The Corrosion Protection Behaviour of Zinc Rich Epoxy Paint in 3% NaCl Solution

Electrochemical impedance spectroscopy (EIS) in the l00 kHz-10 mHz frequency range was employed as the main electrochemical technique to study the corrosion protection behaviour of zinc rich epoxy paint in 3% NaCl solution. The EIS results obtained at the open-circuit corrosion potential have been interpreted using a model involving the impedance of particle to particle contact to account for the increasing resistance between zinc particles with immersion period, in addition to the impedance due to the zinc surface oxide layer and the electrical resistivity of the binder. Galvanic current and dc potential measurements allowed us to conclude that the cathodic protection effect of the paint takes some time to be achieved. The loss of cathodic protection is due to a double effect: the decrease of the Zn/Fe area ratio due to Zn corrosion and the loss of electric contact between Zn to Zn particles. Even when the cathodic protection effect by Zn dust become weak, the substrate steel is still protected against corrosion due to the barrier nature of the ZRP film reinforced by Zn.

Effect of Corrosion Inhibitor Used in Surface Treatment on the Anticorrosive Performance of an Epoxy Paint System

The mechanism of corrosion is mainly sustained by an electrochemical process, in which anodic and cathodic reactions take place, keeping their kinetics alive by electrons and ions fluxes. Several specific conditions can accelerate corrosion processes. When studying anticorrosive coatings, one of them is the contamination of metallic surface by soluble salts prior to coating, leading to premature failure of the paint system due to corrosion between the metallic surface and the coating. So the surface preparation step prior to coating is a procedure of great importance to the coating anticorrosive performance. The aim of this step is to clean the surface by removing visible and non-visible contaminants. Usually, wet abrasive blasting methods are the most efficient ones to achieve the latter objective, because they may clean the surface, create a surface roughness and also remove the non-visible contaminants, as they use water as a media. On the other hand, evaporation of water after blasting may create flash rust and to avoid this, it is common to use corrosion inhibitors in the water of wet blasting methods. In this paper, the use of sodium tetraborate (borax) as a corrosion inhibitor in wet abrasive blasting is discussed. Electrochemical measurements and mass loss tests show that a borax content of 1% in a saline solution has the best inhibitory action over carbon steel and zinc surfaces, allowing postponing for the painting step some time. However, residual borax left on the surface generated blistering and corrosion under coating, during accelerated corrosion test in a humidity condensation chamber. Electrochemical impedance spectroscopy confirmed that borax accelerated the permeation of water through the coating, downgrading the anticorrosive performance of the paint system.

水泥改性水性环氧涂料的制备及性能

[目的]聚合物水泥防水涂料在应用于水工混凝土时的粘结强度亟待提高。[方法]将硅酸盐水泥作为第三组分对水性环氧涂料进行改性,研究了水泥掺量(占与石英共同组成的填料质量的10%~50%)对涂料力学性能和防护性能的影响。采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和傅里叶变换红外光谱仪(FTIR)分析了水泥对水性环氧乳液的改性机理。[结果]在40%的水泥掺量下,涂层的力学性能和防护性能最优,粘结强度、拉伸强度和断裂伸长率分别为6.14 MPa、2.16MPa和156%,浸水、浸碱和冲蚀后未出现吸水溶胀现象,粘结强度下降和质量损失的程度最小。[结论]水泥的掺入明显改善了涂层的力学性能和防护性能,环氧乳液聚集包裹在石英砂、水泥及其水化产物周围,形成了以环氧乳液为主要成膜物质,石英砂、水泥及其水化产物为次成膜物质的互穿网络结构,CaCO_(3)的存在使网络结构更为致密。

