Journal articles: 'Crystallization curves'

1

Kapnistos, M., and D. Vlassopoulos. "Rheological Master Curves of Crystallizing Polymer Mixtures." Applied Rheology 16, no. 3 (June 1, 2006): 132–35. http://dx.doi.org/10.1515/arh-2006-0008.

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Abstract We present a simple methodology for extending linear viscoelastic measurements of crystallizing polymers to the high-frequency regime, where usually crystallization kinetics represents an obstacle. The idea is to perform rapid quenches, below the melting temperature (which corresponds to the high-frequency region), account for the thermal equilibration and the very slow early stages of crystallization, and perform the measurements before really crystallization sets in, in the “quasi-equilibrium” state. Albeit tedious, when properly done, this method works remarkably well, as demonstrated for a particular polybutadiene mixture, and opens the route for obtaining rheological master curves in a wide variety of crystallizing polymers.

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2

Lambrigger, Markus. "Avrami Master Curves for Isothermal Polymer Crystallization." Polymer Journal 29, no. 2 (February 1997): 188–89. http://dx.doi.org/10.1295/polymj.29.188.

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Plummer, C. J. G., and H. H. Kausch. "DSC non-isothermal crystallization curves in polyoxymethylene." Colloid & Polymer Science 273, no. 3 (March 1995): 227–32. http://dx.doi.org/10.1007/bf00657828.

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Regulski, Krzysztof, Dorota Wilk-Kołodziejczyk, Tomasz Szymczak, Grzegorz Gumienny, Zenon Pirowski, Krzysztof Jaśkowiec, and Stanisława Kluska-Nawarecka. "Data Mining Methods for Prediction of Multi-Component Al-Si Alloy Properties Based on Cooling Curves." Journal of Materials Engineering and Performance 28, no. 12 (November 18, 2019): 7431–44. http://dx.doi.org/10.1007/s11665-019-04442-z.

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AbstractThe paper concerns the mechanical properties of hypoeutectic Al-Si alloy (silumin) with the addition of Cr, Mo, V and W. Changes in microstructure under the impact of these elements result in a change in the mechanical properties. Crystallization of Al-Si alloys determines grain size reduction, which causes a significant increase in their strength properties. Crystallization subjected to modifications through the influence of alloying additives can be described by the cooling curve run. Statistical relationships between the characteristic values of cooling curves and mechanical properties are investigated with data mining techniques of regression, especially regression trees. Such knowledge could provide an ability of a property prediction on the basis of cooling curves in terms of the benefits of a short time of the curve registration.

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Kelly, Catherine A., and Mike J. Jenkins. "Modeling the crystallization kinetics of polymers displaying high levels of secondary crystallization." Polymer Journal 54, no. 3 (November 19, 2021): 249–57. http://dx.doi.org/10.1038/s41428-021-00581-0.

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AbstractThe isothermal crystallization of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) was evaluated using a range of models, namely, Avrami, simplified Hillier, Tobin, Malkin, Urbanovici–Segal, Velisaris–Seferis, and Hay. Two methods of model evaluation were used: determination of the parameters through traditional double log plots and curve fitting via nonlinear, multivariable regression. Visual inspection of the cumulative crystallization curves, calculation of the R2 value and standard error of the regression, and evaluation of the returned parameters were used to assess which model best describes the experimental data. The Hay model was found to generate the best fit, closely followed by the Velisaris–Seferis parallel model, suggesting that primary and secondary crystallization occur concurrently. The Avrami, Malkin, and Tobin models were found to perform well when the data is restricted to the region where primary crystallization dominates; however, they could not be used to successfully model the entire crystallization process. This work highlights the importance of selecting the most appropriate model for analyzing kinetics, especially when high levels of lamellar thickening and infilling occur during crystallization.

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Zhang, Jie, Fa-Xue Li, and Jiang-Yong Yu. "Non-isothermal crystallization behavior of biodegradable poly(butylene succinate-co-terephthalate) (PBST) copolyesters." Thermal Science 16, no. 5 (2012): 1480–83. http://dx.doi.org/10.2298/tsci1205480z.

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Non-isothermal crystallization and subsequent melting of biodegradable poly(bu-tylene succinate-co-terephthalate) copolyesters with different butylene terephtha-late contents were investigated by differential scanning calorimetry measurements. Differential scanning calorimetry crystallization curves revealed that butylene terephthalate contents of poly(butylene succinate-co-terephthalate) copolyesters had an identical effects on the onset, peak and final crystallization temperatures. Subsequent differential scanning calorimetry melting curves implied that both PBST-10 and PBST-70 copolyesters had the narrow distribution of lamellar thickness, while the PBST-50 copolyester showed much wider distribution.

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Adiguzel, Vedat, Wei Liu, Asadullah Memon, Hongtao Zhou, Imran Akbar, Atif Zafar, and Ubedullah Ansari. "Solid-liquid phase equilibria of (H2O-Mn(H2PO2)2-MnCl2-NaCl), (H2O-Mn(H2PO2)2-MnCl2) and (H2O-NaCl- MnCl2) systems at 323.15 K." Journal of the Serbian Chemical Society, no. 00 (2020): 59. http://dx.doi.org/10.2298/jsc200521059a.

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The solid-liquid phase equilibria (SLE) and densities of H2O-NaCl- -MnCl2-Mn(H2PO2)2 quaternary system, H2O-NaCl-MnCl2 and H2O-MnCl2- -Mn(H2PO2)2 ternary systems were investigated at 323.15 K by the isothermal solution saturation method. The analyses of the liquid and solid phases were used to determine the composition of the solid phase using the Schreinemakers graphic method. The ternary systems contain one invariant point, two invariant curves and two crystallization regions. In the quaternary system, there is one invariant point, three invariant curves, and three crystallization areas corresponding to NaCl, MnCl2 4H2O, and Mn(H2PO2)2H2O. The crystallization area of Mn(H2PO2)2 H2O, being the largest in comparison with those of other salts, occupied 80.75 % of the total crystallization area.

