16 results about "Tungsten cathode" patented technology

The invention relates to the technical field of rare earth metal electrolysis cathode protection coatings, in particular to a high-temperature-corrosion-resistant yttrium-stabilized zirconia gradient coating on the surface of a tungsten cathode. A metallurgically bonded strong bonding bottom layer is constructed on a tungsten substrate through surface pretreatment and reactive sintering, then an atmosphere plasma technology is adopted to spray a creep-resistant gradient layer with continuous components to buffer thermal stress, and finally a sol-gel technology is utilized to construct an extremely compact corrosion-resistant surface layer in a superposition mode. The high-temperature-corrosion-resistant yttrium-stabilized zirconia gradient coating is constructed through a multi-scale and multi-mechanism synergistic effect, the problems that a tungsten cathode coating is insufficient in binding force and poor in thermal shock resistance are fundamentally solved, molten salt permeation can be blocked, and the service life of a tungsten cathode in a severe environment is remarkably prolonged.

The invention belongs to the technical field of material preparation and new energy, and particularly relates to a method for preparing nano cathode composite powder by spray drying, which comprises the following steps: (1) pretreating nano tungsten powder; (2) preparing mixed slurry; (3) ultrasonic atomization; (4) spray drying of atomized liquid drops; and (5) synchronously reducing and calcining to obtain the nano cathode composite powder prepared by spray drying. The prepared nano cathode composite powder has a uniformly dispersed multi-component structure and optimized phase composition, and the emission current density of a barium-tungsten cathode in practical application can be remarkably improved.

The invention discloses a gradient preparation method of a compact barrier type rare earth ceramic coating, and belongs to the technical field of high-temperature protective coatings. The preparation method comprises the following steps: pretreating a tungsten electrode substrate; sequentially preparing a sensor layer integrated with a distributed optical fiber sensor, a gradient transition layer which is realized by adopting a four-channel synchronous powder feeding technology and has continuous and gradual components, and a self-adaptive layer which is prepared by adopting a laser-induced in-situ synthesis technology and contains high-entropy rare earth zirconate and an intelligent additive; the self-healing layer contains a triple temperature triggering microcapsule system; and finally, post-processing and function activation are carried out. The prepared coating forms an intelligent response type gradient composite structure from inside to outside, has excellent interface bonding strength, thermal shock resistance and high-temperature chemical stability and has damage self-healing and service state real-time monitoring functions, and the service life of the tungsten cathode under the severe working condition is remarkably prolonged.

The invention provides a composite film M-type hot cathode and a preparation method thereof. The composite film layer M-type hot cathode comprises a barium tungsten cathode substrate, a Re3W alloy phase barrier layer and a noble metal surface layer, and the Re3W alloy phase barrier layer is formed between the barium-tungsten cathode substrate and the noble metal surface layer. The composite film layer M-type thermionic cathode can effectively prevent alloying between the tungsten substrate and the precious metal film layer, so that the emission capability of the cathode is improved, and the service life of the cathode is prolonged.

The application discloses a chemical vapor deposition hafnium carbide coating for repairing a tungsten cathode, and belongs to the technical field of high-temperature electrochemistry and surface engineering. The coating comprises a tungsten carbide gradient transition layer, discrete distributed hexagonal boron nitride nano-islands and a hafnium carbide deposition layer in sequence. The application adopts h-BN nano-islands as a template to induce the growth of HfC nano-pillars, forms strong nano-mechanical interlocking, combines the metallurgical bonding of the WC gradient layer, and endows the coating with super-strong bonding force and thermal shock resistance; the use of nitrogen-free hafnium source ensures the low nitrogen intrinsic high purity of the HfC coating, thereby obtaining excellent high-temperature molten salt corrosion resistance; the h-BN island design with extremely low coverage rate ensures mechanical enhancement while maximizing the maintenance of the low interface contact resistance of the coating system. The method has a wide process window and excellent performance, and can significantly prolong the service life of the tungsten cathode under extreme working conditions.

The invention relates to the technical field of rare earth metal electrolysis cathode protection coatings, in particular to an in-situ generated rare earth oxide diffusion barrier layer on the surface of a tungsten cathode. According to the method, fused salt electrodeposition and sol chemical deposition are combined, and a composite diffusion barrier layer of an yttrium tungstate binding layer / yttrium oxyfluoride barrier layer is constructed on the surface of a tungsten cathode in situ; the method comprises the following steps: firstly, enabling sodium tungstate to react with yttrium fluoride in fused salt through electro-deposition, and generating a compact and firmly combined yttrium tungstate layer on a tungsten substrate in situ; and then a compact surface layer of multiple yttrium oxyfluoride layers is constructed on the surface of the tungsten cathode by adopting a sol-gel method, strong interface bonding is realized by utilizing an in-situ reaction, surface hole sealing is realized by utilizing the densification characteristic of yttrium oxyfluoride, finally, a composite protection structure is formed, and the high-temperature oxidation resistance and molten salt corrosion resistance of the tungsten cathode are remarkably improved.

