TiO2 Particles Research Articles

EVOLUTION OF WEAR AND CORROSION RESISTANCE OF Bi ALLOY-LAMINATED Al/TiO2 COMPOSITE STRIPS FABRICATED VIA APB PROCESS

In this study, Bi alloy AA1100/TiO2/AA5083 composites were produced by accumulative press bonding (APB) for the first time. In the first step, two bars of aluminum alloys 1100 and 5083 with 5[Formula: see text]wt.% of uniformly scattered TiO2 particles were stacked together and pressed with a 50% reduction ratio. Then, this process was continued up to six steps. Corrosion properties of composites were studied by potential dynamic polarization and electrochemical impedance spectroscopy measurement in 3.5[Formula: see text]wt.% NaCl solution. So, in this investigation and as its novelty, a considerable improvement was revealed in the main electrochemical parameters as a result of enhancing the influence of APB steps and the inert character of the particles. Moreover, using the wear test, the wear resistance of these bi alloy composites has been studied vs the APB steps. Also, the wear and electrochemical experiments showed that corrosion and wear resistance of samples were improved by the APB steps by 70% and 34%, respectively.

Assessment of TiO2 (nano)particles migration from food packaging materials to food simulants by single particle ICP-MS/MS using a high efficiency sample introduction system

TiO2 is the most widely used white pigment in plastics and food packaging industry, thus the question of its migration towards food and hence the impact on consumers is raised. Since recent research indicate its potential toxicity, it is necessary to study TiO2 contamination as a consequence of food storage. For this purpose, plastic containers from commercially-available dairy products and custom-made TiO2-spiked polypropylene materials were put in contact with 50% (v/v) ethanol and 3% (w/v) acetic acid, which were used here as food simulants. The migration assays were carried out under standard contact conditions of packaging use (as recommended by Commission Regulation (EU) N° 10/2011 for food contact migration testing), and under conditions of extreme mechanical degradation of the packaging. The TiO2 (nano)particles released in the food simulants were analysed by single particle inductively coupled plasma-tandem mass spectrometry in mass-shift mode and using a high efficiency sample introduction system (APEX™ Ω) to avoid matrix effects from food simulants. For the dairy product containers and for the spiked polypropylene, results showed release of TiO2 particles of rather large sizes (average size: 164 and 175 nm, respectively) under mechanical degradation conditions, i.e. when the polymeric structure is damaged. The highest amounts of TiO2 were observed in 50% ethanol after 10 days of storage at 50 °C (0.62 ng cm−2) for the dairy product containers and after 1 day of storage at 50 °C (0.68 ng cm−2) for the spiked polypropylene. However, the level of Ti released in particle form was very small compared to the total Ti content in the packaging and far below the acceptable migration limits set by European legislation. Release under standard contact conditions of use of the container was not measurable, thus the migration of TiO2 particles from this packaging to dairy products among storage is expected to be negligible.

Modeling titanium dioxide (TiO2) nanoclusters using a 2D sectional method with molecular dynamics (MD) determined coagulation rates

Accurate prediction of the particle size distribution (PSD) evolution of growing nanometer scale particles is important in designing gas-phase synthesis reactors for the production of nanomaterials. Towards improved predictions of growth, we model the evolution of the PSD of 1-4 nm TiO2 particles from the decomposition of titanium tetraisoproxide (TTIP) using a two-dimensional (2D) sectional method, uniquely with coagulation rates derived from molecular dynamics (MD) trajectory calculations which account for detailed particle–particle interactions. The PSDs predicted by the 2D sectional method are compared to recent experimental measurements of PSDs in the 1-3 nm range in a flow tube reactor. The nucleation of particles is modeled based on prior mobility measurements of ions attributed to TTIP and their decomposition, with the specific nucleation rate here fitted as a fraction of base nucleation rate (k) derived from these prior measurements. In the 2D sectional model, we examine the influence of the initial (nucleated) particle charge distribution on the PSD, with different coagulation rate coefficients for neutral-charged and charged-charged particle collisions. With the MD-derived coagulation rate coefficients, we find that using nucleation rate coefficients between 0.005k and 0.03k leads to strong agreement between modeled PSD and measured PSD for a wide variety of experimental residence times, initial TTIP concentrations and temperatures. Increasing the charge fraction from 0% (uncharged) to 80% (bipolar) does not result in a significant change in the PSD, because the particles rapidly self-neutralize through coagulation based on the simulation results. The results with MD-derived coagulation rate coefficients are compared to those of the sectional method with classical kinetic theory of gases (KTG) rates with a constant enhancement factor to account for potential interactions. Through comparison, we find that the predictions from the classical KTG model consistently exhibit weaker coagulation rates than the MD-derived model during the PSD evolution.

