| 摘要 |
<p>Thermal cathode, esp for electron tubes, contains (I) a carrier contg. >=1 high melting pt. metal, (II) lathanum oxide as active substance, and (III) a carbon-contg. reducing agent areacting with (II) under the thermal operating conditions. High emission current densities and specific electron yields at low operating temps. with good ductility are obtd. (I) pref. consists of Mo or W; III pref. consists of a carbide of I, or elementary carbon. The outer zone of the cathode pref. contains a higher concn. of III than its interior. The cathode pref. contains a substance inhibiting the grain growth to (I) and/or (III), esp. a cpd of K, Na, Al or Si.</p> |
