Qiqing ZHANG
,
Lei REN and Lingrong LIU(Institute of Biomedical Engineering
,
Chinese Academy of Medical Sciences
,
Tianjin 300192
,
China)Chun WANG(CCCD
,
University of Utah
,
Salt Lake City
,
UT84112
,
USA)
材料科学技术（英文）
Naturally derived collagen protein was mixed thoroughly with medical grade poly (vinyl alcohol)(PVA) at the ratio of 90:10 (w/w) and was crosslinked by formaldehyde to form a homogeneous composite membrane. The buIk structure of the membrane was characterized ly means of Xray diffraction (XRD) and transmission electron microscoor (TEM). The membrane surface Structure was investigated using Fourier transform-infrared spectroscopy (attenuated totalrefraction) (FTIR-ATR), electron spectroscopy for chemical analysis (ESCA) and contact angle measurement. lt was found that collagen and PVA can remain Stable. This was supported by the fact that no sign of phase separation had been observed. The use of crosslinking agent can Substantially influence the Structure of the composite. It is suggested that this new compositedeserves further investigation and is potentially usable as a biomedical material.
关键词:
Corrosion
The corrosion products formed on carbon steel exposed to the Qinghai Salt Lake atmosphere for 12 months was studied using scanning electron microscopy (SEM), electron probe micro-analysis (EPMA), x-ray diffraction (XRD), infrared transmission spectroscopy (IRS), and electrochemical techniques. The rust was mainly composed of akagarteite (beta-FeOOH), iron hydroxychloride (Fe(8)[O,OH](16)Cl(1.3)), and a little lepidocrocite (gamma-FeOOH). Amorphous (delta-FeOOH was only on the downward surface, and the upward surface was corroded more severely than the downward surface. Cl. Mg, and Si foreign elements were rich in the rust. The rust on carbon steel decreased anodic dissolution and increased cathodic current. A low free corrosion potential of the rusted electrode and a very small value of rust resistance (R(R)) demonstrated that the rust was nonprotective in the Qinghai Salt Lake atmosphere.
关键词:
atmospheric corrosion;carbon steel;salt lake
Corrosion Science
The product formed oil weathering steel exposed to salt lake atmosphere for 12 months was investigated by X-ray diffraction (XRD), infrared transmission spectroscopy (IRS), scanning electron microscopy (SEM), electron probe micro analyzer (EPMA) and electrochemical techniques. The rust was mainly composed of beta-FeOOH, Fe(8)(O,OH)(16)Cl(1.3) and a little gamma-FeOOH. Amorphous delta-FeOOH was only oil skyward surface. The rust layer suppressed anodic reaction and facilitated the cathodic reaction. The very small value of rust resistance R(r) in this work indicated that the rust had poor protective ability. Cl element was rich in the whole rust layer and played an important role in accelerating the corrosion of weathering steel in salt lake atmosphere. (C) 2007 Elsevier Ltd. All rights reserved.
关键词:
weathering steel;atmospheric corrosion;salt lake;plain carbon-steel;low-alloy steels;industrial environments;corrosion;behavior;mechanism;marine;iron
Acta Physico-Chimica Sinica
The rust layers formed on upward and downward surfaces of carbon steel exposed to salt lake atmosphere for 25 months were investigated by scanning electron microscopy (SEM), electron probe micro analyzer (EPMA), X-ray diffraction (XRD), infrared transmission spectroscopy (IRS), and electrochemical techniques. The depths of rust layers on upward and downward surfaces were similar to each other. The corrosion products on the two surfaces were mainly composed of beta-FeOOH, Fe-8(O,OH)(16)Cl-13, and a little gamma-FeOOH. delta-FeOOH and Fe3O4 were only detected in outer part of the rust layers. The results of electrochemical analysis showed that the rust layer suppressed the corrosion of steel substrate and the corrosion resistance of rust layers increased with time.
关键词:
carbon steel;atmospheric corrosion;EPMA;EIS;atmospheric corrosion;weathering steel;mild-steel;iron;environments;surfaces;behavior
Chinese Science Bulletin
The rusts formed on carbon steel and weathering steel exposed in Qinghai Salt Lake atmosphere for 6 months were characterized by X-ray diffraction (XRD), infrared transmission spectroscopy (IRS), scanning electron microscopy (SEM), electron probe micro analyzer (EPMA) and electrochemical polarization techniques. The two kinds of steels showed the similar corrosion rate, corrosion product composition and electrochemical polarization behavior. Their rusts were mainly composed of beta-FeOOH, Fe(8)(O,OH)(16)Cl(1.3) and a little gamma-FeOOH. Cl(-) played an important role during the corrosion process of low-alloyed steels. The alloyed elements Cr, Ni and Cu in weathering steel were detected in the rusts; however, they showed no remarkable protective ability.
