45#钢表面Ni-W/ZnO超疏水复合涂层的制备及性能研究

采用电沉积工艺并结合喷涂法在45#钢表面制备Ni-W/ZnO超疏水复合涂层,表征了复合涂层的微观形貌和主要成分,并对复合涂层的疏水性、机械稳定性及耐蚀性进行测试分析。结果表明：复合涂层表面形成微纳米分级结构,主要成分为Ni、W、Zn、O、C和Si元素,改性ZnO颗粒在复合涂层中呈较均匀分散状态。复合涂层表面水滴接触角达到151.4°,表现出超疏水性能,并且经20次胶带提拉、20次砂粒冲击和20个周期砂纸摩擦后接触角仍然大于150°,能稳定地保持超疏水性能而且具有良好的机械稳定性。复合涂层还表现出优异的耐蚀性,其腐蚀电流密度仅为6.79×10^-7 A/cm²,极化电阻达到3.25×10⁴Ω·cm²,相比于常规Ni-W合金镀层,能为45#钢提供理想的腐蚀防护作用。     

低表面能环氧树脂超疏水涂层的制备与研究

制备工艺复杂、表面粗糙结构耐久性差等因素制约了超疏水涂层在现实中的大规模应用。本研究采用十八烷酸对环己二胺四官能团环氧树脂(AG602)接枝改性制备了低表面能环氧树脂SAEP,并将SAEP与疏水纳米二氧化硅粒子共混后涂膜,对其热固化后涂层的性能进行研究。结果表明：当nmSiO₂质量分数为30%时,涂层表面具备超疏水性,水接触角为156.5°,滚动角为5.1°。涂层在承受砂纸45次循环打磨后仍能保持超疏水性。此外,涂层还具备优良的自清洁能力与耐酸碱腐蚀能力。     

环氧/聚二甲基硅氧烷/MCM-41超疏水涂层的制备与性能研究

针对常规超疏水涂层制备工艺繁琐等问题，以介孔SiO₂纳米颗粒(MCM-41)为填料和载体，聚二甲基硅氧烷(PDMS)为低表面能改性剂，环氧树脂及其固化剂为成膜物，采用喷涂法制备了超疏水涂层。通过场发射扫描电子显微镜、共聚焦显微镜、接触角测量仪、拉伸试验机对其表面形貌、结构、疏水性及附着力进行表征。重点考察了PDMS改性的MCM-41(MCM-41/PDMS)和树脂基体质量比对涂层性能的影响。结果表明：当MCM-41/PDMS质量分数为55%，可以得到涂层疏水性(接触角150°，滚动角9°)和附着力(7.33 MPa)的最佳匹配，涂层经过胶带剥离300次和磨损150周期后，水接触角仍大于150°。     

二氧化硅纳米颗粒/硅树脂复合超疏水功能涂层的制备和性能研究

将二氧化硅纳米颗粒和硅树脂制成混合液,采用喷涂法(spray-coating)制备出了具备超疏水性的复合涂层.研究了二氧化硅、硅树脂不同含量配比对涂层疏水性能的影响,结果表明复合涂层的接触角随二氧化硅含量的增加而增加.在二氧化硅含量大于3%(质量分数)时,涂层显现超疏水性;当二氧化硅含量为3%(质量分数)、硅树脂含量为7%(质量分数)时,涂层与水的接触角达到151.6°,滚动角接近0°.通过扫描电子显微镜(SEM)观察涂层表面的微观结构,发现超疏水性的涂层具备微-纳复合阶层结构,类球状突起粒径在5μm左右,类球状突起上分布纳米团聚颗粒,直径约为50 nm.这种类似荷叶表面的微(纳复合阶层结构,结合硅树脂的低表面能,使得复合涂层具备了超疏水性能.     

透明超疏水SiO2/硅酮胶复合涂层的制备及性能

以疏水纳米SiO_2和中性硅酮结构胶为主要原料,采用喷涂法在玻璃表面制备出透明超疏水SiO_2/硅酮胶复合涂层。采用FTIR、SEM、接触角测量仪和紫外-可见分光光度计对复合涂层的分子结构、微观形貌、润湿性和透光率进行表征。讨论了纳米SiO_2的添加量与涂层表面微结构、水接触角、透明性三者的关系,考察了复合涂层的耐水冲击性能和耐水稳定性能。结果表明:SiO_2/硅酮胶复合涂层表面呈连续的多孔网络状,团聚的SiO_2纳米粒子分散在作为骨架的亚微米级硅酮胶周围,构成了微纳米双尺度的复合粗糙结构。当SiO_2质量分数为2.0%时,复合涂层的水接触角达到最大为169.8°±0.7°,在380～760nm可见光范围内的平均透光率为82.9%;当硅酮胶质量分数为4%时,复合涂层分别经5 h水冲击以及10 d水浸泡后,水接触角仍保持在140°以上。     

