As engine oils continue in service, combustion gases combine with the oil resulting in the formation of acids that are corrosive to the surfaces with which they come in contact. Sulfur in fuel may cause the formation of strong sulfuric acid. Alkaline additives are used to neutralize this effect. The reserve alkalinity or the remaining ability of these basic compounds to neutralize acidic compounds is measured by the total base number (TBN) of the oil. Sulfation correlates inversely with TBN. Sulfation as determined with an infrared spectrometer, such as the FluidScan, is a measure of the decline of a lubricant's ability to combat acidity. It complies with ASTM E 2412.
Applicable Spectro Products: