scholarly journals Augite-anorthite glass-ceramics from residues of basalt quarry and ceramic wastes

2015 ◽  
Vol 9 (2) ◽  
pp. 117-123 ◽  
Author(s):  
Gamal Khater ◽  
Safiah Abu ◽  
Esmat Hamzawy
Keyword(s):  
Thermal Expansion ◽  
Glass Ceramic ◽  
Crystallization Process ◽  
Coefficient Of Thermal Expansion ◽  
Glass Ceramics ◽  
Ceramic Samples ◽  
Heat Treated ◽  
Prepared Glass ◽  
Higher Temperature ◽  
Dominant Phase

Dark brown glasses were prepared from residues of basalt quarries and wastes of ceramic factories. Addition of CaF2, Cr2O3 and their mixture CaF2-Cr2O3 were used as nucleation catalysts. Generally, structures with augite and anorthite as major phases and small amount of magnetite and olivine phases were developed through the crystallization process. In the samples heat treated at 900?C the dominant phase is augite, whereas the content of anorthite usually overcomes the augite at higher temperature (1100?C). Fine to medium homogenous microstructures were detected in the prepared glass-ceramic samples. The coefficient of thermal expansion and microhardnessmeasurements of the glass-ceramic samples were from 6.16?10-6 to 8.96?10-6?C-1 (in the 20-500?C) and 5.58 to 7.16GP, respectively.

BaO-Al2O3-SiO2-B2O3 Glass-Ceramic SOFCs Sealant: Effect of ZnO Additive

2017 ◽  
Vol 751 ◽  
pp. 455-460 ◽  
Author(s):  
Nattapol Laorodphan ◽  
Jiratchaya Ayawanna
Keyword(s):  
Heat Treatment ◽  
Thermal Expansion ◽  
Solid Oxide Fuel Cells ◽  
Glass Ceramic ◽  
Coefficient Of Thermal Expansion ◽  
Glass Ceramics ◽  
Treatment Temperature ◽  
X Ray ◽  
Barium Aluminosilicate ◽  
Xrd Patterns

The crystallization of planar solid oxide fuel cells (SOFCs) sealant glasses in the systems BaO-Al2O3-SiO2-B2O3 (BaBS) and BaO-Al2O3-SiO2-B2O3-ZnO (BaBS-Zn) was investigated via both X-ray diffractometer and scanning electron microscopy with energy dispersive spectroscopy. The effect of nucleation heat-treatment of the BaBS glass at different temperature for 5 hours, i.e. 550 and 590 °C, on the crystallization behavior was also studied. Thermal expansion profiles of the glasses indicate that both glasses have a low sealing temperature. XRD patterns of all BaBS glass-ceramics, devitrified at 800 °C for 30 hours, show that Ba2Si3O8, BaAl2Si2O8, Ba3B2O6 and some unknown crystalline phases were found. It was also found that crystalline size of unknown barium aluminosilicate with low silicon content depends on the nucleation heat-treatment temperature. For the ZnO-containing glass, ZnO reduces the coefficient of thermal expansion value of glass and causes the devitrification of large needle-like barium zinc silicate phases. The crack at the YSZ/BaBS-Zn glass-ceramic interface was also observed. Two barium silicate phases, which are BaZnSiO4 and BaZn2Si2O7 were devitrified in ZnO-containing glass-ceramic.

β-Spodumene Glass-Ceramic with Anomalous Low Thermal Expansion

2008 ◽  
Vol 39-40 ◽  
pp. 381-386 ◽  
Author(s):  
Akihiko Sakamoto ◽  
Yusuke Himei ◽  
Yoshio Hashibe
Keyword(s):  
Thermal Expansion ◽  
Mechanical Strength ◽  
Ceramic Material ◽  
Glass Ceramic ◽  
Silica Glass ◽  
Coefficient Of Thermal Expansion ◽  
Glass Ceramics ◽  
New Method ◽  
Low Thermal Expansion ◽  
Natural Stones

To survey new method for controlling thermal expansion of glass-ceramic material, we studied the coefficient of thermal expansion (CTE) and the microstructure of β-spodumene glass-ceramics. We found that the CTE of the β-spodumene glass-ceramics is remarkably reduced by introducing interstices at the boundary between the crystalline and glass phases. Despite its relatively low crystallinity (45vol%), a newly developed glass-ceramic showed an anomalous low thermal expansion of 7x10-7 /oC, which compares to that of silica glass. The mechanical strength of this glass-ceramic was at the same level as that of natural stones: marble and granite.

