Nucleation and Crystallization of Phosphate Glass for a PDP Barrier Rib by Differential Thermal Analysis

( Young Seok Kim ),( Kyu Ho Lee ),( Tae Ho Kim ),( Young Joon Jung ),( Bong Ki Ryu ) 대한금속재료학회 ( 구 대한금속학회 ) 2008 ELECTRONIC MATERIALS LETTERS Vol.4 No.1

Non-isothermal measurements with differential thermal analysis were used to study the nucleation and crystallization kinetics of P2O5-B2O3-ZnO-BaO-Al2O3-TiO2 crystals in bulk glass, particularly with respect to the crystallization that occurs when the glass is heated. The temperature of the nucleation rate was determined by plotting either the reciprocal of the temperature that corresponds to the maximum crystallization peak, 1/Tp, or the height of the crystallization peak, (△T)p, as a function of the nucleation temperature, Tn. The temperature at which nucleation can occur for the glass ranges from 700°C to 890°C and the temperature for the maximum nucleation is 760±5°C. The correct activation energy for the crystallization, Ec, of the glass is the same for the surface crystallization orthe bulk crystallization: namely 533 kJ/mol ± 15 kJ/mol. The analysis of the crystallization data with the Kissinger equation and the Marotta equation yields the correct value of Ec, though the crystal growth occurs only on a fixed number of nuclei. The crystallization process of a sample heat-treated at the temperature of the maximum nucleation rate was fitted to kinetic equations with an Avrami constant (n≒2) and the dimensionality of crystal growth (m≒2).

Nucleation and Crystallization of Phosphate Glass for a PDP Barrier Rib by Differential Thermal Analysis

김영석,이규호,정영준,류봉기 대한금속·재료학회 2008 ELECTRONIC MATERIALS LETTERS Vol.4 No.1

Non-isothermal measurements with differential thermal analysis were used to study the nucleation and crystallization kinetics of P2O5-B2O3-ZnO-BaO-Al2O3-TiO2 crystals in bulk glass, particularly with respect to the crystallization that occurs when the glass is heated. The temperature of the nucleation rate was determined by plotting either the reciprocal of the temperature that corresponds to the maximum crystallization peak, 1/Tp, or the height of the crystallization peak, (ΔT)p, as a function of the nucleation temperature, Tn. The temperature at which nucleation can occur for the glass ranges from 700°C to 890°C and the temperature for the maximum nucleation is 760±5°C. The correct activation energy for the crystallization, Ec, of the glass is the same for the surface crystallization orthe bulk crystallization: namely 533 kJ/mol ± 15 kJ/mol. The analysis of the crystallization data with the Kissinger equation and the Marotta equation yields the correct value of Ec, though the crystal growth occurs only on a fixed number of nuclei. The crystallization process of a sample heat-treated at the temperature of the maximum nucleation rate was fitted to kinetic equations with an Avrami constant ( ) and the dimensionality of crystal growth ( ).

Evaluation of the kinetics of unseeded batch cooling crystallization using population balance modeling: Sucrose and KNO3 case studies

김승환,Sang Yeol Lee,장지웅,양대륙 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.118 No.-

A facile method for estimating the kinetics of unseeded batch crystallization via mass and average sizemeasurements was developed. The population balance equation (PBE), reformulated as a function of bothmass and average size, was employed to determine the mass balance and obtain crystallization kinetics. An evaluation of the kinetic parameters of inorganic and organic (sucrose and KNO3) compounds wasdemonstrated through fitting the modified PBE to measured time-dependent average size and mass. The method enabled to extract of kinetic parameters of both crystal nucleation and growth. The differentcrystallization behaviours in the volume of the crystallizer and supersaturations were predicted using theevaluated kinetic parameters and validated with experiments. The developed method is useful for evaluatinglumped kinetic parameters of unseeded batch crystallizations.

Study on the Isothermal Crystallization Behaviors of PEN/TLCP Blends

( Jong Ryul Park ),( Doo Soo Yoon ),( Eung Jae Lee ),( Moon Soo Bang ),( Jae Kon Choi ) 한국고무학회 2016 엘라스토머 및 콤포지트 Vol.51 No.1

The isothermal crystallization behaviors of blends of poly(ethylene naphthalate) (PEN) and a thermotropic liquid crystalline polymer (TLCP) were investigated by differential scanning calorimetry (DSC) as functions of crystallization temperature and blend composition. Avrami analyses were applied to obtain information on the crystal growth geometry and the factors controlling the rate of crystallization. The crystallization kinetics of the PEN/TLCP blends followed the Avrami equation up to a high degree of crystallization, regardless of crystallization temperature. The calculated Avrami exponents for PEN/TLCP revealed three-dimensional growth of the crystalline region in each blend. The crystallization rate of each blend increased as the crystallization temperature decreased, and decreased as the TLCP content increased. The crystallization of PEN in the blend was affected by the addition of TLCP, which acts as a nucleating agent.

