Corrosive Method for Co-W Films Based on Double Primary Batteries Principle.

Cobalt-tungsten (Co-W) film is widely used as the protective layer on steel substrates because of its excellent properties. To further improve a certain aspect of such film, it was necessary to study the relationship between its structure and performance. Co-W film was prepared by electro deposition and the film tungsten content changed by varying the duty cycle. Based on the single primary battery principle, it was difficult to show the film’s microstructure, due to galvanic protection by the PCrNi3MoVA steel substrate during the corrosion process. Thus, a new corrosive method for the Co-W film was proposed based on double primary batteries principle. Based on this method, corrosion effects with different tungsten contents and two corrosive methods were studied. The results showed that the corrosive method based on the double primary batteries principle successfully displayed the Co-W film structure and the effects of the wiping corrosive method better than the direct corrosive method. [ABSTRACT FROM AUTHOR]