CVD Metals for Corrosion Resistance Applications

The range of chemical reactivity of metals is wide, from the inertness of the platinum group to the extreme reactivity of some alkali metals. The order of metal reactivity follows essentially the order of the electrochemical series which is shown in Table 17.4 for the metals commonly deposited by CVD. 

Metal Electrode Potential (V) Metal Electrode Potential (V) 

The metals above hydrogen in the series react with water to form hydrogen, at room temperature for the alkali metals, at 100°C with steam for magnesium and zinc, and at red heat for manganese and cobalt. 

The resistance of metals to oxidation varies considerably. Gold and most metals of the platinum group do not react at room temperature or at least the reaction rate is extremely slow. Copper, 

The rate of oxidation increases with temperature. Oxygen diffusion becomes more rapid, the oxide film becomes thicker and eventually cracks and spalls off due to internal stress. Oxidation then becomes continuous and rapid. 

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