Microstructure of iron sulfide layer as solid lubrication coating producedby low-temperature ion sulfurization

FeS is an excellent solid lubricant due to its hexagonal structure, low she ar strength, and high melting point.;A new low-temperature ion sulfurizatio n technology was developed to produce a sulfide layer of varying thickness on AISI 1045 and AISI 52100 steels. It has many advantages compared with th e electrolytic process. Metallography, an SEM equipped for energy-dispersiv e X-ray spectroscopy, and X-ray spectroscopy, and X-ray diffraction were us ed to examine the microstructure of sulfide layers and their structural dep th-profiles. The results showed that the sulfide layer was loose and porous , and no transition layer was found between it and the substrate. The sulfi de layer was composed of iron sulfide and substrate phases. The former incl uded mainly FeS and FeS2. On the top of the sulfide layer, only FeS2 appear ed. FeS was found to become more abundantly with increasing depth below the surface, whereas FeS2 was found in greater quantities in thicker sulfide l ayers. (C) 2000 Published by Elsevier Science S.A. All rights reserved.