Zinc Substrate Research Articles

Power law modeling of acoustic cavitation erosion: the hemispherical pit model

A power law model for cavitation erosion is proposed herein that represents volume loss as the creation and subsequent enlargement of hemispherical pits in the surface of the solid. The cumulative volume loss (CVL) of a material is expressed as an Arrhenius term, containing the energy of pit growth, Epg, multiplied by a power law function with the pit radius growth rate, k, as a prefactor and a time exponent, n. The model is verified through fitting of experimental cavitation erosion data for commercially-available aluminum, copper, and zinc substrates, as well as fitting selected data from the International Cavitation Erosion Test and through comparison with other cumulative volume loss models.

High Performance Anti-Corrosion Coatings of Poly (Vinyl Butyral) Composites with Poly N-(vinyl)pyrrole and Carbon Black Nanoparticles.

Zinc is widely used in battery negative electrodes and steel coatings for automotive industries. The anti-corrosion property of zinc is the most important factor determining the performance and lifetime of the products. In this paper, both size-controlled poly N-(vinyl)pyrrole (PNVPY) nanoparticles and carbon black (CB) nanoparticles were compounded with poly (vinyl butyral) (PVB) binder developing a series of composite coatings covered on the zinc substrates using a spin-coating technique. The morphologies of the surface and cross section of the PNVPY/CB/PVB coatings indicate that the PNVPY and CB nanoparticles are uniformly distributed in the matrix. The corrosion resistance of the composite coatings was tested by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization in a 3.5% NaCl solution. It is found that the coating with 1.9 wt.% PNVPY and 2.3 wt.% CB nanoparticles shows a remarkably high resistance value (Rc) and corrosion protection efficiency (99.99%). Meanwhile, the immersion results also reveal its superior corrosion resistance. It is considered that the nanoscale dispersion of PNVPY and carbon in PVB matrix and the strong interface action between the nanoparticles and PVB result in the uniform microstructure of the composites which endues the superior corrosion properties of the coatings.

Fabrication of slippery Zn surface with improved water-impellent, condensation and anti-icing properties

Zinc and its alloys are valuable crucial materials applied in the fields of automobile, ship manufacturing and construction industries. However, their application is limited due to poor performance on water-resistance, condensation and anti-icing property. Slippery liquid-infused porous surface (SLIPS) has been widely used owing to excellent water-repellent, condensation and anti-icing properties. In this work, a SLIPS was fabricated based on zinc substrate by using electrochemical etching, low surface energy modification and lubricant infusion, successively. According to the SEM morphologies and EDS images, it could be confirmed that the rough porous surface structure, low surface energy modification and infused lubricants are key factors accounting for the excellent anti-wetting property of fabricated slippery Zn surface. The experimental results showed that the SLIPS on zinc substrate exhibited outstanding water-repellent performance at a wide range of temperature and drop impact velocity. Moreover, its anti-wetting ability can be sustained even under the impacts of droplets or the continuous water jet. Owing to its dropwise condensation strategy, the SLIPS shows reasonable water collection efficiency, which exceeds 60 mg/(cm2·h) at relative humidity of 90%. The excellent anti-icing property is demonstrated by the simulated ice rain test and deicing force test. And the results showed that only tiny residue ice left on the SLIPS and the deicing force was 2–3 times smaller than ordinary surface. The prepared SLIPS is expected to be an adaptable and efficient method for enhancing the water-repellent, condensation and anti-icing properties of zinc substrate, and may expand the application in energy-efficient fluid handing & transportation, medicine and anti-fouling operating in low temperature environment.

Facile Synthesis of ZnS/ZnO Nanosheets With Enhanced Photocatalytic Activity

ZnS/ZnO heterostructural nanosheets (NSs) are fabricated facilely via a simple solvothermal treatment from ZnS(en)0.5 (en = ethylenediamine) NSs. The synthesized ZnS/ZnO NSs, with a diameter in the range of 150–350 nm and a thickness of 20 nm, grow on the surface of zinc substrate. Structural characterization revealed that both ZnO and ZnS in ZnS/ZnO NSs heterostructure are hexagonal wurtzite crystal structure. The photocatalytic behavior of ZnS/ZnO NSs is scrutinized using rhodamine B (RhB) as probe molecule under UV light irradiation. The result shows that the photocatalytic activity of ZnS/ZnO NSs is markedly enhanced compared to pure ZnS NSs. Moreover, the reusability test indicated that ZnS/ZnO NSs kept high photocatalytic efficiency after five cycles.

