In recent years, with the application of aluminum alloy in industrial production, in order to improve the performance and appearance of aluminum alloy, people began to take the plating process, there are a lot of plating people think that the pretreatment process of aluminum alloy is the same as the plating of ordinary workpieces, not knowing that, due to the specificity of aluminum alloy substrate, if we take the same process as the ordinary plating pre-processing, then it will lead to the problem of the poor bonding of the plating layer with the substrate, so it is necessary to sort out the pretreatment process. Therefore, it is necessary to sort out the pre-treatment process. In this article, let's talk about how to use zinc sinking water.
Primary zinc sinking
In the primary zinc sinking, if it is winter, when the temperature is in the low state, the zinc sinking time needs to take its upper limit, when the temperature is in the high state, the zinc sinking time we need to take its lower limit, the reason for doing so, in order to be able to generate a uniform layer of zinc sinking.
For the primary zinc sinking generated by the zinc layer is loose and porous, poor bonding, can not guarantee the subsequent bonding, so we need to completely remove the zinc layer in the HNO3 tank, and then secondary zinc sinking.
Secondary zinc sinking
When we carry out the secondary zinc sinking, if the time is long, then the generated zinc layer surface layer is prone to loose porous, poor bonding, in which case, it is not conducive to our subsequent plating process.
So, what are the requirements for secondary zinc sinking? Generally speaking, the zinc layer we get needs to have the characteristics of uniformity, meticulousness and denseness, etc. The reason why the requirements for the zinc layer are so strictly controlled is that the secondary zinc deposition is the key link that affects the bonding force, and it is the first factor that affects the quality of silver plating, and if it is not well controlled, then it will result in the parts being returned to the factory.
Generally speaking, the primary zinc sinking is more concentrated and longer than the secondary zinc sinking, in which case the matrix oxides can be completely removed.
We also need to use ultrasonic waves to thoroughly clean the cavities and threaded blind holes of the workpieces after zinc sinking, otherwise the residual lye inside will cause corrosion to the aluminum alloy matrix, resulting in parts scrapping.
Since the zinc sinking process is so important and can have a profound effect on the bonding of the coating, we need to choose a suitable zinc sinking water. Bigely zinc sinking water BC-22 is able to cover the surface of the aluminum alloy with a uniform and dense zinc coating with good bonding. And with the concentrated liquid type, it is easy to build the bath and maintain it.
If you have any demands for zinc sinking water, please feel free to contact us.