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Liu, Chen, Kang Zheng, Xia Yin Yao, Xian Zhang, Xiang Lan Liu, Ruo Xi Wang, and Xing You Tian. "The Melting and Recrystallization Behavior of Poly(ethylene Terephthalate)/SiO₂ Nanocomposites Studied by Step-Scan DSC." Advanced Materials Research 87-88 (December 2009): 69–73. http://dx.doi.org/10.4028/www.scientific.net/amr.87-88.69.

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The melting and recrystallization behavior of Poly(ethylene terephthalate) (PET)/SiO2 nanocomposites after isothermal crystallization from the melt was studied by Step-scan differential scanning calorimetry (SDSC). The influence of SiO2 contents, crystallization temperature and crystallization time on the melting process were examined. Two melting endotherms(in the SDSC CP.A curves, reversible part) and one recrystallization exotherm (in the SDSC CP.IsoK curves, irreversible part)of PET/SiO2 nanocomposites after isothermal crystallization were observed during the melt process. This ascribes to the melting-recrystallization mechanism .The low temperature endotherm attributes to the melting of primary crystal formed during the isothermal treating and the high temperature endotherm resulting from the melting of recrystallization materials. The reason why more recrystallization happened with the increase of SiO2 content was given and the process of recrystallization was described in detail. The effects of crystal perfection and recrystallization were minimized by increasing of crystallization temperature and time.

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9

Lambrigger, Markus. "Non-isothermal polymer crystallization kinetics and Avrami master curves." Polymer Engineering & Science 38, no. 4 (April 1998): 610–15. http://dx.doi.org/10.1002/pen.10225.

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10

Liu, Chen, Xiang Hui Lu, Xue Qi, and Peng Li. "The Melting Behavior of Poly(Ethylene Terephthalate)/ Attapulgite Nanocomposites." Advanced Materials Research 773 (September 2013): 530–33. http://dx.doi.org/10.4028/www.scientific.net/amr.773.530.

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The melting and recrystallization behavior of Poly(ethylene terephthalate) (PET)/ Attapulgite(At)nanocomposites after isothermal crystallization from the melt was studied by Step-scan differential scanning calorimetry (SDSC). The influence of At contents, crystallization temperature and crystallization time on the melting process were examined. Two melting endotherms(in the SDSC CP.A curves, reversible part) and one recrystallization exotherm (in the SDSC CP.IsoK curves, irreversible part)of PET/At nanocomposites after isothermal crystallization were observed during the melt process. This ascribes to the melting-recrystallization mechanism .The low temperature endotherm attributes to the melting of primary crystal formed during the isothermal treating and the high temperature endotherm resulting from the melting of recrystallization materials. The reason why more recrystallization happened with the increase of At content was given and the process of recrystallization was described in detail. The effects of crystal perfection and recrystallization were minimized by increasing of crystallization temperature and time.

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Keridou, Ina, Luis J. del Valle, Lutz Funk, Pau Turon, Ibraheem Yousef, Lourdes Franco, and Jordi Puiggalí. "Isothermal Crystallization Kinetics of Poly(4-hydroxybutyrate) Biopolymer." Materials 12, no. 15 (August 6, 2019): 2488. http://dx.doi.org/10.3390/ma12152488.

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Thermal properties and crystallization kinetics of poly(4-hydroxybutyrate) (P4HB) have been studied. The polymer shows the typical complex melting behavior associated to different lamellar populations. Annealing processes had great repercussions on properties and the morphology of constitutive lamellae as verified by X-ray scattering data. Kinetics of isothermal crystallization was evaluated by both polarizing optical microscopy (POM) and calorimetric (DSC) measurements, which indicated a single crystallization regime. P4HB rendered banded spherulites with a negative birefringence when crystallized from the melt. Infrared microspectroscopy was applied to determine differences on the molecular orientation inside a specific ring according to the spherulite sectorization or between different rings along a determined spherulitic radius. Primary nucleation was increased during crystallization and when temperature decreased. Similar crystallization parameters were deduced from DSC and POM analyses (e.g., secondary nucleation parameters of 1.69 × 105 K2 and 1.58 × 105 K2, respectively). The effect of a sporadic nucleation was therefore minimized in the experimental crystallization temperature range and a good proportionality between overall crystallization rate (k) and crystal growth rate (G) was inferred. Similar bell-shaped curves were postulated to express the temperature dependence of both k and G rates, corresponding to the maximum of these curves close to a crystallization temperature of 14–15 °C.

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Zhuang, Wei, and Yu Lei Du. "Crystallization Behavior of Mg₆₀Ni_23.6La_16.4 Metallic Glass." Advanced Materials Research 476-478 (February 2012): 85–88. http://dx.doi.org/10.4028/www.scientific.net/amr.476-478.85.

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Mg60Ni23.6La16.4 amorphous ribbon was prepared by melting-spinning method and the crystallization behavior was investigated by differential scanning calorimetry (DSC). The Mg60Ni23.6La16.4 crystallization process exhibits two stages of crystallization and shows an obviously kinetic nature. Isothermal DSC curves indicate that the crystallization is a nucleation-and-growth procedure. The activation energy analysis based on Kissinger Method shows that the growth process for the first crystallization procedure is more difficult than that for the second one. Calculation based on the Johnson-Mehl-Avrami (JMA) model shows that the primary crystallization starts from small crystalline grains with an increasing nucleation rate.

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13

Osetskyi, Oleksandr, Tetyana Gurina, Anna Poliakova, and Stanislav Sevastianov. "Thermoplastic Analysis of Cluster Crystallization of Cryoprotective Solutions." Problems of Cryobiology and Cryomedicine 31, no. 3 (September 25, 2021): 203–13. http://dx.doi.org/10.15407/cryo31.03.203.

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For the first time the possibility of using thermomechanical analysis to construct the fragments of state diagrams of cryoprotective solutions in the zone of glass transition temperatures has been considered. A method for studying cluster crystallization of cryoprotective solutions based on thermomechanical curves has been developed. The parameters of thermomechanical curves of frozen aqueous solutions of dimethyl sulfoxide (DMSO), polyethylene oxide 1500 (PEO-1500), glycerol were analyzed and the relationship between these parameters and the cluster crystallization kinetics for these solutions was established. On the basis of experimentally obtained thermomechanical curves for the frozen solutions of DMSO and PEO-1500 the possibility of formation of clusters of two types has been shown: on the basis of ice and cryoprotective substance microcrystals. Additional experimental data were obtained to construct a complete state diagrams of cryoprotective solutions, which include the existing cluster phase areas.

