Transparent Glass-Ceramics Derived from Spontaneously Crystallized Phosphosilicte Glasses

2011 ◽  
Vol 239-242 ◽  
pp. 1096-1100
Author(s):  
Shu Jiang Liu ◽  
Yan Fei Zhang
Keyword(s):  
Glass Ceramics ◽  
Compositional Variation ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Rich Phase ◽  
Transparent Glass ◽  
X Ray ◽  
Phosphosilicate Glass ◽  
Degree Of Crystallization ◽  
Good Transparency

Transparent phosphosilicate glass-ceramics were prepared by heating the spontaneously crystallized precursor glasses in which crystals have formed during cooling of the melts. And the effects of compositional variation on the crystalline phases, degree of crystallization and transparency were investigated by using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). It is found that Mg2+tends to exist in silicate-rich phase rather than phosphate-rich phase, such MgO is more beneficial to the transparency of phosphosilicate glass-ceremics compared to CaO. In addition, the substitution of P2O5for SiO2enhances the tendency of phase separation, and hence the precipitation of Na2MgSiO4crystals for the precursor glasses as well as glass-ceramics with good transparency.

Preparation and Characterization of Transparent Oxyfluoride Tellurite Glass-Ceramics Containing CaF2 Nanocrystals

2014 ◽  
Vol 989-994 ◽  
pp. 305-307
Author(s):  
Zhao Xia Hou ◽  
Hang Xin Li ◽  
Shao Hong Wang ◽  
Mei Han Wang ◽  
Xiao Dan Hu
Keyword(s):  
Tellurite Glass ◽  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Melting Method ◽  
X Ray ◽  
Average Size ◽  
Scanning Electron ◽  
Temperature Melting

Transparent oxyfluoride tellurite glass-ceramics containing CaF2 nanocrystals were prepared by high temperature melting method. The glass-ceramics were characterized by Differential scanning calorimetry, X-ray diffraction and scanning electron microscope, respectively. The results showed that the CaF2 nanocrystals were spherical and the average size was found to be 60 nm.

Glass-Ceramics Obtained from Sewage Sludge and its Characteristics Affected by Alkalinity

2014 ◽  
Vol 937 ◽  
pp. 70-73
Author(s):  
Di Wu ◽  
Jun Zhang ◽  
Xing Wang Wen ◽  
Hui Ling Liu
Keyword(s):  
Sewage Sludge ◽  
Raw Materials ◽  
Glass Ceramics ◽  
Chemical Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Sludge Disposal ◽  
Physical And Chemical ◽  
And Chemical Properties

Sewage sludge was tested as component for producing glass-ceramics with the addition of analytic reagent CaO to solve the sewage sludge disposal problems. The effect of alkalinity (Ak=mCaO/mSiO2) on the characteristics of the glass-ceramics was investigated. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were used to investigate thermal behavior and crystalline phase of the samples. It was found that the degree and characteristics of crystals in vitrified sludge significantly correlate to the alkalinity of the raw materials. The glass-ceramics with Ak = 0.36 possessed the best physical and chemical properties.

Spontaneous Crystallization Behavior of Phosphosilicate Glasses

2011 ◽  
Vol 183-185 ◽  
pp. 1626-1630
Author(s):  
Shu Jiang Liu ◽  
Yan Fei Zhang
Keyword(s):  
Alkaline Earth ◽  
Crystallization Behavior ◽  
Relative Content ◽  
The Other ◽  
Compositional Variation ◽  
X Ray Diffraction ◽  
Spontaneous Crystallization ◽  
X Ray ◽  
Degree Of Crystallization ◽  
Scanning Electron

We studied the spontaneous crystallization behavior for 60.5SiO2-2.5Al2O3-3P2O5- 18Na2O-16RMgO-16(1-R)CaO system glasses during cooling of melts through changing the relative content of alkaline-earth oxides. Such compositional variation leads to the formation of different crystalline phases, as well as different degree of crystallization, with the help of X-ray diffraction (XRD), heat capacity (Cp) and scanning electron microscopy (SEM). It is found that the obtained glasses are opalescent due to formation of orthorhombic NaCaPO4 during cooling when R≤0.5, and the degree of crystallization increases with substituting MgO for CaO. On the other hand, the spontaneous crystallized phases is hexagonal NaCaPO4 for R=0.75 and is Na2MgSiO4 for R=1.0, respectively, and besides, the appearance become transparent.

