Superhydrophobic zinc oxide/epoxy coating prepared by a one-step approach for corrosion protection of carbon steel

Corrosion in carbon steel (CS) has been an existing issue and it calls attention to the need for improved corrosion protection. At present, superhydrophobic (SHB) coating technology has piqued the interest of researchers as alternative means of mitigating metal corrosion. Herein, a one-step solution deposition process was used to prepare an SHB coating based on nano-zinc oxide/epoxy (ZnO/EP) on CS and its corrosion resistance performance was analyzed by the means of electrochemical analysis and compared with that of the blank CS metal and the regular coatings (plain EP and regular ZnO/EP). Results implied the as-prepared SHB coating shows remarkable improvement in corrosion protection for the substrate. Notably, it exhibited higher in both impedance modulus (|Z|) and coating resistance (Rc) results approaching 1010 Ωcm2, than those of regular coatings by 3 orders of magnitude to that of plain EP (∼107 Ω cm2), and 1 order of magnitude to regular coating (∼109 Ω cm2), indicating its superior corrosion resistance performance. Besides that, the superior inhibitive effect of the SHB ZnO/EP (ZES) is also proven by the potentiodynamic polarization (PDP) results, in which the Icorr value is suppressed down to 2.08 × 10−11 A/cm2, thereby achieving an excellent corrosion rate result of 3.38 × 10−11 mm/year. The exceptional barrier protection is ascribed to the presence of a stabilized air interlayer captured within the coating/electrolyte interface thus effectively blocking the penetration of electrolyte into the coating. This facile yet effective one-step processed SHB coating offers an effective route to improve the corrosion resistance performance of the CS metal and thereafter expand its potential applications

Effects of silica on mechanical and rheological properties of EPDM-based magnetorheological elastomers

Magnetorheological elastomers (MREs) are a kind of emerged smart material, where its responsive moduli in terms of mechanical and rheological properties are largely influenced by the presence of an external magnetic field. However, the incompatibility on the surface properties of its raw materials (fillers and matrix) may deteriorate the required properties of MREs. Therefore, in this study, the innovation of MRE by embedding silica nanoparticles as an additive has been experimentally investigated to strengthen the interactions between filler and matrix, thus resulted in enhancement of mechanical and rheological properties of MRE. The ethylene propylene diene monomer (EPDM)-based MREs were fabricated by mixing the EPDM with carbonyl iron particles (CIPs) as the main filler and different contents of silica nanoparticles (0 wt%–11 wt%) as an additive. The microstructures, magnetic properties and tensile properties of isotropic EPDM-based MREs were observed by using field emission scanning electron microscopy, vibrating sample magnetometer and Instron Universal Testing Machine, respectively. Meanwhile, the rheological properties were examined under oscillatory loadings in the absence and presence of magnetic field using rotational rheometer. The experimental results showed that the silica nanoparticles play a significant role in improving the properties of EPDM-based MREs. The adhesiveness of silica into CIPs has amended the interfacial interactions between CIPs and matrix by occupying the gaps between distributed CIPs within the MRE. Consequently, the addition of 11 wt% silica has not only improved the tensile properties (tensile strength and elongation at break), but also enhanced the MR effect compared to EPDM-based MREs without silica. Thus, incorporation of silica nanoparticles as an additive in EPDM-based MRE has the potential to be further explored and compromised to bring new innovation in real engineering applications

Glassy NiTi produced with different cooling times: Structural investigation using molecular dynamics simulations

In this research we investigate the structure of glassy NiTi using molecular dynamics simulations. The final configurations are obtained by decreasing the temperature of liquid NiTi rapidly from 2500 K to 300 K, with various cooling times from 0.1 ns to 2.0 ns. We found that the height of the peak values for structural factors slightly increases with an increase in cooling time. From the analysis of local atomic packing using the bond-angle method, we also find that the count of hexagonal close packed (HCP)-like structure drops at the longer cooling time, a finding which is contrary to the trend for body-centered cubic (BCC)-like and icosahedral short-range order (ISRO) structures. It is also observed that face-centered cubic (FCC)-like structure is insensitive to change in cooling time

Glassy NiTi produced with different cooling times: Structural investigation using molecular dynamics simulations

In this research we investigate the structure of glassy NiTi using molecular dynamics simulations. The final configurations are obtained by decreasing the temperature of liquid NiTi rapidly from 2500 K to 300 K, with various cooling times from 0.1 ns to 2.0 ns. We found that the height of the peak values for structural factors slightly increases with an increase in cooling time. From the analysis of local atomic packing using the bond- angle method, we also find that the count of hexagonal close packed (HCP)-like structure drops at the longer cooling time, a finding which is contrary to the trend for body-centered cubic (BCC)-like and icosahedral short- range order (ISRO) structures. It is also observed that face-centered cubic (FCC)-like structure is insensitive to change in cooling time

Glassy NiTi produced with different cooling times: structural investigation using molecular dynamics simulations

In this research we investigate the structure of glassy NiTi using molecular dynamics simulations. The final configurations are obtained by decreasing the temperature of liquid NiTi rapidly from 2500 K to 300 K, with various cooling times from 0.1 ns to 2.0 ns. We found that the height of the peak values for structural factors slightly increases with an increase in cooling time. From the analysis of local atomic packing using the bond-angle method, we also find that the count of hexagonal close packed (HCP)-like structure drops at the longer cooling time, a finding which is contrary to the trend for body-centered cubic (BCC)-like and icosahedral short-range order (ISRO) structures. It is also observed that face-centered cubic (FCC)-like structure is insensitive to change in cooling time

