Thermodynamics of the formation of magnesium–zinc intermetallic compounds in the temperature range from absolute zero to high temperature
Thermodynamics of the formation of magnesium–zinc intermetallic compounds in the temperature range from absolute zero to high temperature
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DOI：
10.1016/j.actamat.2006.03.004
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发表时间：
2006-06
期刊：
影响因子：
9.4
通讯作者：
M. Morishita;Hiroaki Yamamoto;Shinichi Shikada;Minoru Kusumoto;Y. Matsumoto
中科院分区：
文献类型：
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作者：
M. Morishita;Hiroaki Yamamoto;Shinichi Shikada;Minoru Kusumoto;Y. Matsumoto
首次用量热法测定了Mg-Zn二元化合物在近绝对零度至高温范围内的标准生成吉布斯自由能（ΔfGT_H）。用弛豫法和差示扫描量热法测定了它们从近绝对零度（2K）到高温的热容（Cp）。用溶液量热法测得的298 K时的标准生成焓（Δ fH 298 Ω）与Cp数据相结合，测定了它们的ΔfGT Δ H值。从接近绝对零度到300 K，ΔfGT Δ T值单调增加，然后在300 K以上，它们可以作为温度的线性函数计算如下（单位：kJmol−1）：ΔfGT（Mg48Zn52）=-12.15 102 +0.135T（±300）（300-530K）;ΔfGT（α-Mg2Zn3）=-69.95+1.15×10-2T（±20）（300-557.14K）;ΔfGT（β-Mg2Zn3）=-68.00+8.00×10−3T（±20）（557.14-640K）;ΔfGT ε（MgZn2）=-41.61+6.66×10−3T（±9）（300-680K）;ΔfGT ε（Mg2Zn11）=-118.17+2.67×10−2T（±39）（300-530K）。所得结果可望作为镁基合金的基本热力学数据。
The standard Gibbs energies of formation (ΔfGT∘) of Mg–Zn binary compounds in the temperature range from near absolute zero to high temperature were determined by calorimetry for the first time. Their heat capacities (Cp) from near absolute zero (2K) to high temperature were measured by the relaxation method and differential scanning calorimetry. Their ΔfGT∘values were determined by combining the Cpdata with the standard enthalpies of formation at 298K (ΔfH298∘) which were previously determined by solution calorimetry in hydrochloric acid solution. From near absolute zero to 300K, the ΔfGT∘values increase monotonically, and then above 300K they can be evaluated as a linear function of temperature as follows (in kJmol−1): ΔfGT∘(Mg48Zn52)=-12.15×102+0.135T(±300)(300–530K);ΔfGT∘(α-Mg2Zn3)=-69.95+1.15×10-2T(±20)(300–557.14K);ΔfGT∘(β-Mg2Zn3)=-68.00+8.00×10−3T(±20)(557.14–640K);ΔfGT∘(MgZn2)=-41.61+6.66×10−3T(±9)(300–680K);ΔfGT∘(Mg2Zn11)=-118.17+2.67×10−2T(±39)(300–530K). The results obtained are expected to be useful as basic thermodynamic data for Mg-based alloys.