Frictional Behavior of Bismuth-based Soft Coatings

E. BROITMAN; G. PRIETO; BRUNO PILOTTI; W. R. TUCKART

San Diego, USA

Conferencia; 44th ICMCTF, International Conference On Metallurgical Coatings & Thin Films; 2017

ICMCTF

The aim of this study was to analyze the frictional behavior of a bismuth-based soft coating, developed using a novel, eco-friendly and economically competitive synthesis. Bismuth has a non-toxic nature, making it attractive for the development of new tribological applications such as coatings or as oil additives.Bismuth sulfide (Bi2S3) nanoparticles were synthesized in-house by means of an eco-friendly reaction in an aqueous medium under mild reaction conditions, in presence of a surfactant. The obtained particles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Bi2S3 nanoparticles were mixed with a commercial organic varnish in order to generate a soft coating. The coating had a weight fraction of nanoparticles of 17.4 wt% and was manually applied on a SAE 4140 steel disk . The frictional response of the soft coating was evaluated using a pin on disc test (νl=0.02 m/s; p0=1100 MPa; 6 m of sliding speed), using an AISI 52100 steel ball with a diameter of 6 mm as the counterpart. The same test procedure was employed using a commercially available molybdenum disulfide varnish to serve as a reference.Both coatings exhibited similar friction coefficients during the test, with an initial low value (