The application of magnesium alloy sacrifice anode in anticorrosion engineering is very much, and it is necessary to use magnesium alloy sacrifice anode in oil and gas pipeline, ship and so on. After the use of the anode for a period of time, it may be because of the thought or environmental factors caused by its passivation can not continue to use, which we need to understand the performance of anode passivation and identify the method of anode passivation, this chapter jiaozuo City Libao light alloy and everyone to understand:

Knowledge 1: Anode passivation performance

If the magnesium anode is passivated, we can tell from the sudden increase in the voltage of the rectifier. Anode plating tank power supply current shows the tank voltage, tank voltage including cathode potential, anode potential umbrella, tank pressure drop and outside the tank pressure drop and so on, all show the change of current density, affect the anode passivation.

However, according to the specific conditions of anode use, different plating tank voltage is not the same. Therefore, if the conductive rod is not in good contact, the parts will fall off, and so on, the anode voltage will rise suddenly. When this phenomenon occurs, we should judge according to Ohm's law that the circuit resistance increases, the voltage increases, and the magnesium anode passivates.

Knowledge two: recognition of anode plate passivation

Such as galvanized zinc alloy sacrificial anode zinc plate dissolution is gray black, when it becomes white, passivation occurs. Let's look at the performance of some other anodic passivation: acid copper plating passivation for black film gray, cyanide copper tin alloy electroplating passivation after black, nickel anode passivation after reddisk-brown passivation film and so on.