ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Surface Chemistry of Tribochemical Reactions: Molecular Beam Experiments

J. Lara-Romero, R. Maya-Yescas, J. L. Rico-Cerda, J. L. Rivera-Rojas, F. Chinas Castillo, M. Kaltchev, and W. T. Tysoe

Faculty of Chemical Engineering, Universidad Michoacana de San Nicolás de Hidalgo, MX-58000 Morelia, Mexico

E-mail: lararom@zeus.umich.mx

Abstract: The thermal decomposition of model chlorine- and sulfur-containing extreme-pressure lubricant additives on clean iron was studied in ultrahigh vacuum conditions using molecular beam strategies. Methylene chloride and chloroform react to deposit a solid film consisting of FeCl2 and carbon, and evolve only hydrogen into the gas phase. No gas-phase products and less carbon on the surface are detected in the case of carbon tetrachloride. Dimethyl and diethyl disulfide react on clean iron to deposit a saturated sulfur plus carbon layer at low temperatures (∼ 600 K) and an iron sulfide film onto an Fe + C underlayer at higher temperatures (∼ 950 K). Methane is the only gas-phase product when dimethyl disulfide reacts with iron. Ethylene and hydrogen are detected when diethyl disulfide is used.

Full paper in Portable Document Format: 596ba481.pdf

Chemical Papers 59 (6b) 481–486 (2005)