A chemical drop problem occurred on a piece plated with alkaline Zn and chromate (III) yellow. The hypothesis is that this likely occurred during the process before the piece was plated. Based on SEM-EDS results comparing the chemical drop point to a normal surface, the drop point showed low Cr and high Zn, while O and C tended to decrease compared to the normal surface. Therefore, it is suspected that an alkaline substance had adhered to the piece, reducing the Chromium(III) adhesion. A pH paper test on the chemical drop point revealed a level 12 alkalinity.
This problem occurs randomly on the workpiece. The exact location of the risk cannot be identified. The problem does not occur throughout the workpiece. Some workpieces may have only one point, while others may have multiple points.
- How should I check to see what solution or chemical the chemical drop is from?
- I don't know what caused this chemical drop, whether it was a drop, a mist, or something else. What should I do to find out?
- I have simulated the formation of chemical droplets in the laboratory by dropping the solution from the plating bath or by simulating by creating air bubbles to burst (forming Aerosol) and then proceeding with the chromium(III) plating process. Black defects appeared, the color of which was similar to the chemical droplets on the real workpiece. However, the defects did not appear as round spots and were the same size as the actual chemical droplets.
Chemical Drop Origin
Re: Chemical Drop Origin
