腐蚀介质对复合材料界面影响的模型研究

为阐明界面对复合材料耐腐蚀性能的影响,本文作者采用单丝模型研究了偶联剂处理对复合材料界面粘接能和耐腐蚀性能的作用。实验证明:单丝模型中单丝直径与界面粘接能无关;硅烷偶联剂处理液浓度对玻纤表面处理效果有很大影响:界面上化学吸附的及与玻纤表面起化学作用的偶联剂层对改善界面粘接起主要作用:对玻纤进行适当的表面处理能大大改善界面耐腐蚀性能。     

环氧铝粉涂层在3.5%NaCl介质中的失效机理研究

采用电化学阻抗谱技术（EIS）研究了环氧铝粉涂层/Q235钢基体在3.5 %NaCl介质中的电化学腐蚀行为.利用扫描电镜（SEM）分析了涂层表面形貌,对涂层断面进行了能谱（EDX）线扫描和界面处腐蚀产物成分分析,探讨了环氧铝粉涂层的腐蚀失效机理.结果表明,腐蚀介质能通过涂层迅速渗透到涂层/基体界面,引起涂层电阻值的降低及界面处电化学腐蚀的开始.失效前涂层致密、连续,失效后涂层表面出现鼓泡、孔洞等现象.鼓泡是由腐蚀产物的体积膨胀和腐蚀介质渗入产生的压力推动共同产生的.界面处腐蚀产物主要是Fe和Al的氧化物及氯化物.涂层的失效机理为腐蚀介质渗入,涂层鼓泡、剥离.     

表面镀钨层对金刚石/铜复合材料热导率的影响

采用真空微蒸发-扩散镀技术,在金刚石表面镀覆不同厚度的钨层,并结合真空熔渗法制备金刚石铜复合材料。通过X射线衍射分析镀覆层相结构,采用扫描电镜观察镀覆层表面微观形貌和复合材料中金刚石与铜界面结合形貌,分析金刚石表面镀钨层组织、结构及厚度对金刚石/铜复合材料热导率的影响。结果表明:金刚石表面镀覆钨能改善与基体的润湿性;随着镀覆层均匀性和厚度增加,复合材料热导率先增加后减小;完整均匀的镀覆层可以获得较高界面热导。     

玻璃纤维表面的聚甲基丙烯酸甲酯接技

1 引言 复合材料是由基体树脂和增强剂构成的多相材料,基体和增强剂的界面结合状态对复合材料的性能有重要影响,复合材料界面是复合材料科学中一个十分活跃的研究领域。 对热固性树脂基复合材料已发展了比较成熟的玻璃纤维表面处理技术,如用硅烷偶联剂处理玻纤,使玻纤和基体树脂通过偶联剂实现化学键结合,复合材料性能显著提高。     

碳纤维和芳纶纤维的蚀刻改性及其复合材料界面结合性能研究进展

纤维作为复合材料中的增强体,在实现应力传递、承担外部载荷等方面发挥了重要作用.通常纤维与树脂基体的结合性能极大地取决于纤维表面的微观形貌和化学性质,其界面结合的强度则决定了复合材料的综合性能和应用范围.为了最大提升纤维材料与树脂基体的界面结合能力,在应用前需对纤维材料进行有效的表面改性处理.其中,蚀刻法同时涉及了纤维表面的物理变化和化学变化,具有高效的表面改性能力,能显著地改变纤维表面的物理化学性质.综述了表面蚀刻这一改性思路分别在碳纤维和芳纶纤维中的实际应用,针对两种纤维各自的性质,提出了酸性溶液蚀刻、有机溶液蚀刻、电化学阳极氧化、等离子体处理、微波辐射、超声波蚀刻等常用蚀刻改性方法,对各方法的优缺点和应用进行了讨论.总结并对比了蚀刻介质、蚀刻工艺对纤维表面微观形貌、化学性质、力学性能以及复合材料界面结合性能等方面的影响.讨论了当前纤维材料与树脂基体界面结合的机理与界面表征方法的研究现状.此外,还对未来的发展方向和要求进行了展望,提出应该聚焦纤维表面腐蚀行为,优化传统改性方法,开发多种方法协同作用的改性新工艺.同时基于现有技术,发展更为先进的界面表征手段,进一步加深对纤维表面腐蚀行为与复合材料界面性能之间影响机制的理解.     

