Relationship between the crystallographic structure of electrodeposited Fe-Cr alloy film and its thermal equilibrium diagram

Abstract

The crystallographic structure and morphology of electrodeposited Fe-Cr films under different bath conditions were studied in detail by using XRD, HRTEM and SEM. The crystallographic structures of the Fe-Cr electrodeposits were also compared with the Fe-Cr thermal equilibrium diagram. The results indicated that the crystallographic structure of electrodeposited Fe-Cr alloy film gradually changed from microcrystalline to amorphous with increasing Cr content. The deposited film exists as α-Fe solid solution when the Cr compositions of deposited films are below 3.1 at%, whereas, it existed as a meta-stable crystal when the Cr compositions of deposited films are from 4.5 at% to 22.4 at%, which have not been reported up to now. The deposited films with various Cr compositions from 22.9 at% to 74.4% chromium exist as amorphous phase. Hence, the crystallographic structure of the electrodeposited Fe-Cr alloy film is closely related to its thermal equilibrium diagram, but does not always agree with it.