Structural and Microwave Properties of Silica Xerogel Glass-Ceramic Sintered by Sub-millimeter Wave Heating using a Gyrotron

Aripin, H.; Mitsudo, S.; Prima, Endangsusilowati S.; Sudiana, I Nyoman; Tani, S.; Sako, K.; Fujii, Yutaka; Saito, T.; Idehara, T.; Sano, Saburo; Sunendar, Bambang; Sabchevski, S.

doi:10.1007/s10762-012-9925-7

Cited by 19 publications

(10 citation statements)

References 31 publications

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“…Therefore, SiO 2 production from these sources on an industrial scale is not technologically or economically viable. In our study, SiO 2 in the form of silica xerogel was prepared using a sago waste ash (Aripin et al, 2011;Aripin et al, 2012) as a starting powder and was used to produce TiO 2 -SiO 2 composites by mixing 20 wt% and 40 wt% of TiO 2 into SiO 2 . It was found that, at 900°C, the size of the anatase crystallites are 26.3 nm and 21.4 nm for 20 wt% and 40 wt% of TiO 2 , respectively.…”

Section: Introductionmentioning

confidence: 99%

Formation and Particle Growth of TiO2 in Silica Xerogel Glass Ceramic During a Sintering Process

Aripin¹,

Made²,

Mitsudo³

et al. 2017

IJTech

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This investigation presents the synthesis procedure and the results of an investigation of the crystallite growth of TiO 2 and the formation of Si-O-Ti bonds in novel silica xerogel (SiO 2 ) glass ceramic produced from an amorphous SX derived from sago waste ash. The composition had been prepared by adding various amounts of TiO 2 , from 20 wt% to 80 wt%, into the amorphous SiO 2 , and then a series of samples were sintered at 1200°C for 2 hours. The influence of the content of TiO 2 and the sintering temperature on the properties of TiO 2 , namely crystallite size and formation of Si-O-Ti bonds, has been studied in detail. The properties of the produced ceramics have been characterized on the basis of the experimental data obtained using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. It has been found that an addition of SiO 2 confers an appreciable effect on the quantity of Si-O-Ti bonds. The interpretation of the XRD pattern allows one to explain the increase in the crystallite size of rutile TiO 2 by a decreased quantity of Si-O-Ti bonds.

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Section: Introductionmentioning

confidence: 99%

Formation and Particle Growth of TiO2 in Silica Xerogel Glass Ceramic During a Sintering Process

Aripin¹,

Made²,

Mitsudo³

et al. 2017

IJTech

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show abstract

“…These characteristics make it possible to become a good alternative candidate of microwave absorbing material. The study of this material for microwave absorber as well as alumina as ceramic materials are performed by our group research [7][8][9][10][11][12][13]. The silica was extracted from various agricultural wastes.…”

Section: Introductionmentioning

confidence: 99%

Investigation of silica from rice husk ash wastes as an alternative material for microwave absorbers

Sudiana¹,

Mitsudo²,

Firihu³

et al. 2017

AIP Conference Proceedings

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Abstract. An attempt was made to produce silica from an agricultural waste, i.e. rice husk ash (RHA), for a microwave absorber. The high percentage of silica content from RHA was used as a silica source for sodium silica solutions. Different heating temperatures, times and acid treatments were studied for silica extractions. The composite was characterized and its microwave properties were investigated after sintering from 400 to 1200 o C. The results showed that the existing phases in all compositions at 1200 o C were mullite, cristobalite and Al2O3 . The intensities of cristobalite peaks gradually decreased with increased compositions of Al 2 O 3 , while the intensities of mullite peaks increased with the increased compositions of Al 2 O 3 . Compositions with higher amounts of amorphous silica xerogel showed a lower degree of Al 2 O 3 peaks when compared to other compositions, while the peaks of cristobalite were found to be with greater intensities. A correlation between the structural changes and the microwave properties of the samples in frequencies ranging from 8.2 to 12.4 GHz has been found and discussed. The calculated values showed that the reflection losses decreased as the sintering temperatures were increased up to 1200 °C. The increasing degree of crystallinity was identified as the main reason for the decrease of the reflection losses since the silica xerogel glass ceramic becomes more transparent to microwaves.

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“…Moreover, a very high frequency microwave processing system within a range of sub-millimeter waves with a frequency of 300 GHz has been developed at FIR Center [4]. This device has been successfully used for sintering alumina, zirconia, and silica [5][6][7][8]. Researchers believe that the use of higher frequencies possesses greater microwave effects and the existing problems found in lower frequencies would be more easily solved.…”

Section: Introductionmentioning

confidence: 99%

“…Those enhancements are grouped into two. The first enhancement consists of indirect evidence of diffusion such as observations of enhanced sintering, grain growth, or reaction zones [3,[5][6][7][8][9][10]. This type of observations does not provide clear evidence of enhanced diffusion due to its difficult in interpretation for complex processes such as sintering, grain growth, phase change, and chemical reaction.…”

Section: Introductionmentioning

confidence: 99%

Microwaves enhanced sintering mechanisms in alumina ceramic sintering experiments

Firihu¹,

Sudiana²,

Mitsudo³

2016

ces

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The results from the use of microwaves for ceramic synthesis have showed different results than that of conventionally synthesis method. One of the group results consists of indirect evidence of diffusion such as observations of enhanced sintering, grain growth, or reaction zones. The other group consists of direct measurements of diffusivities and activation energies for diffusion during microwave processing. Understanding the physical mechanisms of microwave effect is play an important role in the synthesis of materials technologies employing microwave energy. Many different physical phenomena including thermal and non-thermal are involved in the microwave processing of ceramics known as 'microwave effect'. This paper describes analysis of recent research on microwave sintering of an oxide ceramic, a high purity -alumina. The experiment data used involved a wide range of microwave frequencies up to sub-238 Muhammad Zamrun Firihu et al. millimeter range which have been reported previously. Existing evidence as to that microwaves enhanced diffusions has been reviewed and will be discussed.

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Structural and Microwave Properties of Silica Xerogel Glass-Ceramic Sintered by Sub-millimeter Wave Heating using a Gyrotron

Cited by 19 publications

References 31 publications

Formation and Particle Growth of TiO2 in Silica Xerogel Glass Ceramic During a Sintering Process

Formation and Particle Growth of TiO2 in Silica Xerogel Glass Ceramic During a Sintering Process

Investigation of silica from rice husk ash wastes as an alternative material for microwave absorbers

Microwaves enhanced sintering mechanisms in alumina ceramic sintering experiments

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