Influence of Hot-Dip Galvanised Coating Morphology on the Adhesion of Organic Coatings Depending on the Zinc Bath Pb Content and the Postgalvanising Cooling Method

Hot-dip galvanised coatings used either alone or with an organic coating (duplex system) constitute an effective anticorrosion protection. Adhesion between the coating and the zinc substrate plays a vital role in the durability of the duplex system. Conditions of the galvanising process and alloying additives incorporated into the zinc bath influence mechanical and protective properties as well as thickness, structure, and surface morphology of the zinc coatings. The influence of the surface morphology of zinc coatings on the adhesion of organic coatings was studied. The tests were carried out on zinc coatings produced in baths with varying Pb content and by employing various cooling methods after the galvanising process. It was noted that a rapid cooling in water produces zinc coatings with a fine-grain structure, more suitable for paint application compared to the air-cooled ones, with a spangle.

A tri-layer thin film containing graphene oxide to protect zinc substrates from wear

Due to its excellent properties, Zn alloy is widely used in daily life. However, the poor wear-resisting properties of Zn alloys limits their application. In this paper, a tri-layer thin film consisting of 3-aminopropyltriethoxysilane (APS), graphene oxide (GO) and perfluoropolyethers (PFPE) were successfully prepared on the surface of Zn alloy to improve the wear-resisting properties. The as-prepared tri-layer thin films were characterized by atomic force microscopy, Raman spectroscopy, x-ray photoelectron spectroscopy and contact angle measurement. In addition, the tribological properties of the as-prepared tri-layer thin films were studied on a ball-on-plate tribometer and the morphologies of worn surfaces were observed using 3D noncontact interferometric microscope. Compared with the control samples, the tri-layer thin films showed excellent friction-reducing and wear-resisting properties, which was attributed to the synergistic effect of the GO as the load-carrying layer and the PFPE as the lubricating layer.

Improvement of Adhesion Properties and Corrosion Resistance of Sol-Gel Coating on Zinc.

Corrosion is a major problem for durability of many metals and alloys. Among the efficient classical surface treatments, chromate-based treatments must be banished from industrial use due to their toxicity. At the same time, sol-gel routes have demonstrated high potential to develop an efficient barrier effect against aggressive environments. By this process, the anti-corrosion property can be also associated to others in the case of the development of multi-functional hybrid coatings. In this paper, the main goal is precisely to improve both the corrosion resistance and the adhesion properties of phosphated zinc substrates by the deposition of a hybrid (organic-inorganic) sol-gel layer. To reach this double objective, a choice between two formulations 3-glycidoxypropyltrimethoxysilane (GPTMS)/aluminum-tri-sec-butoxide (ASB) and 3-(trimethoxysilyl)propylmethacrylate (MAP)/tetraethylorthosilicate (TEOS) was firstly made based on the results obtained by microstructural characterizations using SEM, optical analysis, and mechanical characterization such as shock and/or scratch tests (coupled to climatic chamber and salt spray exposure). Several investigations were performed in this study, and the best formulation and performances of the system were obtained by adding a new precursor (1-[3-(trimethoxysilyl)propyl]ureido-UPS) under controlled conditions, as detailed in this paper.

양극산화와 자기 조립 단분자막 코팅 공법을 이용한 아연 기반의 극소유성 표면 제작기술

In this study, we developed a convenient method to achieve superoleophobic surfaces on zinc substrates by using anodization and self-assembled monolayer coating, and to facilitate the fabrication of superoleophobic surfaces having reentrant structures, even for lower surface tension liquids than 30 mN/m- including hexadecane (γ = 27.5 mN/m). The liquid repellency of the structured surface was validated through observable experimental results; contact angle measurement. The optimal anodizing condition was determined as a critical parameter in building the superoleophobicity. The re-entrant had nanowire/microball structures formed by anodization with a high voltage. Under an optimized morphology by re-entrant structures with fluorination treatment, the contact angle over 150o is achieved, even for hexadecane.

