The Difference Between Polycrystalline Diamond and Single Crystal

As the physical properties of single crystal and polycrystalline diamond are different, the applications of these two different abrasives are then naturally different. For example, in the field of semiconductor, when tough materials as sapphire and silicon carbide are needed to be smoothly polished without damage, the use of polycrystalline diamond polishing liquid is more suitable than single crystal diamond. Why is this?

The difference between single crystal and polycrystalline diamond:

The main difference between single crystal and polycrystalline diamond lies in the structure of diamond particles, which can actually be clearly seen under the microscope. Although both abrasives are irregular polyhedral block particles, the polycrystalline diamond grains are arranged in disorder. As a result, it holds good toughness, and can withstand higher stress.

Meanwhile, since the polycrystalline diamond also has the characteristics of large surface area and cleavability, the self-sharpening properties of polycrystalline diamond are also very good. During the grinding and polishing process, as the crystallite particles fall off, the polycrystalline diamond abrasive will continuously expose more of the same rough and sharp crystallites. This means that regardless of the direction of the workpiece, the polycrystalline diamond has a lot of cutting edges. As a consequence, not only can the processing steps of raw materials be effectively reduced, but the production efficiency can also be improved.