Coating foaming, the binding force is not good. Poor pre-plating treatment, low bath temperature, poor additive quality or excessive additives and organic impurities will cause poor binding force. The oil removal and activation capacity of alkaline zincate galvanizing solution is worse than that of cyanide galvanizing solution, so the requirements for pretreatment of large rolls of galvanized wire are higher than that of cyanide galvanizing, and incomplete oil removal or excessive acid corrosion will cause foaming of the coating.
However, the main reason why this kind of bath is easy to bubble is that the adsorption of organic additives on the coating crystal surface, so that the original crystal or some crystal surface can not grow normally, resulting in the development of new crystal nuclei or some crystal faces. Or the attachment of organic additives in the coating obstructs the normal arrangement of the lattice, causing lattice distortion, thereby increasing the internal stress of the coating, resulting in coating foaming.
Generally, the more the amount of additives, the lower the temperature of the plating solution, the greater the adsorption capacity of the additives on the electrode surface, so that the coating has greater internal stress and is easier to foam. The quality of the additive also has an impact on the coating foaming, some additives synthetic reaction is not complete, in the long-term storage period or long-term use process to produce continued polymerization, such additives may easily cause lattice distortion and stress, resulting in coating foaming.
When the coating bubbles, 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.
A factory has done tests, with industrial grade raw material synthesis of DPE – I, when added to the plating solution, the coating foam, and with higher purity of raw material synthesis of DPE – I, added to the plating solution, the coating does not bubble. Then they will be the industrial grade raw material synthesis of DPE – I, before the use of electrolysis for a period of time, and then use, the foaming phenomenon basically does not appear, the factory’s test proved that the purity of the additive has an impact on the coating foaming, should be noted.
If the coating foaming 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 activated carbon or potassium permanganate activated carbon. It is introduced that the plating solution is treated with lg/LBa(OH)2 and 1g/LCa(ocl)2, and the effect is very good. On the other hand, for unused additives, electrolytic treatment is carried out before use to reduce the influence of impurities in the additives on the coating foaming.
Post time: 29-11-23