Phase transformation sequence of amorphous ferrochrome alloy electrodeposit

A series of ferrochrome alloy layers with different iron contents are electrodeposited. The phase transformation sequences of the electrodeposited Cr-29.51 wt% Fe alloy layer upon heat treatment are studied in detail. X-ray diffraction analysis shows that as the iron content of the layer increases, the ferrochrome alloy layer changes from a crystalline structure of a substitutional solid solution, then to a mixed-structure of amorphous and crystalline, and finally to an amorphous structure. The differential scanning calorimetry curves at heating rates ranging from 5 °C/min to 20 °C/min, accompanied with the heat treatment, indicate that the layer starts the first crystallization at around 692.45–722.15 K and then precipitates new phases of Cr 2 O 3 and Cr 23 C 6 at around 870.35–895.95 K. Their apparent activation energies are 172.1 ( E a1 ) for the crystallization and 341.6 kJ/mol ( E a2 ) for the new phase precipitation, respectively. After the heat treatment, the iron content on the surface of the layer is significantly reduced while the O strongly increased.