In fusion reactors, surface coatings such as TiC and TiB 2 are susceptible to the influence of preferential sputtering caused by plasma ion bombardment. The preferential sputtering is the result of chemical, diffusional, and kinetic processes. The kinetic processes are dominant at low energy and moderate ion flux. A Monte Carlo code, TRIPOS, is developed for analysis of the preferential sputtering phenomenon. Argon, helium, deuterium, and tritium ion bombardment of LuFe, CuAu, TiC, and laminated AuPt alloys are simulated. The results from TRIPOS are compared with the results from other theoretical and experimental works. For helium incident on CuAu, TRIPOS gives good agreement with experiment. While TRIPOS shows general agreement with the corresponding program TRIDYN, results for argon on laminated AuPt are not in agreement with EVOLVE. Finally the case of TiC is investigated, where preferential sputtering of carbon atoms under fusion ion bombardment is observed.