TRIBOLOGICAL BEHAVIOR OF TIC THIN-FILMS GROWN BY PULSED LASER DEPOSITION (PLD)

The tribological behavior of titanium carbide (TiC) thin films grown by excimer pulsed laser deposition (PLD) was investigated. The purpose of this work was to evaluate the effects of film deposition temperature, substrate hardness, and counterface hardness on the friction and wear behavior of the TiC films. Films were grown at room temperature (RT) and at 300-degrees-C. Substrate hardness was varied by selecting the heat treatments of the 440C stainless steel (SS) disks; the counterface hardness was varied through materials selection (eg. hardened 440C SS and sapphire). Friction coefficients and wear lives were determined for each film/substrate/counterface configuration. The wear surfaces were investigated by optical and scanning electron microscopy. The PLD TiC films grown at room temperature and 300-degrees-C were stoichiometric and crystalline, with a grain size of 2-10 nm. The films displayed very good adherence in the wear tests, and their friction coefficients ranged from 0.2 to 0.4 against 440C SS and sapphire balls, which compares well with data of films grown with conventional methods. The wear life of the films deposited on annealed SS was lower than that for films deposited on tempered SS. Films deposited at RT showed a better wear resistance than films deposited at 300-degrees-C, whereas the wear of the SS balls was lower in the tests with the films deposited at 300-degrees-C. The impact of this work is: (i) hard, wear resistant TiC films can be deposited by PLD at temperatures as low as room temperature; and (ii) using PLD, the film deposition temperature can be used to control film properties.