TY - JOUR
T1 - The kinetic analysis of formation behavior for the MgB2 phase
AU - Yan, Shicheng
AU - Lu, Yafeng
AU - Liu, Guoqing
AU - Yan, Guo
AU - Zhou, Lian
PY - 2007/9/27
Y1 - 2007/9/27
N2 - By using differential scanning calorimetry (DSC) and X-ray diffraction (XRD), we have investigated the phase formation for the Mg-B system, where two kinds of alumina crucible, with a cover (denoted as sample A) and without cover (denoted as sample B), were used during measurements. Heating rates of 5, 10, 15 and 20 °C/min were employed in the DSC measurement for the mixed powder of Mg:B = 1:2. The DSC curves of sample A show that the Mg-B system undergoes three kinds of process; solid-solid, Mg melting, and liquid-gas-solid reaction with increasing temperature. But the DSC results of sample B present three changes of Mg melting, liquid-gas-solid reaction, and a possible oxidation process of MgB2. The difference between samples A and B was further investigated in a sintering experiment similar to the DSC process. The XRD analysis for the sintered samples indicates that the reaction between Mg and B to form MgB2 occurs easily in the Mg atmosphere. The activation energy of the solid-solid reaction for the Mg-B system was calculated by using the Ozawa-Flynn-Wall and Kissinger methods, and the calculated values are 58.18 and 72.75 kJ/mol, respectively. The calculated value of the pre-exponential factor is 2.0 × 1015 S-1. The relatively small value of E indicates that the reaction between Mg and B to form MgB2 occurs easily.
AB - By using differential scanning calorimetry (DSC) and X-ray diffraction (XRD), we have investigated the phase formation for the Mg-B system, where two kinds of alumina crucible, with a cover (denoted as sample A) and without cover (denoted as sample B), were used during measurements. Heating rates of 5, 10, 15 and 20 °C/min were employed in the DSC measurement for the mixed powder of Mg:B = 1:2. The DSC curves of sample A show that the Mg-B system undergoes three kinds of process; solid-solid, Mg melting, and liquid-gas-solid reaction with increasing temperature. But the DSC results of sample B present three changes of Mg melting, liquid-gas-solid reaction, and a possible oxidation process of MgB2. The difference between samples A and B was further investigated in a sintering experiment similar to the DSC process. The XRD analysis for the sintered samples indicates that the reaction between Mg and B to form MgB2 occurs easily in the Mg atmosphere. The activation energy of the solid-solid reaction for the Mg-B system was calculated by using the Ozawa-Flynn-Wall and Kissinger methods, and the calculated values are 58.18 and 72.75 kJ/mol, respectively. The calculated value of the pre-exponential factor is 2.0 × 1015 S-1. The relatively small value of E indicates that the reaction between Mg and B to form MgB2 occurs easily.
KW - Kinetic analysis
KW - MgB
KW - Phase formation
UR - http://www.scopus.com/inward/record.url?scp=34447271508&partnerID=8YFLogxK
U2 - 10.1016/j.jallcom.2006.11.133
DO - 10.1016/j.jallcom.2006.11.133
M3 - 文章
AN - SCOPUS:34447271508
SN - 0925-8388
VL - 443
SP - 161
EP - 165
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
IS - 1-2
ER -