Microwave Pyrolysis of Emulsified Ceramic Precursor Compounds

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Willert-Porada, Monika ; Dennhöfer, S. ; Hachmeister, D.:
Microwave Pyrolysis of Emulsified Ceramic Precursor Compounds.
In: MRS Online Proceedings Library. Bd. 347 (1994) . - S. 571-577.
ISSN 1946-4274
DOI: https://doi.org/10.1557/PROC-347-571

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Abstract

Application of paraffin as a MW-transparent matrix for microwave pyrolysis of metalorganic compounds enables synthesis of large quantities of nanosized powders with excellent storability and packing behavior. Fully crystalline, nanosized t-ZrO₂ powders with specific surface area > 200 m²g⁻¹ are obtained from Zr-alcoholate, and alumina powders with > 500 m²g⁻¹ from Al-alcoholates. Some differences exist between microwave pyrolysis and conventional pyrolysis of such mixtures. Powders from microwave pyrolysis transform at lower calcination temperature to α-A1₂O₃ and exhibit after calcination a more homogeneous morphology as compared to powders from conventional pyrolysis. Furthermore, a different composition of the volatile pyrolysis products is found. t-ZrO₂ powder from the microwave processing route exhibits an increased stability towards transformation to monoclinic ZrO₂ as well as smaller initial grain sizes than a conventionally synthesized powder.