Temperature-Controlled Devitrification of Oxyfluoride Borate Glasses

2007 ◽  
Vol 130 ◽  
pp. 263-266 ◽  
Author(s):  
Joanna Pisarska ◽  
Tomasz Goryczka ◽  
Wojciech A. Pisarski
Keyword(s):  
Heat Treatment ◽  
Glass Ceramics ◽  
Borate Glasses ◽  
X Ray Diffraction ◽  
Transparent Glass ◽  
X Ray ◽  
Heat Treated ◽  
Before And After ◽  
Controlled Crystallization ◽  
Temperature Controlled

Selected oxyfluoroborate glasses have been investigated before and after heat treatment. Transparent glass-ceramics (TGC) were obtained during controlled crystallization (devitrification). X-ray diffraction studies confirmed that material was partially crystallized. Diffraction lines due to orthorhombic PbF2 phase were identified for heat-treated samples at various temperatures and times. Results were compared to that ones obtained for as-melted glass.

Influence of Nucleating Additions on the Crystallization in the CaO-MgO-Al2O3-SiO2 Glass-Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 1408-1411 ◽  
Author(s):  
Qing Bo Tian ◽  
Yue Wang ◽  
Li Ming Feng ◽  
Xiu Hui Wang ◽  
Hong Gao
Keyword(s):  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Crystalline Phases ◽  
Layer Compound ◽  
X Ray ◽  
Fibrous Morphology ◽  
Inner Region ◽  
Compound Surface ◽  
Fine Dendrite

The crystallization behaviors and microstructural developments in the CaO-MgO- Al2O3-SiO2 glass with Fe2O3, ZrO2 and F as additives were investigated by using scanning electron microscopy, X-ray diffraction and differential scanning calorimetry techniques. In the glass sample with 1.0wt% Fe2O3, only surface crystallization were observed, in which a three-layer compound surface containing the fine dendrite, finer fibrous morphology and particle-shaped crystals was formed respectively from the near free surface to the inner region. The crystalline phases precipitated were anorthite and wollastonite at 1000°C, and diopside at 1040°C. The addition of ZrO2 suppressed the nucleation and growth of the crystalline phases. The addition of another 4.0wt% fluorine into the glass with a pair of 1.0wt% Fe2O3 and 2.0wt% ZrO2 induced the bulk crystallization, the surface and bulk crystallizations were both observed at 1040°C. At the surface, a three-layer morphology, which had similar morphology to the glass with 1.0wt% Fe2O3 was formed. In the bulk region, the block-shaped crystalline phases were precipitated homogeneously in the residual glass.

scholarly journals Structural Role of Nd2O3 as Dopant Material in Modified Borate Glasses and Glass Ceramics

2021 ◽  
Author(s):  
M. A. Shaalan ◽  
Gomaa El-Damrawi ◽  
A.K. Hassan ◽  
M. Hamed Misbah
Keyword(s):  
Molar Volume ◽  
Glass Structure ◽  
Glass Ceramics ◽  
Glass Network ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Melt Quenching ◽  
Scanning Calorimetry ◽  
X Ray

Abstract Glasses in the system xNd2O3-(46-x)B2O3-27CaO-24.4Na2O-2.6 P2O5 (0 ≤ x ≤ 4 mol%) have been prepared via conventional melt quenching technique. X-ray diffraction (XRD) spectra have showed that the amorphous structure is dominant in glasses of Nd2O3 concentrations ≤ 0.5 mol%. But formation of a more ordered structure is confirmed at higher Nd2O3 values. Result based on differential scanning calorimetry (DSC) shows an increase in glass transition temperature (Tg) with increasing Nd2O3 at expense of B2O3 contents. Vicker hardness (Hv) and density (D) are used to correlate the glass structure with its properties. The measured density is found to be increased whereas the molar volume is decreased with increasing Nd2O3 content. The calculated molar volume (Vm) and free spaces (Vf) are both decreased due to filling process which is suggested to be carried out by Nd3+ of larger size than that of B3+. Decreasing of Vm and Vf can reflect the increase in bridging bonds in the glass network which in turns results in increasing of both Tg and of the investigated compositions.

Effect of K2O Addition on Crystallization and Microstructure of Li2O-ZnO-Al2O3-SiO2 System Glass-Ceramics

2006 ◽  
Vol 11-12 ◽  
pp. 205-208 ◽  
Author(s):  
Z.B. Ke ◽  
An Xian Lu ◽  
G.F. Huang
Keyword(s):  
Electron Microscopy ◽  
Glass Ceramics ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Crystallization Sequence ◽  
Sio2 System ◽  
X Ray ◽  
Three Stages ◽  
Scanning Electron

The Li2O-ZnO-Al2O3-SiO2 system glasses with varying content of K2O were prepared. Crystallization processes of these glasses were investigated using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Microstructure of the glass-ceramics was studied using scanning electron microscopy (SEM). The sequence of crystallization of Li2O-ZnO-Al2O3-SiO2 glasses can be divided into three stages such as crystallization of β1-Li2ZnSiO4, crystallization of Li2Al2Si3O10 and conversion of β1-Li2ZnSiO4 to γ0-Li2ZnSiO4. The K2O content doesn’t vary the crystallization sequence but enhances the crystallization of β1-Li2ZnSiO4. At the same time the introducing of K2O in Li2O-ZnO-Al2O3-SiO2 system hinders the crystallization of Li2Al2Si3O10 and the transformation of β1-Li2ZnSiO4 to the more stable phase γ0- Li2ZnSiO4.

