Accession Number : AD0292257

Title :   DEVELOPMENT AND TESTING OF TUNGSTEN EMITTERS FOR ION PROPULSION SYSTEMS

Corporate Author : TAPCO DIV THOMPSON RAMO WOOLDRIDGE INC CLEVELAND OHIO

Personal Author(s) : GERKEN,J.M. ; HILTZ,R.H. ; LALLY,F.J.

Report Date : OCT 1962

Pagination or Media Count : 1

Abstract : A process is presented for the production of porous tungsten emitter discs with a pore spectrum of 0.7 to 0.9 microns and a mean pore diameter of 0.8 microns. Studies of joining the emitter discs to refractory metal plenum chamber by electron beam welding were condcted. Work was performed on both tungsten and columbium plenum chambers and in both cases embrittlement was a serious problem. Although difficulties were encountered in successfully welding round emitters into the plenum chamber, sufficient assemblies were prepared for testing. Assemblies successfully withstood 100 hour exposure at 2500 F in a cesium atmosphere. An initial ion efficiency of 98.4% was obtained but due to poisoning the ion efficiency decreased with increasing time at temperature. (Author)

Descriptors :   *ELECTRIC PROPULSION, *MANUFACTURING, *TUNGSTEN, CESIUM, ELECTRON BEAMS, NIOBIUM, POROUS METALS, SECONDARY EMISSION, WELDING

Distribution Statement : APPROVED FOR PUBLIC RELEASE