Vacuum Technology Dry Lubrication

Special applications for GMN bearings with dry lubrication

	Vacuum technology, like electron-scan microscopes, turbo-molecular pumps
	Air - and spacecraft applications
	Semiconductor productions
	Medical applications, for example X-ray tubes

Extreme environment for bearings
High vacuum and temperatures up and above 500° C (approx. 932° F) exclude conventional oil or grease lubrication systems. Function, reliability and life-time of the bearing components are ensured by tribologic solid lubricant layers and systems.

The bearing components like rings, balls and cages are manufactured from heat resistant high speed tool steel or alloys (e.g. NiBe₂). As an alternative, GMN offers hybrid bearings with ceramic components (e.g. balls made from Si₃N₄).

Solid lubrication:
For physically coating of bearing components with tribologic layers GMN uses a PVD sputter coating machine and plasma cleaning device for preliminary treatment.

Depending on application and requirements, the layers serve as wear protection, separating medium to prevent cold welding, transfer- and minimum lubrication, combined with emergency running properties. The friction coefficients range from 0,01 to 0,25 at temperatures up to 500° C (approx. 932° F).

The tolerances of the work piece are not affected by the small thickness of the layer.

For more information about sputter technology applications please go to technology and example.

Development:
GMN carries out further developments and investigations on tribological layer technology in co-operation with research partners like the university of Erlangen and the technical university of Darmstadt. The influences of substratum characteristics as roughness, surface morphology, structural composition as well as layer-characteristics like nucleus formation, crystallization, adhesion, microstructure and internal stress have to be investigated and understood.

For description of tribologic layers, bonding mediators respectively interlayers, GMN uses electron scan microscopy, X-ray and electron diffraction. For investigation of wear behavior GMN works with high temperature, high vacuum tribometer and four ball tester.