Ceramic Disc Capacitors: Barium Titanate with Nickel Stannate, Pressed, Fired and Silvered (Coffeen, US 2,789,061)

Barium titanate with 3 mole % nickel stannate is calcined, pressed into small discs and fired hard. Silver is fired onto both faces and a lead soldered to each, giving ceramic disc capacitors of high capacity for their size. Result: discs 3/8 inch across and about 1/10 inch thick with a dielectric constant averaging 2380 and a dissipation factor of 0.58 %. Between 25 and 85 °C the dielectric constant rose at most 17 % and fell at most 7 %. Source: W. W. Coffeen (Metal & Thermit Corp.), US 2,789,061 (1957). Unknown: how the barium titanate, the nickel stannate and the tinned lead wire are made; the patent uses them ready-made. Picture: Wikimedia Commons.