Effects of CaF[sub 2] vis-a-vis TiO[sub 2] as nucleating agent in SiO[sub 2]–Al[sub 2]O[sub 3]–CaO glass-ceramics

2013 ◽  
Author(s):  
Debasis Pradip Mukherjee ◽  
Tanmoy Datta ◽  
Sudip Kumar Das
Keyword(s):  
Glass Ceramics ◽  
Nucleating Agent

The Influence of Blowing Agent on Physical Performance of Porous Glass-Ceramics by Using Waste Glass

2014 ◽  
Vol 953-954 ◽  
pp. 1528-1532
Author(s):  
Chang Wei Xu ◽  
Qi Han Meng ◽  
Yong Chen
Keyword(s):  
Sodium Carbonate ◽  
Apparent Density ◽  
Porous Glass ◽  
Mechanical Performance ◽  
Barium Carbonate ◽  
Glass Ceramics ◽  
Nucleating Agent ◽  
Main Phase ◽  
Blowing Agent ◽  
Powder Density

Use calcium carbonate, sodium carbonate and barium carbonate as blowing agent, polyethylene glycol as binder,Cr2O3as nucleating agent,TiO2as nucleating agent,CaF2as a flux in glass powder, we can produce porous glass-ceramics, and after above research, the apparent density, powder density, porosity, the main phase, microscopic characteristics and thermal performance of the samples would be test. The results show that: considering the physical and mechanical performance of porous glass-ceramics, the froth effect of sodium carbonate is most ideal. When the dosage is 6%, the apparent density is minimum, the porosity is maximum and the thermal conductivity is maximum and the main phase is wollastonite.

Crystallization kinetics and phase formation of Li2O-SiO2-Si3N4 glass-ceramics with P2O5 nucleating agent

2019 ◽  
Vol 786 ◽  
pp. 688-697 ◽  
Author(s):  
Zhiwei Luo ◽  
Haozhang Liang ◽  
Chunchun Qin ◽  
Taoyong Liu ◽  
Anxian Lu
Keyword(s):  
Phase Formation ◽  
Crystallization Kinetics ◽  
Glass Ceramics ◽  
Nucleating Agent

Formation of NaNbO3 Crystals in Dielectric Glass and Glass-Ceramics of a Na2O-Nb2O5-Al2O3-SiO2 System

2008 ◽  
Vol 55-57 ◽  
pp. 229-232 ◽  
Author(s):  
S. Thongsaeng ◽  
Anuson Niyompan ◽  
Rungnapa Tipakontitikul ◽  
Kamonpan Pengpat
Keyword(s):  
Heat Treatment ◽  
Treatment Time ◽  
Glass Ceramics ◽  
Glass Production ◽  
Nucleating Agent ◽  
Aluminum Silicate ◽  
Phase Identification ◽  
Dielectric Glass ◽  
Xrd Patterns ◽  
Glass Compositions

Dielectric glass and glass-ceramics were derived from Na2O-Nb2O5-Al2O3-SiO2 system. Small amount of TiO2 were also introduced into glass compositions to study crystallization behavior of the glass with present of this nucleating agent. Conventional melt-quenching technique was employed for a glass production and the selected bulk glass samples were subjected to the heat-treatment process at appropriate temperature. After six different glass compositions were produced, and by observation with necked eyes, all obtained glass samples are in light brown color and some samples were opaque due to crystallization took place during quenching. Phase identification through XRD patterns show that there were 3 phases, NaNbO3, NaNbO8 and a sodium aluminum silicate compound, found in those opaque glass samples. NaNbO3 is a predominant phase in all samples. Fortunately, clear transparent glass was obtained from the composition with no TiO2 addition. Heat treatment of this glass did not induce phase change, three aforementioned phases still present. Increasing heat treatment time promoted a higher of observed intensity of NaNbO3. But the NaNbO3 crystalline size was not significantly developed with time. The dielectric response of the NaNbO3 crystals in the glass-ceramics samples are influenced by presence of other crystalline phases.

