Graduate Institute ofFerrous Technology



[CTL] Prof. Jung-Wook Cho: Thermal history driven molecular structure transitions in alumino-borosilicate glass
GIFT 18-09-30 23:19


The glass network structure governs various thermos-physical properties such as viscosity, thermal, and electrical conductivities, and crystallization kinetics. We investigated the effect of temperature on structural changes in a Na2O-CaOAl2O3-SiO2-B2O3 glass system using 27Al MAS NMR spectroscopy. Around the glass transition temperature, most of aluminate structures exist as AlO4, acting as a glass former. When the temperature is above the melt crystallization temperature, the AlO4 structure is drastically decreased and glass structures are mainly composed of AlO5 and AlO6, acting as glass modifiers. Thermodynamic assessment based on Gibbs energy minimization was used to confirm the dependency
of aluminate structure’s amphoteric characteristic on temperature by calculating the site fraction of aluminate molecular structures at different temperatures. Temperature-induced aluminate structural variation can also influence silicate and
borate structural changes, which have been confirmed by the 29Si and 11B NMR spectra. 

glass network, molecular structure, solid-state MAS NMR, structural variations, temperature effect

glass structure and crystallization.pdf 164회 (511.6K) 2018-10-01 00:19:19

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[CTL] Prof. Jung-Wook Cho: oxide metallurgy during AM

 In laser metal deposition (LMD) process, meltpool oxidation is inevitable due to high working temperature, which results in finely dispersed non-metallic inclusions in the steel matrix. In this paper, cha…

GIFT | 09-30 Time

2013 Acta Student Award winner, Dr. Jae Hoon Jang

​​​Dr. Jae Hoon Jang, former Ph.D. student in CML, wins the Acta Student Award in this year. This award is given to the person who has made a major contribution to the paper in Acta journal, which demonstrate…

GIFT | 07-31 Time

The NIMS Award 2012 to Prof. Bhadeshia

​Prof. Harry Bhadeshia, the Director of CML was awarded the 2012 NIMS award for distinguished achievements in research and development of structural materials and invaluable contributions to NIMS (National Ins…

GIFT | 06-14 Time