Thermal analysis of kenaf sandwich panel

The introduction of the eco-core sandwich panel composite is contributing a new approach to the designer to achieve high performance and light weight. In this research project, the new kenaf eco-core sandwich panel will be developed and then laminated with galvanized steel. The final goal is to find the optimum eco-core metal matrix composite sandwich structure with maximum mechanical properties such as stiffness and buckling. Kenaf eco-core sandwich will be fabricated and study on the interaction between eco-core sandwich panel and metal faces will be performed. The characterization of the eco-core sandwich panel will be done using different analytical tools. This study would provide a way to enhance the application of this new eco-core metal matrix composite sandwich structure. The amount of sample used was approximately 12 mg. The temperature profile was from 27°C to 1000°C at a heating rate of 10°C/min. In this study, result shows that degradation of composites starts to occur at about 180°C. Increasing the kenaf percent ratio will decrease the percent residue

Mechanical properties of kenaf core sandwich panel toughened with modified epoxy

Kenaf-core sandwich panels were prepared by hand lay-up method with the optimum characteristics. The aim of this study is to determine the effects of modified epoxy on the mechanical properties of the sandwich panel. Mechanical test such as flexural, drop impact and tensile test were performed to investigate the optimum system of kenaf-core sandwich panel within 0-5wt% of kenaf fiber content. It revealed that the optimum loading of kenaf fiber was at 3wt%. Furthermore, this system was studied with the incorporation of liquid natural rubber (LNR) as impact modifier. All tests have been carried out according to the ASTM 365, C297, C393, and D1736. Each final data point is an average value that has been obtained based on a statistical sampling of four specimens. The main element of core structure is kenaf and the skin used in this study is aluminium type 1100. According to compression, flatwise tensile, three point bending and drop impact tests, 3wt% of LNR content exhibit as an excellent impact modifier, in modifying the mechanical properties due to rubber toughening. In addition of too much liquid natural rubber more than 5wt% was substantially interrupted the system

Effect of nanoparticles on wettability of nanocoating on carbon steel

Nanocoatings plays an important role in coating industry. The solution was being prepared through copolymerization of epoxy resin hardener and with the incorporation of metal oxide nanoparticles, Zinc Oxide (ZnO) and Silica (SiO2). ZnO and SiO2 were synthesized using sol-gel. Epoxy hardener acted as host while the metal oxide nanoparticles as guest components. The formulation of nanocoatings with excellent adhesion strength and corrosion protection of carbon steel was studied. The performance of wetting ability with different medium was analysed using contact angle. Water medium showed the addition of 3wt% of hybrid between ZnO and SiO2 was the best nanocoating to form hydrophobic surface and was also the best nanocoating surface to form hydrophilic surface with vacuum oil dropping. In oil dropping, the contact angle was smaller than 90° and the water drop tends to spreads on surface

Graphene oxide microcapsules (GOMs) with linseed oil core via Pickering emulsion method effect of disperse speed

Graphene oxide microcapsules (GOMs) have been prepared through Pickering emulsion method by varying the disperse speed to study its effect on the GOM’s size. The GOMs were characterized through phase separation observation, polarized optical microscope (POM), and particle size analyser (PSA). Phase separation observation showed more viscous and cloudy emulsion was produced when the disperse speed was increased. After 24 hours, only 800 rpm emulsion did not show any phase separation. POM characterization depicted that increasing the emulsification energy led to the finer emulsion with the 1200 rpm sample showing the smallest microcapsule size of around 8 μm. However, PSA analysis suggested that although the disperse speed controls the GOMs size, the amount of GO in the emulsion plays an important role for the microcapsule to maintain its stability. Emulsion produced at 800 rpm possesses satisfactory stability with GOMs diameter of 11.15 μm. The result also suggested that graphene oxide encapsulated linseed oil may act as a promising candidate for healing microcapsules in a self-healing coating system. ******************************************************************************** Mikrokapsul graphene oksida (GOMs) telah dihasilkan melalui kaedah emulsifikasi Pickering dengan memvariasikan tenaga pengemulsi untuk mengkaji kesannya terhadap saiz GOMs. GOMs dicirikan melalui pemerhatian pemisahan fasa, mikroskop optik polarisasi (POM) dan penganalisis saiz zarah (PSA). Pemerhatian pemisahan fasa menunjukkan emulsi yang lebih likat dan keruh dihasilkan apabila kelajuan pengemulsi meningkat. Selepas 24 jam, hanya emulsi 800 rpm tidak menunjukkan pemisahan fasa. Pencirian POM meunjukkan bahawa peningkatan tenaga pengemulsi menghasilkan emulsi yang lebih halus dengan sampel 1200 rpm menunjukkan saiz mikrokapsul terkecil, sekitar 8 μm. Walau bagaimanapun, analisis PSA mencadangkan bahawa walaupun kelajuan pengemulsi mengawal saiz GOMs, jumlah GO dalam emulsi memainkan peranan penting untuk mengekalkan kestabilan mikrokapsul. Emulsi yang dihasilkan pada 800 rpm mempunyai kestabilan yang memuaskan dengan purata saiz GOMs sekitar 11.15 μm. Berdasarkan dapatan kajian, graphene oksida yang terkandung minyak biji rami boleh menjadi salah satu mikrokapsul penyembuh dalam sistem cat auto-sembuh