环氧/聚脲复合涂层结构在长输管道上应用的可行性

通过对现行几种管道防腐蚀涂料技术标准的对比分析,着重对聚脲和环氧粉末涂层的耐阴极剥离性能进行了展示和比较,提出了环氧粉末涂层作为底层,聚脲涂料作为面层的新的埋地管道涂层结构,并对这种结构的抗低温弯曲、抗冲击性、抗划伤性、热水附着力、层间附着力,抗阴极剥离性能进行了试验,提出了这种新结构在长输管道上应用的可能性。     

管道3PE涂层的阴极剥离性能研究

分析探讨了管道3PE涂层阴极剥离的机理和产生条件,试验研究了不同温度、时间下极化电位等因素对3PE涂层等的阴极剥离性能的影响规律.结果表明,在一定的条件下,极化电位的变化对3PE涂层的阴极剥离性能影响不大。     

固化温度对补口环氧底漆固化行为及性能的影响

采用差示扫描量热法(DSC)研究了不同温度下环氧底漆的固化过程,以及固化温度对固化后涂层拉拔附着力和耐阴极剥离性能的影响。并利用电化学阻抗谱(EIS)评价了涂层的耐水渗透性。结果表明,环氧底漆的固化受温度影响较大。随着固化温度升高,固化时间减少,涂层的拉拔附着力、耐阴极剥离性能有所下降,固化温度对涂层耐水渗透性影响较小。     

钢质管道熔结环氧粉末涂层拉拔法附着力评价研究

采用拉拔法对不同浸泡温度、浸泡时间的熔结环氧粉末涂层进行附着力性能测试,并与撬剥评级法进行比对。结果表明:拉拔法评价涂层附着力具有直观、量化、可反映涂层附着力变化趋势的优点;FBE拉拔法附着力评价测试条件为:Tg≤115℃的FBE涂层:浸泡温度为80℃,浸泡时间28d,Tg115℃的FBE涂层:浸泡温度为95℃,浸泡时间28d;附着力性能评价指标为≥20MPa。     

埋地管道防腐蚀层阴极剥离影响因素

防腐蚀层和阴极保护的联合防护,是目前防止埋地油气管道受到腐蚀破环的最佳保护方法。但在一定条件下,阴极保护会使涂层与基材之间发生阴极剥离,造成涂层失效,导致能量和金属材料的损失,同时加大了阴极保护工程设计及维护过程中的困难和不确定性。因此,当防腐蚀层与阴极保护共同使用时,防腐蚀层抗阴极剥离的性能就显得尤为重要。本文总结了防腐蚀层性能和阴极保护电位等因素对埋地管道防腐蚀层阴极剥离的发生和发展的影响,介绍了国内外对管道防腐蚀层阴极剥离的研究现状。     

在阴极保护／涂层体系中的涂层质量评价——加速试验和长期浸泡试验结果的比较

对于海水中的钢结构采用阴极保护和涂层相结合防腐措施是人所共知的。涂层在这种环境下，有可能失去附着力，如阴极剥离。本文对阴极保护／涂层体系中的涂层损坏情况做了调查研究。按照ASTM G8和BS3900F10部分试验方法对6种不同的涂层体系进行了阴极剥离加速试验。把涂层试样浸泡在室温下的天然海水中，采用铝阳极进行阴极保护，本试验测量了历时4年，记录了涂层损坏时的阴极电流需求、随机鼓泡和剥离程度。调查表明新一代改性环氧的性能要比传统的煤焦油环氧好。ASTM G8试验方法作为预选实验方法，不能给出不同涂层体系测试结果的正确排序，而改进的BS3900F10部分试验方法可以给出正确的排序。     

有机涂层阴极剥离作用研究进展

介绍和评述了阴极剥离对有机涂层劣化和涂层下金属腐蚀过程影响的研究现状,讨论了影响阴极剥离发生与发展的因素、阴极剥离作用机理和提高有机涂层耐阴极剥离的途径.同时综述了研究有机涂层阴极剥离的测试技术和研究方法.     

