Melting behaviour

Melting behaviour describes how a substance transitions from a solid to a liquid state when heated and what thermal and rheological properties occur during this process. It encompasses the melting point or melting range, the enthalpy of fusion, the viscosity of the melt, as well as the flow and solidification behaviour.

In process engineering, melting behaviour is a key design parameter for thermal processes such as heating, mixing, reacting, extruding or coating. Particularly in the case of powders, fats, polymers, waxes or bulk materials with a partial melting phase, it influences heat transfer, miscibility, agglomeration and product structure.

However, there are also substances that do not melt when heated, but instead transition directly from the solid to the gaseous state. This process is known as sublimation. Sublimating substances may also be present as powders, for example dry ice, certain organic compounds or active pharmaceutical ingredients. For such products, sublimation behaviour is relevant to the process rather than melting behaviour.