Study Of Full Organic Corrosion Inhibitor Prescription In Engine Antifreeze Fluid

In the field of engine antifreeze fluid (also called coolant), the problem of freezing can be simply solved and the available methods are successful, therefore, the main difference in antifreeze fluid is the different prescription of corrosion inhibitor. According to the prescription be used, antifreeze fluids include inorganic antifreeze, inorganic-organic antifreeze and full organic antifreeze. Full organic engine antifreeze fluid is popular because its obvious superiorities including decreasing operation cost and dispose of waste fluid, those antifreeze fluids could work for three years or more. But there are less full organic antifreeze at present and most prescription of corrosion inhibitor are high cost and toxicity.This thesis is focused on the effect of the metals used in engine cooling system when they are protected by full organic inhibitors. Testing methods includes electrochemical techniques, such as Tafel polarization curve and linear polarization, which are mostly used in screening organic corrosion inhibitors from plenty of organic compounds and studying out the prescription, Sebacic acid and phytic acid are excellent inhibitors of corrosion in the solution of antifreeze fluid. The main compositions in the prescription are sebacic acid and BTA, the best concentration of them are 3g/L and 0.5g/L, all kinds of metals have good inhibition efficiency upwards 90% in 88℃. Two kinds of carboxylic acid and a surfactant which have good synergistic effect with sebacic acid are added into the prescription, the total concentration of the corrosion inhibitor prescription is 6g/L, pH=9.0-10.0. The results of static weight loss proved that the mass change rate of all kinds of metals are notably under the limit of standard, the rate of steel and cast aluminum could controlled under +0.03mg/cm2 and +0.07mg/cm2, the change of preparative alkalinity is about 5%.The selected organic corrosion inhibitor should be nontoxicity or low toxicity, low cost, steady on high temperature, and none additive in the prescription would accelerate the erosion of solder, the stability and bubble tendency could meet the require of standard. At last, the properties of full organic fluid, inorganic fluid and inorganic-organic fluid were compared.