The chemical protection layer includes the oxide film and phosphating film of ferrous metal, the oxide film of magnesium alloy; Thickness, only the hard oxide film of aluminum alloy needs to measure its thickness, other anodic oxide film of aluminum should be measured when necessary. In addition to the thickness of oxide film of aluminum or aluminum alloy, eddy current Thickness Gauge and metallographic microscope can be used. The thickness can also be determined by the following methods:
1) Voltage breakdown method The voltage breakdown method measures the thickness of the aluminum anodic oxide film, which is to use a special breakdown voltage meter to measure the breakdown voltage value of the oxide film, and read it directly from the instrument dial or look it up from the comparison table film thickness.
2) Weighing method When measuring the thickness of aluminum anodic oxide film by weighing method, first make a 50mmx100mmx 0.8mm sample with the same material as the work to be tested, and put it into the tank for oxidation together with the workpiece after pretreatment. After oxidation, after cleaning, drying, weighing and recording the weight of the sample, remove the oxide film in the following solution.