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14

Fang, Yong Zheng, Jia Yue Xu, Zhang Yong Wang, and Hui Chun Qian. "Surface and Bulk Crystallization Kinetics of Er³⁺ Doped Mixed Alkali Phosphate Glasses." Advanced Materials Research 146-147 (October 2010): 1142–46. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.1142.

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DSC measurements have been carried out for the as-quenched xNa2O- (15-x)Li2O-4B2O3-11Al2O3-5BaO-65P2O5 (x=0,3.75,7.5,11.25 and 15 mol%) glasses with different particle size. Two crystallization peaks appear on the DSC curves for sample sized 90-110μm. The presence of two crystallization peaks is due to different crystallization mechanisms, surface and bulk (internal) crystallization. The X-ray diffraction measurements are also employed to investigate the crystallization of glasses. The results show that bulk crystallization is difficult to occur in the studied phosphate glasses. The effect of mixed alkali on glass thermal stability is also studied in this paper. The surface and bulk crystallization active energies are calculated according to Kissinger equation.

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Johnson, Bradley R., and Waltraud M. Kriven. "Crystallization kinetics of yttrium aluminum garnet (Y3Al5O12)." Journal of Materials Research 16, no. 6 (June 2001): 1795–805. http://dx.doi.org/10.1557/jmr.2001.0248.

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The kinetics and pathways for crystallization of solid, amorphous, yttrium aluminum garnet (YAG) were studied using isothermal differential thermal analysis, x-ray diffraction, and transmission electron microscopy. The activation energy for crystallization was 437 KJ/mol and the measured Avrami exponent was 2.74, which corresponded to three-dimensional crystal growth with a constant number of nuclei. Time–temperature–transformation (T–T–T) curves were developed from the data to predict crystallization rates as a function of temperature. The crystallization pathway for YAG in this system is compared to others reported in the literature.

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Ren, Yueqing, Suhe Zhao, Qian Yao, Qianqian Li, Xingying Zhang, and Liqun Zhang. "Effects of plasticizers on the strain-induced crystallization and mechanical properties of natural rubber and synthetic polyisoprene." RSC Advances 5, no. 15 (2015): 11317–24. http://dx.doi.org/10.1039/c4ra13504k.

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Studnicki, A., M. Gromczyk, M. Kondracki, J. Suchoń, and J. Szajnar. "Primary Crystallization Studies and Abrasion Analysis of Cr-Ni-Mo Cast Steel." Archives of Foundry Engineering 15, no. 4 (December 1, 2015): 75–80. http://dx.doi.org/10.1515/afe-2015-0083.

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Abstract The article shows results of studies of primary crystallization and wear resistance of Cr-Ni-Mo cast steel intended for work in corrosive and abrasive conditions. The studies of primary crystallization were conducted with use of TDA method and modified tester allowing measurement casting cooling time influence on the cooling and crystallization curves of studied alloys. After heat treatment of examined cast steel wear tests of the samples were conducted on pin-on-disc type device.

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Bansal, B., and H. Mu¨ller-Steinhagen. "Crystallization Fouling in Plate Heat Exchangers." Journal of Heat Transfer 115, no. 3 (August 1, 1993): 584–91. http://dx.doi.org/10.1115/1.2910728.

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Crystallization fouling of calcium sulfate was investigated in a plate and frame heat exchanger. The effects of flow velocity, wall temperature, and CaSO4, concentration on the fouling rates have been investigated and the distribution of scale along the heat transfer surface has been observed. The measured fouling curves are compared with predictions from a surface reaction controlled model.

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Sevilay DEM RC, Sevilay DEM RC, Vedat ADIG ZEL Vedat ADIG ZEL, and mer SAH N. and Hasan ERGE mer SAH N and Hasan ERGE. "Ternary SLE Measurements for the Systems H2O+ZnCl2+Zn(H2PO2)2 at T= (298, 313 and 333) K." Journal of the chemical society of pakistan 44, no. 1 (2022): 27. http://dx.doi.org/10.52568/000984/jcsp/44.01.2022.

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The solid-liquid equilibrium (SLE) of H2O+ZnCl2+Zn(H2PO2)2 ternary system at 298, 313 and 333 K have been studied with the use of isothermal method. Solid phase compositions have been determined with Schreinemaker’s method. H2O+ZnCl2+Zn(H2PO2)2 ternary systems have simple eutectic type in 298, 333K. One invariant point, two invariant curves and two crystallization region have been observed in the phase diagrams at 298, 333K. Otherwise, One invariant point, three invariant curves and two crystallization region have been observed in the phase diagrams in 313K. In the crystallization regions; (i) Zn(H2PO2).H2O and ZnCl2, (ii) Zn(H2PO2)2, Zn(H2PO2).H2O and ZnCl2, (iii) Zn(H2PO2)2 and ZnCl2 salts have been observed at 298 K, 313K, and 333 K, respectively. In H2O+ZnCl2+Zn(H2PO2)2 ternary system, the increasing salting-out effect of Zn(H2PO2)2 on ZnCl2 with temperature.

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Liu, Xiongjun, Xidong Hui, and Guo Liang Chen. "Crystallization Kinetics of Zr₆₅Ni₂₅Ti₁₀ Metallic Glass Alloy." Materials Science Forum 475-479 (January 2005): 3385–88. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.3385.

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The crystallization reaction of Zr65Ni25Ti10 (at. %) metallic glass was studied by using differential scanning calorimetry (DSC) at constant heating rate. Two distinct exothermic peaks were observed from the continuous heating DSC curves, implying the crystallization process undergoes two different stages. The crystallization kinetic parameters, including activation energy (E), Avrami exponent (n) and frequency factor (K0), were determined with non-isothermal analysis method based on the DSC data. The values of E are 267.353 KJ/mol and 224.293 KJ/mol, n 4.0±0.1 and 6.8±0.1, K0 4.4±0.05E+20 and 2.0±0.08E+15, for the first and second crystallization stage, respectively. The results suggest that the crystallization mechanism is governed dominantly by interface controlled growth with constant nucleation rate for the first crystallization stage and with increasing nucleation rate for the second stage.

