石墨烯基超疏水材料制备及其应用研究进展

超疏水表面是具有独特性能的一类表面,本身就具有广泛应用前景。石墨烯材料作为理化性质出众的一类材料,由于其高电导率、高导热系数、高比表面积、高透光率和有优异的机械性能,广泛应用于航空航天、石油化工、海洋船舶等领域。目前,基于石墨烯材料构建超疏水表面,是超疏水表面研究中一个较新的方向。本文对超疏水表面的原理进行了概述,重点总结归纳了石墨烯基超疏水材料制备技术的研究现状,包括表面修饰法、沉积改性法、激光诱导法、涂覆法、层层自组装法等,简要介绍了石墨烯超疏水材料在自清洁、油水分离、防覆冰、耐腐蚀、抗菌等领域的应用,并对石墨烯超疏水材料的下一步研究方向进行了展望。      

工业化超疏水TiO_2涂层的简易制备和性能研究

为探究适合工业化生产用超疏水纳米TiO_2的绿色改性工艺,以饱和脂肪酸A、硅烷B、纳米TiO_2(P25)等为原料制备超疏水TiO_2粉末,与环氧树脂混合后利用喷涂法制备出超疏水涂层。采用扫描电子显微镜、X射线衍射仪、傅里叶变换红外光谱仪和接触角分析仪对超疏水粉末和超疏水涂层表面的形貌和疏水性进行了表征。结果表明:超疏水TiO_2粒子表面具有疏水性基团和微-纳米双重粗糙结构,粒子表面的静态水接触角为158°,滚动角为3°;当超疏水TiO_2与环氧树脂的质量比在3.2～3.5时,超疏水涂层既保持超疏水性,又与基底稳固结合,同时具有自清洁性和可修复性。该工艺操作简单方便,成本低,疏水性好,无需特殊设备,工艺环保,适应工业化生产,可用来大面积制备超疏水涂层,拥有较高的商业价值。     

TiO_2纳米颗粒自清洁航空涂料的性能研究

以有机硅改性聚氨酯树脂为主要成膜物质,经氟硅烷进行表面改性后的TiO2纳米颗粒作为无机填料,制备具有自清洁功能的航空涂料。利用透射电镜(TEM)、X射线光电子能谱仪(XPS)、扫描电镜(SEM)及接触角分析仪对氟硅烷的改性机制进行了分析,讨论了改性TiO2纳米颗粒的用量对涂层疏水性及其力学性能的影响,探讨了表面微观结构和涂层疏水性能之间的关系,并分析了有效改善涂层力学性能的技术途径。结果表明,氟硅烷分子水解后相互联结,在TiO2纳米颗粒表面形成一层氟硅烷分子包覆层,提高了TiO2纳米颗粒的分散性及疏水性。随着氟硅烷改性后的TiO2纳米颗粒添加量逐渐增多,制备的有机涂层表面粗糙度逐渐增大,疏水效果越来越明显。当改性TiO2纳米颗粒的用量为24%时,涂层具有超疏水性,水接触角为151.40°,涂层表面为微纳米双重粗糙结构。通过在基底表面刷涂一层质量分数为5%~15%的硅烷偶联剂(KH-550)乙醇溶液,可以提高涂层的力学性能,达到航空涂料的基本使用要求。     

超疏水表面功能材料研制成功

近日,中国科学院兰州化学物理研究所（简称兰化所）研究人员利用简便、经济、实用的复合有机涂层材料制备方法,于铝、铜、钢等金属材料表面构筑出了具有微／纳米结构的超疏水表面功能涂层材料,解决了超疏水涂层材料在工程应用中构筑方法复杂、工程实用困难的关键技术问题。项目研究组利用聚四氟乙烯和聚苯硫醚复合聚合物采用一步成膜法构筑出的表面同时具备低表面能疏水基团及多孔网络微纳米结构的超疏水涂层。     

铝合金类水滑石/微弧氧化复合膜层的超疏水及耐蚀性能

为解决铝合金表面耐蚀性差的问题,采用两种方法在铝合金表面制备一种复合膜层。首先利用微弧氧化(MAO)技术在铝合金表面原位生长陶瓷层。然后利用化学方法在陶瓷层表面原位生长出类水滑石薄膜(LDH)。最后利用硬脂酸对复合膜层进行表面修饰,以达到超疏水表面。利用扫描电镜(SEM)、 X射线衍射(XRD)、接触角测量仪及电化学工作站分别分析了微弧氧化陶瓷层及复合膜层的表面形貌、物相结构、疏水性以及耐腐蚀性能。结果表明:类水滑石片层物将微弧氧化陶瓷层的缺陷(微孔及微裂纹)完全封闭,并且制备的复合膜层构建出了微/纳二元结构。经表面修饰剂修饰后复合膜层的接触角为155.2°,而微弧氧化陶瓷层的接触角为17.5°。利用电化学工作站测试的极化曲线结果显示,超疏水复合膜层的腐蚀电流密度比微弧氧化陶瓷层降低了约两个数量级;而阻抗图谱分析表明,超疏水复合膜层具有更优异的耐蚀性。     

