A sintered body, containing zinc, magnesium and oxygen as constituent elements, wherein the atomic ratio of zinc to the sum of zinc and magnesium [Zn/(Zn+Mg)] is 0.20 to 0.75, the atomic ratio of magnesium to the sum of zinc and magnesium [Mg/(Zn+Mg)] is 0.25 to 0.80, and the sintered body consists of a single crystal structure as measured by X-ray diffraction.

The present invention provides a gallium nitride sintered body and a gallium nitride molded article which have high density and low oxygen content without using a special apparatus. According to the first embodiment, a gallium nitride sintered body, which is characterized by having density of 2.5 g/cm.sup.3 to less than 5.0 g/cm.sup.3 and an intensity ratio of the gallium oxide peak of the (002) plane to the gallium nitride peak of the (002) plane of less than 3%, which is determined by X-ray diffraction analysis, can be obtained. According to the second embodiment, a metal gallium-impregnated gallium nitride molded article, which is characterized by comprising a gallium nitride phase and a metal gallium phase that exist as separate phases and having a molar ratio, Ga/(Ga+N), of 55% to 80%, can be obtained.

A composite material consisting of a matrix made of at least one aluminosilicate notably selected from barium aluminosilicate BAS, barium and strontium aluminosilicate BSAS, strontium aluminosilicate SAS, and mixtures thereof, reinforced by reinforcements made of at least one metal or metalloid oxide, the expansion coefficient of which is close to that of said at least one aluminosilicate.

A method for preparing said composite material.

A composite material according to the invention notably finding its application in the aeronautical or aerospace field, for example for the manufacture of radomes.

A slurry or slip composed of a dispersion medium and a dispersoid including sinterable raw material powder containing a complex oxide powder represented by the following formula (1):
(Tb.sub.1-x-yR.sub.xSc.sub.y).sub.3(Al.sub.1-zSc.sub.z).sub.5O.sub.12  (1)
wherein R is yttrium and/or lutetium, 0.05≤x<0.45, 0<y<0.1, 0.5<1-x-y<0.95, and 0.004<z<0.2 is prepared; the slurry or slip is subsequently enclosed in a mold container to be subjected to solid-liquid separation by centrifugal casting to mold a cast compact; the cast compact is dried thereafter; a dried compact is degreased; a degreased compact is sintered thereafter; and a sintered body is further subjected to a hot isostatic pressing treatment to obtain the transparent ceramic material composed of the sintered body of garnet-type rare earth complex oxide represented by the formula (1).

A paramagnetic garnet-type transparent ceramic that exhibits a high laser damage threshold, said ceramic being a sintered body of a Tb-containing rare earth-aluminum garnet represented by formula (1), and being characterized in that the average sintered grain size is 10-40 μm, and the insertion loss at a wavelength of 1,064 nm in the optically effective region along the length direction of a 20 mm-long sample is 0.05 dB or less.

(Tb.sub.1-x-yY.sub.xSc.sub.y).sub.3(Al.sub.1-zSc.sub.z).sub.5O.sub.12  Formula (1)

(In the formula, 0≤x<0.45, 0≤y<0.08, 0≤z<0.2, and 0.001<y+z<0.20.)

A ceramic lithium indium diselenide or like radiation detector device formed as a pressed material that exhibits scintillation properties substantially identical to a corresponding single crystal growth radiation detector device, exhibiting the intrinsic property of the chemical compound, with an acceptable decrease in light output, but at a markedly lower cost due to the time savings associated with pressing versus single crystal growth.

In an aspect, an M-type ferrite, comprises oxides of Me, Me′, Me″, Co, Ti, and Fe; wherein Me is at least one of Ba, Sr, or Pb; Me′ is at least one of Ti, Zr, Ru, or Ir; and Me″ is at least one of Mg or Ca. In another aspect, a method of making an M-type ferrite comprises milling ferrite precursor compounds comprising oxides of at least Co, Fe, Ti, Me, Me′, and Me″, to form an oxide mixture; wherein Me comprises at least one of Ba, Sr, or Pb; Me′ is at least one of Ti, Zr, Ru, or Ir; and Me″ is at least one of Mg or Ca; and calcining the oxide mixture in an oxygen or air atmosphere to form the M-type ferrite.

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 sintered body, containing zinc, magnesium and oxygen as constituent elements, wherein the atomic ratio of zinc to the sum of zinc and magnesium [Zn/(Zn+Mg)] is 0.20 to 0.75, the atomic ratio of magnesium to the sum of zinc and magnesium [Mg/(Zn+Mg)] is 0.25 to 0.80, and the sintered body consists of a single crystal structure as measured by X-ray diffraction.

A honeycomb structure according to at least one embodiment of the present invention includes: partition walls defining cells each extending from a first end surface of the honeycomb structure to a second end surface thereof to form a fluid flow path; and an outer peripheral wall. The partition walls and the outer peripheral wall are each formed of ceramics containing silicon carbide and silicon. A surface of the silicon has formed thereon an oxide film having a thickness of from 0.1 μm to 5.0 μm.