There are several important advantages to bearing performance that are due to the improved surface characteristics of silicon nitride balls. Because the microstructure of silicon nitride can be uniformly engineered to sub-micron grain size, the surface of a silicon nitride ball can be finished to <0.15 micro-inch Ra and the roundness is often better than 0.00001 tolerance. This precision results in a coefficient of friction on steel 70% lower than steel-on-steel which translates to a 30% lower internal bearing friction, lower cage wear, lower internal temperatures, and reduced raceway wear.

Silicon nitride balls: Benefits in a bearing

Silicon nitride balls offer many improvements to bearings that traditionally use steel. The material stiffness, light weight, and inertness lower the bearing heat generation while providing stiffer and higher speed bearing capabilities. The surface finish and geometry of silicon nitride balls lowers the bearing vibration and spindle noise as well as improving the speed and life of the bearing. Hybrid bearings with silicon nitride balls clearly set the standard of higher performance machining, longer life, and lower total operating costs.