590results about "Rare earth metal oxides/hydroxides" patented technology

A homogeneous ceria-based mixed-metal oxide, useful as a catalyst support, a co-catalyst and/or a getter, is described. The mixed-metal oxide has a relatively large surface area per weight, typically exceeding 150 m<2>/g, a structure of nanocrystallites having diameters of less than 4 nm, and including pores larger than the nanocrystallites and having diameters in the range of 4 to about 9 nm. The ratio of the pore volumes, VP, to skeletal structure volumes, VS, is typically less than about 2.5, and the surface area per unit volume of the oxide material is greater than 320 m<2>/cm<3>, such that the structural morphology supports both a relatively low internal mass transfer resistance and large effective surface area for reaction activity of interest. The mixed metal oxide is made by co-precipitating a dilute metal salt solution containing the respective metals, which may include Zr, Hf, and/or other metal constituents in addition to Ce, replacing water in the co-precipitate with a water-miscible low surface-tension solvent, and relatively quickly drying and calcining the co-precipitate at moderate temperatures. A highly dispersive catalyst metal, such as Pt, may be loaded on the mixed metal oxide support from a catalyst-containing solution following a selected acid surface treatment of the oxide support. The mixed metal oxide, as catalyst support, co-catalyst or getter, is applied in various reactions, and particularly water gas shift and/or preferential oxidation reactions as associated with fuel processing systems, as for fuel cells and the like.

A liquid suspension of phosphor particles and method for depositing the liquid suspension. The suspension advantageously has a low viscosity with a high solids-loading of phosphor particles. The apparent density of the phosphor particles is well-controlled to enable the particles to be dispersed in the liquid vehicle. The suspension is useful in direct-write tools such as ink-jet devices.

A turbine component has a substrate formed from a ceramic material selected from the group consisting of a monolithic ceramic material and a composite ceramic material and a thermal barrier coating bonded to the substrate. In one embodiment, the ceramic material forming the substrate is selected from the group of silicon nitride and self-reinforced silicon nitride. In another embodiment, the ceramic material forming the substrate is selected from the group consisting of a silicon carbide-silicon carbide material and a carbon-carbon material. At least one bond coat layer may be interposed between the substrate and the thermal barrier coating.

The present invention relates to a thermal barrier coating material having the chemical composition of (1−n)CeO₂-nZrO₂-0.5R₂O₃, where n is in the range of 0.9≧n≧0 and R is selected from a group consisting of Nd, Sm, Eu, Gd, Tb and combinations of at least two among them. It possesses a thermal expansion coefficient higher than 12×10⁻⁶ K⁻¹ from ambient temperature up to 1200° C. and superior to those of the presently widely-used thermal barrier coating materials. Even if it is subjected to long time calcinations at 1400° C. or is quenched to room temperature, it can still maintain the stable crystal structure. In addition, its thermal expansion trend matches quite well with that of the bond coating alloy. This is beneficial to the elimination of thermal stress generated between the substrate and the ceramic top coating during the thermal cycle and can significantly improve the thermal shock resistance of the coating. The present invention further relates to a method for producing a thermal barrier coating material and a method for preparing a thermal barrier coating.

Described is a method to prepare wet foams exhibiting long-term stability wherein colloidal particles are used to stabilize the gas-liquid interface, said particles being initially inherently partially lyophobic particles or partially lyophobized particles having mean particle sizes from 1 nm to 20 μm. In one aspect, the partially lyophobized particles are prepared in-situ by treating initially hydrophilic particles with amphiphilic molecules of specific solubility in the liquid phase of the suspension.

Described is a method for the production of pure or mixed metal oxides, wherein at least one metal precursor that is a metal carboxylate with a mean carbon value per carboxylate group of at least 3, e.g. the 2-ethyl hexanoic acid salt, is formed into droplets and e.g. flame oxidized. The method is performed at viscosities prior to droplet formation of usually less than 40 mPa s, obtained by heating and/or addition of one or more low viscosity solvents with adequately high enthalpy.

Crystalline scintillator materials comprising nano-scale particles of metal oxides, metal oxyhalides and metal oxysulfides are provided. The nano-scale particles are less than 100 nm in size. Methods are provided for preparing the particles. In one method, used to form oxyhalides and oxysulfides, metal salts are dissolved in water, and then precipitated out as fine particles using an aqueous base. After the particles are separated from the solution, they are annealed under a flow of a water saturated hydrogen anion gas, such as HCl or H₂S, to form the crystalline scintillator particles. The other methods take advantage of the characteristics of microemulsion solutions to control droplet size, and, thus, the particle size of the final nano-particles. For example, in one method, a first micro-emulsion containing metal salts if formed. The first micro-emulsion is mixed with an aqueous base in a second micro-emulsion to form the final nano-scale particles.

