AI Chat Paper
Note: Please note that the following content is generated by AMiner AI. SciOpen does not take any responsibility related to this content.
{{lang === 'zh_CN' ? '文章概述' : 'Summary'}}
{{lang === 'en_US' ? '中' : 'Eng'}}
Chat more with AI
PDF (2.4 MB)
Collect
Submit Manuscript AI Chat Paper
Show Outline
Outline
Show full outline
Hide outline
Outline
Show full outline
Hide outline
Research Article | Open Access

Mullite whiskers prepared by molten salt method using Si powders

Wei WANGa,*( )Hongwei LIbYajie GUObQiang SUNaChen CHENa
Department of Chemical Engineering, College of Environment Science and Engineering, Chang'an University, Xi'an 710054, China
College of Materials Science and Engineering, Chang'an University, Xi'an 710061, China
Show Author Information

Abstract

Mullite whiskers were prepared from Si powders in molten Al2(SO4)3-Na2SO4 mixture salts with different Al/Si molar ratio (R) of raw materials. The resulting mullite whiskers, had been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and infrared spectroscopy analysis (FT-IR). Mullite phase was obtained in molten salts when the temperature reached at 850 ℃. SEM and EDS results revealed that two kinds of microstructures were formed in the final product, Al-rich mullite pellets and clusters of tiny mullite crystals, and the content of Al-rich mullite pellets increased with the higher Al/Si molar ratio (R) adopted in raw materials. A new oxidation-dissolution mechanism was proposed to explain mullite whiskers growth. According to thermodynamic analysis, mullite phase might be spontaneously formed as the temperature reached the decomposition temperature of aluminum sulfate (1023 K).

References

[1]
Zhang YB, Ding YP, Gao JQ, et al. Mullite fibres prepared by sol-gel method using polyvinyl butyral. J Eur Ceram Soc 2009, 29:1101-1107.
[2]
Bagchi B, Das S, Bhattacharya A, et al. Nanocrystalline mullite synthesis at a low temperature: Effect of copper ions. J Am Ceram Soc 2009, 92:748-751.
[3]
Kong LB, Zhang TS, Ma J, et al. Mullitization behavior and microstructural development of B2O3-Al2O3-SiO2 mixtures activated by high-energy ball milling. Solid Sate Sci 2009, 11:1333-1342.
[4]
Zhang TS, Kong LB, Du ZH, et al. In situ interlocking structure in gel-derived mullite matrix induced by mechanoactivated commercial mullite powders. Scripta Mater 2010, 63:1132-1135.
[5]
Zhang TS, Kong LB, Du ZH, et al. Tailoring the microstructure of mechanoactivated Al2O3 and SiO2 mixtures with TiO2 addition. J Alloys Compd 2010, 506:777-783.
[6]
Roy B, Fuierer PA. Molten salt synthesis of Bi-4(V0.85Co0.15)(2)O11-delta (BICOVOX) ceramic powders. J Am Ceram Soc 2009, 92:520-523.
[7]
Li JF, Lin H, Li JB, et al. Effects of different potassium salts on the formation of mullite as the only crystal phase in kaolinite. J Eur Ceram Soc 2009, 29:2929-2936.
[8]
Park YM, Yang TY, Yoon SY, et al. Mullite whiskers derived from coal fly ash. Mater Sci Eng A 2007, 454-455:518-522.
[9]
Zhang PY, Liu JC, Du HY, et al. Molten salt synthesis of mullite whiskers from various alumina precursors. J Alloys Compd 2010, 491:447-451.
[10]
Ouatib RE, Guillemet S, Durand B, et al. Reactivity of aluminum sulfate and silica in molten alkali-metal sulfates in order to prepare mullite. J Eur Ceram Soc 2005, 25:73-80.
[11]
Kong LB, Gan YB, Ma J, et al. Mullite phase fromation and reaction sequences with the presence of pentoxides. J Alloys Compd 2003, 351:264-272.
[12]
Kim BM, Cho YK, Yoon SY, et al. Mullite whiskers derived from kaokin. Ceram Int 2009, 35:579-583.
[13]
Zhang PY, Liu JC, Du HY, et al. Influence of silica sources on morphology of mullite whiskers in Na2SO4 flux. J Alloys Compd 2009, 484:580-584.
[14]
Levin EM, Mcmurdie HF. Phase diagrams for ceramists 1975 supplement. Am Ceram Soc OH, Westerville, 1975:1318-1318.
[15]
Liu K, Feng Q, Yang YX, et al. Preparation and characterization of amorphous silica nanowires from natural chrysotile. J Non-Cryst Solids 2007, 353:1534-1539.
[16]
Lavat AE, Grasselli MC, Tasca JE. Phase changes of ceramic whiteware slip-casting bodies studied by XRD and FTIR. Ceram Int 2007, 33:1111-1117.
[17]
Barin I. Thermochemical Data of Pure Substances. Weinheim:VCH Verlagsgesellschaft, 1989.
Journal of Advanced Ceramics
Pages 283-289
Cite this article:
WANG W, LI H, GUO Y, et al. Mullite whiskers prepared by molten salt method using Si powders. Journal of Advanced Ceramics, 2012, 1(4): 283-289. https://doi.org/10.1007/s40145-012-0028-7

780

Views

22

Downloads

22

Crossref

N/A

Web of Science

27

Scopus

0

CSCD

Altmetrics

Received: 14 September 2012
Revised: 04 November 2012
Accepted: 12 November 2012
Published: 09 January 2013
© The author(s) 2012
Return