Microstructure and high-temperature oxidation resistance of in-situ Al2O3 reinforced AlCrFeTiV high-entropy alloy with boron microalloying

In this study, the effect of boron (B) on the microstructure and high-temperature oxidation resistance of AlCrFeTiV high-entropy alloy (HEA) coatings were investigated via laser cladding on Ti-6Al-4 V. The study findings indicate that AlCrFeTiVBx (x=0, 0.5, and 1 at%) HEAs coatings mostly comprise BCC solid solution phase, TiO2 and Al2O3 ceramic particles, which formed by oxygen (O) in the air reacts with Titanium (Ti) and Aluminum (Al) of coatings. Besides, the introduction of minor B should effectively reduce the formation of TiO2. Increasing the B content, significantly promoted the high-temperature oxidation resistance of HEAs coatings at 900 °C for 50 h. When x = 1, the coating exhibits the best high-temperature oxidation resistance. Furthermore, the oxidation mechanism of the coating was studied using first-principles calculations, and further investigation was utilized on the charge transfer of oxygen adsorbed on the BCC (1 0 0) surface.

Effectiveness of natural dye adsorption on ILSS and optical properties of bio synthesised TiO2 nano particles and reinforced with flax seed fiber/epoxy based hybrid composites

The study explores how dyes can improve the strength and optical properties of composites made from flax seed fiber and epoxy, which are incorporated with biosynthesised TiO2 nanoparticles derived from the Curcuma longa plant. The TiO2 nanoparticles were produced using a synthesis method that involved curcumin from Curcuma longa as a reducing and stabilizing agent. By introducing dyes to these composites, it enhances the bonding between layers. Optimizes their ability to absorb UV light. The research findings analyze how the ILSS (interlaminar shear strength) improves by adding natural dye additives and measurable enhancements in their optical characteristics. The results indicate that composite materials containing 5 wt% of nanoTiO2 exhibit the ILSS value (52.31 MPa). This is because the TiO2 particles are evenly distributed throughout the substance at this concentration. The crystal orientation and size (71.02 nm) of biosynthesized TiO2 nanoparticles were determined using X-ray diffraction techniques. Regarding optical properties, observations were made across a wavelength range of 450–2300 nm. Compared to a surface, it was observed that incorporating dyes into adsorbents led to increased absorption and reduced transparency across light wavelengths. This study offers insights into the uses of composites infused with natural dyes in sustainable engineering and materials that protect against sunlight.

Titania/graphene nanocomposites from scalable gas-phase synthesis for high-capacity and high-stability sodium-ion battery anodes

In sodium-ion batteries (SIBs), TiO2 or sodium titanates are discussed as cost-effective anode material. The use of ultrafine TiO2 particles overcomes the effect of intrinsically low electronic and ionic conductivity that otherwise limits the electrochemical performance and thus its Na-ion storage capacity. Especially, TiO2 nanoparticles integrated in a highly conductive, large surface-area, and stable graphene matrix can achieve an exceptional electrochemical rate performance, durability, and increase in capacity. We report the direct and scalable gas-phase synthesis of TiO2 and graphene and their subsequent self-assembly to produce TiO2/graphene nanocomposites (TiO2/Gr). Transmission electron microscopy shows that the TiO2 nanoparticles are uniformly distributed on the surface of the graphene nanosheets. TiO2/Gr nanocomposites with graphene loadings of 20 and 30 wt% were tested as anode in SIBs. With the outstanding electronic conductivity enhancement and a synergistic Na-ion storage effect at the interface of TiO2 nanoparticles and graphene, nanocomposites with 30 wt% graphene exhibited particularly good electrochemical performance with a reversible capacity of 281 mAh g−1 at 0.1 C, compared to pristine TiO2 nanoparticles (155 mAh g−1). Moreover, the composite showed excellent high-rate performance of 158 mAh g−1 at 20 C and a reversible capacity of 154 mAh g−1 after 500 cycles at 10 C. Cyclic voltammetry showed that the Na-ion storage is dominated by surface and TiO2/Gr interface processes rather than slow, diffusion-controlled intercalation, explaining its outstanding rate performance. The synthesis route of these high-performing nanocomposites provides a highly promising strategy for the scalable production of advanced nanomaterials for SIBs.