The invention provides a method for recovering rare earth, aluminum and silicon from rare earth-containing aluminum and silicon wastes. The method comprises the following steps: 1, carrying out acid dipping on the rare earth-containing aluminum and silicon wastes by using an aqueous inorganic acid solution to obtain silicon-rich residues and an acid dipping solution containing rare earth ions and aluminum ions; 2, adding an alkaline substance to the acid dipping solution containing rare earth ions and aluminum ions to control the pH value of the acid dipping solution to be 3.5-5.2, and carrying out solid-liquid separation to obtain an aluminum hydroxide-containing precipitate and a rare earth-containing filtrate; and 3, reacting the aluminum hydroxide-containing precipitate with sodium hydroxide to obtain a sodium metaaluminate solution and aluminum and silicon residues, and using the rare earth-containing filtrate to prepare a rare earth compound product. Aluminum and rare earth are dissolved in the acid, segmented alkaline transfer is carried out, the aluminum ions are precipitated to obtain aluminum hydroxide and the rare earth ions which are separated from the aluminum hydroxide, and excess sodium hydroxide is added to convert aluminum hydroxide into the sodium metaaluminate solution, so simultaneous and high-efficiency recycling of the rare earth and aluminum is realized, the use amount of sodium hydroxide is greatly reduced, and the recovery cost is reduced.

The invention relates to a preparation method of superfine yttrium oxide doped tungsten composite precursor powder. The preparation method comprises the steps: dissolving ammonium paratungstate, yttrium nitrate hexahydrate and a surfactant into water, and carrying out sufficient dispersion and dissolution through mechanical stirring and ultrasonic treatment to prepare a solution; adding concentrated HNO3 into the solution under stirring and ultrasonics to carry out precipitation reaction to form a suspension liquid; adding absolute ethyl alcohol into the suspension liquid to further react, filtering the reacted suspension liquid, and cleaning a precipitate by using absolute ethyl alcohol or distilled water; after drying the precipitate, grinding the precipitate to obtain composite powder, then, placing the composite powder into a tube furnace, and calcining the composite powder in a nitrogen or argon flow to obtain W-Y2O3 composite oxide powder; and carrying out two-step reduction in the tube furnace by using pure hydrogen to obtain the superfine yttrium oxide doped tungsten composite precursor powder. The average grain size of the powder reaches about 10nm, and the uniformity of the grain size is good. Meanwhile, Y2O3 is also uniformly doped, which provides a good basis for subsequent calcination for obtaining fine-grain compact tungsten-based alloy.

Compositions and processes are disclosed for removing sulfur and sulfur compounds from hydrocarbon fuel feedstocks. The feedstock is contacted with a regenerable sorbent such as a compound of the formula Ti_xCe_yO₂ where 0<x/y≦1 and where 0<x≦1 and 0<y≦1 capable of selectively adsorbing sulfur compounds present in the hydrocarbon feedstock at about 0° C. to about 100° C. such as at about 25° C.

The invention belongs to the technical field of water treatment, and relates to mesoporous flower-shaped CeO2, a preparation method thereof and an application thereof as mimic oxidase to degrade wastewater containing reactive light yellow. The mesoporous flower-shaped CeO2 is a hollow type crystal consisting of a plurality of small particles with an average particle diameter of 214 nm. The preparation method comprises the following steps: firstly, by adopting CeCl3.7H2O as a cerium source, adopting urea as a precipitator and adopting PVP as a surfactant, preparing a CeO2 precursor under high pressure at a high temperature through a hydrothermal method; and roasting the precursor at a high temperature, thereby preparing a light yellow CeO2 nano material. According to the TMB chromogenic reaction, the prepared CeO2 has characteristics of mimic enzyme. The mesoporous flower-shaped CeO2 is used for reactive light yellow catalytic degradation reaction, so that the degradation rate of the reactive light yellow can be about 95% under the optimum proportion condition, and therefore, the mesoporous flower-shaped CeO2 has relatively good application prospects.

Chemical-mechanical planarization slurries and methods for using the slurries wherein the slurry includes abrasive particles. The abrasive particles have a small particle size, narrow size distribution and a spherical morphology and the particles are substantially unagglomerated.

A zirconium-cerium composite oxide having excellent heat resistance and being capable of maintaining its large specific surface area even when used under high-temperature conditions, which composite oxide contains zirconium and cerium at a weight ratio of 51 to 95:49 to 5 in terms of zircomium oxide and ceric oxide, the composite oxide having a specific surface area of not smaller than 50 m2/g, wherein said composite oxide is capable of maintaining a specific surface area of not smaller than 20 m2/g even after heating at 1100 DEG C. for 6 hours, a method for preparing the same, and a co-catalyst for purifying exhaust gas prepared with the composite oxide.

A powder comprising rare earth element fluoride particles having an aspect ratio of up to 2, an average particle size of 10-100 m, a bulk density of 0.8-1.5 g/cm³, and a carbon content of 0.1-0.5 wt % is amenable to atmospheric plasma spraying. An article obtained by spraying the rare earth fluoride spray powder to a substrate undergoes few partial color changes and performs well even when used in a halogen gas plasma.

