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Firing / sintering of ceramic materials by multiple frequency microwave radiation


Many ceramic materials require a final firing (e.g. earthenware materials such as wall tiles) or sintering (e.g. ferrites process in order to achieve their final properties. From an industrial point of view, the process has not evolved in decades and is still being done in gas furnaces or in electrical ones even though promising new technologies, such as microwaves, are available that can solve many of the problems associated with the conventional process. The project's main goal is to develop a multiple frequency microwave furnace to fire wall tiles and sinter high-tech ferrite components. This two types of materials are chosen for two reasons: i) they have a very different response to microwaves, the former do not absorb well microwaves at low temperatures whereas ferrites are good absorbers and ii) they are used in very important and different European industrial sectors such as the construction sector and the electronics, automotive and telecommunications.Conventional processing of earthenware materials suffers from several drawbacks such as: large thermal inertia, product contamination from fossil fuels, non-uniform temperature profiles, non-homogeneous microstructures reducing mechanical properties and overall quality and fluoride emissions coming from clay-based products during firing. Problems associated with conventional sintering of ferrites are also important: sintering is usually done with inefficient electrical furnaces, rejects are high 5% and sintered microstructures lack homogeneity reducing mechanical and magnetic properties which is particularly important for the high-tech ferrite segment. Although microwave processing has the potential to solve the aforementioned problems, the technical feasibility of this novel processing technique for firing/sintering still needs to be examined for its successful industrial application. A summary of the main goals of the project are: i) Develop and construct a low-cost microwave multiple frequency firing/sintering furnace for processing ceramic materials, designed to work with two superimposed types of magnetrons, of novel design, expected to enhance considerably the electromagnetic field uniformity inside the cavity, ii) Develop novel compositions of wall tiles (frits, glazes and earthenware supports) with a higher degree of microwave absorption, iii) Develop computer tools to study the electromagnetic field and temperature distribution inside the cavity and help in the design of the furnace and iv) Obtain the optimised firing cycle parameters for wall tiles and sintering parameters for ferrites.


Cim - D' or S.A.
11,C/ Riera Roja 11
8830 Sant Boi De Llobregat

Participants (6)

Ceramica San Prospero SpA
136/140,Via Ghiarola Nuova 136/140
41042 Fiorano Modenese
Covimag S.A.
1776,Avenue Du 4 Juillet 1776
19100 Brive La Gaillarde
Ecole Nationale Supérieure de Chimie et de Physique de Bordeaux
Avenue Pey Berland
33405 Talence
Fundación INASMET Asociación de Investigation Metalúrgica del País Vasco
12,Camino De Portuetxe 12
20009 San Sebastián
Kaschke KG GmbH & Co.
6,Rudolf-winkel-strasse 6
37079 Göttingen
Torrecid Sa
Carretera Castellon S/n Apdo18
12110 Alcora Castellon