聚苯胺/醇酸树脂复合涂料防腐性能的研究

制备了本征态聚苯胺(EB)/醇酸树脂复合涂料.通过Tafel极化曲线,探讨了EB含量对其防腐性能的影响,结果表明:当EB含量为3%(质量分数,全文同)时,复合涂料在3.5%NaCl溶液中的防腐性能较好,其腐蚀电位相应向正极方向移动了207 mV,并明显优于醇酸树脂涂料的防腐性能.     

阵列电极(WBE)联合线性极化技术(LP)研究海水-大气界面区碳钢的腐蚀行为

金属在海水-大气界面的水线腐蚀严重,腐蚀机理复杂,具有重要的科学研究价值。通过阵列电极(WBE)测试技术捕获部分浸泡于海水中的碳钢阵列电极的阴阳极分布规律;通过线性极化技术(LP)测试获得垂直于海水-大气界面的碳钢阵列电极列的腐蚀电流与腐蚀电位;通过电化学阻抗谱(EIS)与腐蚀形貌观察法相结合的方法探讨了垂直于海水-大气界面的碳钢阵列电极列的腐蚀机理差异。结果表明:垂直于海水-大气界面的碳钢分别在水线区域和近海水-大气界面的海水区域存在两个腐蚀峰,腐蚀峰的腐蚀电流是其他区域的3~10倍;大气中的腐蚀电位高于海水中,处于海水中的碳钢腐蚀电位随浸泡时间逐渐升高而处于大气中的腐蚀电位逐渐下降;海水中碳钢的腐蚀产物疏松、附着力差,在大气中则腐蚀产物致密、附着力强;海水-大气界面区碳钢的腐蚀是由电位差、溶解氧浓度、腐蚀产物等多因素控制的。     

碳／碳复合材料表面声电沉积磷灰石动力学研究

采用声电沉积技术，在碳／碳复合材料表面制备了生物活性磷酸钙涂层。扫描电镜、X射线衍射、红外反射以及X射线能谱分析表明所制涂层呈现网状结构，其由钙磷比为1．64、含碳酸根的羟基磷灰石组成。根据扫描电镜观察，描述了磷灰石的形成过程。羟基磷灰石的沉积过程可简化为两步——钙磷离子向碳／碳阴极表面运动和羟基磷灰石在碳／碳表面生长。基于此描述，导出了羟基磷灰石沉积动力学公式，并且发现，沉积过程受扩散控制，扩散活化能是30．3kJ／mol．     

钢材涂镀技术发展现状和趋势

介绍了钢材涂镀技术的进步,主要阐述了高强汽车用钢的涂镀技术,减量化耐腐蚀的新涂层的研发,特殊的功能涂层、绿色环保涂镀工艺的开发以及涂层材料耐蚀性能的评价方法.同时指出,我国涂镀钢板的品种、类型、性质、质量与国外尚有较大差距,应大力进行技术创新,以开发出具有我国特色的涂镀技术和涂层材料.     

核工业放射性固体废物包装容器防护涂料性能研究

针对用于中、低水平放射性固体废物包装容器,研究了以双酚A型环氧树脂为基料、以改性芳香胺为固化剂的防护涂层体系的性能.辐照实验、老化实验等测试结果表明,该涂料已完全达到了我国核行业有关标准中的技术要求.     

环氧涂层/碳钢间的界面化学键合研究

在环氧树脂E-44上接枝酒石酸对其改性,改性后的环氧树脂用来改善环氧涂层/碳钢间的界面附着力.红外光谱测试证明,改性环氧与碳钢表面发生化学键合.拉伸试验表明,改性后环氧涂层在金属表面的附着力得到明显的提升.     