The X-ray generating device with switchable focus of the present invention includes a high-voltage power supply and an X-ray tube. The X-ray tube is disposed at one end of the high-voltage power supply and includes a cathode assembly, an anode assembly, an electron beam focusing assembly, a housing assembly, and a vacuum assembly. The cathode assembly includes a replaceable cathode unit, which is a lanthanum hexaboride cathode or a zirconium oxide tungsten cathode. By setting the replaceable cathode unit to a lanthanum hexaboride cathode or a zirconium oxide tungsten cathode, free switching between microfocus mode and nanofocus mode is achieved, enabling high resolution and high power output on the same device, and simultaneously meeting the high-precision inspection requirements of chip packaging and the high-power inspection requirements of circuit boards, batteries, etc.

This invention discloses a chemical vapor deposition (CVD) hafnium carbide (HfC) coating for repairing tungsten cathodes, belonging to the field of high-temperature electrochemistry and surface engineering technology. The coating comprises a tungsten carbide gradient transition layer, discretely distributed hexagonal boron nitride (HfC) nanoislands, and a hafnium carbide deposition layer. This invention uses HfC nanoislands as templates to induce the growth of HfC nanopillars, forming strong nanomechanical interlocking. Combined with the metallurgical bonding of the WC gradient layer, this imparts the coating with superior adhesion and thermal shock resistance. The use of a nitrogen-free hafnium source ensures the low-nitrogen intrinsic high purity of the HfC coating, thereby achieving excellent resistance to high-temperature molten salt corrosion. The extremely low coverage hfC island design ensures mechanical reinforcement while maximizing the maintenance of low interfacial contact resistance in the coating system. This method has a wide process window, excellent performance, and can significantly extend the service life of tungsten cathodes under extreme operating conditions.

This invention belongs to the field of materials preparation and new energy technology, specifically a method for preparing nano-cathode composite powder by spray drying, comprising the following steps: step (1) pretreatment of nano-tungsten powder; step (2) preparation of mixed slurry; step (3) ultrasonic atomization; step (4) spray drying of atomized droplets; and step (5) simultaneous reduction calcination to obtain nano-cathode composite powder prepared by spray drying. The nano-cathode composite powder prepared by this invention has a uniformly dispersed multi-component structure and optimized phase composition, which can significantly improve the emission current density of barium tungsten cathodes in practical applications.

The invention belongs to the technical field of electric light source manufacturing, and discloses a thorium-tungsten cathode for a short-arc discharge lamp and a preparation method and application of the thorium-tungsten cathode. The preparation method of the thorium-tungsten cathode for the short arc discharge lamp comprises the following steps: S1, coating the surface of a thorium-tungsten cathode substrate with a heat treatment solution to obtain the thorium-tungsten cathode comprising a carbon source coating; and S2, carrying out segmented heat treatment on the thorium-tungsten cathode comprising the carbon source coating, and cooling to obtain the thorium-tungsten cathode for the short arc discharge lamp. According to the preparation method of the thorium-tungsten cathode for the short-arc discharge lamp, through specific material and process design, the surface components and the structure of the thorium-tungsten cathode are synergistically optimized on the microscopic level, the emission capability, the thermal erosion resistance and the long-term structural stability of the thorium-tungsten cathode are enhanced, and the comprehensive improvement of the short-arc discharge light output performance is jointly realized.

The invention belongs to the field of microwave vacuum electronic technology and refractory metal powder metallurgy, and particularly relates to a tungsten-scandium mixed matrix for a high-power hot cathode and a preparation method and application of the tungsten-scandium mixed matrix. The porosity of through holes of the tungsten-scandium mixed matrix is 18-30%, the average aperture is 0.3-2.0 microns, the scandium oxide content is 1-10 wt%, the percentage of closed area is smaller than or equal to 1%, and the specific surface area of the tungsten-scandium mixed matrix is smaller than or equal to 1%. And the grain size of the scandium oxide in the mixed matrix is not more than 1 mu m after sintering. The preparation method comprises the steps of tungsten powder grading, grinding and coating, vacuum drying, reduction purification, sieving, blending, cold isostatic pressing forming, hydrogen pre-sintering, precision machining, hydrogen high-temperature sintering and the like. In addition, the tungsten-scandium mixed substrate prepared by the method can be applied to scenes such as high-power terahertz devices and the like, and can replace a conventional M-type impregnated barium-tungsten cathode.

