Antibacterial copper-containing titanium nitride films produced by dual magnetron sputtering

There is an increasing interest in reducing bacterial harmfulness in recent years. Copper-containing titanium nitride films were fabricated on commercial stainless steel using hybrid processes combining dual magnetron sputtering. The objective of this work is to obtain antibacterial surface properties through copper doping for consumer products such as household hardware. In the fabrication process, a titanium target was sputtered using a radio-frequency power supply for easy monitoring of the film color. Copper was also sputtered using a DC power supply. In order to optimize the surface properties, multi-layer films were deposited and the relative amount of copper in the films was modulated by the ratio of the deposition time of different targets. The deposited films exhibit superior corrosion resistance and the corrosion current of the treated sample is reduced to about one-sixth of that of the untreated one. The pin-on-disk results show that the treated samples possess low friction coefficients and the wear tracks are observed to be narrow and smooth. The copper-containing films are very effective in killing the bacteria Escherichia coli. A longer TiN deposition time may lead to a more superior antibacterial capability in addition to enhanced corrosion resistance and wear resistance.