浅议锚杆的腐蚀问题

鉴于其在应用中的优越性，锚杆在实际工程中得到了越来越广泛的应用。但人们往往忽视了锚杆的腐蚀问题，使其成为工程中的“定时炸弹”。文章主要从锚杆腐蚀的原理、影响因素和防护措施等三个方面论述了锚杆的腐蚀问题。     

In vitro corrosion of Mg–1.21Li –1.12Ca –1Y alloy

The influence of the microstructure on mechanical properties and corrosion behavior of the Mg–1.21Li–1.12Ca–1Y alloy was investigated using OM, SEM, XRD, EPMA, EDS, tensile tests and corrosion measurements. The results demonstrated that the microstructure of the Mg–1.21Li–1.12Ca–1Y alloy was characterized by α-Mg substrate and intermetallic compounds Mg2 Ca and Mg24Y5. Most of the fine Mg2 Ca particles for the as-cast alloy were distributed along the grain boundaries, while for the as-extruded along the extrusion direction. The Mg24Y5 particles with a larger size than the Mg2 Ca particles were positioned inside the grains. The mechanical properties of Mg–1.21Li–1.12Ca–1Y alloy were improved by the grain refinement and dispersion strengthening. Corrosion pits initiated at the α-Mg matrix neighboring the Mg2 Ca particles and subsequently the alloy exhibited general corrosion and filiform corrosion as the corrosion product layer of Mg(OH)2and Mg CO3 became compact and thick.     

Surface characteristics and corrosion resistance of biodegradable magnesium alloy ZK60 modifi ed by Fe ion implantati on and deposition

The ZK60 magnesium alloy has been modified by Fe ion implantation and deposition with a metal vapor vacuum arc plasma source. The surface morphology, phase constituent and elemental distribution are determined by scanning electron microscopy, transmission electron microscopy, X-ray diffractometer and Auger electron spectroscopy. The results show that Fe thin film is deposited on ZK60 alloy and the corresponding thickness increases from 2.73 μm to 6.36 μm with increasing deposition time. A transition layer mainly composed of Mg, Fe and O elements is formed between Fe thin film and ZK60 substrate. The potentiodynamic polarization tests reveal that a high corrosion potential and a low corrosion current density are detected for the Fe deposited ZK60 alloy, indicating the improvement of corrosion resistance. The tensile deformation test indicates that the Fe deposited film on the ZK60 substrate can sustain 1% tensile strain without any cracks.     

Insight into the covalent grafting of organic films onto carbon steel surfaces for protection

The novel use of p-nitrophenyldiazonium tetrafluoroborate salt(GG salt)as a protectant that is electrochemically grafted onto carbon steel has been investigated in0.05 mol L-1H2SO4and 5 wt%NaCl solutions using various corrosion monitoring techniques,such as electrochemical impedance spectroscopy,potentiodynamic polarisation,infrared spectra and scanning electron microscopy measurements.The electrochemical study reveals that this compound is a mixed inhibitor that predominantly controls the cathodic reaction.The surface-grafted film decreases the double-layer capacitance and obviously increases the charge transfer resistance relative to a bare carbon electrode.The values of inhibition effect remain nearly unchanged with an increase in temperature range of 298–318 K.The aryl diazonium is covalently bonded on the steel surface,causing a slight decrease in the apparent activation energy.Overall,the surface-grafted films exhibit excellent inhibition performance in acid and saline solutions within the studied temperature range.     

钢丝绳铝压套的腐蚀分析及防护

钢丝绳铝压套压制索具由于其制作简单,节省钢丝绳材料,生产效率高,广泛应用于各行各业.但随着其应用范围的扩大,钢丝绳铝压套索具的铝压套腐蚀开裂问题逐渐曝露出来,该文针对在工程中遇到的钢丝绳铝压套索具腐蚀开裂情况进行了深入的分析,并提出防护建设.     

提高地下管道防腐层破损点定位精度

文章叙述了地下管道防腐层破损点检测的意义,分析了地下管道防腐层破损点上方地表电位分布的特点,定位方法及干扰排除技术,难点检测技术与标志技术,并就开挖验证方法进行了叙述。     

超声波在石油钻杆损伤检测中的应用

腐蚀疲劳与应力损伤是石油钻杆损坏的最主要原因,钻杆损伤检测可以有效地预防和减少钻具因失效而引起的质量事故。阐述了石油钻杆健康监测中损伤识别的关键问题,介绍基于超声波的损伤定位定量方法。根据其基本结构和受力特点,以石油钻井中常用5〞钻杆为对象进行损伤研究,用超声波纵波直接接触法检测钻杆,并对探伤结果进行分析和应用。结果表明,超声波可对已定位损伤的石油钻杆的损伤进行定量分析,通过实例验证了其对结构损伤诊断的有效性。     

工业锅炉防腐的正确干法保养

探讨停炉锅炉的腐蚀原理、干性防腐保养方法的优势及具体正确操作,包括锅炉内部及外部的保养重点及保养措施,为停炉锅炉的保养提供依据。     

Biodegradable zinc-iron alloys: Complex study of corrosion behavior,mechanical properties and hemocompatibility

Zn-Fe alloys have been extensively investigated in this study with a view to their application as biodegradable bone implants. Biogenic element zinc is a very appropriate metal because of the ideal degradation rate compared to those of Mg and Fe. Studied alloys were made by compressing metallic powders in a content ratio of 100% Zn,Zn-1% Fe, Zn-2% Fe, Zn-5% Fe and Zn-10% Fe and sintering at 350°C for 1 h. Prepared samples were examined by optical microscopy, SEM and XRD. Corrosion behavior, mechanical testing and hemocompatibility were observed subsequently. The electrochemical performance of such materials was studied in the simulated body fluids. The enhanced corrosion rate was observed for all samples after iron addition due to the micro-galvanic effect between the pure Zn and Zn_(11)Fe intermetallic phase. The corrosion rate of the Zn-5% Fe alloyed sample was more than 20-times higher(2.89 mmpy) compared to the pure Zn. However, alloying with more than 5 wt %of iron diminished the mechanical performance of the material. Therefore, the performed mechanical and hemocompatibility tests showed acceptable biocompatibility of zinc and Zn-1% Fe and Zn-2% Fe samples.     

Corrosion behavior of Ni–P/nano-TiC composite coating prepared in electroless baths containing different types of surfactant

In current research, in order to enhance the incorporation of nano-sized TiC particles into electroless Ni–P (EN) coating, different types of surfactant (cationic, anionic, and polymeric) were added to the plating bath. The effects of addition of the surfactants on surface morphology, deposition rate, TiC and P contents of the prepared coatings were investigated. The surface morphology was evaluated by scanning electron microscopy (SEM). It was demonstrated that in the presence of the anionic, polymeric and somehow cationic surfactants, TiC nano-particles were embedded in the matrix which influenced the surface morphology. The effect of surfactant types on the corrosion properties of Ni–P/TiC coated steel was also studied. Corrosion behavior of the coated steel was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) which affected by the incorporation of TiC particles into the Ni–P matrix. The level of corrosion resistance improvement depended largely on the phosphorous and TiC concentration of the applied coating.