极化电位对埋地钢质管道涂层剥离的影响

为了研究提高埋地钢质管道阴极保护电位对管道涂层剥离的影响,对退役的埋地管道提高保护电位,收集管道的通电电位和断电电位数据,并测量涂层的阴极剥离距离。结果表明:当断电电位达到-1.2 V时,管道的通、断电电位绝对值并不一定随着距离的增加而减小;此外,不同防腐涂层管道的阴极剥离距离不同。     

阴极保护条件下环氧基界面粘附性研究

用阴极剥离方法研究了3种类型环氧涂层在60℃的3.5%NaCl溶液中的抗阴极开裂行为,用静态浸泡方法测定了3种涂层自由涂膜在30%NaOH溶液中的增重动力学曲线,采用单向拉伸方法测定了涂层与基体金属的粘附力,从涂层的抗碱性及涂层与基体金属粘结性能分析了影响涂层阴极开裂的主要因素.结果表明阴极反应生成的碱性环境造成聚合物降解是导致涂层阴极开裂的主要因素,此外涂层与基体金属的粘附性能对涂层的开裂也有一定影响     

某油气田项目316L不锈钢海底管道表面绝缘涂层的筛选

某海上油气田开发项目设计要求对316L海底管道内表面涂覆涂层以保证绝缘。分别在316L不锈钢表面涂覆7种涂层,通过高温高压反应釜模拟海底管道内部服役环境进行浸泡试验,对比浸泡试验前后涂层的表观、附着力、耐磨性、硬度、剪切强度、耐划伤等性能。结果表明:涂层2、涂层5和涂层3等3种涂层性能优异,这为油气田开发工程设计的涂层选择提供了参考依据。     

提高管道外防腐层施工质量的途径

已广泛应用的三层聚烯烃结构防腐层(3LPO)和单层熔结环氧粉末涂层(FBE)已相继发生了多起投产运营三五年后防腐层粘结性下降并完全失效的事故.为减少此类事故的发生,提出了通过提高表面处理质量和优化环氧粉末涂敷工艺来改进管道外防腐层施工质量的途径,并通过实例进行了效果验证.结果表明,上述措施改进效果明显,可推广使用.     

Modified tensile adhesion test for evaluation of interfacial toughness of HVOF sprayed coatings

Tensile adhesion test is widely used to evaluate the adhesion strength of coatings sprayed by High Velocity Oxy-Fuel (HVOF) technique. But there are two issues to be improved. Firstly, when the coatings have high adhesion strength, failure occurs in an adhesive layer, and secondary, the edge of a substrate is heavily deformed and rounded due to the high impact energy of sprayed particles. This deformation causes large scatter of adhesion test results. In this paper, a new technique to evaluate the interfacial fracture toughness has been proposed by introducing pre-crack at the interface of a conventional tensile adhesion test specimen. The asymptotic analytical formula was derived for interfacial toughness evaluation. Numerical analysis was also carried out for comparison. The difference between the numerical and the theoretical data was less than 5%. The developed procedure was applied for the SUS316 L steel coatings and the significant effects of the surface roughness and preheating temperature on adhesion strength were reconfirmed quantitatively.     

浅谈国内外埋地管线外防护层修复的材料选择及应用

国外经较长时间的开发和应用,对旧管线修复的防护层材料选用,修复工艺等均有一些基本规定,近几年我国在此方面也开展了不少研究和应用。本文重点介绍目前国内外对埋地管道外防护层修复材料的选择原则,部分修复材料特性及相关修复工艺的研究和应用。     

碳黑掺杂型导电有机涂层的防护机制

 利用碳黑掺杂的方法制备熔融结合环氧(FBE)导电涂层，选用电化学阻抗谱法(EIS)、热重分析(TGA)和差示扫描量热(DSC)等手段研究了其在3%NaCl溶液中失效过程及防护机制.结果表明:与相应的含有少量碳黑的绝缘FBE涂层相比,导电FBE涂层体系的防护性能显著提高,这得益于导电涂层中碳黑连续网络增加了腐蚀介质的传输阻力；对涂层保护下金属基材腐蚀形貌的分析均证明了此结论.        

