Nonaqueous in-situ synthesis and tribological properties of CuS nanoparticles with ultra-dispersity-stability

In-situ synthesis, dispersivity and dispersion stability and tribological properties of ultra-dispersity-stability CuS nanoparticles were studied. The oil-soluble copper salts and hyper-dispersion stabilizer were successfully synthesized. The CuS nanoparticles (n-CuS) were synthesized in-situ in liquid paraffin containing oil-soluble copper salt and hyper-dispersion stabilizer. The diameter, diameter distribution and conglomeration behavior of n-CuS in dispersion were observed by freeze-etching replication transmission electron microscopy technique. The tests of centrifuge and high speed centrifuge were used for evaluating the dispersion stability of n-CuS. The tribological properties of the lubricants with and without n-CuS were investigated by block-on-ring tribo-test, respectively. The results show that n-CuS are ellipsoid-shaped with size of about 35 nm. Nano-dispersion has a single-particle-dispersion properties, and don't come into delamination through 72 h centrifuge test and 56 h intermittent high speed centrifuge test. The friction-reduction and antiwear ability of liquid paraffin are effectively enhanced when n-CuS are added, and the best when the content of n-CuS of 0.1%.