Magnetic properties of plasma electrolytic iron-containing oxide coatings on aluminum

The effect of nanocrystallites in the pores of PEO coatings on their magnetic properties

“…The first is one-stage PEO technique when precursors of magneto-active compounds are directly involved into forming electrolyte as complex compounds ([Co(EDTA)] − [5], [Fe(P 6 O 18 )] 3 − [14]) or in the compositions of solid micro-and nanosized particles (Fe 0 , Co 0 or Fe 2 O 3 ) [1,4]. Furthermore, the conditions for the formation of solid particles can be created directly in the electrolyte for PEO, for example, as a result of iron or cobalt hydroxide precipitation in phosphate-borate-tungstate solution after addition of appropriate oxalate or acetate [3,14,15] and their hydrolysis in alkaline medium. During PEO the dispersed (colloidal) particles of negatively charged metal hydroxides were maintained in suspended state by stirring the electrolyte.…”

“…Upon one-stage PEO technique the magneto-active elements are concentrated in the pores [3,5] or the defects of the surface [14]. In this case the simulation showed [19] that the composites 'Fe-containing PEO coating/valve metal' can have ferromagnetic clusters which consist of chemically inhomogeneous particles or a mixture of particles with very different magnetic properties.…”

“…To obtain such composites one can use plasma electrolytic oxidation (PEO) technique [1,[3][4][5] that is electrochemical oxidation of valve metals under spark and microarc electric discharges [6][7][8][9][10][11][12][13].…”

Magnetic characteristics of iron-modified oxide layers on titanium

“…In recent years, it has been shown that iron and/or cobalt containing oxide coatings with ferro , ferri , or antiferromagnetic properties can be formed on alumi num or titanium substrates by an unconventional sin gle stage method: anodization in aqueous electrolytes at sparking and microarcing voltages (microarc or plasma electrolytic oxidation, PEO) [1][2][3][4][5][6][7][8][9]. Precursors containing cobalt or iron compounds are introduced into electrolytes either in the composition of solid micro and nanoparticles (Fe 0 , Co 0 , or Fe 2 O 3 ) [1,4,6] or in the form of complex compounds (EDTA + Fe 3+ ) [7].…”

Protective properties of PEO coatings modified by corrosion inhibitors on aluminum alloys

“…1) [19,22]. In these electrolytes, it is possible to create both protective/decorative coatings and coatings with catalytic [23] or magnetic properties [24] on aluminum and titanium alloys. These coatings find application in industrial practice [2].…”