专利集锦

<正>一种表面分级复合材料界面层及其制备方法申请公布号:;申请公布日:2014.10.08;申请号:申请CN104087932A 2014102647923;日:.06.申请人:大连理工大学;发明人:雷明凯。2014 14;一种表面分级复合材料界面层及其制备方法,属于材料表面工程技术领域。该表面分级复合材料界面层由分散的硬质第二相和包覆的金属粘结相的表面复合材料组成,表面分级复合材料界面层为一具有分级结构的硬质第二相次级单元构成的表面复合材料,电火花放电采用硬质第二相     

等离子处理及固化方式对碳纤维复合材料动态力学性能的影响

采用低温氨气等离子法对碳纤维进行表面处理,分别在室温和微波固化条件下将碳纤维与环氧树脂复合成型,制备出碳纤维复合材料.X射线光电子能谱和原子力显微图像分析表明,对碳纤维进行表面处理后,碳纤维表面羧基、氨基官能团含量和表面粗糙度增大,对复合材料界面粘结效果影响明显.动态热机械分析法测试结果显示,微波固化15 min与室温固化1天成型复合材料相比,阻尼因子tanδ低,玻璃化转变温度Tg高,界面粘结效果更优,常温玻璃态储能模量E'由室温固化的6.5 GPa提高到微波固化的10.9 GPa.微波固化成型技术可在短时间内获得界面粘结效果良好的复合材料.     

纳米二氧化钛浓缩浆对硼酚醛环氧涂料性能的影响

目的提高硼酚醛环氧涂料的耐腐蚀性、表面接触角、粘结强度及耐磨性等。方法用纳米二氧化钛浓缩浆改性硼酚醛环氧涂料,制备耐温耐蚀型纳米复合涂料。通过高温高硫原油浸泡试验评价纳米复合涂层的耐腐蚀性能,通过扫描电镜观察、表面接触角测试、粘结强度测试和耐磨性测试等手段分析纳米二氧化钛浓缩浆对涂层性能的影响。结果硼酚醛环氧纳米复合涂层在100℃高硫原油腐蚀浸泡后,微观上没有出现腐蚀坑和裂纹。添加2%纳米二氧化钛浓缩浆的硼酚醛环氧纳米复合涂层与未添加纳米粒子的硼酚醛环氧涂层相比,抗渗性与耐磨性有所提高。720 h腐蚀试验后,纳米复合涂料的粘结强度由试验前的7.7 MPa降低至6.9 MPa。腐蚀过程中,其表面接触角比非纳米涂层高4°~7°。结论高温高硫原油没有破坏硼酚醛环氧纳米复合涂层的形貌结构、粘结强度和耐磨性。添加2%纳米二氧化钛提高了涂层的抗渗透性和表面接触角。     

金属基复合材料液态成形中界面粘结的增强措施

金属基复合材料液态成形要涉及到金属与增强物的润湿、吸附、反应等界面粘结现象,这直接关系到复合材料的质量及性能。本文讨论了与界面粘结有关的这些表面现象以及改善液态金属与增强物界面粘结的工程措施。     

SiC纤维表面去碳处理对PIP-SiCf/SiC复合材料力学性能以及界面影响

采用强度测试、SEM、HRTEM等分析测试手段对纤维表面去碳前后SiC纤维强度、复合材料力学性能、纤维表面形貌、复合材料断口形貌以及复合材料界面特征进行分析表征.结果表明,去碳处理后,纤维表面的固有缺陷暴露出来,纤维强度下降约15%,但由其制备的复合材料强度下降只有原纤维制备复合材料的1/6;复合材料断口非常平整,纤维...     

Role of Powder Granulometry and Substrate Topography in Adhesion Strength of Thermal Spray Coatings

APS coating is deposited with different treated surfaces to understand the effects of surface topography and particle sizes on adhesion bond strength. Grit blasting and laser surface texturing have been used to create a controlled roughness and controlled surface topography, respectively. Coating adhesion is mainly controlled by a mechanical interlocking mechanism. Fully melted Ni-Al powder fills the respected target surface with high-speed radial flow. Pores around central flattening splat are usually seen due to splash effects. Laser surface texturing has been used to study near interface coating depending on the target shape and in-contact area. Pull-off test results have revealed predominant correlation with powder, surface topography, and adhesion bond strength. Adhesion bond strength is linked to the in-contact area. So, coating adhesion might be optimized with powder granulometry. Pores near the interface would be localized zones for crack initiations and propagations. A mixed-mode failure has been reported for sharp interface (interface and inter-splats cracks) due to crack kicking out phenomena. Coating toughness near the interface is a key issue to maximize adhesion bond strength. Volume particles and topography parameters have been proposed to enhance adhesion bond strength for thermal spray process for small and large in-contact area.     

