Choosing a full ceramic bearing will save you the headache of dealing with rust. These bearings are designed to be corrosion resistance and to be used for long periods of time in highly corrosive environments. Where even stainless steel bearings would suffer with rusting, full ceramic bearings will not. However, ZrO2 bearings may degrade and weaken over a period of time while exposed to hotwater or steam.
In the case of hybrid bearings - those with steel races but ceramic balls - the ceramic balls of these bearings will not rust but the rest of the bearing will need to be maintained against rust.
Before selecting either a hybrid or full ceramic bearings, we suggest asking a member of the SMB Bearings team to consult you on the best bearing for your application. You can contact the team here.