scholarly journals The effects of additives in to heat treatment temperature and time on the crystallinity of lithium silicate glass-ceramic

Author(s):  
S. A Zaidan ◽  
M. F Al-Hilli ◽  
D. F Mahdi
2020 ◽  
Vol 10 (14) ◽  
pp. 4940
Author(s):  
Muhammad Faris Syazwan Mohd Shofri ◽  
Mohd Hafiz Mohd Zaid ◽  
Khamirul Amin Matori ◽  
Yap Wing Fen ◽  
Yazid Yaakob ◽  
...  

A new transparent zinc silicate glass-ceramic was derived from the 55ZnO–5B2O3–40SLS glass system via a controlled heat-treatment method. The precursor glass sample was placed through the heat-treatment process at different temperatures to study the progress in phase transformation, optical performance and emission intensity of the zinc silicate glass-ceramics. For this project, material characterization was measured through several tests using densimeter and linear shrinkage measurement, X-ray diffraction (XRD), Fourier transform infrared reflection (FTIR), ultraviolet–visible (UV–Vis) and photoluminescence (PL) spectroscopy. The density and linear shrinkage measurements show that the density of the particular glass-ceramic samples increases with the progression of heating temperature. The XRD analysis displays the result in which the zinc silicate crystal starts to grow after the sample was treated at 700 °C. In addition, the FTIR spectra indicated that the crystallization of the zinc silicate phase occurred with the appearance of SiO4, ZnO4 and Si-O-Zn bands. UV–visible exhibited the small changes when the value for the optical band gap decreased from 3.867 to 3.423 eV, influenced by the temperature applied to the sample. Furthermore, the PL spectroscopy showed an enhancement of broad green emission at 534 nm upon the increased heat-treatment temperature. Thus, it can be concluded there is the progression of crystal growth as the heat-treatment temperature increased; three emission peaks appeared at 529, 570 and 682 nm for the green, yellow and red emissions, respectively.


1995 ◽  
Vol 78 (4) ◽  
pp. 1115-1117 ◽  
Author(s):  
Sylvia M. Johnson ◽  
Robert H. Lamoreau ◽  
Ronald E. Loehman

2008 ◽  
Vol 01 (01) ◽  
pp. 25-30 ◽  
Author(s):  
MEHDI MIRSANEH ◽  
BEATA ZALINSKA ◽  
OLIVER P. LEISTEN ◽  
IAN M. REANEY

A castable, low melting temperature glass-ceramic system (30% Bi 2 O 3, 30% Nb 2 O 5, 30% B 2 O 3 and 10% SiO 2, in mol%) suitable for microwave applications is fabricated and characterized. Depending on heat treatment temperature, the glass ceramic exhibits permittivity, 15 ≤ ε r ≤ 41, temperature coefficient of resonant frequency of -160 ≤ τ f ≤ +100 MK -1 and microwave quality factor of 300 GHz ≤ Qf ≤ 15000 GHz . The highest Qf occurs at 960°C heat treatment with ε r = 15, τ f = -80 MK -1 and Qf = 15000 GHz . Applications are envisaged such as castable dielectrically-loaded antenna pucks, removing the need for complex ceramic processing.


2012 ◽  
Vol 509 ◽  
pp. 303-307 ◽  
Author(s):  
Pei Jing Tian ◽  
Jin Shu Cheng ◽  
Gao Ke Zhang ◽  
Qin Yang

Eu2O3 doped boron silicate glass appearing phase separation have been prepared and characterized. The heat treatment temperature was determined by DTA, the microstructure and optical properties of the glass were studied by SEM and fluorescence spectra. The adding of Eu2O3 restrained the phase separation and crystallization of the glass. Eu ions exist in the glass samples as the Eu3+ ions, rather than the Eu2+ ions. As the heat treatment temperature increases, the phase separation region increased gradually, and the luminescent intensity increases.


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