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What is the reason for the collapse of alumina industrial ceramics?

2018-04-14 09:36:22

Ceramics are brittle, 坣壱屲 alumina industrial ceramics also have a certain processing brittleness, easy to appear in the process of cracking phenomenon, then alumina industrial ceramics collapse phenomenon is what?


Under normal circumstances, the microstructure of alumina industrial ceramics is equiaaxial grain 坣壱屲, which is a polycrystalline structure composed of ionic bonds or covalent bonds, so the fracture toughness is low. Under the action of external load, the stress will cause subtle cracks on the ceramic surface. The crack will expand rapidly and brittle fracture occurs. Therefore, in the process of cutting alumina industrial ceramics, 坣壱屲 often appears the collapse phenomenon, that is, small cracks appear on the ceramic surface.


The processing hardness of alumina industrial ceramics AL203 mainly has α, β and γ crystal forms, of which α-AL203 crystal form is more stable, and almost all I3 and γ crystals change into α crystals at 坣壱屲1300℃. The atomic bonds formed by aluminum ion and oxygen ion in α-AL203 crystal form are mostly covalent bonds 坣壱屲, ionic bonds or their mixtures, so the binding energy between atoms is high and has strong directivity.


The concrete performance is that the material is brittle, plastic deformation is small, 坣壱屲 easy to crack; Its hardness is equivalent to the hardness of carbide carbide, which is several times higher than steel. The strength and hardness of 99 alumina industrial ceramics have decreased, 坣壱屲 according to our test sample, the hardness of 70HRA at room temperature.


1. The separation of the cut part of the material from the machined surface is caused by tensile damage, which is not the result of normal cutting 坣壱屲. 2. The cracking caused by crushing cutting deformation is generally cracking down along the surface of the workpiece, 坣壱屲 at this time due to the cutting tensile stress will be cut and bonded workpiece matrix spalling off together to form a collapse phenomenon.


It should be noted that the greater the tensile stress, the more serious the collapse phenomenon caused by 坣壱屲 may lead to the waste of the whole workpiece.