Large roll galvanized wire coating rough, passivation film is not bright. Bath temperature is too high; If the cathode current density is too high, the zinc content in the bath is too high or the sodium hydroxide and DPE content is too low; The presence of solid particles or excessive foreign metal impurities in the plating solution can lead to such problems. Solution: First, observe the phenomenon. If the galvanized iron wire is rough to the top, it may be that there are solid particles in the plating solution.
If the roughness of the part is serious, the current density may be too high; If the zinc coating is good, but when the light comes out in 3% nitric acid, there is a dark shadow on the coating, and the film is brown when passivation occurs, which may be caused by foreign metal impurities such as copper or lead in the galvanizing liquid. When there is a problem in the galvanizing process, the temperature and current density must first be checked, and then the content of zinc and sodium hydroxide in the plating solution can be measured and adjusted through the analysis of the plating solution. Low DPE levels can be determined by Hull cell tests.
If the coating roughness is not caused by the above reasons, it may be caused by impurities in the plating solution. You can take a small amount of electroplating solution, filter it for testing, and then take a small amount of electroplating solution, and test it after treating it with zinc powder to check whether the problem is caused by solid particles or foreign metal impurities such as copper and lead. Test one by one and it is not difficult to find the cause of the problem.
Galvanized iron wire coating foaming, binding force is not good. Poor pretreatment before electroplating; The bath temperature is too low; Poor additive quality or excessive additives and organic impurities can cause poor binding forces. The quality of the additive also has an effect on coating foaming. Some additives react incompletely during synthesis and continue to polymerize during long-term storage or long-term use. This additive tends to distort the lattice and create stress, causing the coating to blister.
When the coating bubbles during the galvanizing process of galvanized iron wire, first check the bath temperature. If the bath temperature is not low, then strengthen the oil removal before plating to prevent the base metal from being over-corroded in acid. If you pay attention to these problems, the foaming phenomenon still exists, you should pay attention to the amount and quality of additives, then you can stop adding additives, with high current electrolysis for a period of time, in order to reduce the content of additives, to observe whether the foaming phenomenon is improved. If there is still no improvement, you should check whether the storage period of the additives is too long, or whether there are too many impurities in the additives.
If the coating foaming in the galvanizing process of galvanized iron wire is caused by the poor quality of the additives, on the one hand, the plating solution should be treated, and the treatment method can be hydrogen peroxide and activated carbon. For unused additives, electrolytic treatment is carried out before use to reduce the influence of impurities in the additives on the coating foaming. The deposition rate of galvanized iron wire is slow in the process of galvanizing, and the deep plating ability is poor.
Post time: 19-07-23