Effect of Electrolyte Composition on Corrosion Resistance in Nickel Plating Process for Coating Bonded Magnet PrFeB

Abstract

Despite of its excellence magnetic quality, one of the critical properties of PrFeB based permanent magnet is a low corrosion resistance so it can be oxidized easily which can reduce its magnetic properties. In this study, Nickel coating has been performed for bonded PrFeB magnet by the electroplating method using Nickel-Watts bath-type as the electrolyte to improve the corrosion resistance. The varying amount of the electrolyte compounds used to have the optimized composition indicated by the corrosion resistance measurement. The solution composition used was NiSO4 (230-380 g/L), NiCl2 (30-60 g/L), and H3BO3 (30 and 45 g/L) with a fixed value of other parameters. Characterization used including the immersion corrosion test, microstructure analysis, and magnetic properties. Based on the corrosion rate measurement, the highest corrosion resistant of Nickel coated PrFeB magnet achieved from the electrolyte composition of NiSO4: NiCl2: H3BO3 = 380: 60: 30 g/L with a plating time and current density (J) of 60 minutes and 40 mA/cm2 respectively. The corrosion rate data showed that the Nickel metal coating can improve the corrosion resistance of bonded PrFeB magnet up to 29 times than of the substrate. The SEM images showed that the thickness of the Nickel coating on the optimum electrolyte composition was in average value of 35.1 µm. The overall samples has a magnetic remanence value (Br) reached ≥ 6 kG, so it has enough properties to be applied in devices such as generators and electric motors.

Electronic Structure Insights into the Solvation of Magnesium Ions with Cyclic and Acyclic Carbonates

“…The selection and optimization of an appropriate electrolyte is an important consideration for ab road range of energy frontiers, such as electrochemical storaget echnologies, [1] dye-sensitized solar cells, [2] photo-/electrocatalytic processes, [3] electrodeposition, and corrosion. [4] In general,t he development of next-generation electrolytes for any target application is catered towards improving performance, and the screening criteria are often based on evaluating the trends in suitable descriptors. There are an umber of thermodynamic (solubility, chemicale quilibrium, and so forth) and kinetic descriptors (ion mobility,v iscosity and so forth), electrochemical, thermal, and mechanical stability, (electrochemical window,t emperature/ pressure parameters), and safety aspects that can be used to screen electrolytes depending on the desired function.…”

“…For example, battery applicationsprefer solvents with good solubility for the intercalating ion, [1] whereas corrosion requiress olvents with poor solubility for the aggressivei ons. [4] The success of electrolyte optimization strategies, therefore, hingess trongly on gaining ac omprehensive understanding of interactions on the atomistic level and their correlation with variouse lectrolyte properties, such as electrochemical stability,solvation structure, and dynamics.…”

“…[4] In general,t he development of next-generation electrolytes for any target application is catered towards improving performance, and the screening criteria are often based on evaluating the trends in suitable descriptors. There are an umber of thermodynamic (solubility, chemicale quilibrium, and so forth) and kinetic descriptors (ion mobility,v iscosity and so forth), electrochemical, thermal, and mechanical stability, (electrochemical window,t emperature/ pressure parameters), and safety aspects that can be used to screen electrolytes depending on the desired function.…”