know aluminum friends must have a kind of test method of aluminum, the aluminum membrane, but you know, in fact, the quality of different aluminum conversion coating of time there is a difference!
the pros and cons of aluminum components can distinguish when alkali corrosion, such as surface after alkali corrosion has too much film of membrane, membrane or red, it is necessarily containing silicon or high copper aluminum, the aluminum chemical conversion film on the time shortened, otherwise obtained must be difficult to meet the requirements of conductive film layer.
therefore must according to the different aluminum oxide. to do this, different types of aluminum parts are not allowed to tie in the same string, in order to avoid and unable to control their suitable oxidation time.
different types of aluminum by the conductivity after chemical conversion processing and appearance color difference than other craft formula of the oxide film obtained difference is more apparent. high purity aluminum film was slow.