ZrO2-nucleated calcium aluminate glass-ceramics with mid-infrared transparency

2006 ◽  
Vol 21 (2) ◽  
pp. 465-472 ◽  
Author(s):  
Jiin-Jyh Shyu ◽  
Hung-Chuan Mai
Keyword(s):  
Surface Layer ◽  
Calcium Aluminate ◽  
Glass Ceramics ◽  
Nucleating Agent ◽  
Mid Infrared ◽  
Glass Addition ◽  
Parent Glass ◽  
Surface Nucleation ◽  
Bulk Nucleation ◽  
Aluminate Glass

A silica-free MgO–CaO–BaO–Al2O3–ZrO2 glass was converted into glass-ceramic by adding zirconia as a nucleating agent. The crystallization and properties of the glass-ceramics were investigated. It was found that ZrO2 is an efficient nucleating agent for the present calcium aluminate glass. Addition of an appropriate amount of ZrO2 changed the crystallization behavior from surface nucleation to internal nucleation. The primary crystalline phase was Ca3Al2O6, which exhibited bulk nucleation. When the crystallizing time was increased, BaAl2O4 formed as a surface layer that grew from the surface into the interior of the sample. The hardness was increased when the parent glass was converted into glass-ceramics. The glass-ceramics without BaAl2O4 surface layer have visible-to-infrared transparency comparable with the parent glass. The transparency was substantially reduced after the development of the surface layer.

Crystallization Behavior and Optical Properties of Glass-Ceramics Containing Nano-Diopside Crystals

2020 ◽  
Vol 12 (4) ◽  
pp. 510-515
Author(s):  
Byeongguk Kang ◽  
Seunggu Kang
Keyword(s):  
Crystal Growth ◽  
Glass Ceramic ◽  
Crystallization Behavior ◽  
Building Materials ◽  
Red Light ◽  
Glass Ceramics ◽  
Nucleating Agent ◽  
Light Transmittance ◽  
Excitation Light ◽  
Bulk Crystallization

Diopside is a ceramic material with excellent properties including a low dielectric constant, high thermal conductivity, low sintering temperature below 1000 °C, and high mechanical strength. It has been applied to wireless and optical communications, substrates for touch panels, lenses for UV-LED, building materials, and so on. In this study, glass-ceramics containing nano-sized diopside crystals were fabricated, and their transmittance at visible light and photoluminescence were evaluated. In particular, TiO2 was added as a nucleating agent to suppress the surface crystallization phenomenon and Mn was used as a dopant to emit red light. The glass-ceramics were prepared by heat treatment at a temperature lower than the maximum crystal growth temperature (TP) calculated from the non-isothermal analysis method using differential thermal analysis (DTA) for the formation of nano-sized crystals. For glass containing 20 wt% of TiO2, the Avrami constant was calculated to be 2.23 and the activation energy required for crystal growth to be 549 kJ/mol, reflecting typical bulk crystallization behavior. Glass-ceramics with high light transmittance up to 70% were obtained by inducing the bulk crystallization behavior, and the diopside crystal size was less than 10 nm, which was equal to or higher than that of commercialized transparent glass-ceramic products. Glass-ceramic specimens doped with Mn showed luminescence of 736∼766 nm wavelength at excitation light of 365 nm wavelength. The emission peak intensity increased with the amount of dopant added, but gradually decreased with increasing crystallinity of the diopside phase.

scholarly journals Mutual Influence of Special Components in Baotou Steel Blast Furnace Slag on the Crystallization Behavior of Glass

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Yici Wang ◽  
Qi Jiang ◽  
Guoping Luo ◽  
Wenwu Yu ◽  
Yan Ban
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Crystallization Behavior ◽  
Mutual Influence ◽  
Raw Materials ◽  
Glass Ceramics ◽  
Nucleating Agent ◽  
Crystal Phase ◽  
Furnace Slag ◽  
Crystallization Of Glass

