Understanding the Emission Mechanism of Barium Tungsten Cathodes

The emission mechanism of a barium tungsten cathode involves a process called thermionic emission. Here's how it works:

Barium Deposition: In a barium tungsten cathode, a thin layer of barium is deposited onto the surface of a tungsten substrate. This is typically achieved through a process called barium flashing, where the cathode is heated in a vacuum chamber containing a small amount of barium metal. The heat causes the barium to vaporize and deposit onto the tungsten surface.

Activation: Once the barium is deposited, the cathode is subjected to further heating, which activates the barium layer. During this activation process, some of the barium atoms lose electrons, becoming positively charged ions (Ba+), while others absorb electrons, becoming negatively charged (Ba-).

Electron Emission: When the cathode is heated to its operating temperature, typically several hundred to a few thousand degrees Celsius, the electrons in the tungsten lattice gain enough thermal energy to overcome the work function of the material. The work function is the minimum amount of energy required to liberate an electron from the surface of a material. In the case of barium tungsten cathodes, the presence of the barium layer lowers the work function of the tungsten substrate, making it easier for electrons to escape.

Emission Current: Once emitted from the surface of the cathode, the electrons form a cloud or beam, depending on the application. This emission of electrons constitutes the cathode's emission current, which can be controlled and manipulated to generate the desired electron beam characteristics.

In summary, the emission mechanism of a barium tungsten cathode relies on the thermionic emission process, facilitated by the presence of a barium layer on the tungsten substrate. This process enables the efficient generation and emission of electrons from the cathode surface, making it suitable for various applications such as electron microscopy, X-ray tubes, and electron beam welding.

Chinatungsten Online is a professional manufacturer of tungsten and molybdenum for nearly thirty years. We can supply barium tungsten cathodes in regular or customized drawings. Please free feel to contact us when you got the purchasing plans.

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Exploring the Applications of Barium Tungsten Cathodes in Electronic Devices

Barium tungsten cathodes play a pivotal role in a wide range of electronic devices and applications due to their exceptional electron emission properties. These cathodes, composed of a mixture of tungsten and barium compounds, are utilized in various fields where reliable and high-performance electron sources are required. 

Here are some primary applications of barium tungsten cathodes:

X-ray Tubes: One of the most common uses of BaW cathodes is in X-ray tubes used for medical imaging, industrial inspection, and scientific research. In X-ray tubes, the cathode emits electrons when heated, which collide with a target material, producing X-rays. They ensure efficient electron emission, resulting in high-quality X-ray images with excellent resolution and clarity.

Electron Microscopy: BaW cathodes find extensive use in electron microscopy, a technique used for imaging and analyzing the microstructure of materials at the nanometer scale. In electron microscopes, the cathode generates a focused electron beam that interacts with the specimen, allowing for detailed imaging and analysis of its morphology, composition, and properties.

Vacuum Electronics: BaW cathodes are essential components in vacuum electronic devices such as traveling-wave tubes (TWTs), klystrons, and magnetrons. These devices utilize electron beams generated by the cathode to amplify and manipulate microwave signals in various communication, radar, and defense systems. They enable stable and high-intensity electron emission, ensuring reliable operation of vacuum electronics in demanding environments.

Electron Beam Welding and Cutting: In electron beam welding and cutting uses, BaW cathodes are employed to generate high-energy electron beams used for joining or cutting metal components. The intense heat generated by the electron beam enables precise and efficient welding or cutting of materials, making it suitable for manufacturing aerospace components, automotive parts, and electronic devices.

Electron Beam Lithography: BaW cathodes are also utilized in electron beam lithography systems, which are used for semiconductor fabrication and nanofabrication processes. In electron beam lithography, the cathode generates a focused electron beam that is used to pattern or write circuit patterns onto a substrate with high precision and resolution.

Chinatungsten Online is a professional manufacturer of tungsten and molybdenum for nearly thirty years. We can supply barium tungsten cathodes in regular or customized drawings. Please free feel to contact us when you got the purchasing plans.

If you have any inquiry of barium tungsten cathode, please feel free to contact us:
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How Is Barium Tungsten Cathode Material Synthesized?

Barium tungsten cathodes are essential components in various electronic devices, including X-ray tubes and other vacuum electronics. These cathodes exhibit excellent electron emission properties, making them indispensable in applications requiring high-performance electron sources. However, the synthesis of barium tungsten cathode material is a crucial step in ensuring the functionality and efficiency of these devices.

The synthesis typically involves several intricate processes aimed at achieving the desired composition and structure. One common method for synthesizing this material is the powder metallurgy technique. In this method, finely powdered tungsten and barium compounds are mixed in precise proportions to form a homogeneous mixture. The mixture is then subjected to high temperatures in a controlled atmosphere, typically in a vacuum or inert gas environment. This process facilitates the chemical reaction between tungsten and barium, leading to the formation of barium tungstate (BaWO4) compounds.

Another approach to synthesizing the material involves chemical vapor deposition (CVD). In this method, volatile precursors containing tungsten and barium are introduced into a reaction chamber, where they undergo thermal decomposition at elevated temperatures. The resulting vapors react on the substrate surface to form thin films of barium tungsten compounds. CVD offers advantages such as precise control over film thickness and composition, making it suitable for producing uniform and high-quality cathode materials.