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Zhang, Ru Guo, Hong Zhang, Zheng Zhang, Hua Zheng, Ying Feng, and Wen Wen Zhang. "Characterization of Five Natural Resins and Waxes by Differential Scanning Calorimetry (DSC)." Advanced Materials Research 418-420 (December 2011): 643–50. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.643.

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Thermal properties of 5 natural resin and wax samples (shellac, rosin, shellac wax, beeswax, Chinese insect wax) were examined by differential scanning calorimetry (DSC). The DSC melting and crystallization curves of the samples were presented in this paper. Three DSC parameters, To, Tf and ΔT (difference between To and Tf), were selected from each curve. Evaluation results of the parameters showed that they were statistically significant with individual excellent reproducibility. Information was provided by evaluation of changes among thermal absorption or release peaks of the curves in differentiating the five resins and waxes. It was demonstrated in this paper that DSC is rapid, convenient, reliable and accurate to qualitatively identify the resins and waxes mentioned above.

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Xiao, Hua Xing. "A Simple Method for Identification of the Alloy’s Non-Crystalline Structure." Key Engineering Materials 567 (July 2013): 3–7. http://dx.doi.org/10.4028/www.scientific.net/kem.567.3.

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In the thermomagnetism analysis, the ferromagnetic amorphous alloy near or after the Curie temperature within a certain scope was in the paramagnetic condition with low magnetization. When the heating temperature achieved the crystallization temperature of the amorphous alloy, the magnetization increased significantly due to the crystallization of the alloy. As the obvious crystallization of the amorphous alloy, the crystallization phase with a high Curie temperature (Tc) formed and the ferromagnetism of the alloy would not be fully transferred to paramagnetism. The magnetization of the alloy would maintain at a stable high level before it had been fully crystallized. Therefore, the structure of the ferromagnetic amorphous alloy can be identified accurately by the obvious difference between the thermomagnetism curves before and after crystallization.

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Gough, Terry, and Reinhard Illner. "Modeling Crystallization Dynamics when the Avrami Model Fails." VLSI Design 9, no. 4 (January 1, 1999): 377–83. http://dx.doi.org/10.1155/1999/38517.

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Recent experiments on the formation of crystalline CO2 from a newly discovered binary phase consisting of CO2 and C2H2 at 90° K fail to be adequately simulated by Avrami equations. The purpose of this note is to develop an alternative to the Avrami model which can make accurate predictions for these experiments. The new model uses empirical approximations to the distribution densities of the volumes of three-dimensional Voronoi cells defined by Poisson-generated crystallization kernels (nuclei). Inside each Voronoi cell, the growth of the crystal is assumed to be linear in diameter (i.e., cubic in volume) until the cell is filled by the CO2 crystals and the C2H2 (thought of as a waste product). The cumulative growth curve is computed by averaging these individual growth curves with respect to the distribution density of the volumes of the Voronoi cells. Agreement with the experiments is excellent.

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Li, Bin, Xinjun Jing, and Junsheng Yuan. "Phase Equilibrium of the Quaternary System LiBr-Li2SO4-KBr-K2SO4-H2O at 308.15 K." Processes 10, no. 5 (April 21, 2022): 823. http://dx.doi.org/10.3390/pr10050823.

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The phase equilibria of the reciprocal quaternary system LiBr-Li2SO4-KBr-K2SO4-H2O and its ternary sub-systems LiBr-Li2SO4-H2O and KBr-K2SO4-H2O at 308.15 K were studied using the isothermal dissolution equilibrium method. Then, the solubility data of the equilibrium solutions were collected, and the phase diagrams were plotted. The phase diagrams of the ternary sub-systems at 308.15 K were compared with those at other temperatures. This study found that the phase diagram of the LiBr-Li2SO4-H2O system at 308.15 K consisted of an invariant point, two solid-phase crystallization regions of Li2SO4·H2O and LiBr·2H2O, and their corresponding solubility curves. The system generated two hydrated salts, which belonged to the hydrate type I phase diagram. The phase diagram of the KBr-K2SO4-H2O system at 308.15 K consisted of an invariant point, two univariant solubility curves, and two solid-phase crystallization regions of KBr and K2SO4, and no solid solution and double salts were formed. Thus, it belonged to a simple co-saturation type phase diagram. In the LiBr-Li2SO4-KBr-K2SO4-H2O system, K2SO4·Li2SO4 double salt formed at 308.15 K, and the phase diagram consisted of three invariant points, five crystallization regions, and seven univariant solubility curves.

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Menyhárd, Alfréd, Márton Bredács, Gergely Simon, and Zsuzsanna Horváth. "Determination of Nucleus Density in Semicrystalline Polymers from Nonisothermal Crystallization Curves." Macromolecules 48, no. 8 (April 9, 2015): 2561–69. http://dx.doi.org/10.1021/acs.macromol.5b00275.

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Jion, Adam Idu, Lin-Tang Goh, and Steve K. W. Oh. "Crystallization of IgG1 by mapping its liquid–liquid phase separation curves." Biotechnology and Bioengineering 95, no. 5 (2006): 911–18. http://dx.doi.org/10.1002/bit.21054.

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Raimo, Maria. "Kinetics of Phase Transformation of Indium in the Presence of Polytetrafluoroethylene: Implications for DSC Measurements on Polymers and Their Composites." International Journal of Polymer Science 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/690718.

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The present work focuses on the influence, at nominal constant temperatures, of an inert polymer on the crystallization kinetics of a highly conductive metal as indium (In) to show not only that the presence of a polymer allows obtaining information on the In crystallization directly from differential scanning calorimeter (DSC) curves, but also that appropriate corrections of thermal measurements on low conductivity samples are needed.

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Raduta, Aurel, Mircea Nicoară, and Cosmin Locovei. "About Thermostability of Fe-Ni-P Amorphous Alloys." Solid State Phenomena 188 (May 2012): 21–26. http://dx.doi.org/10.4028/www.scientific.net/ssp.188.21.

