Electrodeposited Rare Earth-Iron Group Metal Alloy Films And Magnetic Properties In Urea Molten Salts

Rare earth (RE) - iron group metal (IG) alloy films have excellent magnetic, optical and electric properties, they have been investigated for many years for applications as electron, information technology, energy, and so on. Moreover, electrodeposition is an alternative method for preparing these alloy films. It has the advantage of being simple and cost-effectivenes, utilizing easily maintained equipment. Deposits can also be tailored through changing solution composition and deposition conditions. In this thesis, consequently, we have been prepared Rare earth (RE=La,Sm,Gd) - iron group metal (IG=Fe,Co,Ni) alloy films in low temperature urea-acetamide-NaBr-KBr-RECl₃-IGCl₂ baths by potentiostatic electrolysis. The electrochemical behavior and co-deposition mechanism were investigated. The phase structure and magnetic properties before and after heat-treatment were studied in detail. The main contents of this paper are arranged as follows:1. The development and application of RE-IG alloy films, the preparation method for electrodepositied RE-IG alloy films, the essential conception and sort of magnetic theory and the equipments for electrodeposition and test were introduced in brief, respectively.2. Cyclic voltammetry was used to investigate the electrochemical behavior of RE³⁺ and IG²⁺ in baths on a Pt electrode. The transfer coefficientαand the diffusion coefficient D₀ for IG²⁺ were measured, respectively. The co-deposition mechanism was explained well with the electronegativity theory. Finally, the dependence of composition and morphology of alloy films on electrodepositon conditions was investigated.3. The change trend of magnetic properties for amorphous RE-IG alloy films in urea molten salt was concluded firstly. The phase structure and magnetic properties after the best heat-treatment were studied.