Electrode for pulse high-power electrovacuum devices

Claim 2

An article of manufacture comprising an electrode and a multi-layer coating on said electrode for protecting the same against effects of erosion and gas emission, caused by electron bombardment, in an electro-vacuum device operating on pulSe duty, said coating comprising an outer layer of a material possessing a high permissible temperature of heating in vacuum for allowing said outer layer to withstand a pulse thermal load several times as high as the maximum load that would be permissible for an electrode having no protective coating, a transitional layer located between the outer layer and the electrode to ensure dependable bonding and effective thermal contact between the outer layer and the electrode, the transitional layer possessing thermophysical properties gradually varying in the range of values between such properties of the electrode and such properties of the outer layer, said protective coating being comparatively thin so that its thermal resistance to a constant thermal flow is minimal in comparison with the thermal resistance of an electrode having no coating, the thickness of the protective coating being not more than that of the thermal skinlayer, but sufficient to provide a smoothing effect on the thermal pulses and to transform them into a constant thermal power at a lower temperature at which such power can be dealt with the electrode with a thermal conductivity sufficiently high to be able to transfer the mean thermal power.

Claim 3

An article as claimed in claim 1, wherein said outer layer consists of at least one refractory metal selected from the group consisting of tungsten, tantalum, niobium, rhenium, rhodium, molybdenum, and said transitional layer consists of at least one metal selected from the group consisting of gold, nickel, iron, titanium, and platinum, the thickness of the protective coating being not more than that of the thermal skin-layer.

Claim 4

An article as claimed in claim 1, wherein said outer layer consists of at least one refractory metal selected from the group consisting of tungsten, tantalum, niobium, rhenium, rhodium and molybdenum and having a high permissible temperature of heating in a vacuum such as to allow said outer layer to withstand a pulse thermal load that would be permissible for a copper electrode having no protective coating, said electrode being of copper, said transitional layer consisting of a surface layer of copper on the copper electrode and ions of the refractory metal of which the outer layer consists.

Claim 5

A multilayer coating for protecting an electrode against effects or erosion and gas emission caused by electron bombardment in an electrovacuum device operating on continuous duty, said coating comprising an outer layer of a material having a high permissible temperature of heating in vacuum to allow said outer layer to withstand a continuous thermal load several times as high as the maximum load that would be permissible for an electrode having no protective coating, and a transitional layer located between said outer layer and the electrode to insure dependable bonding and effective thermal contact between the outer layer and the electrode, the transitional layer having thermo-physical properties gradually varying in the range of values between the same properties of the electrode and the same properties of the outer layer, said protective coating being comparatively thin so that its thermal resistance to a constant thermal flow is minimal in comparison with the thermal resistance of an electrode having a thermal conductivity sufficiently high to be able to transfer a considerable continuous thermal power, but sufficiently thick and solid to be free of pores or cracks and to be able to prevent emission of metal vapors and gases from the working surface of the electrode at constant temperatures several times as high as the maximum temperature permissible for heating in a vacuum of an electrode having no protective coating, the thickness of the said coating not exceeding ten microns.

Claim 6

A multilayer coating for protecting an electrode against effects or erosion and gas emission caused by electron bombardment in an electrovacuum device operating on continuous duty, said coating comprising an outer layer of a material having a high permissible temperature of heating in vacuum to allow said outer layer to withstand a continuous thermal load several times as high as the maximum load that would be permissible for an electrode having no protective coating, and a transitional layer located between said outer layer and the electrode to insure dependable bonding and effective thermal contact between the outer layer and the electrode, the transitional layer having thermo-physical properties gradually varying in the range of values between the same properties of the electrode and the same properties of the outer layer, said protective coating being comparatively thin so that its thermal resistance to a constant thermal flow is minimal in comparison with the thermal resistance of an electrode having a thermal conductivity sufficiently high to be able to transfer a considerable continuous thermal power, but sufficiently thick and solid to be free of pores or cracks and to be able to prevent emission of metal vapors and gases from the working surface of the electrode at constant temperatures several times as high as the maximum temperature permissible for heating in a vacuum of an electrode having no protective coating, the thickness of the said coating not exceeding ten microns.

Claim 7

A multilayer coating as claimed in claim 4, wherein the outer layer consists of at least one refractory metal selected from the group consisting of tungsten, tantalum, niobium, rhenium, rhodium and molybdenum, said transitional layer comprises at least one mEtal selected from the group consisting of gold, nickel, iron, titanium and platinum, the thickness of the said coating not exceeding 10 microns.

Claim 8

A multilayer coating as claimed in claim 4, wherein said outer layer consists of at least one refractory metal selected from the group consisting of tungsten, tantalum, niobium, rhenium, rhodium and molybdenum and having a high permissible temperature of heating in a vacuum such as to allow said outer layer to withstand a continuous thermal load that would be permissible for a copper electrode having no protective coating, said electrode being of copper, said transitional layer comprising a surface layer of copper on the electrode and ions of the refractory metal of which the outer layer consists.