Development of a Lead-Free Bearing Material for Aerospace Applications

Abstract

Apart from providing excellent anti-friction and anti-wear properties of bearing alloys, lead is considered an environmentally hazardous material. Lead content in bearing bronze varies depending on the application and, in some cases, is fairly low. However, disposal of waste material from fabrication processes, disposal of used bearings, and contamination of lubricants can cause serious environmental and health concerns. In some countries, regulations prohibit the use of lead in plumbing applications, bearing materials, and electronic equipment. The main objective of this project is to develop a lead-free environmentally friendly copper-based bearing material for high speed/load applications. In this study, bismuth was selected to replace lead in alloy C93700, and two different lead-free materials were cast in addition to the standard bearing material. This comparative study is focused on mechanical properties, microstructure, and tribological characterization of the candidate replacements for the lead-containing bearing alloys.