Target for barium-scandate dispenser cathode
AssigneeKoninklijke Philips N.V.
InventorsGeorg Friedrich Gaertner, Wilhelmus Cornelis Keur
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Abstract
The invention relates to the field of production of barium-scandate dispenser cathodes or other barium-scan-date materials. A target (66) containing a mixture of BaO, CaO, Al2O3 and SC2O3 tends to be more stable, the higher the scandia (scandium oxide) content is. However, an increased scandia content results in a reduced emission capability. A destabilizing effect of BaO and CaO reactions is counteracted by the more inert SC2O3 and also AI2O3 components, as not only an increased scandia content stabilizes the material but also an increased alumina (aluminum oxide) content improves the stability.
Claims13
A target material for physical thin film deposition used in a production of barium-scandate dispenser cathodes or other barium-scandate materials,
- wherein the target material comprises a mixture of barium oxide BaO, calcium oxide CaO, aluminium oxide Al2O3 and scandium oxide Sc2O3,
- wherein the molar ratio of BaO:CaO:Al2O3:Sc2O3 is b:c:x:y with 2≦b≦5, 1≦c≦3, 2≦x+y≦b+c and 0.1≦y≦1.
A use of a target material in a production of a barium-scandate dispenser cathode or other barium-scandate materials,
- wherein the target material comprises or consists of a mixture of barium oxide BaO, calcium oxide CaO, aluminium oxide Al2O3 and scandium oxide Sc2O3,
- wherein the molar ratio of BaO:CaO:Al2O3:Sc2O3 is b:c:x:y with 2≦b≦5, 1≦c≦3, 2≦x+y≦b+c and 0.1≦y≦1.
A method of producing a barium scandate dispenser cathode, comprising:
- providing a porous metal body having a surface and being impregnated with one or more compounds for dispensing at least barium and scandium to the surface,
- providing an intermediate layer consisting of or comprising BaO, CaO, Al2O3, and Sc2O3 by means of physical thin film deposition on the porous metal body, and
- providing an outer metal layer,
- wherein for the physical thin film deposition of the intermediate layer a target material is used comprising or consisting of a mixture of barium oxide BaO, calcium oxide CaO, aluminium oxide Al2O3 and scandium oxide Sc2O3,
- wherein the molar ratio of BaO:CaO:Al2O3:Sc2O3 is b:c:x:y with 2≦b≦5, 1≦c≦3, 2≦x+y≦b+c and 0.1≦y≦1.
A method for producing a target for physical thin film deposition for use in a production of barium-scandate dispenser cathodes or other barium-scandate materials,
- providing (12, 14, 14′, 16) a mixture of barium oxide BaO, calcium oxide CaO, aluminium oxide Al2O3 and scandium oxide Sc2O3,
- sintering melting the mixture to form the target,
- wherein the molar ratio of BaO:CaO:Al2O3:Sc2O3 in the target is b:c:x:y with 2≦b≦5, 1≦c≦3, 2≦x+y≦b+c and 0.1≦y≦1.
Dependencies are inferred from the claim text.