Barium-Calcium Ferrite Disc Magnet: Equal Barium and Calcium, Sintered at 1280 °C (Went, Philips 1956, Ex. 22)

A ceramic magnet with equal parts barium and calcium: 0.3 mol barium carbonate, 0.3 mol calcium carbonate and 3.1 mol iron oxide, milled 15 hours, pressed and passed through a 1280 °C furnace in 10 minutes, with no presintering. Went's rod held 1,595 gauss with a coercive force of 1,890 oersted. Source: J. J. Went, G. W. van Oosterhout and E. W. Gorter (Philips), US 2,762,777 (1956), Example 22. They sintered rods; discs and the magnetising are ours. Picture: ferrite magnets, Omegatron, Wikimedia Commons, CC BY-SA 3.0.