Bearing Selection for Extreme Environments

The demand for bearings to be used in extreme environments has been on the rise due to technological advancements.

For example, equipment used in outer space for solar panels and semiconductors requires that bearings, and bearing components, have special lubrication and be ultra-clean with no trace of surface solvents, which could result in outgassing when exposed to harsh environments.

Furthermore, these types of bearings can see working temperatures exceed 500° C (932° F) which causes conventional grease, or oil, lubrication to evaporate when the bearing is in use.

Bearings that aren’t primed to function and withstand these extreme operating conditions could see a rapid decrease in bearing life – up to a shocking 90%.

Cleaning & Coating Bearings for Harsh Environments

Ensuring there are quality standards and processes in place for these special bearings, is extremely important. At GMN, we divide our quality protocols into two main categories: Cleaning and Coating, each with dedicated quality standards.

One: Plasma Cleaning for Special Bearings

Each bearing component must have a reactive, clean metal surface for the coating to adhere properly. We achieve this using our plasma cleaning equipment.

Plasma cleaning is the process of removing all organic matter from the surface of bearing components using an ionized gas, also called plasma. This cleaning process uses no harsh chemicals thus will not leave any dry residue or solvents on the surface of the bearing.

Once completed, we vacuum dry each bearing component. Our plasma cleaning process enhances coating adherence to our bearing components.

Two: Physical Vapor Deposition (PVD) Coating for Special Bearings

PVD is the process of applying thin deposits of vaporized metal film onto pure metal or alloy. This coating will lubricate the bearing components without burning off or outgassing.

A PVD coating performs as a lubricant for bearing components that operate in extreme environments. Our magnetron machine sputters out a PVD solid lubricant to coat the bearings.

Bearings with a PVD coating have superior hardness, durability and resistance to wear. These coatings also reduce friction on moving parts which is crucial to vacuum environments.

Depending on the bearing application, the PVD sputtering process can serve as protection against:

Cold welding
Damaging heat
Lubrication degassing

All of which could rapidly decrease the lifespan of the bearing.

PVD Coating Equipment

At the GMN manufacturing facility in Germany, we have state-of-the-art Magnetron PVD equipment with sputter technology. Simply put our PVD equipment can run anything that needs to vaporize a solid material and deposit it onto another.

Our PVD equipment is optimized for high precision bearing components and is custom designed for coating complex 3D surfaces without mechanical interference.

PVD Equipment Features:

Coats a wide variety of component materials like metals, semiconductors and ceramics, no matter what the melting point or vapor pressure may be for that material.
Appling layers of coating won’t impact the maximum working temperatures of the components.
Each PVD layer is equally distributed. Our plasma cleaning process ensures that a strong bond will occur between the PVD coating and the bearing component.
PVD layer thickness can vary from a few nanometers (10-9 nm) up to microns (10-6 μ).
PVD coatings produce the least amount of chemical waste.

Selections of PVD Vaporized Metals (for Coating):

Silver (Ag),
Lead (Pb)
Gold (Au)
Molybdenum disulphide (MoS2)

Bearing Component Metal Selections:

Chrome steel (AISI 52100)
Copper
Titanium

Please note: All bearing components, rings, balls and cages, are manufactured from heat resistant high-speed tool steel or alloys. As an alternative, we offer hybrid bearings with ceramic balls made from silicon nitride (Si3N4).

Harsh Environments & Suggested Bearing Design Examples

Types of Harsh Environments

High-Vacuum Environments: Electron-Scan Microscopes, Turbo-Molecular Pumps

Aerospace: Airplanes, Spacecrafts

Semiconductors: Furnace, Cleanrooms

Medical Equipment: X-ray Tubes

Suggested Bearing Design Examples

Bearing Component Details:

Rings and balls: High temperature tool steel
Ceramic balls (Si3N4)
Cage material heat resistant steel

Bearing Component Details:

Rings and balls: High temperature tool steel
Cage material: Heat resistant steel

Bearing Component Details:

Rings, balls and cage made from heat resistant steel
Rings completely gold plated (Au, PVD sputtered)
Dry Lubrication

Bearing Component Details:

Back-to-back preloaded spindle bearing pair
Rings and balls made from SAE 52100 (100Cr6)
Rings completely gold plated (Au, PVD sputtered)
Special Vacuum oil lubrication

Special application: Emergency bearings (touchdown bearing), backup bearings

Rings made from SAE 52100 (100Cr6)
Balls made from silicon nitride (Si3N4)
Full ball complement (no bearing retainer/cage)
Rings completely gold plated (Au, PVD sputtered)
Solid lubrication: Rings MoS2-coated; Balls MOVIC® treated

Shipping & Installation

The bearings receive special treatment, packaging and transportation per the requirements of each order and application. We’re happy to accommodate any special shipping conditions you may have.

We can also store the bearings in a nitrogen-filled box if needed.

We need to ensure that the coating of the bearing can’t get damaged during handling and assembly. Our GMN engineers will help you determine the correct handling procedures and they can help you find the special bearing that’ll meet your needs. Contact us today to talk to our onsite bearing engineers.