Polishing fluids have been developed for titanium alloy, which can be machined only with extreme difficulty, using lapping tape coated with SiC abrasive grain on tetoron taffeta. The introduction of sulfurized fatty acid into the polishing fluids greatly improved the polishing characteristics. In this paper, it was cleared that (1) polishing characteristics was not only improved in cases of polishing fluid contained sulfurized fatty acid but also in case of the solution of lwt% ditertdodecylpolysulfide in butylcarbitol. (2) From the results of XPS measurements after polishing operation, when used polishing fluid contained sulfurized fatty acid, a metal oxide phase on the surface was thicker than without sulfurized one. (3) From the results of the reaction analysis of sulfuric molecules on titanium metal surface (4 kinds of conformation) using ab initio molecular orbital method, the total energy calculation showed that H2S molecule reacted on titanium atom with the stabilizing energy of 22.4 kcal/mol and the optimized configuration of the reacted H2S was found at 2.16 Å on the top site of titanium atom and the bond distance was shorter than Ti-S bond distance of 2.42Å in titanium disulfide.