In-Operando Surface Chemistry of Nickel and Copper Current Collectors During Zinc Electro-Deposition and Dissolution

Zinc electrodeposition from alkaline solutions is of renewed interest due to MnO2-Zn and Ni-Zn grid-scale energy storage devices. Control and understanding of the rechargeable zinc electrode remains difficult, and several Zn battery technologies suffer from a failure to deposit zinc after many cycles. The predominant substrates for zinc energy storage in zinc electrodes are copper and nickel. Here we study the performance of zinc electrodeposition onto nickel and copper substrates in an alkaline battery device, with the aim to identify the nanoscale surface chemistry that mediates the decreased electrodeposition performance. We find the coulombic-efficiency of the zinc cycling process to drop from 99% to ~50% under various operating conditions for electrodeposition, for both zinc and copper substrates. We present grazing-incidence x-ray diffraction measurements in-operando on the nickel surface, to identify the crystallography of nanoscale surface layers that form during cycling of the battery. Our results suggest the presence of zinc oxide and zinc peroxide layers on the nickel surface affects the coulombic efficiency of zinc cycling. We find that nanoscale layers of zinc oxide aids the zinc electrodeposition and allows charge-efficiency to be high. If the nickel anode surface is exposed to voltages ~0.5 V above zinc’s rest voltage this zinc oxide layer disappears, leaving behind a relatively bare nickel surface that has very poor zinc electrodeposition charge-efficiency due to nickel’s catalytic generation of hydrogen gas. The beneficial zinc oxide layer is seen to grow thicker during normal cycling and during open circuit rest over many hours. Similar performance problems are shown for copper current collectors. X-ray photoelectron spectroscopy and electron microscopy is performed on the copper current collectors, which uncovers the formation of a composite zinc-copper nanoscale layer that impedes zinc electrodeposition during battery charging. Electrochemical growth and dissolution of this zinc-copper layer is hypothesized to interact with shape change of the zinc electrode. In the case of both copper and nickel the formation of these layers is caused by undesired oxidation that arises due to microscopic variations in OH- and H2O concentration. Possible strategies for improving the long-cycle performance of zinc electrochemical energy storage are given.

Development and characterisation of zinc oxalate conversion coatings on zinc

The interactions between oxalic acid and zinc substrates have been studied through the deposition of zinc oxalate coating by immersion. The corrosion behaviour of zinc was investigated by surface observation and electrochemical impedance spectroscopy (EIS). Better protective properties were observed for samples treated with 10−1 M oxalic acid compared to other concentrations and the enrichment of corrosion product by Na was observed. The electrochemical results reveal that the oxalate coating increases corrosion protection in corrosive medium. It is proposed that the zinc oxalate coating formed act as a basis for anchoring zinc corrosion products forming simonkolleite improving corrosion resistance.

Fabrication of bismuth superhydrophobic surface on zinc substrate

The dendritic Bi/Bi2O3/ZnO superhydrophobic surface (SHPS) was facilely obtained on zinc substrate via etching in 0.5 mol L−1 HCl solution for 2 min, immersing in 2 mmol L−1 Bi(NO3)3/0.1 mol L−1 HNO3 solution for 2.5 min and annealing treatment at 180 °C for 2 h. The wetting property results demonstrated that the superhydrophobic sample had excellent water-repellency with a static water contact angle of ~ 160° and sliding angle of ~ 0° under the optimum condition, which can be visually confirmed by the impacting droplet could rebound back immediately and roll off the horizontally placed sample. Moreover, it exhibited remarkable self-cleaning ability, buoyancy, desired stability in long-term storage in air, corrosion resistance in 3.5 wt% NaCl solution, ice-over delay at − 16 °C and durability in lab-simulated abrasion test.

Cathodic Corrosion of Zinc under Potentiostatic Conditions in NaCl Solutions

AbstractZinc electrodes were polarized cathodically at moderate overpotentials in NaCl 0.6 M solutions under potentiostatic conditions for 7 to 17 hours at room temperature. Corrosion products were characterized by using optical microscopy, XRD, Raman microscopy, XPS, and FIB‐SEM. Close to the open‐circuit potential, the corrosion products were formed by simonkolleite and the electrochemical response exhibits anodic features. At more negative potentials, the current density remains cathodic throughout the polarization and the deposits on the electrode surface consist almost solely of ZnO. The soluble zinc species necessary for ZnO deposition originate from localized dissolution of the substrate in the form of pits. This effect is assigned to the strong alkalinization of the surface due to oxygen reduction. Despite developing greater surface area than bare zinc substrates, the nanostructured ZnO deposits reduced the cathodic activity.

