A state-of-art design of corrosion inhibition knowledge bank is proposed with intentions of easier information sharing and knowledge distribution in order to minimize effort of new inhibitor development. While designing such as knowledge bank, several key design objectives, like simplified operation, expandability, flexibility and so on, have been kept in mind. Each of those objectives has been rationed in detail. First of all, a dedicated discussion of database schema as the core component of the knowledge bank is done in order to clarify its impact on overall system performance. The detail of arrangement of tables and composition of each table are addressed and illustrated. Three architectures of inhibitor knowledge bank are proposed to meet the various usage environments. Then, focuses are laid on the information retrieving, data mining and knowledge forming one by one since those are assumed to be "must-have" functions. The issues of system configuration and integration are addressed; and the approaches to these issues are discussed including pros and cons. The overall picture of inhibitor knowledge bank system is outlined at the end.
This work presents a reference implementation of corrosion inhibitor knowledge bank (YFIKB) based on the integrated database architecture proposed in the first issue of this series. YFIKB implementation takes Microsoft Access as data management system for sake of simplicity and easy operation. The data source and integration approaches are introduced at first. The emphasis is laid on the function demonstration of information access and knowledge distribution. In YFIKB, more than 15 dedicated queries, categorized into 3 groups, are built in for faster information retrieving and knowledge distribution. Additionally, a customable mechanism is also built to allow the seasoned user to locate information quickly and precisely through graphical user interface. Information publishing and report generation is also highlighted. Data input and categorization, as tedious tasks, are facilitated by dynamic data parsing and assembling in YFIKB. The possible improvement on YFIKB is discussed at the end.
Four kinds of imidazoline inhibitors with different hydrophobic group i.e. 2-heptadecyl-aminoethyl-imidazoline (IM-17), 2-undecyl-aminoethyl-imidazoline (IM-11), 2-nonyl-aminoethyl-imidazoline (IM-9), 2-butyl-aminoethyl-imidazoline (IM-4) had been synthesized and characterized by IR and UV spectra. The inhibition performance of these imidazoline inhibitors for CO2 corrosion of N80 in 3% NaCl solution was investigated through linear polarization resistance, polarization curve and electrochemical impedance spectroscopy under static and flow conditions. The results showed that the inhibition efficiency under static condition decreased in the order of IM-9>IM-4>IM-11>IM-17, i.e. the inhibition efficiency was related with both the solubility and the length of carbon chain of hydrophobic group of imidazolines. In contrast, the inhibition efficiency at 5 m/s decreased in the order of IM-9>IM-1>IM-17>IM-4, and solution flow (5 m/s) dramatically worsened the inhibition performance of imidazolines.
The corrosion behavior of Cu/LDPE composites in the simulated uterine solution (SUS) was monitored using electrochemical impedance spectroscopy (EIS). According to the EIS characteristics, the equivalent circuits were established. The electrochemical parameters of the composites and its interface were obtained, including double layer capacitance, charge transfer resistance, Warburg impedance and so on. By comparing the change of interface stats of two composites with time, the influence of copper particles on composites corrsion was discussed. The results indicated that the corrosion rate of nanocomposite is lower than that of microcomposite and there is less deposit on the surface of the nanocomposite. The nanocomposite is a superior material to make new type intrauterine device.
In order to research the corrosion resistance of SUS304 stainless steels with pack aluminized process, the corrosion resistance tests in 0.33 mol/L FeCl3+0.05 mol/L HCl, the oxidation tests at 1000 ℃, and the corrosion resistance tests in deposition of alkali-chloride and sulphate at 500 ℃ were conducted. The corrosion resistance was comprehensively evaluated by weight loss method and electrochemical tests etc. The experimental results indicated that aluminized layer of SUS304ss was dense, and the thickness was 50 μm; the pitting corrosion resistance of aluminized SUS304ss was better than that of unaluminized one; the oxidation properties of aluminized SUS304ss increased 5 times at 1000 ℃; the corrosion resistance of aluminized SUS304 in deposition of alkali-chloride and sulphate increased about 20 times at 500 ℃; the corrosion potential of aluminized SUS304 was higher than that of unaluminized one, which had better corrosion resistance.
The steam oxidation of T91 steel exposed to the Ar+H2O mixed atmosphere at 650 ℃ was investigated. The formed scales were successively composed of Fe2O3，Fe3O4 and (Fe,Cr)3O4 from the outer surface. The steam oxidation kinetics of T91 steel followed the parabolic law at the atmosphere with 5% steam and partially followed the parabolic law at the atmosphere with 7% and 10% steam. Increasing the steam content remarkably accelerated the steam oxidation rate of T91 steel. It was observed that the multilayer oxidation scales formed on the surface of T91 steel after exposed to the mixed atmosphere with 5\%、7% and 10% steam (vol.%) for 10 h. The effect of the steam contents in the mixed atmosphere on the oxidation mechanism of T91 steel was discussed.
