Effectively improving the extreme-pressure capacity of a class of intercalated zirconium phosphate materials

We studied different long-chain ammonium ions intercalated zirconium phosphate α-ZrP, methylamine intercalated ZrP (MA-ZrP), tetramethylammonium hydroxide intercalated ZrP (TMAH-ZrP), dodecyltrimethylammonium bromide intercalated ZrP (DTAB-ZrP), and stearyl trimethyl ammonium bromide intercalated ZrP (STAB-ZrP) as grease co-additives in combination with isobutylene sulfide (SIB). The grease with co-additives displayed excellent extreme-pressure and anti-wear performance. Moreover, the combination of the longest chain ammonium ion intercalated zirconium phosphate, STAB-ZrP/SIB, had the best tribological properties. In comparison to α-ZrP, the advantage of STAB-ZrP was that it did not form a large area of the dense physical film like α-ZrP on the worn surface, but rather gave the SIB a chance to contact with the fresh metal surface to generate a chemical film. Therefore, the sub-micron physical film and nanoscale chemical film always exist side by side on the contact surface during the friction process. This intercalated α-ZrP/SIB additive has great potential for use in harsh operating conditions.