SnO2: A comprehensive review on structures and gas sensors

Combustion of appropriate precursor sprays in a flame spray pyrolysis (FSP) process is a highly promising and versatile technique for the rapid and scalable synthesis of nanostuctural materials with engineered functionalities. The technique was initially derived from the fundamentals of the well-established vapour-fed flame aerosols reactors that was widely practised for the manufacturing of simple commodity powders such as pigmentary titania, fumed silica, alumina, and even optical fibers. In the last 10 years however, FSP knowledge and technology was developed substantially and a wide range of new and complex products have been synthesised, attracting major industries in a diverse field of applications. Key innovations in FSP reactor engineering and precursor chemistry have enabled flexible designs of nanostructured loosely-agglomerated powders and particulate films of pure or mixed oxides and even pure metals and alloys. Unique material morphologies such as core–shell structures and nanorods are possible using this essentially one step and continuous FSP process. Finally, research challenges are discussed and an outlook on the next generation of engineered combustion-made materials is given.

Flame spray pyrolysis: An enabling technology for nanoparticles design and fabrication

Recent advances in aerosol and combustion science and engineering now allow scalable flame synthesis of mixed oxides, metal salts and even pure metals in the form of nanoparticles and films with closely controlled characteristics. In this way, high purity materials with novel metastable phases are made that are not accessible by conventional wet-phase and solid state processes. Here, flame processes are classified into vapour-fed and liquid-fed ones depending on the employed state of the metal precursor. Liquid-fed flame processes are distinguished for their flexibility in producing materials of various compositions and morphologies that result in unique product functionalities. Parameters controlling the characteristics of flame-made particles and films are summarized and selected classes of materials are reviewed focusing on catalysts, sensors, biomaterials (orthopaedic, dental or nutritional), electroceramics (fuel cells, batteries) and phosphors exhibiting superior performance over conventionally made ones. Just a few years ago it seemed impossible to make these materials in the gas phase. Finally, health effects of such particles are discussed while future challenges and opportunities for flame-made materials are highlighted.

Flame aerosol synthesis of smart nanostructured materials

Recent advances in aerosol generation of materials are reviewed Gas-to-particle and spray processes (spray pyrolysis) for powder generation and various routes for film generation are discussed from the experimental and theoretical perspectives The range of materials generated by these routes has increased in recent years to include fullerenes and ceramic superconductors Many metals and various oxide and nonoxide ceramics have also been added to the list of materials generated by gas-phase routes Established aerosol routes such as vapor condensation have found widespread applications for generation of nanophase materials The formation of quantum dots via aerosol approaches has also been demonstrated The theoretical understanding of gas-to-particle conversion routes has advanced to include the finite rate of particle fusion or sintering occurring after collisions of particles The modeling of spray pyrolysis systems has provided insight into the control of particle morphology and reactor design In th

https://www.tandfonline.com/doi/pdf/10.1080/02786829308959650

Aerosol Processing of Materials

A method of enhancing the permeability of a biological membrane, including the skin or mucosa of an animal or the outer layer of a plant to a permeant is described utilizing microporation of selected depth and optionally one or more of sonic, electromagnetic, mechanical and thermal energy and a chemical enhancer. Microporation is accomplished to form a micropore of selected depth in the biological membrane and the porated site is contacted with the permeant. Additional permeation enhancement measures may be applied to the site to enhance both the flux rate of the permeant into the organism through the micropores as well as into targeted tissues within the organism.

Microporation of tissue for delivery of bioactive agents

A new open‐atmosphere chemical vapor deposition (CVD) technique has been developed that we term combustion chemical vapor deposition (CCVD). During CCVD a flame provides the necessary environment for the deposition of a dense film whose elemental constituents are derived from solution, vapor, or gas sources. Ag, YSZ, BaTiO3, YIG, YBa2Cu3Ox, and Y2BaCuO5 have been deposited via CCVD with the combustion of a sprayed, cation‐containing, organic solution as the sole heat source. CCVD could, for some applications, be less expensive and more flexible than conventional CVD.

Combustion chemical vapor deposition: A novel thin‐film deposition technique

A method for applying coatings to substrates using combustion chemical vapor deposition by mixing together a reagent and a carrier solution to form a reagent mixture, igniting the reagent mixture to create a flame, or flowing the reagent mixture through a plasma torch, in which the reagent is at least partially vaporized into a vapor phase, and contacting the vapor phase of the reagent to a substrate resulting in the deposition, at least in part from the vapor phase, of a coating of the reagent which can be controlled so as to have a preferred orientation on the substrate, and an apparatus to accomplish this method.

Combustion chemical vapor deposition of films and coatings

Method for the combustion chemical vapor deposition of films and coatings

A process has been developed that enables the rapid chemical vapor deposition of superconducting YBa2Cu3Ox. In this process a finely ground mixture of Y(tmhd)3, Ba(tmhd)2, and Cu(tmhd)2 (tmhd=2,2,6,6‐tetramethyl‐3,5‐heptanedionate) is slowly fed, and pneumatically transported, directly into the chemical vapor deposition furnace. Because vaporizers are not used, the number of process parameters that must be controlled is greatly reduced. Deposition rates are at least an order of magnitude greater than those achieved by reagent sublimation. Films have been characterized by scanning electron microscopy, energy dispersive x‐ray spectroscopy, x‐ray diffraction, and resistance versus temperature measurements. Films produced on planar MgO substrates have Tc values that are significantly higher than previously reported for MgO.

Rapid chemical vapor deposition of superconducting YBa2Cu3Ox

A method for applying coatings to substrates using chemical vapor deposition with low vapor pressure reagents is disclosed which comprises the steps of: (a) placing a substrate in a furnace means; (b) directly introducing powder reagents by a powder feeder means into said furnace means; and (c) vaporizing and reacting said reagents within said furnace means resulting in the deposition from the vapor phase of a coating on said substrate, wherein said coating can be an oxide superconductor.

William Brent Carter

Papers

Combustion chemical vapor deposition: A novel thin‐film deposition technique

Combustion chemical vapor deposition of films and coatings

Method for the combustion chemical vapor deposition of films and coatings

Rapid chemical vapor deposition of superconducting YBa2Cu3Ox

Method for the rapid deposition with low vapor pressure reactants by chemical vapor deposition