The Gibbs phase rule for binary phase diagram F C P + 1 gives the relationship between the number of phases p and components c in a given alloy under equilibrium conditions at constant pressure.

We therefore usually choose to plot both P (pressure) and T (temperature) since composition is not a variable Examples Water Silica Carbonį = c - p + 2 = 1- p + 2 = 3 - p If one phase is present, there are two degrees of freedom (both T and P) If two phases are present, there is one degree of freedom (either T or P) If three phases are present, there are no degrees of freedomħ Silica Phase Diagram Image: silica-phase-diag.gifĨ Snowflake Obsidian The white patches are crystals of cristobolite, formed at high temperature The magma-crystal mix then erupted, chilling the magma and forming a volcanic glass matrix around the metastable cristobolite, which cooled too quickly to revert to tridymite Source:ĩ Carbon Phase Diagram Image: Carbon_Phase_Diagram.gifįrom David Archer, Global Warming, figure 7. A binary phase diagram shows the phases formed in differing mixtures of two elements over a range of temperatures. Download as PDF, TXT or read online from Scribd.

2 Unary Diagrams Unary diagrams have a single component Phase Diagrams are also known as Equilibrium Diagrams Rate of Transformation.

Binary phase diagram online