3PE防腐蚀层联合阴极保护对管道的保护效果

采用阴极保护联合3PE防腐蚀层的方法对埋地钢质管道进行了防护。试验模拟了管道3PE防腐蚀层底漆存在、金属基体暴露、金属暴露孔处未与土壤介质接触及与土壤介质完全接触的不同情况,探讨了阴极电流与通电电位之间的关系,研究了通/断电位的负移对试样3PE防腐蚀蚀层阴极剥离的影响。结果表明,试样阴极保护电流的变化与管道3PE防腐蚀层的缺陷存在、土壤接触方式、通电电位密切相关。通/断电电位正于-0.85V(CSE)时,难以阻止试样发生腐蚀,通/断电位过度负移将造成3PE防腐蚀层的阴极剥离,使3PE防腐蚀层提前失效。     

耐火粉料对金属型涂料性能的影响

研究了硅藻土、莫来石、滑石粉、白刚玉4种不同耐火粉料对金属型涂料悬浮率、强度、条件粘度、发气量、触变性的影响。实验结果表明:硅藻土是影响涂料悬浮率、发气量和强度的最显著因素;莫来石可以有效提高涂料的悬浮率及粘度;滑石粉是影响涂料条件粘度的最显著因素;不同的粉料组成对涂料的流体形态及条件粘度影响较大。     

用直流电位梯度法测量埋地管道防护层缺陷位置的模拟试验

介绍了埋地管道防护层缺陷电位梯度检测技术。用盐溶液、蒸馏水和自来水的混合液模拟土壤介质,通过改变管道防护层缺陷大小,改变环境电阻率和保护电流,试验证明了电位梯度检测技术能够比较准确地检测出管道防腐层缺陷的位置,并得到了管道埋深和地表电位梯度的关系。     

地下管道防护层缺陷检测技术研究与应用

埋地钢制管道腐蚀检测及防护是相关行业工作中的重要内容.本文介绍了国内外管道防腐层缺陷检测的几种检测方法,包括标准管地电位法、近间距电位法、电流梯度法、直流电位梯度法等,分析了各种管道检测技术的原理和优缺点.重点说明了直流电位梯度法在确定防腐层缺陷位置方面的优越性.     

Improving the Anticorrosion Characteristics of Polymer Coatings in the Case of Their Modification with Compositions Based on Organosilanes

Protection of Metals and Physical Chemistry of Surfaces - The effect of a series of organosilanes and their mixtures with corrosion inhibitors on the anticorrosion properties of polymer and paint...     

一种埋地管道剥离涂层下金属腐蚀电化学试验装置

针对防腐蚀层剥离管道在土壤环境中的腐蚀问题,在总结现有国内外相关研究试验装置与研究方法的基础上,设计组装了一套新的电化学试验装置。该装置在具有制造简单、方便、可重复试验的同时,能够较好地模拟埋地管道涂层破损、剥离状态下金属基体的腐蚀环境。测试性试验结果表明,该试验装置便于电化学阻抗谱、极化曲线等电化学测量信号的测试。     

玻璃鳞片对环氧涂料抗阴极剥离性能的影响

测试了玻璃鳞片的添加对环氧涂料抗阴极剥离性能的影响。发现,添加玻璃鳞片的环氧涂料具有较好的抗阴极剥离性能。对其机理进行了一定的探讨。     

Parametric Study of Metal/Polymer Multilayer Coatings for Temperature Wrinkling Prediction

This article presents an analytic model for the prediction of wrinkling occurring in metal/polymer coatings under particular conditions. Owing to different thermal expansion coefficients (TECs) of the substrate and the different coating layers, temperature variation can induce a compressive stress in the coating. The wrinkling is the material response to the instability caused by this compressive stress. In this study, a reference case was selected: a 0.27-mm-thick steel sheet with a 5-μm-thick polymer layer and, on top of it, a thin aluminum film of 50 nm in thickness. For this reference case, it was observed and predicted by the model that an increase in temperature yielded to the wrinkling of the thin aluminum film. The geometry of the multilayer coating and the properties of the constituent materials are factors able to promote or prevent the wrinkle. To better understand and predict their effects, a sensitivity analysis was carried out with the proposed analytic model. A special attention was devoted to the temperature when wrinkling occurs. The key parameters having a significant influence on the wrinkling temperature were identified. It is concluded that the elastic modulus of the thin aluminum film and that of the polymer, the TEC of the thin film, and the initial stress induced during the processing of the multilayer system all had a significant influence on the wrinkling temperature.     

Effect of Coil Current on the Properties of Hydrogenated DLC Coatings Fabricated by Filtered Cathodic Vacuum Arc Technique

We successfully prepared hydrogenated DLC (a-C:H) with a thickness higher than 25 μm on stainless steel using a filtered cathode vacuum arc (FCVA) technique. The structural and mechanical properties of DLC were systematically analyzed using different methods such as x-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, Vickers hardness, nanohardness, and friction and wear tests. The effect of coil current on the arc voltage, ion current, and mechanical properties of resultant films was systematically investigated. The novelty of this study is the fabrication of DLC with Vickers hardness higher than 1500 HV, in the meanwhile with the thickness higher than 30 μm through varying the coil current with FCVA technique. The results indicated that the ion current, deposition rate, friction coefficient, and Vickers hardness of DLC were significantly affected by the magnetic field inside the filtered duct.     

EIS Studies of Protective Polymer Coatings on Low-Carbon Steel in Sulfuric Acid

Protection of Metals and Physical Chemistry of Surfaces - Abstract—The electrochemical properties of protective epoxy polymer coatings with different designs are studied with electrochemical...     