Influence of Bi2O3 on Crystalline Phase Content and Thermal Properties of Åkermanite and Diopside Based Glass-Ceramic Sealant for SOFCs

2017 ◽  
Vol 751 ◽  
pp. 483-488
Author(s):  
Pornchanok Lawita ◽  
Apirat Theerapapvisetpong ◽  
Sirithan Jiemsirilers
Keyword(s):  
Thermal Expansion ◽  
Thermal Properties ◽  
Glass Ceramic ◽  
Crystalline Phase ◽  
Coefficient Of Thermal Expansion ◽  
Glass Ceramics ◽  
Clean Energy ◽  
Softening Temperature ◽  
Quantitative Phase Analysis ◽  
Clean Energy Source

Solid oxide fuel cell (SOFC) is an electrochemical energy conversion device which is considered as clean energy source generator with reliability and relatively inexpensive production cost. One of the most important components for planar design SOFC is the hermetic seal that prevents fuel from leaking out of between the stack of fuel cells. Glass-ceramics are attractive materials as sealing materials for this device. The expected coefficient of thermal expansion (CTE) of the glass-ceramic sealants should be between 9 and 12 x 10−6 K−1. Glass – ceramics based on åkermanite (Ca2MgSi2O7) crystalline phase were reported their high CTE value from about 10 to 11.3 x 10−6 K−1. In this study, glass compositions in the CaO-MgO-B2O3-Al2O3-SiO2 system with varying amounts of Bi2O3 from 0 to 10 wt. % were prepared by conventional melting and investigated their properties. The selected compositions were derived from ternary åkermanite–forsterite–anorthite phase diagram. Phase composition and quantitative phase analysis of glass–ceramics were examined by X-ray diffractometer. The onset of crystallization (Tx) and crystallization temperature (Tc) were measured by DTA. The thermal properties of bulk glass samples and heat treated samples at 900 oC for 2 h which were glass transition temperature (Tg), dilatometric softening temperature (Ts), and coefficient of thermal expansion (CTE) were determined by dilatometer. Furthermore, the long-term stability of their CTE was investigated. The samples were continued to soak at 800 °C for 100 h and observed their change in CTE value. The results found that the åkermanite phase tended to increase with increasing amount of Bi2O3 content.

Effect of Forming Pressure and Sintering Temperature on Thermal Expansion Property of Li2O-Al2O3-P2O5-SiO2 Glass-Ceramics

2011 ◽  
Vol 197-198 ◽  
pp. 436-439
Author(s):  
Min Hua Luo ◽  
Zhuo Hao Xiao
Keyword(s):  
Thermal Expansion ◽  
Sintering Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Thermal Expansion Property ◽  
Expansion Property ◽  
Prepared Glass

Li2O-Al2O3-P2O5-SiO2 xerogel powders were synthesized by sol-gel route and glass-ceramics were prepared under different forming pressure and sintering temperature. The effects of sintering temperature and forming pressure on coefficient of thermal expansion of prepared glass-ceramics were investigated by means of DTA-TG, TEC and XRD. The results indicate that xerogel powders crystallization begins at 785°C, and the main crystallite phases in the researched specimens are virgilite and cristobalite. The TEC decreases linearly with the forming pressure. When the sintering temperature is 950°C and forming pressure is 40MPa, a low TEC of 0.65×10-6 °C-1 can be obtained.

scholarly journals Mono-crystalline nanometer high cristobalite glass-ceramic from nominal pyroxene glass

2021 ◽  
Author(s):  
Amira EL-Rafei ◽  
Moenis A Azoz ◽  
Esmat M A Hamzawy
Keyword(s):  
Antimicrobial Activity ◽  
Thermal Expansion ◽  
Candida Albicans ◽  
Coefficient Of Thermal Expansion ◽  
Inhibition Zone ◽  
Glassy Matrix ◽  
Transparent Glass ◽  
Heat Treated ◽  
Prepared Glass ◽  
Pyroxene Glass

Abstract Transparent glass was prepared from nominal alkali pyroxene (Na2 Mg Si2O6) composition. Incorporation of Cr2O3 in alkali pyroxene composition in two % (0.5 and 1.0) increases the crystallization temperature. High cristobalite was developed alone in all glass samples heat-treated at 800°C. The microstructure shows nanometer crystals of high cristobalite which spread in glassy matrix. The densities, hardness and coefficient of thermal expansion were between 2.49 and 2.53 g/cm3, 505 and 611 kg/mm2 and between 9.38 and 13.32 x 10− 6°C− 1 (30–300 ˚C ) respectively. The antimicrobial activity of the prepared glass and ceramics shows that the only samples contain 1% of Cr2O3shows an inhibition zone in case of Candida albicans yeast.