Preparation of Non-Fluorine Glass Ceramics from Modified Molten Blast Furnace Slag

2019 ◽  
Vol 944 ◽  
pp. 1111-1116
Author(s):  
Wen Tao Zhang ◽  
Feng He ◽  
Jun Lin Xie ◽  
Yun Lan Li ◽  
Xiao Qing Liu ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Glass Ceramics ◽  
Stability Index ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Nucleation Agents ◽  
Bf Slag ◽  
Fluorine Glass ◽  
Furnace Slag

Non-fluorine glass ceramics were successfully prepared from modified molten blast furnace (BF) slag. Quartz sand and Al2O3 were added as modification material. Fe2O3, TiO2, and ZrO2 were added as nucleation agents. The thermal properties of the modified BF slag and the structure of glass ceramics were investigated by differential scanning calorimetry (DSC), scanning electron microscope (SEM) and X-ray diffraction analysis (XRD). The results indicated that the crystallization temperature (Tp) decreased with increasing BF slag, and the glass stability index ΔT initially decreased and then increased. As BF slag increased, the growth of akermanite in glass ceramics was enhanced, while the formation of diopside was not notably effected. The micro-hardness of glass ceramics reached 1082 Hv and the flexural strength was 70 MPa when the BF slag was 74 wt. %.

scholarly journals From Structure to Luminescent Properties of B2O3-Bi2O3-SrF2 Glass and Glass-Ceramics Doped with Eu3+ Ions

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4490
Author(s):  
Karolina Milewska ◽  
Michał Maciejewski ◽  
Anna Synak ◽  
Marcin Łapiński ◽  
Aleksandra Mielewczyk-Gryń ◽  
...  
Keyword(s):  
Luminescence Intensity ◽  
Photoelectron Spectroscopy ◽  
Glass Ceramics ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Strontium Fluoride ◽  
Light Emitting ◽  
X Ray ◽  
The Fourier Transform

Glass-ceramics with the composition B2O3-Bi2O3-SrF2 were synthesized by the conventional melt-quenching technique and subsequent crystallization of the parental glasses. The temperature at which the ceramization was carried out was selected based on differential scanning calorimetry (DSC) analysis. The structure of the studied materials and the formation of SrF2 nanocrystals were confirmed by the Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques. It was found that the amount of strontium fluoride introduced into the parental borate-bismuth glass has a significant impact on the growth of SrF2 nanocrystals. In particular, the influence of the crystalline SrF2 phase on luminescence intensity and kinetics was studied using Eu2O3-doped samples. An increase in luminescence intensity was observed in the samples in which SrF2 nanocrystals were formed. This is most likely related to the fact that some of the Eu3+ ions were (after annealing of the glass) located in the crystalline structure of strontium fluoride. This was confirmed both by the luminescence lifetime obtained based on the luminescence decay curves and the calculated Judd–Ofelt parameters, Ω2 and Ω4. The results achieved confirm that the glasses and glass-ceramics described in this work could be considered as a new phosphor for light-emitting diodes (LEDs).

scholarly journals Structural, Thermal and Magnetic Analysis of Fe75Co10Nb6B9 and Fe65Co20Nb6B9 Nanostructured Alloys

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4542
Author(s):  
Albert Carrillo ◽  
Jason Daza ◽  
Joan Saurina ◽  
Lluisa Escoda ◽  
Joan-Josep Suñol
Keyword(s):  
Crystallization Process ◽  
Vibrating Sample Magnetometry ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Rich Phase ◽  
X Ray ◽  
Ferromagnetic Alloys ◽  
Heat Treated ◽  
Magnetic Analysis ◽  
Crystalline Growth

Two nanocrystalline ferromagnetic alloys of the Fe-Co-Nb-B system have been produced by mechanical alloying (MA). Their microstructure, thermal behavior and magnetic response were checked by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and vibrating sample magnetometry (VSM). After 80 h of MA, the alloys were nanostructured (bcc-Fe(Co)-rich phase). As the Co content increases, the density of the dislocations decreases. Besides, a higher concentration of Co causes an increase in the activation energy of the crystallization process. The calculated energies, 267 and 332 kJ/mol, are associated to the crystalline growth of the bcc-Fe-rich phase. The Co content of the samples has no effect on the value of the saturation magnetization, whereas the coercivity is lower in the alloy containing less Co. Samples were compacted and heat-treated. Optimal annealing reduces the coercivity by a factor of two. Results were compared with the data of Fe-Nb-B and Fe-Ni-Nb-B alloys.

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