Thermionic cathode comprising mixture of barium oxide, calcium oxide and samarium oxide

Claim 2

A CATHODE COMPRISING: A METALLIC BODY STRUCTURE OF A HIGH MELTING POINT METAL AND AN EMISSION SUPPORTED BY SAID BODY STRUCTURE, SAID EMISSION MATERIAL COMPRISING A MIXTURE OF BARIUM OXIDE, CALCIUM AND SAMARIUM OXIDE WITH THE AMOUNT OF SAMARIUM OXIDE PRESENT IN THE MIXTURE IN EXCESS OF ABOUT 12 MOL PERCENT.

Claim 3

A dispenser cathode comprising: a refractory metal body having an electron emission surface and a porous portion for migration of an emission material to said surface and emission material supported by and in contact with said body for migration through said porous portion to said surface, said emission material comprising a mixture of barium oxide, samarium oxide and a second alkaline earth metal oxide other than barium oxide with the amount of samarium oxide present in the mixture in excess of about 12 mol percent.

Claim 4

A dispenser cathode comprising: a refractory metal body having an electron emission surface and a porous portion for migration of an emission material to said surface and emission material supported by and in contact with said body for migration through said porous portion to said surface, said emission material comprising a mixture of barium oxide, samarium oxide and a second alkaline earth metal oxide other than barium oxide with the amount of samarium oxide present in the mixture in excess of about 12 mol percent.

Claim 5

The dispenser cathode in accordance with claim 2 wherein said second alkaline earth metal oxide is calcium oxide.

Claim 6

The dispenser cathode in accordance with claim 3 wherein said barium oxide, calcium oxide and samarium oxide are in the mole ratio of about 4:1:1, respectively.

Claim 7

The dispenser cathode in accordance with claim 3 wherein said barium oxide, calcium oxide and samarium oxide are in the mole ratio of about 5:3:2 respectively.

Claim 8

A dispenser cathode comprising: a porous high-density tungsten body with interconnecting pores communicating With an electron emission surface and an emission material located within said pores for migration through said pores to said surface, said emission material comprising a mixture of barium oxide, samarium oxide and a second alkaline earth metal oxide other than barium oxide with the amount of samarium oxide present in the mixture in excess of about 12 mol percent.

Claim 9

A dispenser cathode comprising: a porous high-density tungsten body with interconnecting pores communicating With an electron emission surface and an emission material located within said pores for migration through said pores to said surface, said emission material comprising a mixture of barium oxide, samarium oxide and a second alkaline earth metal oxide other than barium oxide with the amount of samarium oxide present in the mixture in excess of about 12 mol percent.

Claim 10

The dispenser cathode in accordance with claim 6 wherein said second alkaline earth metal oxide is calcium oxide.

Claim 11

The dispenser cathode in accordance with claim 7 wherein said barium oxide, calcium oxide and samarium oxide are in the mole ratio of about 4:1:1, respectively.