Crystallization of gels and glasses made from hot-pressed gels

Phalippou, J.; Prassas, M.; Zarzycki, J.

doi:10.1016/0022-3093(82)90243-5

Cited by 94 publications

(24 citation statements)

References 10 publications

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“…The intense band observed at 1101 cm À1 is ascribed to the combination of P-O stretching vibration of P-O-P and P-O-Si bridging units associated with polymeric sheet structure and also may be due to the stretching mode of Si-O-Si. The band at 933 cm À1 may be assigned to Si-O stretching vibration of Si-O-Si and P-O-Si bridging units [17][18][19][20]. The FTIR band at 813 cm À1 could be assigned to the symmetric stretching of Si-O, bending motions of P-O-P, Si-O-P and O-P-O units.…”

Section: Resultsmentioning

confidence: 97%

“…2, it is observed that LPBS gels heated in the temperature region of 573-678 K showed peak free patterns that confirmed the amorphous nature. The XRD patterns showed mixed nature, amorphous and crystalline, for heat treated gels below 573 K and above 678 K [3,[16][17][18]. Thus, from XRD analysis, the optimal temperature region (573-678 K) is fixed for the synthesis of LPBS glass samples by sol-gel process with various nitric acid concentrations.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Acid catalyst concentration effect on structure and ion relaxation studies of Li2O–P2O5–B2O3–SiO2 glasses synthesized by sol–gel process

Muralidharan

Venkateswarlu

Satyanarayana

2005

Journal of Non-Crystalline Solids

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Acid catalyst concentration effect on structure and ion relaxation studies of Li2O–P2O5–B2O3–SiO2 glasses synthesized by sol–gel process

Muralidharan

Venkateswarlu

Satyanarayana

2005

Journal of Non-Crystalline Solids

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“…Such impurities may extend the stability field of cristobalite (e.g., Venezia et al 2001). The influence of impurities on the crystallization of cristobalite has been investigated by annealing experiments of vitreous silica in presence of impurities (water or alkali for instance) within the temperature range 700-900 °C (e.g., Phalippou et al 1982;Chao and Lu 2000;Jean et al 2001;Bruhns and Fischer 2000). Among other impurities, the presence of water in the residual melt is suggested by the occurrence of apatite and chloroapatite, which usually contain significant amount of hydroxyls.…”

Section: Origin and Significance Of Cristobalite And Quartzmentioning

confidence: 99%

Magmatic cristobalite and quartz in the NWA 856 Martian meteorite

Leroux¹

2006

Meteoritics &Amp; Planetary Science

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Abstract-Silica-rich late-stage crystallization pockets in the Martian meteorite Northwest Africa (NWA) 856 were investigated by transmission electron microscopy (TEM). The pockets occur as wedges between maskelynite laths or between maskelynite and pyroxene. They consist of elongated grains of cristobalite and quartz embedded in a silica-rich glass. Interstitial to the amorphous phase and silica minerals, a number of small accessory minerals have been identified, typical for late-stage crystallization products. They are ilmenite, tranquillityite, fayalite, troilite, baddeleyite, apatite, and chloroapatite. Cristobalite and quartz are shocked, as revealed by the occurrence of numerous amorphous lamellae. This assemblage suggests metastable dendritic crystallization under hydrous conditions. Cristobalite crystallization was probably facilitated by the presence of impurities such as Na or H 2 O. Our observations show that silica minerals can be formed under magmatic conditions on Mars.

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“…By varying the molar ratio of Ba(Ac) 2 /Ti(OBu n ) 4 / Si(OEt) 4 , the dielectric constant of Ba 2 TiSi 2 O 8 glass ceramics could be tunable in the range of 6-12. The low sintering temperature (<900°C), along with low dielectric constant (6)(7)(8)(9)(10)(11)(12) and low loss tangent (<2 × 10 −3 ), make the Ba 2 TiSi 2 O 8 glass ceramics attractive for using as LTCC dielectrics.…”

Section: Resultsmentioning

confidence: 99%

“…The main disadvantages of this method are the poor homogeneity of melt and the high processing temperature (>1400°C) [7,8]. More recently, the sol-gel technique has been widely used as an alternative method for preparing glass or glass-ceramics [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and dielectric properties of Ba2TiSi2O8 glass-ceramics from the sol–gel process

et al. 2007

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The Ba 2 TiSi 2 O 8 glass-ceramics were prepared by sol-gel process using barium acetate, titanium butoxide, tetraethoxyorthosilicate and boric acid as raw materials. Because of the existence of glass and sintering additive, the Ba 2 TiSi 2 O 8 glass-ceramics can be sintered at 880°C in air. The structure of sintered sample was characterized by means of XRD and SEM. XRD patterns showed that fresnoite Ba 2 TiSi 2 O 8 is the dominant crystalline phase in the sintered samples. SEM images indicated that the shape of Ba 2 TiSi 2 O 8 grains varied with the molar ratio of ([Ba (Ac) 2 /Ti(OBu n ) 4 /Si(OEt) 4 ]). With an increase of Si(OEt) 4 content, the length/diameter ratio of Ba 2 TiSi 2 O 8 grains decreases. The Ba 2 TiSi 2 O 8 glass-ceramics studied in this work have ɛ r in the range of 6-12 (100 MHz) and demonstrate very low dielectric losses (tanδ <2×10 −3 , 100 MHz). The experimental results suggested that the Ba 2 TiSi 2 O 8 glass-ceramics could be used as dielectric materials for low temperature co-fired ceramics (LTCC) process.

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Crystallization of gels and glasses made from hot-pressed gels

Cited by 94 publications

References 10 publications

Acid catalyst concentration effect on structure and ion relaxation studies of Li2O–P2O5–B2O3–SiO2 glasses synthesized by sol–gel process

Acid catalyst concentration effect on structure and ion relaxation studies of Li2O–P2O5–B2O3–SiO2 glasses synthesized by sol–gel process

Magmatic cristobalite and quartz in the NWA 856 Martian meteorite

Synthesis and dielectric properties of Ba2TiSi2O8 glass-ceramics from the sol–gel process

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