Effect of ZnO on Thermo Physical and Structural Properties of Lithium Zinc Silicate Glass-Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 947-952 ◽  
Author(s):  
Govind P. Kothiyal ◽  
B.I. Sharma ◽  
V.K. Shrikhande ◽  
Madhumita Goswami ◽  
J.V. Yakhmi
Keyword(s):  
Glass Matrix ◽  
Glass Ceramics ◽  
Zinc Content ◽  
Zinc Silicate ◽  
Remarkable Difference ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Zinc ◽  
Controlled Nucleation ◽  
Thermo Physical Properties

Lithium zinc silicate (LZS) glass-ceramics with compositions: (a) Li2O-ZnO-SiO2-Na2OB2O3- P2O5 and (b) Li2O-ZnO-SiO2-K2O-Al2O3-B2O3-P2O5 have been prepared by controlled nucleation and crystallization. The effect of ZnO/(ZnO+SiO2) ratio on various thermo-physical properties was investigated by changing the ratio from 0.1 to 0.31 in the case of (a). Different crystalline phases have been identified by X-ray diffraction studies in glass-ceramics including cristobalite, Li3Zn0.5SiO4 and Li2SiO3. Density ( r) was found to increase from 2.62 to 2.82 gm cm-3 while microhardness (VHN) decreased from 6.56 to 5.79 GPa with increase in ZnO/(ZnO+SiO2) ratio in the glass-ceramics. Average thermal expansion coefficient (TEC) in the temperature range 30 to 450oC increased from 125x10-7 to 185x10-7 /oC. The increase in TEC and decrease in microhardness are thought to be due to the formation of different phases, which in turn influence the rigidity/bonding in the glass-ceramics. A remarkable difference in the microstructure close to interface of the glass-ceramics to Cu seal was seen in both the cases [high ZnO content (a) of ZnO/(ZnO+SiO2) ratio 0.31 and low ZnO content (b) of ZnO/(ZnO+SiO2) ratio 0.024]. Both the microstructures showed globally two contrast phases of bright and dark dispersed in the glass matrix. An interesting dandritic phase observed towards core in the microstructure for the high zinc content is not seen in the microstructure for low zinc content glass-ceramic. The seal withstands a vacuum of ~ 10-6 torr at helium leak rate of 3x10-10 torr litre/sec.

Effect of BaO on Thermo-Physical Properties of Lithium Zinc Silicate Glass-Ceramics

2011 ◽  
Vol 299-300 ◽  
pp. 503-507 ◽  
Author(s):  
Bin Zhai ◽  
Xiao Li Zhou ◽  
Shang Ru Zhai ◽  
Zhi Qiang Wang
Keyword(s):  
Electron Microscopy ◽  
Physical Properties ◽  
Expansion Coefficient ◽  
Glass Ceramics ◽  
Zinc Silicate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Composite Glass ◽  
Thermo Physical Properties ◽  
Scanning Electron

Lithium zinc silicate (LZS) glasses containing Li2O–ZnO–SiO2–Na2O–B2O3–BaO–P2O5 with different BaO/(BaO+ZnO) ratios were prepared by conventional melt and quench technique and subsequently converted into glass-ceramics. The effect of BaO/(BaO+ZnO) ratio on various thermo-physical properties was investigated by changing the ratio from 0 to 0.226. The crystalline phases were characterized by X-ray diffraction technique on the composite glass-ceramics, including Li3Zn0.5SiO4, Li2OZnSiO4 and cristobalite phase. The thermal expansion coefficient (TEC) in the temperature range 70–400 oC increased from 107 × 10-7 to 141 ×10-7 / oC. The increase in expansion coefficient was associated with the formation of different phases which in turn influenced the rigidity/bonding in the glass-ceramics. The microstructure was analyzed by scanning electron microscopy (SEM), and the grain size became bigger after the addition of BaO.

Immobilisation of Simulated Plutonium-Contaminated Material in Phosphate Glass: An Initial Scoping Study

2006 ◽  
Vol 932 ◽  
Author(s):  
Paul A. Bingham ◽  
Russell J. Hand ◽  
Charlie R. Scales
Keyword(s):  
Phosphate Glass ◽  
Glass Matrix ◽  
Glass Ceramics ◽  
Additional Benefit ◽  
Phosphate Glasses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pu Isotopes ◽  
Waste Loading ◽  
Low Levels

