The Dealloying Kinetics of Ag(25)Zn(75) in 0.1 M H(2)SO(4)

Ag(25)Zn(75) alloy was dealloyed in 0.1 M H(2)SO(4) at a potential of 0.4 V left perpendicularsaturated KCl calomel electrode (SCE)right perpendicular, and a bicontinuous porous Ag was obtained. With increasing dealloying time, both the sizes of the pores and the ligaments increase and the cracks on the surface become broader and denser. The time dependence of the thickness of porous Ag agrees with the linear relationship h(mu m) = 28t(h) + 15 (t >= 1 h), which could be well calculated by the time dependence of the electric current density as soon as the macroscopic shrinkage during dealloying is taken into account. According to the relationship between pore radius and dealloying time r = bt(0.25), the surface diffusivity of Ag in 0.1 M H(2)SO(4) at 0.4 V (SCE) could be approximately fitted as 1.9 x 10(-12) cm(2) s(-1). (C) 2010 The Electrochemical Society. [DOI:10.1149/1.3481429] All rights reserved.