The invention relates to a method of manufacturing a ceramic molding, comprising the following steps: a) providing three or more ceramic powder layers that are arranged in layers, one on top of the other, to form a compression-molded element and sintering the compression-molded element obtained in step b) to form a ceramic molding, characterized in that the ceramic powder layers have different compositions, each ceramic powder layer comprising a mixture of at least two different base powders and each base powder containing at least 80 wt. % ZrO.sub.2 and at least 0.02 wt. % Al.sub.2O.sub.3, each weight amount being relative to the total weight of the constituents of the base powder.

The invention relates to a sintered molding with a color gradient for use in the manufacture of dental restorations, obtainable by sintering a compression-molded element comprising five or more different ceramic powder layers, each powder layer comprising at least two different base powders and each base powder containing at least 80 wt. % ZrO.sub.2, each weight amount being relative to the total weight of the base powder.

A polycrystalline YAG sintered body, wherein, when dimensions of a smallest rectangular solid surrounding a YAG sintered body are A mm×B mm×C mm, a maximum value (A, B, C) is 150 mm or less, a minimum value (A, B, C) is more than 20 mm and 40 mm or less, and an optical loss coefficient when light of a wavelength of 300 to 1500 nm (excluding wavelengths which result in absorption of light by an additive element) is transmitted therethrough is 0.002 cm.sup.−1 or less. Moreover, a polycrystalline YAG sintered body, wherein, when dimensions of a smallest rectangular solid surrounding a YAG sintered body are A mm×B mm×C mm, a maximum value (A, B, C) is more than 150 mm and 300 mm or less, a minimum value (A, B, C) is more than 5 mm and 40 mm or less, and an optical loss coefficient when light of a wavelength of 300 to 1500 nm (excluding wavelengths which result in absorption of light by an additive element) is transmitted therethrough is 0.002 cm.sup.−1 or less. An object of an embodiment of the present invention is to provide a large and transparent polycrystalline YAG sintered body and its production method.

A synergistic disposal method of hazardous waste incineration residues and solid wastes, ceramsite and an application thereof, all belonging to the field of resources and environment. The disposal method includes the following steps: mixing of the hazardous waste incineration residues and solid wastes, granulation and dehydration of the resulting mixture and calcination to obtain ceramsite. In the preparation of ceramsite by the synergistic disposal of hazardous waste incineration residues and solid wastes as the raw materials, dioxin and organic matters in the hazardous waste incineration residues and solid wastes are decomposed, meanwhile the contained heavy metals are reduced and solidified, solving the disposal problem of hazardous waste incineration residues and solid wastes, saving a lot of land for landfills, decreasing the cost for comprehensive disposal, not producing new hazardous wastes, and reducing the burden of ecological environment.

A magnetic material which is likely to be cracked or chipped. The magnetic material is a magnetic material including ferrite particles and segregated particles containing Bi and Si, and characteristically, the magnetic material contains, as a main constituent, 46.0 mol % to 50.0 mol % Fe.sub.2O.sub.3, 0.4 mol % to 8.0 mol % CuO, 23.0 mol % to 32.0 mol % ZnO, and 18.0 mol % to 22.0 mol % NiO, and the ratio of the average particle size of the segregated particles to the average particle size of the ferrite particles is 0.04 or more and 0.19 or less (i.e., 0.04 to 0.19).

A powder formed of fused particles. More than 95% by number of the feed particles exhibiting a circularity of greater than or equal to 0.85. The powder contains more than 88% of a silicate of one or more elements chosen from Zr, Hf, Y, Ce, Sc, In, La, Gd, Nd, Sm, Dy, Er, Yb, Eu, Pr, Ho and Ta, less than 10% of a dopant, as percentage by weight based on the oxides. The powder has a median particle size D.sub.50 of less than 15 μm, a 90 percentile particle size, D.sub.90, of less than 30 μm, and a size dispersion index (D.sub.90-D.sub.10)/D.sub.10 of less than 2. The powder has a relative density of greater than 90%. The D.sub.n percentiles of the powder are the particle sizes corresponding to the percentages, by number, of n %, on the cumulative distribution curve of the size of the particles of the powder. The particle sizes are classified in increasing order.

A crucible having a heat treated body. The heat treated body comprises a composition including an oxide material, from 5 wt % to 50 wt % a nitride material, and optionally a sintering aid. A weight ratio of the nitride material to the oxide material ranges from 0.02:1 to 2.0:1. The heat treated body has an oxide material lattice structure with nitride material at least partially encapsulated therein.

A tungsten carbide powder contains tungsten carbide as a main component and chromium, in which, when mass concentrations of tungsten and chromium are measured at 100 or more analysis points randomly selected from a field of view of SEM observation of the tungsten carbide powder, a standard deviation σ of distribution of the ratio by percentage of the concentration of chromium to the total concentration of tungsten and chromium is 0.5 or less.

A dielectric composition including a complex oxide containing bismuth, zinc, and niobium, includes a crystal phase formed of the complex oxide and having a pyrochlore type crystal structure, and an amorphous phase. When the complex oxide is represented by a composition formula Bi.sub.xZn.sub.yNb.sub.zO.sub.1.75+δ, in which x, y, and z satisfy relations of x+y+z=1.00, 0.20≤y≤0.50, and 2/3≤x/z≤3/2.

A ceramic honeycomb filter comprising a cordierite-type ceramic honeycomb structure having large numbers of flow paths partitioned by porous cell walls, and plugs formed in end portions of predetermined flow paths of the ceramic honeycomb structure; the cell walls having a thermal expansion coefficient Tw (×10.sup.−7/° C.) of 10 or less in the flow path direction between 40° C. and 800° C.; the plugs comprising at least ceramic particles, and 5-25 parts by mass of an amorphous oxide matrix per 100 parts by mass of the ceramic particles; the ceramic particles comprising at least 42-90% by mass of amorphous silica particles, and 10-58% by mass of cordierite particles; and the amorphous silica particles comprising 4-30% by mass of first silica particles having a median particle diameter of 10-40 μm, and 70-96% by mass of second silica particles having a median particle diameter of 70-200 μm.