Oxygen stabilized W-Ag films for environmental antibacterial applications
(1. Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China;
2. School of Materials Science and Engineering, Xi’an Polytechnic University, Xi’an 710048, China;
3. Asahi Group Co. Ltd., Kwun Tong, Hong Kong, China)
2. School of Materials Science and Engineering, Xi’an Polytechnic University, Xi’an 710048, China;
3. Asahi Group Co. Ltd., Kwun Tong, Hong Kong, China)
Abstract: Oxygen was added into sputter deposited tungsten films to reduce residual stress of the films, and silver with content up to 14.3 at.% was further added for antibacterial functionalization. The films were analyzed by SEM-EDX, XPS and XRD. Only X-ray diffraction peaks from β-W or W3O phase were detected for the films. Oxygen and silver existed mainly as solid solution atoms in the films. Silver addition decreased hardness (still ≥10.3 GPa) and elastic modulus of the films. The potentiodynamic polarization demonstrated lower corrosion current density of the WO film than that of the tungsten film, and silver changed corrosion behavior of the films. The Ag-depleted tungsten oxide layer on the film surface suppressed the release of silver ions in water. The WOAg films had good antibacterial activity with E.coli bacteria. The WOAg films would be useful in environmental and other antimicrobial applications.
Key words: tungsten film; tungsten oxide; silver segregation; residual stress; antibacterial coating