Effect of Na ions in plating baths on coercivity of electroplated Fe-Pt film-magnets

• Published in: Journal of Alloys and Compounds Vol. 752; pp. 133 - 136
• Main Authors: Yanai, T., Honda, J., Hamamura, R., Yamada, H., Fujita, N., Takashima, K., Nakano, M., Fukunaga, H.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 05.07.2018; Elsevier BV
• Subjects: Annealing; Coercivity; Direct current; Electroplating; Fe-Pt; Film magnet; Hard magnetic material; Ion concentration; Ions; Magnetic properties; Magnetism; Magnets; Na ion concentration; pH; Plating; Plating baths; Sodium; Sodium chloride; Sodium citrate; Substrates; Tantalum; Thick films; Film magnet; pH; Fe-Pt; Electroplating; Na ion concentration; Hard magnetic material
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2018.04.126

Fe50Pt50 thick-films were electroplated on a Ta substrate using a direct current, and we evaluated the effect of Na ion concentration in plating baths on the magnetic properties of the annealed films. With increasing NaCl content from 2 to 30 g/L, the coercivity of the annealed Fe50Pt50 films increased from 700 kA/m to approximately 900 kA/m. For obtaining further experimental evidence for the increase in the coercivity, we employed trisodium citrate instead of NaCl as an additive in the plating bath. Consequently, as the addition of the trisodium citrate as well as NaCl increased the coercivity, we concluded that a plating bath with high Na ion concentration is effective to obtain the Fe-Pt thick-films with high coercivity. •High Na ion concentration tend to show high coercivity on theFe50Pt50films.•The grain size of the annealed one decrease with increasing the Na ion concentration.•Na ion prevents grain growth during annealing for the ordering crystalline phase.