The mechanical processing of the surface of ceramic parts mainly includes grinding, lapping and polishing. The forms of grinding processing can be divided into surface grinding, internal grinding, external grinding and coreless grinding. These are the mechanical processing methods widely used in the structural ceramic industry.
The influence of grinding processing on ceramic materials
(1) Material strength
There are processing marks and microcracks distributed along the processing groove direction on the surface of the ceramic. These microcracks may expand under the action of external loads, resulting in a decrease in the bending strength of the processed material. The magnitude of the strength reduction is closely related to the depth of surface damage. In addition, the strength of ceramics is directly related to the grain size of the grinding wheel, the grinding direction, etc.
(2) Surface phase change
When grinding tetragonal oxide ceramics (TZP) and partially stabilized zirconia ceramics (PSZ), a stress-induced phase change occurs when the deformation is large and the grinding stress is large, and the phase change to monoclinic zirconia. This martensitic phase change is accompanied by volume expansion, and a compressive stress field is generated in the phase change zone, which is beneficial to improving the strength and toughness of the material.
(3) Residual stress
Grinding will produce grinding residual stress on the ceramic surface. The main factors that form ceramic grinding residual stress are the thermoplastic deformation caused by uneven thermal expansion caused to grinding temperature, and the cold extrusion effect of microplastic deformation. The former produces thermal residual tensile stress, and the latter produces residual compressive stress. With the increase of grinding speed and grinding depth, the grinding residual stress increases significantly, and the residual compressive stress turns into residual tensile stress.
(4) Surface roughness
The surface roughness of alumina ceramics also changes with the grain size. It increases with the increase of grain size. The measurement of roughness shows that the cutting depth from 2.5 to 40 μm has no effect on it, and it has no relationship with the hardness value. This shows that the grinding removal process is related to the grain size, but not to the hardness.
Edgetech specializes in manufacturing a range of high-performance ceramic components, encompassing zirconia, Alumina, silicon carbide, Silicon nitride, aluminum nitride, etc. Renowned for their exceptional thermal stability, electrical insulation properties, high-temperature resilience, and wear resistance, these ceramic parts play a pivotal role in numerous vital industries, including aerospace, electronics, machinery, military, automotive, and beyond.