액정 고분자와 폴리(에틸렌 테레프탈레이트)블렌드의 결정화 거동

방문수(Bang Moon-Soo) 한국산학기술학회 2006 한국산학기술학회논문지 Vol.7 No.4

폴리(에틸렌 테레프탈레이트)와 액정 폴리에스테르의 블렌드를 등온 결정화 거동에 대하여 연구하였다. 블렌드내의 PET의 결정화 거동을 나타내주는 결정화 속도나 결정이 어떤 모양으로 성장하는가에 대한 정보를 얻기 위해 Avrami 식을 이용하였다. 블렌드내 PET의 결정화는 결정화온도에 무관하게 높은 결정화도에 이르기까지 Avrami 식에 잘 적용됨을 알 수 있었으며 Avrami 지수값, n이 2를 나타냄으로써 블렌드내의 PET의 결정이 I차원적으로 성장함을 알 수 있었고, 결정화 온도가 높을수록 결정화 속도가 느려짐을 조사 결과 확인하였다. The isothermal crystallization behavior of blends of poly(ethylene terephthalate) and liquid crystalline polymers(LCP) was studied. The Avrami analyses were applied to obtain the information on the crystal growth geometry and factors controlling the rate of crystallization. The crystallization kinetics for the blends followed the classical Avrami equation up to a high degree of crystallization regardless of crystallization temperature, The values of Avrami exponent, n, for PET in the blends were estimated to be around 2, which indicate that the polymer crystals grow into one-dimensional linear or fiber-like crystallization mode. The crystallization rate, as expected, decreases with increasing the crystallization temperature.

Design of isosorbide crystallization process as recovery system for poly (ethylene-co-isosorbide) terephthalate production via solubility measurements and crystallization kinetic parameter estimation

Sang Yeol Lee,Dae Ryook Yang,Ji Woong Chang 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.92 No.-

The solubility of isosorbide in ethylene glycol was measured and the crystallization kinetic parameterswere estimated via seeded batch cooling crystallization. The saturation concentration of isosorbide wasmeasured using a density meter, which enabled rapid and accurate measurement of the concentration. The crystallization kinetic parameters were estimated byfitting the population balance equation to thetime-dependent change of concentration and average crystal size. Crystallization using continuousstirred tank reactors (CSTR) was simulated with the obtained parameters, and the reliability of thesimulation was verified with experiments. The kinetic parameters estimated from seeded batchcrystallization experiments can be used for the prediction of crystallization under seeded conditions,such as CSTR. The prediction of the crystal size and concentration of the CSTR crystallizer using theestimated parameters were consistent with the experimental results. The amount and composition ofresidue obtained from industrial poly(ethylene-co-isosorbide) terephthalate process was predicted, andrecovery processes and optimum operating conditions are proposed via simulation using Aspen Plus.

Crystallization kinetics of mica glass-ceramic in the SiO2-Al2O3-MgO-K2O-B2O3-F2 System

Ediz Ercenk,Senol Yilmaz 한양대학교 세라믹연구소 2015 Journal of Ceramic Processing Research Vol.16 No.1

A mica glass-ceramic in the SiO2-Al2O3-MgO-K2O-B2O3-F2 glass system was prepared by a melting method. The crystallization behaviour and crystallization kinetics of a sample with glass-ceramic composition were examined. DTA and XRD analysis revealed the crystallization of phlogopite, fluorphlogopite, clinohumite and spinel phases. The activation energies for the precipitation of crystalline phases have been evaluated, and the crystallization mechanisms have been studied by applying DTA measurements performed at various heating rates. The results indicate that the growth of mica is a twodimensional process controlled by the crystal-glass interface reaction. The average calculated values of crystallization and viscous flow for the precipitation of crystal phases from the glass matrix were measured to be 289.9 ± 8 kJ/mol and 348.7 ± 14 kJ/mol, respectively. The mica glass-ceramics exhibited excellent performance in machinability tests without cracking or deforming.

