Enhancement of Active Anticorrosion via Ce-doped Zn-Al Layered Double Hydroxides Embedded in Sol-Gel Coatings on Aluminum Alloy

Ce-doped Zn-Al layered double hydroxide（LDH） nanocontainer was synthesized by a co-precipitation method. X-ray diffraction（XRD）, Fourier transform infrared spectroscopy（FT-IR）, scanning electron microscopy（SEM） and transmission electron microscopy（TEM） methods were used for the characterization of the LDH nanocontainer. The anticorrosion activity of the LDH powders embedded in a hybrid sol-gel coating on aluminum alloy 2024 was investigated by electrochemical impendence spectroscopy（EIS）. The results showed that Ce（III） ions were successfully incorporated into LDHs layers. The sol-gel coating modified with Ce-doped Zn-Al LDHs exhibited higher anticorrosion behavior compared with both unmodified and Ce-undoped LDHs containing coatings, which proved the applicability of Ce-doped LDHs in delaying coating degradation and their potential application as nanocontainers of corrosion inhibitors in self-healing coatings.

Droplet transfer behavior of the stainless steel coated electrode with double-layer coating

In this paper, the droplet transfer behavior of the stainless steel coated electrode with double layer coating is researched by means of those experimental methods, such as high speed camera, collecting droplet in water, surfacing on the steel plate et al. The results show that the droplet transfer indexes of coated electrode are mainly controlled by the size of droplet, which affects the transfer behavior of droplet. The distribution characteristic of the droplet size of the electrode affects the numerical relationship among droplet transfer indexes. The metallurgical process of the coated electrode with double layer coating is carried out continuously in different zones. The main reason for the coated electrode with double layer coating gaining excellent usability quality is that the droplets realize the 'quasi flux wall guided transfer pattern'.

Green corrosion inhibitors intercalated Mg:Al layered double hydroxide coatings to protect Mg alloy

Mg alloy was protected with Mg:Al layered double hydroxide(LDH)coating intercalated with three green corrosion inhibitors(sodium benzoate,3-aminopropyltriethoxysilane and 8-hydroxyquinoline).The in-situ hydrothermal approach was adopted to intercalate corrosion inhibitors into Mg:Al LDH coating.The intercalated Mg:Al LDH coating was successfully acquired,and the crystalline structure of Mg:Al LDH coating was verified with X-ray diffraction(XRD).The organic functional groups of corrosion inhibitors were identified with the help of Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS).The compact and uniform morphology was confirmed by scanning electron microscopy(SEM).The electrochemical measurement revealed better corrosion resistance of corrosion inhibitorintercalated Mg:Al LDH coatings as compared to that of pristine Mg alloy.The corrosion protection mechanism of corrosion inhibitors was described and unearthed the corrosion inhibitor with the best performance.

Acoustic reflection of rib-stiffened double plates coated with a viscoelastic layer

To predict sound-absorbing performance of anechoic materials,the acoustic reflection problem of a viscoelastic layer backed with periodically rib-stiffened infinite double plates is studied in this paper.The reason why structural theories of plates are not applicable to viscoelastic plates is explained through comparing dispersion and attenuation curves of flexural waves with those of Lamb waves.As a result,（visco-）elastic theory is adopted to deal with（visco-）elastic plates,and ribs are treated by structural theories of plates.The coupling between ribs and plates are solved by Hull＇s method,and solution of the reflected field is obtained.The accuracy of present method is validated by comparing with the results by the structural theories of plates.The influence of a backing on the acoustic reflection of the viscoelatic layer is analyzed by computing reflection coefficients.Performances of different viscoelastic materials are evaluated by the average reflection coefficients.The computational results show that,influence of a backing on the acoustic reflection cannot be suppressed by the viscoelastic materials in low frequencies.The resonance is determined by the coupling of the fluid layer and the double plates.And ribs,which are coupled with the double plates,mainly reduce the acoustic reflection.