Characterization Of Composites Research Articles

Photodegradation of Phenol under Visible Light Irradiation Using Cu-N-codoped ZrTiO<sub>4</sub> Composite as a High-Performance Photocatalyst

Codoping of nitrogen and copper into zirconium titanate composite (Cu-N-codoped ZrTiO4) was carried out through a sol-gel process. This study aimed to investigate the effect of copper and nitrogen dopants on the photocatalytic activity of ZrTiO4 composite in degrading phenol. To prepare the composite, an aqueous suspension of zirconia (ZrO2) alongside a fixed amount of urea and various amount of copper sulfate was added dropwise into diluted titanium(IV) tetraisopropoxide (TTIP) in ethanol. The composites were calcined at temperatures of 500, 700, and 900 °C. Fourier-transform infrared spectrophotometry (FTIR), X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray (SEM-EDX) mapping, and specular reflectance UV-visible spectrophotometry (SR UV-vis) were used for their characterization of composite. The photocatalytic activity was evaluated by adding the composite into a 10 mg L−1 phenol solution for various irradiation time spans. The remaining concentration of phenol solution was determined by absorption at 269 nm. Cu-N-codoped ZrTiO4 composite containing 5% Cu calcined at 500 °C demonstrated the highest observed rate constant and a significant band gap decrease from 3.13 to 2.68 eV.

Characterization and fractography of stir-cast ZA-27 composites reinforced with Zircon silicate and MoS2 solid lubricant particles

Zinc Aluminum alloy (ZA-27) is a primarily known alloy used in bearings. In this work the alloy is reinforced with Zircon silicate in varying amounts ranging from 1.5 wt% to 6 wt%, incrementally increasing by 1.5 wt%, along with 3 wt% Molybdenum di sulfide (MoS2) microparticles via a stir-casting process. Zircon silicate is prized for its increased hardness and thermal stability, and MoS2 provides remarkable wear resistance to the composite. The primary goal of this study is to investigate how Zircon silicate particles and MoS2 affect the strength and fracture behavior of the prepared composites. The current study shows a decrease in both load bearing and percentage elongation as the Zircon silicate concentration increases, owing to weaker MoS2 secondary particles inside the ZA-27 matrix. To provide a suitable explanation for crack development, the study also includes microstructure analysis, evaluation of porosity, microhardness, CTE evaluation, and the influence on the fracture mechanism of the ZA-27 composites.

Development and characterization of smart composites reinforced with fibrillated cellulose and nickel-titanium alloy

The current study presents the synergistic effects of fibrillated cellulose (FC) and nickel-titanium (NiTi) alloy on the performance properties of smart composites. Epoxy resin was reinforced with loadings of 1 %, 3 %, and 5 % FC and 3 % NiTi. The composites were produced using the casting method. The morphological properties have been analyzed using scanning electron microscopy (SEM). For mechanical properties, yield strength, modulus of elasticity, hardness, and impact energy were determined. The corrosion rate was determined via electrochemical corrosion testing. The recovery test was used to measure the shape-memory of the composites. The self-healing of the artificial defect in the composites was observed using a thermal camera. The yield strength, modulus of elasticity, hardness, and impact energy of composites reinforced with 5 % FC and 3 % NiTi increased by 168.2 %, 290 %, 33.3 %, and 114.3 %, respectively, compared to pure epoxy resin. There has been a 56.3 % decrease in the corrosion rate. The percentage of composites that returned from the final state to the original state after a deformation was 4 %. Self-healing analysis revealed that the scratch defect in composites was healed after 24 h. It is concluded that smart composites can be used in the aviation and automotive industries.

Effect of the Printing Angle on the Microstructure and Tensile Performance of Iron-Reinforced Polylactic Acid Composite Manufactured Using Fused Filament Fabrication