Characterization of Cinnamyl Alcohol Dehydrogenase gene family in lignifying tissues of Tectona grandis L.f.

Abstract The cinnamyl alcohol dehydrogenase (CAD) enzyme catalyzes the last step of monolignols synthesis in the lignin pathway. Tectona grandis (teak) is a tropical tree with high valuable tim­ber. As there is few genetic information about lignin formation in teak, the purpose of this study is to characterize members of CAD family in this species. As methodology, PCR amplification using cDNA samples, vector cloning, sequencing, bioinforma­tics analyses and gene expression studies using real time RT-qPCR were performed. As results, four members (TgCAD1- TgCAD4) were obtained. Comparative analyses showed that all of them have conserved residues for catalytic zinc action, structural zinc ligation, NADPH binding and substrate specifici­ty, consistent with the mechanism of alcohol dehydrogenases. Phylogenetic analysis showed that TgCADs are present in three main classes and seven groups. Expression analyses revealed that TgCAD1 was highly expressed in leaves and could be rela­ted with pathogen defense. TgCAD2 was more expressed in branches and roots. Differently, TgCAD3 and TgCAD4 were highly expressed in juvenile and mature sapwood, suggesting a crucial role in wood development and lignin biosynthesis, with tissue-specialized expression profiles. Furthermore, TgCAD4 could be related with teak maturation for being more expressed in sapwood of mature teak trees. As conclusion, this work is the first to characterize genes of CAD family in Tectona grandis. These genes could be interesting to develop transge­nic plants for basic research and field applications.

Structure and Formation of Trivalent Chromium Conversion Coatings Containing Cobalt on Zinc Plated Steel

The present study intends to elucidate the effect of treatment solution composition on the formation and structure of Trivalent Chromium-based Conversion (TCC) coatings containing cobalt on zinc substrates. Model solutions with two different complexing agents, viz. fluoride and oxalate, with and without cobalt were applied to zinc plated steel. The scanning electron microscopy and atomic force microscopy images revealed a morphology with microstructural defects that can be improved to a more uniform and adherent structure by adding cobalt to the passivating bath. The elemental composition of the layer was investigated by auger electron spectroscopy (AES). Furthermore, the amounts of Cr and Co in the coatings were also measured with the aid of inductively coupled plasma optical emission spectroscopy (ICP-OES). In good agreement with AES, cobalt was also detected in the layers via ICP-OES measurement. The results of accelerated corrosion tests suggested that the formation of a densely packed layer is crucial for a good corrosion resistance of the coating.

A robust and repairable superhydrophobic Co5Zn21 alloy surface on a zinc substrate

Repairable Co5Zn21 superhydrophobic surface was successfully prepared on zinc substrate and showed good corrosion resistance and antifriction.

Hierarchically ZnIn2S4 nanosheet-constructed microwire arrays: template-free synthesis and excellent photocatalytic performances.

Hierarchically ZnIn2S4 nanosheet-constructed microwire arrays (NCMAs) on a zinc substrate have been synthesized for the first time through a one-step solvothermal method without using any template or surfactant. The as-synthesized ZnIn2S4 microwires are constructed by vertical nanosheets preferentially exposing (006) facets, which are about 1-5 μm in diameters and larger than 10 μm in average length. Experimental results demonstrate that the hierarchically ZnIn2S4 NCMAs are converted from intermediate components of single crystalline indium nanowires, which are generated along the direction of (101) planes by a displacement reaction between Zn and In3+ during the initial synthesis process. This conversion of indium nanowires to hierarchically ZnIn2S4 NCMAs has been explained by a novel corrosion-exchange-self-assembly mechanism, which might indicate a novel strategy for preparing other ternary sulphide nano-microwire arrays. The prepared ZnIn2S4 NCMAs are used as photocatalysts, demonstrating effective photocatalytic degradation activity for diverse organic pollutants including different dyes, tetracycline and 2,4,6-tribromophenol (2,4,6-TBP). This efficient photocatalytic activity is ascribed to the strong absorption of ZnIn2S4 NCMAs in a wide range from ultraviolet to visible light as well as the preferentially exposed (006) facets of ZnIn2S4 nanosheets.

