The surface and tribological chemistry of carbon disulfide as an extreme-pressure additive

✍ Scribed by J Lara; K.K Surerus; P.V Kotvis; M.E Contreras; J.L Rico; W.T Tysoe

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 204 KB
• Volume: 239
• Category: Article
• ISSN: 0043-1648
• DOI: 10.1016/s0043-1648(99)00368-3

✦ Synopsis

The reaction of carbon disulfide with clean iron was investigated for temperatures between 623 and 776 K and pressures between 10 and 30 Torr. Film growth is limited by the thermal decomposition of CS at the growing interface and the activation energy for this 2 process is 12.4 " 1.0 kcalrmol. The nature of the resulting film is analyzed using Raman and Mossbauer spectroscopies and by X-ray diffraction, where it is found that the film consists of a non-stoichiometric ferrous sulfide and also incorporates a carbide. This result is in accord with the tribological data where the interfacial temperature in the plateau region of a plot of seizure load vs. additive concentration is ; 1460 K, the melting temperature of FeS. The seizure load increases substantially when the additive concentration exceeds ; 2 wt.% of sulfur and, since carbide formation was detected in the film, this is ascribed to the formation of an iron carbide at higher additive concentrations.