The processing hardness and brittleness of alumina ceramics are introduced

Alumina ceramics mainly have α, β and γ crystal morphology, among which α -Al203 crystal morphology is relatively stable, at 1300℃ I3 and γ crystals almost completely transformed into α crystals. In the crystal form of α -Al203, the atomic bonds formed by aluminum ion and oxygen ion are mostly covalent bonds, ionic bonds or their mixed bonds, so the interatomic binding energy is very high and has strong directivity.

Under normal circumstances, the microstructure of alumina ceramics is equiaxed grains, which are polycrystalline structures composed of ionic bonds or covalent bonds. Therefore, the fracture toughness is low. Under the action of external load, the stress will make the ceramic surface produce fine cracks.

The crack will rapidly expand and appear brittle fracture, so in the cutting process of alumina ceramics, often appear collapse and clear phenomenon, that is, there are small cracks on the ceramic surface.

Its specific performance is that the material is brittle, plastic deformation is small, easy to crack, its hardness is equivalent to the hardness of carbide hard alloy, several times higher than steel.

Usually high purity alumina ceramics density up to 3980(kg-M4), tensile strength up to 260(MPa), elastic modulus between 350-400(GPa), compressive strength of 2930(MPa), especially its hardness up to 99HRA.