Ferrite Toroid Core: Magnesium-Zinc Ferrite Fired at 1400 °C in Oxygen (Snoek)

Ferrite is a ceramic magnet: iron oxide combined with other metal oxides, carrying magnetic flux while hardly conducting electricity. Snoek at Philips (US 2,452,531, 1948) made this magnesium-zinc ferrite ring: magnesia, zinc oxide and iron oxide ground together, moulded with water into a ring and fired in oxygen at 1400 °C for 1 hour, then cooled slowly. His ring had an initial permeability of 525. The picture: our diagram.

高级

2 days

说明

Mix 26.5 : 26.5 : 47 mol

Mix pure magnesium oxide, zinc oxide and iron oxide in the molecular ratio 26.5 : 26.5 : 47. Ours, by weight: 9.95 g magnesium oxide, 20.10 g zinc oxide and 69.95 g ferric oxide per 100 g.

此步骤所需材料：

氧化镁9.95 克

氧化锌粉末20.1 克

氧化铁69.95 克

所需工具：

等臂天平

防尘口罩

Grind for 3 hours in an iron ball mill

Grind the mixture for 3 hours in a mill with iron balls.

所需工具：

铁球磨机

防尘口罩

Mould a ring at 4 tons per cm²

Mould a ring 3 cm across and 4 × 4 mm in section at 4 tons per square centimetre, with water as the plastifying and binding agent.

所需工具：

液压机

环形压制模

蒸馏水

Fire 1 hour at 1400 °C, cool at 3 °C a minute

Heat the ring in oxygen to 1400 °C for 1 hour (instead of 1300 °C), then cool it in oxygen at about 3 °C per minute. Snoek's ring had an initial permeability of 525.

所需工具：