Synthesis and tribological behavior of surface modified (NH4)3PMo12O40 nanoparticles

Surface modified (NH4)3PMo12O40 nanoparticles were synthesized in a mixture solution of water–ethanol with cetyltrimethyl ammonium bromide as a modifying agent. The morphology, structure and thermal properties of modified (NH4)3PMo12O40 nanoparticles were investigated by means of transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectrum, thermogravimetric analysis, and differential scanning calorimetry. Their tribological behaviors were evaluated on a four-ball testing machine. The results show that the modified (NH4)3PMo12O40 nanoparticles as oil additives can improve the load-carrying capacity and antiwear property of the base oil. The rubbed surfaces were investigated by scanning electron microscopy and X-ray photoelectron spectroscopy. It can be inferred that a tribological reaction film was formed, which contributed to the good tribological properties of surface modified (NH4)3PMo12O40 nanoparticles.