海洋风电重防腐涂料环氧玻璃鳞片的性能研究

目的研究重防腐涂料环氧玻璃鳞片耐蚀耐磨性能。方法对环氧玻璃鳞片与其它3种环氧类涂层进行磨耗实验,通过紫外线老化、低温暴露和盐雾等系列力学和耐腐蚀性能检测,研究环氧玻璃鳞片的耐腐蚀性能。结果各涂层都符合磨损性能指标(1000转的磨耗量小于1.8 g),环氧玻璃鳞片的耐磨性比环氧树脂涂层较差,但是比另外两种环氧类涂层耐磨性都好;耐蚀循环2400 h后,4种不同环氧类涂层表面均出现粉化、锈点,变色明显;环氧玻璃鳞片的结合力好于其他3种达到6.7 MPa,并且划线处的起泡数目最少,单边扩蚀只有2.5 mm,失光率最小。结论环氧玻璃鳞片涂层中由于鳞片的层状分布,延缓了腐蚀介质的渗透,具有良好的耐磨耐蚀性能,可以作为一种高效的重防腐涂料,应用于海洋、船舶等环境中。     

Numerical Investigation of the Macroscopic Mechanical Behavior of NiTi-Hybrid Composites Subjected to Static Load–Unload–Reload Path

Shape memory alloys (SMAs) are a type of shape memory materials that recover large deformation and return to their primary shape by rising temperature. In the current research, the effect of embedding SMA wires on the macroscopic mechanical behavior of glass–epoxy composites is investigated through finite element simulations. A perfect interface between SMA wires and the host composite is assumed. Effects of various parameters such as SMA wires volume fraction, SMA wires pre-strain and temperature are investigated during loading–unloading and reloading steps by employing ANSYS software. In order to quantify the extent of induced compressive stress in the host composite and residual tensile stress in the SMA wires, a theoretical approach is presented. Finally, it was shown that smart structures fabricated using composite layers and pre-strained SMA wires exhibited overall stiffness reduction at both ambient and elevated temperatures which were increased by adding SMA volume fraction. Also, the induced compressive stress on the host composite was increased remarkably using 4% pre-strained SMA wires at elevated temperature. Results obtained by FE simulations were in good correlation with the rule of mixture predictions and available experimental data in the literature.     

Arrest,deflection, penetration and reinitiation of cracks in brittle layers across adhesive interlayers

A layer structure consisting of two glass plates bonded with polymer-based adhesives and loaded at the upper surface with a line-wedge indenter is used to evaluate crack containment. Two adhesives are used, a low-modulus epoxy resin and a particle-filled composite. The adhesives arrest indentation-induced transverse cracks at the first interface. A substantially higher load is required to resume propagation beyond the second interface in the second glass layer. Delamination is not a principal failure mode. Nor is the operative mode of failure one of continuous crack penetration through the adhesive, but rather reinitiation of a secondary crack in the glass ahead of the arrested primary crack. A fracture mechanics analysis, in conjunction with finite element modeling, is presented to account for the essential elements of crack inhibition, and to identify critical material and layer thickness variables. It is confirmed that adhesives with lower modulus and higher thickness are most effective as crack arresters.     

氨基链修饰氧化石墨烯/环氧树脂界面性能的分子动力学模拟

目的 对氨基链修饰氧化石墨烯与DGEBA/3,3′-DDS环氧树脂复合材料界面的形成过程和性能进行理论研究,为环氧树脂涂层的性能改性提供理论依据.方法 利用Materials Studio 2019软件的Amorphous Cell模块建立了复合材料界面模型,采用分子动力学模拟方法对界面的结构、能量变化、界面处基团运动...     

