Study On Corrosion And Protection Of Al And Cu Alloy In Environment With High-Concentration Of Chlorine Ion

Corrosion and protection were always the chiefly problem in cooling system of engine, the appearance of whole aluminium alloy engine makes Al and Cu alloys become the main material in cooling system. Because of oxide layer, Al and Cu alloys have better abilities on anti-corrosion than Fe; this makes more choose space for the select of cooling liquid. The price of crude oil rising higher and higher makes the glycol's price raising and sharpens the cost of automobile. To lower the price of cooling liquid, the search of substitute product is an important choice. The high-concentration CaCl2 solution has wonderful characteristic in low temperature and its price is low. When use in semi-isolated system, the carbonate sediment is little in so long a time, hence it has the basic condition for application in cooling system.The Corrosion protection capabilities of inhibitors in 25%(m/m) CaCl2 solutions have been studied for Al Y112 alloy by linear scanning voltage and Tafel test. The changes of E b and Ecorr and corrosion rate with concentration have been plotted out. Thus we can get the best concentration of inhibitors though those plots. The research in lower temperature shows that the decrease of ion-exchange rate made the corrosion rate of alloy slower. And the research on oxide layer of Al Y112 alloy surface by weightlessness test indicates that the thicker the oxides layer the lower the corrosion rate.The relationship between BTA concentration and coverage has been searched for copper and the changes of E b and Ecorr and corrosion rate with concentration have been plotted out by electrochemical technologies (such as linear scanning voltage, Tafel, open circle potential-time and alternating.). From the ellipsometric study we can know that the prevention of BTA on corrosion productions'transfer, made over potential higher, and the corrosion rate lower, thus become the mostly route on BTA anti-corrosion.The study on compound inhibitors of Al and Cu alloys supplies reference for the use of CaCl2 solutions in true environment. In the result we can conclude that the compound of inhibitors made the corrosion protection capabilities lower for Al Y112 alloy and made the corrosion protection capabilities higher for copper. The temperature's effect was also been calculated, the rising of temperature make the corrosion rate increase both for Al Y112 alloy and copper. Finally we get the best compound plan was 0.2%(m/m) Na2MoO4 + 0.2%(m/m) BTA, and validated by AFM test.