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; Electroplating solution with solid particles or excessive foreign metal impurities, will lead to such problems. Solution: If the large roll galvanized wire to the above coating 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 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 galvanized liquid. When there is a problem in the process of galvanizing, check the temperature and current density first, and then measure and adjust the content of zinc and sodium hydroxide in the bath through the analysis of the bath. Whether DPE levels are 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, after filtration test, then take a small amount of electroplating solution, after zinc powder treatment test, check the problem is caused by solid particles or copper, lead and other foreign metal impurities. Test them one by one and it’s not hard to find the cause of the problem. Galvanized iron wire coating foaming, binding force is not good.
Poor pretreatment before electroplating; Bath temperature is too low; Poor quality additives or excessive additives and organic impurities can cause poor bonding. 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 use. The additive tends to distort the lattice and create stress, causing the coating to blister.
When the large roll galvanized wire galvanizing process coating foaming, first check the bath temperature. If the bath temperature is not low, then strengthen the plating before removing oil, prevent the matrix metal in acid corrosion. If you pay attention to these problems, the foaming phenomenon still exists, it 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, observe whether the foaming phenomenon is improved. If there is still no improvement, it is necessary to check whether the storage period of additives is too long, or whether there are too many impurities in the additives.
Post time: 18-04-23