纳米TiO2涂层耐蚀性及抗紫外老化性能研究

通过添加改性纳米TiO2获得纳米复合涂层.采用紫外线加速老化试验和盐雾试验考察纳米复合涂层的抗紫外老化腐蚀性能.利用电化学测试(EIS)监测老化过程涂层性能变化并研究了纳米TiO2材料在涂层老化过程中的作用.结果表明,纳米TiO2材料的加入能够同时提高彩涂板涂层的抗老化及耐腐蚀性能,纳米TiO2质量分数为1%左右时其抗老化及耐腐蚀性能最佳.     

航空用氟聚氨酯涂层加速老化试验研究

选用飞机上广泛使用的氟聚氨酯蒙皮涂层,采用电化学交流阻抗技术(EIS)对其在加速老化试验过程中的阻抗变化进行了原位测试,分析了其腐蚀失效的特征.研究表明,氟聚氨酯涂层的缺陷较少,涂层可以很好地将腐蚀性介质阻挡在外,保护金属基体免受腐蚀破坏,此时涂层相当于一个纯电容.随着加速老化试验的进行,氟聚氨酯蒙皮涂层的失光率和色差变化较小,引起涂层体系失效的主要原因还是发生在涂层/金属界面的电化学反应.加速老化试验进行1680h后,氟聚氨酯蒙皮涂层的电化学交流阻抗谱上仍然显示的是纯电容性质,而且由等效电路计算出此时的涂层电容仍然很小,说明此时氟聚氨酯磁漆仍起着很好的保护基体的作用.与只喷涂锌黄丙烯酸聚氨酯底漆而没有氟聚氨酯面层的试样的加速老化试验结果比较可知,氟聚氨酯面漆可以有效提高底涂层抗老化和失效性能.     

铝合金材料涂层防护性能的试验研究

根据影响涂层老化的环境显著性因子,制定涂层实验室加速老化试验方案,进行2024铝合金防护涂层的实验室加速老化试验,对其试验结果进行粉化、失光、色差分析。结果表明,该加速老化试验方案对所采用防护涂层体系具有很好的加速性。     

循环加速腐蚀中紫外照射对环氧涂层老化行为的影响

采用傅里叶红外光谱(FTIR)、扫描电子显微(SEM)及电化学交流阻抗(EIS)技术,研究了环氧涂层在两种循环加速腐蚀(湿热-盐雾-疲劳和湿热-紫外-盐雾-疲劳)中的表面形貌、化学组成以及电化学阻抗特性。无紫外的循环加速腐蚀后涂层中心部分表面形貌无明显的变化,边缘部分涂层8个周期之后起泡破裂,破裂处出现了涂层下基体的腐蚀;有紫外的循环加速腐蚀过程中,紫外照射之后涂层表面粗糙度增加,出现粉化、失光现象,随循环加速腐蚀周期的增多涂层表面开始出现裂纹,且裂纹数量逐渐地增多。FTIR研究表明,无紫外的循环加速腐蚀后涂层结构无变化,而有紫外的循环加速腐蚀后涂层结构发生了明显的变化,高分子链断裂,O-H,C-H,C=C键及苯环等官能团消失。涂层在有紫外的循环加速腐蚀8个周期之后的电化学阻抗值仅为无紫外的1/2。     

海洋大气环境下纯聚脲重防腐涂层耐久性研究

通过FTIR、DSC等方法,研究了在海洋大气环境户外自然曝晒老化和紫外线人工加速老化条件下,纯聚脲重防腐涂层(Qtech-412涂层)的力学性能、光泽度和分子结构变化。结果表明:Qtech-412涂层经过600d户外自然曝晒老化后,光泽度下降94.53%,力学性能基本不变;经过15000h紫外线人工加速老化后,涂层表面失光,有机染料变黑,力学性能变化较小;FTIR和DSC试验表明上述两种老化方式都仅仅使涂层表面染料分子的化学键断裂,出现褪色或变黑现象,内部分子结构非常稳定;在人造海水的露天水池中曝晒6个月后的划叉破坏试验表明,Qtech-412涂层实际防腐效果优于其它重防腐涂层。目前Qtech-412涂层已成功应用于青岛海湾大桥承台结构防护工程。     

有机防护涂层老化研究进展

综述了以聚脲及聚氨酯涂层为代表的有机防护涂层在不同测试方法(SEM、AFM、FTIR、EIS、ATR等)和不同试验环境下的耐老化性能,包括有机防护涂层降解老化研究、腐蚀介质在涂层内的渗透性研究、涂层混凝土氯离子渗透性研究、有机涂层的老化研究及电化学阻抗测试研究。研究结果表明:涂层在不同老化条件下表现出不同的老化行为,紫外线/盐雾循环人工加速老化及Cl-在涂层中扩散最终都能导致涂层形貌破坏,防护功能下降;有机涂层附着力丧失及涂层失效程度可用涂层电容(C)值的迅速增加和涂层电阻(R)值的急剧降低为指标进行衡量。     

用人工加速老化法比较聚氨酯面漆和丙烯酸磁漆的性能

涂料在天然曝晒的条件下进行老化,需要很长的时间,不能快速比较其性能优劣,采用人工加速老化试验(氙灯老化法)对丙烯酸磁漆和聚氨酯面漆分6个周期(1周期:200 h UV和50 h盐雾)进行老化,用FTIR,SEM和光泽仪对老化的涂层进行分析表征,用交流阻抗(EIS)法来测试两种涂层抗渗水性能的强弱.结果表明,聚氨酯面漆抗紫外线的能力要比丙烯酸磁漆强;聚氨酯面漆的抗渗水性能强于丙烯酸磁漆.聚氨酯的综合性能强于丙烯酸磁漆.     

高固体分环氧防腐蚀涂层/铝合金在模拟超深海高压环境下的防护行为研究

为了提高铝合金在深海环境中的防护性能,研制了一种铝合金深海防护用高固体分环氧防腐蚀涂料.采用电化学测试技术、盐雾加速试验和涂层形貌分析等手段研究了高固体分环氧防腐蚀涂层在模拟常压海水环境和超深海高压环境(36.0 MPa)下对铝合金的防护行为.结果 表明:高固体分环氧防腐蚀涂料在铝合金基材上的耐盐雾寿命达1000h以上,涂层在铝合金上的拉拔附着力为11.28～13.52 MPa,经36.0 MPa高压盐水浸泡35 d后的湿附着力为7.52～8.12 MPa.铝合金/涂层体系在超深海高压环境下,漆膜吸水导致涂层电阻降低及电容逐渐增大,浸泡35 d后,涂层低频阻抗模值降低到3.85×106 Ω·cm2;深海高压导致涂层中的颜填料疏松,容易形成腐蚀通道导致涂层破损和基体腐蚀.提高涂层在金属上的湿附着力和致密性,是延长涂层在深海环境下防护寿命的关键因素.     

Cl~-对天然气管道内涂层破损处局部腐蚀的影响

为了进一步了解天然气管道内涂层破损处在含Cl~-电解质溶液中的破损机理,以X80管线钢为基材,利用EIS(电化学阻抗谱法)和SKP(扫描开尔文探针测试法)等电化学检测技术,通过获取内涂层破损处的腐蚀电化学参数的特性,研究了Cl~-浓度对特定缺陷尺寸内涂层破损处局部腐蚀的影响,并探讨其腐蚀机理。EIS谱结果表明,不同Cl~-浓度下的腐蚀过程经历了大致相同的规律,即随着浸泡时间延长腐蚀电阻出现先减小后增大的趋势;SKP测试表明,破损处周边的涂层/金属界面存在较大的电位差,在界面最易发生腐蚀,并随着浸泡时间延长,推动着腐蚀向涂层内部渗透,进而引发涂层不断剥离。     

聚吡咯导电涂层的制备及其性能研究

以十二烷基苯磺酸(BADS)为掺杂剂,过硫酸铵(APS)为氧化剂,化学法合成聚吡咯(PPy);并与羟基丙烯酸树脂配制成PPy导电涂层。用四探针测试仪测定不同反应条件下的PPy电导率,分析不同因素对PPy导电性的影响;运用扫描电镜(SEM)、激光粒度仪、电阻测试仪、紫外老化机、热分析仪、电化学工作站等对涂层进行表征。结果表明:PPy颗粒平均粒径约为1μm,且在涂层中分布均匀;20%PPy导电涂层的导电性最好,达到2.5×10^-4 S/cm;涂层经紫外加速老化720 h,导电性和附着力有所下降;涂层热稳定性较好,最终失重温度为500℃左右;PPy导电涂层的防腐蚀性优于纯树脂,5%PPy导电涂层的防腐蚀性最佳。     

Mechanical properties and adhesion strength of TiN and Al coatings on HSS, steel, aluminium and copper characterized by four testing Methods

TiN and Al coatings on substrates of high-speed steel, steel, aluminium and copper have been used to study mechanical properties of coating systems, especially the adhesion of the coating. The quantities measured are internal stress of the coating, determined by X-ray diffraction, the critical load of the scratch test, the microhardness obtained by the indenter technique, and the interface fracture energy, determined by a three-point bend test developed recently by the authors. The fracture energy, G_c, is a measure for the adhesion strength of a coating system. The effect of bias voltage, sputter cleaning and contamination of the substrates on the adhesion strength and other mechanical properties are investigated with the four methods mentioned. Each of the testing methods reveal only specific aspects of the behaviour of the coating systems. The data obtained depend on bulk properties of the film and the substrate material and on properties of the interface. Variation of the bias voltage can change them in quite different ways. In addition, the inter-relations between the adhesion strength of the coating and the failure behaviour of the three-point bend test samples are discussed.     