Composites based on polymeric blends reinforced with TiO2 modified aramid fibers

AbstractThe paper presents a study on composites based on 50:50 (PP:LLPE‐g‐MA) reinforced with 0.5, 1, and 2 wt% aramid fibers unmodified/modified with TiO2, processed by melt compounding. Micronic aramid fibers were acetone washed to remove impurities and treated with Ti(IV)isopropoxide precursor via sol–gel method, adding microcellulose for TiO2 particle dimension control. Composites were hot‐pressed into 4 mm‐thick plates for sampling and 0.5 mm‐thick sheets for thermoforming. All composites were successfully thermoformed, fibers‐based samples showing improved thermoforming ability without wrinkling. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Energy dispersive X‐ray spectroscopy (EDS) analysis confirmed the formation of TiO2 particles on the fiber surface. Optical microscopy, SEM and FTIR analysis exhibit the fibers' strong embedment into the matrix due to physical interlocking, generating surface defect reduction. Water absorption decreased from 0.195% (control) to 0.075 and 0% for 1 TiO2 and 2 TiO2 samples, due to material compactization. Contact angles increased from 95.18° (Control) to 108° (1 TiO2) and 112.89° (2 TiO2). The highest flexural strength and modulus were exhibited by 1 TiO2 sample that increased by 44.88% and 47.6% compared to the control sample, due to higher intrinsic rigidity of fibers and TiO2 modifying surface rugosity and phase interaction. The impact strength of the control sample improved by 139% compared to PP due to brittleness reduction, 1 TiO2 by 209% compared to PP, 29% compared to the control sample. The results and excellent thermoformability recommend the materials for encapsulation of electronic/expensive parts in automotive or drone applications, offering viable, facile, rapid, and cost‐effective solutions to easily replace damaged parts.Highlights Aramid fibers were successfully modified using isopropoxide precursor; Strong embedment of fibers in the polymer diminishes crack propagation/damage; Improved impact and bending properties and water contact angle; The composites showed a high ability to thermoform into complex shapes; Potential to replace non‐reusable materials as encapsulation solutions.

Green fabrication of CuO-egTiO2 composite for photodegradation of organic pollutant under direct visible light illumination

A (CuO-egTiO2) composite coated with copper oxide has been manufactured as a green and facile photocatalyst via Argyreia nervosa leaf extract. The photocatalyst consists of equaixial geometry (egTiO2) particles with copper oxide (CuO) nanocrystals deposited on the TiO2 surface in varying proportions. The structural, morphological, and optical properties of the CuO-egTiO2 photocatalyst nanostructures were inspected via various techniques, through (XRD), (FE-SEM), (DRS), (BET) analysis, (PL) spectra, and (TEM). The results obtained revealed the non-uniform growth of CuO nanocrystals on the surface of TiO2 particles, resembling a (core–shell) structure. The photocatalytic activity of the CuO-egTiO2 nanocomposite was verified in the degradation of Rhodamine B dye (RhB) using an inhomogeneous photocatalytic activation process, with CuO-egTiO2 (10 %) proving to be the most effective photocatalyst under visible light. The effect of the catalyst quantity within concentrations of 0.3–1.8 g/L was studied by exposing aqueous solutions containing the photocatalysts to visible radiation. The dye removal rate was estimated by calculating the remaining concentration, indicating a pseudo-first-order disappearance model with a dye removal percentage of 95.20 %. Additionally, the impact of reactive oxygen species (ROS) types was investigated, The highest photocatalytic degradation rate of 52.16 % was observed when using the inhibitor (EDTA), indicating that the active group contributing to the photocatalytic degradation of RhB is hydroxyl radicals (●OH). At last, in reuse experiments, it was demonstrated that the CuO-egTiO2 (10 %) photocatalyst maintained a remarkable 75.3 % of its initial efficiency even after being recycled for four cycles.