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A research program has been completed in order to analyze structural changes during heating of amorphous alloys belonging to Fe-Ni-P system. Special attention has been given to thermodynamics and mechanism of crystallization, to determine some aspects of development for crystalline phases. Experimental material used to determine characteristics of crystallization consisted in long ribbons, 30 thick and 18 mm wide, fabricated by mean of “Planar Flow casting” as amorphous Fe42Ni38P16B4alloy. Differential Thermal Analysis (DTA) and X-rays diffraction have been used to determine crystallization temperature of this alloy. Curves of differential thermal analysis for heating rates ranging between 1°C/minute and 20 °C/minute have been used to determine activation energy of crystallization.

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Krupiński, M., K. Labisz, and E. Jonda. "Effect of Mg addition on the crystallization kinetics of Zn-Al-Cu alloys." Journal of Mining and Metallurgy, Section B: Metallurgy, no. 00 (2020): 29. http://dx.doi.org/10.2298/jmmb200120029k.

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In this work, the main aim was to determine the effect of Mg addition on the crystallization kinetics and microstructure of Zn-10Al-1Cu alloy. The effectiveness of magnesium addition was detected on the basis of microstructure morphology investigations and changes occurring in the cooling curves of the investigated alloys. To describe the phenomena that occur in the material during solidification under various conditions caused by a change in the chemical composition as a result of the appliance of modifiers, it was decided to use methods of thermal derivative analysis, allowing to effectively and accurately describe the crystallization kinetics of the tested materials. The scientific goal of the presented work was examination of the impact of magnesium addition, affecting the crystallization kinetics of the examined alloys. Determining the relationship between the changes in the derivative curve and the related microstructure the influence of modifiers addition was analysed. The addition of Mg has caused a shift of the solidification temperature values of phases and eutectics and monotectoid transformation (????) to lower temperature values, as well as has changed the morphology of the occurring eutectic ??+?.

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ŚLAWSKA-WANIEWSKA, A., M. GUTOWSKI, H. K. LACHOWICZ, T. KULIK, and H. MATYJA. "EXPERIMENTAL EVIDENCE FOR SUPERPARAMAGNETISM IN NANOCRYSTALLINE Fe-BASED METALLIC GLASS." International Journal of Modern Physics B 07, no. 01n03 (January 1993): 942–45. http://dx.doi.org/10.1142/s0217979293002031.

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Annealing of the initially amorphous Fe66Cr8Cu1Nb3Si9B13 metallic glass above its crystallization temperature leads to the ultrafine crystalline structure of the bcc-FeSi solid solution with a relatively wide distribution of the particle sizes 9≤D≤35 nm. At elevated temperatures the magnetization curves no longer show hysteresis and ideal superparamagnetic behavior is observed. The kinetics of magnetic moment increase during the crystallization process at the time of annealing is also presented.

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Bourguiba, Néji, and Tahar Jouini. "Lignes monovariantes de l'isotherme 75 °C du système quaternaire réciproque: H3PO4–K2SO4–H2SO4–K3PO4–H2O." Canadian Journal of Chemistry 71, no. 11 (November 1, 1993): 1816–20. http://dx.doi.org/10.1139/v93-226.

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The boundary curves and quaternary invariant points of the reciprocal system H3PO4–K2SO4–H2SO4–K3PO4–H2O were investigated at 75 °C and 1 atm by chemical analysis of solutions in equilibria, respectively, with two or three salts. Eleven compounds occur in this system. Only eight of them have crystallization areas inside Janecke's prism; these are K2SO4, K2SO4•KHSO4, K2SO4•7KHSO4•H2O, KHSO4, KH2PO4•KHSO4, KH5(PO4)2, KH2PO4, and a solid solution K8(H2PO4)1+x(HSO4)7−x, 0 ≤ x ≤ 1, of substitution type continuous between the two limiting compositions KH2PO4•7KHSO4 and KH2PO4•3KHSO4. The crystallization fields of 3K2HPO4•KH2PO4•2H2O, K2HPO4, and K3PO4•3H2O are very close to the solubility curves of the ternary system K3PO4–H3PO4–H2O. Results are explained and discussed.

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Fukami, Takeshi, I. Noda, M. Asada, D. Okai, and T. Yamasaki. "Crystal Growth in Amorphous Binary Alloys of Zr-Ni System." Advanced Materials Research 26-28 (October 2007): 675–78. http://dx.doi.org/10.4028/www.scientific.net/amr.26-28.675.

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A crystallization process in an amorphous state under isothermal condition is examined for binary alloys ZrNi and ZrNi2 by differential thermal analysis (DTA). Time dependence of DTA curves is measured at several constant temperatures just below crystallization temperature. The fraction of crystallized volume in amorphous state and its time evolution during isothermal annealing are measured. These data are analyzed by the Johnson-Mehl–Avrami formula. The Avrami exponent is 2.4±0.1 for ZrNi and 3~4 depending on the set temperature for ZrNi2. The activation energy for crystallization of amorphous ZrNi and ZrNi2 was estimated by plots of lnt1/2 vs. 1/T.

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Wang, Xiao Jun, Tian Dong Xia, and Xue Ding Chen. "Kinetics Study on Non-Isothermal Crystallization of Amorphous Alloy Mg₆₅Cu₁₅Ag₁₀Y₁₀." Advanced Materials Research 413 (December 2011): 432–38. http://dx.doi.org/10.4028/www.scientific.net/amr.413.432.

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The crystallization kinetics of amorphous alloy Mg65Cu15Ag10Y10has been studied by differential scanning calorimetry in the mode of continuous heating annealing. It is found that both DSC curves and activation energy show a strong dependence on the heating rate. The activation energy for crystallization are determined as 186.1 and 184.4 KJ mol−1for the heating rates β=5-20 Kmin−1, and 107.5 and 110.0 KJmol−1for the heating rates β=20-80Kmin−1, when using the Kissinger equation and the Ozawa equation, respectively. Local activation energy at any volume fraction crystallized was obtained by the general Ozawa's isoconversional method. The average value of local activation energy for heating rates ranging from 5 to 20Kmin−1is 180.9 KJ mol−1and for heating rates ranging between 20 and 80Kmin−1is 110.2 KJ mol−1. Using the Suriñach curve fitting procedure, the kinetics mode was specified. The JMA kinetics is manifested as a rule in the early stages of the crystallization. The JMA exponent,n, initially being larger than 4 and continuously decreases to about 2 along with the development of crystallization. The NGG-like mode dominates in the advanced stages of the transformation. These two modes are mutually independent. The proportion between the JMA-like and the NGG-like modes is related to the heating rate.

