Lead Ferrite Disc Magnet: 0.3 mol PbO2 to 1.5 mol Iron Oxide, Two-Stage Presinter (Went, Philips 1956, Ex. 16)

A ceramic magnet with lead in place of barium: 0.3 mol lead dioxide to 1.5 mol iron oxide, milled, pressed into pastilles, presintered at 700 °C and 900 °C, ground in a mortar, pressed and passed through a 1150 °C furnace in 3 to 5 minutes. Went's rod held 1,420 gauss with a coercive force of 1,685 oersted. Lead compounds are poisonous. Source: J. J. Went, G. W. van Oosterhout and E. W. Gorter (Philips), US 2,762,777 (1956), Example 16. They sintered rods; discs and the magnetising are ours. Picture: ferrite magnets, Omegatron, Wikimedia Commons, CC BY-SA 3.0.