Crystallization Behavior and Kinetics of Lithium Aluminosilicate Glasses with Various Li2O Contents

2021 ◽  
Vol 36 (2) ◽  
pp. 243-247
Author(s):  
Jianjun Han ◽  
Wei Hong ◽  
Hong Jiang ◽  
Jianxiong He ◽  
Qianchen Wang ◽  
...  
Keyword(s):  
Crystallization Behavior ◽  
Lithium Aluminosilicate ◽  
Aluminosilicate Glasses ◽  
Kinetics Of

scholarly journals Melt Crystallization Behavior and Crystalline Morphology of Polylactide/Poly(ε-caprolactone) Blends Compatibilized by Lactide-Caprolactone Copolymer

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1181 ◽  
Author(s):  
Chunmei Zhang ◽  
Qiaofeng Lan ◽  
Tianliang Zhai ◽  
Shengqiang Nie ◽  
Jun Luo ◽  
...  
Keyword(s):  
Crystallization Behavior ◽  
Crystallization Time ◽  
Half Time ◽  
Melt Crystallization ◽  
Crystalline Morphology ◽  
Casting Method ◽  
Three Samples ◽  
Significant Difference ◽  
Compatibilization Effect ◽  
Kinetics Of

Lactide-Caprolactone copolymer (LACL) was added to a Polylactide/Poly(ε-caprolactone) (PLA/PCL) blend as a compatibilizer through solution mixing and the casting method. The melt crystallization behavior and crystalline morphology of PLA, PLA/PCL, and PLA/PCL/LACL were investigated using differential scanning calorimeter (DSC) and polarized optical microscopy (POM), respectively. The temperature of the shortest crystallization time for the samples was observed at 105 °C. The overall isothermal melt crystallization kinetics of the three samples were further studied using the Avrami theory. Neat PLA showed a higher half-time of crystallization than that of the PLA/PCL and PLA/PCL/LACL blends, whereas the half-time of crystallization of PLA/PCL and PLA/PCL/LACL showed no significant difference. The addition of PCL decreased the spherulite size of crystallized PLA, and the nuclei density in the PLA/PCL/LACL blend was much higher than that of the PLA and PLA/PCL samples, indicating that LACL had a compatibilization effect on the immiscible PLA/PCL blend, thereby promoting the nucleation of PLA. The spherulites in the PLA/PCL and PLA/PCL/LACL blend exhibited a smeared and rough morphology, which can be attributed to the fact that PCL molecules migrated to the PLA spherulitic surface during the crystallization of PLA.

The Effect of Acidity Coefficient on Crystallization Behavior of Blast Furnace Slag Fibers

2018 ◽  
Vol 37 (1) ◽  
pp. 33-37
Author(s):  
Tie-Lei Tian ◽  
Yu-Zhu Zhang ◽  
Hong-wei Xing ◽  
Jie Li ◽  
Zun-Qian Zhang
Keyword(s):  
Thermal Stability ◽  
Crystallization Kinetics ◽  
Blast Furnace Slag ◽  
Chemical Structure ◽  
Crystallization Behavior ◽  
Three Dimensional ◽  
Mineral Wool ◽  
Mineral Wool Fiber ◽  
Kinetics Of ◽  
Furnace Slag

AbstractThe chemical structure of mineral wool fiber was investigated by using Fourier Transform Infrared Spectroscopy (FTIR). Next, the glass transition temperature and the crystallization temperature of the fibers were studied. Finally, the crystallization kinetics of fiber was studied. The results show that the chemical bond structure of fibers gets more random with the increase of acidity coefficient. The crystallization phases of the fibers are mainly melilites, and also a few anorthites and diopsides. The growth mechanism of the crystals is three dimensional. The fibers with acidity coefficient of 1.2 exhibit the best thermal stability and is hard to crystallize as it has the maximum aviation energy of crystallization kinetics.

