氟碳涂层对海洋环境下混凝土抗氯离子渗透性能的影响

目的研究不同氟碳涂层体系对海洋环境下混凝土抗氯离子渗透性能的影响规律及作用机理。方法以溶剂型氟碳涂层和水性氟碳涂层为研究对象,开展了两种溶剂型氟碳涂层体系和一种水性氟碳涂层体系的研究,即环氧底漆-溶剂型氟碳面漆、环氧底漆-聚氨酯中层漆-溶剂型氟碳面漆及水性环氧底漆-水性氟碳面漆。通过氯离子电迁移快速试验,研究涂覆这三种氟碳涂层体系的混凝土抗氯离子渗透性能。采用干湿循环试验模拟浪花飞溅区,通过混凝土抗氯离子侵蚀试验及扫描电镜观察试验,研究涂层对混凝土在海洋环境浪花飞溅区的防腐性能。结果氯离子电迁移快速试验测得的氯离子扩散系数表明,氟碳涂层体系作用下,混凝土氯离子扩散系数降低。干湿循环试验36 d后,通过扫描电镜观察发现这两种溶剂型氟碳涂层体系表面仍然致密,水性氟碳涂层体系表面出现裂缝。结论溶剂型和水性氟碳涂层体系均能提高混凝土抗氯离子渗透性,溶剂型氟碳涂层体系在海洋浪花飞溅区更耐久,更适用于该环境下的混凝土腐蚀防护。     

聚氨酯改性环氧树脂防腐涂料的研制

以聚氨酯改性环氧树脂为成膜物质,磷酸锌和三聚磷酸铝为颜料,滑石粉、绢云母、纳米二氧化硅和纳米二氧化钛为填料,制备了聚氨酯改性环氧树脂防腐蚀底漆.检测了底漆的机械性能、电化学阻抗谱和耐化学介质性能.研究了磷酸锌和三聚磷酸铝两种防锈颜料的配合使用对涂层防腐耐蚀性能的影响.结果表明,防腐底漆的机械性能和耐蚀性能良好.     

混凝土桥梁耐酸雨防腐蚀涂料

介绍了国内外在耐酸雨防腐蚀涂料领域的研究概况和酸雨对混凝土侵蚀的形成,研制了一种专用于混凝土桥梁耐酸雨的防腐蚀涂料,分析了树脂组成对其性能的影响,得出底漆中环氧树脂与呋喃树脂的比例以70/30为宜,面漆中有机硅树脂掺入量以10%～20%为宜.     

电化学阻抗谱评价输电铁塔防护涂层配套性能

研究了用于输电铁塔防护的带锈环氧底漆（A）、水性环氧防锈底漆（B）、氟硅改性丙烯酸面漆（C）、有机硅改性醇酸树脂面漆（D）所组成的4个涂层配套体系的电化学阻抗谱图特征。通过研究涂层电阻、涂层孔隙率和10kHz下的涂层相对介电常数对4种涂料配套体系的防腐蚀性能进行了比较和评价。结果表明,4个配套涂层体系防护性能的优劣顺序...     

亚光铁红环氧酯防锈底漆的制备及其PVC与光泽的探讨

介绍了亚光铁红环氧酯防锈底漆的制备过程,探讨了亚光铁红环氧酯防锈漆PVC与光泽的关系,在不改变底漆其它性能的条件下,通过改变配方中原材料的用量,来调整颜料体积浓度(PVC)值,试验得到底漆的PVC值在42%左右,符合亚光铁红环氧酯防锈底漆行业标准40%～55%的范围,能达到理想的亚光效果.     

凝石混凝土的抗氯离子渗透性能研究

由钢筋锈蚀导致的混凝土结构耐久性问题受到越来越多的关注,而氯离子是造成钢筋锈蚀的主要原因.采用ASTMC1202推荐的快速试验方法对比测定了氯离子在凝石混凝土和水泥混凝土中的渗透能力,结果表明:凝石混凝土的抗氯离子渗透性能优于水泥混凝土,其机理在于凝石混凝土的孔结构优于水泥混凝土及凝石对氯离子较强的固化能力.     

凝石混凝土的抗氯离子渗透性能研究

由钢筋锈蚀导致的混凝土结构耐久性问题受到越来越多的关注，而氯离子是造成钢筋锈蚀的主要原因。采用ASTMC1202推荐的快速试验方法对比测定了氯离子在凝石混凝土和水泥混凝土中的渗透能力，结果表明：凝石混凝土的抗氯离子渗透性能优于水泥混凝土，其机理在于凝石混凝土的孔结构优于水泥混凝土及凝石对氯离子较强的固化能力。     

锈蚀输电铁塔防腐蚀底漆与涂装体系选择

对锈蚀输电铁塔进行磷化处理,以磷化膜作为底层,制备四种防腐蚀底漆试样,在此基础上,设计四种涂装体系并制备试样,按照国家相关标准对底漆试样和涂装体系试样进行机械性能和耐蚀性检测。结果表明,环氧铁红防锈底漆与磷化膜配套性能最好,附着力为0级,耐氯化钠浸泡时间可达720h,划格盐雾试验72h无变化,耐盐雾腐蚀试验1 000h无起泡、锈蚀、脱落等现象;环氧铁红防锈底漆、环氧云铁中间漆和氟碳面漆组成的涂装体系机械性能和耐蚀性能最佳,附着力为0级,耐碱与耐水时间均达480h,耐盐雾腐蚀试验3 000h无起泡锈蚀脱落等现象。     

