Abstract:
PROBLEM TO BE SOLVED: To provide a cerium oxide powder, a method for producing the same, and a dispersion liquid containing the powder. SOLUTION: The cerium oxide powder has a BET surface area of 25-150 m 2 /g and contains primary particles having an average diameter of 5-50 nm. The layer close to the surface of each primary particle has a depth of about 5 nm, and the carbonate concentration in the layer close to the surface is decreased toward inside from the surface. The content of carbon deriving from carbonate groups is 5-50% by area percentage on the surface and 0-30% by area percentage at a depth of about 5 nm in the layer close to the surface. The content of cerium oxide is at least 99.5 mass% based on powder. Further, the content of carbon is 0.01-0.3 mass% based on powder. The dispersion liquid is sufficiently stable even when an additive is not added additionally and can be used for chemical and mechanical polishing within a range from neutrality to weak alkalinity. COPYRIGHT: (C)2007,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a method of making metal oxide powder by which uniform powders having high BET surface area and narrow particle size distribution can be obtained and suitable for making the metal oxide powder in a range of quantity of kg/hr order. SOLUTION: In the method of making the metal oxide powder having at least 20 m 2 /g BET surface area by reacting aerosol with oxygen in a reaction space at a reaction temperature higher than 700°C and successively separating the resultant powder from a gaseous material, the aerosol is produced by spraying at least one kind of a starting material in a liquid form or a solution and at least one kind of a spray gas using a multi-component nozzle so that the average liquid particle diameter D 30 of the aerosol to the volume is 30-100 μm and the number of aerosol small droplets having a particle diameter larger than 100 μm is ≤10% of the total number of droplets. COPYRIGHT: (C)2006,JPO&NCIPI
Abstract:
PROBLEM TO BE SOLVED: To provide an improved method for producing a zinc oxide powder without generating a cake-like material in an evaporation zone and an oxidation zone. SOLUTION: In the evaporation zone, a gas flow of an inert gas and a fuel gas is passed through a melt of zinc having a temperature of 780-850°C while forming zinc vapor. In this case, the content of the fuel gas is 1-50 vol.% based on the total volume of the inert gas and the fuel gas, and the molar ratio of the zinc vapor to the fuel gas is 0.01-50. In the oxidation zone, a second gas flow containing an oxygen-containing gas and steam is added to a gas flow of the zinc vapor, the fuel gas, and the inert gas in such an amount that the temperature in the oxidation zone is kept within a range of 500-1,000°C. COPYRIGHT: (C)2007,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a method of manufacturing an approximately nano-degree thermal decomposition method oxide having a minimal chloride content and a BET surface area of 1-600 m 2 /g without necessitating an extremely high vaporization temperature. SOLUTION: This oxide is obtained by dissolving an organic metal material in a solvent and converting it into an oxide in a flame at a temperature over 200°C. COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To prepare a cerium oxide powder suitable as a component of a dispersion for grinding a semiconductor substrate, easily incorporated and having high stability to precipitation. SOLUTION: The polycrystalline cerium oxide powder in a form of primary particle aggregate has 70-150 m 2 /g specific surface area, 5-20 nm average primary particle diameter and 20-100 nm projected average aggregate diameter. COPYRIGHT: (C)2005,JPO&NCIPI
Abstract:
PROBLEM TO BE SOLVED: To provide composite powder having a matrix domain structure. SOLUTION: The composite powder has the matrix domain structure in which the matrix is a metal oxide and is present in the form of three dimensional aggregate having ≤250 nm diameter at least in one dimension and the domains consist of metal oxides and/or nobel metals in the matrix of individual metal oxide. In such a case, the domains consist of at least two metal oxides, at least two noble metals or a mixture of at least one metal oxide with at least one noble metal and are nano scale and the composite powder has 60-1,200 m 2 /cm 3 volume-specific surface area. The composite powder is produced by mixing the precursors of the matrix and of the domains corresponding to the subsequently desired ratio with a gaseous mixture containing a combustible gas and oxygen, reacting in the reactor consisting of a combustion zone and a reaction zone, cooling the hot gas and a solid product and separating from the gas. The composite powder is used as a material for magnetic, electronic or optical applications. COPYRIGHT: (C)2005,JPO&NCIPI
Abstract:
PROBLEM TO BE SOLVED: To provide nano size oxide with a slight amount of chloride and BET specific surface area of 1-600 m2/g through a thermo-decomposition method which does not need an extremely high evaporation temperature. SOLUTION: In manufacturing through a thermo-decomposition of metal and/or metalloid, oxide and/or mixed oxide in nano size is controlled to become 1-600 m2/g in BET specific surface area and less than 0.05 mass % in total chloride content.
Abstract:
PROBLEM TO BE SOLVED: To provide the almost spherical and excellently flowable grains, each of which has a homogeneous structure and which are completely redispersed under the condition necessary to disperse the starting solids. SOLUTION: The discrete granules are almost spherical grains having a uniform density distribution and can be completely redispersed under the condition used in the starting solids. The granule consists of the dispersible fine solids having
Abstract:
Process for preparing a mixed metal oxide powder, in which oxidizable starting materials are evaporated and oxidized, the reaction mixture is cooled after the reaction and the pulverulent solids are removed from gaseous substances, wherein as starting materials, at least one pulverulent metal and at least one metal compound, the metal and the metal component of the metal compound being different and the proportion of metal being at least 80% by weight based on the sum of metal and metal component from metal compound, together with one or more combustion gases, are fed to an evaporation zone of a reactor, where metal and metal compound are evaporated completely under nonoxidizing conditions, subsequently, the mixture flowing out of the evaporation zone is reacted in the oxidation zone of this reactor with a stream of a supplied oxygen-containing gas whose oxygen content is at least sufficient to oxidize the starting materials and combustion gases completely.
Abstract:
Process for preparing a metal oxide powder, in which starting materials are evaporated and oxidized, wherein a metal melt in the form of droplets and one or more combustion gases are fed to the evaporation zone of a reactor, where the metal melt is evaporated completely under nonoxidizing conditions, subsequently, the mixture flowing out of the evaporation zone is reacted in the oxidation zone of this reactor with a stream of a supplied oxygen-containing gas whose oxygen content is at least sufficient to oxidize the metal and the combustion gases completely.