An Improvement on Adhesion of Sputtered TiC Coating to Steel Substrate

Introducing N_2 during sputtering andpre-oxidation of substrate were investigatedto improve the adhesion of sputtered TiC coatingto steel substrate. The results show thatyeactive gas N_2 increases the adhesion of TiCcoating to steel because of a graded interfaceexisting between coating and substrate. Theinteraction of discharge plasma with the surfaceof substrate was discussed. Pre-oxidation ofsubstrate is effective for improving the adhesiondue to the fomation of FeTi0_3 which appearedas an inteylayer between coating and pre-oxidizedsubstrate.     

Corrosion resistance of tannic acid,d-limonene and nano-ZrO_2 modified epoxy coatings in acid corrosion environments

The protection of rusted carbon steel in acid corrosion environments is of great significance for equipment to keep safe operation.In this work,we presented a method to protect the rusted steel by ru st conversion treatment and epoxy coating.Tannic acid was selected as rust conversion agent.Tannic acid,D-limonene and nano-ZrO₂were used to improve the corrosion resistance of epoxy coatings.The Raman spectra,Xray diffraction and 3 D confocal images were used to characterize the rust conversion reaction.Ad hesion test showed that the loss of wet adhesion of the optimal coating was relatively low due to the addition of tannic acid,limonene and nano-ZrO(2).The corrosion resistance of five different coatings was investigated by scanning electron microscopy(SEM)and electrochemical analysis.Results show that after 264 h acid immersion,the low frequency resistance of the optimal coating consisting of rust conversion treatment and additives is 10⁷Ωcm²,three orders magnitude higher than that of the pristine coating.Moreover,SEM indicates that the optimal coating possesses a smooth surface and an unbroken interface between substrate and coating.Accordingly,the corrosion-resistant mechanism of the hybrid coating is proposed.     

玻璃纤维/环氧树脂复合材料与镀层界面的Ni颗粒强化工艺

针对玻璃纤维/环氧树脂复合材料与镀层结合界面强度低的问题,基于复合材料/镀层间的机械互锁原理及传统塑料基体化学镀工艺,提出通过增强颗粒的桥接作用,增加含有增强颗粒的过渡层来强化镀层界面的复合材料金属化方法。对金属化后的玻璃纤维/环氧树脂复合材料试件采用拉伸试验法测量镀层的结合强度,并通过截面和断面的显微观测,分析了增强颗粒对于镀层界面的强化机制;同时获得了玻璃纤维/环氧树脂复合材料表面粗糙度和增强颗粒质量分数对含有过渡层的镀层结合强度的影响规律。结果表明:采用上述金属化方法可以显著提高镀层的界面强度,与传统的金属化工艺制备试件相比,玻璃纤维/环氧树脂复合材料在不同表面粗糙度下,镀层结合强度平均提高161%;同时,镀层的结合强度随着增强颗粒质量分数的增加,呈现先增大后减小的趋势,当增强颗粒的质量分数为50%时,镀层的结合强度达到最大。      

The degradation behavior of SiC coated PIP-C/SiC composites in thermal cycling environment

C/SiC composites had been considered as structural material in complex and harsh environments, thermal stability was one of the key issues for C/SiC composites. This study aimed to investigate C/SiC composites in thermal cycling environment. SiC coating on carbon fibers via chemical vapor deposition at time from 0.5 h to 5 h was studied, and then the degradation behavior of coated C/SiC composites had been measured by thermal cycling tests. The results showed that the coating was continuous and uniform, with good surface adhesion. The interface of carbon fibers and SiC coating was partially destroyed during thermal shock tests. The degradation of mechanical properties was closely related to the evolution of the damage in the composites.     

