In the process of preparation of diamond grinding wheel, select abrasive hardness is one of the most important parameters. Hardness of science as follows: material resistance Division or other objects into the surface, can also be understood as the energy needed to produce the local deformation of solid surfaces. Solely on material composition, hardness and strength of the chemical bonds within the material as well as the coordination number related.
There are four main types:
1. Solid matter in chemical bonds, share electrons with a combination of covalent bond, bond is the strongest, therefore the maximum hardness of Covalent crystals such as diamond and silicon carbide;
2. Specific Ionic Crystal consisting of ions combine gravity, hardness structure of ion electricity price increases, ion the shortened for space, as well as enhanced polarization increases, but the material's hardness is hardness of Covalent crystals to small;
3. By free electrons between metal atoms combine to form metallic bonds, because the bond is relatively weak, so the hardness of metals in the middle-low position; 4. by the molecular attraction between particles combine to form molecular bonds, because the bond is the weakest, so minimum hardness of molecular crystals, such as graphite, talc, kaolinite. Depending on the hardness of diamond grinding wheel measuring methods, can be expressed as the scratch hardness, hardness, abrasive hardness, its numerical measurements varies, but its variation similarity, characterized by hardness and greater value.