Stainless steel bearings and full ceramic bearings are both corrosion resistant but the ceramic bearings have greater corrosion resistance. They will both also cope with higher temperatures than chrome steel but ceramic bearings also win here. Stainless steel bearings win the prize for load and speed ratings.
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.
Ceramic bearings have the highest temperature rating. Silicon nitride can cope with 800°C. Next comes 316 stainless steel at 500°C then zirconia at 400°C followed by 440 stainless steel at 300°C. For low temperature use, 316 stainless steel wins at -250°C followed by silicon nitride (-210°C), zirconia (-190°C) and then 440 stainless steel (-70°C).
When it comes to load and speed ratings, 440 stainless steel bearings are the clear winners. Full ceramic zirconia bearings can support roughly 90% of the 440 stainless bearing load and 20% of the speed. Next come silicon nitride bearings with 75% load/25% speed while the clear loser here are the much softer 316 stainless steel bearings with 15% load and roughly 6% speed.
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