This work emphasizes an innovative approach utilizing 3D imaging technology based on synchrotron radiation to assess the microstructure of second-phase iron particles and the porous structure within 3D-printed PLA/magnetic iron composites at different printing angles. The study examines how these observations relate to the material’s ductility when processed using fused filament fabrication. In particular, this study examines the impact of one processing parameter, specifically the printing angle, on the microstructure and mechanical behaviour of a polylactic acid (PLA)–iron (PLI) composite designed for magnetic actuation. Fused filament fabrication is employed to produce PLI tensile specimens, with varied printing angles to create different layups. X-ray microtomography is utilized to analyse the microstructure, while tensile mechanical properties are evaluated for all composites, with findings discussed in relation to printing angle conditions. Scanning Electron Microscopy is used to examine the fractography of broken specimens. Results indicate that the printing angle significantly influences the tensile properties and mechanical anisotropy of 3D-printed PLI composites, with an optimal 45°/45° layup enhancing tensile performance. These findings suggest that 3D-printed PLI composites offer a cost-efficient means of producing bio-sourced, light-adaptive materials with intricate magnetic actuation capabilities. By quantifying the modulation of mechanical properties based on printing parameters that influence microstructural arrangement, the research sheds light on a novel aspect of composite material characterization.

Valorization of spent Zn-C battery and construction and demolition waste (CDW): Fabrication and characterization of geopolymer composites for radiation shielding applications

There is a serious threat of pollution due to the high waste of energy and materials worldwide that needs to be decreased. One way is to reduce waste or use them in secondary processes. New eco-friendly geopolymer binders were fabricated using metakaolin, CDW, and battery waste (BW) powders as starting materials and a mixture of potassium silicate and sodium hydroxide as activation solutions. 5 formulations with BW powder replacements ranging from 5 to 40 wt% were prepared and subjected to heat curing at 80 °C for 24 h. The effect of Zn-C battery waste content on the phase composition, densification, microstructure, mechanical, and gamma shielding properties of the obtained geopolymer composites was investigated. The results revealed that incorporating battery waste reduced the density and mechanical strength of the geopolymer composites. Additionally, microstructural analysis indicated that synthesized geopolymers consisted of unreacted CDW and BW particles embedded in a geopolymer matrix with a low degree of compactness. The effect of BW replacement on the shielding capacity was also evaluated experimentally and theoretically. The gamma transmission experiments proved that the addition of BW caused a reduction in the radiation shielding ability of the composites when they were exposed to 137Cs and 60Co gamma-ray sources. Finally, the variation of the main attenuation parameters (MAC, HVL, EBF, and EABF) with photon energy was also obtained theoretically. The outcomes of this investigation can provide a basis for the design of new CDW-based geopolymers for radiation shielding applications in the context of a circular economy.

Fabrication of Tungsten Oxide Nanowalls through HFCVD for Improved Electrochemical Detection of Methylamine.

In this study, well-defined tungsten oxide (WO3) nanowall (NW) thin films were synthesized via a controlled hot filament chemical vapor deposition (HFCVD) technique and applied for electrochemical detection of methylamine toxic substances. Herein, for the thin-film growth by HFCVD, the temperature of tungsten (W) wire was held constant at ~1450 °C and gasification was performed by heating of W wire using varied substrate temperatures ranging from 350 °C to 450 °C. At an optimized growth temperature of 400 °C, well-defined and extremely dense WO3 nanowall-like structures were developed on a Si substrate. Structural, crystallographic, and compositional characterizations confirmed that the deposited WO3 thin films possessed monoclinic crystal structures of high crystal quality. For electrochemical sensing applications, WO3 NW thin film was used as an electrode, and cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were measured with a wide concentration range of 20 μM~1 mM of methylamine. The fabricated electrochemical sensor achieved a sensitivity of ~183.65 μA mM-1 cm-2, a limit of detection (LOD) of ~20 μM and a quick response time of 10 s. Thus, the fabricated electrochemical sensor exhibited promising detection of methylamine with considerable stability and reproducibility.

Ultrasound-Driven Deposition of Au and Ag Nanoparticles on Citrus Pectin: Preparation and Characterisation of Antimicrobial Composites.

