| 摘要 |
<p>A selenide layer is formed on an iron group e.g. nickel coated metal base plate by evaporating a layer of halogenated selenium up to 15m thick on to the coating while it is held at below 100 DEG C in vacuo, heating to react the selenium with the nickel layer, cooling, and reheating to convert the selenide to a conductive state. A further selenium layer is then evaporated in vacuo on to the converted selenide layer. The reaction conditions may be chosen so that not all of the nickel and selenium react, in which case the selenide and unconverted selenium are mechanically mixed to form a single uniform layer. Additives may be included in the further selenium layer by simultaneous evaporation. The individual heating and evaporating steps may be performed in the same vacuum by selectively switching on the heaters for the base plate and the appropriate evaporators without removing the plates. The coated base plate is used in the manufacture of a rectifier (see Group XXXVI].</p> |
