非平衡界面动力学理论

王海丰, 蒲振新, 张建宝

Non-Equilibrium Interface Dynamics Theory

WANG Haifeng, PU Zhenxin, ZHANG Jianbao

图4 非稳态固/液界面动力学过程的摩尔Gibbs自由能示意

Fig.4 Mole Gibbs free energy diagram for the solid/liquid interface kinetic processes under a non-steady-state condition (Total Gibbs free energy dissipated by the interface after solidification of 1 mol liquid is $Δ G_{t o t a l}$ = $(1 - C_{t r a n s}) Δ μ_{A}^{*} + C_{t r a n s} Δ μ_{B}^{*}$ . By translating the tangent of Gibbs free energy curve of solid at $C_{S}^{*}$ to the Gibbs free energy curve of liquid at $C_{L}^{*}$ , $Δ$ G_total is divided into two parts: The upper one for trans-interface diffusion is $Δ G_{D}$ = $(C_{L}^{*} - C_{t r a n s}) (Δ μ_{A}^{*} - Δ μ_{B}^{*})$ and latter part for interface migration is $Δ G_{m}$ = $(1 - C_{L}^{*}) Δ μ_{A}^{*} + C_{L}^{*} Δ μ_{B}^{*}$ . The difference in $Δ$ G_total between the steady-state condition and the non-steady-state condition is $Δ G^{t r a n s ‐ S}$ = $(C_{t r a n s} - C_{S}^{*}) (Δ μ_{A}^{*} - Δ μ_{B}^{*})$ , which is the Gibbs free energy dissipated to adjust the actual composition transferred across the interface from $C_{S}^{*}$ to C_trans ( $C_{t r a n s}$ —the solute component that finally crosses the interface and enters the solid phase)