Metal Oxide Varistor: Zinc Oxide with Bismuth, Manganese and Boric Oxides, 1350 °C (Masuyama 1972, Ex. 3)

Masuyama, Matsuoka and Nishi found that adding two more oxides to zinc oxide and bismuth oxide gives excellent non-linear properties. This is their Example 3 with manganese dioxide and boric oxide: 98.5 % zinc oxide and 0.5 % each of bismuth oxide, manganese dioxide and boric oxide by moles, sintered at 1350 °C. The disc measured a C-value of 101 at 1 mA and a nonlinearity exponent n of 22.2. Source: T. Masuyama, M. Matsuoka and T. Nishi (Matsushita), US 3,663,458 (1972), Example 3. Unknown: how the aluminium is sprayed on and what the silver paint is. The 10 g batch is our arithmetic. Picture: the patent's drawing.