A reflective particulate material includes a particulate substrate having high total solar reflectance, bulk and apparent densities and toughness, and a low dust index. The reflective particulate can have a total solar reflectance of 80% to 87%, a toughness of 1% or fewer fines, an apparent density of 2.75 g/cm.sup.3 or greater, and a dust index of 1 or lower. A method of manufacturing the reflective particulate material includes preparing a slurry of the particulate substrate, spray drying the slurry to form a spray dried particulate, crushing the spray dried particulate to form a crushed particulate, and heating/calcining the crushed particulate. The heated, crushed particulate may further be coated to form a coated roofing granule.

A composite ceramic with improved mechanical performance and a preparation method therefor. The composite ceramic comprises fluorescent powder, a ceramic matrix, and an optional sintering aid. The weight ratio of the fluorescent powder to the ceramic matrix is from 3:17 to 9:1, and the relative density of the composite ceramic is greater than 95%. The preparation method comprises using core shell-structured coated fluorescent powder as a raw material, and ball-milling and sintering the raw material to obtain the composite ceramic.

An oxide sintered body containing indium, hafnium, tantalum, and oxygen as constituent elements, in which when indium, hafnium, and tantalum are designated as In, Hf, and Ta, respectively, the atomic ratio of Hf/(In+Hf+Ta) is equal to 0.002 to 0.030, and the atomic ratio of Ta/(In+Hf+Ta) is equal to 0.0002 to 0.013.

To provide a dental porcelain paste which can maintain maintaining the paste state and have excellent application property for a long period of time and hardly causes carbonization or bubbles due to the influence of an organic component or a polymer component during firing. The present invention provides a dental porcelain paste for preparing a dental prosthesis device, comprising: 50.0 to 80.0 wt. % of a glass powder (a) having a maximum particle diameter of 100 m or less and an average particle diameter of 1 to 20 m, 0.5 to 10.0 wt. % of a hydrophobized fine particle silica (b) having an average primary particle diameter of 1 to 50 nm, and 10.0 to 49.5 wt. % of an organic solvent (c) having a boiling point it is within (bp) of 100 to 300 C.

A composition comprises a zirconia powder, in which 55% or more thereof is monoclinic, and a stabilizer capable of suppressing phase transition of zirconia. An average particle diameter of zirconia particles and particles of the stabilizer is 0.06 m to 0.17 m. At least a portion of the stabilizer does not form a solid solution with zirconia.

A method of making a plurality of composite granules can include: forming green body granules comprising an aluminosilicate; heating the green body granules to form sintered granules; cooling the sintered granules according to a cooling regime, wherein the cooling regime comprises a temperature hold between 700 C. and 900 C. for at least one hour. In a particular embodiment, the aluminosilicate for making the composite granules can have a particle size less than 150 m. The composite granules are particularly suitable as roofing granules and can have a desired combination of high solar reflectance SR and low lightness L*, a low bulk density, good weather resistance and strength.

An optical wavelength converter (1) is configured such that an optical wavelength conversion member (9) is bonded to a heat dissipation member (13) having superior heat dissipation property. Thus, heat generated by light incident on the optical wavelength conversion member (9) can be efficiently dissipated. Therefore, even when high-energy light is incident on the optical wavelength converter, temperature quenching is less likely to occur, and thus high fluorescence intensity can be maintained. An intermediate film (21) is disposed between a reflective film (19) and a bonding portion (15). The presence of the intermediate film (21) improves the adhesion between the reflective film (19) and the bonding portion (15), thereby enhancing the heat dissipation from the optical wavelength conversion member (9) to the heat dissipation member (13). Thus, the temperature quenching of the optical wavelength conversion member (9) can be prevented, thereby enhancing fluorescence intensity.

A method for preparing polycrystalline fluoride ceramics using powder of fluoride ceramics nanocrystallites as starting material, wherein the method includes: (a) Optionally, a pre-processing step at a temperature ranging from 100 C. to 300 C. at vacuum of 10-5 mbar (10-3 Pa) to 10-8 mbar (10-6 Pa) for 30 minutes to 10 hours, (b) Applying a uniaxial pressure in the range from 1 to 200 MPa, at or around ambient temperature, to obtain a pre-compacted sample, (c) Applying to the pre-compacted of step b) a hydrostatic pressure by Cold Isostatic Pressing, to obtain a pre-compacted sample, (d) Loading the pre-compacted sample from step (c) into a die and submitting the sample to a uniaxial compression in combination with electric field-assisted sintering, under vacuum equal to or higher than 5 Pa. Polycrystalline fluoride ceramics obtained by this method find use in IR devices.

The durability of a ceramic sintered body is improved, and a reduction in its light emission intensity and the occurrence of a chromaticity variation are suppressed. The ceramic sintered body contains alumina and a compound represented by M1.sub.3-XM2.sub.XM3.sub.5O.sub.12. The volume percent of the compound in the ceramic sintered body is from 3% to 70% inclusive. The ratio of the intensity of XRD from a complex oxide of aluminum and M2 to the intensity of XRD from the compound in the ceramic sintered body is less than 0.05. The average grain diameter of the alumina contained in the ceramic sintered body is from 0.30 (m) to 3.00 (m) inclusive. M1 is at least one selected from Sc, Y, and lanthanoid elements, and M2 is at least one selected from lanthanoid elements except any lanthanoid element selected for M1. M3 is at least one of Al and Ga, and X is from 0.003 to 0.500 inclusive.

A translucent polycrystalline cubic boron nitride body is provided. It comprises no more than 2 weight % hexagonal boron nitride grains and has an absorption coefficient of less than 100 cm.sup.1 at a wavelength of 1064 nm.