钕铁硼(NdFeB)永磁材料凭借其优异的磁性能在电子、汽车、能源等领域获得了广泛应用。然而,该材料存在一个显著缺陷,即易受环境因素影响而发生腐蚀,这限制了其使用的长期稳定性。为了有效提升NdFeB磁体的耐腐蚀性能,科研人员开发了多种...钕铁硼(NdFeB)永磁材料凭借其优异的磁性能在电子、汽车、能源等领域获得了广泛应用。然而,该材料存在一个显著缺陷,即易受环境因素影响而发生腐蚀,这限制了其使用的长期稳定性。为了有效提升NdFeB磁体的耐腐蚀性能,科研人员开发了多种涂层体系,如金属镀层、陶瓷涂层和有机涂层等。本文针对烧结NdFeB磁体,采用刷涂法制备Zn层、Al层、ZnAl复合涂层,进一步地在ZnAl涂层体系中引入纳米氧化锌(ZnO)颗粒进行改性处理。重点关注了各类涂层的微观组织形貌,深入探讨其抗腐蚀性能、稳定性及磁性能方面的作用机制。此外,本文通过电化学测试、中性盐雾试验等手段,系统评估了上述涂层的防护效果。研究结果表明,ZnO-ZnAl复合涂层在提高磁体耐腐蚀性方面具有优异表现,能够有效延长NdFeB磁体的使用寿命。NdFeB permanent magnets have been widely used in electronics, automotive, and energy industries due to their excellent magnetic properties. However, a significant drawback of NdFeB magnets is that they are easily affected by environmental factors. Which limits the long-term stability in use. In order to effectively improve the corrosion resistance of NdFeB magnets, various coating systems have been developed, such as metallic coatings, ceramic coatings, and organic coatings. In this paper, Zn coating, Al coating and ZnAl composite coating are prepared by brush coating on sintered NdFeB magnets. Furthermore, Nano-ZnO particles are further introduced into the ZnAl coating system for modification. We focused on the microstructure morphology of various coatings, and deeply explored the mechanism in terms of corrosion resistance, stability, and magnetic properties. Furthermore, electrochemical tests and neutral salt spray (NSS) tests were conducted to systematically evaluate the protective performance of the coatings. The results demonstrated that the ZnO-ZnAl composite coating exhibited superior corrosion resistance, significantly extending the service life of NdFeB magnets.展开更多
A poly(methyl acrylate)(PMA)/ZnAl layered double hydroxide(ZnAl-LDH) intercalation nanocomposite is synthesized by in situ polymerization of methyl acrylate with ogano-modified ZnAl-LDH(O-ZnAl-LDH). Its structure and ...A poly(methyl acrylate)(PMA)/ZnAl layered double hydroxide(ZnAl-LDH) intercalation nanocomposite is synthesized by in situ polymerization of methyl acrylate with ogano-modified ZnAl-LDH(O-ZnAl-LDH). Its structure and morphology are confirmed by X-ray diffraction(XRD) and transmission electron microscopy(TEM) image. The d 001 of O-ZnAl-LDH is expanded to 2.85 nm after polymerization from 2.63 nm, which indicates the intercalation of PMA chains into the galleries of O-ZnAl-LDH. The (001) diffraction of PMA/ZnAl-LDH nanocomposite is broad due to the exfoliation of some O-ZnAl-LDH layers. The TEM image shows that the most of the layers of O-ZnAl-LDH are stacked with a distance of about 3 nm while some of them are exfoliated and dispersed disorderly in the PMA matrix.展开更多
ZnO/Znml2O4 nanocomposites with heteronanostructures were successfully prepared by co-precipitation method. The as-prepared samples were characterized by HRTEM, TEM, XRD, BET, TG-DTA, and UV-Vis spectra techniques. Th...ZnO/Znml2O4 nanocomposites with heteronanostructures were successfully prepared by co-precipitation method. The as-prepared samples were characterized by HRTEM, TEM, XRD, BET, TG-DTA, and UV-Vis spectra techniques. The photoeatalytic activities of the as-prepared samples were evaluated by the photocatalytic degradation of methyl orange and inactivation of Escherichia coli in suspension under the irradiation of the simulated sunlight. The effects of compositions, calcination temperatures, concentration ofphotocatalysts and light source on the photocatalytic activities were systematically studied. The results show that when the concentration of ZnO/ZnA1204 photocatalyst with the starting Zn to Al molar ratio of 1：1.5 calcined at 600 ℃ is 1.0 g/L, the maximum photocatalytic degradation rate of 98.5% can be obtained in 50 min under the irradiation of the simulated sunlight. Under the same conditions, an inactivation rate of 99.8% for E.coli is achieved in 60 min.展开更多
