During a crystallization process, the size of the nuclei formed plays a crucial role in determining the final properties of the crystal. The size of the nuclei formed is affected by various factors, including the level of superheating of the initial liquid phase.
Superheating (∆T) refers to the increase in temperature of a liquid above its boiling point without the liquid phase changing into gas. This increase in temperature increases the amount of thermal energy available in the system and as a result, reduces the surface tension of the liquid between the atoms and molecules, allowing them to move more freely and form larger nuclei.
As the Superheating (∆T) increases, the second law of thermodynamics dictates that entropy must increase in the system, leading to an increase in the size of the nuclei groups formed. The increase in nuclei size then leads to a decrease in nucleation rate, or the number of new nuclei formed per unit time, resulting in the growth of fewer, larger nuclei. This in turn affects the crystal size and properties, as larger crystals tend to possess different and usually more desirable physical properties.