Study on preparation of NiFeP films by pulse electrodeposition

Abstract

Ultrasonic was introduced during pulse plating process to prepare NiFeP alloy films. Effects of different duty ratios and ultrasonic powers on composition, microstructure and magnetic properties of films were investigated. With the rise in duty ratios, the amount of nickel increased gradually. Higher ultrasonic power could result in larger contents of iron in NiFeP alloy films. That was because nickel reduction was potential controlled while iron reduction was diffusion controlled during the pulse plating process. Almost all the deposited films were crystalline and formed peaks of FeNi₃ (111), FeNi₃ (200) and FeNi₃ (220). With the increase in duty ratios, the intensity of all three peaks started to decline, which led to worse crystalline and bigger grain sizes. Dissimilar surface morphology could be detected by the condition of different duty ratios and ultrasonic powers. NiFeP films with smaller grain size and smooth surface could be obtained when a higher power of ultrasonic was introduced during the pulse plating process. However, the films with rough and agglomerate nodular structures would be observed with higher duty ratios. Vibration sample magnetometer results showed that the coercivity of NiFeP films ranged from 30 to 150 Oe.