Activation Energy and Synthesis of Nano-mullite by Micro-boiling Method
YANG Zhong-zheng1, YAO Ya-gang2, WONG C P2, LU Yue-jun1
1. Henan Provincial Key Material Laboratory, North China University of Water Resources and Electric Power, Zhengzhou 450011, China;
2. School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta 30332-0245, USA
Abstract：Nano-mullite was synthesized by micro-boiling method using aluminium nitrate and silica sol as raw materials, and the activation energy was studied. Grain size, phase composition and morphology of the mullite were analyzed by means of thermogravimetry-differential scanning calorimeter(TG-DSC), X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The results show that when Al/Si mole ratio is 3:1 in the raw materials, mullite starts forming at 854℃, Al-Si spinel starts transforming into mullite at 920℃, mullitization is completed at 1200℃, and activation energy of mullite synthesis is (634.52±28.90) kJ·mol-1. After mullite is calcined at 1200℃, and the mole fraction of mullite containing Al2O3 is 59.8%, the average particle size is 31.7nm, with needle shape, and with these needle shape mullite forming a continuous network structure. The synthesizing temperature of mullite and activation energy decrease as mole ratio of Al/Si increases. Activation energy of synthesizing mullite decreases to (514.73 ± 14.40) kJ·mol-1 when mole ratio of Al/Si increases to 6:1.
杨中正, 姚亚刚, WONG C P, 陆跃军. 微沸法合成纳米莫来石及活化能的研究[J]. 材料工程, 2015, 43(6): 26-30.
YANG Zhong-zheng, YAO Ya-gang, WONG C P, LU Yue-jun. Activation Energy and Synthesis of Nano-mullite by Micro-boiling Method. Journal of Materials Engineering, 2015, 43(6): 26-30.
 REINHARD X,FISCHER H S,DIETMAR V. Formation of aluminum rich 9:1 mullite and its transformation to low alumina mullite upon heating [J]. Journal of the European Ceramic Society,1996, 16 (3): 109-113.
 MANUELA J A. Synthesis and phase transformations of mullites obtained from SiO2-Al2O3 gels [J]. Journal of the European Ceramic Society,1996, 16 (2): 781-789.
 杨中正, 赵顺波, 邢振贤, 等. 高铝矾土和煤矸石合成矾土基莫来石料的研究 [J]. 材料工程, 2010,(5): 51-55.YANG Zhong-zheng,ZHAO Shun-bo,XING Zhen-xian,et al.Preparation of bauxite-based homogenized mullite grogs with bauxite and coal gangue[J].Journal of Materials Engineering,2010,(5):51-55.
 BELHOUCHET H, HAMIDOUCHE M, TORRECILLAS R, et al. The non-isothermal kinetics of mullite formation in boehmite-zircon mixtures [J]. Journal of Thermal Analysis and Calorimetry, 2014, 116 (2): 795-803.
 BULJAN I, KOSANOVIA?C, KRALJ D. A novel synthesis of nano-sized mullite from aluminosilicate precursors [J]. Journal of Alloys and Compounds, 2011, 509 (32): 8256-8261.
 LI J H, MA H W, HUANG W H. Effect of V2O5 on the properties of mullite ceramics synthesized from high-aluminum fly ash and bauxite [J]. Journal of Hazardous Materials, 2009, 166 (2-3): 1535-1539.
 LI S, DU H, GUO A. Preparation of self-reinforcement of porous mullite ceramics through in situ synthesis of mullite whisker in fly ash body [J]. Ceramics International, 2012, 38 (2): 1027-1032.
 SEMBIRING S, SIMANJUNTAK W, MANURUNG P, et al. Synthesis and characterisation of gel-derived mullite precursors from rice husk silica [J]. Ceramics International, 2014, 40 (5): 7067-7072.
 SANAD M M S, RASHAD M M, ABDEL-AAL E A, et al. Effect of Y3+, Gd3+ and La3+ dopant ions on structural, optical and electrical properties of o-mullite nanoparticles [J]. Journal of Rare Earths, 2014, 32 (1): 37-42.
 WANG Y, CHENG H, LIU H, et al. Microstructure and room temperature mechanical properties of mullite fibers after heat-treatment at elevated temperatures [J]. Materials Science and Engineering: A, 2013, 578: 287-293.
 SARIN P, YOON W, HAGGERTY R P, et al. Effect of transition-metal-ion doping on high temperature thermal expansion of 3:2 mullite—An in situ, high temperature, synchrotron diffraction study [J]. Journal of the European Ceramic Society, 2008, 28 (2): 353-365.
 SCHNEIDER H, SCHREUER J, HILDMANN B. Structure and properties of mullite—A review [J]. Journal of the European Ceramic Society, 2008, 28 (2): 329-344.
 王法辉, 刘 莹. 莫来石纤维含量对陶瓷基摩擦材料摩擦磨损性能的影响 [J]. 材料工程, 2012, (12): 61-65. WANG Fa-hui,LIU Ying.Effects of mullite fiber content on friction and wear properties of ceramic-based friction material[J].Journal of Materials Engineering,2012,(12):61-65.
 WANG S, SHEN X Q, YAO H C, et al. Synthesis and sintering of pre-mullite powders obtained via carbonate precipitation [J]. Ceramics International, 2010, 36 (2): 761-766.
 SUEYOSHI S S,CONTRERAS-SOTO C A. Fine pure mullite powder by homogeneous precipitation [J]. Journal of the European Ceramic Society, 1998, 18 (2): 1145-1152.
 SANAD M M S, RASHAD M M, ABDEL-AAL E A, et al. Optical and electrical properties of Y3+ ion substituted orthorhombic mullite Y(x)Al(6-x) Si2O13 nanoparticles [J]. Journal of Materials Science: Materials in Electronics, 2014, 25 (6): 2487-2493.
 KUTTY T R N,NAYAK M. Photoluminescence of Eu2+-doped mullite (xAl2O3·ySiO2; x/y=3/2 and 2/1) prepared by a hydrothermal method [J]. J Materials Chemistry and Physics 2000, 65 (2): 158-165.
 YOSHIDA K, HYUGA H, KONDO N, et al. Synthesis of precursor for fibrous mullite powder by alkoxide hydrolysis method [J]. Materials Science and Engineering: B, 2010, 173 (1-3): 66-71.
 WANG W, WENG D, WU X. Structure evolution and thermal stability of La2O3-doped mullite fibers via sol-gel method [J]. Journal of Rare Earths, 2012, 30 (2): 175-180.
 GUO X, LI W, NAKANISHI K, et al. Preparation of mullite monoliths with well-defined macropores and mesostructured skeletons via the sol-gel process accompanied by phase separation [J]. Journal of the European Ceramic Society, 2013, 33 (10): 1967-1974.
 SANTANA L N L, GOMES J, NEVES G A, et al. Mullite formation from bentonites containing kaolinite: Effect of composition and synthesis parameters [J]. Applied Clay Science, 2014, 87: 28-33.
 RUIZ DE SOLA E, ESTEVAN F, ALARC N J. Low-temperature Ti-containing 3:2 and 2:1 mullite nanocrystals from single-phase gels [J]. Journal of the European Ceramic Society, 2007, 27 (7): 2655-2663.