Coupling static multiple light scattering (SMLS) analysis with the Hansen approach for the rationalization of the dispersibility and colloidal stability of TiO2 particle dispersions

While the characterization of dispersibility and colloidal stability remains a key step in many formulation processes, these notions are still confused, and colloidal stability is often interpreted as a direct consequence of dispersibility. In this study, Static Multiple Light Scattering (SMLS) measurements and the predictive Hansen approach are combined to distinguish and characterize the dispersibility and the colloidal stability of TiO2 P25 particles dispersed in pure and mixture of solvents. To this aim, an experimental protocol is proposed using fast time resolved SMLS measurements at a fixed height to assess suspension dispersibility under mechanical stirring as well as space and time resolved SMLS measurements of the suspension stability at rest. Dispersibility is quantified through a Dispersibility Index (DI) depending on the mean diameter of particles and transmission or backscattering signals standard deviation measured with SMLS under mechanical stirring. Quantification of colloidal stability is obtained from a Relative Turbiscan Stability Index (RTSI) measured at rest. Scoring of solvents is performed using the DI and the RTSI to build Hansen dispersibility and stability spheres respectively. It is found that the dispersibility and the stability spheres are clearly separated arguing that a lower colloidal stability is not necessarily a consequence of a poor dispersibility. Beyond this clarification, this combined SMLS-Hansen approach is a major step toward the optimization of dispersibility and stability of formulations. It can be also intended to find better dispersion media, greener and cheaper solvents to optimize particles suspensions, to reduce the content of costly stabilizing additive or to satisfy product regulatory requirements evolution.

Designed Mesoporous Architecture by 10–100 nm TiO2 as Electron Transport Materials in Carbon-Based Multiporous-Layered-Electrode Perovskite Solar Cells

Fully printable carbon-based multiporous-layered-electrode perovskite solar cells (MPLE-PSCs) are easy to fabricate and have excellent durability. In this study, the porosity of the mesoporous TiO2 layer as the electron transport layer in MPLE-PSCs was controlled by varying the particle diameter of TiO2 nanoparticles from 14 nm to 98 nm. Furthermore, the results of absorbed photon-to-current conversion efficiency, visible light reflectance spectroscopy, pore-size distribution, X-ray diffraction, field emission scanning electron microscopy, and photovoltaic parameters of MPLE-PSCs are discussed. Although the porous TiO2 layer with smaller nanoparticles showed higher photoabsorption, it was found that the more voids of perovskite crystals created in the TiO2 porous layer, the smaller the particle size (<18 nm). The porous TiO2 layers with particles over 26 nm are well filled with perovskite crystals, resulting in a higher photovoltaic capacity with TiO2 particles over 26 nm. As a result, the short-circuit current density (JSC) showed a maximum value using 43 nm TiO2 particles, with an average power conversion efficiency (PCE) of 10.56 ± 1.42%. Moreover, the PCE showed a maximum value of 12.20% by using 26 nm TiO2 nanoparticles.

Enhanced photogenic self-cleaning of superhydrophilic Al2O3@GO-TiO2 ceramic membranes for efficient separation of oil-in-water emulsions

In the emulsion separation process, the adhesion of oil-contamination severely hampers the long-term operation of ceramic membranes, and photocatalytic membranes present a promising approach to mitigate membrane fouling and enhance membrane performance. The present study describes the fabrication of a novel Al2O3@GO-TiO2 composite photocatalytic membrane through a two-step dip-coating method. TiO2 particles were uniformly deposited onto the surface of the pristine membrane via a thermal coating method, while the pleated graphene oxide (GO) formed a laminar-flow-like coating through stirring-ultrasonication, ultimately being stably anchored to the composite membrane's surface by co-built connections with TiO2. Due to the successful coating of hydrophilic groups, the composite membrane exhibited super hydrophilic-underwater superoleophobic properties to separate stable water-in-diesel emulsions with excellent permeation flux (4347.17 L∙m−2∙h−1) and oil removal rate (94.98 %). The composite membrane showed excellent oil resistance stability and durability in severe environment hydrodynamic washout and cycling tests. In addition, the combined modification of GO-TiO2 endowed the composite membranes with strong photocatalytic ability, which made the membranes exhibit a good recovery of membrane performance in the separation of oilfield-produced water (OPW). The thick oil layer was completely removed by •OH, •O2– and 1O2 generated by UV irradiation excitation. After 6 h of operation, the flux and oil removal rate of the Al2O3@GO-TiO2 membrane were 31.91 % and 2.1 % higher than those of the Al2O3@TiO2 membrane, demonstrating enhanced light self-cleaning performance. The exceptional oil–water separation capability coupled with its efficient photocatalytic degradation potential positions the ceramic membrane as a promising solution for treating actual OPW.

Experimental Study on Mechanical Characteristics of Aluminium Metal Matrix Composite Reinforced with Titanium Oxide (TiO2) and Graphite (Gr) Particles Processed by Stir Casting Method

Abstract: In recent trend Aluminium based metal matrix composites are most used in mechanical and automobile component design applications because of their excellent mechanical, Tribological and its physical properties. Also, Aluminium metal matrix composites are used for a variety of applications such as military, aerospace, electrical industries, and automotive purposes. The present work concentrates on the experimental study on the effects of TiO2 and Gr on aluminium alloy. During this investigation, Titanium oxide (TiO2) and Graphite (Gr) particles was reinforced with aluminium and it was prepared using stir casting technique with various weight percentage combinations of TiO2 particles 2% by wt., 4% by wt., and 6% by wt. and 3% of Gr constant for all trials. Mechanical parameters were estimated by selecting the standard test methods.

Physiological and agronomical traits effects of titanium dioxide nanoparticles in seedlings of Solanum lycopersicum L

BackgroundTitanium dioxide nanoparticles (TiO2 NPs) have been reported to have contrasting effects on plant physiology, while their effects on sugar, protein, and amino acid metabolism are poorly understood. In this work, we evaluated the effects of TiO2 NPs on physiological and agronomical traits of tomato (Solanum lycopersicum L.) seedlings. Tomato seeds were treated with TiO2 NPs (1000 and 2000 mg L− 1), TiO2 microparticles (µPs, 2000 mg L− 1) as the size control, and ultrapure water as negative control.ResultsThe dry matter of stems (DMs), leaves (DMl) and total dry matter (DMt) decreased as particle concentration increased. This trend was also observed in the maximum quantum yield of light-adapted photosystem II (PSII) (Fv´/Fm´), the effective quantum yield of PSII (ΦPSII), and net photosynthesis (Pn). The concentrations of sugars, total soluble proteins, and total free amino acids were unaffected, but there were differences in the daily dynamics of these compounds among the treatments.ConclusionOur results suggest that treating tomato seeds with TiO2 might affect PSII performance, net photosynthesis and decrease biomass production, associated with a concentration- and size-related effect of TiO2 particles.

Evaluation of weathering resistance of cross-laminated timber blocks surface-treated with TiO2 nanoparticles by liquid-precursor flame spray pyrolysis

Wood is a versatile and renewable resource utilized in a wide range of applications, including tools, furniture, construction, and advanced engineering structures. However, certain inherent properties of wood, such as moisture and ultraviolet (UV) degradation, impose limitations on its long-term durability and dimensional stability for outdoor applications. This research investigates the weathering durability of cross-laminated timber (CLT) blocks surface-treated with titanium dioxide (TiO2) nanoparticles synthesized via liquid-precursor flame spray pyrolysis (FSP), directly deposited onto the surface of CLT blocks, and thereby resulting in a porous TiO2 coating. This coating endows the CLT surface with superhydrophobic properties evidenced by a water contact angle of ≥150°. Results from scanning electron microscopy and X-ray diffraction show the coating to be comprised of crystalline, sub-100 nm individual and aggregated TiO2 particles with significant porosity. Even after an 8-week accelerated weathering test, a portion of the crystalline TiO2 particles remains on the CLT surface. The TiO2-treated CLT demonstrates enhanced resistance to discoloration and gloss change over 8-weeks of accelerated weathering conditions, which are evidenced by a total color difference (ΔE) that is 3–4 times lower than that of the untreated CLT in the initial two weeks, and 58% lower after 8 weeks of weathering. Furthermore, the TiO2-treated CLT exhibits fewer weathering defects, such as splits and cracks, than the untreated CLT. The enhanced weathering durability of the TiO2-treated CLT is attributed to reduced lignin degradation, which is supported by the Fourier-transform infrared spectroscopy analysis. The findings of this study suggest that the TiO2 coating by FSP offers a viable and cost-effective method for modifying engineered wood products for improving hydrophobicity and protecting against the deteriorating effects of UV irradiation and moisture exposure.

