ASTM D4951 – Standard Test Method for Determination of Additive Elements in Lubricating Oils by Inductively Coupled Plasma Atomic Emission Spectrometry
Description:
Significance and Use
4.1 This test method usually requires several minutes per sample. This test method covers eight elements and thus provides more elemental composition data than Test Method D4628 or Test Methods D4927. In addition, this test method provides more accurate results than Test Method D5185, which is intended for used lubricating oils and base oils.
4.2 Additive packages are blends of individual additives, which can act as detergents, antioxidants, antiwear agents, and so forth. Many additives contain one or more elements covered by this test method. Additive package specifications are based, in part, on elemental composition. Lubricating oils are typically blends of additive packages, and their specifications are also determined, in part, by elemental composition. This test method can be used to determine if additive packages and unused lubricating oils meet specifications with respect to elemental composition.
4.3 Several additive elements and their compounds are added to the lubricating oils to give beneficial performance (Table 1).
Scope
1.1 This test method covers the quantitative determination of barium, boron, calcium, copper, magnesium, molybdenum, phosphorus, sulfur, and zinc in unused lubricating oils and additive packages.
1.2 The precision statements are valid for dilutions in which the mass % sample in solvent is held constant in the range of 1 % to 5 % by mass of oil.
1.3 The precision tables define the concentration ranges covered in the interlaboratory study. However, both lower and higher concentrations can be determined by this test method. The low concentration limits are dependent on the sensitivity of the ICP instrument and the dilution factor. The high concentration limits are determined by the product of the maximum concentration defined by the linear calibration curve and the sample dilution factor.
1.4 Sulfur can be determined if the instrument can operate at a wavelength of 180 nm.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
ASTM D4950