 vol % of the first phase is composed of tetragonal ZrO.sub.2. An aluminum (Al) content in the ceramic material is determined such that when Al of the complex oxide is converted to Al.sub.2 O.sub.3, a total amount of Al.sub.2 O.sub.3 in the ceramic material is within a range of 0.5 to 50 vol %. A content of the third phase in the ceramic material is determined within a range of 0.5 to 5 by area %. It is preferred that fine Al.sub.2 O.sub.3 grains having an average grain size of 1 .mu.m or less of the second phase are dispersed within the ZrO.sub.2 grains at a dispersion ratio of at least 2%.

Abstract: A zirconia based ceramic material having improved and well-balanced mechanical strength and toughness consists essentially of 0.5 to 50 vol % of Al.sub.2 O.sub.3 having an average grain size of 2 .mu.m or less and the balance of a partially stabilized zirconia having an average grain size of 5 .mu.m or less. The partially stabilized zirconia consists essentially of 8 to 12 mol % of CeO.sub.2, 0.05 to 4 mol % of TiO.sub.2 and the balance of ZrO.sub.2. Fine Al.sub.2 O.sub.3 grains having an average grain size of 1 .mu.m or less are dispersed within the grains of the partially stabilized zirconia at a dispersion ratio. The dispersion ratio is defined as a ratio of the number of Al.sub.2 O.sub.3 grains dispersed within the grains of the partially stabilized zirconia relative to the number of the entire Al.sub.2 O.sub.3 grains dispersed in the ceramic material, and at least 2% in the present invention. The ceramic material can be made by the following process.

Abstract: A zirconia based composite material with improved strength and toughness includes a partially stabilized zirconia including 1.5 to 4.5 mol % of yttrium oxide as a matrix thereof and a metal phase of at least one metal selected from the group consisting of titanium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten as metal grains dispersed in the matrix. The metal phase has a melting point higher than a sintering temperature of the partially stabilized zirconia. In addition, it is preferred that the composite material further contains a ceramic phase of at least one ceramic selected from the group consisting of Al.sub.2 O.sub.3, SiC, Si.sub.3 N.sub.4, B.sub.4 C, carbides, nitrides and borides of titanium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten as ceramic grains dispersed in the matrix. The composite material of the present invention is manufactured by the following steps.

Abstract: A sintered ceramic-metal composite product has a ceramic matrix of polycrystalline ceramic in which a metal phase is dispersed for adding improved toughness. The metal phase has a higher melting point than the sintering temperature of the ceramic matrix and comprises at least one metal selected from the groups IVa, Va and VIa of the periodic table. The metal phase is dispersed intragranular within the grains of the ceramic matrix to realize nano-order dispersion of the metal phase which is responsible for remarkably improved toughness as well as strength. The ceramic-metal composite product is successfully fabricated by several unique methods utilizing the mixture of the ceramic and metal or metal oxide, hydride or alkoxide.

Abstract: A sintered ceramic-metal composite product has a ceramic matrix of polycrystalline ceramic in which a metal phase is dispersed for adding improved toughness. The metal phase has a higher melting point than the sintering temperature of the ceramic matrix and comprises at least one metal selected from the groups IVa, Va and VIa of the periodic table. The metal phase is dispersed intragranular within the grains of the ceramic matrix to realize nano-order dispersion of the metal phase which is responsible for remarkably improved toughness as well as strength. The ceramic-metal composite product is successfully fabricated by several unique methods utilizing the mixture of the ceramic and metal or metal oxide, hydride or alkoxide.