Studies on SiBN(C)-ceramics: Oxidation- and Crystallization Behavior Lead the Way to Applications

1994 ◽  
Vol 346 ◽  
Author(s):  
H.-P. Baldus ◽  
G. Passing
Keyword(s):  
Crystallization Behavior ◽  
Bulk Material ◽  
Single Source ◽  
Single Source Precursor ◽  
High Oxidation ◽  
C And N ◽  
High Oxidation Resistance ◽  
Kinetics Of ◽  
Very High ◽  
Thermal Stability Of

ABSTRACTThe thermal stability of amorphous borosilicon nitride (Si3B3N7) and borosilicon carbonitride (SiBN3C) between 1000°C and 2000oC both in air and under inert conditions is reported. Both materials are derived from polymerization and subsequent pyrolysis of a “single source” precursor. On heating in vacuum or nitrogen SiBN3C remains amorphous up to lCWC whereas Si3B3N7 crystallizes at about 1800°C under these conditions. At about 2000^ the SiBN(C)-materials decompose into SiC, BN, B4C and N2.Oxidation studies performed by TEM- and SEM-investigations of oxidized borosilicon carbonitride grains reveal that an interlayer consisting of B, N, and only little O is formed between the oxide scale on the surface and the inner bulk material. The interlayer does not disappear at temperatures above 1450°C in contrast to the Si2N20-interiayer observed on oxidized silicon nitride. The oxidation kinetics of the new ceramics are established in the range from 1000°C to 1600°C indicating a very high oxidation resistance. Possible applications as matrix materials as well as materials for fibers and coatings are discussed.

scholarly journals Crystallization kinetics of BaO–Al2O3–SiO2 glasses

1989 ◽  
Vol 4 (5) ◽  
pp. 1257-1265 ◽  
Author(s):  
Narottam P. Bansal ◽  
Mark J. Hyatt
Keyword(s):  
High Temperature ◽  
Ceramic Composites ◽  
X Ray Diffraction ◽  
Aluminosilicate Glasses ◽  
Structural Applications ◽  
Barium Aluminosilicate ◽  
Kinetics Of ◽  
High Temperature Polymorph ◽  
Large Volume Change ◽  
Glass Compositions

Barium aluminosilicate glasses are being investigated as matrix materials in high-temperature ceramic composites for structural applications. Kinetics of crystallization of two refractory glass compositions in the barium aluminosilicate system have been studied by differential thermal analysis (DTA), x-ray diffraction (XRD), and scanning electron microscopy (SEM). From variable heating rate DTA, the crystallization activation energies for glass compositions (wt. %) 10BaO–38Al2O3–51SiO2–1MoO3 (glass A) and 39BaO–25Al2O3–35SiO2–1MoO3 (glass B) were determined to be 553 and 558 kJ/mol, respectively. On thermal treatment, the crystalline phases in glasses A and B were identified as mullite (3Al2O3 · 2SiO2) and hexacelsian (BaO · Al2O3 · 2SiO2), respectively. Hexacelsian is a high-temperature polymorph which is metastable below 1590 °C. It undergoes structural transformation into the orthorhombic form at ∼300 °C accompanied by a large volume change which is undesirable for structural applications. A process needs to be developed where stable monoclinic celsian, rather than hexacelsian, precipitates out as the crystal phase in glass B.

Optical Properties and Phase Transformation Kinetics of Ge-Sb-Te-(N) Alloy Thin Films Investigated by Ellipsometry

2003 ◽  
Vol 803 ◽  
Author(s):  
Sang Youl Kim
Keyword(s):  
Thin Films ◽  
Phase Transformation ◽  
Optical Properties ◽  
Phase Change ◽  
Crystallization Behavior ◽  
Ex Situ ◽  
Recent Analysis ◽  
Avrami Equation ◽  
Step Process ◽  
Kinetics Of

