水绿矾的状态方程和高压熔化

 用阻抗匹配法和压电探针技术测量了初始密度为1.714 g/cm³（孔隙率α=ρ₀/ρ₀₀=1.898/1.714=1.107）的水绿矾（FeSO₄·7H₂O）的冲击压缩线，发现其在0～100 GPa范围内存在两个明显相区：含有部分熔融的低压相和完全熔化的高压相。在两个相区内，冲击波速度D和波后粒子速度u可分别描述为：D=0.59+2.06u（u<3.12 km/s）和D=3.18+1.223u（u≥3.12 km/s）。从冲击压缩数据出发，用欧拉有限应变理论得到了其等熵状态方程。其熔化方程可用p_m(GPa) =0.159(T_m(K)/1000)^6.3371+0.69来近似描述。

SHOCK WAVE EQUATION OF STATE AND SHOCK-INDUCED MELTING OF MELANTERITE

Shock compression experiments were conducted on melanterite samples with an initial density of 1.714 g/cm³ up to 100 GPa. The experimental data can be divided into a low-pressure region consisting of a partially molten state, and a completely liquid state at high-pressure. The shock velocity D is a linear function of the particle velocity u in these two regimes: D=0.59+2.06u for u<3.12 km/s and D=3.18+1.223u for u≥3.12 km/s. K_0S and K_0S´, the zero pressure adiabatic bulk modulus and its first pressure derivative of Birch-Murnaghan EOS (isentrope), are obtained in terms of shock Hugoniot data by using the Eulerian finite strain theory. Under the assumption γ=3.12(ρ₀/ρ), then for the low pressure phase (ρ₀=1.898 g/cm³), K_0S=3.72 GPa and K_0S´=4. We find ρ₀=1.60 g/cm³, K_0S=3.28 GPa and K_0S´=10.5 for the high pressure phase (liquid state), with a STP melting energy of 80 J/g and γ=1.46(ρ₀/ρ). The melting curve of melanterite is determined according to Lindemann's law and can be approximately described as: p_m(GPa) =0.159(T_m(K)/1000)^6.3371+0.69.