Study of Potassium Pyrophosphates and Copper Pyrophosphates with Different Quality on Electroplating Results ―― Measurement of Chelating Ability

Measurement Method: Through CH1650 electrochemical workstation in the traditional tri-electrode electrolysis cell, use normal carbon steel (area 1.13cm2) as work electrode, platinum electrode as supporting electrode, and saturated mercury electrode as reference electrode to measure cathode polarizing curve at stable state. Scan rate is 0.5mV/s.


Polarizing Curve


Cathode polarizing curve of carbon steel in different quality pyrophosphate plating solution


Figure 2: Cathode polarizing curve of carbon steel in different quality pyrophosphate plating solution. Red: imported pyrophosphate. Black: Domestic pyrophosphate.


Chelating Ability


Conclusion: From the polarizing curve, carbon steel has a much larger polarizing rate in ACTi’s than the rate in general quality pyrophosphate plating solution. The line slope at high polarizing area of E-lgi polarizing curve shows Tafel slope is 0.27 and 0.15 respectively, a difference of two times. This explains the stronger chelating ability of ACTi’s than that of general quality pyrophosphate plating solution. Excellent chelating ability is the key to pyrophosphate electroplating.