What Factors Influence the Longevity of Barium Tungsten Cathodes?

Barium tungsten cathodes are critical components in electron emission devices. The longevity of these cathodes directly impacts the efficiency and operational lifespan of the devices they are used in. 

Several factors influence the durability and performance of barium tungsten cathodes, as detailed below.

Operating Temperature

Operating temperature is one of the most significant factors affecting the lifespan of BaW cathodes. These cathodes rely on thermionic emission, which requires elevated temperatures. However, prolonged exposure to excessively high temperatures can accelerate barium depletion and cause structural degradation of the tungsten matrix. Maintaining an optimal operating temperature is crucial to maximizing longevity.

Surface Contamination

Contaminants, such as oxygen, carbon, and other residual gases in the vacuum environment, can adversely affect cathode performance. These contaminants can form compounds with barium or tungsten, reducing emission efficiency and accelerating surface erosion. Proper vacuum conditions and device sealing are essential to minimize contamination.

Material Quality

The quality and purity of the tungsten and barium used in the cathode significantly influence its lifespan. Impurities or inconsistencies in the materials can lead to uneven emission, localized overheating, or premature failure. High-quality manufacturing processes and material selection are therefore critical.

Current Load

The amount of current drawn from the cathode also affects its longevity. Excessive current densities can increase the rate of barium evaporation and thermal stress on the cathode, leading to quicker wear and reduced functionality. Operating the cathode within its specified current limits helps prevent premature degradation.

Mechanical and Thermal Stress

Mechanical stress, such as vibrations or impacts, and thermal cycling (repeated heating and cooling) can cause cracks or fractures in the cathode structure. These defects can disrupt electron emission and shorten the cathode’s service life. Careful handling and consistent operating conditions reduce the risks associated with stress.

Vacuum Conditions

The vacuum level in the device plays a critical role. A poor vacuum allows residual gases to interact with the cathode surface, forming oxides or other compounds that hinder emission efficiency. Maintaining a high-quality vacuum environment is essential for cathode durability.

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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What Are the Advantages of Using Barium Tungsten Cathodes in Electron Emission Devices?

Barium tungsten cathodes are widely used in electron emission devices, including vacuum tubes, cathode ray tubes (CRTs), and X-ray tubes. These cathodes are renowned for their exceptional performance characteristics, which make them indispensable in applications requiring reliable electron emission. Below are the primary advantages of using these cathodes in such devices.

High Electron Emission Efficiency

One of the foremost advantages is their ability to emit electrons efficiently. The incorporation of barium, which acts as a reducing agent, significantly lowers the work function of tungsten. This reduction in work function enhances thermionic emission at relatively lower temperatures, making barium tungsten cathodes highly energy-efficient compared to pure tungsten cathodes.

Thermal Stability and High Melting Point

Tungsten has an extraordinarily high melting point (3422°C), providing excellent thermal stability to the cathode. This allows the cathode to operate reliably at high temperatures, which are often required for efficient electron emission. The addition of barium ensures that the cathode maintains stable electron emission properties even under prolonged operation in extreme conditions.

Longevity and Durability

BaW cathodes are highly durable and exhibit long operational lifespans. The protective oxides formed by barium during operation help reduce surface degradation and maintain consistent emission properties over time. This reliability minimizes the need for frequent replacements, reducing maintenance costs in long-term applications.

Enhanced Current Density

Compared to other cathode materials, baW cathodes can support higher current densities, enabling them to handle demanding applications effectively. This makes them particularly suitable for high-power electron emission devices, such as klystrons, magnetrons, and high-frequency vacuum tubes.

Versatility in Applications

Due to their robust performance and reliability, BaW cathodes are employed across various fields, including medical imaging (X-ray tubes), broadcasting (television and radio transmitters), and scientific research (electron microscopes).

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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Tungsten Plate Price in Late January 2025

 3.5x96x560mm tungsten plate price is 510.00 USD/PC in the second half of January 2025, EXW XIAMEN, CHINA. 

Tungsten plates can be as thin as 0.01mm or as thick as 127mm, with widths typically ranging from 10mm to 800mm. They can be used in many different applications and is valued for its corrosion resistance, ability to withstand extremely high temperatures, and ability to create rigidity and hardness when combined with other metals in the alloy.

Tungsten is used in the aerospace, research, building materials and light bulb industries. It is the predominant metal in electric furnace heating elements, as well as in any assembly where high pressure/high temperature environments are expected. Plates made of tungsten are commonly used in furnace construction, but are also important for making parts for the electronics and semiconductor industries, and can be found in a variety of lighting, vacuum plating, electronic vacuums and shielding.

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Lanthanated Tungsten Electrode Price in Late January 2025

 Ø3.2x175mm lanthanated tungsten electrode price is 2.20 USD/PC in the second half of January 2025, EXW XIAMEN, CHINA.

WL20 electrodes contain at least 1.7% to 2.2% lanthanum for excellent arc starting, low burnout rate, good arc stability and excellent re-ignition characteristics. They are ideal if you want to optimize your welding capabilities. They can work well on either AC or DC electrode negatives with tips, or they can be used with AC sine wave power supplies. The tungsten electrode adding with rare earth element lanthanum holds sharp tips well, which is an advantage for welding steel and stainless steel on DC or AC from square wave power sources.

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Electron Beam Tungsten Filament Price in Early January 2025

The price of φ0.65mm electron beam tungsten filament is USD 2.50/PC, EXW XIAMEN, CHINA in the first half of January 2025. 

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 Early January 2025

The price of φ1.6x175mm ceriated tungsten electrode is USD0.50/PC, EXW XIAMEN, CHINA in the first half of January 2025. 

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 June 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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