Influence Of Elastohydrodynamic Conditions In Highly Loaded Lubricated Contacts On The Wear Behavior Of Tin Coatings Prepared By Rf Bias Sputtering

Extremely hard Tin coatings were deposited onto steel substrates using reactive r.f. magnetron sputtering with an r.f. substrate bias. Their composition, morphology, crystal structure, hardness and wear resistance in lubricated ball-on-disc test were investigated. The nitrogen content varied between 25 and 52 at.% depending on the N 2 partial pressure. Coatings with a nitrogen deficit showed a considerable ε-Ti 2 N content. Stoichiometric TiN was strongly (111) oriented. The coatings with a high ε-Ti 2 N content showed hardness values of up to 4500 HV 0.015. Coated balls were tested in a lubricated ball-on-disc test with a high load and an initial hertzian pressure of 2800 N mm -2 . The coatings showed good wear behaviour. The wear scars of the best coatings, which were not removed even after 20 h of running, showed excellent correlation to elastohydrodynamic theory.