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The Influence of Al and Si Additives on the Microstructure and Mechanical Properties of Low-Carbon MgO-C Refractories
T.B. Zhu1, Y.W. Li1, S.B. Sang1, S.L. Jin2
1 The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, 430081 Wuhan, PR China
2 Chair of Ceramics, Montanuniversitaet Leoben, A-8700 Leoben, Austria
received September 2, 2015, received in revised form November 1, 2015, accepted January 7, 2016
Vol. 7, No. 1, Pages 127-134 DOI: 10.4416/JCST2015-00055
Abstract
The mechanical properties of low-carbon MgO-C refractories strongly depend on the formation of ceramic phases (e.g. their amounts, distribution and morphologies) in the matrix. In the present work, the influence of Al and Si additives on the phase composition, microstructure and mechanical properties of low-carbon MgO-C refractories (1 wt% flaky graphite) was investigated by means of X-ray diffraction, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, three-point bending and thermal shock tests. The results showed that Al4C3 whiskers and MgAl2O4 particles formed in-situ in the specimens after firing at 1000 °C and 1200 °C when Al and Si additives were incorporated simultaneously into the specimens. Up to 1400 °C, many SiC whiskers and plate-like AlN as well as MgAl2O4 in the form of hollow MgO-rich whiskers and particles appeared. However, few SiC whiskers and many Mg2SiO4 particles existed in the specimen fired at 1200 °C and lots of Mg2SiO4 particles formed at 1400 °C when Si powder was used as the additive. These ceramic phases unquestionably influenced the mechanical properties of low-carbon MgO-C refractories. Improved mechanical properties and thermal shock resistance were achieved for the specimen with Al and Si additives compared with those of the specimen containing Si powder.
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Keywords
In-situ-formed ceramic phases, mechanical properties, thermal shock resistance, MgO-C refractories
References
1 Hayashi, S., Takahashi, H., Watanabe, A., Osaka, A., Miura, Y.: Dependence of mechanical properties of MgO-C bricks on graphite content, J. Ceram. Soc. Jpn., 102, 23 – 28, (1994).
2 Zhang, S., Marriott, N.J., Lee, W.E.: Thermochemistry and microstructures of MgO-C refractories containing various antioxidants, J. Eur. Ceram. Soc., 21, 1037 – 1047, (2001).
3 Ewais, E.M.M.: Carbon based refractories, J. Ceram. Soc. Jpn., 112, 517 – 532, (2004).
4 Bae, I., Kim, M., Chung, D., Shin, M., Seo, Y.: The improvement of MgO-C bricks toughness for RH snorkels, in: Proceedings of UNITECR'05 Congress, Orlando, USA, (2005).
5 Bag, M., Adak, S., Sarkar, R.: Study on low carbon containing MgO-C refractory: use of nano carbon, Ceram. Int., 38, 2339 – 2346, (2012).
6 Zhu, B.Q., Zhang, W.J., Yao, Y.S.: Current situation and development of low-carbon magnesia-carbon materials research, Refractories, 40, [1], 90 – 95, (2006).
7 Zhu, T.B., Li, Y.W., Sang, S.B., Jin, S.L., Li, Y.B., Zhao, L., Liang, X.: Effect of nanocarbon sources on microstructure and mechanical properties of MgO-C refractories, Ceram. Int., 40, 4333 – 4340, (2014).
8 Baudin, C., Alvarez, C., Moore, R.E.: Influence of chemical reactions in magnesia-graphite refractories: I, Effects on texture and high-temperature mechanical properties, J. Am. Ceram. Soc., 82, 3529 – 3538, (1999).
9 Baudin, C., Alvarez, C., Moore, R.E.: Influence of chemical reactions in magnesia-graphite refractories: II, Effects of aluminum and graphite contents in generic products, J. Am. Ceram. Soc., 82, 3539 – 3548, (1999).
10 Aneziris, C.G., Hubalkova, J., Barabas, R.: Microstructure evaluation of MgO-C refractories with TiO2- and Al-additions, J. Eur. Ceram. Soc., 27, 73 – 78, (2007).
11 Fan, H.B., Li, Y.W., Huang, Y.P., Sang, S.B., Li, Y.B., Zhao, L.: Microstructures and mechanical properties of Al2O3-ZrO2-C refractories using silicon, microsilica or their combination as additive, Mater. Sci. Eng. A, 545, 148 – 154, (2012).
