Sources of Tin
Tin is another wear metal expected in any machine using plain bearings, as lead and tin are the most predominant metals used in Babbitt overlay, with lesser amounts of copper, antimony, and/or arsenic. Typically, increasing levels of tin from this layer are not considered actionable, not until metals like copper or nickel from a lower layer begin appearing.
Tin may also appear in newer engines or rebuilt engines from the piston overlay that is used, or from bushings used in reciprocating applications.
Lead and tin may also appear due to leaching from the solder used to attach cooler tubes, often in conjunction with an increase in Acid Number; however, the common action is to simply change the fluid.
Watch for the next article in the Elemental Spectroscopy blog series: Nickel