大型球罐壁面除漆机器人设计与实验研究

为解决大型球罐压力容器表面三层高强度环氧漆打磨问题,设计了一款大型球罐壁面除漆机器人,并对其开展了实验研究。机器人主要包括爬壁吸附系统和自适应打磨系统。通过对海尔贝克阵列永磁体研究,仿真分析履带结构永磁体吸附力与工作间隙的关系,研发了一款吸附稳定、越障性能优越的爬壁吸附系统;针对弧形壁面打磨情况,设计了一款基于电流反馈的自适应打磨系统,并分析金属丝打磨辊力学模型,研发多样金属丝打磨辊。对机器人进行测试,打磨效果良好,机器人可以对环氧漆打磨并露出金属光泽,且是人工打磨效率的3~10倍。该研究为球罐高强度环氧漆打磨提供了新打磨工具,保证了打磨质量,提高了打磨效率。

环氧酯改性水性丙烯酸树脂的制备及漆膜性能

为了提高丙烯酸树脂的耐水性、附着力以及耐溶剂性,以桐油酸和环氧树脂E-44为原料制备环氧酯,采用溶液聚合和自乳化工艺合成了环氧酯改性水性丙烯酸树脂,并引入氰特CY325氨基树脂制备双组分环氧酯改性水性丙烯酸树脂漆膜。利用FT-IR、1 H NMR、粒径测试等对环氧酯单体、环氧酯改性水性丙烯酸树脂的结构和性能进行表征和分析,并测试了单组分和双组分环氧酯改性水性丙烯酸树脂漆膜的硬度、光泽、吸水率、水接触角、耐溶剂性等性能。结果表明:当环氧酯用量为35%时,单/双组分漆膜综合性能达到最佳,双组分漆膜光泽(60°)达102.3,耐溶剂擦拭次数为500次,耐水性可达480 h,附着力为0级,铅笔硬度为4H,耐冲击性为50 cm。

含不同改性剂的纳米防腐色浆对金属防腐涂料性能的影响

[目的]对颜填料进行化学改性虽然能解决与涂料树脂的相容性问题,但可能影响涂层的防腐性能。[方法]将用含有GL-1110(酸性基团改性的硅氧烷低聚物)和GL-527(氨基硅氧烷低聚物)改性剂的纳米防腐色浆制备的环氧-硅溶胶涂料喷涂在Q235钢表面(干膜厚度均为25~26μm),测试了涂层的主要性能。[结果]两种涂层的铅笔硬度均为6H,附着力均为0级,耐紫外老化试验500 h后均不开裂、不起泡,仅轻微变色,表明改性剂对涂层的物理性能没有明显影响。在3.5%NaCl溶液中进行的电化学阻抗谱(EIS)测量和中性盐雾(NSS)试验的结果均表明,以GL-1110改性防腐色浆制备的涂料有更好的耐腐蚀性能。[结论]GL-1110能够让功能性防腐颗粒在涂料中更均匀地分散,充分发挥其屏蔽作用,并杜绝缺陷的产生。

石墨烯改性水性环氧富锌防腐涂层的制备及耐蚀性研究

[目的]将石墨烯(GE)作为改性剂引入水性环氧富锌(ZRE)涂层之中,探讨不同锌含量下添加石墨烯对其力学、电学及防腐性能的影响。[方法]通过划格附着力和耐冲击性测试考察了涂层的力学性能,根据表面电阻率、体积电阻率、吸水率和中性盐雾测试结果来评价石墨烯改性水性环氧富锌涂层的防腐效果。[结果]随着锌粉含量的增加,引入少量石墨烯能明显提高涂层的导电性和耐蚀性,但添加过多会导致涂层性能变差。综合力学、电学和耐腐蚀性能得出在锌含量70%的水性环氧富锌涂层中加入约0.9%的石墨烯效果最好。[结论]石墨烯添加量增大而导致的腐蚀微电池增多是涂层防腐蚀性能下降的主要因素,明确涂层中石墨烯与锌、铁之间的共存关系有望进一步提升水性环氧富锌涂层的综合性能。

