耐高温防腐隔热涂料的制备与性能

耐高温防腐隔热涂料在石化管道领域具有重要的应用。文中以环氧改性有机硅树脂为基料,通过复配具有优异隔热性能的空心玻璃微珠、低温熔融玻璃粉、润湿分散剂、消泡剂等制备了一种至少耐500℃高温的防腐隔热涂料。利用扫描电子显微镜、热导分析、电化学阻抗谱,研究了不同颜基比、空心玻璃微珠含量对涂料力学性能和热学性能的影响。研究表明,颜基比为2/1,空心玻璃微珠占填料比例为40%时涂层综合性能达到最佳。     

环氧改性有机硅氧烷高温隔热涂料研究

采用环氧改性有机硅氧烷树脂为主要成膜物,以空心玻璃微珠和硅酸盐(高岭土、滑石粉、云母粉等)为主要隔热填料,制备了在常温固化的耐高温隔热涂料。采用扫描电镜对隔热涂料的微观形貌进行表征,讨论了高温下涂层的耐热与隔热机理以及高温下(600℃)涂层厚度和隔热填料对涂层隔热性能的影响。     

钛溶胶-凝胶/有机硅树脂复合膜层抗高温氧化性能的研究

探讨了将含有Mo、Cr、Si元素的钛溶胶－凝胶与有机硅树脂以不同比例混合,并在不锈钢表面涂覆成为复合膜层的制备技术。对涂层性能实验表明：钛溶胶－凝胶／有机硅树脂复合涂层较纯溶胶－凝胶涂层具有较好的热稳定性,且复合膜层在800℃的高温下具有优良的抗高温国氧化性能,而且可以避免不锈钢材料在含氯离子的溶液中发生点蚀的现象。     

透明隔热SiO2气凝胶/水性聚氨酯复合涂料的制备及性能研究

以水性聚氨酯乳液(WPU)为基体，引入SiO₂气凝胶(SA),制备了一种隔热性能优良的SA/WPU复合涂料，并探讨了SA用量对SA/WPU复合涂料性能的影响。结果表明，随着SA的加入，在保持透明度良好的条件下，复合涂料的隔热性能、附着力及硬度都得到提高。当复合涂料中SA含量为WPU基体固含量的20%时，复合涂料的隔热性能、附着力以及硬度相对最佳，可以获得综合性能优良的复合透明隔热水性聚氨酯涂料。     

基于二氧化硅气凝胶制备的多层隔热材料微观结构及热性能研究

成功制备了一种新型多层隔热材料, 其间隔层基于氧化铝纤维制备, 并由溶胶-凝胶法植入二氧化硅气凝胶颗粒。在高真空环境下(10^-3 Pa), 新型多层隔热材料当量热导率比传统材料低21.8%, 同时重量比传统材料降低了67.2%。此外, 这种新型多层隔热材料在1200 K的高温以及低真空条件下(100 Pa)也表现出良好的隔热性能。     

有机硅溶胶-凝胶防腐蚀涂层研究进展

有机硅溶胶-凝胶涂层是指以烷基烷氧基硅烷为前驱体通过溶胶-凝胶技术制备的涂层。有机硅是分子水平上的有机-无机杂化分子,因此有机硅溶胶-凝胶涂层兼具了有机材料和无机材料的性能,并且能通过合理的调控有机和无机成分来获得所需的性能。其热稳定、耐刮擦性与无机材料的结合性能明显高于普通的有机材料,柔韧性与有机材料的结合性能明显高于一般的无机涂层。近年来,这种新型的、具有特殊性能的涂层被广泛研究用来保护金属材料(如铝、铁、镁、铜基材料)。介绍了有机硅溶胶-凝胶涂层涉及的基本反应、硅烷在金属表面上的成键机理以及在不同金属上的应用等方面的研究进展,并展望了有机硅溶胶-凝胶涂层应用前景及未来的研究方向。     

304不锈钢表面纳米铝改性有机硅涂层的高温氧化和电化学行为

研究了纳米铝改性有机硅高温涂层的固化、抗650℃高温氧化性能和耐3.5% NaCl水溶液电化学腐蚀性能。当聚氨酯:有机硅的质量分数达到1:3或更高时,有机硅涂料可以在24 h内完成常温固化。制备出的纳米铝改性有机硅高温涂层表面致密,没有微观裂纹等缺陷。纳米铝改性的有机硅涂层显著提高了304不锈钢抗氧化性能,经1028 h氧化实验,基体几乎没有发生氧化,涂层没有出现开裂和剥落。纳米铝改性的有机硅涂层还显著提高了氧化后的304不锈钢耐氯化钠水溶液腐蚀性能,无涂层的304不锈钢氧化后形成的氧化膜低频阻抗仅3.2 Ω·cm²,而涂装涂层的不锈钢的低频阻抗约为1.1×10⁵ Ω·cm²。     

