Barium Ferrite Disc Magnet: 1 mol BaCO3 to 2.5 mol Iron Oxide, 1310 °C (Went, Philips 1956, Ex. 1)

Went's first barium ferrite: 1 mol barium carbonate to 2.5 mol iron oxide, milled 13.5 hours, bound, formed and passed through a 1310 °C furnace in 20 minutes. His rod held 1,200 gauss with a coercive force of 1,940 oersted. Source: J. J. Went, G. W. van Oosterhout and E. W. Gorter (Philips), US 2,762,777 (1956), Example 1. They sintered rods; discs and the magnetising are ours. Picture: ferrite magnets, Omegatron, Wikimedia Commons, CC BY-SA 3.0.