Silicon nitride

Silicon nitride has many properties similar to ruby. This is a very hard and wear-resistant ceramic material that can be processed into high-precision spheres. It can also be polished to a very smooth surface finish.

There is no adsorption between silicon nitride and aluminum, so there is no adhesive wear phenomenon that occurs with ruby measuring balls in similar situations. However, silicon nitride has outstanding friction and wear characteristics when scanned on the surface of steel, so its application is best limited to aluminum workpieces.