The invention relates to the technical field of laser cladding, in particular to a laser cladding tungsten-based composite material in-situ repairing method for tungsten cathode defects. The invention discloses a laser cladding tungsten-based composite material in-situ repairing method for tungsten cathode defects. The method comprises the following steps: firstly, pretreating a defect part to thoroughly remove a corrosion layer; then laser cladding is carried out in two steps, wherein the size is recovered through a recovery layer of the palladium-titanium carbide reinforced tungsten-based composite material, and the obdurability and compactness are guaranteed; and then the functional surface layer of the yttrium-zirconium doped tungsten alloy is used as a functional surface layer to improve the high-temperature oxidation resistance, metallurgical bonding of the repairing layer and the base body is achieved through the method, and the repairing body has the characteristics of high temperature resistance and high strength.

The invention relates to a heat treatment method of a lanthanum-tungsten hollow cathode, and belongs to the technical field of tungsten alloy heat treatment, the lanthanum-tungsten hollow cathode is firstly pretreated and cleaned and then placed in a protective atmosphere to be sequentially subjected to first-stage heat treatment and second-stage heat treatment, in the first-stage heat treatment, the temperature is increased to 15-35 DEG C at the heating rate of 1-10 DEG C / s, heat preservation is conducted for 15-30 min, and then the lanthanum-tungsten hollow cathode is cooled to the room temperature; in the second-stage heat treatment, the temperature is increased to 200-800 DEG C at the heating rate of 1-10 DEG C / s, heat preservation is conducted for 1-24 h, and finally air cooling is conducted to the room temperature Through heat treatment, the grain surface orientation in the lanthanum-tungsten cathode is changed and tends to be consistent, so that the plasma ablation resistance of the lanthanum-tungsten cathode is improved, and the lanthanum-tungsten cathode has huge market requirements and wide application prospects in the aerospace field of a magnetic plasma power thruster (MPDT) and the like.

The application relates to a method for preparing porous tungsten at low temperature based on reaction sintering, and relates to the technical field of barium-tungsten cathode material preparation. By introducing aluminum as a sintering additive and a binder, a self-sustaining high-temperature sintering process can be realized, the reaction is self-sustaining, energy consumption is low, reactants are fully mixed, and the speed is fast. Moreover, the generated Al2O3 is a component of the tungsten cathode, and the working stability of the cathode is improved, so that CaO required by the cathode can be added on the basis of reaction heat release, the reaction heat release of aluminum and tungsten oxide promotes sintering, and the required CaO-Al2O3 composite salt is generated. In the sintering process, Al forms a local liquid phase, promotes the interaction between particles, and thus a tungsten material with high density is obtained at a lower temperature, the generated Al2O3 is compounded with CaO at high temperature, and the sintering and salt immersion processes are simultaneously performed, so that the cost of tungsten cathode preparation is greatly reduced.

Disclosed is an all-solid-state battery using a non-carbon-based tungsten oxide cathode additive having high conductivity and high safety. The cathode additive according to an embodiment comprises a tungsten oxide having an oxygen vacancy, and the tungsten oxide can replace a carbon-based conductive material in a cathode composite compound for an all-solid-state battery.

The invention discloses high-purity spherical tungsten-based composite powder for plasma spraying and a preparation method and application of the high-purity spherical tungsten-based composite powder, and belongs to the technical field of metal composite materials. According to the composite powder, a nano-porous rare earth modified zirconium oxide corrosion-resistant phase is prepared through a sol-gel-carbon template method, a core-shell-internal dispersion structure is formed through the cooperation of pre-alloying and a secondary atomization technology, and then vacuum annealing optimization is conducted; the composite powder takes tungsten as a core, a WOx / rare earth oxide transition layer of 5-20 nm is contained on the surface, the particle size is 15-45 microns, and the sphericity degree is larger than or equal to 0.95. In order to overcome the defects that existing tungsten powder is single in component, low in sphericity degree, poor in molten salt corrosion resistance and weak in interface bonding, the corrosion resistance and bonding strength of a coating are remarkably improved through double corrosion-resistant protection and interface regulation and control, the service life of a rare earth molten salt electrolysis tungsten cathode is prolonged by 50% or above, and the plasma spraying technology is perfectly adapted.