Next Article in Journal
Comparative Study of Electrophoretic Deposition of Doped BaCeO3-Based Films on La2NiO4+δ and La1.7Ba0.3NiO4+δ Cathode Substrates
Previous Article in Journal
Research on the Influence of Bed Joint Reinforcement on Strength and Deformability of Masonry Shear Walls
Previous Article in Special Issue
Microwave Sintering of SiAlON Ceramics with TiN Addition
Article Menu

Export Article

Open AccessFeature PaperArticle

Microwave Sintering of Alumina at 915 MHz: Modeling, Process Control, and Microstructure Distribution

Normandie Univ, ENSICAEN, UNICAEN, CNRS, CRISMAT, 14000 Caen, France
Laboratoire Georges Friedel, École des Mines de Saint-Étienne, 42023 Saint-Etienne, France
SOLCERA, ZI n 1 Rue de l’industrie, 27000 Evreux, France
DGA (Direction Générale de l’Armement), Echangeur de Guerry, 18000 Bourges, France
Author to whom correspondence should be addressed.
Materials 2019, 12(16), 2544;
Received: 3 July 2019 / Revised: 2 August 2019 / Accepted: 7 August 2019 / Published: 9 August 2019
(This article belongs to the Special Issue Conventional and Microwave Sintering Techniques in Materials)
PDF [4540 KB, uploaded 9 August 2019]


Microwave energy can be advantageously used for materials processing as it provides high heating rates and homogeneous temperature field distribution. These features are partly due to the large microwave penetration depth into dielectric materials which is, at room temperature, a few centimeters in most dielectric materials. However, up to now, this technology is not widely spread for high-temperature material processing applications (>1200 °C), because its reproducibly and ability to sinter large size samples (>30 cm3) still needs to be improved. In this context, this paper describes both an empirically designed 915 MHz single-mode cavity made from SiC susceptors and refractory thermal insulation, and the 3D modeling of the process in order to improve our understanding of it. Different susceptors geometries and coupling slit position were numerically tested in order to better understand how these parameters impact the field homogeneity and the process stability. It was found that positioning the largest surface of the susceptors parallel to the electrical field allows a very uniform and hybrid heating of the material, while avoiding plasma or thermal instabilities. This was correlated to the 3D modeling results. Finally, thanks to a fully-automatized system this apparatus was used to sinter large size (~30 cm3) low-loss dielectric alumina samples. The sintered materials were subsequently characterized in terms of density, grain size distribution, and homogeneity. The reproducibility was also discussed, demonstrating the process efficiency and reliability. View Full-Text
Keywords: microwave sintering; resonant applicator; process control; alumina; hybrid heating; modeling microwave sintering; resonant applicator; process control; alumina; hybrid heating; modeling

Graphical abstract

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Marinel, S.; Manière, C.; Bilot, A.; Bilot, C.; Harnois, C.; Riquet, G.; Valdivieso, F.; Meunier, C.; Coureau, C.; Barthélemy, F. Microwave Sintering of Alumina at 915 MHz: Modeling, Process Control, and Microstructure Distribution. Materials 2019, 12, 2544.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Materials EISSN 1996-1944 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top