THE EFFECT OF HEAT TREATMENT ON ELECTRICAL CONDUCTIVITY AND ELECTROCHEMICAL CORROSION RATE FOR    AL-ZN-MG ALLOY 7020-T6 IN SEA WATER

Naser Majeed, Murooj; Hashim Jryian, Ali; Ibrahim Ismail, Muammar

	THE EFFECT OF HEAT TREATMENT ON ELECTRICAL CONDUCTIVITY AND ELECTROCHEMICAL CORROSION RATE FOR AL-ZN-MG ALLOY 7020-T6 IN SEA WATER
AL-TAQANI
Article 1, Volume 27, Issue 4, 2014, Pages 0-0
Authors
Murooj Naser Majeed; Ali Hashim Jryian; Muammar Ibrahim Ismail
Abstract
This work involves study the effect of heat treatments on electrical conductivity and electrochemical corrosion of Al-Zn-Mg alloy 7020-T6 .The specimens were prepared with dimensions of 100 × 50 ×6 mm and subjected to solution heat treatment at 500℃ and artificial ageing at 180℃ for (1,2,3,4) hours , then the electrical conductivity for all sheets were measured. It was found that the electrical conductivity increases with increasing of aging time then decrease because of the precipitating phases that have been identified after conducting a test of X-ray diffraction as well as electrochemical corrosion test which investigated by Potentiostat, for specimens with dimensions 1.5×1.5×2 mm according to ASTM G71-31 . Open circuit potential was measured and compared with the position of metal in the galvanic series then voltage was increased by ±100 mv , at scan rate 10mV/sec , corrosion parameters were calculated according to Tafel extrapolator method, increase in the current and calculate the corrosion current. It was found that the increasing of ageing time causes increasing of phases precipitation, that effect on electrical conductivity and then corrosion rate .

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