钢-铝界面扩散层长大过程的研究

研究了液-固相轧制条件下钢．铝界面结合强度和扩散层的内部组织，分析了铝液温度和润湿时间对界面强度和扩散层厚度的影响，通过显微镜和电子扫描分析发现液．固相复合工艺制得的扩散层主要成分为FeA13，在钢板预热温度为250℃，加助焊剂的条件下，铝液温度为850℃时，大约3s后扩散层开始形成，而当铝液温度为。750℃时，扩散层的形成大约需要5s。在钢板温度为250℃，加助焊剂的条件下，铝液温度为850℃时，复合时间在8s-14s时界面剪切强度较高，而当铝液温度为750℃，复合时间在11s-17s时界面剪切强度较高。扩散层厚度在8pm-14μm之间时，界面剪切强度较高。     

高速钢／结构钢双金属复合材料界面研究

采用镶铸法,以液固结合的方式制备了高碳钡系高速钢/结构钢双金属复合材料。研究了不同结合条件下,双金属复合材料界面结构及形态。试验结果表明,镶铸是靠外层合金带入的过热热量来获得界面结合的,当外材与芯材在体积比大于8.0的条件下,才有可以获得界面结合,其界面结合为扩散结合,复合材料界面结构由芯材扩散层,激冷凝固层、方向性生长层和胞状晶粒层组成,外层材料凝固时有明显的方向性生长,其液固相线推移速度对在液固结合条件下外层材料的凝固组织具有明显影响,当外材与芯材体积比为1.25时,外层材料的凝固速度最快,出现了棒状伪共晶组织,随体积比的增长,凝固组织表现为沿径向传热方向拉长的胞状晶粒。     

碳钢管内表面化学镀Ni-P耐蚀层的研究

为了在Q235钢管内表面制备Ni-P化学镀层,以提高普通碳钢管道的耐蚀性,通过正交试验研究化学镀的镀液配方,并检测镀层的化学成分及其在盐水中的耐蚀性。研究表明:Q235钢管内表面制得的Ni-P化学镀层最佳配方为硫酸镍7.6×10~(-2)mol/L,次亚磷酸钠0.17 mol/L,柠檬酸钠3.4×10~(-2)mol/L,硫脲1.32×10~(-5)mol/L;镀层沉积速率为25.4μm/h,镀层硬度为747 HV;镀层中Fe、Ni和P元素的质量百分比分别为0.89%、85.63%和13.48%;在3.5%的NaCl溶液中镀层的自腐蚀电位为-0.62 V(SCE),自腐蚀电流密度为5.82×10~(-6)A/cm~2,比Q235钢的自腐蚀电流密度降低了98.1%。     

C/C复合材料SiC-TaSi2/MoSi2抗氧化复合涂层研究

采用包埋技术在C/C复合材料表面制备SiC-TaSi2/MoSi2抗氧化复合涂层,通过恒温氧化实验以及X射线衍射(XRD)分析、扫描电镜(SEM)观察及能谱(EDS)分析,研究了包埋粉料中Ta,Mo含量对复合涂层微观结构和高温抗氧化性能的影响.结果表明,Ta,Mo摩尔比为1:1时所制备的复合涂层具有相对较大的厚度和较为致密的结构,氧化过程中在该涂层表面形成致密和稳定的玻璃态SiO2保护膜.在1500℃氧化326 h和经过23次1500℃至室温间的急冷急热后,带有该涂层的C/C试样失重仅为0.97%,表明该涂层具有优异的抗氧化和抗热震性能.     

Ni基自熔合金涂层与钢基材的界面形态及其作用

对采用氧 -乙炔火焰喷焊、等离子喷涂后氧 -乙炔火焰重熔与等离子喷涂后炉内重熔三种工艺制备的WC增强Ni基自熔合金涂层与 38CrMoAl钢基材的结合界面形态的研究表明 ,在涂层熔化过程中 ,涂层与基材之间发生成分的互扩散 ,以基材中的元素Fe向熔融涂层中的扩散为主 ,其扩散程度对涂层与基材能否形成良好的冶金结合具有决定性的影响。当结合界面处的基材表层温度足够高时 ,基材中的元素Fe向涂层中的扩散量较大 ,扩散距离较长 ,在界面处就能够形成致密完整的Fe -Ni单相固溶体组织白亮层 ,使涂层与基材获得很高的结合强度     