12 Fan, H.B., Li, Y.W., Sang, S.B.: Microstructures and mechanical properties of Al2O3-C refractories with silicon additive using different carbon sources, Mater. Sci. Eng. A, 528, 3177 – 3185, (2011).
13 Zhu, T.B., Li, Y.W., Luo, M., Sang, S.B., Wang, Q.H., Zhao, L., Li, Y.B., Li, S.J.: Microstructure and mechanical properties of MgO-C refractories containing graphite oxide nanosheets (GONs), Ceram. Int., 39, 3017 – 3025, (2013).
14 Zhu, T.B., Li, Y.W., Jin, S.L., Sang, S.B., Wang, Q.H., Zhao, L., Li, Y.B., Li, S.J.: Microstructure and mechanical properties of MgO-C refractories containing expanded graphite, Ceram. Int., 39, 4529 – 4537, (2013).
15 Xie, Z.H., Ye, F.B.: Effects of ferrocene on microstructure of MgO-C refractories matrix, Mater. Rev., 23, [5], 115 – 118, (2009).
16 Xie, Z.H., Ye, F.B.: In-situ formation of spinel fibers in MgO-C refractory matrixes, J. Wuhan Univer. Tech.-Mater. Sci. Ed., 24, [6], 896 – 902, (2009).
17 Zhu, B.Q., Wei, G.P., Li, X.C., Ma, Z., Wei, Y.: In-situ catalytic growth of MgAl2O4 spinel whiskers in MgO-C refractories, Int. J. Mater. Res., 105, [6], 593 – 598, (2014).
18 Zhu, T.B., Li, Y.W., Jin, S.L., Sang, S.B., Liao, N.: Catalytic formation of one-dimensional nanocarbon and MgO whiskers in low carbon MgO-C refractories, Ceram. Int., 41, 3541 – 3548, (2015).
19 Uchida, S., Ichikawa, K., Niihara, K.: High-temperature properties of unburned MgO-C bricks containing Al and Si powders, J. Am. Ceram. Soc., 81, 2910 – 2916, (1998).
20 Li, Y.W., Chen, X.L., Sang, S.B., Li, Y.B., Jin, S.L., Zhao, L., Ge, S.: Microstructures and properties of carbon refractories for blast furnaces with SiO2 and al additions, Metall. Mater. Trans. A., 41A, 2085 – 2092, (2010).
21 Bale, C.W., Bélisle, E., Chartrand, P., Decterov, S.A., Eriksson, G., Hack, K., Jung, I.-H., Kang, Y.-B., Melancon, J., Pelton, A.D., Robelin, C., Petersen, S.: FactSage thermochemical software and databases – recent developments, Calphad, 33, [2], 295 – 311, (2009).
22 Chen, X.L, Li, Y.W., Li, Y.B., Jin, S.L., Zhao, L., Ge, S.: Effect of temperature on the properties and microstructures of carbon refractories for blast furnace, Metall. Mater. Trans. A, 40A, 1675 – 1683, (2009).
23 Zhu, T.B., Li, Y.W., Sang, S.B., Jin, S.L., Wang, H.: Formation of hollow MgO-rich spinel whiskers in low carbon MgO-C refractories with al additives, J. Eur. Ceram. Soc., 34, 4425 – 4432, (2014).
24 Li, Y.W., Jin, S.L., Liu, G.T., Zhang, W.H., Ao, J.Q., Li, Z.Y.: Behavior of magnesium and silicon in the formation of MgO/AlN composite, J. Mater. Sci., 44, 4155 – 4161, (2009).
25 Kumari, S.S.S., Pillai, U.T.S., Pai, B.C.: Synthesis and characterization of in situ Al-AlN composite by nitrogen gas bubbling method, J. Alloy. Compd., 509, 2503 – 2509, (2011).
26 Tamura, S., Ochiai, T., Takanaga, S., Kanai, T., Nakamura, H., Goto, K., Hanagiri, S.: Nano-tech. refractories-8: technological philosophy and evolution of nano-tech. refractories, in: Proceedings of UNITECR'11 Congress, Kyoto, Japan, (2011).
27 Tamura, S., Ochiai, T., Takanaga, S., Matsuura, O., Yasumitsu, H., Hirashima, M.: Development of MgO-C nano-tech refractories of 0 % graphite content (Nano-Tech refractories-12), in: Proceedings of UNITECR'13 Congress, Victoria, Canada, (2013).
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