钢质套管对埋地管道阴极保护的影响

分析钢质套管对埋地管道阴极保护影响的原因,提出管道设计施工、阴极保护系统设计施工中与此有关的改进意见。     

Localised corrosion of cathodically protected pipeline steel under the effects of cyclic potential transients

Cathodic protection (CP) may lose its effectiveness for protecting buried steel pipeline from soil corrosion due to the effects of potential excursions caused by stray currents. In this work, dynamic localised corrosion processes of buried steel due to the effects of cyclic potential transients have been visualised using an electrochemically integrated multi-electrode array, often referred to as the wire beam electrode (WBE). The focus has been on the understanding of the effect of cathodic transients. The WBE maps suggest that the amplitude of cathodic transient, as well as the ratio of anodic cyclic to cathodic cyclic, can significantly affect the corrosion rates and patterns. In particular, if the cathodic transient leads to a very negative potential, e.g. ?1350?mV_vs.CSE, rapid corrosion would occur on buried steel surface. These results have implications for CP parameter selection for preventing stray current-affected buried steel pipelines.     

Study of the Influence of Particle Velocity on Adhesive Strength of Cold Spray Deposits

The adhesion mechanism of deposit/substrate interface prepared by the cold spray method is not fully understood at present. It seems that the adhesion strength is mainly determined by the mechanical (including the plastic deformation of particle and substrate) and thermal interaction between particle and substrate when the particles impact onto the substrate with a high velocity. In order to understand the adhesion mechanism, a novel adhesive strength test was developed to measure the higher bonding strength of cold sprayed coatings in this study. The method breaks through the limits imposed by glue strength in the conventional adhesive strength test, and it can be used to measure the coatings with a higher adhesive strength. The particle velocity was obtained with DPV-2000?measurement and CFD simulation. The relationships between the adhesion strength of deposits/substrate interface and particle velocity were discussed. The results show that stronger adhesion strength can be obtained with the increase of particle velocity. There are two available ways to improve the adhesion strength. One is to increase the temperature of working gas, and another is to employ helium gas as the working gas instead of nitrogen gas.     

Ni-P-SiC composite coatings electroplated on carbon steel assisted by mechanical attrition

Ni-P-SiC composite coatings were electroplated on carbon steel substrate assisted by mechanical attrition (MA). The MA action was conducted by dispersing glass balls on the cathodic surface, vibrating in the horizontal direction. The experimental results show that, under the assistant of MA action, the adhesion of Ni-P-SiC coating on the steel substrate can be improved effectively, and the Ni-P-SiC coatings exhibit a crystallized structure and Ni-P matrix can combine tightly with SiC particles, and the hardness and corrosion resistance of these coatings increase markedly. During heat treatment, the defects produced in conventional Ni-P-SiC composite coatings can be avoided assisted by MA action. Both of the wear resistance and corrosion resistance of these coatings can be improved further.     

埋地钢质管道强制电流阴极联合保护研究

目的验证阴极保护系统在保护目标管道的同时对临近管道造成的杂散电流腐蚀,对比柔性阳极与阳极地床在保护管道的过程中产生的杂散电流污染情况,确定同沟铺设的不同管道联合保护方案。方法通过同一排流设备对相同区域的不同管线进行统一保护,阴极保护系统中的接地装置作为唯一的阳极,多条埋地管线作为电化学电池的阴极实现保护。结果阳极地床产生的杂散电流干扰明显强于柔性阳极材料;排流保护中,两条20 m埋地金属管道达到排流保护的范围时,柔性阳极的排流电压为1.2~1.52 V,远小于碳钢阳极地床的3.5~15 V,能够有效减少防护过程中电能的使用。结论同一阴极系统同时对多条金属管道或金属构筑物进行排流保护的措施可行。