Plasma particle technology

One key focus at the Application Center for Plasma and Photonics of the Fraunhofer Institute for Surface Engineering and Thin Films IST in Göttingen is plasma particle technology. The work here concentrates on the generation or modification of particles and on plasma coating with processing of ultra-fine powders. 

The technological basis of the plasma particle technology is predominantly the systems and processes developed at the Application Center. These include:

• Arc-discharge source for the synthesis of carbon nanoparticles
• Atmospheric pressure sputter jet for the synthesis of nanoparticles and for producing coatings
• Low-pressure sputtering system for the all-round coating of micro- and nano-powders
• Plasma reactor for functionalizing powders
• Plasma jet with liquid feeder for processing solutions and dispersions for coating purposes
• Plasma jet with powder delivery system for the secure use of particles for creating coatings

A wide range of materials can be created and processed with the systems available. The spectrum extends from metals via metal oxides, ceramics, and composites to polymer powders. 

In addition, the plasma particle technology includes the coating and finishing of objects of the most varied types and geometries – from the thinnest films to complex, three-dimensional structures. 

Our offer

• Individual solution concepts
• Feasibility studies
• Prototype production
• Technology transfer
• Advice on the implementation of new product options

At the Application Center micro- and nano-particles on the one hand are produced by sputtering various metals with an atmospheric pressure sputter jet. On the other hand, carbon particles are produced by the sublimation of graphite rods in an arc discharge source. The particles can be deposited either directly as nanoclusters on different surfaces or captured for further processing or modification.

Equipping micro- and nano-particles with specific properties involves treating them with plasma at atmospheric or low pressure. Here, the particle surfaces are equipped with functional groups or coatings and their optical, electrical, magnetic or chemical properties are modified selectivley. By functionalizing the surface of particles of precious metals such as gold, it is possible, for example, to optimize wettability by liquids and thus produce stable aqueous dispersions. Furthermore, a coating can improve the flowability and separability of the particles by minimizing not only the mutual cohesion of the individual particles but also their unwanted adhesion to surfaces. This creates the conditions for an optimum processability of particles which are used for plasma spraying processes and in particular in the innovative cold plasma spraying. 

Application example: function particles for electrical metrology

In measuring the electrical resistance of objects with a rough surface, such as the electrodes of lithium-ion batteries, it is often impossible to achieve a low-impedance, non-destructive and yet stable contact. Modified particles offer a solution here, and make a reliable acquisition of measured data possible. To measure resistances in, for example, thin battery electrode layers, a new “powder probe” and a measuring set-up were developed at the Application Center. Key components are magnetizable micro particles which are given a highly electrically conductive coating made of silver. By means of a carrier magnet, the particles form a three-dimensional shape with antenna-like structures which locks positively even into complex surface structures and ensures an excellent contact.

Our offer

• Plasma-based particle generation of Au, Ag, Cu, Wo, C, for example
• Plasma coating of particles with carbon and metals such as Ag, Ti, TiN, Al, Cu and Zn
• Functionalization of particle surfaces

To process the produced and modified particles, the Application Center uses the so called cold plasma spraying. The use of a cold-regulated plasma jet makes this possible.

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