| Metal corrosion is playing an important role in national economy. Although it is inevitable,it can be slowed down or prevented. At present,the main anti-corrosion technologies of metal inelude applications of corrision resistance materials,surface anti-corrosion technology, added corrosion inhibitors,and electrochemical protection. And the added corrosion inhibitor is a simple,inexpensive and applicability of the anti-corrosion methods. In many corrosion inhibitors,the most practieal corrosion inhibitors is the inhibitors whose configuration has N,O,S,P which can provide solitary electronie or have the activity moleeules which have unsaturated bonds. The corrosion inhibitors which have N-containing are studied most in recent years.In this paper, two types of Schiff base compounds have been synthesized, including water-soluble and oil-soluble Schiff-base compounds. Three kinds of water-soluble Schiff base compounds include: 5-sodium salicylaldehyde-2-pyridyl formyl hydrazone Schiff base(H2B), 5-sodium salicylaldehyde-3- pyridyl formyl hydrazone Schiff base(H3B) and 5-sodium salicylaldehyde-4-pyridyl formyl hydrazone Schiff base(H4B); three kinds of oil-soluble Schiff base compounds include: o-vanillin-2-pyridyl formyl hydrazone Schiff base(L2B), o-vanillin-3-pyridyl formyl hydrazone Schiff base(L3B) and o-vanillin-4- pyridyl formyl hydrazone Schiff base(L4B). Them as a metal corrosion inhibitor, Their corrosion inhibitions for different metals in different media were studied by weight loss method, quantum chemistry calculation methods, electrochemical methods and scanning electron microscopy. The three parts of the review, experiments and quantum chemical calculations were introduced in this paper.In the review section, the definition of inhibition and the class of inhibition are presented in this paper, which mainly summarizes the preparation and application status of green corrosion inhibitors, and a primary overview is given of the development of the inhibition about copper and steel. In this paper, a detailed overview is given of the class of and the development of the inhibition of copper and steel.In quantum chemical calculations section, without any symmetry restrictions imposed conditions by ChemOffice2004, the molecular structures of six substituted pyridine hydrazone Schiff-base were constructed. By Density Functional Theory(DFT), using Gaussian 03 program to build the molecular structure of the above optimization, and optimized B3LYP/6-31G * level of the molecule have been calculated, and the molecular structure and the thermodynamic parameters were obtained。and by mathematical and statistical software SPSS Statistics 17.0, using multiple linear regression analysis, the quantitative parameters of the six kinds of Schiff base and the inhibition efficiency of weight loss data carried on linear fit, results showed that: the six compound inhibition efficiency and EHOMO, ELUMO and EHOMO difference, nitrogen and oxygen atom net charge, molecular dipole (D) and thermodynamic parameters have a very close relationship. Predicting the inhibition ability of water-soluble and oil-soluble Schiff base compounds: H4B>H3B>H2B and L2B>L4B>L3B.In the experimental section, first of all, using x-pyridine carboxylate (x = 2,3,4) and hydrazine hydrate was synthesized x-pyridine hydrazine; then refined salicylaldehyde, refined aniline, sulfuric acid and anhydrous carbonate sodium synthesized 5-sodium salicylaldehyde; 5-sodium salicylaldehyde and hydrazine x-pyridine was synthesized three kinds of water-soluble Schiff base compounds; o-vanillin and x-pyridine was synthesized three kinds of water-soluble Schiff base compounds. the molecular structure of the seven compounds were characterized by infrared spectroscopy (IR), ultraviolet spectroscopy (UV), nuclear magnetic resonance spectroscopy (1H-NMR), thermogravimetric(TG/DTG) analysis and elemental analysis.Second, three kinds of water-soluble Schiff base compounds of copper in neutral solution(3.5% NaCl) and Q235 carbon steel in acidic solution(1mol/L HCl) and corrosion behavior were studied by weight loss method, electrochemical methods and scanning electron microscopy analysis. Weight loss experiments show that the three compounds for the two metals have good corrosion inhibition efficiency, and increases with concentration, the order of inhibition capacity is: H4B>H3B>H2B; the correctness of the conclusions of quantitative calculation was verified. Polarization curves indicate that: the three kinds of water-soluble corrosion inhibitor of the optimal concentration is 75mg/L at 35℃, and they belong to a mixed type corrosion inhibitor; AC impedance results show that three kinds of water-soluble corrosion inhibitor did not decomposition in corrosion solution. Scanning electron microscope figure shows that the three compounds formed a compact, complete adsorption film in the copper surface, the corrosion rate of metals in the corrosive medium were inhibited effectivelyThird, according to the solubility of three kinds of oil-soluble Schiff base compounds, using anhydrous ethanol as solvent, by self-assembled monolayers (SAMs) technology, the corrosion behavior of the self-assembled film copper electrode in neutral medium (3.5% NaCl) and Q235 carbon steel electrode self-assembled film in acidic medium(1mol/L HCl) were studied by weight loss method, polarization curves, AC impedance method. Cyclic voltammetry and scanning electron microscopy analysis. The results show that the three kinds of oil-soluble corrosion inhibitor for the two metals have good corrosion inhibition, inhibition efficiency up to 90.58%, the order of inhibition capacity: L2B>L4B>L3B; three compounds formed a compact, complete adsorption film in two kind of metal surface at room temperature, they belong to cathode-based mixed corrosion inhibitors, and they did not decompose in the self-assembly film and corrosion experiment. Finally, Adsorption kinetics and adsorption thermodynamics of water-soluble corrosion inhibitor in the Q235 carbon steel surface were studied in 1mol/L hydrochloric acid. Bockirs replacement model and statistical model of adsorption thermodynamics results show that water-soluble corrosion inhibitor adsorption in carbon steel surface is a process of exothermic and entropy reduction, adsorption come from entropy driven and enthalpy-driven. The Adsorption Kinetics of Water-soluble corrosion inhibitor in the Q235 carbon steel surface was studied by hydrogen evolution current decay curve method and colorimetric method, results showed that Water-soluble corrosion inhibitor formed a layer of protective film on the surface of carbon steel in a short time, and the film has good stability. Adsorption model analysis showed that the adsorption of water-soluble corrosion inhibitor in the carbon model comply with Langmuir adsorption. The standard free energy of adsorption are negative, indicating that water-soluble corrosion inhibitor can be spontaneously adsorbed on the surface of Q235 carbon steel.
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