Crystallization kinetics of amorphous Ga–Sb–Te films: Part II. Isothermal studies by a time-resolved optical transmission method

2004 ◽  
Vol 19 (10) ◽  
pp. 2938-2946 ◽  
Author(s):  
Chain-Ming Lee ◽  
Yeong-Iuan Lin ◽  
Tsung-Shune Chin

Isothermal crystallization kinetics of amorphous Ga–Sb–Te films was studied by means of a time-resolved optical transmission method. Thin films with compositions along the pseudo-binary tie-lines Sb7Te3–GaSb and Sb2Te3–GaSb in the ternary phase diagram were prepared by the co-sputtering method. Crystallization of GaSbTe films reveals a two-stage process: an initial surface nucleation and coarsening (Stage 1) followed by the one-dimensional grain growth (Stage 2). The kinetic exponent (n) value in Stage 1 shows strong dependence on film compositions, while that of Stage 2 is less dependent. The activation energy in Stage 1 increases with increasing GaSb content and reaches the maximum values at compositions close to GaSb, but a decreasing trend was observed in Stage 2. Kinetics parameters between isothermal crystallization of thin films and non-isothermal crystallization of powder samples analyzed by differential scanning colorimetry [J. Mater. Res. 19, 2929 (2004)] are compared. The kinetic parameters in Stage 1 show much correspondence with those of non-isothermal cases in comparable kinetic exponents but with lower activation energies. The discrepancies between nonisothermal and isothermal kinetics are attributed to the sample morphology and the constraint effects.

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 648
Author(s):  
Xiangning Wen ◽  
Yunlan Su ◽  
Shaofan Li ◽  
Weilong Ju ◽  
Dujin Wang

In this work, the crystallization kinetics of poly(ethylene oxide) (PEO) matrix included with poly(ethylene glycol) (PEG) grafted silica (PEG-g-SiO2) nanoparticles and bare SiO2 were systematically investigated by differential scanning calorimetry (DSC) and polarized light optical microscopy (PLOM) method. PEG-g-SiO2 can significantly increase the crystallinity and crystallization temperature of PEO matrix under the non-isothermal crystallization process. Pronounced effects of PEG-g-SiO2 on the crystalline morphology and crystallization rate of PEO were further characterized by employing spherulitic morphological observation and isothermal crystallization kinetics analysis. In contrast to the bare SiO2, PEG-g-SiO2 can be well dispersed in PEO matrix at low P/N (P: Molecular weight of matrix chains, N: Molecular weight of grafted chains), which is a key factor to enhance the primary nucleation rate. In particular, we found that the addition of PEG-g-SiO2 slows the spherulitic growth fronts compared to the neat PEO. It is speculated that the interfacial structure of the grafted PEG plays a key role in the formation of nuclei sites, thus ultimately determines the crystallization behavior of PEO PNCs and enhances the overall crystallization rate of the PEO nanocomposites.


2011 ◽  
Vol 124 (3) ◽  
pp. 2216-2226 ◽  
Author(s):  
Jiunn-Jer Hwang ◽  
Su-Mei Huang ◽  
Hsin-Jiant Liu ◽  
Hawn-Chung Chu ◽  
Li-Huei Lin ◽  
...  

2017 ◽  
Vol 48 (6) ◽  
pp. 2949-2960 ◽  
Author(s):  
Lejun Zhou ◽  
Huan Li ◽  
Wanlin Wang ◽  
Zhaoyang Wu ◽  
Jie Yu ◽  
...  

2021 ◽  
Author(s):  
Zerong Yang ◽  
Raschid Al-Mukadam ◽  
Moritz Stolpe ◽  
Matthias Markl ◽  
Joachim Deubener ◽  
...  

2019 ◽  
Vol 41 (3) ◽  
pp. 394-394
Author(s):  
Zhi Qiang Wang Zhi Qiang Wang ◽  
Yong Ke Zhao and Xiang Feng Wu Yong Ke Zhao and Xiang Feng Wu

The hybrids combined by nano-materials with different dimensions usually possess much better enhancement effects than single one. Graphene oxide-carbon nanotubes hybrids / polyamide 6 composites has been fabricated. The non-isothermal crystallization kinetics of the as-prepared samples was discussed. Research results showed that increasing the cooling rate was in favor of increasing the crystallization rate and the degree of crystallinity for the as-prepared samples. Moreover, the crystallization rate was first decreased and then increased with increasing the hybrids loading. Furthermore, the crystallization mechanism was changed with increasing the crystallization temperature and the cooling rate. The nucleation and growth modes of the non-isothermal crystallization could be classified into three different types, according to the Ozawa’s theory. These complicated results could be attributed to the important role of crystallization rate as well as the simultaneous hindering and promoting effects of the as-prepared hybrids. This work has reference values for understanding the crystallization kinetics of the polyamide 6-based composites.


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