Friction properties of La-doped Mg/Al layered double hydroxide and intercalated product as lubricant additives

• Mg/Al/La-layered double hydroxide (LDH) was synthesized with La/Al ratio 0.1.
• Mg/Al/La-LDH was intercalated with sodium dodecyl sulfate.
• The friction properties of intercalated product were superior to its precursor.
• The mechanisms were sliding of laminates and the tribofilm formed on the surface.

La-doped Mg/Al layered double hydroxide (LDH) was synthesized and intercalated by sodium dodecyl sulfate. Friction properties of LDHs as lubricant additives were evaluated in four-ball friction and air compressor test. The results showed that Mg/Al/La-LDH was prepared with La/Al molar ratio of 0.1. The interlayer spacing was expanded from 7.662 to 25.663 Å after intercalation. The intercalated product exhibited better tribological property than its precursor in the friction tests. The improved performance was attributed to a reduction in friction between the expanded laminates, good dispersion of the nanoparticles in the medium and an effective tribofilm formed on the contact surfaces.