Preparation of Zircon Whisker Using Carbon Black as Reducing Agent

doi:10.15541/jim20130618

Abstract

Abstract:

Zircon whisker was synthesized at 700 ℃ via non-hydrolytic Sol-Gel method using anhydrous zirconium tetrachloride (ZrCl₄) as zirconium source, tetraethylorthosilicate (TEOS) as silicon source, lithium fluoride (LiF) as mineralizer, ethanol as solvent and carbon black as reducing agent. Thermogravimetric analysis and differential thermal analysis (TG-DTA), X-ray diffraction analysis (XRD) and transmission electron microscope (TEM) were employed to characterize the influences of adding ways and amount of carbon black on the synthesis and morphology of zircon whisker. The results show that the carbon black added in form of suspension is favorable to the one-dimension growth of zircon. When 6wt% carbon black is added, optimized zircon whiskers are achieved along the growth direction of [001], which diameter and aspect ratio are in the range of 30-90 nm and 6-15, respectively. Because of carbon black reacting with oxygen to form carbon dioxide and monoxide, the adding way and amount of carbon black efficiently regulate the oxygen partial pressure in the reaction system. Reducing oxygen partial pressure can form more SiF₄gas, which is the basis of one-dimensional direction growth of zircon. However, excessively low oxygen partial pressure is against the ZrSiO₄ formation. Therefore, appropriate oxygen partial pressure can promote the growth of zircon whisker.

Key words: zircon, whisker, non-hydrolytic Sol-Gel method, carbon black

CLC Number:

TQ174

WANG San-Hai, JIANG Wei-Hui, FENG Guo, LIU Jian-Min, MIAO Li-Feng, WANG Hong-Da. Preparation of Zircon Whisker Using Carbon Black as Reducing Agent[J]. Journal of Inorganic Materials, 2014, 29(8): 835-838.

Figures/Tables 5

Fig. 1 DTA-TG curves of xerogel prepared by adding carbon black

Fig. 2 XRD patterns of the samples annealed at different temperatures

Fig. 3 TEM images of samples prepared by adding carbon black with different ways

Fig. 4 TEM photographs of samples prepared at different carbon black contents (a) 0; (b) 3wt%; (c) 6wt%; (d) 9wt%

Fig. 5 TEM (a) and HRTEM (b) images of zircon whisker Inset in Fig. 5 (a) is the corresponding SAED pattern

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