Preparation of Mg/Al-LDHs intercalated with dodecanoic acid and investigation of its antiwear ability

Layered double hydroxides (LDHs) intercalated with dodecanoic acid have been prepared by anion exchange with Mg/Al-NO3−-LDHs as the precursor under acid condition with water and ethanol as the dispersion medium. The obtained materials were characterized by X-ray diffraction (XRD), thermogravimetric and differential thermal analyser (TG–DTA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and BET. Patterns of XRD and FTIR show that interlayer nitrate ions have substituted with dodecanoic acid and the gallery height has increased from 0.88 nm to 1.99 nm. The interlayer distance of the intercalated materials increases with the increase of pH value due to the different arrangement of interlayer anions. The tribological performance of LDHs precursor and intercalated LDHs in base oil were studied for the first time by using four-ball wear machine and gear testing machine. Experimental results show that the LDHs precursor and intercalated LDHs powder are excellent in friction-reducing, with decreases in friction coefficient by 23.9% and 22.2% respectively comparing with base oil.

Comparable studies of nano Mg/Al-LDHs powder on the anti-wear properties of lubricating oil were carried out on four-ball and gear testing machine. Mg/Al-NO3−-LDHs and Mg/Al-DA-LDHs powder in base oil possess an excellent friction-reducing property, with a friction coefficient at 23.9% and 22.2% which are lower than that of the base oilFigure optionsDownload as PowerPoint slideHighlights
► We synthesized nano Mg/Al-NO3−(DA)-LDHs via coprecipitation and anion exchange.
► The optimal exchanging condition is as follows: water dispersion and pH value of 5.
► The tribological properties of LDHs were studied on four-ball and gear machine.
► We reported nano LHDs as anti-wear materials in lubricates for the first time.
► The greatest decline in friction coefficient of lubricates with LDHs is up to 23.9%.