The Transient Growth of Ammonium Chloride Dendrites

TL;DR

This paper investigates the initial growth, transient response, and steady-state behavior of ammonium chloride dendrites from supersaturated solutions, revealing consistent growth parameters and differing dissolution characteristics.

Contribution

It provides new measurements of dendritic growth dynamics and transient responses, highlighting the stability of growth parameters and differences during dissolution.

Findings

Growth speed and tip radius reach steady state independent of seed size

Dendrites quickly adapt to temperature changes while maintaining constant growth parameters

Dissolving dendrites do not follow the same growth parameter values

Abstract

We report measurements of the initial growth and subsequent transient response of dendritic crystals of ammonium chloride grown from supersaturated aqueous solution. Starting from a small, nearly spherical seed held in unstable equilibrium, we lower the temperature to initiate growth. The growth speed and tip radius approach the same steady state values independent of initial seed size. We then explore the response of the growing dendrite to changes in temperature. The crystal adjusts quickly and smoothly to the new growth conditions, maintaining an approximately constant value of $v \rho ^2$ throughout. Dissolving dendrites, on the other hand, are not characterized by the same value of $v \rho ^2$.