Published online by Cambridge University Press: 06 March 2019
Additive elements are now included in manufacturing specifications for greases. Texaco uses X-ray fluorescence at lubricants manufacturing locations; however, analyses of greases in the neat form are difficult due to problems with uniform and repeatable filling of sample cups and outgassing of greases during measurements. This preparation procedure allows quantitative determinations of additive elements in a variety of greases using a single analytical program. Having a single method for all greases is important at busy manufacturing locations.
The preparation method involves dilution of samples in a binder powder. This approach eliminates outgassing and overcomes differences among greases such as type of soap, presence of MoS2 and graphite, and varying oil content. The powder absorbs oil and creates a uniform particle structure. Thorough mixing and careful cup packing yield repeatable measurements. The method allows the use of liquid oil standards for calibration, eliminating the need to obtain analyzed greases. Accurate calibrations have been created for both wavelength-dispersive and energy-dispersive spectrometers.