以烷氧基硅烷溶胶-凝胶技术制备纳米ATO透明隔热涂层

将硅氧烷水解液与纳米ATO(锑掺杂氧化锡)的乙醇浆液掺混,形成复合溶胶,然后浸涂于玻璃基底上并加热固化,以制备有机硅树脂基ATO透明隔热涂层。用SEM观察了涂层表面结构,考察了溶胶中ATO固含量对涂层透明隔热性能的影响,测试了涂层力学性能。发现:ATO以纳米颗粒形式均匀分布在玻璃表面;当溶胶中ATO固含量为10%时,涂层在可见光区透过率达80%,红外阻隔率达65%;涂层实际隔热效果明显(涂层玻璃覆盖的泡沫塑料箱内温度较无涂层玻璃覆盖箱内温度低13℃);相比早期的纳米ATO/水性聚氨酯涂层,本研究所得涂层硬度达5H,附着力达0级,耐水、耐候性能优良。研究为推动透明隔热纳米涂料的实际应用有帮助。     

TN－LG钢结构防火隔热涂料

ＴＮ－ＬＧ钢结构防火隔热涂料＊Ｎ＊Ｇ钢结构防火隔热涂料是以改性无机高温粘接剂配以膨胀经石、膨胀珍珠岩等吸热、隔热及增强材料和化学助剂合成的一种钢结构防火保护喷涂涂料。ＴＮ－ＬＧ涂料性能优良，在国内外享有很高的信誉。在北京中国国际贸易中，Ｇ３９层钢框架...     

环氧有机硅防腐蚀涂料耐热性的研究

采用环氧有机硅树脂与多种不同粒径陶瓷粉，研制出一种耐高温防腐蚀涂料。使用热重分析法、电化学交流阻抗法和电镜扫描对环氧有机硅涂料纳耐热性进行了研究。试验结果表明，耐高温防腐蚀涂料可常温固化，具有较好纳耐高温性能。涂层在钢表面达到250℃时是稳定的，具有良好的耐腐蚀效果，同时根据试验结果讨论了涂层的破坏机理。     

Structural and optical properties of AlxOy/Pt/AlxOy multilayer absorber

We report on the microstructure and optical properties of Al_xO_y–Pt–Al_xO_y interference-type multilayer films, deposited by electron beam (e-beam) deposition onto corning 1737 glass, silicon (1 1 1) and copper substrates. The structural properties were investigated by Rutherford backscattering spectrometry, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The optical properties were extracted from specular reflection/transmission, diffuse reflectance and emissometer measurements. The stratification of the coatings consists of a semi-transparent middle Pt layer sandwiched between two layers of Al_xO_y. The top and bottom Al_xO_y layers were non-stoichiometric with no crystalline phases present. The Pt layer is in the fcc crystalline phase with a broad size distribution and spheroidal shape in and between the rims of Al_xO_y. The surface roughness of the stack was found to be comparable to the inter-particle distance. The optical calculations confirm a high solar absorptance of ∼0.94 and a low thermal emittance of ∼0.06 for the multilayer stack, which is attributed not only to the optimized nature of the multilayer interference stacks, but also to the specific surface morphology and texture of the coatings. These optical characteristics validate the spectral selectivity of the Al_xO_y–Pt–Al_xO_y interference-type multilayer stack for use in high temperature solar-thermal applications.     

Optimization of AlxOy/Pt/AlxOy multilayer spectrally selective coatings for solar-thermal applications

Spectrally selective Al_xO_y/Pt/Al_xO_y multilayer absorber coatings were deposited onto corning 1737 glass, Si (111) and copper substrates using electron beam (e-beam) vacuum evaporator at room temperature. The employment of ellipsometric measurements and optical simulation was proposed as an effective method to optimize and deposit multilayer solar absorber coatings. The optical constants (n and k) measured using spectroscopic ellipsometry, showed that both Al_xO_y layers, which used in the coatings, were dielectric in nature and the Pt layer was semi-transparent. The optimized multilayer coatings exhibited high solar absorptance α ∼ 0.94 ± 0.01 and low thermal emittance ? ∼ 0.06 ± 0.01 at 82 °C. The Rutherford backscattering spectroscopy (RBS) data of Al_xO_y/Pt/Al_xO_y multilayer absorber indicated the Al_xO_y layers present in the coating were nearly stoichiometry. The scanning electron microscope analysis (SEM) result indicated that the average diameter and inter-particles distance of Pt grains were statistically about 146 ± 0.17 nm and 6-10 ± 0.2 nm respectively.     

Bulk crystalline BaPb34Bi14O3: A ceramic superconductor

The preparation conditions of the high T_C ceramic superconductor Ba(Pb,Bi)O₃ is correlated with the superconducting transition. Transition onsets of all materials are similar, but transition widths and transition completeness is strongly dependent on firing temperature. Only materials prepared over a narrow temperature range, resulting in a nearly ideal weight loss, have a complete and narrow transition.     

