Method of manufacturing a dispenser cathode; dispenser cathode manufactured according to the method, and device incorporating such a cathode
AssigneeU.S. Philips Corporation
InventorsJohannes van Esdonk, Jacobus Stoffels
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Abstract
A method of producing a dispenser cathode provided with a top layer, in which a main body of tungsten powder is pressed to a moulding at a first pressing pressure which is sufficient to preserve the shape of the moulding when the first pressure is removed but is not sufficient to break the powder grains to a significant extent. This moulding is thereafter provided with a top layer of a second power, whereafter the overall assembly is compressed in a second pressing operation at a second, higher pressing pressure, at which pressure the powder grains are broken to a significant extent.
Claims11
A method of manufacturing a dispenser cathode having a curved emitting surface comprising a porous cathode body predominantly comprising a refractory metal or refractory metal alloy and having a top layer which differs from the rest of the cathode body, the method comprising pressing the powder to form a body, characterized in that in a first step a first powder is pressed in a first pressing operation at a first pressure to form a coherent moulding, the first pressure being insufficient to break powder grains to a significant extent, the moulding thereafter in a second step is coated with a top layer of a second powder, whereafter in a third step the whole assembly is compressed at a second, higher pressure, whereby the powder grains are broken to a significant extent.
Dependencies are inferred from the claim text.