Disclosed is a ceramic sintered body comprising yttrium oxide and zirconium oxide wherein the ceramic sintered body comprises not less than 75 mol % to not greater than 95 mol % yttrium oxide and not less than 5 mol % to not greater than 25 mol % zirconium oxide, wherein the ceramic sintered body comprises porosity in an amount of less than 2% by volume, wherein a density of the ceramic sintered body does not vary by more than 2% relative to theoretical density across a greatest dimension. The ceramic sintered body has a grain size of from 0.4 to less than 2 um as measured according to ASTM E1 12-2010. The ceramic sintered body may be machined into plasma resistant components for use in plasma processing chambers. Methods of making are also disclosed.

An inorganic fiber containing silica, alumina, one or more alkali metal oxides, and one or more of alkaline earth metal oxides, transition metal oxides, or lanthanide series metal oxides. The inorganic fiber exhibits good thermal performance at use temperatures of 1260 C. and greater, retains mechanical integrity after exposure to the use temperatures, is free of crystalline silica upon devitrification, is alkali flux resistant, exhibits low bio-persistence in an acidic medium, and exhibits low dissolution in a neutral medium. Also provided are thermal insulation products incorporating the inorganic fibers, a method for preparing the inorganic fiber and a method of thermally insulating articles using thermal insulation prepared from the inorganic fibers.

A sintered body of the present invention contains yttrium oxyfluoride. The yttrium oxyfluoride is preferably YOF and/or Y.sub.5O.sub.4F.sub.7. The sintered body of the present invention preferably contains 50% by mass or more of yttrium oxyfluoride. The sintered body of the present invention has a relative density of preferably 70% or more and an open porosity of preferably 10% or less. Furthermore, the sintered body of the present invention has a three-point bending strength of preferably 10 MPa or more and 300 MPa or less.

A refractory object may include a zircon body that may include at least about 0.1 wt. % and not greater than about 5.5 wt. % of an Al.sub.2O.sub.3 containing component for a total weight of the zircon body. The zircon body may further include at least about 25 wt. % and not greater than about 35 wt. % of a SiO.sub.2 component for a total weight of the zircon body.

The present disclosure relates to an electrolytic cell for the production of aluminium by reducing alumina. The cell may comprise a sidewall including at least one side block. The side block may comprise an aluminous material having an apparent porosity of less than about 10% and a composition, as a weight percentage on the basis of the aluminous material and for a total of about 100%, such that: Al2O3>about 50%, beta-alumina being less than about 20% of the weight of the aluminous material, oxides that are less reducible than alumina at 1000 C.<about 50%, Na2O<about 3.9%, and other components<about 5%.

A powder is disclosed having a coarse fraction representing more than 60% and less than 85% of the powder, as a weight percentage on the basis of the oxides, and that is constituted of particles having a size greater than or equal to 50 m, referred to as coarse particles, the powder comprising at least 5% of coated grains having a size greater than or equal to 50 m, as a weight percentage on the basis of the oxides of the powder, and a fine fraction, forming the balance to 100% as a weight percentage on the basis of the oxides, constituted of particles having a size of less than 50 m, referred to as matrix particles. The powder can be applied in combustion chambers in which the temperature may reach 1400 C.

A method of forming an improved sealed joint between two or more shaped ceramic structures includes providing at least first and second ceramic structures joined together by a joint comprising one or more of silicon, a silicon alloy and a silicon compound, the joint including an exposed portion interior of the joined structures, then converting at least a portion of the one or more of silicon, a silicon alloy, and a silicon compound of the joint to silicon nitride and/or silicon carbide, desirably at least at an interior exposed portion of the joint, so as to provide increased chemical resistance for the joint when aggressive chemicals are used within device formed from the sealed-together ceramic structures. The ceramic structures desirably comprise silicon carbide.

A corrosion-resistant component configured for use with a semiconductor processing reactor, the corrosion-resistant component comprising: a) a ceramic insulating substrate; and, b) a white corrosion-resistant non-porous outer layer associated with the ceramic insulating substrate, the white corrosion-resistant non-porous outer layer having a thickness of at least 50 m, a porosity of at most 1%, and a composition comprising at least 15% by weight of a rare earth compound based on total weight of the corrosion-resistant non-porous layer; and, c) an L* value of at least 90 as measured on a planar surface of the white corrosion-resistant non-porous outer layer. Methods of making are also disclosed.

An alumina sintered body according to the present invention has a degree of c-plane orientation of 90% or more as determined by Lotgering's method from an X-ray diffraction profile obtained by irradiating a plate surface with X-rays in a range of 2=20 to 70. The alumina sintered body has no pores when a cross-sectional surface formed in a direction perpendicular to the plate surface is polished using an Ar.sup.+ ion beam and a mask and is examined under a scanning electron microscope at a magnification of 5,000 times. The alumina sintered body has a total mass fraction of impurity elements other than Mg and C of 100 ppm or less. This alumina sintered body has a high degree of orientation, high density, and high purity and thus has a higher optical translucency than those known in the art.

Methods for forming monolithic refractory compositions may include providing a particulate refractory composition including 2 to 90 mass-% alumina, aluminosilicate, or mixtures thereof; 2 to 70 mass-% silicon carbide; 2 to 10 mass-% carbon; 1 to 10 mass-% Si powder; 1 to 3 mass-% microsilica; and up to 5 mass-% ferrosilicon. The methods may further include adding an amount of water to the particulate refractory composition to form a uniform mixture, installing the uniform mixture and allowing it to set, such that the monolithic refractory composition is required, and heat-treating the set mixture at a temperature no higher than 1200 C. under atmospheric conditions to form a monolithic refractory composition. The methods may optionally include heat-treating the obtained monolithic refractory composition to form silicon carbide whiskers within the monolithic refractory composition.