Method of manufacturing a thermionic cathode structure
AssigneeThorn Microwave Devices Limited
InventorMichael S. Frost
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Abstract
A method of manufacturing a thermionic cathode structure comprises the steps of: (1) forming a mixture of (a) tungsten powder, (b) at least one of the group comprising alumina or zirconia or yttrium oxide powder, (c) alkaline earth metal carbonate powder, and (d) a binder, (2) pressing the mixture isostatically causing the mixture to adhere to form an electrically insulating body, (3) sintering the body in a dry hydrogen ambient thereby reducing the carbonate, and (4) coating the surface of the body or a portion of the surface with a poly-crystalline metal layer.
Claims2
A method of manufacturing a thermionic cathode structure comprising the steps of:
- (a) forming a mixture comprising:
- (i) between 5 wt % and 50 wt % tungsten powder,
- (ii) at least one member selected from the group consisting of alumina, zirconia and yttrium oxide powder,
- (iii) alkaline earth metal carbonate powder, and
- (iv) a binder,
- (b) pressing the mixture, thereby causing the mixture to adhere to form a body, and
- (c) sintering the body in a reducing ambient thereby decomposing the said carbonate powder, characterized in that the sintered body is an electrical insulator;
- and the method further comprises the step of
- (d) providing a polycrystalline metal layer on a surface of the body.
Dependencies are inferred from the claim text.