Galvanized wire coating rough, passivation film is not bright, bath temperature is too high. If the cathode current density is too high, zinc content in the bath is too high or sodium hydroxide and DPE content is too low; Solid particles or excessive foreign metal impurities in the electroplating solution can cause such problems. Solution: If the coating of large galvanized wire is rough, there may be solid particles in the plating solution. If the roughness of the part is severe, the current density may be too high.
If the zinc coating is good, but in 3% nitric acid when the light, the coating has dark shadow, passivation occurs when the film is brown, may be caused by foreign metal impurities such as copper or lead in the galvanizing liquid. When problems occur in the process of galvanizing large coil galvanized wire, the temperature and current density are checked first, and then the content of zinc and sodium hydroxide in the plating solution is measured and adjusted through the analysis of the plating solution. Whether DPE content is low can be determined by hull cell test.
If the coating roughness is not caused by the above reasons, it may be caused by impurities in the plating solution. Can take a small amount of electroplating solution, filtration test, and then take a small amount of electroplating solution, with zinc powder treatment after the test, check the problem is solid particles or copper, lead and other foreign metal impurities caused by. One by one, it’s not hard to find the cause of the problem. Galvanized iron wire coating blister, poor adhesion.
Poor pretreatment before plating; Bath temperature is too low; Poor quality of additives or too many additives and organic impurities will cause poor bonding. The quality of additives also has an effect on coating foaming. Some additives react incompletely during synthesis and continue to polymerize during long-term storage or use. The additive tends to distort the crystal lattice and cause stress, causing the coating to bubble.
When the coating of large galvanized wire is blistered in the process of galvanizing, the bath temperature should be checked first. If the bath temperature is not low, and then strengthen the removal of oil before plating, to prevent the base metal in acid corrosion. If you pay attention to these problems, the bubbling phenomenon still exists, it should pay attention to the dosage and quality of additives, then you can stop adding additives, with high current electrolysis for a period of time, to reduce the content of additives, observe whether the bubbling phenomenon is improved. If there is no improvement, check whether the additive has been stored for too long or whether it contains too many impurities.
Post time: 30-06-22