| Abstract: | A method is described whereby nonplastic materials such as refractory oxides are given a temporary plasticity, sufficient for extrusion. The organic plastic gel used consists of flour or starch paste with ammonia as an electrolyte. A short detailed account is given of the manufacture of twin-hole insulators made of MgO 98% and talc 2% for radio 227 vacuum tubes, with supplemental experimental results on other materials. The refractory oxides Al2O3, BeO, ZrO2, MgO, and ThO2 are compared from the standpoint of their physical properties and their ability to act as insulators in contact with hot tungsten filaments. Examples are given of the use of such extruded oxide insulators for hot filament supports. |
