Stress-enhanced ion diffusion at the vicinity of a crack tip as evidenced by atomic force microscopy in silicate glasses

Informations Contextuelles

The slow advance of a crack in soda-silicate glasses was studied at nanometer scale by in-situ and real-time atomic force microscopy (AFM) in a well-controlled atmosphere. An enhanced diffusion of sodium ions in the stress-gradient field at the sub-micrometric vicinity of the crack tip was revealed through several effects: growth of nodules in AFM height images, changes in the AFM tip–sample energy dissipation. The nodules patterns revealed a dewetting phenomenon evidenced by ‘breath figures’. Complementary chemical micro-analyses were done. These experimental results were explained by a two-step process: (i) a fast migration (typical time: few milliseconds) of sodium ions towards the fracture surfaces as proposed by Langford et al. [J. Mat. Res. 6 (1991) 1358], (ii) a slow backwards diffusion of the cations as evidenced in these AFM experiments (typical time: few minutes). Measurements of the diffusion coefficient of that relaxing process were done at room temperature. Our results strengthen the theoretical concept of a near-surface structural relaxation due to the stress-gradient at the vicinity of the crack tip. The inhomogeneous migration of sodium ions might be a direct experimental evidence of the presence of sodium-rich channels in the silicate structure [A. Meyer et al., Phys. Rev. Let. 93 (2004) 027801].

Célarié F., Ciccotti M. and Marlière C, 2007. Stress-enhanced ion diffusion at the vicinity of a crack tip as evidenced by atomic force microscopy in silicate glasses.. J. Non-Crist. Solids.. 353, pp. 51-68.

Haut de page



À lire aussi...

The crack tip : a nanolab for studying confined liquids

Grimaldi A., George M., Pallares G., Marlière C. and Ciccotti M., 2008. The crack tip : a nanolab for studying confined liquids. Physical Review (...) 

> Lire la suite...

Imaging the stick-slip peeling of an adhesive tape under a constant load

Cortet P.-P., Ciccotti M. and Vanel L., 2007. Imaging the stick-slip peeling of an adhesive tape under a constant load.. J. Stat. Mech.. Art No. (...) 

> Lire la suite...