Evolution mechanism of the microstructure and mechanical properties of plasma-sprayed yttria-stabilized hafnia thermal barrier coating at 1400 °C

Yttria stabilized hafnia (Hf_0.84Y_0.16O_1.92, YSH16) coatings were sprayed by atmospheric plasma spraying (APS). The effects of thermal aging at 1400 °C on the microstructures, mechanical properties and thermal conductivity of the coatings were studied. The results show that the as-sprayed coating was composed of the cubic phase, and the nano-sized monoclinic (M) phase was precipitated in the annealed coating. The presence of M phase effectively constrained the sintering of the coating due to its superior sintering-resistance. The Young's modulus kept at a nearly same level of ~78 GPa even after annealing, and the coating annealed for 6 h yielded a maximum value of hardness but revealed a declining tendency in the Vicker's hardness with prolonged sintering time. The thermal conductivity increased from 0.8-0.95 W m^-1 K^-1 at as-sprayed state to 1.6 W m^-1 K^-1 after annealing at 1400 °C for 96 h. The dual-phase coating is promising to serve at temperatures above 1400 °C due to its excellent thermal stability and mechanical properties.     

Reliability study of TaON capacitors: From leakage current characterization to ESD robustness prediction

Electrostatic discharges are a permanent threaten for integrated metal–insulator–metal capacitors. Hence, the development of comprehensive models able to predict the capacitors robustness against ESD aggression is of major importance to adopt the adequate protection strategies. This work focuses more particularly on the failure mechanisms of TaON capacitors submitted to HBM ESD waves. From leakage current characterization to thermal dissipation effects, we propose a complete reliability model which accurately foresees not only ESD failure voltage, but also TDDB capacitors lifetime.     

Facile fabrication of superhydrophobic polysiloxane/magnetite nanocomposite coatings with electromagnetic shielding property

Superhydrophobic coatings, with a water contact angle (WCA) of 158.3° and a sliding angle of 4.3°, were readily prepared by mixing silicone resin, aminopropyltriethoxysilane and Fe₃O₄ nanoparticles, and subsequently curing at an ambient temperature. The surface wettability, surface morphology and composition, and long-term durability of the coatings were investigated by WCA analysis, field emission scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and QUV accelerated weathering tests, respectively. The results show that the coatings display a pencil hardness of B, excellent weatherability, and electromagnetic shielding effectiveness beyond 60% in the frequency range of 10–3000 MHz.     

Novel surfactant-free waterborne acrylic-silicone modified alkyd hybrid resin coatings containing nano-silica for the corrosion protection of carbon steel

We report a novel waterborne acrylic-silicone modified alkyd nanocomposite latex containing nano-silica prepared by the surfactant-free miniemulsion polymerization. The influences of γ-methacryloxy-propyltrimethoxysilane- (MPS-) modified nano-silica particle contents to the thermal, mechanical and anti-corrosion performance of hybrid latex coatings were studied. The results revealed that the incorporation of nano-silica particles into latex films could directly increase the thermal stability and mechanical properties. Electrochemical corrosion studies revealed that these nanocomposite coatings exhibited superior corrosion resistance performance (inhibition efficiency 99.36% and corrosion rate 1.09 × 10 ^?3 mm per year) than that of the control system (without SiO₂ NPs).     

生物基金属保护剂TPA对碳钢包装材料防腐性能影响

目的 采用生物基材料,制备金属保护剂对碳钢包装材料进行防腐保护,解决传统金属表面处理方式污染环境和危害人体健康的弊病,获得性能优良的生物基金属保护剂。方法 以植物萃取成分提炼单宁酸、植酸与水共混复配,制备生物基金属保护剂TPA,并对碳钢表面进行涂覆处理,获得钝化膜。通过红外光谱(FTIR)、光学显微镜(OM)、盐雾测试(HSS)、电化学阻抗分析(EIS)等分析手段,考察不同种类、不同复配比例、不同浓度生物基保护剂对金属防腐性能的影响。结果 不同生物酚羟基酸如单宁酸、植酸、没食子酸、酒石酸均对碳钢具有防腐保护功能,其中植酸、单宁酸防腐性能较好。采用植酸与单宁酸共混反应得到的生物基金属保护剂TPA具有最佳的防腐性能。当TPA中植酸与单宁酸的质量比为2∶1、TPA质量分数为3%时,TPA保护剂处理后的钝化膜电化学阻抗模值可达5.02´10⁷Ω∙cm²,远高于单一生物酚羟基酸保护剂的阻抗模值(<10⁴Ω∙cm²)。结论 生物基金属保护剂TPA中的单宁酸与植酸通过氢键作用,形成分子缔合复合保护剂。TPA保护剂能与铁离子作用,形成致密钝化膜,克服了单宁酸钝化膜的应力开裂、植酸钝化膜孔隙疏松等缺陷,显著提升了TPA钝化膜的防腐性能。生物基金属保护剂TPA可用于碳钢类包装材料的防腐保护。     

