Chinese name: cerium hexaboride
Foreign name: CeB6
Density: 4.80g /cm3
Melting point: 2552 °C
Operating temperature: 1450°C

Definition:
Cerium boride is an inorganic compound with the formula CeB6, which is composed of the elements cerium and boron. Cerium hexaboride (CeB6) has a CsCl structure (belongs to the simple cubic crystal system, the large sphere represents the Ce element), the difference is that the B6 octahedral cluster occupies the position of Cl, and the Ce occupies the position of Cs. It is a refractory ceramic material with a low work function making it one of the highest electron emittance cathode materials known, while it is very stable in vacuum.
Crystal structure:
Cerium boride has a special crystal structure and belongs to the cubic crystal system. Each cerium atom is surrounded by six boron atoms, forming an octahedral structure. The structure of cerium boride crystals is stable and has a special electronic structure, which also provides a basis for its application in materials science.
Nature:
1. Cerium boride is a black crystal with a metallic luster.
2. It has good electrical conductivity and is a high temperature superconducting material.
3. Cerium boride has a high melting point of about 2300 degrees Celsius.
4. It has high hardness and wear resistance.
5. Cerium hexaboride usually operates at 1450°C. Cerium hexaboride, like lanthanum hexaboride, slowly evaporates during the cathode's operation. The CeB6 cathode can maintain its optimal shape for a longer time at an operating temperature of 1850 K, and therefore has a longer life. At the same time, because its evaporation rate is about 30% slower than lanthanum boride, the hot cathode coating of cerium boride is more difficult to remove than lanthanum boride.
Purpose:
1. Cerium boride is often used in electronic devices, electronic vacuum devices and electric shock active materials in high temperature environments.
2. It can also be used as an additive for vehicle emission control catalysts to improve the activity and stability of catalysts.
3. Cerium boride is also useful in some optical applications, such as the optical components of high-intensity lasers.
4. Cerium hexaboride is mainly used for the coating of hot cathode, or the hot cathode is directly composed of cerium hexaboride crystal. Cerium hexaboride (CeB6) and lanthanum hexaboride (LaB6) are often used as some high-current hot cathode coatings. Hexaboride has a low work function, about 2.5 eV, and has a certain tolerance to cathode contamination. Cerium boride cathodes have lower evaporation rates than lanthanum boride at 1700 K, but they become uniform at 1850 K and even higher evaporation rates above that temperature. Cerium boride cathodes have a 50% longer life than lanthanum boride due to their higher carbon pollution resistance. The brightness of the boride cathode is ten times that of the tungsten cathode and its life is 10-15 times that of the tungsten cathode. Some laboratory tests have shown that CeB6 is more tolerant to the negative effects of carbon pollution than LaB6. They are commonly used in, for example, electron microscopy, microwave tubes, electron beam etching, electron beam welding, X-ray tubes, and free electron lasers.
5.CeB6 is also a very stable material, resistant to contamination and degradation, which ensures that its properties remain consistent over time. In addition to its performance advantages, CeB6 is a cost-effective electron source, making it an electron source of choice for a wide range of SEM applications. These applications include imaging, material analysis and spectroscopy.
6. One of the main benefits of using CeB6 as an electron source is its high brightness. Brightness is a measure of the number of electrons emitted per unit area per unit time, and high brightness is essential for obtaining high-quality SEM images. The superior brightness of CeB6 provides a higher signal-to-noise ratio and better image resolution and quality compared to other electronic sources, such as tungsten wires. With CeB6, more current can be utilized as well as a smaller spot size, which results in a higher resolution than tungsten. In addition, CeB6 has a long life compared to other electronic sources, which reduces maintenance and downtime.
Preparation:
Cerium boride can be prepared by the following methods:
1. Direct reduction method: cerium and boron are reacted at high temperature to produce cerium boride.
2. Thermal reduction method in solution: cerium salt and boron are reacted in solution to generate cerium boride.