Clean the Metal Surface completely either by using Solvent Cleaner / Detergent / Acidic Powder like Sulfamic - CITRIC / Surfactant. After cleaning Passivate with Sodium Nitrite Standard Solution.
Other Names
Sodium Nitrate 0.5 Percent for Passivation
Note
Carbohydrazide also passivates metals and reduces metal oxides converting ferric oxide to ferrous oxide and converting cupric oxide to cuprous oxide.
Carbohydrazide reacts directly with oxygen. It helps prevent oxygen damage and continues to passivate metal surfaces during wet lay-up. Carbohydrazide can also be used as a curing agent for epoxide-type resins.