无毒防锈颜料在水性马来酸酐共聚物涂层中的防腐蚀性能

研究了添加第二代无毒活性磷酸盐SAPP和SRPP的水性马来酸酐共聚物涂层的防腐蚀性能.通过盐雾试验、电化学阻抗谱(EIS)和浸泡试验研究这两种防锈颜料分散在水性马来酸酐共聚物涂层后对基材的防腐性能.结果表明两种防锈颜料加入涂层后都能明显提高涂层的防腐蚀性能,且SRPP颜料的防腐蚀效果优于SAPP颜料.     

我国工业防腐蚀涂料的7大发展方向

（1）开发钢结构用水性防腐蚀底漆和面漆。水性防腐蚀底漆必须解决底材＂闲蚀＂和耐水性差的难题。一些新型的无乳化剂乳液的出现从根本上解决了其耐水性差的问题，今后应重点解决施工性能和应用性能的问题。作为面漆来说，主要是在保证保护性能的前提下，提高其装饰性和耐久性。[第一段]     

一种新型钢筋阻锈剂的阻锈性能

采用硬化砂浆和半电池电位法评价了一种自制的含有氨基和羧基的新型钢筋阻锈剂IH_2的阻锈性能,并采用标准工作曲线法分析了混凝土中钢筋对阻锈剂的吸附性能。结果表明,IH_2钢筋阻锈剂可以延长钢筋发生锈蚀的时间,降低钢筋的腐蚀速率,具有良好的阻锈性能。     

Performance Evaluation of a Commercial Polyurethane Coating in Marine Environment

A material evaluation study has been carried out to determine corrosion behavior of a commercial polyurethane coating system (Souplethane 5) in the marine environment. The coating system is solvent free, two-component polyurethane protective coating. The performance of the coating on steel and rebar concrete was evaluated by conducting different types of tests which include atmospheric exposure, immersion in 5% sodium chloride solution, exposure to splash zone in seawater, salt fog, sabkha soil burial, and electrochemical tests, which include potentiodynamic polarization and AC impedance measurements. Uncoated, coated, and coated scribed specimens were used in each study. In general, the coating showed good corrosion resistance in marine environment. However, the coated samples, when subjected to break under applied compressive load, showed partial or complete detachment from the substrate, e.g., steel and rebar concrete. This appears to be the major drawback of the coating while applying on steel and concrete structures.     

环氧涂层钢筋及其应用

钢筋的腐蚀，尤其当有氯离子存在时，是混凝土结构腐蚀破坏的主要原因。在防止钢筋腐蚀的各种措施中，采用涂层既简便又有效。熔融结合环氧粉末涂层的综合防护性能优良，已经大量应用于钢质管道和钢管桩，也很适合于钢筋的保护。钢筋表面涂装环氧涂层可用静电喷涂方法，工艺基本成熟。环氧涂层钢筋的研究开发在美国始于20世纪的70年代，主要应用于撒布化冰盐的路桥和各类海工结构。我国在1997年就制订了环氧树脂涂层钢筋的行业标准。目前，国内已能生产环氧涂层钢筋，并开始实际应用。随着我国国民经济的发展，越来越多的工程要求使用环氧涂层钢筋，市场前景肯定十分广阔。     

Characterisation of coating on rebar surface using Hot-dip Zn and Zn-4.9Al-0.1 misch metal bath

The corrosion of rebar is one of the primary causes of premature deterioration of the concrete structure. The ideal option to overcome this situation would be to provide corrosion protection right at the time of manufacturing of the rebar before it is encased in the concrete and hence, warrants the use of corrosion resistance rebar.The present paper outlines characterisation of coating obtained on rebar surface from pure Zn and Zn-4.9Al-0.1 misch metal bath. The coating was characterised by SEM, EDS, Galvanostatic and XRD techniques. In case of pure Zn bath, distinct phases such as eta, zeta, delta and gamma 1 and gamma were identified in coating where as in case of Zn-4.9Al-0.1 misch metal bath no such distinctive phases were found. The coating obtained from Zn-4.9Al-0.1 misch metal bath was thinner and consisted of outer Al₂O₃ phase followed Zn-Al phase resulting in better ductility compare to the coating obtained from pure Zn bath. Comparative corrosion resistance performances of both types of coating respect to uncoated rebar were evaluated by salt spray and tafel test. were conducted in simulated aggressive chloride and concrete pore solution of coated and The coating obtained form Zn-4.9Al-0.1 misch metal bath was found to be more anodic and showed 1.5-3 times better corrosion resistance in concrete pore solution and 2.5 times better resistance against aggressive chloride attack compare to the coating obtained from pure Zn bath. Both the coatings dissolved in faster rate in highly alkaline environment (pH = 13.6) where as dissolution rate decreased with decrease of pH in pore solution. The sacrificial as well as barrier protection of Zn-Al alloy coating was found to be more effective than pure Zn coating. Both types of coated bars showed reduction in bond strength in concrete structure. It is attributed by the faster dissolution of the coating, leading to hydrogen gas evolution thereby creating a gap between the rebar surface and concrete structure.     