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Wang, Yan Hang, Kun He, Cheng Kui Zu, and Jiang Chen. "Study on Crystallization Kinetics of Li₂O-Al₂O₃-TiO₂-P₂O₅ Glass by Non-Isothermal Technique." Advanced Materials Research 535-537 (June 2012): 1629–33. http://dx.doi.org/10.4028/www.scientific.net/amr.535-537.1629.

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The crystallization kinetics of Li2O-Al2O3-TiO2-P2O5 (LATP) glass was studied by differential scanning calorimeter (DSC) and X-ray diffraction (XRD) techniques. The results showed that DSC curves of LATP glass have a single glass transition temperature followed by one crystallization peak for β = 5 K/min and two crystallization temperatures Tp1 and Tp2 for β ≥ 10 K/min. The activation energies of crystallization obtained from Kissinger model of the first exothermal peak and the second exothermal peak of LATP glass are 251 kJ/mol and 310 kJ/mol, respectively. The Avrami exponents of the both crystallization peaks are approximately 3, indicating that the three-dimensional crystalline growth during its amorphous to crystalline transformation. LiTi2(PO4)3 and unknown crystalline phases firstly form when the mother glass was annealed at 973 K. With increasing of annealing temperature, AlPO4 phase appears.

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35

Sláma, Ivo, and Jarmila Malá. "Induction period of crystallization of zinc chloride solutions in ethylene glycol." Collection of Czechoslovak Chemical Communications 55, no. 10 (1990): 2428–31. http://dx.doi.org/10.1135/cccc19902428.

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The dependence of the induction period of crystallization on the supercooling was examined for the ZnCl2-ethylene glycol system at mole fractions of the salt from 0 to 0.07, and treated in terms of the TTT (Time-Temperature-Transformation) diagram. The critical induction period of crystallization increases substantially on the addition of ZnCl2 to ethylene glycol. The thermal stability of supercooled liquids is discussed in terms of the shape and position of the TTT curves.

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36

Clavaguera-Mora, M. T., M. D. Baró, S. Suriñach, and N. Clavaguera. "Crystallization behavior of some melt spun Nd–Fe–B alloys." Journal of Materials Research 5, no. 6 (June 1990): 1201–6. http://dx.doi.org/10.1557/jmr.1990.1201.

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The kinetics of crystallization of four amorphous (or partially amorphous) melt spun Nd–Fe–B alloys induced by thermal treatment is studied by means of differential scanning calorimetry and scanning electron microscopy, In the range of temperatures explored experimentally, the crystallization process is thermally activated and generally proceeds in various stages. The Curie temperature and the crystallization behavior have been measured. The apparent activation energy of crystallization of most of the crystallization stages has been determined for each melt spun alloy. The explicit form of the kinetic equation that best describes the first stage of crystallization has been found. It follows in general the Johnson-Mehl-Avrami-Erofe'ev model, but clear deviations to that model occur for one alloy. Scanning electron microscopy demonstrates that preferentially hetereogeneous nucleation occurs at the ribbon surface which was in contact with the wheel. From crystallization kinetics results the lower part of the experimental time-temperature-transformation curves for all studied alloys are deduced and extrapolated to the high temperature limit of their range of validity, also deduced.

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37

Giudici, Paolo, Antonietta Baiano, Paola Chiari, Luciana De Vero, Babak Ghanbarzadeh, and Pasquale Massimiliano Falcone. "A Mathematical Modeling of Freezing Process in the Batch Production of Ice Cream." Foods 10, no. 2 (February 4, 2021): 334. http://dx.doi.org/10.3390/foods10020334.

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This study deals with the mathematical modeling of crystallization kinetics occurring during batch production of the ice cream. The temperature decrease was recorded in-situ through a computerized wireless system. A robust pattern-recognition algorithm of the experimental cooling curves was developed to determine the initial freezing point. The theoretical freezing point was used to calibrate the whole time-temperature profile. Finally, a modified Gompertz’s function was used to describe the main steps of crystallization kinetics. Derivative analysis of the Gompertz’s function allowed to determine the time-temperature physical markers of dynamic nucleation, ice crystal growth and air whipping. Composition and freezing properties were used as input variables in multivariate analysis to classification purposes of the ice cream mixtures as a function of their ability to produce high-quality ice cream. The numerical analysis of the whole cooling curve was used to build predictive models of the ice cream quality indices.

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Qu, Dezhi, Jiayang Cai, Fei Huang, Jinyu Zhang, Huajiang Zuo, Shuai Sun, Jinghua Liu, and Yongping Bai. "High-Performance Optical PET Analysis via Non-Isothermal Crystallization Kinetics." Polymers 14, no. 15 (July 27, 2022): 3044. http://dx.doi.org/10.3390/polym14153044.

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The optical properties of PET have always been a problem that related research has been trying to break through. In the previous work, we modified PET by adding PSLDH (phosphate antioxidant) to obtain a PET film with excellent optical properties. Through non-isothermal crystallization kinetic analysis of modified PET, we hope to verify the conclusion of optical properties by the effect of PSLDH addition on the crystallization properties of PET. PET and PSLDH modified PET were tested by DSC at different cooling rates. The non-isothermal crystallization kinetic process was calculated and analyzed by Jeziorny and Mo methods and the non-isothermal crystallization activation energy was analyzed by Kissinger and Friedman methods by analyzing the DSC curves. The results show that the addition of PSLDH at 0.05 wt% can make the crystallization of PET smaller and slower, which is the same as the case required for excellent optical properties. At the same time, the results can also guide the processing of the optical PET film.

