Preparation and Antiwear Properties of Silver Sulfide Nanoparticles in Microemulsion

Ag_2S nanoparticles were prepared in two different W/O microemulsions,the structure and morphologies of as-prepared Ag_2S nanoparticles were characterized by means of X-ray powder diffraction (XRD),transmission electron microscope(TEM).The tribological propcrties of liquid paraffin containing Ag_2S nanoparticles were evaluated on a four-ball test machine,the worn steel surface morphology were analyzed by using of scanning electron microscope(SEM).Results show that Ag_2S nanoparticles synthesized in two microemulsions,i.e.isooctane/sodium oleate/n-pentanol/water solution(sampleⅠ) and liquid paraffin/Span 80-Tween 80/n-butanol/water solution(sampleⅡ)both possess monocline crystal structure,and exhibit an even grain distribution.They have average particle size of 18nm and 5nm,respectively.The antiwear tests show that Ag_2S nanoparticles dispersed in liquid paraffin processed from liquid paraffin/Span 80-Tween 80/n-butanol/water solution microemulsion exhibit good antiwear properties which can improve load carrying capacity of the base oil remarkably.