金属腐蚀微区电化学研究进展(3) 扫描振动电极技术

近年来,随着微区电化学理论与测试技术的发展,微区电化学技术在腐蚀领域已作为一种重要的测试方法被广泛应用,本文概括了扫描振动电极的基本原理,重点对该技术在金属腐蚀研究领域的应用进行了阐述。     

Study of Scanning Micro-arc Oxidation and Coating Development

Micro-arc oxidation (MAO) continues to be the focus of numerous investigations, whereas relatively few studies have considered scanning micro-arc oxidation (SMAO). In the present work, an experimental study was performed using stationary and moving electrodes to investigate coating development in SMAO and discern the effect of key process parameters. Examination of oxide deposits made on A356 aluminum show that coating thickness and growth rate are inversely related to inter-electrode spacing and travel speed. An evaluation of SMAO deposits made by stationary and moving nozzles revealed that coating thickness profiles follow a Gaussian distribution due to the electrolyte flow field in the impingement zone. Hardness surveys and scanning electron microscope analysis of SMAO coatings revealed that micro-hardness distributions and cross-sectional morphology are similar to MAO for a stationary nozzle but that a denser outer layer develops when a moving nozzle is used. This is attributed to a high density of discharge occurring in micropores of the oxide film and remelting which results from the moving electrolyte column. Analysis of voltage–current characteristic curves shows that the resistance of the electrolyte column is essentially linear over the range considered and results indicate that it can be modeled as a variable length resistor. While further testing is needed, results confirm that SMAO is suitable for coating large, planar parts and for repairing worn surfaces.     

Welding Heat Input Influence on UNS S82441 Lean Duplex Stainless Steel Corrosion Resistance Assessed by Scanning Vibrating Electrode Technique (SVET)

The precipitation of the intermetallic phases can impair mechanical and corrosion properties. In the case of lean duplex stainless steels, they present solidification mode as primary ferrite, with austenite precipitation in the solid state, during cooling. This means the heat-affected zone balanced microstructure can be changed during the welding by the cooling rate, which is associated to the welding heat input, the thickness of the plate and the physical properties of the material. This work intends to present the influence of welding heat input on the corrosion resistance of UNS S82441 lean duplex stainless steel. The gas metal arc welding process was used to make the weld beads, using ER2209 as filler metal, which characterizes a dissimilar welded joint. The corrosion resistance of these specimens was analyzed through scanning vibrating electrode technique. It was observed that welding heat input variation distinctly influences corrosion in different zones of the weld beads over the specimen exposure time. The weld bead under intermediate welding heat input showed the highest corrosion rate and the one under the highest welding heat input, the lowest corrosion rate intensity.     

铸造烧结TiC钢结硬质合金/多元低合金钢复合界面及组织的研究

在研究烧结坯体压制工艺和铸造烧结工艺的基础上,采用铸造烧结法在多元低合金钢基体上,复合了2～4mm厚的铸造烧结TiC钢结硬质合金层.利用扫描电子显微镜和XRD等方法研究了烧结结合界面以及复合层组织和成分.结果表明:铸造烧结TiC钢结硬质合金复合层与基体材料结合界面存在明显的过渡层,为冶金结合;铸造烧结层中硬质相主要为TiC颗粒,其形状近似球形,颗粒直径在0.5～2 μm,体积分数约为50％～60％,均匀分布在粘结相中;粘结相为Fe-Cr的固溶体,含有少量Cr3C2和Cr7C3等烧结过程中形成的碳化物.     