抗腐蚀蔓延水性环氧富锌涂料的制备与性能

[目的]要延长涂层的使用寿命,需阻止腐蚀介质沿着涂层被划伤的部位侵入而腐蚀金属基材,抑制腐蚀蔓延。[方法]选用环氧树脂乳液、胺类固化剂、颜填料、腐蚀抑制剂及其他助剂制备了一种具有优异抗腐蚀蔓延能力的水性环氧富锌涂料,讨论了成膜物质含量、固化剂种类和颜填料复配形式对涂层耐蚀性的影响,探讨了涂层抗腐蚀蔓延的机理。[结果]在成膜物质的质量分数为15%,选用聚酰胺固化剂,以绢云母、超磷锌白和石墨烯作为颜填料,并加入适量腐蚀抑制剂的情况下,所制备的涂料综合性能最好,其涂层经中性盐雾试验2 160 h后依然具有良好的附着力,平均扩蚀宽度仅为1.43 mm。[结论]腐蚀抑制剂对涂层湿态附着力的提升,以及石墨烯对锌粉利用率的提升,共同赋予了该涂层优异的抗腐蚀蔓延性能。

汽车零部件用单组分水性环氧厚浆底漆的研制

[目的]拟制备一种性价比高的汽车零部件用水性环氧厚浆底漆以满足市场需要。[方法]研究了作为主要成膜物的水性环氧乳液EV6102与水性丙烯酸乳液LR-2052的质量比,气相二氧化硅CT-200与水性膨润土BP-188L的用量,以及增稠剂的选择对涂料性能的影响。[结果]当水性环氧乳液EV6102与水性丙烯酸乳液LR-2052的质量比为1∶2,气相二氧化硅CT-200、水性膨润土BP-188L和增稠剂ACRYSOL ASE60的质量分数分别为0.5%、0.4%和0.2%时,制得的涂料初期耐水性好,铅笔硬度为H,耐中性盐雾时间300 h,耐水时间1200 h,VOC(挥发性有机化合物)含量30 g/L,单道涂层厚度可达到150μm。[结论]该单组分底漆涂膜的各项性能满足汽车零部件用底漆的要求。

某住宅楼地下车库地坪漆开裂原因分析

某大型住宅区地下负一层停车库,地面铺装材料为环氧地坪漆,在使用不到半年后,地面环氧地坪漆发生大面积开裂、起壳、剥落,开裂部位不均匀分布。通过检查停车库地面施工构造,检测各种施工材料的性能,分析出停车库地面混凝土的施工工艺及找平层混凝土自身性能是造成环氧地坪漆开裂的主要原因,为同类型的施工项目提供案例参考,避免类似情况发生。

南沙大桥钢桥面铺装防腐层施工工艺

为指导钢桥面防腐层施工,通过钢桥面板喷砂除锈及环氧富锌漆施工工艺研究,确定了喷砂除锈和环氧富锌漆施工关键技术控制指标,研究表明,抛丸机采用丸砂比为2∶1时,行走速度不得>3.0 m/min;采用喷枪喷涂环氧富锌漆,漆膜厚度均匀性要优于人工滚涂,且合格率相对较高;喷枪喷涂和人工滚涂环氧富锌漆对其拉拔强度影响不大。通过防腐层施工工艺研究,验证了防腐层施工关键技术与工艺的合理性。

Electrochemical behavior of organic and inorganic zinc-rich coatings in 3.5% NaCl solution

Performance comparisons between organic and inorganic zinc rich paints (ZRPs) were carried out. Electrochemical impedance spectroscopy (EIS) measurements were used to assess the corrosion prevention performance of the ZRP coatings. The results show that during the cathodic protection period the potentials of the epoxy systems are less negative than those of the silicate system. For the zinc rich ethyl silicate paints, the initial values of the resistance through the binder and the charge transfer resistance associated with zinc dissolution are several orders of magnitude lower than those of the organic zinc paints, while the initial values of the capacitance due to the binder layer between Zn dust and the double layer capacitance for zinc dissolution are several orders of magnitude higher than those of the organic zinc paints. Furthermore, the deterioration with time of capability of the zinc particles in the paint to provide cathodic protection to the steel was interpreted.