国内外桥梁防腐蚀现状及今后发展趋势

本文概述了国内外桥梁(包括钢结构桥和混凝土桥)的防腐蚀现状,并列出典型的配套方案,针对现存缺点,并结合四川万州铁路长江大桥防腐涂装配套体系的选择试验,提出采用常温固化型氟碳涂料做桥梁防腐涂层的必然趋势.     

Effect of surface condition on the initial corrosion of galvanized reinforcing steel embedded in concrete

The present work was aimed at determining the effect of coating surface condition on the initial corrosion of hot-dip galvanized reinforcing steel bar (HDG rebar) in ordinary Portland cement (OPC) concrete. During zinc corrosion in OPC concrete, calcium hydroxyzincate (CHZ) formed on untreated HDG steel provided sufficient protection against corrosion. Therefore, it is concluded that treating HDG rebar with dilute chromic acid is unnecessary as a method of passivating zinc. A layer of zinc oxide and zinc carbonate formed, through weathering, on HDG bars increased the initial corrosion rate and passivation time compared with the non-weathered rebar exposed to concrete. HDG steel with an alloyed coating, i.e. containing only of Fe-Zn intermetallic phases, required a longer time to passivate than those with a pure zinc surface layer. The lower zinc content of the surface limited the rate of CHZ formation; hence, delayed passivation. Regardless of the surface condition, the coating depth loss after two days of embedment in ordinary Portland cement concrete was insignificant.     

脱硫系统烟气区混凝土及防护层现场腐蚀试验

选择普通玻璃鳞片涂料、耐高温玻璃钢衬里两种防腐蚀材料制作混凝土试块,同时与无保护的混凝土试块一起在脱硫系统烟气区进行现场腐蚀试验,试验周期为3个月、6个月。对试验后防腐蚀层外观、混凝土中钢筋的腐蚀形貌以及混凝土中氯元素等进行分析。结果表明,无保护混凝土试块,外界腐蚀介质已渗透到混凝土内部,导致钢筋出现非常明显的腐蚀;普...     

高速公路桥梁防撞墙防腐技术措施研究

为了优化高速公路桥梁防撞墙防腐效果,要明确防腐墙的腐蚀机理,然后利用细节分析方法,从防腐涂层设计、防腐涂层试验、混凝土表面处理、涂装施工等方面落实完整的防腐技术方案,这种处理方式较为便捷且成本较低,应用效果显著.     

Effect of plating time for electroless nickel coating on rebar surface: An option for application in concrete structure

The ternary Ni-P-Fe alloy coating was developed by an electroless process using a citrate bath. During the steel sample dip in bath, Fe will first get dissolved from the rebar surface and would subsequently get introduced in the bath as Fe²⁺. This, in turn, would activate the surface and Ni, P and Fe are co-deposited on the activated rebar surface. The first deposition layer would act as catalyst for subsequent metal deposition. The coating was characterised using SEM, EDS and XRD techniques. The bath pH was found to play a strong role on process kinetics as well as composition of the coating but not on coating structure. The weight percentage of Ni, P and Fe in the coating was found to have a relationship with the bath pH. The Tafel and salt spray test were conducted to find out corrosion resistance performance of the coatings. Electrochemical behavior of the coated rebars in simulated concrete environment was influenced by the pH of the concrete pore solution and the ‘P’ content in the coating. Corrosion potential and the corrosion rate of the coating increased with increase in ‘P’ content in the coating and pH of the pore solution, whereas the resistance against chloride attack of the coating increased with increase in ‘P’ content. The marginal drop in the bond strength of the coated rebar with the concrete structure may be due to the higher ‘P’ content which is expected to provide improved surface smoothness.     

Corrosion behavior of austenitic 304L and 316LN stainless steel clad reinforcing bars in cracked concrete

A study has been conducted on the chloride-induced corrosion behavior of 304L and 316LN stainless steel clad reinforcing bars (rebar) in concrete and in synthetic concrete pore solution. Metallographic examination of the as-received clad bars confirmed a strong metallurgical bond at the core/clad interface and some grain growth interdiffusion of species at the interface. Both bars showed a wide variation in coating thickness around the rebar circumference, from a minimum of 0.32 and 0.60 mm to a maximum of 1.4 and 2.8 mm in the 304L clad and 316LN clad, respectively. The electrochemical results and visual examination after autopsy showed that active corrosion was yet initiated on either the solid and clad stainless steel or carbon steel rebar in the sound noncracked concrete specimens. In contrast, corrosion had initiated in the bars embedded in cracked concrete at the base of the crack and extended along or around the bars. In the concrete and synthetic pore solution tests, the current densities of both solid and clad stainless steel rebar exposed to ∼21% chloride brine solution for days between 400 and 1,500 were similar. This was also the case for current densities of the straight and bent stainless steel bars tested in the synthetic pore solution test.