Glass structure and crystallization via two distinct thermal histories: Melt crystallization and glass crystallization

2021 ◽  
Vol 41 (1) ◽  
pp. 831-837
Author(s):  
Ji-Yeon Baek ◽  
Seung-Ho Shin ◽  
Sung-Hee Hyun ◽  
Jung-Wook Cho
2021 ◽  
Vol 29 (1) ◽  
pp. 73-76
Author(s):  
Ye. V. Skrypnik ◽  
M. P. Trubitsyn ◽  
A. O. Diachenko ◽  
M. D. Volnianskii

The glass of lithium-sodium tetragermanate LiNaGe4O9 is crystallized on heating under the control of differential scanning calorimetry and thermal gravimetric analysis. The measurements were prepared in the temperature range 300-870 K and showed the relatively weak endothermic DSC anomaly and 40-50 K above the single exothermic peak. The endothermic anomaly observed at Tg testified to softening the glass structure whereas the exothermic peak at TC manifested crystallization of the amorphous phase. Studying of TGA demonstrated smooth nearly linear dependences without any visible anomalies. Varying the heating rate from 1.2 up to 40 K/min resulted in noticeable increase of the characteristic temperatures Tg and TC. Lower limit of the glass transition temperature Tg0 was estimated with the help of the existing model. The mechanism of the LiNaGe4O9 glass crystallization is discussed.


2016 ◽  
Author(s):  
Ryan K. Stoner ◽  
◽  
Jaclyn S. Baughman ◽  
Rebecca M. Flowers ◽  
Nigel M. Kelly ◽  
...  

2019 ◽  
Author(s):  
Jordan Lubbers ◽  
◽  
Adam J.R. Kent ◽  
Frank Tepley ◽  
Dawid Szymanowski

2020 ◽  
Author(s):  
Marissa Tremblay ◽  
◽  
Darren F. Mark ◽  
John N. Carter ◽  
Simon Mason ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2626
Author(s):  
Natalia Anna Wójcik ◽  
Sharafat Ali ◽  
Jakub Lech Karczewski ◽  
Bo Jonson ◽  
Michał Bartmański ◽  
...  

Bioactive glasses have recently been extensively used to replace, regenerate, and repair hard tissues in the human body because of their ability to bond with living tissue. In this work, the effects of replacing Na2O with MgO on the electrical, biosolubility, and thermal properties of the target glass 10Na2O–60P2O5–30CaO (in mol%) were investigated. The electrical properties of the glasses were studied with the impedance spectroscopy technique. At 473 K, DC conductivity values decreased from 4.21 × 10−11 to 4.21 × 10−12 S cm−1 after complete substitution of MgO for Na2O. All samples had a similar activation energy of the DC conduction process ~1.27 eV. Conduction mechanisms were found to be due to hop of ions: Na+, Mg2+, and probable H+. FTIR analysis showed that, as the Mg content increased, the Q2 unit (PO2−) shifted towards higher wavenumbers. The proportion of Q3 unit (P2O5) decreased in the glass structure. This confirmed that the replacement of Na+ by Mg2+ was accompanied by concurrent polymerization of the calcium–phosphate glass network. The biosolubility test in the phosphate-buffered saline solution showed that the magnesium addition enhanced the biosolubility properties of Na2O–CaO–P2O5 glasses by increasing their dissolution rate and supporting forming CaP-rich layers on the surface. The glass transition temperature increased, and thermal stability decreased substantially upon substitution of Na2O by MgO.


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