Ceramics in vacuum engineering

    Compared with glass materials, ceramics can withstand strong vibration and the impact surface is not damaged; at high frequency and high temperature, the dielectric loss is small, the insulation strength is high, and the loss does not change much with the increase of temperature; it can withstand 700-1000 ℃ High temperatures and dramatic changes in temperature. Therefore, the insulating materials of electric vacuum devices are more ceramic materials.

    Ceramic material is a kind of multi-phase polycrystalline, its main composition is crystalline phase, while containing a small amount of glass phase, and few pores. The crystalline phase is the framework of the ceramic, which acts as a pillar and bridge. The glass phase acts as a binder. Pores are inevitable in ceramic materials. Even very dense ceramics have a porosity of 2% to 6%. Although the glass phase and pores have a certain influence on the performance and process performance of ceramics, the performance of ceramic materials is mainly determined by the composition and structure of the crystalline phase.

    Ceramics used in vacuum engineering are basically divided into three categories: silicate ceramics, oxide ceramics, and special ceramics.

    Ceramics are brittle materials and mostly lack plasticity at room temperature. Ceramic materials are often brittle fractures when they are destroyed. Generally, the compressive strength of ceramic materials is much greater than the tensile strength, and the difference between the two is about 10 times.

(huiputech)