Development of Nanocomposite Based Miniaturized S-band Antenna for Novel Substrate Materials

The selection of appropriate substrate material acts as a performance regulator for miniaturized nanocomposite rectangular micro strip patch antenna. The substrate material not only controls the transport properties of nanocomposites but also influences the resonant properties of the nanocomposite rectangular micro strip patch antenna. The coaxial fed micro strip line nanocomposite rectangular patch antenna is designed here for operating in s-band frequency range (2.2–3.8 GHz) for wireless applications. The performance is investigated for cobalt nickel, cobalt zinc, cobalt ferrite, silica and quartz substrate materials on the basis of return loss, voltage standing wave ratio (VSWR), absorption cross section, and bandwidth and radiation efficiency. The comparison of results shows that a novel magneto-metal-dielectric-polymer-nanocomposite Exhibits overall excellent performance by the virtue of having higher bandwidth and radiation efficiency as compared to other chosen substrate materials. The simulations were carried out by using IE3D electromagnetic software which utilizes (MOM) method of moment technique.

Preparation of Ag superhydrophobic surface on metal substrates

In this work, the facile approaches are developed for preparation the Ag superhydrophobic surfaces (SHSs) on zinc (Zn), copper (Cu) and aluminium (Al) substrates. The water contact angles (WCAs) of the Ag SHSs on Zn, Cu and Al substrates are 167°, 165° and 154°, respectively. Furthermore, the water sliding angle (WSA) of each surface is less than 1°. The morphology and chemical composition of the samples are characterized using scanning electron microscopy (SEM) and X-ray diffraction pattern (XRD). The as-prepared three kinds of SHSs possess the self-cleaning performance, which can quickly take the chalk away when the water droplets fall down the SHSs. In addition, the superhydrophobicity of the SHSs can well maintain after exposure to the air for 6 months, indicating that the surfaces can sustain good stability.

ZnO nanoplate clusters with numerous enlarged catalytic interface exposures via a hydrothermal method for improved and recyclable photocatalytic activity

To promote the photodegradation rate of hazardous pollutants in aqueous solution, enlarging the effective catalytic interface of the photocatalysts is one of the efficient ways for environmental purification. However, the photocatalysts could not exhibit superior photocatalytic performances unless the exposing extent to the environment of the enlarged catalytic interfaces was taken into account. Here, a facile hydrothermal synthesis of a large-scale and highly efficient photocatalyst composed of ZnO nanoplate clusters with steric exposing catalytic interfaces of (001) planes is demonstrated. The aluminum ions are used as the capping agent to suppress the familiar preferred c-axis orientation and facilitate the polar surface growth of ZnO. The steric exposing structure is related to the suppressed effect of the aluminum ions on the double nucleation and growth process which occur both on substrate and in solution. Large-scale nanoplates aggregated in clusters are successfully prepared on a zinc substrate, permitting easy recycle of the photocatalysts. Surprisingly, ZnO nanoplate clusters exhibit a fourfold enhanced photodegradation rate than that recorded for the pure ZnO nanorod arrays under UV irradiation. The demonstrated higher photodegradation rates and recyclability indicate that ZnO nanoplate clusters are candidates for efficient photocatalysts, replacing the traditional nanoparticle photocatalysts.

Fabrication of non-wetting surfaces on zinc surface as corrosion barrier

Two kinds of non-wetting surfaces, super-hydrophobic surface (SHS) and slippery lubricant-infused porous surface (SLIPS), were fabricated on zinc surface with hydrothermal method. Their surface properties were characterized with FE-SEM, XRD, XPS and contact angle meter, and their corrosion protection performances were evaluated with electrochemical measurements. It was demonstrated that both kinds of surfaces present high corrosion resistance to the underlying zinc substrate for the air (or lubricant) layer trapped in film. In comparison with SHS, the SLIPS presents advantage in maintaining stability in corrosive medium. This research provides guidance for the selection of non-wetting surface in practical corrosion protection application.