sublimaation

Sublimaation is a phase transition in which a solid substance changes directly into a gas without passing through a liquid state. This occurs when the solid has a nonzero vapor pressure at temperatures at or below its melting point and the surrounding pressure is low enough that the vapor can escape. A common example is dry ice (solid carbon dioxide), which sublimes at room temperature and atmospheric pressure, producing visible fog from water vapor in the air.

Other substances that sublimate include iodine, naphthalene, camphor, and certain frozen solutions under appropriate conditions. Sublimation rates depend on temperature, ambient pressure, surface area, and impurities. In industrial and scientific contexts, sublimation is exploited in processes such as freeze-drying (lyophilization), where water is removed from a material by sublimation under reduced pressure, preserving structure and nutrients.

Applications and related processes include purification and separation, where compounds are isolated based on differences in volatility. Sublimation is also used in thin-film deposition and coating techniques in materials science and electronics, where a material transitions from solid to gas and then re-deposits as a solid on a cooler surface.

In psychology, sublimation denotes a defense mechanism in which unacceptable impulses are transformed into socially acceptable or productive activities, such as artistic or scientific work. This usage is metaphorical and distinct from the physical process; it is debated and treated as a theoretical concept within psychoanalytic and broader psychological literature.