聚脲涂层体系在混凝土表面的附着性能研究

应用无溶剂环氧封闭涂料和聚脲涂料在混凝土试样表面制备聚脲涂层体系,测试了该涂层体系在混凝土表面的附着强度,利用表面形貌分析及红外光谱和电子能谱等技术手段,分析混凝土与聚脲涂层界面特性,探讨聚脲涂层在混凝土表面附着失效的机理。结果表明,聚脲涂层与混凝土的附着失效为涂层与混凝土之间的物理附着破坏;而无溶剂环氧封闭涂层+聚脲涂层体系的失效为封闭涂层与混凝土之间的物理附着破坏和封闭涂层本身的内聚破坏;封闭涂层的应用可提高混凝土表面的强度,无溶剂环氧封闭涂层和聚脲涂层之间可以形成互穿网络结构。     

TiO2 / 玻璃鳞片复合颗粒的制备及抗渗透性能研究

目的制备TiO2/玻璃鳞片复合颗粒以改善玻璃鳞片与涂层的界面性能,提高复合涂层的抗渗透能力。方法利用溶胶回流法在玻璃鳞片表面制备一层TiO2薄膜,通过SEM,EDS以及XPS等技术表征TiO2薄膜的表面状态。制备复合涂层,利用EIS和盐雾试验测试TiO2/玻璃鳞片的抗渗透能力,并与玻璃鳞片的抗渗透性进行对比。结果玻璃鳞片表面被TiO2薄膜包覆,TiO2薄膜与玻璃鳞片表面以Si—O—Ti化学键连接,浸泡15 d后,玻璃鳞片涂层的Zw为8781Ω,TiO2/玻璃鳞片涂层的Zw为75234Ω。盐雾试验后,TiO2/玻璃鳞片涂层下的金属几乎没有腐蚀。结论玻璃鳞片经过TiO2包覆后,具有较强的抗渗透能力。     

A model for predicting micromechanical interfacial adhesion in polymer composites

The mechanical behavior of fiber-reinforced composites is largely determined by adhesion at the fiber-matrix interface. Thus, a fundamental understanding of the interfacial region and a quantitative characterization of the level of interfacial adhesion can contribute to an evaluation of the mechanical behavior and performance of composite materials. Among numerous techniques for interface characterization, the vibration damping method has attracted continually more attention because it provides sensitive and nondestructive detection of the interfacial region in composites. In the research presented here, a new optical system for measuring vibration damping was introduced, and a model for evaluating the interfacial adhesion between fiber and matrix from a damping parameter was developed. A quantitative relationship between the dynamic (vibration damping) and static (interfacial shear strength) adhesion measurements was established. The experimental data from glass-fiber-reinforced epoxy resin composites with different interfacial treatments showed good agreement with the theoretical model.     

PECVD low-permittivity organosilicate glass coatings: Adhesion,fracture and mechanical properties

The structure and mechanical behavior of organosilicate glass (OSG) coatings have been analyzed as a function of composition and UV irradiation time. A decrease in the OSG carbon content results in more networking bonds and increased connectivity; UV irradiation increases the connectivity by severing weak terminal bonds and stabilizes the network through local bond rearrangements. These structure modifications lead to a significant improvement in the stiffness, hardness, and fracture energy of these coatings. The networking bond density and mean connectivity number correlate well with the mechanical behavior of the OSG films, although network bond density weighted by bond energy is a more appropriate measure. The adhesion energy of silicon nitride to OSG is significantly higher than the cohesive energy of the OSG as a result of interface densification and crack-tip shielding. Subcritical fracture measurements in aqueous environments show that the detrimental effect of water on adhesion surpasses the effect of network connectivity.     

The Role of Stitch Yarn on the Delamination Resistance in Non-crimp Fabric: Chemical and Physical Interpretation

In a 3D preform, the out-of-plane reinforcement is effective for decelerating or suppressing the delamination process as the non-crimp fabric does not connect the neighboring laminae effectively. Hence, the interlaminar strength of the stitched laminae is supposed to behave in the same way as a regular unidirectional composite. In order to determine whether or not the stitched yarns contribute to the interlaminar fracture toughness, this study determinated the delamination resistance of a quasi-isotropic laminate. The analysis was based on interlaminar fracture toughness (G _Ic) and propagation energy curve in tests conducted in mode I opening with double cantilever beam specimen geometry. The results of fracture toughness as well as strain energy for propagation were compared to their fracture surface. A decrease in the propagation energy prevailed in the surface because the stitch yarn replaced the carbon fiber/epoxy interface, which has better chemical affinities, i.e., covalent bonds.