低碳钢表面热浸镀锌层的组织

利用传统的溶剂工艺在低碳钢表面热浸镀锌。采用X射线衍射仪和扫描电镜研究了低碳钢热浸镀锌层的显微组织及相组成。结果表明,热浸镀锌层的组织由基体向表面依次为Γ(Fe5Zn21)相、1δ(FeZn7)相、ζ(FeZn13)相和η(Zn)相;镀层最表层出现异常的Γ相,而1δ相合金层存在η相;与基体结合处的Γ相呈白亮的线状,靠近表面则呈齿状;镀层不同部位的块状1δ相的致密度不同,远离基体处比较疏松;棒状ζ相分散在η相中。     

Study of the Splat-Substrate Interface for a PEEK Coating Plasma-Sprayed onto Aluminum Substrates

The quality of coatings made using thermal spray processes depends greatly on the degree of adhesion between the substrate and its coating. Yet the bonding mechanisms between a substrate and coating are not well understood. In this study, polyetheretherketone (PEEK) powder was plasma-sprayed to form single splats on aluminum substrates, which had undergone various surface treatments, including boiled (BT), etched (E, ET), and polished (PT), all of which had also been thermally treated to remove water from the substrate surface, with the exception of one etched aluminum substrate. Scanning electron microscopy was used to give an overview of the surface and splat morphology. The splat-substrate interfaces were studied in detail using focused ion beam imaging and transmission electron microscopy, to characterize microstructural features within the splat-substrate interface, including inter/intrasplat pores, pores along the splat-substrate interface, level of contact between the splat and the substrate, etc. The results showed that the splat-substrate interface for the BT and the E substrate surface had poor level of contact, with a high number of small pores (<1 μm) along the splat-substrate interface for the BT splat-substrate interface, and the formation of a near-continuous crevice between the PEEK splat and the aluminum substrate for the E substrate surface. The presence of the fine needle-like network of oxide layer on the BT substrate surface may have restricted the flow of the molten PEEK on the aluminum substrate, and the possible presence of physisorbed and chemisorbed water on the E substrate surface may have reduced the level of contact between the PEEK and the aluminum substrate. In contrast, specimens which had undergone thermal treatment to minimize the presence of water on the substrate surface, such as the ET and PT substrate surface, exhibited high level of contact at the splat-substrate interface. The number of pores for the ET and the PT splat-substrate interfaces were substantially lower than of the BT and E splat-substrate interface.     

碳钢件消失模水基涂料的研制

选用高铬刚玉耐火骨料，氧化淀粉和硫酸铝为粘结剂，通过正交试验，确定了碳钢铸件消失模水基涂料的最佳配比，考察了涂料的多种性能，并进行了生产应用。     

碳钢表面防腐超疏水TiO_2/PDMS涂层的制备及性能

针对碳钢腐蚀电位相对更负、更容易发生腐蚀的特点,在Q235钢表面制备超疏水TiO_2/PDMS涂层以提高其耐蚀性能。采用表面活性剂分散纳米TiO_2并进行改性,然后与PDMS混合,用溶胶凝胶法在Q235钢表面制备有聚二甲基硅氧烷(PDMS)过渡层的TiO_2/PDMS超疏水涂层。借助扫描电镜(SEM)、接触角测量仪、红外光谱(FT-IR)及X射线衍射仪(XRD)表征其表面涂层的表面形貌、化学成分及疏水性能,用电化学试验和浸泡试验测试其防腐性。结果表明:TiO_2/PDMS涂层表面具有独特的微纳结构,与水的接触角达到154.3°;其腐蚀电位由碳钢的-0.77 mV正移至超疏水涂层的-0.24 mV,腐蚀电流密度则下降两个数量级,即从5.02×10~(-6)A·cm~(-2)下降至3.95×10~(-8)A·cm~(-2);超疏水涂层的交流阻抗值高于碳钢基底3个数量级。经过7 d的3.5wt.%NaCl溶液浸泡,超疏水涂层并未发生失重。制备的TiO_2/PDMS超疏水涂层具有超疏水效果和良好的长期耐腐蚀性。