Frictional behavior of soft Bi2S3 coatings under different load and humidity conditions

Abstract

In high demanding environments, such as in aerospace, mining and heavy duty applications, solid lubricants are the best choice in order to reduce friction and wear, thanks to their resistance to high temperatures and contact pressures.For this purpose, traditional solid lubricants, such as graphite, molybdenum disulfide (MoS2) and tungsten disulfide (WS2) have been extensively used. However, all of them show weaknesses in some aspects. For example, graphite needs moist air, while MoS2 requires high contact pressures in order to properly lubricate. We have accomplished a novel eco-friendly and economically competitive synthesis for producing Bi2S3 nanoparticles, which are attractive for the development of new tribological applications such as coatings or oil additives.The aim of this study was to analyze the frictional behavior of a Bi2S3 based soft coating under variable relative humidity (RH) atmospheres and contact pressures. In addition, its performance was compared to a MoS2 coating generated with the same method.