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

Abstract

The crystallographic structures and surface morphologies of Fe-P binary alloy films electrodeposited at different bath concentration and different electrodeposition conditions have been studied in detail by means of XRD, HRTEM and SEM. The crystallization sequences of deposited films under the heat-treatment were analyzed with the help of XRD. The crystallographic structures of Fe-P deposited films were also compared with the Fe-P thermal equilibrium phase diagram. The results indicate that the crystallographic structures of Fe-P deposited films gradually change from crystalline to amorphous with increasing P content in the deposited films. The deposited film exists as α-Fe supersaturated solid solution when the P compositions in deposited film are below 20.5 at%, whereas it exists as a homogeneous amorphous phase when the P compositions in the deposited films are from 22.2 at% to 30.1 at%. Accordingly, the composition of boundary between the crystalline and homogeneous amorphous regions can be determined at about 21.4 at% P content.