1) The reason for the yellow coating with fine bubbles:

① The plating solution is alkaline; ② The bubbles in the coating are due to the entry of gas particles; ③ The solubility of the anode is too high.

2) The reason for the pinholes and pitting in the coating:

① The pH value of the plating solution is low, hydrogen is precipitated, and the coating is prone to pinholes; ② The plating solution has a lot of trivalent iron ions or the content of organic impurities is too high; ③ The wetting agent content is too low, and the pinholes will naturally increase; ④ The anode area is insufficient.

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