In seawater the influence of biofilms formation kinetics process on two types of passive metals open circuit potentials (EOCP) were studied. 1Cr18Ni9Ti and high Mo steel coupons were immersed in seawater for about 10 days and EOCP increased for about 200mV after about 1 day.Epifluorescence microscopy observation and EOCP data showed that during the initial bacteria adsorption period that EOCP changed greatly and in the following time EOCP increased slowly. The bacteria amounts on metal surface increased according to an exponential law and its adsorption kinetics at metal surface was proposed. The ennoblement of EOCP was similar to the bacteria number increasing: EOCP increased quickly during bacteria adsorption process and increased slowly after biofilms had formed.

A special autoclave was used to study corrosion behavior of 304L, 316L, 317L stainless steel and nickel based alloy( Incoloy800) in acetic acid solution.The results showed that temperature plays a critical role in corrosion resistance of stainless steel and nickel based alloy, their corrosion rates was increased with the increasing of temperature, and the corrosion resistance of stainless turned worse suddenly when the temperature increased to some value.Ni and Mo had different influence on corrosion resistance at various temperature. For increase in corrosion resistance of stainless, Ni is effective in acetic acid at low temperature, and Mo is effective in acetic acid at high temperature.

The dealloying mechanism of the duplex-phase Cu-20Zr cast alloy and sputtered Cu-20Zr film in hydrochloric acid solution was investigated using the electrochemical methods, chemical and surface analysis technique. Results showed the duplex-phase in cast Cu-20Zr alloy is composed by two phases, one is the Zr-rich Cu51Zr14 phase, the anothers is the eutectoid of the Cu and Cu51Zr14 phase. The rich-Zr Cu51Zr14 phase selectively dissolves owing to its more reactivity at the low anodic potential, which illustrates the dissolution mechanism of the Cu-20Zr alloy is decided by the stability of the microstructure.The study of the corrosion rules of sputtered Cu-20Zr film shows further that the dissolution process of each element is different at the different polarized potential. When the potential is lower than the redox of Cu/Cu2+ ，the dissolution of Zr atoms is the main process;when the potential is higher than redox of Cu/Cu2+, Zr and Cu atoms in the film simultaneously dissolve, and the dissolution rate of Cu atoms is higher than that of Zr atoms. Subsequently ,Cu ions react with Cl ioms in the electrolyte, and form the corrosion product of Cu (I) and Cu (II) complex compound. These corrosion products covered the surface of the film,retarded the dissolution of Cu atoms.Zr atoms still dissolve continually with increasing the potential.

The Electrochemical Characteristics of pitting of X70 Pipeline Steel in Phosphate Buffer Solution are studied in this paper. It is found that the effect of Cl- ions on pitting protection potential is neglectable. PO43- ions show strong inhibition on nucleation and the growth of pitting. Impurity and the surface grooves left by polishing result in the nucleation and the growth of metastable pitting. The nucleation frequency increases at first and then decreases with potential, while peak current increases continually. In the potential range of metastable pitting, the impedance of passive film keeps almost unchanged with potential. However, the impedance shows an obvious decrease when potential is above pitting potential Eb.

Ni-7.5Cr,、Ni-10.9Cr、Ni-12.4Cr composites were prepared by means of co-electrodeposition of Ni matrix with three kinds of Cr particles in average size of 21 nm,39 nm, and 2.4µm, respectively. Compared to the electrodeposited microparticles-dispered composite coating (EMCC), the electrodeposited nanoparticles-dispered nanocomposite coatings (ENNCs) exhibits more homogeneous distribution of Cr particles and the interparticle spacing is approximately two orders of magnitude lower. The ENNCs have a very low oxidation rate at 900℃, due to the rapid formation of a continuous and compact chromia scale, whereas the EMCC exhibits a very poor oxidation resistance, due to the formation of porous NiO scale. For the ENNCs, the finer the Cr particles codeposited, the better the oxidation performance. The particles size effect on the oxidation behaviour of electrodeposited Ni-Cr composites is also discussed.

