The structure of silicon nitride ceramics :
the microstructure of ceramics is the internal structure of ceramics observed under various microscopes (including high-resolution electron microscopes), which contains rich content such as: the existence of different crystal phases and glass phases The size, shape and orientation of grains; the size, shape and distribution of pores; the existence and distribution of various impurities (including added oil), defects and microcracks; and the characteristics of grain boundaries, etc. These factors are integrated stand up. The microstructures that make up the ceramic body all have varying degrees of influence on the properties of the material.

Silicon nitride is an advanced inorganic non-metallic material
. Silicon nitride has high impact toughness. Generally, the flexural strength of pressed products is 500-700MPa, and the highest one reaches 1000-1200MPa; after calcination, the flexural strength is 200MPa. Although 300-400MPa reflects that the indoor temperature compressive strength of the calcined product is not high, but at a high temperature of 1200-1350 ° C, its compressive strength is still not reduced. The high-temperature stress relaxation of silicon nitride is small. For example, it reflects that the calcined silicon nitride At 1200°C, the load is 24MPa, and the deformation is 0.5% after 1000h. Silicon nitride has high strength and high organic chemical reliability. It is a very good high-temperature structural ceramic, and silicon nitride is an atomic crystal.

Application of silicon nitride ceramics in daily life
Silicon nitride has high strength, high temperature resistance, corrosion resistance, thermal shock resistance, oxidation resistance, wear resistance and other excellent properties in aerospace, automotive engines, machinery, chemical industry, petroleum and other fields. Wide range of applications, the main products are silicon nitride bearings, cutting tools, molds, pump plungers, seals, ball valves, pump bodies, vaporizers, filters, drums, drive shafts, thermowells, metal heat treatment supports, crucibles, Liquid aluminum conduit and special refractory materials, etc.

The excellent performance of new high-temperature structural ceramics silicon nitride
structural ceramics should have specific phase composition and microstructural characteristics. Product performance and use effect Taking silicon chloride ceramics as an example, the room temperature and high temperature flexural strength, fracture toughness, hardness, thermal conductivity, thermal shock resistance and oxidation increment of silicon nitride ceramics all vary with the The density increases and increases. The melting point of silicon nitride ceramics is 1900°C (under pressure). Silicon nitride ceramics are still stable when heated to 1450-1550°C in the air.