Microwave Fast Sintering of Ceramic Materials

Menezes, Romualdo Rodrigues; Souto, P. M.; Kiminami, R. H. G. A.

doi:10.5772/34181

Cited by 12 publications

(5 citation statements)

References 28 publications

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“…Microwave heating of materials is a process with high rate of heating, based on several heating mechanisms, the most important being the dipole rotation phenomenon. The electromagnetic waves with high frequencies [33] have wavelengths ranging from 1 m to 1 mm being indirect proportionally with frequency. The dipole rotation heating mechanism consists of frictions between dipoles inside materials that change their orientation as function of changing direction of electrical field lines.…”

Section: Introductionmentioning

confidence: 99%

“…State-of-the-art literature, in the field of microwave heating, does not present scientific solutions for protection of the microwave generator antenna. Most of the researches were focused on hybrid microwave heating [10,33] meaning that the samples were introduced in most of the cases into SiC crucibles. Thus, the microwave processing was an indirect one, the samples being heated by thermal radiation accumulated from the silicon carbide crucibles.…”

Section: Introductionmentioning

confidence: 99%

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Composite Polymer for Hybrid Activity Protective Panel in Microwave Generation of Composite Polytetrafluoroethylene -Rapana Thomasiana

et al. 2021

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During the microwave sintering of a polymer-ceramic composite plasma discharge is experienced. The discharge could occur failure of the power source. The solution proposed by the paper is original, no similar solutions being presented by the literature. It consists of using a polymer-ceramic composite protective panel, to stop the plasma discharge to the entrance of the guiding tunnel. Six composites resulted by combining three polymers, Polytetrafluoroethylene (PTFE), STRATITEX composite and Polyvinylchloride (PVC) with two natural ceramics containing calcium carbonate: Rapana Thomasiana (RT) sea-shells and beach sand were used to build the protective panel.Theoretical balance of the power to the panel was analysed and the thermal field was determined. It was applied heating using 0.6-1.2-1.8-2.4-3.0 kW microwave beam power. The panels were subjected to heating with and without material to be sintered. It was analyzed: RT chemical (CaCO3 as Calcite and Aragonite), burned area (range: 200–4000 mm2) and penetration (range: 1.6–5.5 mm), and thermal analysis of the burned areas comparing to the original data. PTFE-RT composite proved the lowest penetration to 0.6 and 1.2 kW. Other 1.2 kW all composites experienced vital failures. Transformation of the polymer matrix of composite consisted of slightly decreasing of the phase shifting temperature and of slightly increasing of the melting start and liquidus temperature.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Composite Polymer for Hybrid Activity Protective Panel in Microwave Generation of Composite Polytetrafluoroethylene -Rapana Thomasiana

et al. 2021

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“…This phenomenon complicates the fabrication of dense materials with nanostructured grains. However, microwave sintering offers an alternative route for the sintering of dense ceramic materials with suppressed grain growth [10]. system.…”

Section: High Frequencies and Permittivity Values Results In Superficial Heating While Low Frequencies And Permittivity Values Results Inmentioning

confidence: 99%

“…Fig.7The microwave hybrid heating arrangement/effect of the susceptor material volume on the final heating pattern[10] …”

mentioning

confidence: 99%

A Review of Microwave-Assisted Sintering Technique

Ćurković

Veseli

Gabelica

et al. 2021

TFAMENA

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The present study examines the potential of microwave heating as an emerging and innovative energy-efficient alternative to conventional heating techniques used for different materials, with a focus on the processing of ceramic materials. Modern ceramics are studied extensively, and their use and different applications are wide due to many advantages of these materials. The most important factor in microwave sintering which differentiates it from conventional heating techniques is a unique heat transfer mechanism. Microwave energy is absorbed by the material, hence the transfer of energy takes place at the molecular level. This way, the heat is generated throughout the material, i.e. on the inside as well on the outside. This allows a very low temperature gradient throughout the material cross section. When conventional sintering is used, typically at high heating rates, high temperature gradients pose a problem. The accelerated microwave heating occurs through the whole volume, so the heating is uniform, which limits the grain growth and coarsening, and leads to a uniform and fine microstructure. The densification is accelerated as well during the unique heat transfer mechanism of microwave sintering, which enhances the mechanical properties of the sintered materials.This paper discusses the use of microwave sintering in the manufacturing of different modern technical materials, namely ceramics, composites, metals and alloys, and glasses. The improvement of different properties is described using the available literature.

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“…An explanation of the low interest shown by industrial manufacturers for the use of microwaves as an energy source in the process of making glass foam could be the theory presented in 1997 in the paper [6], which considers that the commercial glass (soda-lime glass), the main raw material, is poorly microwave susceptible at room temperature due to its high content of transparent microwave materiala (SiO2, Al2O3). The electrical conductivity of the glass and implicitly, the dielectric properties of this material, increase rapidly with increasing the temperature, so that at about 500 ºC the microwave susceptibility reaches a high energy efficiency level [7][8][9]. The theory developed in the paper [6] was taken over in a market study [4], which concluded that the microwave application to the industrial glass foam furnaces would be interesting only for areas with temperatures above 500 ºC, which would mean equipping the furnace with a conventional heating system in the temperature areas below 500 ºC.…”

Section: Introducerementioning

confidence: 99%

Effective microwave heating method for manufacturing glass foam from glass waste

Paunescu¹,

Axinte²,

Drăgoescu³

et al. 2021

RRIC/RJCE

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Rezumat. In lucrare este prezentată o tehnică originală de fabricare a spumei de sticlă prin sinterizarea la temperatură înaltă a deșeului de sticlă datorită încălzirii cu microunde. Încălzirea materiei prime este realizată predominant direct și parțial indirect utilizând un tub ceramic din SiC cu o grosime optimă a peretelui de 2,5 mm. Această metodă contribuie la reducerea semnificativă a consumului specific de energie, a vitezei de incălzire și a duratei procesului comparativ cu tehnicile convenționale de încălzire. Caracteristicile spumei de sticlă sunt similare cu acelea ale spumelor fabricate conventional și pot fi utilizate ca înlocuitori ai materialelor de construcție existente.

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Microwave Fast Sintering of Ceramic Materials

Cited by 12 publications

References 28 publications

Composite Polymer for Hybrid Activity Protective Panel in Microwave Generation of Composite Polytetrafluoroethylene -Rapana Thomasiana

Composite Polymer for Hybrid Activity Protective Panel in Microwave Generation of Composite Polytetrafluoroethylene -Rapana Thomasiana

A Review of Microwave-Assisted Sintering Technique

Effective microwave heating method for manufacturing glass foam from glass waste

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