Coatings to improve performance

A range of coatings are designed to improve performance and protect bearings from corrosion, wear, friction and slippage.

INA FAG has launched coatings to improve performance and protect bearings from corrosion, wear, friction and slippage.

In some operating conditions, standard designs may reach their limits and in these cases coatings can help improve the bearings' service life.

Coatings are applied to the surfaces of rolling bearing components without forming a material bond, for example by diffusion, between the coating and base material.

In many cases it is sufficient to coat only part of the bearing or one of the partners in rolling contact.

Ina Fag can advise customers when a coating may be appropriate and what type should be used in particular applications.

The coatings protect bearings from corrosion and fretting corrosion including zinc iron coatings for rolling mill applications, zinc nickel for bearings used in automotive engineering and zinc phosphate for applications exposed to seawater.

Corrotect zinc iron coatings are for small bearings and bearing mating parts that need to have a greater resistance to corrosion, for example drawn cup needle roller bearings with open ends and thin walled components in large numbers.

A chemical nickel coating is also available to protect bearing housings and it suits applications within the food industry.

There are also coatings to protect bearings against wear, friction and slippage.

These include a black oxidising coating, which suits rollers and rings for bearings in wind turbines and rail traction motor bearings.

It also suits applications with a minor risk of slippage.

Thin dense chromium coatings provide wear protection in mixed-friction conditions for small ball and roller bearings and are suitable for raceways of high precision bearings and spindle bearings.

A copper coating is available for emergency lubricant on bearing cages, while silver coatings are used for the same purpose on aerospace bearings and titanium nitride offers the user wear protection in jet engine bearings.

Rolling bearings are electrically insulated to prevent passage of electric current.

The ODs and the faces, or alternatively the bore and the faces, are then coated with aluminium oxide.

Two different coating thicknesses are available: a thick insulating coating with a high resistance to prevent current passage even in moist environments; or a thin insulating coating with a low resistance to current passage.

This coating has sturdier edges due to the lower coating thickness.

A thick coating of aluminium oxide is suitable for applications involving three-phase motors and traction motors, while a thin coating suits applications involving traction motor bearings and tapered bearings for axle bones.

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