PF/EP/Nano-SiO_2 Composite Paint for Resistor

Phenolic resin(PF) and nano-SiO2 were used to improve the curing property and high humidity resistance of epoxy resin (EP) and methyl nadic anhydride (MNA) resistor paint, respectively. Hydrogen bonds, formed between phenolic resin and nano-SiO2 in alcohol, made nano-SiO2 disperse easily in EP/MNA paint through phenolic resin without being treated by supersonic vibration. When the mass ratio of PF to EP in paint is 3:7, the formed composite paint film can be cured in 2 min at 170 ℃ . When the mass ratio of nano-SiO2 to PF in paint is 3:100, the property of high humidity resistance of the composite paint is the best, meeting the requirement of varying ratio of resistance less than 0.1% after experiment on high humidity resistance. SEM analysis shows the surface of the composite paint film is smooth, glassy, tight and homogeneous, without acicular air holes.

Respiratory Sensitization &Sickness from Welding/Burning Isocyanate Containing Paints

The purpose of this paper is to make the environmental and occupational health community aware of a serious health risk associated with the common practice of burning industrial paint off of metal surfaces during or prior to welding. On four occasions bystanders and welder/burner personnel have experienced illness as a result of being exposed to the combustion products of isocyanate paints that were being burned off metal surfaces. In each case, the burning and the exposed people were outside in an open environment where the health risk was thought to be minimal due to the open environment with nominal wind movement through the work area. In one case, the person (a burner) developed permanent sensitization to phthalic anhydride as a result of the exposure. Phthalic anhydride was determined to be decomposition product of burned isocyanate paint. In the other three cases (which involved very short exposures), between two and six people became ill but did not develop sensitization. Their symptoms included dizziness, nausea, headache, and breathing difficulty the severity of which varied from very uncomfortable to temporarily incapacitating. This paper discusses the circumstances associated with each event, the approach used to determine that phthalic anhydride was a decomposition product, and some practical things that can be done to avoid having employees become victims of exposure.

600 Mesh Silicon Carbide Corona Protection Varnish with EPOXY/OMMT Nano-composite Adhesive

A new corona protection varnish was prepared by using epoxy/montmorillonite nanocomposite and pure epoxy resin as adhesives respectively.The adhesive with different amounts of organic montmorillonite（OMMT） was mixed with 1200 mesh silicon carbide（Si C） by different weight ratios.The surface states of the varnishes with various adhesives were observed by powerful optical microscope.Some properties of the varnishes were analyzed during the enduring time under 5kV/cm DC,such as the relation of change in nonlinear coefficient,natural surface resistivity,and surface temperature variation.The results showed that the amounts of OMMT had little effect on the natural surface resistance of the varnish but had important influence on the nonlinear property of the varnish.When the range of the OMMT content was 2wt% to 6wt%,the nonlinear coefficient of all materials with epoxy/OMMT nano-composite adhesive was higher than that with pure epoxy resin adhesive.The surface temperature of the varnish with epoxy/OMMT nanocomposite adhesive was all lower than that with the pure epoxy resin adhesive under high electrical field strength.

环氧乳液和防锈剂对水性防腐涂料性能的影响

研究了不同环氧乳液和防锈剂配比对水性防腐涂料主要性能的影响。结果发现:当DER-425环氧改性乳化剂的质量分数为14%,DER-439环氧树脂的质量分数为56%时,合成的环氧乳液的平均粒度为923 nm,黏度为4.1 Pa·s,涂层表现出良好的耐硫酸、盐酸、丙酮和二氯乙烷性能。当采用质量分数为0.6%的石墨烯对环氧乳液进行改性,且石墨烯改性乳液与复合亚磷酸锌铝盐防锈剂的质量比为(6~8)∶1时,涂料通过了1104 h的中性盐雾试验,最大冲击高度达到50 cm,耐酸和耐有机介质的性能较佳。

