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Title: Solid-state synthesis of YAG powders through microwave coupling of oxide/carbon particulate mixtures

The rapid synthesis of yttrium aluminum garnet (Y 3Al 15O 12, YAG) powder was investigated through the use of microwave irradiation of the oxide precursor system. For this investigation, an external hybrid heating source was not used. Instead, the rapid heating of the precursor materials (yttria and alumina powders, which are typically transparent to 2.45 GHz microwaves) was initiated by mixing an intrinsic absorbing material (carbon) into the original oxide precursors. The effect of the carbon characteristics, such as carbon source, concentration, particle size, and agglomerate microstructure were evaluated on the efficiency of coupling and resultant oxide reaction. The microwave power was varied to optimize the YAG conversion and eliminate intermediate phase formation. Interactions between the conductive carbon particles and the dielectric oxides within the microwave exposure produced local arching and micro-plasma formation within the powder bed, resulting in the rapid formation of the refractory YAG composition. This optimal conduction led to temperatures of 1000°C that could be achieved in less than 5 min resulting in the formation of > 90 vol% YAG. The understanding of a conductor/dielectric particulate system here, provided insight into possible application of similar systems where microwave irradiation could be used for enhanced solid-state formation, localmore » melting events, and gas phase reactions with a composite powder media.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3]
  1. National Energy Technology Lab. (NETL), Morgantown, WV (United States); Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States)
  2. West Virginia Univ., Morgantown, WV (United States)
  3. National Energy Technology Lab. (NETL), Morgantown, WV (United States)
Publication Date:
Report Number(s):
NETL-PUB-21486
Journal ID: ISSN 0272-8842; PII: S0272884217312221
Type:
Accepted Manuscript
Journal Name:
Ceramics International
Additional Journal Information:
Journal Volume: 43; Journal Issue: 14; Journal ID: ISSN 0272-8842
Publisher:
Elsevier
Research Org:
National Energy Technology Lab. (NETL), Pittsburgh, PA, and Morgantown, WV (United States); Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Fossil Energy (FE)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; Microwave processing; Yttria aluminum garnet (YAG); Carbon; Solid state reaction
OSTI Identifier:
1440334