Crystallization kinetics and magnetic properties of spinel transition metal ferrite nanoparticles

Yukun Sun,Dongyun Li,Pengzhao Gao,Zhouli Lu,Hongliang Ge 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.5

Spinel transition metal ferrite TMFe2O4 (TM = Co2+, Ni2+, Cu2+, and Zn2+) nanoparticles were prepared via a template-assistedsol-gel method followed by a calcining process, using metal nitrate precursors as raw materials. The prepared specimens werecharacterized using X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM). Their structures, magneticproperties, crystallization kinetics, and the influence of crystal size (D) on the magnetic properties were investigated. It wasfound that the crystal sizes of TMFe2O4 were positively proportional to the calcined temperature and time, and thecrystallization growth activation energy (Ea) increased with the increase of metal ionic radius. The optimum calcinationparameters were obtained to form a crystal closest to the standard crystal. Additionally, the saturation magnetization ofinverse spinel structure specimens was enhanced monotonously and their coercivity showed a potential decrease trend, whilethere was an opposite change trend for normal spinel structure specimens.

Kinetic Investigation of Thermochromic Transition, Proton Transfer Reaction, and Crystal-Crystal Phase Transformation in 1,3-bis(hydroxyethylamino)-4,6-dinitrobenzene

Han, Jae-Il,Chung, Ihn-Hee,Lee, Sang-Cheol 한국섬유공학회 2011 FIBERS AND POLYMERS Vol.12 No.7

This study investigated the main origin of the thermochromism of a novel compound, 1,3-bis(hydroxyethylamino)-4,6-dinitrobenzene (BDB). In order to unravel the relative dependence of reversible color change between yellow and orange on proton transfer reaction and crystal-crystal phase transformation, kinetic experiments were executed. The recovery rates of thermochromic transition, proton transfer reaction, and crystal-crystal phase transformation were calculated from the data measured through UV-vis spectrophotometry, IR spectrometry, and X-ray diffractometry with a lapse of time at fixed-temperatures (30, 40, and $50^{\circ}C$) after cooling from heated temperature ($150^{\circ}C$). The kinetic experiments revealed that the recovery takes place more quickly at lower temperature. At each fixed-temperature, the recovery rate is in the order of the crystal-crystal phase transformation > the proton transfer reaction > the thermochromic transition. It is concluded that the proton transfer reaction is the main origin for thermochromism of BDB in solid state and the crystal-crystal phase transformation is a collateral one.

강유전체 Fresnoite 결정을 갖는 유리의 제조 및 결정화 거동

이회관,채수진,강원호,Lee, Hoi-Kwan,Chae, Su-Jin,Kang, Won-Ho 한국마이크로전자및패키징학회 2005 마이크로전자 및 패키징학회지 Vol.12 No.2

Fresnoite($Ba_2TiSi_2O_8$)결정을 갖는 $xK_2O-(33.3-x)BaO-16.7TiO_2-50SiO_2(mole\%)$ 유리조성에서 BaO를 $K_2O$로 대체함에 따른 유리화, 열적특성 및 결정화 거풍에 관하여 관찰하였다. x(0$\le$x$\le$20)의 함량이 증가함에 따라 유리화가 용이하였으며, 유리 전이온도 및 결정화 온도가 저온부로 이동하였다. $Ba_2TiSi_2O_8$결정상의 생성을 XRD분석을 통하여 확인하였으며, x의 함량증가가 이질상의 생성과는 무관함을 보였다. 결정화 거동을 DTA를 이용한 비등온법에 의하여 조사하였으며, x의 함량증가에 따라 avrami 지수(n)가 $2.26 {\pm}0.1,\;2.03 {\pm}0.1,\;1.93{\pm}0.15$로, 활성화 에너지는 약 $279 {\pm}12kJ/mole,\;302{\pm}7kJ/ mole,\;319{\pm}1kJ/mole$ 로 변화하였으며, SEM분석결과 x의 함량 증가 시 결정의 방향성이 두드러짐이 관찰되었다. Glass formation, thermal property and crystallization behavior were investigated in $xK_2O-(33.3-x)BaO-16.7TiO_2-50SiO_2(mole\%)$ with fresnoite($Ba_2TiSi_2O_8$) crystal by replacement BaO for $K_2O$. As x(0$\le$x$\le$20) contents increased, glass formation became easy, and crystallization temperature moved on to the low temperature. Crystal phase of the $Ba_2TiSi_2O_8$ was confirmed by XRD, and the replaced x was not effected on the formation of new crystals. The kinetics of crystallization of fresnoite were studied by applying the DTA measurements carried out at different heating rates. The average avrami exponent(n) and activation energy were changed $2.26 {\pm}0.1,\;2.03 {\pm}0.1,\;1.93{\pm}0.15$, $279 {\pm}12kJ/mole,\;302{\pm}7kJ/ mole,\;319{\pm}1kJ/mole$ according to x contents, respectively. The replaced x improved the orientation of crystal growth.