Methods of flash sintering have been developed in which particle are initially coated with thin layers by atomic layer deposition (ALD). Examples are provided in which 8 mol % yttria-stabilized zirconia (8YSZ) particles are coated with small quantities of Al.sub.2O.sub.3 by particle atomic layer deposition (ALD). Sintered materials that result from the process have been characterized. Sintered materials having unique characteristics are also described.

A method of forming a water resistant boundary on a fissile material for use in a water cooled nuclear reactor is described. The method comprises mixing a powdered fissile material selected from the group consisting of UN and U.sub.3Si.sub.2 with an additive selected from oxidation resistant materials having a melting or softening point lower than the sintering temperature of the fissile material, pressing the mixed fissile and additive materials into a pellet, sintering the pellet to a temperature greater than the melting point of the additive. Alternatively, if the melting point of the oxidation resistant particles is greater than the sintering temperature of UN or U.sub.3Si.sub.2, then the oxidation resistant particles can have a particle size distribution less than that of the UN or U.sub.3Si.sub.2.

Exemplary deposition methods may include introducing hydrogen into a processing chamber, a powder disposed within a processing region of the processing chamber. The method may include striking a first plasma in the processing region, the first plasma including energetic hydrogen species. The method may include exposing the powder to the energetic hydrogen species in the processing region. The method may include chemically reducing the powder through a reaction of the powder with the energetic hydrogen species. The method may include removing process effluents including unreacted hydrogen from the processing region. The method may also include forming a layer of material on grains of the powder within the processing region.

A method of forming a water resistant boundary on a fissile material for use in a water cooled nuclear reactor is described. The method comprises mixing a powdered fissile material selected from the group consisting of UN and U.sub.3Si.sub.2 with an additive selected from oxidation resistant materials having a melting or softening point lower than the sintering temperature of the fissile material, pressing the mixed fissile and additive materials into a pellet, sintering the pellet to a temperature greater than the melting point of the additive. Alternatively, if the melting point of the oxidation resistant particles is greater than the sintering temperature of UN or U.sub.3Si.sub.2, then the oxidation resistant particles can have a particle size distribution less than that of the UN or U.sub.3Si.sub.2

A method of manufacturing a multilayer ceramic electronic component includes: preparing a dielectric magnetic composition including base material powder particles including BaTi.sub.2O.sub.5 or (Ba.sub.(1-x)Ca.sub.x)Ti.sub.2O.sub.5 (0≤x≤0.1), the base material powder particles having surfaces coated with one or more of Mg, Mn, V, Ba, Si, Al and a rare earth metal; preparing ceramic green sheets using dielectric slurry including the dielectric magnetic composition; applying an internal electrode paste to the ceramic green sheets; preparing a green sheet laminate by stacking the ceramic green sheets to which the internal electrode paste is applied; and preparing a ceramic body including dielectric layers and a plurality of first and second internal electrodes arranged to face each other with each of the dielectric layers interposed therebetween by sintering the green sheet laminate.

A method of forming a water resistant boundary on a fissile material for use in a water cooled nuclear reactor is described. The method comprises mixing a powdered fissile material selected from the group consisting of UN and U.sub.3Si.sub.2 with an additive selected from oxidation resistant materials having a melting or softening point lower than the sintering temperature of the fissile material, pressing the mixed fissile and additive materials into a pellet, sintering the pellet to a temperature greater than the melting point of the additive. Alternatively, if the melting point of the oxidation resistant particles is greater than the sintering temperature of UN or U.sub.3Si.sub.2, then the oxidation resistant particles can have a particle size distribution less than that of the UN or U.sub.3Si.sub.2.

An alumina sintered body including an inner layer in which alumina crystal grains contained have an average aspect ratio of 1.0 to 2.0 and an outer layer which covers at least a part of the inner layer from outside and in which alumina crystal grains contained have an average aspect ratio of more than 2.0, the alumina sintered body being free from silicon except unavoidable impurities.

A sensor element of a gas sensor includes: an element base which is a ceramic structured body including a detection part of detecting a target measurement gas component; and a protective layer which is a porous layer provided in at least a part of an outermost peripheral portion of the element base, wherein in the protective layer, numerous convex parts each having a size of 1.0 μm or less and made up of ceramic microparticles with diameters of 10 nm to 1.0 μm are discretely formed around numerous ceramic coarse grains having diameters of 5.0 μm to 40 μm, the respective ceramic coarse grains are connected to each other directly or via the ceramic microparticle, and a degree of porosity of the protective layer is 5% to 50%.

A ceramic particle includes a core and a modification layer. The core is made of magnesium or a magnesium alloy. The core has a diameter of 30-100 μm. The modification layer covers an outer surface of the core. The modification layer includes calcium and phosphorus. A method for producing a ceramic particle includes providing a core made of magnesium or a magnesium alloy and having a diameter of 30-100 μm. A calcium salt and a phosphorus salt are dissolved in a solvent. A chelating agent is added into the solvent to form a modifying solution. The core is added into the modifying solution to form a modification layer on an outer surface of the core in a temperature range of 5-40° C. The modification layer includes calcium and phosphorus.

A sensor element of a gas sensor includes: an element base which is a ceramic structured body including a detection part of detecting a target measurement gas component; an outer protective layer which is a porous layer provided in at least a part of an outermost peripheral portion of the element base; and an inner protective layer which is a porous layer having a degree of porosity of 30% to 85%, which is larger than a degree of porosity of the outer protective layer, inside the outer protective layer, wherein an average fine pore diameter of the inner protective layer is equal to or larger than 0.5 μm and equal to or smaller than 5.0 μm.