Tribological behavior of detonation sprayed CrFeNiAl0.3Ti0.3 high entropy alloy coatings in seawater environment

In this study, the CrFeNiAl0.3Ti0.3 high entropy alloy coating was deposited onto a SUS304 substrate steel by detonation spraying. The CrFeNiAl0.3Ti0.3 coating consists of FCC, BCC and B2 phases. It’s hardness, bonding strength and porosity are 576 HV, 86 MPa and 0.87%, respectively. In seawater, the tribological properties of the coating depends on the counterparts. The CrFeNiAl0.3Ti0.3/SiC sliding-pairs presents the best tribological properties in seawater due to the lubricious SiO2·nH2O and a dense tribo-layer. For AISI 440 C and Al2O3 counterparts, moderate abrasive wear occurs for the coating. For CuZn40 alloy counterpart, a soft copper-rich tribo-layer reduces the wear. For Ti6Al4V counterpart, many hard TiO2 and Al2O3 abrasion particles lead to the severe wear of the two contacting surfaces.

Control of Dielectric Parameters of Micro- and Nanomodified Epoxy Resin Using Electrophoresis

This work presents the results of research on submicro- and nanocomposites with gradient properties, produced in a planned electrophoretic process. Epoxy-resin-based samples were filled with TiO2 particles of three different sizes (13 nm, 38 nm, and <1 µm) at four different values of average electric field Eav (0.0 Vmm−1, 125 Vmm−1, 250 Vmm−1, and 500 Vmm−1) for 1 h each. Changes in selected dielectric parameters (dielectric constant εr and dielectric loss factor tanδ) of the composites were analyzed using broadband dielectric spectroscopy (10−1 Hz to 105 Hz). The influence of the Eav and the current i(t) flowing through the sample material and the Joule heat generated in it on the resin curing process and the final gradient of dielectric parameters were investigated. The results show that the degree of modification of the εr gradient increases with increasing Eav and is more pronounced in the case of TiO2 nanoparticles. The largest modifications in the εr and tanδ were obtained for nanoparticles with a diameter of 13 nm at Eav = 500 Vmm−1, while the lowest for particles < 1 µm at Eav = 125 Vmm−1. The effect of electrophoresis on the dielectric parameters is significant, especially near the anode region. Increasing the concentration of TiO2 particles at the anode occurs at the expense of reducing their concentration in the remaining volume of the sample. The test results clearly demonstrate the importance of particle dimension and electric field strength for the gradient modification of the properties of the epoxy composite using electrophoresis. Numerical simulations of electric field stresses in the epoxy resin during the electrophoresis process, performed in the COMSOL program, revealed a significant increase in the E field strength in the areas close to the anode and cathode.

Phenol degradation on the surface of mesoporous TiO2 particles via ligand-to-metal charge transfer under visible light irradiation

Degradation behaviors of phenol from aqueous solution under the blue light irradiation were studied using a series of sol–gel prepared TiO2 particles exhibiting different blue light absorbing abilities. The phenol degradation under the blue light irradiation was most pronounced in the presence of TiO2 sample exhibiting the lowest blue light absorbing ability among the samples, showing no correlations between phenol degradation and light absorbing ability of TiO2 particles. UV-DRS analysis and scavenging experiments revealed that phenol degradation under visible light irradiation can be majorly proceed via the light absorption by the ligand-to-metal-charge-transfer (LMCT).

Artificial Hydrophilic Organic and Dendrite-Suppressed Inorganic Hybrid Solid Electrolyte Interface Layer for Highly Stable Zinc Anodes.

Aqueous zinc-ion batteries (AZIBs) have gained significant attentions for their inherent safety and cost-effectiveness. However, challenges, such as dendrite growth and anodic corrosion at the Zn anode, hinder their commercial viability. In this paper, an organic-inorganic coating layer (Nafion-TiO2) was introduced to protect the Zn anode and electrolyte interface. Briefly, Nafion effectively shields against the corrosion from water molecules through the hydrophobic wall of -CF3 and guided zinc deposition from the -SO3 functional group, while TiO2 particles with a higher Young's modulus (151 GPa vs 120 GPa from Zn metal) suppress the zinc dendrite formation. As a result, with the protection of Nafion-TiO2, the symmetrical Zn∥Zn battery shows an improved cycle life of 1,750 h at 0.5 mA cm-2, and the full cell based on Zn∥MnO2 shows a long cycle life over 1,500 cycles at 1 A g-1. Our research offers a novel approach for protecting zinc metal anodes, potentially applicable to other metal anodes such as those in lithium and sodium batteries.