钛合金表面激光熔覆固体自润滑涂层

综述了激光熔覆技术在钛合金表面制备固体自润滑涂层的研究现状。采用激光熔覆技术可以在钛合金表面制备出具有优异减摩性能的固体自润滑涂层,其减摩效果与所选用的激光器、熔覆材料的成分配比、添加剂的添加方式等有密切关系。最后指出了今后该技术的发展方向:1开发高水平的激光熔覆设备;2开发新型熔覆材料体系,使其能应用于不同的环境和很宽的温度范围中;3开发多层涂层、智能涂层(如自修复功能)和梯度涂层;4对激光表面熔覆处理过程进行数值模拟,实现激光熔覆过程的定量控制。     

粉末粒径对真空等离子体喷涂钛涂层的影响

粉末粒径是影响等离子体喷涂涂层结构和性能的主要因素之一。本文采用四种不同粒径分布的钛粉,通过真空等离子体喷涂（VPS）工艺在不锈钢基体上制备了粗糙多孔的钛涂层,研究了粉末粒径与钛涂层表面粗糙度、气孔率和结合强度间的关系。结果表明：在粉末熔融状况良好的情况下,不同粒径分布的钛粉制备的涂层结构均较均匀;钛涂层的表面粗糙度和气孔率随粉末粒径的增大而增大,涂层结合强度随粉末粒径增大而减小。     

PECVD法原位渗氮表面改性钛双极板的性能

为了提升钛双极板的导电性和耐腐蚀性,利用氮气等离子体原位渗氮法对钛片（TA2）进行表面改性,制备了系列氮化钛涂层,系统研究了反应温度和渗氮时间对涂层表面形貌、疏水性、界面导电性和耐腐蚀性的影响。结果表明,温度过高会导致氮化钛生长过快,颗粒尺寸较大;温度较低不利于表面反应,涂层不能完全覆盖钛基底;渗氮时间较短,表面生成不规则的纳米生长核,致使涂层不平整、钛基底裸露;渗氮时间过长,涂层呈阶梯堆垛状,平整度降低。650 °C下渗氮90 min制备的氮化钛涂层（TiN-650-90）均匀平整,组成为TiN_0.26;TiN-650-90的水接触角提升至105.4°,表面疏水性有利于改善燃料电池的水管理性能;界面接触电阻（ICR）随加载压力增大而降低,2.75 MPa时TiN-650-90的ICR稳定至6.5 mΩ·cm2,满足美国能源部（DOE）要求（≤10 mΩ·cm2）;TiN-650-90的腐蚀电流密度为0.56 μA·cm–2,–0.1 V恒电位下的电流密度为0.67 μA·cm–2,耐腐性和稳定性较钛的明显提升。该方法制备氮化钛涂层表面改性钛双极板,具有沉积温度低、速度快,疏水性、导电性和耐腐蚀性优良等优点,可为金属双极板表面改性提供方法借鉴和工艺参考。      

Ti/TiO_2/BGC生物活性复合材料的制备及其性能研究

以纯钛金属为基体,采用阳极氧化法在钛基体表面原位生长TiO_2纳米氧化层,采用溶胶凝胶法在TiO_2纳米氧化层表面涂覆生物活性微晶玻璃涂层(BGC)。通过扫描电镜(SEM)、X射线衍射仪(XRD)、涂层附着划痕试验、人体体液模拟试验,分析BGC涂层的形貌和物相,评价涂层的生物活性,研究不同摩尔分数的CaF_2对涂层结合力的影响规律。结果表明:引入TiO_2微纳米氧化层后,材料表面的接触角变小,亲水能力提高,钛基体与涂层之间的结合力提高了27%左右;当CaF_2摩尔分数为4%时,钛基体与涂层之间的结合力最大为64 N;Ti/TiO_2/BGC复合材料在模拟体液中浸泡7 d后,材料表面生成大量的羟基磷灰石。     

拉伸变形对高熵合金激光涂层组织和性能的影响

采用激光熔覆设备在不锈钢片和40Cr钢表面制得Al2Co Cr Cu0.5Fe Mo Ni Ti高熵合金涂层,对涂层进行退火和拉伸变形,并采用X射线衍射仪、扫描电子显微镜和显微硬度计对涂层进行测试。结果表明,熔覆涂层经过抛光和王水腐蚀后,显微形貌为胞粒状特征。300℃退火对涂层硬度没有影响;500~700℃退火后,涂层硬度提高,说明涂层具有时效硬化效应。涂覆态涂层由bcc单相组成,300℃退火后,涂层保持稳定的相结构。拉伸变形后,涂层的衍射峰强度增加,晶界清晰;硬度则随变形量增加先降低后提高。涂层具有良好的附着性能,除了断口附近出现涂层脱落外,其他位置的涂层都保持良好的附着状态。     

