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Ferrite Toroid Core: Copper-Zinc Ferrite Milled 200 Hours, Fired at 1050 °C (Snoek)
Ferrite is a ceramic magnet: iron oxide combined with other metal oxides, carrying magnetic flux while hardly conducting electricity. In his first ferrite patent (US 2,452,529, 1948) Snoek at Philips ground the oxides very fine and fired rings in oxygen. This copper-zinc ferrite is milled about 200 hours, fired 2 hours at 1050 °C and held 12 hours at 600 °C; his core had an initial permeability of 200.
The picture: our diagram.
Advanced
2 weeks
Instructions
1
1
Mix 20 : 30 : 50 mol
Mix 20 : 30 : 50 mol
Mix pure copper oxide, zinc oxide and ferric oxide, 20 : 30 : 50 mol %. Ours, by weight: 13.24 g copper oxide, 20.32 g zinc oxide and 66.44 g ferric oxide per 100 g.
Materials for this step:
Copper Oxide13.24 g
Zinc Oxide Powder20.32 g
Ferric Oxide66.44 gTools needed:
Balance Scale
Dust Mask2
2
Grind about 200 hours in an iron ball mill
Grind about 200 hours in an iron ball mill
Grind the mixture for about 200 hours in an iron ball mill.
Tools needed:
Iron Ball Mill
Dust Mask3
3
Mould a ring at 4 tons per cm²
Mould a ring at 4 tons per cm²
Press the powder at 4 tons per square centimetre into a ring 3 cm across with a 4 × 4 mm section.
Tools needed:
Hydraulic Press
Ring Pressing Die4
4
Fire 2 hours at 1050 °C, hold 12 hours at 600 °C
Fire 2 hours at 1050 °C, hold 12 hours at 600 °C
Heat the ring for two hours at 1050 °C in a current of oxygen, cool at 5 °C a minute to 600 °C, hold it there 12 hours, then cool to room temperature, all in oxygen. Snoek's core: initial permeability 200.
Tools needed:
Tube Furnace
Oxygen
Pressure Gas Cylinder
Pyrometer
Crucible Tongs
Heat-Resistant GlovesMaterials
3- 13.24 gPlaceholder
- 20.32 gPlaceholder
- 66.44 gPlaceholder
Tools Required
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