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Duarte, D. M., R. Richert, and K. Adrjanowicz. "Bimodal crystallization rate curves of a molecular liquid with Field-Induced polymorphism." Journal of Molecular Liquids 342 (November 2021): 117419. http://dx.doi.org/10.1016/j.molliq.2021.117419.

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Mahdaoui, M., T. Kousksou, J. M. Marín, T. El Rhafiki, and Y. Zeraouli. "Numerical simulation for predicting DSC crystallization curves of tetradecane–hexadecane paraffin mixtures." Thermochimica Acta 591 (September 2014): 101–10. http://dx.doi.org/10.1016/j.tca.2014.07.021.

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41

Huettmann, Hauke, Susanne Zich, Matthias Berkemeyer, Wolfgang Buchinger, and Alois Jungbauer. "Design of industrial crystallization of interferon gamma: Phase diagrams and solubility curves." Chemical Engineering Science 126 (April 2015): 341–48. http://dx.doi.org/10.1016/j.ces.2014.12.018.

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Sláma, Ivo, and Jarmila Malá. "The supercooling ability of calcium nitrate solutions in ethylene glycol." Collection of Czechoslovak Chemical Communications 54, no. 10 (1989): 2711–14. http://dx.doi.org/10.1135/cccc19892711.

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The dependence of the induction period of crystallization on the supercooling was determined for the Ca(NO3)2-ethylene glycol system at mole fractions of the former from 0 to 0.049, and treated in terms of the TTT (Time-Temperature-Transformation) diagram. Addition of Ca(NO3)2 to ethylene glycol brings about a substantial increase in the critical induction period of crystallization. The thermal stability of glasses is discussed in terms of the shape and position of the TTT curves.

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43

Zhu, Yu Ying, Qiang Li, Yun Hua He, Ge Wang, and Xing Hua Wang. "Crystallization Kinetics of Ti₅₀Fe₂₂Ni₂₂Sn₆ Amorphous Powders." Applied Mechanics and Materials 108 (October 2011): 12–17. http://dx.doi.org/10.4028/www.scientific.net/amm.108.12.

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The Ti50Fe22Ni22Sn6 amorphous powder was prepared by mechanical alloying with a high-energy planetary ball mill. Crystallization kinetics of the milled amorphous powders was investigated by DSC. Thermal analysis showed that when the heating rate increasing from 10K/min to 40K/min, the super-cooled liquid region of milled amorphous alloy increased from 93K to 110K. On the basis of the obtained DSC curves, the characteristic temperatures of the amorphous powders could be measured. The equations of Kissinger and Ozawa were used to calculate the crystallization activation energies of the milled amorphous alloy for comparing. The activation energy for the glass transition Eg had the maximum values of 650KJ/mol and 629KJ/mol calculated from Kissinger and Ozawa, respectively. In addition, the second crystallization process had a higher activation energy value comparing with the others crystallization events.

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44

Meng, Zong, Lijun Yang, Wenxin Geng, Yubo Yao, Xingguo Wang, and Yuanfa Liu. "Kinetic Study on the Isothermal and Nonisothermal Crystallization of Monoglyceride Organogels." Scientific World Journal 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/149753.

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The isothermal and nonisothermal crystallization kinetics of monoglyceride (MAG) organogels were studied by pulsed nuclear magnetic resonance (pNMR) and differential scanning calorimetry (DSC), respectively. The Avrami equation was used to describe the isothermal crystallization kinetics and experimental data fitted the equation fairly well. Results showed that the crystal growth of MAG organogels was a rod-like growth of instantaneous nuclei at higher degrees of supercooling and a plate-like form with high nucleation rate at lower degrees of supercooling. The exothermic peak in nonisothermal DSC curves for the MAG organogels became wider and shifted to lower temperature when the cooling rate increased, and nonisothermal crystallization was analyzed by Mo equation. Results indicated that at the same crystallization time, to get a higher degree of relative crystallinity, a higher cooling rate was necessary. The activation energy of nonisothermal crystallization was calculated as 739.59 kJ/mol according to the Kissinger method. Therefore, as the results of the isothermal and nonisothermal crystallization kinetics for the MAG organogels obtained, the crystallization rate, crystal nucleation, and growth during the crystallization process could be preliminarily monitored through temperature and cooling rate regulation, which laid the foundation for the real industrial manufacture and application of the MAG organogels.

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45

KAVATHEKAR, PARITOSH A., BRUCE A. CRAIG, ALAN M. FRIEDMAN, CHRIS BAILEY-KELLOGG, and DEVIN J. BALKCOM. "CHARACTERIZING THE SPACE OF INTERATOMIC DISTANCE DISTRIBUTION FUNCTIONS CONSISTENT WITH SOLUTION SCATTERING DATA." Journal of Bioinformatics and Computational Biology 08, no. 02 (April 2010): 315–35. http://dx.doi.org/10.1142/s0219720010004781.

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Scattering of neutrons and X-rays from molecules in solution offers alternative approaches to the study of a wide range of macromolecular structures in their solution state without crystallization. We study one part of the problem of elucidating three-dimensional structure from solution scattering data, determining the distribution of interatomic distances, P(r), where r is the distance between two atoms in the protein molecule. This problem is known to be ill-conditioned: for a single observed diffraction pattern, there may be many consistent distance distribution functions, and there is a risk of overfitting the observed scattering data. We propose a new approach to avoiding this problem: accepting the validity of multiple alternative P(r) curves rather than seeking a single "best." We place linear constraints to ensure that a computed P(r) is consistent with the experimental data. The constraints enforce smoothness in the P(r) curve, ensure that the P(r) curve is a probability distribution, and allow for experimental error. We use these constraints to precisely describe the space of all consistent P(r) curves as a polytope of histogram values or Fourier coefficients. We develop a linear programming approach to sampling the space of consistent, realistic P(r) curves. On both experimental and simulated scattering data, our approach efficiently generates ensembles of such curves that display substantial diversity.

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Love, John A., Shu-Hua Chou, Ye Huang, Guilllermo C. Bazan, and Thuc-Quyen Nguyen. "Effects of solvent additive on “s-shaped” curves in solution-processed small molecule solar cells." Beilstein Journal of Organic Chemistry 12 (November 28, 2016): 2543–55. http://dx.doi.org/10.3762/bjoc.12.249.