ABSTRACTVitrification is a potential route for the immobilisation of Plutonium Contaminated Material (PCM). This is an Intermediate Level Waste (ILW) arising from operations in which there is contact with Pu isotopes. PCM consists of low levels of Pu combined with metals, masonry, glass, ceramics, polymers and other carbonaceous materials. Simulated PCM containing CeO2 as a PuO2 surrogate was mixed with a phosphate precursor and vitrified. Pre-oxidation of PCM simulant prior to vitrification minimised the violence of batch reactions. No pre-oxidation produced inhomogeneous slag-like materials with high residual metals and particulates. Pre-oxidation at 600°C in air and at 1200°C in an O2-rich atmosphere produced more favourable results, with increasingly vitreous products resulting from more oxidised PCM simulant. The most oxidised PCM simulant produced phosphate glasses with low levels of particulate inclusions, as confirmed by x-ray diffraction and scanning electron microscopy. Particulates included iron-rich metallics and aluminous oxides. Increased melting times and temperatures may have reduced the number of inclusions slightly, but O2 bubbling during melting resulted in little additional benefit. Waste loading equivalent to ∼60 weight % of untreated waste may be possible. There was little evidence of Ce partitioning, indicating that it was immobilised within the glass matrix and had little preference for metallic or crystalline phases. These results demonstrate the potential feasibility for vitrification of PCM in phosphate glass, justifying further investigation into this potentially novel solution.

In Situ X-Ray Diffraction Studies of Crystallization Growth Behavior in ZnO-Bi2O3-B2O3 Glass as a Route to Functional Optical Devices

MRS Advances ◽  
2018 ◽  
Vol 3 (11) ◽  
pp. 563-567 ◽  
Author(s):  
Quentin Altemose ◽  
Katrina Raichle ◽  
Brittani Schnable ◽  
Casey Schwarz ◽  
Myungkoo Kang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Glass Ceramics ◽  
Treatment Temperature ◽  
Crystal Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Xrd ◽  
Dsc Measurements ◽  
Transmission Window

ABSTRACTTransparent optical ZnO–Bi2O3–B2O3 (ZBB) glass-ceramics were created by the melt quenching technique. In this work, a melt of the glass containing stoichiometric ratios of Zn/Bi/B and As was studied. Differential scanning calorimeter (DSC) measurements was used to measure the thermal behavior. VIS/NIR transmission measurements were used to determine the transmission window. X-ray diffraction (XRD) was used to determine crystal phase. In this study, we explore new techniques and report a detailed study of in-situ XRD of the ZBB composition in order to correlate nucleation temperature, heat treatment temperature, and heat treatment duration with induced crystal phase.

scholarly journals Bone bonding ability of some borate bio-glasses and their corresponding glass-ceramic derivatives

2012 ◽  
Vol 6 (4) ◽  
pp. 183-192 ◽  
Author(s):  
Fatma Margha ◽  
Amr Abdelghany
Keyword(s):  
Heat Treatment ◽  
Fourier Transform ◽  
Glass Ceramic ◽  
Glass Composition ◽  
Glass Ceramics ◽  
Soda Lime ◽  
Phosphate Solution ◽  
Borate Glasses ◽  
X Ray Diffraction ◽  
X Ray

Ternary borate glasses from the system Na2O?CaO?B2O3 together with soda-lime-borate samples containing 5 wt.% of MgO, Al2O3, SiO2 or P2O5 were prepared. The obtained glasses were converted to their glass-ceramic derivatives by controlled heat treatment. X-ray diffraction was employed to investigate the separated crys?talline phases in glass-ceramics after heat treatment of the glassy samples. The glasses and corresponding glass-ceramics after immersion in water or diluted phosphate solution for extended times were characterized by the grain method (adopted by several authors and recommended by ASTM) and Fourier-transform infrared spectra to justify the formation of hydroxyapatite as an indication of the bone bonding ability. The influence of glass composition on bioactivity potential was discussed too.

The Effect of Zinc Content on n-Pentane Isomerisation Over Zn–S2O82–/ZrO2–Al2O3 Catalyst

2017 ◽  
Vol 42 (1) ◽  
pp. 23-29
Author(s):  
Hua Song ◽  
Shengnan Li ◽  
Hualin Song ◽  
Feng Li ◽  
Huapeng Cui
Keyword(s):  
Zinc Content ◽  
Space Velocity ◽  
X Ray Diffraction ◽  
Sulfate Ions ◽  
X Ray ◽  
Weight Hourly Space Velocity ◽  
Mass Fractions ◽  
Crystallite Sizes ◽  
Temperature Programmed ◽  
Al2o3 Catalyst

A number of Zn–S2O82–/ZrO2–Al2O3 (Zn( x)–SZA) catalysts with different Zn mass fractions were synthesised and characterised by using X-ray diffraction, the Brunauer–Emmett–Teller method, and H2 temperature-programmed reduction. The structure and isomerisation performance of Zn( x)–SZA catalysts were studied using n-pentane as a probe reaction. The results showed that a pure tetragonal ZrO2 phase was formed on Zn( x)–SZA, and the ZrO2 crystallite sizes of the tetragonal phase increased in the order: Zn(0.5)–SZA < Zn(1.0)–SZA < Zn(1.5)–SZA < Zn(2.0)–SZA < SZA. Zn can strengthen the interaction between persulfate ions and the support, promote the formation of stronger acidity, lead to a better dispersion of sulfate ions on the surface, and improve the redox performance of the catalysts. The Zn(1.0)–SZA catalyst exhibited the best catalytic activity for n-pentane isomerisation. At a temperature of 170 °C, a reaction pressure of 2.0 MPa, a molar H2/ n-pentane ratio of 4:1, and a weight hourly space velocity of 1.0 h−1, the isopentane yield reached 58.0%.

