In: Chemistry
17.27 Briefly describe the two techniques that are used for galvanic protection.
galvanic protection is a method used to protect the metal form corroision. galvanic anodic protections and impressed current method are the two methods for reducing corrosion.
galvanic anodic method : In this method a sacrificial is electrically coupled to the metal to be protected.The current form the sacrificial anode is intense enough to prevent the positive current from leaving the anodes in the structure to be protected.this process reduces the corrosion of metal almost zero.here the sacrificial anode is a metal or alloy is more reactive than the object protected.the anod eis preferentially oxidizes and givingup electrons to the metal, protects the metal from corrosion.
impressed current method: for the larger structures sacrificial anode can not produce sufficient current for the complete protection of the metal.this impressed current method works by delivering the control amounts of DC currents to the surfaces submerged in water with aid of ultra relaible zinc electrodes as well as combined metal oxides.Thre electrical current is continiously monitered by the ICCP systems helps in preventing corrosion prior to its attack.