Interfacial microstructure of NiSix/HfO2/SiOx/Si gate stacks

Integration of NiSi_x based fully silicided metal gates with HfO₂ high-k gate dielectrics offers promise for further scaling of complementary metal-oxide- semiconductor devices. A combination of high resolution transmission electron microscopy and small probe electron energy loss spectroscopy (EELS) and energy dispersive X-ray analysis has been applied to study interfacial reactions in the undoped gate stack. NiSi was found to be polycrystalline with the grain size decreasing from top to bottom of NiSi_x film. Ni content varies near the NiSi/HfO_x interface whereby both Ni-rich and monosilicide phases were observed. Spatially non-uniform distribution of oxygen along NiSi_x/HfO₂ interface was observed by dark field Scanning Transmission Electron Microscopy and EELS. Interfacial roughness of NiSi_x/HfO_x was found higher than that of poly-Si/HfO₂, likely due to compositional non-uniformity of NiSi_x. No intermixing between Hf, Ni and Si beyond interfacial roughness was observed.     

Tc trend in high-Tc superconductors

In our previous works, we have shown that most existing ceramic superconductors can be considered to be built of superconductor-semiconductor composite and we have estimated the change in phonon spectrum of the intrinsic superconductor unit if a semiconductor unit is attached to it. Moreover, the proximity effect under the size quantization condition has been examined in the superconductor-semiconductor composite. Each of the stated effects by itself could causeT _c enhancement in general as more semiconductor blocks are added to the system. We extend our study in this paper to analyze the combined actions of phonon spectral change and proximity effect without size quantization condition onT _c variation in members of the Tl₁ series of high-T _c superconductors. Our results indicate that an optimumT _c is obtained if the stated effects are included in the idealized unit cells of the superconductors made up of a superconductor-semiconductor array.     

Electrostriction in Pb (Zn13Nb23)O3

The electrostriction in $\text{Pb (Zn}{}_{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}\text{Nb}{}_{\mathrm{<mtext>2</mtext><mtext>3</mtext>}}\text{)}\text{O}{}_3$ crystals has been investigated using a strain gauge method. In the ferroelectric phase below 140 C, the strain vs the electric field shows a hysteresis, which is ascribed to the effect of ferroelectric domains. A quadratic relation holds between the strain x and the electric polarization P as x = QP² above about 170 C in the paraelectric phase. Values of the electrostrictive Q coefficients are determined from the measurements near 190 C, as Q₁₁ = 1.6·10^?2m⁴/C², Q₁₂ = ?0.86·10^?2m⁴/C², and Q₄₄ = 0.85·10^?2m⁴/C².     

Magnetic,electrical and thermal studies on the V1−xMox02

The monoclinic-to-tetragonal structure transition of oxides V_1?xMo_x0₂ with $\text{0≤}\text{x}\text{≤0.20}$ has been studied by means of DTA, X-ray diffraction, magnetic susceptibility (powder samples) and electrical conductivity (single crystals) measurements within the temperature region 80 K to 400 K. A linear decrease of the transition temperature of 11 K per atom % Mo was observed. The magnetic susceptibility of the low temperature phase was found to be temperature independent paramagnetic for all preparations. Electrical conductivity measurements on the same phase showed crystals with $\text{x}\text{? 0.04}$ to be semiconducting, while a metallic behavior was observed in the region $\text{0.10 ?}\text{x}\text{? 0.14}$.     

n-PbTep+−Pb1−xSnxTe heterojunctions prepared by a modified hot wall technique

$\text{n-PbTe}\text{p}{}^{\mathrm{+}}\text{?}\text{Pb}{}_{\mathrm{1?x}}\text{Sn}{}_{\mathrm{x}}\text{Te}$ heterojunctions with a long wavelength spectral cutoff (λ_c ≈ 6 μm) were prepared using the double-channel hot wall technique. The electrical and photoelectrical properties of the heterojunctions at 77, 197 and 300 K were investigated. Detectors with R_oA equal to 170 Ω cm² and a quantum efficiency of 25–40% were obtained. Reasons for the shift of the long wavelength spectral cutoff of the heterojunctions towards shorter wavelengths are given.     

Anomalous Hall Effect in Sn1?x?yMnxEuyTe and Sn1?x?yMnxEryTe Mixed Crystals

The Anomalous Hall Effect (AHE) was investigated in IV–VI ferromagnetic semimagnetic semiconductors of Sn_1–x Mn _x Te codoped with either Eu or Er. The analysis of experimental data is as follows. Hall resistivity and magnetization showed that AHE coefficient R _s depends on temperature and its value decreases with thetemperature increase. We observe that above ferromagnet–paramagnet transition temperature R _s changes sign. We discuss the possible physical mechanisms responsible for observed temperature dependence of R _s , particularly change of the sign.