ABSTRACTThe recent research works of optical properties and crystallization kinetics of phase change Ge-Sb-Te-(N) alloy by using ellipsometry are reviewed.The complex refractive index spectra of phase-change Ge2Sb2+xTe5 thin films and those of the nitrogen Ge2Sb2Te5 thin films have been determined.The crystallization behavior of amorphous Ge2Sb2Te5 thin films investigated by in situ ellipsometry revealed that the crystallization process of Ge2Sb2Te5 near 140°C is a two-step process. The kinetic exponent of the Johnson-Mehl-Avrami equation was about 4.4 for the first stage and 1.1 for the second stage. Ex situ study confirmed the cascaded crystallization behavior of phase-change Ge2Sb2Te5 films.A passive type single wavelength ellipsometer adopting a DOAP (division-of-amplitude photopolarimeter) configuration with nanosecond time resolution is developed to monitor the phase transformation of Ge2Sb2Te5 caused by a high power nanosecond laser pulse in real time. The two-step process - the fast nucleation-dominant stage followed by the slow anomalous grain growth stage is confirmed.Based on the recent analysis of the ellipsometric isotherm at moderately elevated temperature, we found for the first time that the fast nucleation dominant crystallization of Ge2Sb2Te 5 can be better explained by a modified JMA equation that illustrates the nucleation dominated process where the creation rate of a new nucleus is proportional to the density of preexisting nuclei and growth rate is negligible.

Non-Isothermal Crystallization Behavior and Kinetics of Compatibilized β Nucleated Polypropylene/Polystyrene Blends

2014 ◽  
Vol 893 ◽  
pp. 291-294 ◽  
Author(s):  
Hu Bin Lin ◽  
Chong Ming Du ◽  
Jian Yi Zhu ◽  
Wen Yao Liang
Keyword(s):  
Block Copolymer ◽  
Block Copolymers ◽  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Melting Behavior ◽  
Ethylene Propylene ◽  
Crystallization Characteristic ◽  
Different Content ◽  
Kinetics Of

The β nucleated polypropylene (PP), uncompatibilized β nucleated PP/polystyrene (PS) and compatibilized β nucleated PP/PS blends were prepared on a twinscrew extruder.and added into compatibilizers styrene-ethylene-propylene block copolymer (SEP) or two styrene-ethylene-butylen- e-styrene block copolymers (SEBS) with different content of styrene.The crystallization characteristic, melting behavior and crystallization kinetics of these composites were studied.

Kinetic Study on Phosphate Enrichment Behavior in CaO–SiO2–FeO–Fe2O3–P2O5 Steelmaking Slags

2018 ◽  
Vol 37 (5) ◽  
pp. 477-486
Author(s):  
Jin-yan Li ◽  
Mei Zhang ◽  
Min Guo ◽  
Xue-min Yang
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Crystallization Behavior ◽  
Crystallization Rate ◽  
Avrami Equation ◽  
One Dimensional ◽  
Thermal Crystallization ◽  
Steelmaking Slags ◽  
Cooling Schedules ◽  
Kinetics Of

AbstractThe iso-thermal crystallization behavior of phosphate-enriched phase has been experimentally investigated in the rapidly quenched CaO–SiO2–FeO–Fe2O3–P2O5 steelmaking slags under different cooling schedules. The experimental results indicate that increasing endpoint temperature from 1453 to 1533 K and prolonging holding time from 2 to 60 min can result in an increasing tendency of the size of phosphate-enriched phase in the shape of one-dimensional rod. The crystallization kinetics of phosphate-enriched phase in steelmaking slags has been described by Avrami equation. The Avrami constant $$n$$ was obtained to be 0.472, while the crystallization rate constant $$k$$ was recommended as $$\ln k{\rm{= 57}}{\rm{. 40 + 12,273}}{\rm{. 96}}/T - {\rm{8}}{\rm{. 25}}\,\ln T - {\rm{5}}{\rm{. 5}\times{\rm 10}^{- 3}}T$$. Thus, the apparent activation energy $$E$$ of crystallization is recommended as $$E{\rm{= 537}}{\rm{. 60}} - {\rm{206}}{\rm{. 015}}T$$ kJ/mol.

Sign in / Sign up

Export Citation Format

Share Document