Crystallization behavior, microstructure and dielectric properties of lead titanate glass ceramics in the presence of Bi2O3 as a nucleating agent

2010 ◽  
Vol 30 (6) ◽  
pp. 1453-1460 ◽  
Author(s):  
S. Golezardi ◽  
V.K. Marghussian ◽  
A. Beitollahi ◽  
S.M. Mirkazemi
2020 ◽  
Vol 12 (4) ◽  
pp. 510-515
Author(s):  
Byeongguk Kang ◽  
Seunggu Kang

Diopside is a ceramic material with excellent properties including a low dielectric constant, high thermal conductivity, low sintering temperature below 1000 °C, and high mechanical strength. It has been applied to wireless and optical communications, substrates for touch panels, lenses for UV-LED, building materials, and so on. In this study, glass-ceramics containing nano-sized diopside crystals were fabricated, and their transmittance at visible light and photoluminescence were evaluated. In particular, TiO2 was added as a nucleating agent to suppress the surface crystallization phenomenon and Mn was used as a dopant to emit red light. The glass-ceramics were prepared by heat treatment at a temperature lower than the maximum crystal growth temperature (TP) calculated from the non-isothermal analysis method using differential thermal analysis (DTA) for the formation of nano-sized crystals. For glass containing 20 wt% of TiO2, the Avrami constant was calculated to be 2.23 and the activation energy required for crystal growth to be 549 kJ/mol, reflecting typical bulk crystallization behavior. Glass-ceramics with high light transmittance up to 70% were obtained by inducing the bulk crystallization behavior, and the diopside crystal size was less than 10 nm, which was equal to or higher than that of commercialized transparent glass-ceramic products. Glass-ceramic specimens doped with Mn showed luminescence of 736∼766 nm wavelength at excitation light of 365 nm wavelength. The emission peak intensity increased with the amount of dopant added, but gradually decreased with increasing crystallinity of the diopside phase.


2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Yici Wang ◽  
Qi Jiang ◽  
Guoping Luo ◽  
Wenwu Yu ◽  
Yan Ban

In the process of glass-ceramics prepared with Baotou steel blast furnace slag, quartz sand, and other raw materials by melting method, the mutual influence of the special components such as CaF2, REXOY, TiO2, K2O, and Na2O in the blast furnace slag on the crystallization behavior of parent glass was investigated using differential thermal analysis (DTA) and X-ray diffraction (XRD). The results show that the special components in slag can reduce the crystallization temperature and promote crystallization of glass phase, which belongs to surface crystallization of glass, and they cannot play the role of the nucleating agent; the major crystal phase composed of diopside, diopside containing aluminum and anorthite, is slightly different from the expected main crystal phase of diopside. Therefore, the nucleating agents of proper species and quantity must be added into the raw materials in order to obtain glass-ceramics. The results have important theoretical guidance meaning for realizing industrial production of Baotou steel blast furnace slag glass-ceramics preparation.


2010 ◽  
Vol 502 (2) ◽  
pp. 387-391 ◽  
Author(s):  
Hsing-I Hsiang ◽  
Li-Then Mei ◽  
Chi-Shiung Hsi ◽  
Wen-Chang Liao ◽  
Fu-Su Yen

2016 ◽  
Vol 697 ◽  
pp. 253-256 ◽  
Author(s):  
Jin Zhuang Liu ◽  
Zhong Hua Yao ◽  
Nuo Xin Xu ◽  
Qi Long Zhang ◽  
Hui Yang

CaO–B2O3–SiO2 (CBS) glass-ceramics containing ZrO2 were prepared by conventional melting and heat treated crystallization method. The effects of ZrO2 on the crystallization behavior, sintering characterization and dielectric properties of the glass-ceramics were analyzed respectively. The results indicated that ZrO2 addition can improve the crystallization and densification of CBS glass-ceramics. The major crystallized phase of sample with≥7wt% ZrO2 was cyclowollastonite (α-CaSiO3).It is found that the optimal sintering condition for the glass-ceramics is 770 oC for 30min. CBS glass ceramics sample with 7wt% ZrO2 shows the best sintering characterization and dielectric properties (ρ= 2.71g/cm3, εr ≈8.8,tan δ=2.36×10-3 at 1 MHz), which is supposed to be suitable for LTCC application.


2014 ◽  
Vol 459 (1) ◽  
pp. 172-187 ◽  
Author(s):  
Anuson Niyompan ◽  
Kanita Srisurat ◽  
Rungnapa Tipakontitikul

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