Stress corrosion cracking (SCC) behavior of X70 pipeline steel in simulated Ku$^\prime$erle soil solution at different applied potentials was investigated using slow strain rate testing (SSRT). Morphology of X70 pipeline steel fracture surface at different applied potentials was observed by scanning electron microscope (SEM). The results showed that X70 pipeline steel was susceptible to SCC in simulated solutions. It was found that low potentials applied increased susceptibility to SCC at open circuit potential (OCP). The fracture mechanism followed anodic dissolution mechanism of SCC. The precipitation of hydrogen increased hydrogen diffusion into the metal, hence increased susceptibility to SCC under higher cathode potential in simulated solution. The fracture followed hydrogen induced cracking mechanism.
With the presence of tetramethylammonium chloride the aluminum coatings were obtained on iron substrate in eutectic chloride molten salt by D.C. plating. Scanning electron microscope(SEM), X-ray diffraction(XRD) and polarization curves were used to test the surface morphology, microstructure and corrosion resistance of the obtained coatings. Effect of tetramethylammonium(TMA) on Al deposition mechanism in the molten salt was investigated by cyclic voltammogram. The results showed that optimum currency efficiency of 93.6 % was obtained when mass fraction of TMA reached to 1.0%. Aluminum coatings obtained in eutectic chloride molten salt is acicular and has (200) preferred orientation face-centered cubic structure, while that obtained in TMA added molten salt is irregular. Pitting corrosion potential of aluminum coating was enhanced 0.12 V and the extent of irreversibility was enlarged by adding TMA.
Electrochemical impedance spectroscopy (EIS) was employed to investigate the corrosion regulations of nano-SiO2 modified epoxy coatings on carbon steel in 3.5 mass% NaCl solution, coupled with capacitance and gravimetric methods. The water uptake behavior of modified coatings was analysed. Four systems were studied, which are clear coating and three pigmented coatings (with 1%,2%,3% mass percentage nano-SiO2). The EIS results showed that nano-SiO2 particle could improve the anti-corrosion performance of the coatings, and the optimal additions is 2%. The results obtained by capacitance and gravimetric methods showed that the diffusion process of water through epoxy coatings with different PVC(pigment volume concentration) followed the second Fick diffusion law in the initial period. Adding the nano-SiO2 into epoxy coatings can act effectively. The positive one is attributed to the reaction between nano powder and epoxy resin, which improve the barrier effectiveness of coatings. The negative one is to increase the number of pores in the coatings when the adding amount is beyond the critical pigment volume concentration.
Acrylic polyurethane varnish coatings were exposed to artificial weathering test (UVB radiation/condensation) for different periods of time. The changes of properties and barrier protection property were monitored by adhesion tester, glossmeter, spectrophotometer, Fourier transform infrared spectroscopy (FTIR) and electrochemical impedance spectroscopy (EIS). The results showed that the adhesion strength and low frequency impedance |Z| f at a fixed frequency from EIS spectra decreased, while gloss loss and yellow index increased with increasing aging time. FTIR results showed that the increase of adhesion strength or |Z|f at 12 days exposure may be attributed to the re-association of scission molecular segments. The low frequency impedance of intact coatings for different exposure time correlated with other physical and chemical properties.
The effects of simulated nitric acid rain in different pH value on X70 steel in acidic soil were studied by means of polarization curves、electrochemical impedance spectroscopy(eis)、x-ray diffraction(xrd)、scanning electron microscopy(sem) etc. The results revealed that simulated acid rain could heavily increase the corrosion rate of X70 buried; The results of X-ray showed that corrosion products mainly consist of Fe2O3, SiO2; The results of SEM showed that with the increasing of pH value surface roughness was falling and quantities of microspores decreasing.
Six different 2-D physical models for cathodic protection of copper by medium carbon steel as sacrificial anode in seawater are built in this paper. Weak form of Laplace equation was deduced to make finite element method (FEM) numerical calculation convenient. Then, potential distribution of various physical models was computed by FEM, and followed by experimental measurements for validation. The results show clearly that potential distribution of the cathodic protection system could be well simulated by the 2-D FEM solution. The distance of the galvanic couples is not a key factor influencing potential distribution in small range. Typical simulation data (along X-axis and Y-axis) of different models are consistent with the experimentally measured results. Therefore, it should be feasible to cathodically protect copper with medium carbon steel as sacrificial anode, and FEM could afford well a basis for cathodic protection design.
Based upon the principal component analysis, the correlation between the weathering conditions was investigated. With the correlation matrix, the primary factors of weathering condition were selected. And by the component matrix from component analysis, the 13 cities were classified to six groups and the classification was consistent with the prime climate type of China. According to the classification, we can supervise the aging experiment under nature weathering and investigate the effects of the weathering on the properties of materials.
The recent progress in the atmospheric corrosion of carbon steel and weathering steel is reviewed. The corrosion behavior of the above two kinds of steels is compared. The similarities in corrosion process, corrosion products, and effect factors of the two steels are analyzed. The differences in the corrosion rate and rust microstructure of the two steels are discussed.
