The number of research papers as well as of patents and patent applications on cold spray and cold spray related technologies has grown exponentially in the current decade. This rapid growth of activity brought a tremendous amount of information on this technology in a short period of time. The main motivation for this review is to summarize the rapidly expanding common knowledge on cold spray to help researchers and engineers already or soon to be involved for their future endeavors with this new technology. Cold spray is one of the various names for describing an all-solid-state coating process that uses a high-speed gas jet to accelerate powder particles toward a substrate where they plastically deform and consolidate upon impact. Cold gas dynamic spray, cold spray, kinetic spray, supersonic particle deposition, dynamic metallization or kinetic metallization are all terminologies found in the literature that designate the above-defined coating process. This review on cold spray technology is divided into two parts. In this article, Part I, patents and patent applications related to this process are reviewed, starting from the first few mentions of the idea at the beginning of the 20th century to its practical discovery in Russia in the 1980s and its subsequent occidental development and commercialization. The patent review encompasses Russian and USA patents and patent applications. Part II will review the scientific literature giving a general perspective of the current understanding and capability of this process.

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Review on Cold Spray Process and Technology: Part I—Intellectual Property

The invention relates to an apparatus and process for solid-state deposition and consolidation of powder particles entrained in a subsonic or sonic gas jet onto the surface of an object. Under high velocity impact and thermal plastic deformation, the powder particles adhesively bond to the substrate and cohesively bond together to form consolidated materials with metallurgical bonds. The powder particles and optionally the surface of the object are heated to a temperature that reduces yield strength and permits plastic deformation at low flow stress levels during high velocity impact, but which is not so high as to melt the powder particles.

System and process for solid-state deposition and consolidation of high velocity powder particles using thermal plastic deformation

Apparatus and methods are provided for converting methane in a feed stream to acetylene. A hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process.

Methane conversion apparatus and process using a supersonic flow reactor

A method for manufacturing a hermetically sealed micro-device package encapsulating a micro-device. The package includes a transparent window allowing light to pass into and out of a cavity containing the micro-device. A first frame-attachment area is prepared on semiconductor substrate having a micro-device operably disposed thereupon, the first frame-attachment area having a plan that circumscribes the micro-device. A second frame-attachment area is prepared on a sheet of transparent material, the second frame-attachment area having a plan that circumscribes a window aperture portion of the sheet. A frame/spacer is positioned between the semiconductor substrate and the sheet, the frame/spacer including a continuous sidewall having a plan on one side substantially corresponding to, and substantially in register with, the plan of the first frame-attachment area, having a plan on the opposite side substantially corresponding to, and substantially in register with, the plan of the second frame-attachment area, and having a height that exceeds the height of the micro-device. Next the substrate, frame/spacer and window are bonded together to form a hermetically sealed package encapsulating the micro-device in a cavity below the window aperture portion of the transparent sheet.

Wafer-level hermetic micro-device packages

A bioerodible endoprosthesis erodes by galvanic erosion that can provide, e.g., improved endothelialization and therapeutic effects.

Bioerodible endoprostheses and methods of making the same

A method and apparatus is disclosed for kinetic spray coating of substrate surfaces by impingement of air or gas entrained powders of small particles in a range up to at least 106 microns accelerated to supersonic velocity in a spray nozzle. Preferably powders of metals, alloys, polymers and mixtures thereof or with semiconductors or ceramics are entrained in unheated air and passed through an injection tube into a larger flow of heated air for mixing and acceleration through a supersonic nozzle for coating of an article by impingement of the yieldable particles. A preferred apparatus includes a high pressure air supply carrying entrained particles exceeding 50 microns through an injection tube into heated air in a mixing chamber for mixing and acceleration in the nozzle. The mixing chamber is supplied with high pressure heated air through a main air passage having an area ratio relative to the injection tube of at least 80/1.

Kinetic spray coating method and apparatus

Electroplated chromium coatings on automobile suspension damper piston rods are replaced with thermal or kinetic spray coatings of: (a) suitable corrosion-resistant metal alloys such as iron and chromium containing nickel-based alloys or chromium containing steels, or (b) suitable ceramic coatings such as electrically insulative alumina ceramics. The spray coatings are porous, and the metal alloy coatings usually should be sealed for corrosion protection.

Spray coatings for suspension damper rods

An apparatus is disclosed for kinetic spray coating of substrate surfaces by impingement of air or gas entrained powders of small particles in a range up to at least 106 microns accelerated to supersonic velocity in a spray nozzle. Preferably powders of metals, alloys, polymers and mixtures thereof or with semiconductors or ceramics are entrained in unheated air and passed through an injection tube into a larger flow of heated air for mixing and acceleration through a supersonic nozzle for coating of an article by impingement of the yieldable particles. A preferred apparatus includes a high pressure air supply carrying entrained particles exceeding 50 microns through an injection tube into heated air in a mixing chamber for mixing and acceleration in the nozzle. The mixing chamber is supplied with high pressure heated air through a main air passage having an area ratio relative to the injection tube of at least 80/1.

Kinetic spray coating apparatus

A converging diverging supersonic nozzle for a kinetic spray system is disclosed. In one embodiment, the supersonic nozzle has a first end opposite an exit end and a diverging region adjacent the exit end. A removable throat insert has an entrance cone and a throat and is received in the first end with the throat positioned adjacent the diverging region. In another embodiment, the removable throat insert has an entrance cone, a diverging region and a throat positioned between the entrance cone and the diverging region. The disclosed replaceable throat inserts address the problem of excessive wear in the throat relative to the rest of the supersonic nozzle which has plagued other kinetic spray systems. With the disclosed inserts a worn throat can rapidly and economically be replaced while saving the rest of the supersonic nozzle.

Replaceable throat insert for a kinetic spray nozzle

A method is disclosed for direct application of a brazing flux material to a brazing surface. The method includes the step of applying a brazing filler material to a substrate utilizing a kinetic spray process to form a brazing surface. Following application of the brazing filler material to the substrate brazing flux material can be directly applied to the brazing surface as either a dry powder or a wet slurry. The nature of the brazing surface allows the applied flux material to adhere to the surface without the utilization of additional binders or resin materials.

Steenkiste Thomas H. Van

Papers

Kinetic spray coating method and apparatus

Spray coatings for suspension damper rods

Kinetic spray coating apparatus

Replaceable throat insert for a kinetic spray nozzle

Method for direct application of flux to a brazing surface