Ceramic bearings VS steel bearing

Compared to steel version, ceramic materials offer superior corrosion and heat resistance, higher dimensional stability, and lower density, which facilitates high speed.  

Regarding to the corrosion resistance, 440 stainless bearings have moderate corrosion resistance but struggle with many stronger chemicals and salt water. 316 stainless steel has much greater chemical resistance and can used at sea above the waterline or for temporary submersion if washed down. Ceramics have excellent corrosion resistance to many chemicals including concentrated acids and alkalis and can be permanently submerged in seawater without corroding.

High speed performance. Ceramic balls are about 40% as dense as steel, which means less centrifugal force is developed on the bearings resulting in suppression of heat generation between the balls and outer ring. The result is superior high-speed performance and they can operate at higher speeds.

Ceramic balls have a smoother finish than steel, A high quality steel ball bearing is consider grade 25. The grade number refers to the tolerance per millionth of an inch. A grade 25 is accurate to 25/1,000,000 of an inch. Less expensive ball bearings may be grade 300, which are less round, at 300/1,000,000 of an inch. Ceramic bearings may be grade 5 or 3 , which is a rounder ball bearing. so the vibration and spindle deflection is reduced allowing higher speeds and better performance.

As for the effect on the bearing races, steel balls have a tendency to create cracks in the bearings’ races, while ceramic balls with their smooth finish, actually polish the races over time. The hardness of ceramic balls also allows them to crush any particles that make their way into the ceramic ball bearing, so they don’t cause damage to the races.