Sublimation printing (physics)
The sublimation pressure is the pressure under which the gas phase of a solid substance is when the solid and gas are in thermodynamic equilibrium . The gas is formed from the solid by sublimation or, conversely, the solid is formed from the gas by resublimation . It should be noted that the substance sublimates directly into the gas phase or, conversely, solidifies from the gas phase without passing through the liquid phase. Pressure and temperature must be below the triple point , i.e. on the phase boundary line between gas and solid, the so-called sublimation pressure curve of a phase diagram . Since this has only one degree of freedom , the sublimation pressure and sublimation temperature are dependent on one another, which is expressed in the Clapeyron equation . The superordinate term saturation vapor pressure includes the sublimation pressure (solid / gaseous) and the boiling pressure (liquid / gaseous).
The fact that the sublimation pressure is always lower than the boiling pressure has the consequence, for example, that food in the refrigerator dries out and frost forms on the freezer compartment . The water evaporates from the food with a higher boiling pressure and then flows to the colder freezer compartment, where a lower sublimation pressure is set through resublimation.