Structure Characterization of Sintered CaO-Al2O3-SiO2 Glass-Ceramic Reinforced with Spodumene

2013 ◽  
Vol 834-836 ◽  
pp. 309-314
Author(s):  
Zi Fan Xiao ◽  
Jin Shu Cheng ◽  
Jun Xie
Keyword(s):  
Glass Ceramic ◽  
Energy Dispersive Spectrometry ◽  
Crystal Size ◽  
Bending Strength ◽  
Glass Ceramics ◽  
Structure Characterization ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
X Ray

A glass-ceramic belonging to the CaO-Al2O3-SiO2(CAS) system with different composition of spodumene and doping the Li2O with amount between 0~2.5 % (mass fraction) were prepared by onestage heat treatment, under sintering and crystallization temperature at 1120 °C for two hours. In this paper, differential thermal analysis, X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and bending strength test were employed to investigate the microstructure and properties of all samples. β-wollastonite crystals were identified as the major crystalline phases, and increasing Li2O was found to be benefit for the crystallization and tiny crystalline phases remelting, resulting in the content of major crystalline phases increased first and then decreased with increasing the expense of spodumene. Meanwhile, the crystal size can be positively related with the content of Li2O. The preferable admixed dosage of spodumene can be obtained, besides the strength of glass-ceramics can be more than 90 MPa.

The Effects of Preparation Conditions And Chemical Composition On CMAS Glass Ceramics With One Step Process

2021 ◽  
Author(s):  
Yuliang Guo ◽  
Huixin Jin ◽  
Yuandan Xiao ◽  
Huahao Song ◽  
Shangjiefu Wang
Keyword(s):  
Solid Waste ◽  
Theoretical Basis ◽  
Chromium Content ◽  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Crystallization Activation Energy ◽  
X Ray ◽  
Preparation Conditions ◽  
Treatment Conditions ◽  
One Step

Abstract Based on the composition of Cr-doped solid waste, other oxides were added to adjust the composition to prepare glass-ceramics with on step composition, and the effect of heat treatment system (including temperature and holding time), chromium content, MnO and Fe2O3 doped on the crystallization and physical properties of glass-ceramics was studied. The samples were characterized by X-ray diffraction, differential thermal analysis and scanning electron microscopy. The results show that the best treatment conditions are 1090 ℃ for 4h, and the amount of dissolved chromium reaches 5%. The main crystallization phase is diopside and anorthite. The hardness and chemical stability of the material were measured. The doping of MnO and Fe2O3 increases the crystallization activation energy of glass ceramics, and makes the crystal phase more uniform as the SEM results. This experiment provides a theoretical basis for the preparation of CMAS glass ceramics from chromium containing solid waste.

scholarly journals Five-fold twinned β-PbF2 nanocrystals in oxyfluoride glass ceramics

RSC Advances ◽  
2018 ◽  
Vol 8 (71) ◽  
pp. 40787-40793 ◽  
Author(s):  
Yuao Guo ◽  
Lijuan Zhao ◽  
Yuting Fu ◽  
Pan Dong ◽  
Liying Guo ◽  
...  
Keyword(s):  
Glass Ceramics ◽  
Lanthanide Ions ◽  
X Ray Diffraction ◽  
Oxyfluoride Glass ◽  
X Ray ◽  
Trivalent Lanthanide ◽  
Quenching Method

Oxyfluoride glass ceramics (GCs) doped with trivalent lanthanide ions (Ln3+) have been prepared using a conventional melting–quenching method and studied by X-ray diffraction (XRD).

Effects of Glass Elements on the Structural Evolution ofin situGrown Ferroelectric Perovskite Crystals in Sol-gel Derived Glass-ceramics

1997 ◽  
Vol 12 (4) ◽  
pp. 1131-1140 ◽  
Author(s):  
Kui Yao ◽  
Weiguang Zhu ◽  
Liangying Zhang ◽  
Xi Yao
Keyword(s):  
Crystallization Process ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Structural Evolution ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
Process Change ◽  
X Ray ◽  
Ferroelectric Perovskite

Several ABO3perovskite ferroelectric crystals, PbTiO3, Pb(Zr, Ti)O3, and BaTiO3have beenin situgrown from amorphous gels with glass elements, and the structural evolution has been systematically investigated using x-ray diffraction (XRD), infrared spectra (IR), differential thermal analysis (DTA), thermogravimetric analysis (TGA), and dielectric measurements. It is found that in the Si-contained glass-ceramic systems, Si and B glass elements are incorporated into the crystalline structures, resulting in the variation of the crystallization process, change of lattice constant, and dielectric properties. Some metastable phases expressed by a general formula AxByGzOw(A = Pb and Ba; B = Zr and Ti; G for glass elements, especially for Si) have been observed and discussed.

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