Layers for Sliding Contact Bearing
According to the number of the main functional bearing layers the bearings may be mono-metal (solid), bi-metal, tri-metal or multi-layer. Most of engine bearings are either bi-metal or tri-metal.
Typical bearings layers and structures are presented in below:
  • Steel back supports bearing structure, provides its rigidity and press fit under severe conditions of increased temperature and cycling loads.
  • Intermediate layer (lining)is a layer located between the steel back and the overlay.
  • Nickel diffusion barrier (nickel dam)is deposited between the intermediate layer and the overlay in order to prevent a migration of tin from the overlay into the intermediate material (copper).
  • Bonding layer is used for good adhesion between the steel back and aluminum-tin alloy.
  • Non-plated bearing material is referred to mono-metal (solid) and bi-metal bearings. No overlays are deposited on the surface of the material.
  • Tin flash is a very thin (max. 0.00004”/1µm) layer of tin applied to the overall bearing surface.