改性聚酯涂层的制备及在食品包装材料中的应用

目的 制备改性聚酯涂层,解决纯聚酯涂层与基材润湿性较差,导致涂层出现附着力差、缩孔等问题,获得综合性能优异的镀锡板食品包装用新型涂层材料。方法 以二元酸、二元醇为原料,通过缩合聚合方法合成聚酯树脂,用双酚F型环氧树脂化学改性聚酯树脂,制备环氧改性聚酯树脂,并用氨基硅烷作为固化剂构筑硅烷化环氧改性聚酯涂层。通过GPC、FTIR、TGA、OM、WCA、附着力等分析、考察硅烷化环氧改性聚酯树脂涂层与常规氨基树脂固化环氧改性聚酯涂层的性能差异。结果 通过性能对比发现,树脂与硅烷固化剂质量比为3∶1时,mEster 1.0和mEster 1.1涂层样品综合性能最佳,涂层在镀锡板基材表面润湿性好,缩孔等缺陷少,耐水煮性好,铅笔硬度为2H,丙酮擦拭50次后表面仍完好,分解温度在250℃以上。结论 硅烷化环氧改性聚酯树脂涂层中低表面自由能的Si-O-Si键对其性能提升有关键作用,该涂层可应用于镀锡板等金属基材食品包装保护材料。     

Extended hydrophobicity and self-cleaning performance of waterborne PDMS/TiO<Subscript>2</Subscript> nanocomposite coatings under accelerated laboratory and outdoor exposure testing

It has been shown that incorporation of TiO₂ nanoparticles into hydrophobic coatings can show self-cleaning performance. Accelerated laboratory testing indicated that the coats retain their hydrophobic nature for an extended time period. In this paper, hydrophobic polydimethylsiloxane (PDMS)/TiO₂ nanocomposite coatings with a TiO₂ content of 0–40% were fabricated by simple blending of a PDMS dispersion with an aqueous TiO₂ nanoparticle dispersion. Their long-term hydrophobicity and self-cleaning performance were investigated both in laboratory and real-world outdoor testing. As expected, TiO₂ nanoparticle-based coatings exhibited better self-cleaning relative to the TiO₂-free PDMS control coating as measured by methylene blue degradation testing. Excellent long-term hydrophobicity was observed in accelerated weathering testing when they contained the appropriate levels of TiO₂ nanoparticles (i.e., 0–30%). However, the same PDMS/TiO₂ coatings did not show self-cleaning performance, and instead, exhibited improved dirt pickup resistance, in outdoor exposure testing. Sustained hydrophobicity was observed in outdoor exposure testing for the clear films except when TiO₂ levels were at 40%. The hysteresis of water contact angle (HWCA) significantly increased for the PDMS control coating, and water beading was lost as the film surface picked up dirt. In contrast, the TiO₂-based coatings with appropriate TiO₂ levels maintained a relatively low HWCA after outdoor exposure and no water sheeting on rainy days was observed. This result demonstrates that while photocatalytic TiO₂ nanoparticles can maintain coating hydrophobicity upon outdoor exposure, long-term self-cleaning performance in polluted environments has not yet been achieved with this type of coating under real-world conditions.     

Effects of TiO2 doping on the defect chemistry and thermo-physical properties of Yb2O3 stabilized ZrO2

Yb₂O₃ stabilized ZrO₂ (YbSZ) doped with different TiO₂ contents were produced, and their phase structure, thermal conductivities and thermal expansion coefficients were investigated. A new solid-solution model is proposed, i.e. Ti⁴⁺ would take the interstitial sites when its content is below a critical value (≤2.5 mol%) and then substitute for Zr⁴⁺. The abnormal lattice volume and thermo-physical properties of 2.5 mol% TiO₂ doped YbSZ, and the positive effects of TiO₂ doping on the thermal conductivity at moderate doping level are consistent with the new defect model. However, monoclinic phase is formed when the TiO₂ content reaches to 10 mol% and its content increases with doping content, which have negative influence on the thermo-physical properties. Considering the comprehensive properties, 10 mol% TiO₂ doped YbSZ is considered as a promising thermal barrier coating ceramic.     

Review:Fabrication and Application of Zwitterion-based Functional Coatings

综述：两性离子基功能涂层制备与应用

谭锦炎^1,2, 周树学¹, A. Catarina C. Esteves^2,3, 武利民¹

（1. 复旦大学 材料科学系，聚合物分子工程国家重点实验室，教育部先进涂料工程研究中心，上海 200433 ；2. 埃因霍芬理工大学 化学与化工系物理化学实验室，埃因霍芬 5600，荷兰; 3. 埃因霍芬理工大学 复杂分子系统研究所，埃因霍芬 5600，荷兰）

中文说明：

由于两性离子基材料具有特殊的物理和化学特性，其在功能涂层制备中的应用引起了广泛的研究兴趣。两性离子分子结构中同时含有正负电荷，可以通过静电作用形成水合层，从而抵抗油污、蛋白质、微生物的粘附，抑制生物膜的生成。本文一方面阐述了两性离子的作用机制，另一方面从制备策略出发，详细介绍了两性离子基粘合剂、两性离子基添加剂、两性离子前驱体后处理等3种两性离子基功能涂层的制备路线进展。另外，讨论了两性离子基功能涂层的应用领域，包括医疗植入物涂层、海洋防污涂层、防油涂层等，阐述了两性离子基涂层在特定应用场合下的作用机制。最后，本文对两性离子基功能涂层的未来发展进行了展望，并提出了一些建议。

关键词：两性离子材料；功能涂层；医疗植入物涂层；海洋防污涂层；防油涂层；两亲涂层；可降解涂层