Additionally, sputtering techniques can be employed for depositing barium tungsten films onto substrates. In sputtering, high-energy ions bombard a target composed of tungsten and barium, causing atoms to be ejected from the target surface. These ejected atoms deposit onto the substrate, forming a thin film of barium tungsten material. Sputtering allows for the deposition of thin films with controlled thickness and excellent adhesion to the substrate, making it suitable for coating complex geometries.

Overall, the synthesis of barium tungsten cathode material involves sophisticated techniques aimed at achieving precise composition, structure, and morphology. The choice of synthesis method depends on factors such as desired film properties, substrate compatibility, and production scalability. With advancements in materials science and deposition technologies, the synthesis continues to evolve, enabling the development of high-performance electron emission devices for various applications.

Chinatungsten Online is a professional manufacturer of tungsten and molybdenum for nearly thirty years. We can supply barium tungsten cathodes in regular or customized drawings. Please free feel to contact us when you got the purchasing plans.

If you have any inquiry of barium tungsten cathode, please feel free to contact us:
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Exploring the Composition and Functionality of Barium Tungsten Cathodes

A barium tungsten cathode is a crucial component in various electronic devices, particularly in vacuum tubes and cathode ray tubes (CRTs). Its composition plays a significant role in determining its emission characteristics and overall performance.

Typically, a barium tungsten cathode consists of a substrate material, often made of tungsten due to its high melting point and mechanical stability. The tungsten substrate provides structural support and serves as the emitter surface for electron emission.

Embedded within onto the tungsten substrate is barium oxide (BaO) or barium strontium oxide (BaSrO). This layer acts as the source of electron emission when heated to high temperatures, a process known as thermionic emission. Barium is chosen for its low work function, which facilitates the release of electrons from the cathode surface.

Additionally, small amounts of other materials may be added to the cathode composition to enhance its performance or stability. These additives may include rare earth oxides or other electron-emitting compounds to improve emission efficiency or prolong cathode lifespan.

During operation, barium tungsten cathodes are heated to a high temperature, typically several hundred to over a thousand degrees Celsius, depending on the application. This heating causes the barium oxide to emit electrons into the surrounding vacuum, creating an electron cloud or beam.

The emitted electrons can then be accelerated and focused by electric and magnetic fields within the vacuum tube, allowing for various applications such as amplification, signal processing, or display generation in CRT monitors and television sets.

Overall, the composition of a barium tungsten cathode is carefully engineered to balance factors such as electron emission efficiency, stability, and longevity, making it a vital component in many electronic devices. Continued research and development in cathode materials and manufacturing processes aim to further improve performance and expand the range of functionality for these essential components.

Chinatungsten Online is a professional manufacturer of tungsten and molybdenum for nearly thirty years. We can supply barium tungsten cathodes in regular or customized drawings. Please free feel to contact us when you got the purchasing plans.

If you have any inquiry of barium tungsten cathodes, please feel free to contact us:

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E-Beam Tungsten Filament Price in Late April 2024

The latest price of φ0.8mm E-Beam tungsten filament is USD 2.20/PC, EXW XIAMEN, CHINA in the second half of April 2024. 

Tungsten filaments, also called cathodes or electron emitters or electron sources, are mainly made of high-quality tungsten. Of all pure metals, tungsten has the highest melting point (3422°C), the lowest vapor pressure at temperatures above 1650°C, and the highest tensile strength. Tungsten also has the lowest coefficient of thermal expansion of all pure metals. This combination of properties makes tungsten an ideal material.

Tungsten can be used in both thermionic electron guns and field-emission (CFE) electron guns. Electron beams come from filaments made of various materials. The most common is the tungsten hairpin gun, which is widely used in scanning electron microscopes, transmission electron microscopes, and microprobe systems. This filament is a tungsten ring that acts as a cathode. Apply voltage to the loop to heat it up. The anode, which is positive relative to the filament, forms a strong attraction to electrons. This causes electrons to be accelerated towards the anode. Some accelerate near the anode and down the column to the sample.

An electron gun works at a high temperature, which is required for thermionic emission. For this, a filament or the cathode should be of a material that has a high melting point in order for it to continuously emit electrons. Tungsten filament is folded with various shapes to help in focusing the electron beam.

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2% Ceriated Tungsten Electrode Price in Late April 2024

The latest price of φ1.6x150mm ceriated tungsten electrode is USD0.80/PC, EXW XIAMEN, CHINA in the second half of April 2024. 

Ceriated tungsten electrode (WC20) is alloyed with about 2% cerium oxide. It is a non-radioactive, refractory or non-consumable metal electrode material, which is the preferred substitute for thorium tungsten electrodes. Regular diameter of the electrode is between 0.5mm and 12.0mm, and the length is 150mm and 175mm.

The addition of this small percentage of cerium oxide increases the electron emission qualities of the electrode which gives them a better starting characteristic and a higher current carrying capacity with no spitting. With the increase of cerium oxide content, the ablation resistance and arc starting of ceriated tungsten electrode will increase; with the increase of use time, the welding performance will gradually decrease.

The electrode has excellent arc starting properties at low current, and can operate successfully with AC or DC electrode negative. If used on higher current applications, the cerium oxide April be concentrated to the excessively hot tip of the electrode. In addition, WC20 is also used in inert gas shielded arc welding, hydrogen atom welding, argon arc surfacing, pulse argon arc welding, plasma welding, plasma cutting, plasma spraying, plasma melting, etc. The welding materials can be carbon steel, stainless steel, silicon copper, copper, bronze, titanium and so on.

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