Black tin Oxide Deposit on Babbitt Bearings

[Carburize]

Does anybody have any references to any research work or investigations on the causes and effects of the black tin-oxide deposits frequently found on small areas of the surface of babbitted bearings?

 

[unclesyd]

Check out this website and see if answer your question.

http://www.machinerylubrication.com/article_detail.asp?articleid=587&relatedbookgroup=Lubrication2

 

[Carburize]

unclesyd - thanks I already found that one when I did a search earlier.

 

[unclesyd]

I have two other articles that say essentially the same thing.

I have seen this problem on several babbitt bearings where there was water, not saltwater, present. These bearings were in turbines and centrifugal compressors. Two of the instances were on a popular make air compressor where the steam turbine is directly coupled to the compressor and share a common oil sump. As you probably know we get steam/condensate by the carbons and into the oil. The water has a Ph 5-6 and thoroughly oxygenated. We don't see this on every turnaround but about a quarter of the time. These machines have been running this way for 25 years.

 

[Carburize]

I see the effect quite a lot on dry units and it appears to be largely a function of fretting damage during transport.