AES depth profiles in Mo-coated 304L stainless steel achieved by RF-magnetron sputtering and influence of Mo on the corrosion in 3.5% NaCl solution

• Mo coating of 304L stainless steel is achieved via RF-magnetron sputtering.
• The AES depth profiles before and after annealing in air (at 973 K) are analyzed.
• The corrosions in NaCl solution of bare and Mo-coated samples are compared.
• Mo-coated steels exhibit better corrosion behaviors.
• The positive action of Mo oxide via its semi-conducting properties is deduced.

Molybdenum-coated 304L stainless steel samples, fabricated by RF-magnetron sputtering, are characterized by Auger Electron Spectroscopy (AES) before and after annealing in air at 973 K. The electrochemical parameters of bare and coated materials, in NaCl 3.5% water solution at 298 K, are derived from the potentiodynamic polarization curves. The corrosion current of Mo-coated samples (before and after annealing) is significantly lower than that of its bare counterpart. The information gained from the AES depth profiles leads us to infer that the positive action of molybdenum on the corrosion behavior may be attributed to the changes induced by the semi-conducting properties of Mo oxide in the passive film.