Nonaqueous in-situ synthesis and tribological properties of PbS nanoparticles of ultradispersion and stabilization

The oil-soluble lead salts and hyper-dispersion stabilizer were synthesized according to design performance. They were characterized with nonaqueous titrimetric analysis, infrared spectrum, inductive coupled plasma atomic emission spectrometrer and gel permeation chromatography. The PbS nanoparticles (n-PbS) were synthesized in-situ in liquid paraffin containing oil-soluble lead salt and hyper-dispersion stabilizer. The accelerated tests were used for evaluating the dispersion behaviors and dispersion stability of n-PbS in liquid paraffin by common speed centrifuge and high speed centrifuge. The diameter and diameter distribution of n-PbS in medium were observed through laser scattering method. The tribological properties of n-PbS as lubricating additive were evaluated with block-on-ring tribotester. The results show that the delamination of n-PbS dispersion system don't come into being through 72 h centrifuge test and 56 h intermittent high speed centrifuge test, the diameter and size distribution of n-PbS are 21.6 nm and 2.8 nm respectively, n-PbS as lubricating additive can effectively enhance the friction-reduction and antiwear ability of liquid paraffin, and the extreme pressure property can increase 100 percent at the content of 0.05-0.3 percent n-PbS.