We investigate the diffusion interaction and quantitative analysis of zinc dialkyldithiophosphate (ZDDP) mixed with lube base oil (LBO) at different concentrations using terahertz time-domain spectroscopy (THz-TDS). When the concentration exceeds 6.78%, the characteristic absorption peaks exhibit significantly shift, and the absorption coefficient peak value is nonlinear against concentration. Moreover, the absorption coefficients of mixed samples follow the Beer's law at a concentration below 6.78%. The quantitative analysis enables a strategy for monitoring the formulation of lubricating oil in real time.
© 2011 Chinese Optics Letters
(070.4340) Fourier optics and signal processing : Nonlinear optical signal processing
(160.4760) Materials : Optical properties
(190.4400) Nonlinear optics : Nonlinear optics, materials
(300.6495) Spectroscopy : Spectroscopy, teraherz
Spectroscopy, imaging, and sensing using terahertz radiation
Lu Tian, Kun Zhao, Qingli Zhou, Yulei Shi, Dongmei Zhao, Cunlin Zhang, and Songqing Zhao, "Diffusion interaction and quantitative analysis of zinc dialkyldithiophosphate content in lube base oils in terahertz regime," Chin. Opt. Lett. 9, 110010- (2011)