Improving the tribological performance of MoS2 soft coatings on humid environments with the addition of Bi2S3

PRIETO, GERMÁN; PILOTTI, BRUNO; TUCKART, WALTER ROBERTO; DENNEHY, MARIANA

Lewinston

Conferencia; Gordon Research Conferences on Tribology 2022; 2022

Gordon Research Conferences

In the present work, the friction and wear properties of composite Bi2S3 -MoS2 soft coatings with different formulations under variable humidity levels have been investigated. The coatings were deposited onto SAE 1010 substrates using an airbrush technique and were evaluated using reciprocant sliding tests under controlled atmosphere conditions. In one set of experiments, the friction response and the durability of the coatings were determined as a function of the formulation of the coating and the level of humidity (ranging from 20 to 80%). Another set of reciprocant tests was performed in dry conditions in order to assess the evolution of tribofilm formation on the counterpart at different sliding distances, using Raman microspectroscopy, laser confocal microscopy, and SEM-EDS.In all cases, it was found that composite Bi2S3-MoS2 coatings exhibit a more stable friction coefficient and durability than neat ones (i.e. pure Bi2S3 or MoS2 coatings) produced with the same technique at all the tested humidity levels. The level of improvement in the tribological response of the coatings depended on the coating formulation and the level of humidity. The coatings with 50% Bi2S3-50% MoS2 tested at 40% of relative humidity had durability 2,600% higher compared to neat MoS2 coatings.It was found that the addition of Bi2S3 contributes to the formation of thicker tribofilms on the counterparts. Also, the tribofilms form quicker in the case of composite coatings than for neat ones.