金属表面PDA/PTFE超疏水涂层抑垢与耐腐蚀性能

超疏水涂层具有极广的应用前景，然而在金属表面制备稳定的超疏水涂层具有一定挑战。为提高涂层稳定性，本文通过简单浸泡法在不锈钢表面形成稳定的聚多巴胺（PDA）中间涂层，随后采用电泳沉积法在PDA修饰后的表面制备聚四氟乙烯（PTFE）超疏水涂层。测试中采用场发射扫描电镜、接触角测试仪及电化学测试仪进行PDA/PTFE涂层分析和表征。制备的PDA/PTFE涂层表面呈现凸起结构，提高电沉积制备时间与溶液中水含量，涂层表面水接触角呈现先增加后降低的变化趋势，制备涂层中最大水接触角为160.2°±1.3°，相应涂层的表面能为5.57mN/m。胶带剥离与砂纸磨损试验表明，PDA/PTFE涂层具有较好的稳定性。污垢沉积试验表明，浸泡在50℃、70℃与90℃碳酸钙过饱和溶液12h后，与不锈钢相比，涂层抑垢率分别为64.71%、72.22%与81.25%。电化学测试表明，PDA/PTFE超疏水涂层具有较好的耐腐蚀性能，与不锈钢相比，涂层缓蚀率为95.1%。     

钛合金表面超疏水膜的制备及其耐蚀性与机械稳定性

采用阳极氧化工艺在Ti6A14V钛合金表面制备阳极氧化膜作为过渡层,然后喷涂Si O₂颗粒溶胶烘烤使其固化成膜,再通过正辛基三乙氧基硅烷表面修饰,制备出具有微纳米表面结构、接触角为151.6°的超疏水膜。结果表明：超疏水膜的主要成分为Ti、O、Si和C元素,腐蚀电流密度仅为8.06×10^-8 A/cm²,较裸钛合金降低约一个数量级,并且电荷转移电阻和低频阻抗模值较裸钛合金分别增大约7000Ω·cm²、3000Ω·cm²,表现出良好的耐蚀性,可作为耐腐蚀膜层对钛合金起到防护作用。超疏水膜经受80次落砂冲击、50次胶带剥离以及沿砂纸往复摩擦400 cm后,接触角仍然大于150°,保持超疏水状态。蜂窝状多孔结构的阳极氧化膜充当过渡层,使溶胶膜和表面修饰形成的薄膜与钛合金基体牢固结合,从而表现出良好的机械稳定性。     

超疏水近红外吸收涂层的制备及性能表征

以纳米Si O2为微纳结构改性剂、聚二甲基硅氧烷(PDMS)为粘合剂、Sm2O3为功能颜料,通过合理的涂层结构设计,采用刮涂法制备得到具有超疏水特性的PDMS/Sm2O3复合涂层。分析探讨了PDMS和Sm2O3配比(质量比)、纳米Si O2添加量及表面微纳结构层对涂层性能的影响规律。结果表明,PDMS和Sm2O3质量比对涂层性能具有重要影响,当m(PDMS)∶m(Sm2O3)=6∶4时,涂层对1.06μm近红外光的反射率可低至58.8%,涂层的水接触角可达到113°,明显高于传统聚氨酯基近红外吸收涂层的水接触角。通过在PDMS/Sm2O3复合涂层表面涂覆具有明显乳突状结构特征的PDMS/SiO2微纳结构层,可使涂层实现超疏水特性。PDMS/Sm2O3复合涂层表面经Si O2质量分数为30%的PDMS/SiO2微纳结构层涂覆后,其水接触角可增大到158°,滚动角可低至4°,同时具有较低的1.06μm近红外反射率(61.4%)性能。     

基于静电粉末喷涂EP-ETFE-SiO_2复合涂层的制备与耐腐蚀性能研究

制备环氧树脂-乙烯-四氟乙烯共聚物(EP-ETFE)颗粒及EP-ETFE-SiO2超疏水复合涂层。使用接触角测量仪、Taber耐磨试验仪、电化学工作站以及耐老化试验箱对涂层的摩擦性能、腐蚀性能以及老化性能等进行测试。结果表明:ETFE与EP的质量比为2∶1,疏水性气相SiO2颗粒含量在3%时,EP-ETFE-SiO2复合涂层可获得良好的综合性能,涂层在500次Taber耐磨试验后仍能维持(152.5±1.8)°的接触角与(3.8±0.6)°的滚动角。相比纯铝基材,涂有EP-ETFE-SiO2复合涂层的表面腐蚀电流可从10-3mA/cm2降低到10-6mA/cm2,腐蚀电位从-955 mV升高至-362 mV,同时阻抗谱图与循环伏安曲线展现出优异的耐腐蚀性能。EP-ETFE-SiO2复合涂层经历200 d老化实验后的水接触角,仍能维持(153.1±0.8)°的接触角与(2.7±0.5)°的滚动角,同时展现出优异的耐老化性能。     

