Abstract:
A method for producing a dense and tenacious coating with a thermal spray gun including a nozzle member and a gas cap. The gas cap extends from the nozzle and has an inwardly facing cylindrical wall defining a combustion chamber with an open end and an opposite end bounded by the nozzle. An annular flow of a combustible mixture is injected at a pressure of at least two bar above atmospheric pressure from the nozzle coaxially into the combustion chamber. An annular outer flow of pressurized air is injected from the nozzle adjacent to the cylindrical wall. Powder particles having a heat-stable, non-fusible component and a heat-softenable component, and entrained in a carrier gas, are fed axially from the nozzle into the combustion chamber. An annular inner flow of pressurized air is injected from the nozzle into the combustion chamber coaxially between the combustible mixture and the powder-carrier gas. Upon combusting the annular mixture a supersonic spray stream containing the powder is propelled through the open end to produce a coating.
Abstract:
Diffusion coatings can be masked from portions of a workpiece by combination of layers the outer one of which forms coherent strong shell that holds inner layer or layers in place. All ingredients of these layers can be materials such as nickel, nickel aluminide, chronium, chromic oxide (Cr.sub.2 O.sub.3) and inert diluent, that do not contaminate superalloys or even low alloy or plain carbon steels. Layer can be deposited from suspension in a solution of film-former like and acrylic resin in readily volatilizable solvent such as methyl chloroform or chloroform. Innermost layer can be depletion-preventing and can be omitted. Such a holding shell can also be used to retain on a workpiece surface a layer that causes formation of a diffusion coating. Chromizing can be performed before aluminizing. Low alloy steel conduit can be internally chromized and/or externally chromized or aluminized to make it more desirable for use as high pressure steam boiler heat exchange tubing. Masking mixtures can be pastes extruded into place. Masking with resin-free masking powder while workpiece is subjected to gas-phase diffusion coating is particularly desirable.
Abstract:
The invention provides a powder coating composition comprising of thermoplastic polymers, ceramic particles, and cermet particles for lowering the friction coefficient, and improving wear and corrosion resistance of coated surfaces in high-temperature, high-pressure, and corrosive environments. It also provides a method of coating application for improving adhesion of the coating to the substrate. The coating compositions are devoid of volatile organic solvents and can be applied on surfaces using thermal spraying, compression molding and other particle sintering approaches. A multilayer architecture consisting of an adhesive bottom layer and a non-adhesive, low friction top layer is disclosed. The coating can be used in oil and gas production and seawater injection.
Abstract:
The method for flame spraying thermoplastic powders provides to heat the article to be coated at a suitable working temperature and to feed the said thermoplastic powders transported by an inert gas through inlet (4), a flow of compressed air or nitrogen through inlet (5) and a flow of liquefied petroleum gas through inlet (6), then through respective separated discharge chambers (7, 9, 12) shaped inside a mixing device (1) of a spray gun. The thermoplastic powders are then projected, in a resulting flow (30), on the heated surface of the article to be coated, to determine the melting of the same powders at their contact with said heated surface. At least one couple of flows (31, 32) of compressed air is sprayed converging towards the resulting flow (30) flowing out of the mixing device (1), giving the resulting flow (30) a substantially flattened fan shape. The converging flows (31,32) of compressed air are sprayed by inclined passageways (17,18) located between a first ring of compressed air nozzles (13) and an outside ring of fuel nozzles (14).
Abstract:
The invention relates to a fitting, item of furniture, and/or large household appliance constructed of metal components, wherein the metal component comprises a coating at least in sections, comprising at least one perfluoralkoxy-copolymer (PFA), to a method for the production thereof, and to a fitting, an item of furniture, and/or a large household appliance.
Abstract:
A particle for depositing a coating on a substrate surface by a low temperature thermal spray process having a plastic core and a particulate forming an non- continuous cladding layer around the plastic core so that enough heat can be transferred to the plastic core to cause it to melt but not so much so as to vaporize the plastic core. At the same time the particulate cladding material having a higher melting point does not melt. A particle having an inorganic core clad to a plastic outer layer is also provided. A process for making the clad material and for thermally spraying the clad material is provided. An article coated with the clad material is also provided.