The Use of Single Crystals of Tungsten as High-Temperature Heaters of Long Cathodes

The first results of testing of single crystals of tungsten as a material for heaters of long cathodes in powerful electric vacuum devices showed that during the operation of the heaters under conditions of thermal cyclings their brittle rupture occurs. It has been established that cyclic temperature load gives rise to thermal fatigue of the heaters made from single crystals of tungsten; however, prolonged vacuum annealing makes it possible to delay the onset of thermal fatigue of the heaters and to ensure the necessary life of a cathode even under vibration and shock loads. (Author) Edited machine trans. of mono. Monokristally Tugoplavkikh i Redkikh Metallov (Single Crystals of Refractory and Rare Metals, Moscow, 1969 p172-179, by Francis T. Russell.