The corrosion behave of 20 steel in the five typical soil (Dongzhou, Wanghua, Lishi, Lutian kuang and Gaoer mountain) of Fushun by indoor buried corrosion test and electrochemical test were studied. The research shows that annual corrosion rate of 20 steel different in five typical soil, from high to low is: Lishi， Lutian kuang， Wanghua， Dongzhou， Gaoer mountain, the most serious corrosion of the 20 steel in Lishi area soil, the annual corrosion rate is 0.105 9 mm/a, about 10 times as Gaoer mountain area. The electrochemical research shows the serious corrosion of 20 steel in Lishi and Lutian kuang soil,because the immerse hours of native rust film on the surface of 20 steel is slow, the rust film is loose, not compact, discontinuous and instability, and does not have protective function. On the contrary, a continuous, compact and stable rust film can be formed on the surface of 20 steel in Dongzhou, Wanghua and Gaoer mountain soil which is slightly corroded and has protective function. 

The thiourea was added in the electroless plating solution to analyze the influence of thiourea on the Ni-P coating deposition rate, surface morphology and porosity, etc.. The corrosion resistance was evaluated through polarization curves and electrochemical impedance spectroscopy. The results show that when 1 mg/L thiourea in the electroless plating solution was added, the deposition rate of coating accelerates and the corrosion rate increases. This is mainly reason after thiourea was added in the electroless plating solution, the porosity of coating increases, which promote the corrosive medium to seep deeply into the surface of the substrate resulting in increasing the number of corrosion micro cells and forming a corrosion cell of the large cathode(coating)-the small anode (substrate). The corrosion current density increases and the charge transfer resistance reduces. While thiourea was added more than 3 mg/L, the electroless plating solution is poisoned and unable to plating.

  he currently used methods for determining the thermodynamic equilibrium of the two phase mixed substances is to judge the equality of the coefficient of each component in two phases, and by this analysis each component mole fraction can be got at the equilibrium state. Introduced diffusion equation to describe various gas and liquid components from exposure to the stabilization process, established a mathematical model to describe the two-phase non-equilibrium diffusion process, meantime introduced a new algorithm to solve the mathematical model. Using this methods a real gas-liquid two-phase system was analyzed. The results compared with the experimental data proved the feasibility of the method, thus the non-equilibrium phase transition analysis of the issue provided a new analysis method.

Using volume translation method to improve the calculation of the accuracy of liquid density for the SRK state equation ,so has no influence on the gas -liquid balance. On the basis of SRK state equation and volume translation method and PR state equation, more accurate calculation results of the density of saturated liquid were obtained. And the results were compared with the measured data of different methods.The results show that the calculation results of saturated liquid density using volume translation method are more accurate than using the SRK state equation or PR state equation and improved the scope of the application of SRK state equation.

The passive behavior and electrochemical characterization of the passive films formed on X80 and X70 pipeline steels in 0.5 mol/L NaHCO ₃ solution were discussed by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and capacitance measurements. It is show that X80 and X70 pipeline steels present a wide passive anodic region (-0.16~0.90 V), the passive current density (ip) of X80 and X70 steels are 6.76 μA/cm ² and 18.38 μA/cm ², respectively. EIS results indicate that the surface of the passive film formed on X80 steel is much denser and uniformer than that of X70, and the result is also show by AFM. Mott-Schottky analyses displayed that the passive films on X80 and X70 pipeline steels in 0.5 mol/L NaHCO ₃ exhibit n-type semiconductive characters in the potential region of -0.20 V to 0.80 V. Compared with the passive film of X70 steel, the donor density is much lower and the width of space charge layer is thicker for the passive film of X80 steel, so the corrosion resistance of the latter is better.

The corrosion behavior of X70 steel in Yingtan acidic soil was studied by using polarization curve technique and electrochemical impedance spectroscopy (EIS) in 13%~40% water content. It is found that X70 steel corrosion rate is rised with the increasing of water content and reached a maximum value when the water content of soil is saturated, and samples is corroded selectively expanding roundly. Cathode reaction is oxygen reduction when water content is 13%, hydrogen ion then participated in with the water content increasing. Water content and pH both affect X70 steel electrochemical behaviors. Corrosion resisting property of X70 steel is bad in Yingtan acidic soil.