Fabrication and characterization of Ni-TiO2 and Ni-V2O5 single-layer and double-layer coatings with the approach of improving the wear and corrosion properties

The main purpose of this study is to investigate the metallurgical behavior of Ni-TiO2 and Ni-V2O5 single-layer coatings and compare them with Ni-TiO2/Ni-V2O5 and Ni-V2O5/Ni-TiO2 double-layer coatings. The general attitude is the optimal choice of coatings in terms of wear and corrosion properties. The dimensions of TiO2 and V2O5 ceramic powders were 20 nm and 500 nm, respectively, and their morphology was also different. The presence of the submicron V2O5 particles was more than the TiO2 nanoparticles in the nickel matrix deposit. Also, with double layering the coatings (Ni-TiO2/Ni-V2O5 and Ni-V2O5/Ni-TiO2), the presence of ceramic particles in the upper layer had increased compared to the same single-layer coatings. Therefore, the increase in the hardness of the deposits was directly related to the percentage of ceramic powders in the coating. The surface morphology of the Ni-TiO2 layers was formed as a cauliflower shape while the Ni-V2O5 deposits had a smooth morphology. Increasing participation of TiO2 particles in the Ni-TiO2 layer had made the morphology rougher. Also, by applying the Ni-TiO2 layer under the Ni-V2O5 deposit, the surface morphology of the Ni-V2O5 layer became smooth, which can be due to the increase in the V2O5 content in this layer. The lowest amount of fluctuation appeared in the roughness profiles related to the Ni-V2O5 layers, and the large fluctuation range in the Ni-TiO2 layers was due to the smooth and cauliflower structure, respectively. The crystallite size in double-layer coatings was smaller than the single-layer coatings due to the higher nucleation and growth rate of nickel deposition in the nickel matrix upper layers. According to the presented results, the Ni-V2O5 and Ni-V2O5/Ni-TiO2 coatings were the most wear resistant coatings. Also, the Ni-V2O5/Ni-TiO2 and Ni-TiO2/Ni-V2O5 double-layer coatings were suitable candidates for corrosion resistance and to consider both properties, Ni-V2O5/Ni-TiO2 was very suitable. Hardness, surface morphology, roughness, preferred planar texture, and ceramics powder participation were important parameters in determining the wear and corrosion properties of coatings. Also, it seems that the effect of the double layering of nickel matrix deposits on the metallurgical properties was greater than the dimensions of the ceramic particles participating in the coating.

High-concentration TiO2 suspension (>70 wt%) with low viscosity suitable for waterborne coatings

High-concentration TiO2 suspension is favored by industry since it would effectively simplify the processing of coatings, benefiting energy and cost savings. However, achieving a dense TiO2 suspension with low viscosity and good dispersion remains a challenge due to the large particle size and high density of pigment-grade TiO2 particles (200–400 nm). In this work, we proposed high-concentration TiO2 suspensions with low viscosity and excellent storage stability by grafting copolymer nanospheres to TiO2. The TiO2 particles are isolated through the steric hindrance and electrostatic repulsion of PMS (P(MMA-MPS)) nanospheres which are synthesized by emulsion polymerization of methyl methacrylate (MMA) and γ-methacryloxypropyltrimethoxysilane (MPS). The TiO2 suspension modified by PMS of 90 nm exhibits the highest concentration in water (74 wt%) while maintaining the lowest viscosity (95 mPa·s at the shear rate of 200 r/s). Through thermal storage at 50 °C in 28 d, the concentrated TiO2-PMS suspensions demonstrated excellent stability without any noticeable decline in coating properties compared to pure TiO2. The coating film of TiO2-PMS-90 suspension exhibited the optimal contrast ratio (92.4 %) and gloss value (78.5 GU) after thermal storage. The 50 L macro production results of TiO2-PMS-90 coincided with the lab results which will favor larger scale-up production. This work presents a strategy to enhance the dispersion stability of TiO2 particles to obtain a high-concentration slurry with low viscosity and superior flowability, particularly suitable for waterborne coatings.