1. 1) Z.C. Cao, T.C. Sun, H.F. Yang, J.J. Wang and X.D. Wu: J. Univ. Sci. Technol. Beijing 32 (2010) 708–712.
2. 2) C.M. Zhao and Y.C. Zhai: School of Materials and Metallurgy Northeastern University 23 (2009) 73–76.
3. 3) C.Y. Wang, F. Yin, Y.Q. Chen, Z. Wang and J. Wang: Beijing General Research Institute of Mining & Metallurgy 18 (2008) s1–s8.
4. 4) W. Liang, H. Wang, J.G. Fu and Z.X. He: Journal of Central South University 42 (2011) 2173–2177 (Science and Technology).
5. 5) M.J. Rao, G.H. Li, T. Jiang, J. Luo, Y.B. Zhang and X.H. Fan: J. o. M. 65 (2013) 1573–1583.