Impregnated Yttric or Gadolinium-Containing Barium-Aluminum-Scandate Cathodes and Their Fabrication Methods

An impregnated rare earth-containing Barium-aluminum-scandate cathode, comprising:

• a first rare earth oxide doped tungsten matrix;
• and
• an impregnated active substance that comprises scandium oxide (Sc2O3),
• a second rare earth oxide, and Barium-calcium-aluminate;
• wherein the first and the second rare earth oxides are yttrium oxide(Y2O3) or gadolinium oxide (Gd2O3);

A method for making an impregnated rare earth-containing Barium-aluminum-scandate cathode with a rare earth oxide doped tungsten matrix, comprising:

• mixing a rare earth oxide with a tungsten powder;
• pressing the mixed powders into pellets under a pressure between 1.5 t/cm2 to 4 t/cm2;
• sintering the pellet under hydrogen at a temperature between 1500° C. and 1600° C. for 10 to 20 minutes to obtain a matrix;
• dissolving a raw material comprising scandium nitrate, barium nitrate, calcium nitrate, aluminum nitrate, and rare earth nitrate in de-ionized water to obtain a raw material solution;
• titrating an excess amount of aqueous ammonium carbonate solution into the raw material solution until all cations are precipitated out;
• leaching the precipitated solid;
• drying the solid;
• calcining the dried solid under air/oxygen at a temperature between 650° C. and 950° C. for 2 to 5 hours;
• reacting the calcined solid under dry hydrogen at a temperature between 1500° C. and 1600° C. for 10 to 30 minutes to obtain an impregnated active substance;
• and
• impregnating the active substance into the matrix under hydrogen at a temperature between 1600° C. and 1650° C. for 1 to 3 minutes.

A method for making a rare earth oxide doped tungsten matrix, comprising:

• mixing a rare earth oxide power and a tungsten powder;
• pressing the mixed powders into pellets;
• and
• sintering the pellet to obtain a matrix.

A method for making an impregnated active substance, comprising:

• dissolving the raw materials comprising scandium nitrate, barium nitrate calcium nitrate, aluminum nitrate, and rare earth nitrate in de-ionized water to obtain a raw material solution;
• titrating an excess amount of aqueous ammonium carbonate solution into the raw material solution until all cations are precipitated out;
• leaching the precipitated solid from the solution;
• drying the solid;
• calcining the dried solid;
• and
• reacting the calcined solid under dry hydrogen.