Tribological properties of bismuth sulfide (Bi2S3) particles as grease additive for aluminum forming operations

Abstract

In the present work, the friction and galling-prevention properties of a lubricating grease with the addition of Bi2S3 particles have been investigated. To achieve this, commercial lithium greases containing Bi2S3, hexagonal boron nitride, and graphite were employed to lubricate steel–aluminum contacts under different tribological configurations, namely reciprocating sliding tests with varying normal loads and sliding speeds and load scanner tests at 25, 200 and 300 °C. The addition of Bi2S3 enhanced the tribological response of the grease in reciprocating tests and provided protection against galling up to temperatures of 200 °C. However, its performance severely deteriorated at 300 °C. Thus, Bi2S3 showed promising properties as an additive for lubricating greases operating under a wide range of normal loads, sliding speeds, and moderate temperatures.