CeB6 cerium boride is a typical hexaboride, which has high melting point, high hardness, low escape work, good chemical stability, strong ion bombardment resistance, high electrical conductivity (its electrical resistivity is similar to rare earth metals) and other excellent properties, so it is widely used in various fields
In the field of electronics industry, CeB6 cerium boride is an ideal hot cathode material, which is widely used in high-brightness point-like electron source equipment, such as SEM, TEM and other electron microscopy and high-current electron source application equipment, as well as microwave tubes, plasma sources, lithography, electron beam welding machine, free electron laser and other equipment. Recent studies have shown that compared with LaB6, which is recognized as the best cathode, CeB6 as a hot cathode material has the characteristics of strong carbon pollution resistance, low evaporation rate and high resistivity, and is more suitable for cathode material. Compared with tungsten cathode, CeB6 has the advantages of high emission capacity and long service life, and is likely to replace tungsten cathode which is still widely used in electron beam welding machines and other equipment. In terms of new materials, high purity CeB6 powder is the basis for the preparation of CeB6 single crystal, polycrystal and composite materials. For example, in the composite BC4-CEB6 /Al, the presence of CeB6 causes internal crack transition, which improves the bending strength and fracture toughness of simple BC4 ceramics [8]. It makes CeB6 popular in the field of composite materials and functional ceramics, and CeB6 is a good fire-resistant and heat-resistant material with special anti-poisoning ability. In addition, CeB6 ceramics have special significance and broad application prospects in aerospace and national defense advanced industries because of their unique magnetic, electrical and superconducting properties.
Oxidation of cerium hexaboride in high temperature air
1) The oxidation of cerium hexaboride in air at 600 ~ 1000℃ was studied by weighing, chemical analysis and X-ray analysis. The effect of cerium hexaboride in air was determined as 2CeB_6+11O_2→2CeO_2+6B_2O_3 (2) In the temperature range of the test, the oxidation amount of the sample per unit surface area (μ) increases with the increase of the acting temperature; The relationship between μ and time (t) can be expressed by μ=αt~k, where α and k are temperature-dependent constants,k is about 0.7 at 800 ° C, and close to 1 at 925 ° C and 1000 ° C. (3) When cerium hexaboride is oxidized in high temperature air, the boron oxide produced may be volatilized; The amount of volatilization increases sharply with the increase of temperature, and the isothermal volatilization rate is close to constant for a long time. (4) Under the same oxidation conditions, cerium hexaboride is easier to oxidize in air than lanthanum hexaboride.