Properties of Induction Plasma Sprayed Iron Based Nanostructured Alloy Coatings for Metal Based Thermal Barrier Coatings

Metal-based thermal barrier coatings (MBTBCs) have been produced using high frequency induction plasma spraying (IPS) of iron-based nanostructured alloy powders. The study of MBTBCs has been initiated to challenge issues associated with current TBC materials such as difficult prediction of their “in-service” lifetime. Reliability of TBCs is an important aspect besides the economical consideration. Therefore, the study of MBTBCs, which should posses higher toughness than the current TBC materials, has been initiated to challenge the mechanical problems of ceramic-based TBCs (CBTBCs) to create a new generation of TBCs. The thermal diffusivity (TD) (α) properties of the MBTBCs were measured using a laser flash method, and density (ρ) and specific heat (C _p) of the MBTBCs were also measured for their thermal conductivity (k) calculation (k = αρ C _p).     

Model Investigation of the Peculiarities of the Corrosion and Cathodic Protection of Steel in the Insulation Defects on Underground Steel Pipelines

The new data of model investigations on cathodic passivation, nature of galvanic macrocells, and the dimensional effects in the defects of insulation on underground pipelines are analyzed. Partially revising some conventional concepts concerning the mechanism of the corrosion and cathodic protection of steel in soils is advisable.     

The Effect of a Metal Surface on the Elasticity of Polymer Films

Protection of Metals and Physical Chemistry of Surfaces - The influence of the nature of the surface on the elastic properties of acrylic polymers with different glass-transition temperatures...     

海泡石对消失模涂料性能的影响

以高铝粉为耐火骨料,以海泡石和CMC作为悬浮剂,研究了一种适用球墨铸铁铸件的水基消失模涂料,分析了各原料加入量对涂料性能的影响。结果显示:增加海泡石的量能提升涂料悬浮性和涂层强度;磷酸二氢铝能提高涂层强度,但会降低涂料透气性;珍珠岩能提高涂料透气性。当海泡石的量为10%,磷酸二氢铝为4%,珍珠岩为12%时,各原料能有最佳的交互作用。     

Al含量对电弧离子镀共沉积Ti1-xAlxN涂层性能的影响

利用扫描电镜、X射线衍射仪、显微硬度计、划痕仪、磨损实验仪等,研究了不同铝含量的Ti1-xAlxN涂层性能.结果表明：当铝含量约为52%时,经涂层处理试样的显微硬度、摩擦磨损性能都得到了很大的提高,能达到使用钛铝合金靶离子镀Ti1-xAlxN涂层的相应性能,而从经济性来说,利用独立钛、铝靶比钛铝合金靶制备Ti1-AlxN涂层的成本要低得多,从而具有降低生产成本,提高生产效益的优势.     

城镇燃气埋地钢质管道牺牲阳极阴极保护的设计

在明确了阴极保护的管道条件前提下,文章简述了埋地钢制管道牺牲阳极阴极保护基本原理,确定了应采用的阳极材料;给出了规范要求和设计参数、以及镁阳极接地电阻的简化计算公式;明确了不宜使用钢套管及对水泥套管内管道采取的保护措施;给出了阳极地床填包料的组分。     

复合化学镀层对金刚石-金属复合材料性能的影响

本文研究了化学镀Ni Cr P和Ni W P对金刚石 金属复合材料性能的影响。结果发现 ,在Co基和Ni 青铜基复合材料中 ,Ni Cr P和Ni W P镀层均可以起到提高复合材料抗弯强度的作用。相对而言 ,Ni Cr P效果更好 ,这与Cr对金刚石的化学活性较高 ,Ni Cr P熔点较低以及金刚石、镀层、结合剂三者之间的界面反应等有关。     

Effect of AlN Thickness on Structure and Properties of AlN/Al Dual Protective Coatings on NdFeB by DC Magnetron Sputtering

In order to improve the corrosion resistance of NdFeB,AlN/Al dual protective coatings were prepared by DC magnetron sputtering in a home-made industrial apparatus.The inner Al layer with an excellent toughness was deposited onto NdFeB substrate firstly.And then the outmost AlN layer with a higher hardness was prepared with the nitrogen/argon mixture gas of the nitrogen partial pressure at 50%of the total pressure of 0.5 Pa and depositing time of 30,50 and 70 min,respectively.The denser outmost AlN layer was formed on the inner Al crystal layer.There is an occurrence of the interfacial reaction and metallurgy bonding in the interface layer between the coatings and NdFeB substrate.It has been found that the thickness of outmost AlN layer has a significant impact on corrosion resistance.For 50 min to deposit outmost AlN layer,AlN/Al coated NdFeB has the best corrosion resistance.     

Effect of Powder Characteristics on Properties of Warm-Sprayed WC-Co Coatings

In high-velocity oxy-fuel (HVOF) spraying of WC-Co coatings, the decomposition and decarburization of WC during deposition are responsible for their much lower toughness compared with a sintered bulk WC-Co. In a previous study, Warm Spray (WS) process, which is capable to control the flame temperature used to propel powder particles, was successfully applied in an attempt to suppress such detrimental reactions by keeping particles’ temperature lower than their melting point. The coatings deposited by WS process showed no or little formation of W₂C and η phases and demonstrated moderately improved fracture properties. However, there is still a gap in fracture toughness between WS coatings and the corresponding sintered bulk. In order to optimize the properties of the WS coatings, the effect of original powder sizes were investigated. Microstructural characterization and phase analysis were carried out on deposited coatings by SEM and XRD. The results show that the feedstock powder size has substantial effects on the properties of the coatings, i.e., the smaller powder showed improved properties.