Preparation And Evaluation Of Schiff Base Corrosion Inhibitor On Aluminum In Hydrochloric Acid Medium

Aluminum is one of the most common metals with some advantages such as light weight,good physical properties and is widely in production and life.Aluminum material is often used in condensers,air coolers and other equipment.The long-term operation of these devices will inevitably produce scale,and scale generation can affect heat transfer efficiency.However,the corrosion potential of aluminum is very low in the acid solution which is easy to be corroded.Therefore,this paper mainly explores the corrosion inhibition of aluminum in5%hydrochloric acid system.Schiff base is chosen as the corrosion inhibitor mainly because of the high corrosion inhibition performance of Schiff base in preventing metal corrosion.Schiff base characterized by containing C=N double bond is aromatic can form a large?-?domain with a stronger coordination ability.In addition,the synthesis process of Schiff base corrosion inhibitor is simple with the low cost and has great market application value.In this paper,three kinds of efficient Schiff base corrosion inhibitors were synthesized:Schiff base 1,Schiff base 2 and Schiff base 3.The corrosion rate of the aluminum test piece in the 5%hydrochloric acid with Schiff base was measured by weight loss method,and the thermodynamic data of the three Schiff base corrosion inhibitors on the aluminum surface were calculated.The optimum dosage of the three reagents was 0.06,0.06 and 0.08, respectively.In the thermodynamics process,the three Schiff base corrosion inhibitors meet the G⁰<0,Schiff base adsorption process on the metal aluminum surface is spontaneous;?H⁰<0,Schiff base adsorption process is an exothermic process;?S⁰>0,The process of adsorption of Schiff base on the surface of metallic aluminum increases the degree of chaos.The adsorption kinetics of the Schiff base on the surface of the metal aluminum decreases with the increase of the temperature.The adsorption capacity of Schiff base on the surface of metallic aluminum decreases with the increase of temperature,so the corrosion rate of Schiff base is correspondingly reduced.The electrochemical data show that the corrosion current of the aluminum test piece are obviously reduced after adding the Schiff base corrosion inhibitor,and the slope of the cathode tower has changed greatly.Such results show that the three Schiff base corrosion inhibitors are cathodes type corrosion inhibitor.Three kinds of Schiff base corrosion inhibitor were respectively mixed with furfural,1227 and benzaldehyde resulting in nine kinds of synergistic corrosion inhibitor including Schiff base 1 with furfural,Schiff base 2 with furfural,Schiff base 3 with furfural,Schiff base1 and 1227,Schiff base 2 and 1227,Schiff base 3 and 1227,Schiff base 1 and benzaldehyde,Schiff base 2 and benzaldehyde,Schiff base 3 and benzaldehyde.The experimental results show that the corrosion inhibition effect of synergistic corrosion inhibitor is better than that of individual component corrosion inhibitor.Weight loss method research shows that the best ratio of nine kinds of synergistic corrosion inhibitors is 3:2,1:1,4:1,3:2,1:1,1:1,1:1,1:1,1:1.Electrochemical data show that the synergistic corrosion inhibitors are cathodic corrosion.The corrosion inhibition performance of the synergistic corrosion inhibitor is much higher than that of the individual component,but the corrosion inhibition rate is far less than the requirement of industrial cleaning application.Therefore,the three-component compound corrosion inhibitor is continuously developed.Experiments indicate that Schiff base 3,benzaldehyde and sodium thiocyanate compound corrosion inhibitor J-YS corrosion effect is better.The results of orthogonal experiments show that the corrosion inhibition is the best when the mass ratio of Schiff base 3,benzaldehyde and sodium thiocyanate is 1:4:3.The corrosion inhibition performance of J-YS in 5%hydrochloric acid was studied by weight loss method.The results show that the optimum corrosion inhibition rate of J-YS is 0.07 with the best use of time for less than 16h.The results show that the corrosion inhibitor J-YS is a cathodic corrosion inhibitor.The corrosion inhibitor J-YS is a kind of high efficiency cleaning corrosion inhibitor.At room temperature,the corrosion rate of aluminum can be reduced to0.08013 g·m^-2·h^-1 in 5%hydrochloric acid.