Phase diagram can be constructed that show the effect of more than two variables on the phase of a substance. Phase diagrams can use other variables in addition to or in place of temperature, pressure and composition, for example the strength of an applied electrical or magnetic field, and they can also involve substances that take on more than just three states of matter. One type of phase diagram plots temperature against the relative concentrations of two substances in a mixture called a "binary phase diagram", as shown at right. Such a mixture can be either a solid solution, eutectic or peritectic,
Solidus (chemistry) not coincide. If a gap exists between the solidus and liquidus it is called the freezing range, and within that gap, the substance consists of a mixture of solid and liquid phases (like a slurry). Such is the case, for example, with the olivine (forsterite-fayalite) system. In eutectic mixtures the solidus and liquidus temperatures coincide at a point known as the eutectic point. At the eutectic point, the solid congruently melts (i.e., melts completely). Solidus (chemistry) In chemistry, materials science, and physics, the solidus is the locus of temperatures (a curve on a phase diagram) below which a given substance