An electrolytic method of preparation of iron-nickel-molybdenum alloy powders

Conclusions

• 1. A process has been developed for the electrolytic preparation of three-component Fe-Ni-Mo alloy powders of varying compositions (from 0 to 15% of molybdenum with any iron-to-nickel ratio).

• 2. An electrolyte has been chosen which is capable of fairly stable operation and contains no organic complexing agents; the electrolyte enables electrodeposition to be performed using several soluble and one insoluble anode, with independent regulation of the currents flowing through them.

• 3. A study was made of the effect of electrolysis parameters (D_C, temperature, pH, and solution composition) on current efficiency on the cathode and on the chemical composition and structure of the deposited alloy.

• 4. It was established that, under certain electrolysis conditions, when the electrodeposition of all the metals is controlled by diffusional kinetics, the resultant alloy composition is determined solely by the solution composition.

• 5. The optimum electrolysis conditions for the preparation of alloy powder of Permalloy composition are: an electrolyte containing (in mole/liter) 0.030 FeSO₄, 0.160 NiSO₄, 0.005–0.008 (NH₄)₂MoO₄, 0.15 (NH₄)₂SO₄, and 0.1–0.2 K₂SO₄+Na₂SO₄, D_c=2000–3000 A/m², temperature 20–25‡C, pH2.5–2.7,D ^Fe_a = 100–200 A/m², D ^Pb_a =1000–2000 A/m², D ^gauze_a =50–75 A/m², and ratio I ^Fe_a ∶ I ^Ni_a = 5∶ 27. The Mo(VI) concentration is maintained constant by periodic additions to the electrolyte of an (NH₄)₂M₀O₄ solution at pH 6–7.