The abrasive removal hypothesis states that the material removal occurring during the polishing process is realised because of an abrasive process in which the generally harder abrasive penetrates into the softer workpiece surface and removes material in a similar way as chipping.
Abrasive removal is also possible when hard abrasive particles are inserted between two bodies moving relative to each other, with the particles subsequently
removing material on the softer surfaces. The smaller these abrasive particles are, the finer the surface structures that can be achieved [RABI95, BUCK81].
The abrasive removal hypothesis is particularly important in the metallographic preparation of metallic workpieces.
The Yield Hypothesis
The fact that abrasives that which are softer than the material to be polished can also be used in the polishing process shows the limited validity of the abrasive removal hypothesis. The yield hypothesis was developed as a response to this. The yield hypothesis states that the pressure introduced via the polish foil at the contact locations between the polishing grains and the roughness peaks of the material being polished causes pressure peaks and thus, because of the relative movement, temperature peaks. These temperature peaks (“hot spots”) can reach temperatures of several hundred degrees Celsius and lead to a local plasticization and finally to the melting of the roughness peaks. The molten material then flows into roughness valleys, where it solidifies.