Characteristics of anodizing behavior

Although various anodizing techniques have been developed, which differ from one another for their different anodizing phenomena or coating performance, they do share some common characteristics. 

An anodizing process may display different stages under potential control and current control modes. Generally speaking, a complete voltage-controlled anodic polarization curve of a Mg alloy under a potential control mode may be classified into four regions (1) primary passivity (2) breakdown of primary 

1 Schematic illustration of anodizing stages (a) anodic poiarization curve under a potentiai controi and (b) dependence of cell potential (bath voltage) on anodizing time under a current control mode. 

An anodized coating/film can be characterized by its thickness, composition and microstmcture. These parameters are important to its corrosion protection performance. 

2 Dependence of oxygen evolution and current efficiency on cell voltage under constant electric charge (18C/cm ) (Shi et al., 2006b). 

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