Peritectic and Peritectoid Systems

Schematic showing the construction of a peritectic phase diagram from free energy curves. 

Pb-Bi system. There is a peritectic reaction at 187°C with composition 30 At% Bi. There is also a eutectoid reaction at -46°C with 27.5 At% Bi. (Reprinted from Massalski, T.B., Handbook ( Binary AUoy Phase Diagrams, ASM, 1990. Reprinted with permission of ASM International. All rights reserved.) 

Peritectic-like reactions can also occur in solids in which two components react at a specific temperature and composition to form a third component or a + (3 7. Such 

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