Superhydrophobic and anti-icing properties of sol–gel prepared alumina coatings

Sol–gel is a convenient method to fabricate micro-nano structures on various surfaces. In the present study, rough alumina surfaces were prepared from aluminum isopropoxide and ethyl acetoacetate and modified with low-concentration lauric acid (LA) dissolved in ethanol. The sample hydrophobicity and antiicing property were optimized by changing the rotation speed, rotation time, and coating thickness during spin-coating, and the type and concentration of surface modifier used during surface hydrophobization. Superhydrophobic surfaces were achieved with contact angle values as high as 157.6°, when 0.4-mm-thick coatings were modified with 0.4% LA dissolved in ethanol. The surface morphology of the superhydrophobic samples was shown to be rough at micro/nano-scale, which allowed them to demonstrate excellent anti-icing properties. Specifically, the optimized sample could delay the icing time and reduce the freezing temperature from 15 min and–4.1°C (for uncoated aluminum) to 65 min and–8.3°C, respectively, while also reducing the ice adhesion strength twice.     

镓基液态金属非润湿及不黏附玻璃表面的研究

液态金属/玻璃非润湿、不黏附研究对于镓基液态金属盛放、回收以及流动运输具有重要意义。通过气氛保护熔炼法制备GaIn_(20.5)Sn_(13)液态金属,利用不同型号砂纸打磨及旋涂镀膜处理制备不同表面形貌的玻璃片,研究合金液滴在不同玻璃表面的润湿、黏附和滚动行为。利用扫描电子显微镜(SEM)、原子力显微镜(AFM)以及接触角测量仪分别对不同玻璃的表面形貌、表面粗糙度以及润湿行为进行了测试和表征,并在其表面进行了滚动测试。结果表明:粗糙化处理和镀膜处理均可降低合金液滴在玻璃表面的润湿性,提高合金液滴的流动性。随着表面粗糙度的增大,液滴在玻璃表面的接触角不断增大,当粗糙度为187.9nm时,表面接触角达到150.6°。将表面粗糙化与镀膜处理相结合,得到镓基液态金属非润湿、不黏附的玻璃表面,接触角最高可达160.4°,同时合金液滴在其表面的滚动角为15°,滚动滞后角为3°。     

低冰粘附强度表面设计与制备研究进展

表面结冰给通讯、电力等工业领域带来巨大损失,电加热和喷洒乙二醇等主动除冰方法虽然在一定程度上可以解决上述问题,但在能源、人力、环境方面需付出较高代价。为解决这一问题,低成本、低能耗的被动式防/除冰表面被寄予厚望。防/除冰表面主要分为延长结冰时间的防冰表面和低冰粘附强度的除冰表面。由于实际工况的复杂性,除冰表面比防冰表面更具有可实现性。除冰表面主要与低表面能、界面滑动和裂纹产生相关,低冰粘附强度表面按实现机理可分为化学改性低表面能表面、润滑表面、界面滑动表面和裂纹源表面。本文对不同类型低冰粘附表面的低冰粘附强度产生的原因和表面的制备方法进行总结。同时,对冰粘附强度的测量标准进行了说明和讨论,以解释不同的测试方法对防/除冰性能测试结果造成的差异。      

Falling Angle of Fe-C-Based Alloy Droplet on Coke and Graphite

The hold-up of molten pig iron and slag melt in the coke packed bed of blast furnace (BF) causes a decrease of void between coke lumps and inhibits gas permeability. Smooth dripping of those liquids in the coke bed is desirable to keep the productivity of BF. Herein, the conditions for smooth flowing of molten iron on coke surface are calrified, and the falling angles of Fe-C and actual pig iron droplets on coke and graphite are measured at high temperature. It is found that Fe-C droplet easily slids down on coke because of small falling angle, and the falling angle of actual pig iron is even smaller, while those droplets adhere to a graphite substrate. The carbon in iron has only a small effect on the static contact angle with coke, but has a great influence on the falling angle. From the viewpoint of the roughness of coke surface, the variation of static contact angle and falling angle is discussed.     

