水绿矾的状态方程和高压熔化

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

用阻抗匹配法和压电探针技术测量了初始密度为 1.714g/cm3(孔隙率α =ρ0 / ρ0 0 =1.898/ 1.714 =1.10 7)的水绿矾 (FeSO4 ·7H2 O)的冲击压缩线 ,发现其在 0～ 10 0GPa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 .5 9+2 .0 6u(u <3.12km/s)和D =3.18+1.2 2 3u(u≥ 3.12km/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pm(GPa) =0 .15 9(Tm(K) / 10 0 0 ) 6.3371+0 .69来近似描述。

Shock compression experiments were conducted on melanterite samples with an initial density of 1.714g/cm 3 up to 100GPa.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+2.06 u for u <3.12km/s and D =3.18+1.23 u for u ≥3.12km/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(ρ 0/ρ ),then for the low pressure phase ( ρ 0=1.898g/cm 3), K 0S =3.72GPa and K ′ 0S =4.We find ρ 0=1.60g/cm 3, K 0S =3 28GPa and K ′ 0 S =10.5 for the high pressure phase (liquid state),with a STP melting energy of 80J/g and γ =1.46( ρ 0/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.