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Laser-Assisted Microwave Plasma Processing of Ceramic Coatings
M. Willert-Porada, P. Pontiller, H.-S. Park, A. Rosin
University of Bayreuth, Chair of Materials Processing, 95447 Bayreuth, Universitätsstr. 30, Germany
received March 4, 2013, received in revised form March 25, 2013, accepted April 4, 2013
Vol. 4, No. 1, Pages 1-10 DOI: 10.4416/JCST2013-00003
Abstract
The aim of Laser-Assisted Microwave Plasma Processing of materials, abbreviated as LAMPP, is to utilize a spatially well-confined laser beam to ignite and localize a microwave plasma plume as an energy source for the sintering, melting or recrystallization of ceramic coatings. The energy required for the high-temperature treatment is supplied to a significant extent from the microwave source that feeds the plasma while the laser beam is used to scan the microwave plasma over the surface area to be treated. The phenomena underlying ignition and sustainment of the plasma are described in respect of the two possible ignition mechanisms: Laser-Induced Breakdown, LIB, or Microwave-Induced Breakdown, MIB. The influence of the material to be processed on prevalence of one of these ignition mechanisms is discussed. Examples of equipment built in our laboratory to enable LAMPP in different atmospheres for different substrates and coatings are shown. As potential applications of LAMPP, re-melting of ceramic plasma-sprayed thermal barrier coatings and melting of non-stabilized ZrO2 ceramic for coating purposes are presented.
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Keywords
Microwave plasma, ceramic melt processing, LIB, MIB
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