Oil, Grease & Cutting Oils; Prepped And Unprepped Painted Metal Analysis; Clean And Greased Sample Metal Analysis - Thermo Scientific XL2 User Manual

5
Common Operations
Metal Sample Prep
Table 2. Prepped and unprepped painted metal analysis
Sample
Ground Surface
Unground Surface
Oil, Grease & Cutting Oils
Table 3. Clean and greased sample metal analysis
Sample
Clean Surface
Light Grease
Heavy Grease
50 Niton XL2 Analyzer User's Guide
Mn Ni
1.49 0.04 0.03
1.34 0.01 0.04
Oil and grease contain a number of elements combined into a viscous substance and applied
to moving parts in order to reduce friction. Grease coatings can remain on component
surfaces after it has been removed from service. Grease can also be applied to a metal's surface
by accidental contact with other materials coated in heavy grease. Metals can also be coated in
oil as a result of cutting and machining processes in manufacturing.
Grease and oil may contain the following elements:
• Aluminum (Al)
• Zinc (Zn)
• Molybdenum (Mo)
• Sodium (Na)
• Calcium (Ca)
An experiment was performed to show how grease on metal surfaces affects XRF results. A
carbon steel sample was cleaned and ground as a control surface for the experiment. XRF tests
were performed on the control surface, and again after light and heavier layers of automotive
wheel bearing grease were applied to the surface of the steel sample. Results are shown below.
Note the elevated levels of molybdenum, cobalt and zinc from the grease.
Mn Ni
1.18 0.001
1.07 0.001
0.96 0.001
If a sample's surface contains lubricants or cutting oil, use a solvent and a clean towel or rag to
remove them before analysis. You may then need to grind the surface to insure good results.
Clean first, grind second, test last.
Cr Mo Ti
0.004 0.011
0.011 2.507
Cr Mo
0.041 0.004 0.001
0.001 0.067 0.033
0.001 0.500 0.062
Zn Co
0.0001 0.03
1.751 0.21
Cu Co Zn
0.001 0.019
0.322 0.416
1.760 3.430
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