Microwave Processing of Ceramics

Abstract:

Microwave (MW) processing is advantageous for processing ceramics with tailored microstructures. Its combination of volumetric heating, a wide range of controlled heating rates, atmosphere control and the ability to reach very high temperatures allows processing of 'difficult' materials like high thermal conductivity AlN and AlN composites and microstructure control in more readily sintered ceramics such as ZnO. MW sintering promotes development of thermal conductivity in AlN (225 W/mK) and its composites (up to 150W/mK inAlN-TiB2 and up to 129 W/mK in AlN-SiC when solid solution is avoided). In ZnO, heating rate controls sintered grain size. Increasing the heating rate from 5°C/min. to 4900°C decreases grain size from ~10 μm (comparable to conventional sintering of the same powder) to nearly the starting particle size (~ 1μm). Microstructural uniformity increases with sintering rate since ultra-rapid MW sintering minimizes the development of thermal gradients due to heat loss.

• Periodical: Advances in Science and Technology (Volume 45)
• Pages: 857-862
• DOI: https://doi.org/10.4028/www.scientific.net/AST.45.857
• Online since: October 2006
• Authors: Isabel K. Lloyd, Yuval Carmel, Otto C. Wilson Jr., Geng Fu Xu
• Keywords: Aluminum Nitride (AlN), Composite, Microstructure Control, Microwave Processing, Ultra-Rapid, Zinc Oxide (ZnO)

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