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111.
Shishan Xue Guanfei Liu Jingjuan Lai Peng An Yang Liu Yuanpeng Wu Yu Wang Zhiyong Ye Qiao Tang Hongwei Zhou 《大分子材料与工程》2021,306(11):2100415
Self-healing hydrogels often possess poor mechanical properties which largely limits their applications in many fields. In this work, boron nitride nanosheets are introduced into a network of the poly(vinyl alcohol)/borax (PVA/borax) hydrogels to enhance the mechanical properties of the hydrogel without compromising the self-healing abilities. The obtained hydrogels exhibit excellent mechanical properties with a tensile strength of 0.410 ± 0.007 MPa, an elongation at break of 1712%, a Young's Modulus of 0.860 ± 0.023 MPa, and a toughness of 3.860 ± 0.075 MJ m−3. In addition, the self-healing efficiency of the hydrogels is higher than 90% within 10 min at room temperature. Benefiting from the excellent self-healing properties, the shapeability of the hydrogel fragments is observed using different molds. In addition, the hydrogels display rapid pH-driven shape memory effects and can recover to their original shape within 260 s. Overall, this work provides a new approach to hydrogels with integrated excellent mechanical properties, self-healing abilities, and rapid pH-driven shape memory effects. 相似文献
112.
Zhiyong Fang Xiaohui Lai Jian Zhang Rui Zhang 《International Journal of Applied Ceramic Technology》2021,18(4):1106-1113
K2TiF6:Mn4+ is an attractive narrow-band red-emitting phosphor for warm white light-emitting diodes (LEDs). Nevertheless, the hexafluoride phosphor is liable to deliquesce in moist environments, which leads to a sharp deterioration performance of luminescence. Surface modification of K2TiF6:Mn4+ phosphor with SrF2 coating has been introduced, with the aid of KHF2 transition layer to moderate the lattice mismatch. The reaction mechanism is discussed in detail, as so as the influence of SrF2 coating on the luminescence intensity. The SrF2 coating is able to prevent the hydrolysis of internal [MnF6]2− group; thereby, the luminescence intensity retains over 90% of initial value after being immersed in distilled water for 2 h. The LED devices fabricated with commercial Y3Al5O12:Ce3+ and as-modified K2TiF6:Mn4+ phosphors exhibit bright white light with tunable chromaticity coordinate, correlated color temperature, and color rendering index. It enlightens a convenient method to enhance the moisture resistance of Mn4+ doped fluoride phosphors for commercial application in the field of white LEDs. 相似文献
113.
Eric W. Neuman Benjamin J. Lai Jeremy L. Watts Gregory E. Hilmas William G. Fahrenholtz Laura Silvestroni 《International Journal of Applied Ceramic Technology》2021,18(6):2224-2236
Densification behavior, microstructure, and mechanical properties of zirconium diboride (ZrB2) ceramics modified with a complex Zr/Si/O-based additive were studied. ZrB2 ceramics with 5–20 vol.% additions of Zr/Si/O-based additive were densified to >95% relative density at temperatures as low as 1400°C by hot-pressing. Improved densification behavior of ZrB2 was observed with increasing additive content. The most effective additive amount for densification was 20 vol.%, hot-pressed at 1400°C (∼98% relative density). Microstructural analysis revealed up to 7 vol.% of residual second phases in the final ceramics. Improved densification behavior was attributed to ductility of the silicide phase, liquid phase formation at the hot-pressing temperatures, silicon wetting of ZrB2 particles, and reactions of surface oxides. Room temperature strength ranged from 390 to 750 MPa and elastic modulus ranged from 440 to 490 GPa. Vickers hardness ranged from 15 to 16 GPa, and indentation fracture toughness was between 4.0 and 4.3 MPa·m1/2. The most effective additive amount was 7.5 vol.%, which resulted in high relative density after hot-pressing at 1600°C and the best combination of mechanical properties. 相似文献
114.
用包套拉伸法和挤压法制备Pd/Ag纤维复合材料,并通过金相和电子显微镜分别观察其微镜分别观察其微观结构,测试其性能,如电阻率,硬度,强度及接触电阻等。通过对比其工艺性及所得材料的微观结构和性能,认为挤压法优于包套拉伸法。此种Pd/Ag纤维复合材料适合Pd/Ag型复合铆钉和生产复铜铆钉。 相似文献
115.
116.
采用ST50润湿实验仪完成了钎焊并研究分析了Sn-9Zn-3Bi/Cu接头在170℃下长期时效的显微结构变化.结果表明:Sn-9Zn-3Bi/Cn接头时效至200 h后在界面处形成单一连续的Cu5Zn8化合物层;时效至500 h和1000 h后,界面处形成了3层化合物层,从铜母材侧起,分别为Cu-Sn化合物层,Cu-Zn化合物层和Sn-Cu化合物层;随着时效时间的增加,整个金属化合物层变厚,而Cu-Zn化合物层减薄,表明Cu-Zn化合物层在时效过程中具有不稳定性. 相似文献
117.
Highly conductive transparent aluminium-doped ZnO (ZnO:A1) films were successfully deposited by CW-CO2 laser-induced evaporation. Optimisation of evaporation parameters was based on laser power, substrate temperature, O2 partial pressure in the vacuum chamber and amount of Al in the ZnO source pellet. ZnO:A1 films with an electrical resistivity as low as 6.6 × 10−2Ω·cm and an optical transmission of 80% at 500nm were obtained at laser power of 15 W, substrate temperature of about 200°C, O2 partial pressure of 6—7 × 10−4 Torr and 5wt.% Al. Conductivity of ZnO films can be increased one order via Al-doping in ZnO films. The films obtained by laser-induced evaporation have compared quite favorably with the high quality films obtained by sputtering. 相似文献
118.
基于多元素靶溅射的Andersen-Sigmund关系式,在分析了大量的二、三元素合金溅射稳定态靶表面化学成分的变化之后,发现各元素之间表面结合能之比几乎与靶体化学成分无关。只要给各元素之间设定适当的表面结合能比,就可以很容易地计算出三元合金靶稳定态表面化学成分,至少对于用2keV氩离子轰击的Ag-Pd-Au三元合金靶系来说,其计算结果都与实验值一致。所分析的实验数据是在常温下取得的,所以可不考虑离子轰击诱发的Gibbs偏析,其结论很可能是多元合金靶溅射的一般规律。此外,由Gaidikas等最近所提出的所谓择优溅射中的“基体效应”理论是无实验依据的。 相似文献
120.
在自制弯曲疲劳装置上 ,对 3种高强对位芳纶及超高相对分子质量聚乙烯纤维 (Dyneema SK65 )进行双面弯曲疲劳试验。结果表明 ,Twaron 2 0 0 0弯曲疲劳寿命的自然对数与预加应力、弯曲角度呈线性关系 ,Dyneema SK65弯曲疲劳寿命明显长于对位芳纶 ,Twaron 2 0 0 0 ,Kevlar 12 9相近 ,都比Kevlar 2 9略长 ;高强型对位芳纶的弯曲疲劳断裂断口芯层呈现出“毛笔头”或“拔丝形”原纤化分裂形态 ,超高相对分子质量聚乙烯纤维弯曲疲劳断裂断口有明显的脆性折断形态 ,无原纤出现。 相似文献