| abstract |
A thermionic converter is provided in which a protective silicon carbide shell is provided around the refractory metal emitter of the converter to shield it from the hot gases of a fossil fuel heat source and prevent oxidation of the emitter. The silicon carbide shell is spaced from the emitter so that stresses are not set up which would cause crackling or breaking of the shell. Heat transfer between the protective shell and the emitter is effected by means of a metal conductor which is liquid at the operating temperature of the converter. To obtain a long-life unit the silicon carbide shell is formed by uniformly depositing silicon carbide on the outer surface of a rotating, heated graphite mandrel. |