The invention discloses a preparation method of a rare-earth-based fluorite type high-entropy oxide powder material and belongs to the field of rare earth oxide powder materials. The method is a low-temperature combustion synthesis method and specifically comprises the following steps: taking rare earth nitride as a metal source and one or a mixture of more of urea, acetic acid, ammonium acetate,oxalic acid and glycine as fuel; and controlling the concentration of metal salt raw materials, types and adding amounts of the fuel, types and adding amounts of a combustion improver and an ignitionmanner to regulate and control properties including granularity, shapes and the like of rare-earth-based fluorite type high-entropy oxide powder. According to the preparation method disclosed by the invention, liquid-phase ingredients are adopted to ensure that a molecular level of the raw materials is uniform and a stoichiometric proportion of a product is realized; meanwhile, the preparation method has the advantages of energy source saving, high production efficiency, greenness and environment protection, no need of complicated post-treatment and the like; and the prepared rare earth oxidepowder has the advantages of high purity, small granularity and uniformity in distribution.

There is disclosed a process of making nano-sized or micro-sized precipitate particles. The process comprising the steps of mixing, in a reaction zone, a metal salt solution with a precipitant solution to form a precipitate, said precipitate being at least one of a metal chalcogenide, metal hydroxide and metal oxide; and applying a shear force to said mixing solutions in said reaction zone during said mixing step, wherein said shear force and the conditions within said reaction zone form said nano-sized or micro-sized precipitate particles.

Provided is a preparation method of a rare earth oxide and graphene nanocomposite material. The method comprises the following steps that 1, an aqueous solution containing needed amount of rare earth nitrate is prepared according to the loading capacity of rare earth oxide on graphene and the preparation quantity of a target product and added into a certain volume of graphene oxide dispersing agent of which the concentration ranges from 0.5 g/L to 5 g/L; 2, an appropriate amount of organic fuel is added into the dispersing agent in the first step, stirring and ultrasound are conducted, and a uniform dispersing agent is obtained; 3, the dispersing agent in the first step is heated and concentrated to be thick, the heated and concentrated dispersing agent is put into a heating furnace of 300 DEG C-900 DEG C for ignition, and after burning is conducted, cooling is conducted to room temperature. The preparation method of the rare earth oxide and graphene nanocomposite material is low in synthesis temperature, short in time, easy to carry out and low in cost, a reducing agent does not need to be additionally added, and graphene oxide is subjected to self reduction to obtain graphene; meanwhile, rare earth oxide is small in particle size and uniform in size, and the uniform dispersibility on graphene is achieved. The preparation method of the rare earth oxide and graphene nanocomposite material is rapid, efficient, high in yield, green, environmentally friendly and suitable for industrial production.

The invention discloses a preparation method of high-specific surface area micro-nano cerium dioxide. The preparation method comprises the steps of preparing a cerium-containing inorganic acid solution, adding an inorganic salt mineralization agent, a surfactant and hydrogen peroxide, stirring to obtain a cerium salt solution, dropwise adding a precipitator solution into the cerium salt solution,stirring at constant temperature to form cerium salt slurry, reacting by virtue of the cerium salt slurry at 80-95 DEG C for 2-24 hours, carrying out centrifugal washing, drying by virtue of a dryingtank, adequately grinding the dried material, and carrying out high-temperature roasting, so as to obtain high-specific surface area micro-nano cerium dioxide. Compared with a traditional hydrothermalmethod, the method disclosed by the invention has the advantages that the reaction temperature is low, the conditions are mild, the operation is easy, prepared micro-nano cerium dioxide is high in specific surface area and small in particle size, and the industrial production is relatively easily realized.

The invention discloses a synthetic method of metallic oxide nanospheres. The synthetic method is characterized by taking microemulsion as a template, hydrolyzing metal alcoholate or organic metal salt in the microemulsion, and finally forming nanospheres. The reaction is capable of introducing matters which can react with each other to generate water into a microemulsion system under an anhydrouscondition, and the water content of the microemulsion system is controlled by controlling the speed of chemical reaction which is capable of generating water, so that effective control on the hydrolysis speed of the metal alcoholate or the organic metal salt can be realized; meanwhile, the micelle diameter of the microemulsion in the microemulsion system can be regulated, and the metallic oxide nanospheres are controllable in particle diameter and narrow in particle diameter distribution; the particle diameter of the metallic oxide nanospheres obtained by utilizing the technology is controllable within a range from 10 to 2000 nm, and the polydispersion index of the particle diameter of the metallic oxide nanospheres ranges from 1 to 5 percent. The synthetic method disclosed by the invention is simple in a synthetic process, easy to operate and good in repeatability and has a good application prospect.