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A novel molecular chromophore, p-SIDT(FBTThCA8)2, is introduced as an electron-donor material for bulk heterojunction (BHJ) solar cells with broad absorption and near ideal energy levels for the use in combination with common acceptor materials. It is found that films cast from chlorobenzene yield devices with strongly s-shaped current–voltage curves, drastically limiting performance. We find that addition of the common solvent additive diiodooctane, in addition to facilitating crystallization, leads to improved vertical phase separation. This yields much better performing devices, with improved curve shape, demonstrating the importance of morphology control in BHJ devices and improving the understanding of the role of solvent additives.

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Hussain, Syeda A., and Michelle S. Hoo Fatt. "The Behavior of Carbon Black-Filled Natural Rubber under High Strain Rates3." Tire Science and Technology 34, no. 2 (June 1, 2006): 119–34. http://dx.doi.org/10.2346/1.2218377.

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Abstract Tensile tests were conducted to obtain the deformation and failure characteristics of unfilled natural rubber (NR) and natural rubber with 25, 50, and 75 phr of N550 carbon black filler under quasistatic and dynamic loading conditions. The quasistatic tests were performed on an electromechanical INSTRON machine, while the dynamic test data were obtained from tensile impact experiments using a Charpy impact apparatus. In general, the modulus of the stress-extension ratio curves increases with increasing strain rate up to about 407, 367, 346, and 360 s−1 for unfilled, and 25, 50, and 75 phr for filled NR, respectively. Above these strain rates, the unfilled and filled natural rubber stress-extension ratio curves remained unchanged. The modulus increased with increasing strain rate because there was little time for stress relaxation. Above a critical strain rate, no change in modulus was observed because the time of the experiment was short compared to the lowest characteristic relaxation time of the material. Dynamic stress-extension ratio curves did not have the very sharp upturn at break, which is observed from strain-induced crystallization in natural rubber under quasistatic loading. Strain-induced crystallization appeared to be suppressed at high rates of loading. In fact, the highest dynamic tensile strength for the 25- and 50-phr carbon black-filled natural rubbers was smaller than those under quasistatic loading, while the highest dynamic tensile strength of the 75-phr carbon black-filled NR was greater than that in the static test. This indicated that high amounts of carbon black fillers will impede strain-induced crystallization in natural rubber.

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Hakeem, A. M. Abdel, M. M. Abd El-Raheem, M. M. Wakkad, H. F. Mohamed, H. M. Ali, SK Mohamed, and A. K. Diab. "Modeling of thermal studies on melt quenched Ge₁₈Bi₄Se₇₈ chalcogenide." Physica Scripta 96, no. 12 (December 1, 2021): 125727. http://dx.doi.org/10.1088/1402-4896/ac3c5d.

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Abstract The crystallization characteristics for Ge18Bi4Se78 glass are studied in this work by means of differential thermal analysis (DTA) under non-isothermal conditions. One stage endothermic glass transition and one exothermic crystallization are observed in the DTA curves. The results of topological constraints for Ge18Bi4Se78 glass show that the calculated value of glass transition temperature (Tg) is very close to that of the experimental results. The as-prepared, as well as the annealed samples, are examined using x-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDX), scan electron microscope (SEM) techniques. Avrami’s exponent (n) found to have an average value of 1.61 ± 0.2 reveals a mixture of one dimensional and surface nucleation stages of growth. Many models are used to estimate the activation energies for glass transition (Eg) and crystallization (Ec). The crystallization process was found to be described by the Sestak- Berggren SB(M, N) model.

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Révész, Á., L. K. Varga, S. Suriñach, and M. D. Baró. "Thermal stability, crystallization kinetics, and grain growth in an amorphous Al85Ce5Ni8Co2 alloy." Journal of Materials Research 17, no. 8 (August 2002): 2140–46. http://dx.doi.org/10.1557/jmr.2002.0315.

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Thermal stability and crystallization kinetics of the melt-quenched amorphous Al85Ce5Ni8Co2 alloy were investigated by x-ray diffraction and differential scanning calorimetry (DSC). The glass transition was followed by a supercooled liquid region (21 °C) and then by a two-step crystallization process. The final microstructure contained Al3Ce, α–Al, Al3Ni, and Al9Co2 phases. Isothermal annealing of the as-quenched samples in the range of 275–285 °C showed that both crystallization reactions occurred through a nucleation and growth process. Continuous heating DSC measurements following pre-anneals for different times were also carried out to study the crystallization kinetics and the stability of the material. The Avrami analysis of the isothermal DSC-curves revealed that the 3-dimensional nucleation and growth process became more dominant with increasing annealing temperature. The average specific grain boundary energy corresponded to high-angle grain boundaries and indicated independent nucleation events.

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50

Błoch, K., M. Nabiałek, M. Dośpiał, and S. Garus. "Crystallization of Fe-Based Bulk Amorphous Alloys." Archives of Metallurgy and Materials 60, no. 1 (April 1, 2015): 7–10. http://dx.doi.org/10.1515/amm-2015-0001.

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Abstract The aim of this paper is to present the results of crystallization studies for the bulk amorphous (Fe0.61Co0.10Zr0.025Hf0.025 Ti0.02W0.02B0.20)98Y2, Fe61Co10TixY6B20, Fe61Co10Ti2Y7B20 alloys. The crystallization of the alloys was studied by differential scanning calorimetry (DSC). The amorphicity of the investigated alloys in the as-quenched state was testified using Mossbauer spectroscopy, X-ray diffractometry and transmission electron microscopy. Moreover, X-ray diffractometry was applied to structure investigations of partially crystallized samples. The crystallization process in the investigated alloys occurs in one or two stages. Two peaks in the DSC curves can be overlapped or well separated indicating the complex crystallization processes. From X-ray diffraction we have stated that in both types of devitrification the crystalline phase can be ascribed to the α-FeCo. In the first stage the crystalline grains seem to grow from the nuclei frozen in the samples during the rapid quenching, whereas in the second one both the growth of the existed grains and creation of new ones during annealing may occur.

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Journal articles on the topic 'Crystallization curves'

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