The present invention relates to a process for producing a foam ceramic comprising the steps: producing an aqueous suspension of a first mineral raw material; foaming the suspension with air while adding a foaming agent and a binder to form a light foam; mixing the light foam with a powder or slip of a second ceramic raw material to form a heavy foam; pouring the heavy foam into a mold; drying the molded heavy foam in the mold to form a solid foam; and firing the solid foam in the mold to form the foam ceramic.

Provided is a zirconia sintered body that suppresses discoloration due to porcelain. The zirconia sintered body comprises at least one of a coloring agent A: erbium oxide and a coloring agent B: nickel oxide, and a composite oxide of zirconium and vanadium.

A method for producing a counter-form (20) for manufacturing a part having a complex shape (24) by pressure sintering densification. The counter-form (20) is formed from successive layers produced by numerically-controlled three-dimensional (3D) additive printing according to the following steps: numerically recording a three-dimensional negative of the part to be produced (24) in a control unit of a three-dimensional additive printing system in order to constitute the positive form of the counter-form to be produced; producing the counter-form (20) using a 3D additive printing technique. The part having a complex shape (24d) is then manufactured by pressure sintering, then separated from the counter-form which is also sintered (20).

This invention relates to a method for manufacturing a part of complex shape (3) by successive deposition of layers according to a technique of 3D additive printing and pressure sintering, comprising the following steps: an initial step of producing a model (1) from a material chosen from a porous or pulverulent material based on a metal alloy, a ceramic, a composite material and a lost material by formation of successive layers deposited according to the digitally controlled 3D additive printing technique, followed by a step of introducing a preform (1) made of porous or pulverulent material to be densified, derived from the model (1), into a mold (2) filled with a sacrificial porous or pulverulent material (13) in addition to the preform (1), the uniaxial densifying pressure sintering (10) then being applied to the mold (2) in order to form the part (3) which is finally extracted from the mold (2).

A method for preparing an infrared radiation ceramic material includes mixing and ball milling raw materials of Fe.sub.2O.sub.3, MnO.sub.2 and CuO in a mass ratio to obtain a mixed powder; pressing the mixed powder; adjusting laser spot, laser power and laser sintering time of a laser; irradiating or sintering by a first laser the pressed mixed powder in a crucible for a high-temperature solid-phase reaction to obtain an AB.sub.2O.sub.4 type ferrite powder; obtaining a first mixture by mixing the AB.sub.2O.sub.4 type ferrite powder and a cordierite powder in a mass ratio; adding a sintering aid and a nucleating agent for ball milling; obtaining a second mixture by mixing the first mixture and a binder for aging; pressing the second mixture; and irradiating or sintering the pressed second mixture by a second laser to obtain the infrared radiation ceramic material.

A semiconductor ceramic composition represented by formula (1),

(Ba.sub.vBi.sub.xA.sub.yRE.sub.w).sub.m(Ti.sub.uTM.sub.z)O.sub.3  (1),

wherein, A represents at least one element selected from Na and K, RE represents at least one element selected from Y, La, Ce, Pr, Nd, Sm, Gd, Dy and Er;

0.750y≦x≦1.50y  (2),

0.007≦y≦0.125  (3),

0≦(w+z)≦0.010  (4),

v+x+y+w=1  (5),

u+z=1  (6),

0.950≦m≦1.050  (7),

0.001 to 0.055 mol of Ca is contained, and 0.0005 to 0.005 mol of at least one selected from Mg, Al, Fe, Co, Cu and Zn is contained.

A ferrite composition comprises a main component and a subcomponent. The main component includes 32.0 to 46.4 mol % of iron oxide in terms of Fe.sub.2O.sub.3, 4.4 to 14.0 mol % of copper oxide in terms of CuO, and 8.4 to 56.9 mol % of zinc oxide in terms of ZnO. The subcomponent includes 0.53 to 11.00 parts by weight of a silicon compound in terms of SiO.sub.2, 0.1 to 12.8 parts by weight of a tin compound in terms of SnO.sub.2, and 0.5 to 7.0 parts by weight of a bismuth compound in terms of Bi.sub.2O.sub.3, with respect to 100 parts by weight of the main component.

A solid composition contains a first material and a powder and satisfies requirements 1 and 2. Requirement 1: |dA(T)/dT| satisfies 10 ppm/° C. or more at least at −200° C. to 1,200° C. A is (an a-axis lattice constant of a crystal in the powder)/(a c-axis lattice constant of a crystal in the powder), obtained from X-ray diffractometry of the powder. Requirement 2: C is 0.04 or more. C is (a log differential pore volume when a pore diameter of the solid composition is B in a pore distribution curve of the solid composition)/(a log differential pore volume corresponding to a maximum peak intensity in the pore distribution curve of the solid composition). B is (a pore diameter giving a maximum peak intensity in the pore distribution curve of the solid composition)/2. The pore distribution curve of the solid composition shows a relationship between the pore diameter and the log differential pore volume.

A polycrystalline diamond compact useful for wear, cutting, drilling, drawing and like applications is provided with a first diamond region remote from the working surface which has a metallic catalyzing material and a second diamond region adjacent to or including the working surface containing a non-metallic catalyst and the method of making such a compact is provided. This compact is particularly useful in high temperature operations, such as hard rock drilling because of the improved thermal stability at the working surface.

Components having an environmental barrier coating and a sintered layer overlying the environmental barrier coating, the sintered layer defining an outer surface having a lower surface roughness than the environmental barrier coating. The sintered layer is formed from a slurry applied to and then sintered on the environmental barrier coating. The sintered layer comprises a primary material, at least one sintering aid dissolved in the primary material, and optionally a secondary material. The sintering aid contains at least one doping composition. The primary material is a rare earth disilicate or a rare earth monosilicate and is doped with the doping composition so as to be either a doped rare earth disilicate or a doped rare earth monosilicate. The optional secondary material is a reaction product of the primary material and any of the sintering aid not dissolved in the primary material.