Kinetics of Salt Creeping on a Free Surface: From Nucleation to Saturation

TL;DR

This study combines theoretical modeling, experiments, and simulations to comprehensively understand the kinetic regimes of salt creeping on free surfaces, from nucleation to saturation.

Contribution

It introduces a unified description of salt growth kinetics and explores microscopic crystal evolution under different environmental conditions.

Findings

Identified three kinetic regimes: exponential, linear, and logarithmic saturation.

Developed a theoretical model matching experimental observations.

Simulated microscopic crystal structures under varying humidity and temperature.

Abstract

The phenomenon of salt creeping along a free surface remains only partially understood, particularly with respect to its dynamics. In this work, combining a theoretical model with controlled experiments, we identify three distinct kinetic regimes: an initial exponential growth of the height of the crystallized salt deposit on vertical walls, followed by a linear regime, and a final stage where the height saturates while the crystal deposit thickens logarithmically. This unified description makes it possible to follow the macroscopic kinetics of salt growth on a free surface from its nucleation to saturation. In addition, we complement this macroscopic analysis with numerical simulations that shed light on the evolution of the microscopic crystal structure under varying external conditions (humidity and temperature).