Research on the Stability Testing of Lubricating Oil Specimens

According to the consistency of comparison samples in proficiency testing, stability testings were carried out for 3 kinds of lubricating oil specimens which were homogeneous. Based on the precision of oil emission spectrometer, the precision indices of these 3 kinds of lubricating oil specimens were obtained by analyzing the results of the preside laboratory test for the first time, then the data of the two tests later compared with the precision indices. The result shows that the stability testings of Fe, Cr, Cu, Pb, Al, Mg, Zn, Na, Sn, Ni, Ag, B, Mo, Ti in all samples were evaluated to be eligible, while the Si in several samples was evaluated to be unstable. The existence of extraneous contamination in the process of detection caused the concentration of Si element increase, which was considered to be the reason of ineligible conditions.