If you are asked to list the faults that bother you in potassium chloride galvanizing, I believe you will not hesitate to say coating burning. In the Hull cell test, if there is burning at the high end of the test piece, then we can use it to judge the mass concentration of zinc chloride in the plating solution.
Judge the mass concentration of zinc chloride from high end burning
Several causes of high end burning
1.If the PH value is too high, the PH value in the cathodic interface liquid layer in the high zone will be even higher, which will easily generate metal hydroxides and oxides entrapped in the plating layer, resulting in burnishing of the plating layer.
2.The mass concentration of the main salt of potassium chloride galvanized is too low, the concentration difference in the high area is too large, resulting in hydrogen ion discharge, the PH of the liquid layer at the cathode interface rises, and it will also cause burning.
3.The high mass concentration of additives results in excessive cathodic polarization and a widening of the high end scorch zone.
How to identify causes
Step 1: Measure the pH value with a precision pH paper and adjust it to the normal value.
Step 2: Observe the brightness of the plated layer and confirm whether the mass concentration of additives is appropriate. And then replenish 8g/L boric acid.
Step 3: Potassium chloride galvanizing solution was added to the 250 mL Hull cell and static plating was performed for 2A x 5 min.
There are three results that occur when you do this test: a. If the burnt area of the test piece is 1~2 cm, it indicates that the mass concentration of zinc chloride is normal; b. If the burnt area of the test piece is greater than 2 cm, it means that its mass concentration is low; At this time, we can properly supplement zinc chloride, and then test plating; c. If the test piece does not appear burnt, then the mass concentration of zinc chloride is high.
In the Hull cell test, if there is high end burning of the test piece, then it means high defect rate in the large production.Then when delivering the goods to the customer, there will be some unnecessary disputes, such as being deducted by the customer, the customer is not satisfied with your service and quality.
Therefore, many electroplating factories will seek a specialist who can find out causes and solve the problem timely in the production. A plating solution supplier who can provide a full set of technical service program is a qualified specialist.
Over the past 20 years since the establishment of Bigely Technology, we have provided technical service solutions to many electroplating plant customers. For example, we are capable of assisting customers in troubleshooting and solving the previously mentioned potassium chloride galvanizing burnout failure. We will also provide customers with reasonable advice on the use of potassium chloride galvanizing brightener.