The protection performance of four polymer/Dacromet composite systems, namely three solvent-borne polymers, polyurethane, alkyd primers and fluorinated polymer as well as a water-borne coating, styrene-acrylate latex, was studied with or without pretreatment by gamma-aminopropyltriethoxysilane (γ-APS) by electrochemical impedance spectra (EIS) in 3.5%NaCl solution. The results showed that the sequence of protective performance was: fluorinated polymer>styrene-acrylate latex>polyurethane>alkyd/Dacromet composite system due to the different hydrophobic Pretreaties of organic polymers and eistence of the dispersed microorganic particles in styrene-acrylate latex. Pretreatment with γ- APS on Dacromet illustrated a markedly enhanced anti-corrosion performance of the polyurethane and alkyd/Dacromet systems because of the presence of the silane film restrained the diffusion of corrosive particles. But it also suppressed the synergetic protective effect in styrene- acrylate latex system,which led to decrease anti- corrosion performance. Pretreatment presented no obvious influence on fluorinated polymer/ Dacromet system due to the good hydrophobic property of the polymer.

Modeling study of corrosion processes of unearthed bronze relics was preformed b y EQ3/6,a software package for geochemical modeling of aqueous system.It was rev ealed that:cuprite,malachite and tenorite are the three main kinds of copper-bea ring minerals which would be supersaturated when Cu concentration in the solutio n is high enough(higher than 0.0016 mol/L,0.0079 mol/L separately) under the stu dy conditions.Copper exists in the solution mainly as the species of CuCO3(aq) ,Cu2+ and CuOH+.The corresponding content of CuCO3(aq) would be decrea sed following the deposition of the copper-bearing minerals,nevertheless,Cu2 + and CuOH+ would be increased.The species of Cu and the saturation index of the copper-bearing minerals would be greatly affected by the Eh and pH va lues of the solution.Cuprite is supersaturated in the studied Eh and pH co nd ition(Eh=-0.2 V～0.7 V,pH=5～9.5).Malachite and tenorite are supersatura ted under the conditions Eh>0.2 V,pH>7,while chalcocite is supersaturated under the con d ition of pH<7 and Eh<0.2 V.Water-bronze interaction has been revealed that cuprite,malachite,tenorite,cerussite,cassiterite,copper,lead and tin would be f ormed in a sequence from the early stage to the later stage of the reaction.The simulation calculation also showed the different behavior between Cu and Zn.It h as demonstrated that Cu was leached off easily and the corresponding content in outer corrosion layer is lower than the interior layer,but Sn is just contrary. It is believed the corrosion processes of bronze could be divided into two stag es:at the first stage,cuprite,malachite and tenorite were formed;cassiterite ,cerussite and relic copper,lead and tin were formed in the second stage,which c an be found in the outer layer of bronze.The simulation result not only fixed th e natural corrosion products,but revealed the corrosion processes also which we could not understand by routine methods.So the geochemical modeling study can be used to simulate the bronze corrosion prod uct and its corrosion processes also.

The effects of Ni-P electroless plating on the corrosion resistance of sintered NdFeB magnets in 40 kHz frequency ultrasonic field were investigated. In the ultrasonic field,the deposition rate and the phosphorus content of plati ng layers were measured,the surface morphology were observed,and the corrosion resistance of Ni-P layers were studied.It was shown that with the increase of ultrasonic power,the deposition rate was increased,and the phosphorus content in plating layers was decreased.Subjected to the ultrasonic field,the electrol ess Ni-P layer got finer and more compact.With the ultrasonic field,the corros ion resistance of electroless Ni-P layers was improved effectively.