复合管膜的润湿性及过滤污水机理

为了研究多孔复合管膜对钢铁产业污水的过滤性能及其过滤机理，采用静滴法做了水滴和油滴在复合管膜上的润湿性研究。采用扫描电镜、EDS等手段分析了使用前后的多孔复合管膜外壁及内壁的结构及成分，分析了含油污水中固体颗粒及油的过滤机理，并利用视频光学接触角测量仪测量水滴和油滴在复合管膜上接触角随时间的变化速率。结果表明，在污水过滤过程中，水中小于管膜表层微孔孔径的氧化铁等杂质进入复合管膜内部，无法随水流穿过复合管膜膜层，积累在管膜内部；随着管膜使用时间延长，氧化铁等杂质在复合管膜内部积累量增多。水在复合管膜上的润湿性良好，油滴在复合管膜上是不润湿的。     

The effect of temperature, matrix alloying and substrate coatings on wettability and shear strength of Al/Al2O3 couples

A fresh approach has been advanced to examine in the Al/Al₂O₃ system the effects of temperature, alloying of Al with Ti or Sn, and Ti and Sn coatings on the substrate, on contact angles measured using a sessile-drop test, and on interface strength measured using a modified push-off test that allows shearing of solidified droplets with less than 90 deg contact angle. In the modified test, the solidified sessile-drop samples are bisected perpendicular to the drop/Al₂O₃ interface at the midplane of the contact circle to obtain samples that permit bond strength measurement by stress application to the flat surface of the bisected couple. The test results show that interface strength is strongly influenced by the wetting properties; low contact angles correspond to high interface strength, which also exhibits a strong temperature dependence. An increase in the wettability test temperature led to an increase in the interface strength in the low-temperature range where contact angles were large and wettability was poor. The room-temperature shear tests conducted on thermally cycled sessile-drop test specimens revealed the effect of chemically formed interfacial oxides; a weakening of the thermally cycled Al/Al₂O₃ interface was caused under the following conditions: (1) slow contact heating and short contact times in the wettability test, and (2) fast contact heating and longer contact times. The addition of 6 wt pct Ti or 7 wt pct Sn to Al only marginally influenced the contact angle and interfacial shear strength. However, Al₂O₃ substrates having thin (<1 μm) Ti coatings yielded relatively low contact angles and high bond strength, which appears to be related to the dissolution of the coating in Al and formation of a favorable interface structure.     

综采割煤粉尘运移影响因素的数值模拟

为解决综采割煤粉尘质量浓度高的问题,获取粉尘控制的合理参数,改善作业环境,以邢东矿2225工作面为研究背景,依据气固两相流理论,运用Fluent软件对综采工作面割煤粉尘运动规律进行数值模拟,并与现场实测的粉尘质量浓度分布情况进行对比分析,模拟结果与实际数据基本一致.研究结果表明:工作面风速、采煤机滚筒转速、溜子速度以及壁面条件是影响综采工作面粉尘质量浓度分布的几个重要因素.当工作面平均风速在1.4m·s-1,滚筒转速不超过2.5rad·s-1,溜子速度不超过1.5m·s-1,防降尘效果最佳.同时洒水保持煤壁湿润也起到一定的捕尘作用.      

Congenital cardiopathies: anatomo-clinical, prognostic, and therapeutic features apropos of 103 cases seen at the Cardiology Clinic of the Dakar University Hospital Center

It has been demonstrated that short-term disinfection can affect the surface properties of impression materials. This study evaluated advancing contact angle, receding contact angle, inhibition and mass loss of a polyether impression materials, and two different viscosities of an addition silicone impression material after long-term immersion disinfection (18 hours). The brand names of the impression materials tested were Impregum F, Extrude Extra, and Extrude Wash, and all were tested by use of the Wilhelmy technique; first, for the nondisinfected state, which served as controls, and then after 1 and 18 hours of disinfection in a full-strength solution of acid glutaraldehyde. Weight changes before and after the disinfection process were also measured to detect weight loss and mass change over time. All materials exhibited some degree of inhibition. Polyether lost 0.4% mass in air, which indicated loss of a volatile component. Polyether and addition silicone were both relatively hydrophobic and could be disinfected with acid glutaraldehyde for up to 18 hours without affecting wettability.     

Influence of lanthanum as additive and post-treatment on the corrosion protection properties and surface morphology of mild steel chemically treated by a cerium conversion coating

The influence of cerium conversion coating (CeCC) modified by lanthanum in two forms of additive and post-treatment solution on the corrosion resistance, surface morphology and surface chemistry of the mild steel was studied. Corrosion resistance was evaluated by electrochemical impedance spectroscopy, while the scanning electron microscopy, X-ray photoelectron spectroscopy and contact angle test were employed to investigate the surface characteristics. Results reveal that the CeCC post-treated by lanthanum containing solution gives rise to the deposition of a crack free and uniform conversion coating with enhanced corrosion resistance on the steel surface. Also, the surface free energy is increased after post-treatment.