镁合金表面Ni-P/Cu-Zn超疏水复合涂层制备及耐蚀性研究

本文主要研究了镁合金表面Ni-P/Cu-Zn超疏水复合涂层的制备和耐蚀性.复合涂层通过化学镀镍磷、电镀铜锌合金、阳极氧化、表面修饰后获得,化学镀Ni-P层为内层,电镀Cu-Zn层为中间层,超疏水层为外层.对复合涂层的结构和性能进行了表征.实验结果表明,复合涂层与基底结合力强,无鼓泡脱落现象,涂层厚度约为34μm.Ni-P/Cu-Zn涂层氧化后表面形成微纳米结构,用十八烷基硫醇修饰后的涂层具有优良的超疏水性,水的表面接触角约为155°,涂层的自腐蚀电流密度相对于未修饰涂层和基底下降1～2个数量级,阻抗大幅提升,说明涂层具有很好的耐蚀性,能够为镁合金提供较好的保护.     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Wet Milling of Fe/Al/Al2O3 and Fe2O3/Al/Al2O3 Powder Mixtures

Wet milling of Al₂O₃-aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al₂O₃ and Fe₂O₃/Al/Al₂O₃ powder mixtures. The influence of the milling process on the physical and chemical properties of the milled powders has been studied. Particle refinement and homogenization were found not to play a dominant role, whereas plastic deformation of the metal particles leads to the formation of dislocations and a highly disarranged polycrystalline structure. Although no chemical reactions among the powder components in Fe₂O₃/Al/Al₂O₃ powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al₂O₃ powder mixtures caused by mechanical alloying was detected. Chemical reactions of Fe and Al particle surfaces with the atmosphere and the milling media lead to the formation of highly porous hydroxides on the particle surfaces. Hence the specific surface area of the powders increases, while the powder density decreases during milling. The fraction of Fe oxidized during milling was determined to be 0.13. The fraction of Al oxidized during milling strongly depends on the metal content of the powder mixture. It ranges between 0.4 and 0.8.     

Participation of lewis base on vinyl chloride polymerization with Al(C2H5)3CCl4 catalyst system

The polymerization of vinyl chloride has been investigated using an $\text{Al}\text{(}\text{C}{}_2\text{H}{}_5\text{)}{}_3\text{CCl}{}_4$ catalyst system in the presence of various Lewis bases. Effective Lewis bases are γ-butyrolactone, diglyme and diethylenetriamine which are multidentate. The rate of polymerization is dependent not only on the basicity of the Lewis base used but also on a coordination number of one. The latter is the predominant factor. For the effect of polymeric amines, a tentative hypothesis is discussed.     

Sintering of Si3N4-Y2O3-Al2O3

Sintering kinetics of the system Si₃N4-Y2O₃-Al₂O3 were determined from measurements of the linear shrinkage of pressed disks sintered isothermally at 1500° to 1700°C. Amorphous and crystalline Si₃N₄ were studied with additions of 4 to 17 wt% Y₂O₃ and 4 wt% A1₂O₃. Sintering occurs by a liquid-phase mechanism in which the kinetics exhibit the three stages predicted by Kingery's model. However, the rates during the second stage of the process are higher for all compositions than predicted by the model. X-ray data show the presence of several transient phases which, with sufficient heating, disappear leaving mixtures of β ' -Si₃N₄ and glass or β '-Si₃N₄, α '-Si₃N₄, and glass. The compositions and amounts of the residual glassy phases are estimated.     

Synthesis and Characterization of Ti0.33Ta0.33Nb0.33C and Ti0.33Ta0.33Nb0.33CxN1-x Whiskers

Ta_0.33Ti_0.33Nb_0.33C and Ta_0.33Ti_0.33Nb_0.33C _x N_{1− x} whiskers were synthesized via a carbothermal vapor-liquid-solid growth mechanism in the temperature range 900°-1450°C in Ar or N₂. The optimum temperature was 1250°C. Whiskers were obtained in a yield of 70-90 vol%. The whiskers were 0.5–1 µm in diameter and 10–30 µm in length. The starting materials that produced the highest whisker yield were: TiO₂, Ta₂O₅, Nb₂O₅, C, Ni, and NaCl. C was added to reduce the oxides, and Ni to catalyze whisker growth. NaCl was used as a source of Cl for vapor-phase transportation of Ta and Nb oxochlorides and Ti chlorides to the catalyst. The catalyst metal was recycled several times during the synthesis and was transported as NiCl₂( g ) according to thermodynamic calculations. The rate of formation and the chemical composition of the whiskers depended on the synthesis temperature, the choice of catalyst, and the atmosphere. At low temperatures, the whiskers were enriched in Nb and Ta, whereas the Ti content increased with increased synthesis temperature.