Surface of nanometer silicon dioxide and magnesium hydroxide was modified by Sol sperse17000 dispersing agent.Nano-concentrates were gotten by mixing modified na noparticles with resin through ball milling and supersonic wave,then flame retar dant nano-coatings with different content of nano-concentrates were prepared.Dis persion morphology and stability principle of nanoparticles were analyzed by the use of transmittance electron microscopy (TEM) and Fourier transform infrared s pectroscopy(FT-IR).Morphology,molecule structure,water transport behavior and th ermal degradation of the flame retardant coatings were studied by use of SEM,FT- IR,curve of weight loss,DTA.It is indicated that 4% nano-concentrates can enhanc e water resistance and do not harm thermal degradation and flame retardant prope rty.

By the sol-gel method and spin-coating process,the nano TiO2-SnO2 composite films have been prepared on the surface of the indi um-tin oxide(ITO)glass and 316L stainless steel.The morphology and crystalline s tructure have been characterized by AFM and XRD.The anticorrosion property of th e composite coatings has been studied under dark condition by electrochemical me thods.Similarly,the performance of photogenerated cathodic protection of the com posite coatings has been measured in 0.5 mol/L NaCl solution(pH=46)by combinin g photoelectrochemical system with corrosion electrochemical system under UV illu mination.The results show that in dark the nano TiO2-SnO2 composite films ha ve a poorer anticorrosion property than that of the nano TiO2 coatings.Under U V illumination condition the composite films as a photoanode provide a cathodic protection for 316L,and when the UV light is shut off,its photogenerated potenti al can remain a cathodic protection of metal for 6 hours.The mechanism of the ph otogenerated cathodic protection has also been studied by electrochemical impeda nce spectra.

Electrochemical impedance spectroscopy (EIS) was co upled with differential scanning calorimetry (DSC) and X-ray photoelectron spect roscopy (XPS) methods to investigate the effects of nano-Ti particle on the corr osion resistance of an epoxy coating on carbon steel.Four systems were studied:a clear coat and three pigmented coatings (with 0.1%,05%,1% nano-Ti).Impedance measurements showed that nano-Ti particle could improve the corrosion resistance of the coating;and the optimal addition is 0.5% (mass%).The results obtained by D SC and XPS showed that the nano-Ti particle enhanced interactions with epoxy res in.Addition the nano-Ti particles into epoxy resin can act two opposite effects: the beneficial effect is attributed to a chemical reaction between the nano-Ti powder and the epoxy resin,which improves the barrier effectiveness of the coati ng; this outweighs the harmful effect of an increase in the number of pores in t he coating.

Electrochemical impedance spectroscopy (EIS) was co upled with differential scanning calorimetry (DSC) and X-ray photoelectron spect roscopy (XPS) methods to investigate the effects of nano-Ti particle on the corr osion resistance of an epoxy coating on carbon steel.Four systems were studied:a clear coat and three pigmented coatings (with 0.1%,05%,1% nano-Ti).Impedance measurements showed that nano-Ti particle could improve the corrosion resistance of the coating;and the optimal addition is 0.5% (mass%).The results obtained by D SC and XPS showed that the nano-Ti particle enhanced interactions with epoxy res in.Addition the nano-Ti particles into epoxy resin can act two opposite effects: the beneficial effect is attributed to a chemical reaction between the nano-Ti powder and the epoxy resin,which improves the barrier effectiveness of the coati ng; this outweighs the harmful effect of an increase in the number of pores in t he coating.

2-amino-5-propyl-1,3,4-thiodiazole and 2-amino-5 -isopropyl-1,3,4-thiodiazole inhibition behavior on H62 copper in 3%NaHCO3 solution is investigated by means of weight loss and electrochemical methods.It is shown that two inhibitors have good inhibition performance for copper in 3%Na HCO3 solution.And 2-amino-5-propyl-1,3,4-thiodiazole’s inhibition efficiency is better than 2-amino-5-isopropyl-1,3,4-thiodiazole’s.The adsorption processes are exothermic reaction and belong to the chemical adsorptions.The Langmuir iso therm is followed.