Abstract:
A powder batch is described comprising single crystal metal-containing particles having a crystal size of less than 50nm as measured by X-ray diffraction and having a weight average particle size of from about 10 nanometers to less than 100 nanometers as measured by transmission electron microscopy and including a continuous or non-continuous coating of a ceramic material. The powder batch is preferably produced by flame spraying.
Abstract:
In one aspect, the process includes providing a precursor medium comprising a liquid vehicle and a precursor to a component, and flame spraying the precursor medium under conditions effective to form a population of nanoparticles, wherein the nanoparticles include the component. The population of nanoparticles, as formed, comprises less than about 5 percent by volume particles having a particle size greater than 1.0 µm. A size distribution of the population of nanoparticles may have a d50 value less than about 500 nm, and it may be unimodal. The size distribution may have a geometric standard deviation of less than about 2. The process may occur continuously for at least four hours or more. Greater than about 90 percent by weight of the precursor to the component in the precursor medium may be converted to the component in the nanoparticles. The process typically occurs in an enclosed flame spray reactor.
Abstract:
Security features, e.g., reflective security features, and processes for forming security features are described. The security features comprise crystalline metal-containing particles having a primary particle size of from about 10 nanometers to less than 500 nanometers and including a continuous or non-continuous coating of a ceramic material. Inks comprising such crystalline metal-containing particles are also described. The crystalline metal-containing particles are preferably produced by flame spraying.
Abstract:
The invention relates to a process for decreasing flame temperature in a flame spray reaction system, the process comprising the steps of providing a precursor medium comprising a precursor to a component; flame spraying the precursor medium under conditions effective to form a population of product particles; and decreasing the flame temperature by contacting the flame with a cooling medium. The process of the present invention allows for the control of the size, composition and morphology of the nanoparticles made using the process. The invention also relates to a nozzle assembly that comprises a substantially longitudinally extending atomizing feed nozzle that comprises an atomizing medium conduit and one or more substantially longitudinally extending precursor medium feed conduits. The nozzle assembly of the present invention is used in a flame spray system to produce nanoparticles using the processes described herein.
Abstract:
Photovoltaic conductive features and processes for forming photovoltaic conductive features are described. The process comprises (a) depositing a composition onto at least a portion of a substrate, wherein the composition comprises metal-containing particles having a primary particle size of from about 10 nanometers to less than 500 nanometers and including a continuous or non-continuous coating of a ceramic material; and (b) heating the composition such that the precursor composition forms at least a portion of a photovoltaic conductive feature. The metal-containing particles are preferably produced by flame spraying.
Abstract:
A powder batch is described comprising single crystal metal-containing particles having a crystal size of less than 50nm as measured by X-ray diffraction and having a weight average particle size of from about 10 nanometers to less than 100 nanometers as measured by transmission electron microscopy and including a continuous or non-continuous coating of a ceramic material. The powder batch is preferably produced by flame spraying.
Abstract:
In one aspect, the process includes providing a precursor medium comprising a liquid vehicle and a precursor to a component, and flame spraying the precursor medium under conditions effective to form a population of nanoparticles, wherein the nanoparticles include the component. The population of nanoparticles, as formed, comprises less than about 5 percent by volume particles having a particle size greater than 1.0 µm. A size distribution of the population of nanoparticles may have a d50 value less than about 500 nm, and it may be unimodal. The size distribution may have a geometric standard deviation of less than about 2. The process may occur continuously for at least four hours or more. Greater than about 90 percent by weight of the precursor to the component in the precursor medium may be converted to the component in the nanoparticles. The process typically occurs in an enclosed flame spray reactor.
Abstract:
The invention provides a process for the production of fumed silica. The process comprises providing a silicon halide feedstock comprising about 80% to 100% methyltrichlorosilane, combining the silicon halide feedstock with hydrogen gas and oxygen gas to form a reactant mixture, discharging the reactant mixture out of a burner, and combusting the hydrogen gas and the oxygen gas of the reactant mixture so as to hydrolyze the silicon halide feedstock to produce fumed silica. Hydrogen (H2) is present in a mole fraction of about 0.11 or less based on the reactant mixture, and/or the velocity of the reactant mixture upon exiting the burner is about 25 m/s or more.
Abstract:
The invention provides a process for the production of fumed silica. The process comprises providing a silicon halide feedstock comprising about 80% to 100% methyltrichlorosilane, combining the silicon halide feedstock with hydrogen gas and oxygen gas to form a reactant mixture, discharging the reactant mixture out of a burner, and combusting the hydrogen gas and the oxygen gas of the reactant mixture so as to hydrolyze the silicon halide feedstock to produce fumed silica. Hydrogen (H 2 ) is present in a mole fraction of about 0.11 or less based on the reactant mixture, and/or the velocity of the reactant mixture upon exiting the burner is about 25 m/s or more.
Abstract:
Security features, e.g., reflective security features, and processes for forming security features are described. The security features comprise crystalline metal-containing particles having a primary particle size of from about 10 nanometers to less than 500 nanometers and including a continuous or non-continuous coating of a ceramic material. Inks comprising such crystalline metal-containing particles are also described. The crystalline metal-containing particles are preferably produced by flame spraying.