To further enhance the corrosion resistance of the porous micro-arc oxidation(MAO) ceramic layers on AZ31 magnesium alloy, superhydrophobic Mg-Al layered double hydroxide(LDH) coating was fabricated on MAO-coated AZ31...To further enhance the corrosion resistance of the porous micro-arc oxidation(MAO) ceramic layers on AZ31 magnesium alloy, superhydrophobic Mg-Al layered double hydroxide(LDH) coating was fabricated on MAO-coated AZ31 alloy by using in-situ growth method followed by surface modification with stearic acid. The characteristics of different coatings were investigated by XRD, SEM and EDS. The effect of the hydrothermal treatment time on the formation of the LDH coatings was studied. The results demonstrated that the micro-pores and cracks of MAO coating were gradually sealed via in-situ growing LDH with prolonging hydrothermal treating time. Electrochemical measurement displayed that the lowest corrosion current density, the most positive corrosion potential and the highest impedance modulus were observed for superhydrophobic LDH/MAO coating compared with those of MAO coating and LDH/MAO coating. Immersion experiment proved that the superhydrophobic LDH/MAO coating with the active anti-corrosion capability significantly enhanced the long-term corrosion protection for MAO coated alloy.展开更多
An eco-friendly superhydrophobic protective film(DTMS/TEOS silane film)was fabricated on sintered NdFeB substrate through the utilization of electrochemically assisted deposition technology.The structure,properties,an...An eco-friendly superhydrophobic protective film(DTMS/TEOS silane film)was fabricated on sintered NdFeB substrate through the utilization of electrochemically assisted deposition technology.The structure,properties,and film-forming mechanism of dodecyltrime-thoxysilane(DTMS)/tetraethoxysilane(TEOS)silane films were comprehensively analyzed using Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),potentiodynamic polarization curves and electrochemical impedance spectroscopy(EIS).Based on the test results,it can be determined that this film has a superhydrophobic property with a hydrophobicity angle of 152°.This special property can be attributed to the long alkyl chains in the DTMS molecule,the rough morphology,and the low surface energy of the DTMS/TEOS silane film.The surface of sintered NdFeB is coated with a layered three-dimensional network silane film that forms through the condensation of silanol substances.This film provides excellent corrosion resistance to the sintered NdFeB substrate,reducing its corrosion current density to 2.02×10~(-6)A/cm~2.Moreover,the impact of film on the magnetic characteristics of sintered NdFeB was assessed and found to be minimal.展开更多
Most current research on nanocomposites has focused on their bulk attributes, i.e., electrical, microwave, thermal, and mechanical properties. In practical applications, surface properties such as robustness against e...Most current research on nanocomposites has focused on their bulk attributes, i.e., electrical, microwave, thermal, and mechanical properties. In practical applications, surface properties such as robustness against environmental contamination are critical design considerations if intrinsic properties are to be maintained. The aim of this research is to combine the bulk properties of nanocomposites with the superhydrophobic surface properties provided by imprinting techniques to create a single multi-functional system with enhanced bulk properties. We report the development of a highly conductive superhydrophobic nanotube composite, which is directly superimposed with a durable dual hole pattern through imprinting techniques. The dual hole pattern avoids the use of high slenderness ratio structures resulting in a surface which is robust against physical damage. Its stable superhydrophobic properties were characterized both theoretically and experimentally. By incorporating high aspect ratio carbon nanotubes （CNTs）, the dual patterned composites can also be effectively used for anti-icing and deicing applications where their superhydrophobic surface suppresses ice formation and their quick electric heating response at low voltage eliminates remaining frost. In addition, superior electromagnetic interference （EMI） shielding effectiveness （SE） was attained, with one of the highest values ever reported in the literature.展开更多
基金Project(17JS083) supported by the Key Laboratory Program of Shaanxi Education Department,ChinaProject(2016JZ018) supported by the Key Program of Natural Science Research of Shaanxi Province,ChinaProject(51701162) supported by the National Natural Science Foundation of China
文摘To further enhance the corrosion resistance of the porous micro-arc oxidation(MAO) ceramic layers on AZ31 magnesium alloy, superhydrophobic Mg-Al layered double hydroxide(LDH) coating was fabricated on MAO-coated AZ31 alloy by using in-situ growth method followed by surface modification with stearic acid. The characteristics of different coatings were investigated by XRD, SEM and EDS. The effect of the hydrothermal treatment time on the formation of the LDH coatings was studied. The results demonstrated that the micro-pores and cracks of MAO coating were gradually sealed via in-situ growing LDH with prolonging hydrothermal treating time. Electrochemical measurement displayed that the lowest corrosion current density, the most positive corrosion potential and the highest impedance modulus were observed for superhydrophobic LDH/MAO coating compared with those of MAO coating and LDH/MAO coating. Immersion experiment proved that the superhydrophobic LDH/MAO coating with the active anti-corrosion capability significantly enhanced the long-term corrosion protection for MAO coated alloy.
基金financial support from the Public Welfare Projects of Zhejiang Province,China(No.LGG22E010002)the National Natural Science Foundation of China(Nos.52001300,52171083)。
文摘An eco-friendly superhydrophobic protective film(DTMS/TEOS silane film)was fabricated on sintered NdFeB substrate through the utilization of electrochemically assisted deposition technology.The structure,properties,and film-forming mechanism of dodecyltrime-thoxysilane(DTMS)/tetraethoxysilane(TEOS)silane films were comprehensively analyzed using Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),potentiodynamic polarization curves and electrochemical impedance spectroscopy(EIS).Based on the test results,it can be determined that this film has a superhydrophobic property with a hydrophobicity angle of 152°.This special property can be attributed to the long alkyl chains in the DTMS molecule,the rough morphology,and the low surface energy of the DTMS/TEOS silane film.The surface of sintered NdFeB is coated with a layered three-dimensional network silane film that forms through the condensation of silanol substances.This film provides excellent corrosion resistance to the sintered NdFeB substrate,reducing its corrosion current density to 2.02×10~(-6)A/cm~2.Moreover,the impact of film on the magnetic characteristics of sintered NdFeB was assessed and found to be minimal.
文摘Most current research on nanocomposites has focused on their bulk attributes, i.e., electrical, microwave, thermal, and mechanical properties. In practical applications, surface properties such as robustness against environmental contamination are critical design considerations if intrinsic properties are to be maintained. The aim of this research is to combine the bulk properties of nanocomposites with the superhydrophobic surface properties provided by imprinting techniques to create a single multi-functional system with enhanced bulk properties. We report the development of a highly conductive superhydrophobic nanotube composite, which is directly superimposed with a durable dual hole pattern through imprinting techniques. The dual hole pattern avoids the use of high slenderness ratio structures resulting in a surface which is robust against physical damage. Its stable superhydrophobic properties were characterized both theoretically and experimentally. By incorporating high aspect ratio carbon nanotubes （CNTs）, the dual patterned composites can also be effectively used for anti-icing and deicing applications where their superhydrophobic surface suppresses ice formation and their quick electric heating response at low voltage eliminates remaining frost. In addition, superior electromagnetic interference （EMI） shielding effectiveness （SE） was attained, with one of the highest values ever reported in the literature.