In the process of glass-ceramics prepared with Baotou steel blast furnace slag, quartz sand, and other raw materials by melting method, the mutual influence of the special components such as CaF2, REXOY, TiO2, K2O, and Na2O in the blast furnace slag on the crystallization behavior of parent glass was investigated using differential thermal analysis (DTA) and X-ray diffraction (XRD). The results show that the special components in slag can reduce the crystallization temperature and promote crystallization of glass phase, which belongs to surface crystallization of glass, and they cannot play the role of the nucleating agent; the major crystal phase composed of diopside, diopside containing aluminum and anorthite, is slightly different from the expected main crystal phase of diopside. Therefore, the nucleating agents of proper species and quantity must be added into the raw materials in order to obtain glass-ceramics. The results have important theoretical guidance meaning for realizing industrial production of Baotou steel blast furnace slag glass-ceramics preparation.

Manufacture of the Glass-Ceramics from the Lead-Zinc Tailings by Sintering

2014 ◽  
Vol 955-959 ◽  
pp. 2818-2823
Author(s):  
Xue Lian Ou ◽  
Yan Ping Guo ◽  
Gao Hui Zhong ◽  
Bao Qing Li ◽  
Ying Chen ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Crystalline Phase ◽  
Bending Strength ◽  
Orthogonal Experiment ◽  
Glass Ceramics ◽  
Nucleating Agent ◽  
Weight Losses ◽  
Glass Aggregate ◽  
Lead Zinc ◽  
Crystallization Heat

The glass-ceramics of CaO-Al2O3-SiO2system were prepared by sintering using lead-zinc tailings. Orthogonal experiment was carried out to optimize the ratio of lead-zinc tailings, chemical composition of basic-glass and other chemical materials in the system. Crystallization heat treatment conditions were confirmed by the differential thermal analysis (DTA) curve of glass aggregate. Crystalline phase, crystal morphology and mechanical property of the glass-ceramics samples were studied by means of X-ray diffraction (XRD), scanning electron microscope (SEM), hardness and bending strength test. The results indicated that the optimized ratio of the samples was lead-zinc tailings 25%, quartz 46.63%, calcite 21.05%, Al2O310.19% and nucleating agent TiO21%. The optimized crystallization heat treatment was that basic glass was first heated to 800 °C at 10 °C/min, then 800°C-900 °C at 5 °C/min and held still at 900 °C for 2 h. After that, the basic glass was heated to 1230 °C at 1-1.5 °C/min,held for 1h. At last, the glass-ceramics was obtained after the cooling-down of the system. The main crystalline phase of microcrystal glass-ceramics are diopside. The hardness and bending strength were 9.14 GPa and 213.6 MPa, respectively. The glass-ceramics had excellent chemical durability in acid and alkali solution, with weight losses of 0.17% and 0.68%, respectively.

Research on Processing Conditions of CBS Transparent Glass-Ceramics

2013 ◽  
Vol 873 ◽  
pp. 733-736
Author(s):  
Yi Min Wang ◽  
Hong Bo Zhang ◽  
Chun Hui Su ◽  
Qin Lei Wei
Keyword(s):  
Heat Treatment ◽  
Luminescence Property ◽  
Room Temperature ◽  
Glass Ceramics ◽  
Nucleating Agent ◽  
Processing Conditions ◽  
Transparent Glass ◽  
Melting Method ◽  
Heat Treatment Regime ◽  
Precursor Glass

On the basis of experimental verification, the optimum processing conditions of CaO-B2O3-SiO2(CBS) system transparent glass-ceramics were obtained. Composition of main raw powders (wt%) was:CaO 38%,SiO240%,B2O312%.The precursor glass was prepared by melting method and annealed at 560°C for 2h and cooled to room temperature at a speed of 5°C/min.The best nucleating agent is P2O5. The appropriate heat treatment regime to precursor glass was determined to be 2h at 600°C for nucleation and 3h at 780°C for crystallizition.Under this condition,the transmittion of glass-ceramics at the range of visable light is 72% in average and Sm3+keep good luminescence property doped in this host material.

Sign in / Sign up

Export Citation Format

Share Document