关键词:
atmospheric corrosion;carbon steel;weathering steel;XRD;EPMA;weathering steels;carbon-steel;rust;mechanism;corrosion;iron
Materials Chemistry and Physics
The corrosion behaviour of CortenA weathering steel has been investigated using a laboratory accelerated test that involved cyclic wet/dry conditions in Qinghai salt lake water diluted 30 times The characteristics of the rust layers on tested samples were observed by SEM and EPMA analyzed by IRS and XRD and studied by polarization and EIS measurements The weight loss was almost linear indicating that the rust layer had no retarding effect on the corrosion process The crystalline components of the rust layers consisted primarily of beta-FeOOH magnetite (Fe(3)O(4)) and gamma-FeOOH As the corrosion proceeded the amount of beta-FeOOH decreased while that of magnetite and gamma-FeOOH increased XRD EDAX and EPMA indicated that the complex corrosion products magnesioferrite (MgFe(2)O(4)) and iowaite (Mg(4)Fe(OH)(8)OCl 4H(2)O) probably existed in the rust layer in which case they will have had an important Influence on the protectiveness of the rust layer The results of electrochemical measurements showed that the rust layer exhibited high reduction reactivity which facilitated the corrosion of weathering steel in the wetting process The large rust capacitance and small rust resistance indicated that the rust layer had a loose and porous structure which provided poor protection (c) 2010 Elsevier B V All rights reserved
关键词:
Elements;Corrosion test;Electrochemical techniques;Electron probe;low-alloy steels;atmospheric corrosion;carbon-steel;electrochemical;impedance;room-temperature;rust layers;iron;mechanism;products;environment
LI Jing HUANG Kexiong WANG Zaoji LIU Jun Central South University of Technology
,
Changsha
,
ChinaGUO Chuntai Changchun Institute of Applied Chemistry
,
Academia Sinica
,
Changchun
,
China LI Jing Professor
,
Faculty of Metallurgical Physical Chemistry
,
Central South University of Technology
,
Changsha 410012
,
China
金属学报(英文版)
Interfacial tension between liquid Al and molten fluoride salt was determined using sessile drop method combined with X-ray radiograph.A computer program of curve-fitting for coordination of configuration of sessile drop was used in the picture processing of the sessile drop.Regressive equation were worked out to calculate the density of the molten salt.The in- fluence of mole ratio of NaF/AlF_3,content of Li_2CO_3 and rare-earth oxides in the molten salt on interfacial tension of Al-salt was discussed.The contact angles of liquid Al on the sur- face of graphite,graphitized carbon cathode and the graphite with coating of TiB_2 were de- termined.
关键词:
interfacial tension
,
null
,
null
,
null
HAO Hongqi SONG Yujiu Xi'an Jiaotong University
,
Xi'an
,
China Institute of Metallic Materials and Strength
,
Xi'an Jiaotong University
,
Xi'an
,
China
金属学报(英文版)
The corrosion fatigue propagation behaviour of high strength low alloy Cr-Ni and Si-Mn steels has been investigated in 3.5 %NaCl solution spryly at the frequencies of 0.1 and 5.5 Hz. It was shown that the fatigue crack initiation resistances of the two steels are significantly re- duced in salt spray;the fatigue crack growth rates of steels increase with the decrease of fre- quency and are much higher in salt spray than in air within low ΔK range.A critical stress in- tensity factor was observed for each steel and the crack growth stoppage will occur if the ΔK values are lower than it.It was found that the active dissolution makes great contribution to the fatigue crack growth within low ΔK range.
关键词:
salt spray
,
null
,
null
,
null
Corrosion Science
Taking into account the chemical stability and scaling features of metals, four electrochemical impedance models were proposed to represent their electrochemical impedance responses in molten-salt systems at the open-circuit potential. Electrochemical charge transfer for the non-active metals is the rate-limiting process. For the active metals, the transfer of ions in the scale and the diffusion of oxidants in melts become increasingly important as compared with the electrochemical process. When a non-protective scale forms on the metal surface, the impedance diagram may present the characteristics typical of a diffusion-controlled reaction. i.e.. a semi-circle at high frequency and a line at low frequency. When a protective scale forms on the metal surface, the Nyquist plot is composed of double capacitance loops, and the transfer of ions in the scale is rate limiting. An equivalent circuit of double layer capacitance in series with oxide capacitance can be used to represent this kind of impedance response. In the case of localized corrosion, the Nyquist plot also consists of double capacitance loops, which can be described by an equivalent circuit of double layer capacitance parallel to oxide capacitance. Impedance measurements of Pt. Ni3Al and FeAl intermetallics in molten-salt systems were conducted to verify the proposed impedance models. (C) 2001 Elsevier Science Ltd. All rights reserved.
关键词:
electrochemical impedance;molten-salt corrosion;Pt, Ni3Al, FeAl;electrode;ni
