A method for making rare earth metal oxide ceramic precursor composition comprising reacting a rare earth metal alkoxide with a complexing agent to give a mixture of complexing agent/alkoxide rare earth metal complexes is disclosed. The mixture is hydrolyzed and the precursor composition is isolated. Solubility of the precursor composition in non-polar or polar solvents is affected by the selection of complexing agent amongst other factors. At least partial dissolution of the precursor composition in a solvent gives a preceramic liquid which upon evaporation of the solvent and heating gives a rare earth metal oxide ceramic. Utility of the preceramic liquid include the formation of rare earth metal oxide fibers, thin films, coatings, foams, powders, cast or molded objects or it may be used as a ceramic adhesive.
A method for making very strong gas mantles and other ceramic structures, and the resulting products, are provided. According to the method, an organic or composite structure is first pyrolyzed in the absence of oxygen to remove hydrogen, oxygen and nitrogen, leaving a porous carbon or composite structure, which is then impregnated with a metal compound-containing solution or slurry which is later fired in the presence of an oxidizing atmosphere to produce a refractory metal oxide which has about the same shape as the precursor carbon or composite structure. Due to minimal shrinkage of the mostly carbon or composite precursor, the resulting mantles and other ceramic structures have few defects in the fibers and great strength.
A heat-resistant coated member comprises a substrate composed of a material selected from among molybdenum, tantalum, tungsten, zirconium, aluminum, titanium, carbon, and alloys, oxide ceramics, non-oxide ceramics and carbide materials thereof, which is covered with a layer composed primarily of a rare earth-containing oxide. In addition to heat resistance, the coated member has good corrosion resistance and non-reactivity, making it highly suitable as a part for sintering or heat-treating metals and ceramics in a vacuum, an inert atmosphere or a reducing atmosphere.
A superemissive combustion device of this invention comprises a porous distributive layer and an apparatus for delivering a fuel/oxidizer mixture to an upstream face of the porous distributive layer. A superemissive advanced emissive matrix in is disposed within an active flame zone downstream from the porous distributive layer. The emissive matrix is in the form of a three dimensional matrix of radiating bodies that is optically thin to electromagnetic radiation. The emissive matrix is either formed from or includes a coating of a superemissive material that is selected to emit photons within a predetermined wavelength range when thermally stimulated. The emitted photons are received by one or more photovoltaic cells disposed adjacent the matrix.
A heat-resistant coated member comprises a substrate composed of a material selected from among molybdenum, tantalum, tungsten, zirconium, aluminum, titanium, carbon, and alloys, oxide ceramics, non-oxide ceramics and carbide materials thereof, which is covered with a layer composed primarily of a rare earth-containing oxide. In addition to heat resistance, the coated member has good corrosion resistance and non-reactivity, making it highly suitable as a part for sintering or heat-treating metals and ceramics in a vacuum, an inert atmosphere or a reducing atmosphere.
The present invention provides an apparatus and method for determining the concentration of CO gas in a fuel reformate stream such as in a PEM fuel cell vehicle. This invention protects the fuel cell catalyst by controlling the reformate stream system to minimize the CO and reduce it by a novel catalyst system that selectively converts CO to methane but does not react with carbon dioxide and hydrogen. The catalyst may reduce the CO to methane by reaction with hydrogen. The preferred embodiment both monitors the CO by a thermal differential sensing means and an optical biomimetic sensor and or a conductivity sensor. These sensors respond to the CO gas and are monitored by one or more monitoring sensors such as the temperature and or conductivity difference between the control and the catalytic material such as nickel and in the biomimetic sensor an optical change is monitored. The optical sensing comprising a photon source optically coupled to the sensor and photodiode system, so that the photon flux is a function of at least one other sensor's response to the CO gas, e.g., transmits light through the sensor to the photodiode. The photocurrent from the photodiode is converted to a digital sensor reading value proportional to the optical characteristic(s) of the sensor(s) as a function of time and the data is loaded into a microprocessor or other logic circuit. In the microprocessor, the sensor readings are essentially used to calculate the CO concentration and control the process to maximize the fuel cell or to trigger a signal for service.
