摘要:
Silicon carbide/silicon nitride composites are prepared by carbothermal reduction of crystalline silica powder, carbon powder and optionally crsytalline silicon nitride powder. The crystalline silicon carbide portion of the composite has a mean number diameter less than about 700 nanometers and contains nitrogen.
摘要:
The present invention generally relates to porous ceramic material and to methods of making and using the material. More particularly, the invention relates to methods of forming ceramic materials by depositing material, using atomic layer deposition, onto a sacrificial substrate and to ceramic materials having controlled wall thickness, relatively large pores, and high surface area by weight.
摘要:
A reactor for conducting vapor phase deposition process is disclosed. The reactor includes a reactive precursor reservoir beneath a powder reservoir and separated from it by valve means. A reactive precursor is charged into the reactive precursor reservoir and a powder is charged into the powder reservoir. The pressures are adjusted so that the pressure in the reactive precursor reservoir is higher than that of the powder reservoir. The valve means is opened, and the vapor phase reactant fluidized the powder and coats its surface. The powder falls into the reactive precursor reservoir. The apparatus permits vapor phase deposition processes to be performed semi-continuously.
摘要:
Ultra-thin porous films are deposited on a substrate in a process that includes laying down an organic polymer, inorganic material or inorganic-organic material via an atomic layer deposition or molecular layer deposition technique, and then treating the resulting film to introduce pores. The films are characterized in having extremely small thicknesses of pores that are typically well less than 50 nm in size.
摘要:
Substrates coated with films of a ceramic material such as aluminum oxides and titanium oxides are biocompatible, and can be used in a variety of applications in which they are implanted in a living body. The substrate is preferably a porous polymer, and may be biodegradable. An important application for the ceramic-coated substrates is as a tissue engineering scaffold for forming artificial tissue.
摘要:
Layers of a passivating material and/or containing luminescent centers are deposited on phosphor particles or particles that contain a host material that is capable of capturing an excitation energy and transferring it to a luminescent center or layer. The layers are formed in an ALD process. The ALD process permits the formation of very thin layers. Coated phosphors have good resistance to ambient moisture and oxygen, and/or can be designed to emit a distribution of desired light wavelengths.
摘要:
Particles have an ultrathin, conformal coating are made using atomic layer deposition methods. The base particles include ceramic and metallic materials. The coatings can also be ceramic or metal materials that can be deposited in a binary reaction sequence. The coated particles are useful as fillers for electronic packaging applications, for making ceramic or cermet parts, as supported catalysts, as well as other applications.
摘要:
The present invention provides an environmentally beneficial process using concentrated sunlight to heat radiation absorbing particles to carry out highly endothermic gas phase chemical reactions ultimately resulting in the production of hydrogen or hydrogen synthesis gases.
摘要:
Prepare silicon nitride-silicon carbide composite powders by carbothermal reduction of crystalline silica powder, carbon powder and, optionally, crystalline silicon nitride powder. The crystalline silicon carbide portion of the composite powders has a mean number diameter less than about 700 nanometers and contains nitrogen. The composite powders may be used to prepare sintered ceramic bodies and self-reinforced silicon nitride ceramic bodies.
摘要:
Methods for carrying out high temperature reactions such as biomass pyrolysis or gasification using solar energy. The biomass particles are rapidly heated in a solar thermal entrainment reactor. The residence time of the particles in the reactor can be 5 seconds or less. The biomass particles may be directly or indirectly heated depending on the reactor design. Metal oxide particles can be fed into the reactor concurrently with the biomass particles, allowing carbothermic reduction of the metal oxide particles by biomass pyrolysis products. The reduced metal oxide particles can be reacted with steam to produce hydrogen in a subsequent process step.