文摘钕铁硼(NdFeB)永磁材料凭借其优异的磁性能在电子、汽车、能源等领域获得了广泛应用。然而,该材料存在一个显著缺陷,即易受环境因素影响而发生腐蚀,这限制了其使用的长期稳定性。为了有效提升NdFeB磁体的耐腐蚀性能,科研人员开发了多种涂层体系,如金属镀层、陶瓷涂层和有机涂层等。本文针对烧结NdFeB磁体,采用刷涂法制备Zn层、Al层、ZnAl复合涂层,进一步地在ZnAl涂层体系中引入纳米氧化锌(ZnO)颗粒进行改性处理。重点关注了各类涂层的微观组织形貌,深入探讨其抗腐蚀性能、稳定性及磁性能方面的作用机制。此外,本文通过电化学测试、中性盐雾试验等手段,系统评估了上述涂层的防护效果。研究结果表明,ZnO-ZnAl复合涂层在提高磁体耐腐蚀性方面具有优异表现,能够有效延长NdFeB磁体的使用寿命。NdFeB permanent magnets have been widely used in electronics, automotive, and energy industries due to their excellent magnetic properties. However, a significant drawback of NdFeB magnets is that they are easily affected by environmental factors. Which limits the long-term stability in use. In order to effectively improve the corrosion resistance of NdFeB magnets, various coating systems have been developed, such as metallic coatings, ceramic coatings, and organic coatings. In this paper, Zn coating, Al coating and ZnAl composite coating are prepared by brush coating on sintered NdFeB magnets. Furthermore, Nano-ZnO particles are further introduced into the ZnAl coating system for modification. We focused on the microstructure morphology of various coatings, and deeply explored the mechanism in terms of corrosion resistance, stability, and magnetic properties. Furthermore, electrochemical tests and neutral salt spray (NSS) tests were conducted to systematically evaluate the protective performance of the coatings. The results demonstrated that the ZnO-ZnAl composite coating exhibited superior corrosion resistance, significantly extending the service life of NdFeB magnets.
文摘A poly(methyl acrylate)(PMA)/ZnAl layered double hydroxide(ZnAl-LDH) intercalation nanocomposite is synthesized by in situ polymerization of methyl acrylate with ogano-modified ZnAl-LDH(O-ZnAl-LDH). Its structure and morphology are confirmed by X-ray diffraction(XRD) and transmission electron microscopy(TEM) image. The d 001 of O-ZnAl-LDH is expanded to 2.85 nm after polymerization from 2.63 nm, which indicates the intercalation of PMA chains into the galleries of O-ZnAl-LDH. The (001) diffraction of PMA/ZnAl-LDH nanocomposite is broad due to the exfoliation of some O-ZnAl-LDH layers. The TEM image shows that the most of the layers of O-ZnAl-LDH are stacked with a distance of about 3 nm while some of them are exfoliated and dispersed disorderly in the PMA matrix.
基金Project(21271071)supported by the National Natural Science Foundation of ChinaProject(21306041)supported by the National Natural Science Young Foundation of China
文摘ZnO/Znml2O4 nanocomposites with heteronanostructures were successfully prepared by co-precipitation method. The as-prepared samples were characterized by HRTEM, TEM, XRD, BET, TG-DTA, and UV-Vis spectra techniques. The photoeatalytic activities of the as-prepared samples were evaluated by the photocatalytic degradation of methyl orange and inactivation of Escherichia coli in suspension under the irradiation of the simulated sunlight. The effects of compositions, calcination temperatures, concentration ofphotocatalysts and light source on the photocatalytic activities were systematically studied. The results show that when the concentration of ZnO/ZnA1204 photocatalyst with the starting Zn to Al molar ratio of 1：1.5 calcined at 600 ℃ is 1.0 g/L, the maximum photocatalytic degradation rate of 98.5% can be obtained in 50 min under the irradiation of the simulated sunlight. Under the same conditions, an inactivation rate of 99.8% for E.coli is achieved in 60 min.
