نتایج جستجو برای: Crystallization kinetics

تعداد نتایج: 118642  

Journal: :journal of nanostructures 2014
p. alizadeh v. khani

transparent glasses in a system of li2o-mgo-sio2-al2o3-fchemical constituents were prepared by melt quenching method. in the fabrication of nanocrystal glass-ceramics, controlled nucleation and subsequent crystal growth were necessary to avoid loss of transparency. it was therefore important to understand thermal properties and crystallization kinetics of the glass ceramics. the crystallization...

Isothermal melt crystallization kinetics of PVDF was investigated by differential scanning calorimetry. Thin PVDF film has been fabricated by the solvent casting technique using dimethylformamide (DMF). Then, the samples were melted and subsequently crystallized in the range of the crystallization temperature (Tc) between 138 and 145 °C. The crystallization kinetics was derived from Avrami equa...

Journal: :علوم و تکنولوژی پلیمر 0
محمد رضوی نوری

non-isothermal crystallization kinetics of polypropylene (pp) and pp containing 0.5 wt% singlewalled carbon nanotubes (pp/swnt) were studied at various cooling rates using differential scanning calorimetry technique. the non-isothermal melt crystallization data were analyzed according to ozawa and cazé-chuah models. although ozawa model was successful in describing the nonisothermal crystalliza...

2015
Sungwoo Sohn Yeonwoong Jung Yujun Xie Chinedum Osuji Jan Schroers Judy J. Cha

Atomistic understanding of crystallization in solids is incomplete due to the lack of appropriate materials and direct experimental tools. Metallic glasses possess simple metallic bonds and slow crystallization kinetics, making them suitable to study crystallization. Here, we investigate crystallization of metallic glass-forming liquids by in-situ heating metallic glass nanorods inside a transm...

2002
A. Hsiao M. E. McHenry D. E. Laughlin M. J. Kramer C. Ashe T. Ohkubo

The characterization of the crystallization kinetics of an amorphous soft magnetic alloy, Fe88Zr7B4Cu1, called NANOPERM, is presented. Vibrating sample magnetometry (VSM), X-ray diffractometry, and differential scanning calorimetry have been used to observe crystallization kinetics. The VSM observations take advantage of the Curie temperature of the amorphous phase c amorphous of the NANOPERM a...

2013
Purwiyatno Hariyadi Eko Hari Purnomo Nuri Andarwulan Dedi Fardiaz

It has been shown experimentally by many researchers that cooling rate and crystallization temperature affect the rate of crystal formation. In this study, crystallization kinetics of coconut oil was measured by monitoring the solid fraction of the oil using pulsed Nuclear Magnetic Resonance (pNMR). Four levels of cooling rate and crytallization temperature were studied. Parameters of crystalli...

2011
Mohd Nasir Mohd Abdul Majeed Khan Mushahid Husain Mohammad Zulfequar

The crystallization process in Se100–xZnx glassy system is investigated using differential scanning calorimeters (DSC). The samples are prepared by conventional melt-quenching technique in the composition range 2 ≤ x ≤ 20 (at%). Nonisothermal measurements are carried out for different heating rates .The value of the glass transition temperature Tg the crystallization temperature Tc and the crys...

2016
Dongwoo Lee Bingge Zhao Eric Perim Haitao Zhang Pan Gong Yulai Gao Yanhui Liu Cormac Toher Stefano Curtarolo Jan Schroers Joost J. Vlassak

We have investigated the crystallization kinetics of Cu50Zr50 metallic glass thin films using nanocalorimetry. The crystallization process is growth-controlled during heating and nucleation-controlled during cooling, resulting in different critical heating and cooling rates to suppress crystallization. Measurements over a wide range of scanning rates (13 K/s to 21,000 K/s) reveal that crystalli...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2003
Dimiter N Petsev Kai Chen Olga Gliko Peter G Vekilov

For critical tests of whether diffusion-limited kinetics is an option for the solution-solid phase transition of molecular substances or whether they are determined exclusively by a transition state, we performed crystallization experiments with ferritin and apoferritin, a unique pair of proteins with identical shells but different molecular masses. We find that the kinetic coefficient for crys...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2007
amir abbas izadpanah mohsen vafaie sefti farshad varaminian

based on driving force for crystallization of one-component gas hydrate, in this report an expression for the supersaturation for crystallization of multicomponent gas hydrate is derived. expressions for the supersaturation are obtained in isothermal and isobaric regimes. the results obtained are applied to the crystallization of hydrates of mixtures of methane plus ethane and can apply to othe...

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