Use of 1H-NMR spectroscopy, diffusometry and relaxometry for the characterization of thermally-induced degradation of motor oils

FRAENZA, C.C.; FÖRSTER, E.; GUTHAUSEN, G.; NIRSCHL, H.; ANOARDO, E.

TRIBOLOGY INTERNATIONAL

ELSEVIER SCI LTD

Año: 2021 vol. 153

0301-679X

We explore the capability of 1H NMR spectroscopy, relaxation and diffusion for the characterization of thermally-induced degradation of fresh motor oils. Temperature dependent measurements of diffusion show a weak sensitivity to thermal degradation. In contrast, both the transverse relaxation at 1H Larmor frequencies of 20 MHz and 400 MHz, as well as the longitudinal relaxation at 60 kHz showed to be sensitive to thermally-inducedeffects at measured temperatures within the range  10◦C to 30 C. Results show that the highest sensitivitysignificance can be reached by fast field-cycling NMR relaxometry measurements at low magnetic fields.