Investigation of some microstructural features related to corrosion initiation in titanium-aluminium nitride coated steel

In this work the microstructural features and defects identified previously in corrosion and porosity tests of the coatings were studied. The influence of surface roughness was evaluated with (Ti, Al)N coatings on two different types of substrates. Coatings deposited on the roughest surfaces on either a high speed steel or a stainless steel had the highest porosity. However, the dependence of the porosity on the surface roughness was not straightforward. Interrupted coating runs were carried out to obtain more information on the initiation of defects in the substrate-coating interface. Samples produced in the interrupted runs were analysed using metallographic methods, scanning electron microscopy with X-ray analysis, Rutherford backscattering spectrometry and secondary ion mass spectroscopy. Sputtering was found to be effective in removing the impurities from the interface and none of the non-metallic elements (carbon, oxygen, sulphur) studied exhibited any enrichment on the interface. The use of a tungsten filament for enhancement of the plasma was found to result in a tungsten-enriched layer at the substrate-coating interface, which may have an effect on adhesion and corrosion properties of the coating. However, no droplet types of formations were detected after sputter cleaning or when either titanium or aluminium evaporation was started, suggesting that tungsten was evenly distributed in the coating.     

功率对304L车板上激光熔覆Fe-Cr层组织和冲蚀性能的影响

在304L不锈钢车板上激光熔覆Fe-Cr层,通过实验测试的手段研究功率对其组织和冲蚀性能的影响。研究结果表明:对熔覆层进行熔覆过程中引起了组织晶化现象,逐渐提高功率后,晶体组织衍射峰也变得更加明显。经过0.5 kW以上功率的激光熔覆层中已基本观察不到层状组织,获得更致密的组织,实现了熔覆层和基体间的冶金结合作用。随着功率的增加,激光熔覆Fe-Cr层的密度表现出单调增加的变化规律。提高激光功率后,获得了更低硬度的熔覆层。通过喷涂工艺制得的熔覆层与基体间形成了机械结合的状态,使界面组织硬度发生快速降低,熔覆层的硬度呈现阶梯降低的变化规律。相对于304L不锈钢,熔覆层试样达到了更低体积磨损率。以更高冲击角进行处理时,可以使砂粒获得更集中的能量,从而更易在熔覆层中产生凹坑和裂纹,从而提高了体积损失率。     

化学气相沉积陶瓷复膜抗腐蚀试验研究

油气田开发过程中的井下腐蚀严重,由于腐蚀失效引起的损失极大地增加了油气田开发的成本。金属陶瓷具有很好的抗腐蚀性能,因此选择化学气相沉积(CVD)陶瓷复膜技术对井下工具进行表面处理以提高其抗腐蚀性能。选择油气田井下工具常用的钢作为实验对象,采用CVD法生成陶瓷复膜,通过抗应力腐蚀试验和电化学试验分析陶瓷复膜抗腐蚀性能,同时利用扫描电镜进一步分析陶瓷复膜抗腐蚀机理。实验结果表明:通过CVD陶瓷复膜的35CrMo具有很好的抗硫化氢腐蚀的能力。     

CVD nanocrystalline diamond coatings on Ti alloy: A synchrotron-assisted interfacial investigation

Diamond coating on Ti-6Al-4V alloy was carried out using microwave plasma enhanced CVD with a super high CH₄ concentration, and at a moderate deposition temperature close to 500 °C. The nucleation, growth, adhesion behaviors of the diamond coating and the interfacial structures were investigated using Raman, XRD, SEM/TEM, synchrotron radiation and indentation test. Nanocrystalline diamond coatings have been produced and the nucleation density, nucleation rate and adhesion strength of diamond coatings on Ti alloy substrate are significantly enhanced. An intermediate layer of TiC is formed between the diamond coating and the alloy substrate, while diamond coating debonding occurs both at the diamond-TiC interface and TiC-substrate interface. The simultaneous hydrogenation and carburization also cause complex micro-structural and microhardness changes on the alloy substrates. The low deposition temperature and extremely high methane concentration demonstrate beneficial to enhance coating adhesion strength and reduce substrate damage.     

金属镀层对铝/钢激光熔钎焊接头组织与性能的影响

针对在铝/钢焊接过程中,钢的表面金属镀层对铝/钢激光熔钎焊接头性能有着重要影响的问题,研究铝合金在不同金属镀层的低碳钢表面的铺展效果,通过SEM对不同金属镀层下熔钎焊接头界面微观组织形态、金属间化合物厚度、种类等进行分析,并进一步研究不同金属镀层下铝/钢接头的力学性能及断口形貌。结果表明:钢表面的金属镀层对铝/钢激光熔钎焊过程中5A06铝合金在钢上的铺展与浸润有着较大的影响,其中5A06铝合金在镀铝钢上的铺展效果最佳,且铝合金与镀铝锌钢熔钎焊的接头抗拉性能最好,达到母材铝合金的70%。铝/钢界面金属间化合物主要由铝铁金属间化合物组成,其中在镀铝钢、镀铝锌钢、镀锌钢中主要存在Fe2Al5,FeAl3,FeAl等金属间化合物,在镀镍钢界面中还存在Fe4Al13等金属间化合物。