Reaction Pathway of Combustion Synthesis of Ti ₅ Si ₃ in Cu–Ti–Si System

Abstract

The reaction pathway of combustion synthesis (CS) of Ti 5 Si 3 in Cu – Ti – Si system was explored through a delicate microstructure and phase analysis on the resultant products during differential thermal analysis ( DTA ). The formation of Cu – Si eutectic liquids plays a key role in the reaction pathway, which provides easy route for reactant transfer and accelerates the occurrence of complete reaction. Cu initially reacted with Si to form Cu 3 Si by a solid‐state diffusion reaction, which further reacted with Cu to form Cu – Si liquids at the eutectic point of ~802°C; then Ti was dissolved into the surrounding Cu – Si liquids and led to the formation of Cu – Ti – Si ternary liquids; finally, Ti 5 Si 3 was precipitated out of the saturated liquids by a solution–reaction–precipitation mechanism. The reaction pathway in CS of titanium silicide ( Ti 5 Si 3 ) could be described briefly as: Cu (s) + Ti (s) + Si (s) → Cu 3 Si (s) + Ti (s) + Si (s) →( Cu – Si ) (l) + Ti (s) →( Cu – Ti – Si ) (l) → Cu (l) + Ti 5 Si 3(s) .