Abstract An emissive electrode of the type utilized in fluorescent lamps and a method for making such an electrode. The electrode includes a fused cylindrical pellet and two metal leads, a portion of one of said leads extending within one end of said pellet and a portion of the other of said leads extending within the opposite end of the pellet. The pellet contains a fused mixture of electron emissive material and a metal having a high melting point and a low vapor pressure, and it has a bulk density gradient structure. The heat necessary to cause thermionic electron emission from said electrode is provided by current passing through the pellet structure separating said leads when a voltage is applied across said leads. The pellet is formed by mixing a powder of said metal with a powder of said electron emissive material, adhering said powder particles one to the other, and heating said mixed powder in a mold until an exothermic reaction occurs.
An emissive electrode, according to claim 1, wherein said body is cylindrical in shape and said leads extend from opposite ends thereof.
Claim 2
Dependent Claim
14 words
An emissive electrode, according to claim 1, wherein said metal comprises a refractory metal.
Claim 3
Dependent Claim
15 words
An emissive electrode, according to claim 1, wherein said metal comprises a transitional element metal.
Claim 4
Dependent Claim
17 words
An emissive electrode, according to claim 1, wherein said electron emissive material comprises an alkaline earth compound.
Claim 5
Dependent Claim
16 words
An emissive electrode, according to claim 1, wherein said electron emissive material comprises an alkali compound.
Claim 6
Dependent Claim
50 words
An emissive electrode, according to claim 1, wherein said metal comprises tantalum and said electron emissive material comprises barium peroxide, said tantalum being between 60 percent and 70 percent by weight of said mixture and said barium peroxide being between 30 percent and 40 percent by weight of said mixture.