Millimeter-Wave Processing of LaCrO3 and LaNiO3 Perovskites Using 28 GHz Frequency

Hirotsugu TAKIZAWA  Masato IWASAKI  

IEICE TRANSACTIONS on Electronics   Vol.E86-C    No.12    pp.2469-2473
Publication Date: 2003/12/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Recent Trends on Microwave and Millimeter Wave Application Technology)
Category: Millimeter-Wave Heating
millimeter-wave processing,  inorganic synthesis,  conductive oxides,  penetration depth,  

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Both Cr2O3 and NiO absorb 28 GHz milli-meter-wave energy well and this strong coupling with millimeter-waves can be used to promote a chemical reaction with La2O3 to form perovskite-type LaCrO3 or LaNiO3 ceramics. In La2O3-Cr2O3 system, the reaction proceeded rapidly and single phase LaCrO3 could be synthesized within 15 min even at lower temperature (400) as compared to conventional synthesis (T > 800). In the case of LaNiO3, the reaction proceeded rapidly in the early stage of heating (t < 15 min), but not completed even after prolonged millimeter-wave irradiation. The results suggest an importance of millimeter-wave penetration depth, especially for processing of conductive materials.