膨胀型钢结构防火涂料的制备及性能

为提高涂料的耐火性能以更好地保护钢结构,以水性环氧乳液和固化剂作为基料,聚磷酸铵(APP)-季戊四醇(PER)-三聚氰胺(MEL)作为阻燃体系,可膨胀石墨(EG)作为阻燃助剂,粉煤灰漂珠与纳米TiO2作为填料,研制了一种膨胀型钢结构防火涂料。考察了各组分用量对涂料性能的影响,采用扫描电镜(SEM)对防火涂层燃烧前后的微观结构进行了表征,并分析了涂层厚度对耐火时间的影响。结果表明:水性环氧乳液、固化剂和EG的最佳用量分别为20.0%、4.0%和4.5%,纳米TiO2与粉煤灰漂珠的最佳质量比为1∶1。当APP、MEL和PER的质量分数分别为28.0%、18.0%和18.0%时,涂料的耐火时间最长。发生燃烧之后的“蠕虫”形EG会与基料树脂发生膨胀并与无机层粘合形成无机保护层,膨胀体系相互发生反应,粉煤灰漂珠均匀完整地附着在基材表面,使之具有良好的隔热性能。所制备的防火涂料的最佳涂覆厚度为1.9 mm,耐火时间为107 min。

石墨烯对环氧树脂交通标线涂料性能的影响

选用双酚A型环氧树脂为主要成膜物质制备疏水耐磨型交通标线涂料,探讨了不同类型的石墨烯或氧化石墨烯掺量(质量分数0.05%、0.10%、0.15%、0.20%、0.25%或0.30%)对涂层疏水性、耐磨性、耐蚀性等性能的影响。结果表明,添加少层或多层的石墨烯或氧化石墨烯对涂层的硬度、耐水性和耐盐水性的影响不大,但能不同程度地提高涂层的附着力、柔韧性、耐冲击性、疏水性、耐磨性、耐酸性和耐碱性。当少层氧化石墨烯质量分数为0.10%时,涂层的综合性能最好,水接触角达到131.977°,吸水率为1.11%,铅笔硬度为6H,柔韧性为1 mm,附着力为0级,耐1 kg冲击的高度达到50 cm。

Evaluation of Corrosion Stability of Water Soluble Epoxy-Ester Primer through Electrochemical Studies

The corrosion behavior of water borne epoxy-ester primer coatings (10% - 50% PVCs) was evaluated through electrochemical techniques such as polarization and impedance spectroscopic (EIS) measurements. Studies were carried out for a longer duration of exposure extending up to 60 days in aqueous solution of NaCl (5%). Corrosion current (icorr), Corrosion potential (Ecorr), Coating resistance (Rc), Charge transfer resistance (Rct), Coating capacitance (Cc), Double layer capacitance (Cdl), break point frequency (fb), Water uptake (∮), diffusion coefficient (Dw) etc., indicated that 10% - 30% PVC coatings performed well in comparison to higher PVCs. Changes in the electrochemical characteristics were found to occur as a function of exposure time in all cases. The corrosion stability of the coatings were found to be greatly affected by the percentage of PVCs. Studies further indicated that when lower concentration of pigments were available, they remained completely surrounded by the binder;Thus leaving no space for the entry of corrosive agents. From these studies, it was concluded that the water borne paints could replace the conventional coatings, containing organic solvents. Therefore, water soluble epoxy-ester primers have to be employed in paints for developing eco- friendly coatings.

一种快速固化耐酸防腐酚醛环氧涂料的研制

针对储存酸性介质的石油化工储罐及压力容器的防腐需求,采用F-51、F-53酚醛环氧树脂,Ancamine 2753脂环胺和NX-2003D腰果壳油改性酚醛胺固化剂,添加叔胺固化促进剂,辅以0.8%的石墨烯分散体、5%的苯甲醇增塑剂等原料,研制出一款耐酸性介质性能优异的快速固化防腐涂料。它附着力高,常温下固化只需4 d,适用于油田与化工储罐及压力容器的现场防腐维修。