Cold gas spraying

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Scanning electron microscope image of a titanium particle on a steel surface
Information from the USAF on the Cold Spray Process

The cold gas spraying (English: Cold Spray ) (CS) is a coating method in which the coating material in powder form at a very high speed to the carrier material ( substrate is applied). For this purpose, a process gas (nitrogen or helium) heated to a few hundred degrees is accelerated to supersonic speed by expansion in a Laval nozzle and then the powder particles are injected into the gas jet. The injected spray particles are accelerated to such a high speed that, in contrast to other thermal spray processes, they form a dense and firmly adhering layer when they hit the substrate, even without prior melting or melting. The kinetic energy at the time of impact is insufficient for the particles to melt completely. Cold gas spraying emerged from high-speed flame spraying (HVOF).

Cold gas spraying was developed at the Institute for Theoretical and Applied Mechanics of the Siberian Department of the Russian Academy of Sciences in Novosibirsk and a patent was applied for in 1986 in the Soviet Union . It is still being followed up there today. One of the scientists working there, Anatoli Papyrin, applied for the patent in the USA in 1994 and began to work on the further industrialization of the process with the US consortium National Center for Manufacturing Science (NCMS) based in Ann Arbor . The consortium includes a. The following companies are involved: Alcoa, ASB Industries, Ford, K-Tech, Pratt & Whitney, Siemens Westinghouse and Sandia National Lab. In Germany, the process was patented in 1995 and further development was u. a. promoted by Linde AG together with the Helmut Schmidt University / University of the Federal Armed Forces Hamburg . The company CGT Cold Gas Technology GmbH was founded for the construction and marketing of cold gas spray systems. According to information from the company, Papyrin transferred its basic patent to them in 2006.

Cold gas spraying is used industrially today in the automotive industry; new fields are gradually emerging, such as in the area of ​​tool repair and tool construction ( rapid manufacturing ) and in the area of ​​microtechnology.

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