Study of the thermal stability of Zerodur glass ceramics suitable for a scanning probe microscope frame

Open Physics ◽  
2012 ◽  
Vol 10 (2) ◽  
Author(s):  
Ondřej Číp ◽  
Radek Šmíd ◽  
Martin Čížek ◽  
Zdeněk Buchta ◽  
Josef Lazar
Keyword(s):  
Glass Ceramic ◽  
Coefficient Of Thermal Expansion ◽  
Frequency Comb ◽  
Thermal Characteristic ◽  
Glass Ceramics ◽  
Tunable Laser ◽  
Tunable Laser Diode ◽  
Optical Mixing ◽  
Length Changes ◽  
Set Up

AbstractThe work presents measurements of the length stability of Zerodur glass ceramic with temperature change. Measurement of this thermal characteristic is necessary for determination of the optimal temperature at which the Zerodur glass ceramic has a coefficient of thermal expansion close to zero. The principle of the measurement is to monitor the length changes using an optical resonator with a cavity mirror spacer made from the Zerodur material to be studied. The resonator is placed inside a vacuum chamber with a temperature control. A tunable laser diode is locked to a certain optical mode of the resonator to monitor the optical frequency of this mode. A beat-note signal from optical mixing between the laser and a stabilized femtosecond frequency comb is detected and processed. The temperature dependence of the glass ceramics was determined and analyzed. The resolution of the length measurement of the experimental set-up is on the order of 0.1 nm.

Crystallization Behavior and Performance of MgO-Al2O3-SiO2 Glass-Ceramics by Sintering

2010 ◽  
Vol 92 ◽  
pp. 65-71 ◽  
Author(s):  
Pei Xin Zhang ◽  
Li Gao ◽  
Qiu Hua Yuan ◽  
Hai Lin Peng ◽  
Xiang Zhong Ren ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Flexural Strength ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Crystallization Process ◽  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Low Thermal Expansion ◽  
Main Crystalline Phase ◽  
And Performance

The glass-ceramics of MgO-Al2O3-SiO2 system were prepared by sintering technology. The crystallization process of MgO-Al2O3-SiO2 glass-ceramics was investigated with X-ray diffraction (XRD), scanning electron microscopy (SEM), and other techniques; the discussion of breaking strength, thermal expansion coefficient and relevant properties at different sintering temperatures was also presented. The results show that: (1) The main crystalline phase isα-cordierite at different sintering temperatures, and the samples show high flexural strength and low thermal expansion coefficient; (2) with the increase of sintering temperature, the content of crystal phase increases, while the thermal expansion coefficient decreases evidently, the flexural strength and tightness density rise up first, then go down.

HIPed Tailored Pyrochlore-Rich Glass-Ceramic Waste Forms for the Immobilization of Nuclear Waste

2008 ◽  
Vol 1124 ◽  
Author(s):  
Melody Lyn Carter ◽  
Hui Li ◽  
Yingjie Zhang ◽  
Andrew L Gillen ◽  
Eric R Vance
Keyword(s):  
Nuclear Waste ◽  
Glass Ceramic ◽  
Glass Ceramics ◽  
Spectroscopic Characterization ◽  
Chemical Durability ◽  
Intermediate Level ◽  
Crystalline Phases ◽  
Waste Forms ◽  
Ceramic Samples

AbstractHot isostatically pressed (HIPed) glass-ceramics for the immobilization of uranium-rich intermediate-level wastes and Hanford K-basin sludges were designed. These were based on pyrochlore-structured Ca(1-x)U(1+y)Ti2O7 in glass, together with minor crystalline phases. Detailed microstructural, diffraction and spectroscopic characterization of selected glass-ceramic samples has been performed, and chemical durability is adequate, as measured by both MCC-1 and PCT-B leach tests.

scholarly journals Photoluminescence of Eu and Ce Activated Oxyfluoride Glass And Glass Ceramics/ Eu Un Ce Jonu Luminiscence Oksifluorīdu Stiklos Un Stikla Keramikā

2012 ◽  
Vol 49 (6-I) ◽  
pp. 44-48
Author(s):  
I. Brice ◽  
U. Rogulis ◽  
E. Elsts ◽  
J. Grūbe
Keyword(s):  
Glass Ceramic ◽  
Glass Ceramics ◽  
Oxyfluoride Glass ◽  
Ceramic Samples ◽  
Activator Ions

Abstract The photoluminescence of SiO2-Al2O3-LiO2-LaF3 oxyfluoride glass and glass ceramic samples doped with Ce3+, Eu2+ and Ce3+/Eu2+ is investigated, and the spectra and fluorescence intensities are compared. The luminescence of samples activated by Eu ions is found to be more intensive than of the samples doped with Ce or Ce/Eu. The luminescence of glass ceramics is higher than that of the corresponding glass, which indicates that a proportion of the activator ions are embedded in the fluoride crystallites.

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