Pectin is a renewable, non-toxic and biodegradable polymer made of galacturonic acid units. Its polar groups make it suitable for complexing and supporting metallic nanoparticles (NPs). This work aimed to produce antibacterial nanocomposites using pectin and acoustic cavitation. The metal NPs (Au or Ag) were deposited using ultrasound (US, 21 kHz, 50 W) and compared with those achieved with mechanical stirring. The impact of the reducing agents (NaBH4, ascorbic acid) on the dispersion and morphology of the resulting NPs was also assessed. Characterization by diffuse reflectance (DR) UV-Vis-NIR spectroscopy and field emission scanning electron microscopy (FESEM) showed that the use of US improves the dispersion and decreases the size of both Au and Ag NPs. Moreover, with Au NPs, avoiding external reductants led to smaller NPs and more uniform in size. The prepared NPs were functionalized with oxytetracycline in water and tested against Escherichia coli (gram negative) and Staphylococcus epidermidis (gram positive) via the Kirby-Bauer test. The results show a better antibacterial activity of the functionalized nanoparticles compared to antibiotic-free NPs and pure oxytetracycline, advising the potential of the nanoparticles as drug carriers. These findings underscore the significance of US-assisted synthesis, paving the way to new environmentally friendly antimicrobial materials.

Superior tribological and sealing performance of micro-crystalline diamond coated silicon carbide seals under dry friction and high load

Silicon carbide seals suffer severe wear under the conditions of dry friction and high load, posing a great challenge in achieving a stable performance and a long lifetime. In this work, micro-crystalline diamond coatings were deposited on silicon carbide sealing rings to prevent the failure caused by wear. The deposited micro-crystalline diamond coatings exhibit high-quality crystallinity and strong adhesive strength with the silicon carbide substrate. In sealing tests, the micro-crystalline diamond coated silicon carbide sealing pair demonstrates superior tribological and sealing properties under dry friction and high load of 1800 N, featuring a low coefficient of friction of 0.16, a low wear rate of 4.00 × 10−7 mm3·N−1·m−1 and a high friction limit of 5.24 MPa·m·s−1. Characterizations of morphology, chemical composition and microstructure confirm that the smoothening effect on the contact face and the formation of graphite during the sealing test synergistically contribute to the outstanding tribological and sealing performance.

Demonstration of computer vision for void characterisation of 3D-printed continuous carbon fibre composites

Microstructural void formation during the processing of continuous fibre-reinforced polymer composites are a significant limitation of processes such as 3D printing, as voids inhibit resultant mechanical properties. Traditional optical microscopy approaches to void characterisation are tedious and are prone to errors due to non-ideal but realistic image conditions, including low contrast typical of microscopic images. This paper proposes a novel application of automated computer vision image processing techniques (i.e. a contrast-limited adaptive histogram equalisation (CLAHE) algorithm and Otsu's method) for detailed void characterisation of continuous fibre-reinforced composites. Microstructural void fraction was determined for both unidirectional and bi-axial laminates of a variety of thicknesses. The void characterisation by computer vision was shown to produce comparable results with manual contrast/brightness control, but with significantly less standard deviation. The computer vision software used in void characterisation is made freely available online at https://github.com/Xiao-ying/VoidDetector.

Potential of recycled polypropylene: A study on effect of natural fiber on the morphology and properties of biocomposite

This research explores the innovative fabrication and characterization of recycled polypropylene composites that reinforced by natural fibers, specifically date palm micro fibers (DPF). Employed a twin-screw extruder for the mixing, and injection molding technique for the samples fabrication. DPF was incorporated at varying weight percentages (0, 2, 5, and 10 wt%). A comprehensive analysis, including thermal gravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), was conducted to assess thermal stability, chemical interactions and crystalline structure. Mechanical properties were evaluated through shore-D hardness and uniaxial tensile tests. Notably, the study revealed that an increased DPF filler content resulted in superior mechanical properties, such as enhanced shore-D hardness and tensile strength. This improvement was attributed to the alignment of DPF fillers and the recycled polypropylene matrix. The significance of this research lies in showcasing the promising potential of DPF as an eco-friendly reinforcement material in recycled polypropylene biocomposites, providing a sustainable and environmentally friendly alternative for various engineering applications. The work contributes to advancing greener solutions in material science and highlights the unique advantages of DPF in enhancing composite materials.

Comparative analysis of machine learning models for predicting dielectric properties in MoS2 nanofiller-reinforced epoxy composites

This research investigates the dielectric properties of nano epoxy composites by incorporating various concentrations of MoS2 into epoxy resin. The study explores the impact of synthesized nanoparticles on undoped epoxy composites, specifically focusing on their potential applications in dielectric materials. The experimental synthesis and characterization of nanoepoxy composites typically involve time-consuming and expensive methods. This study compares five machine learning (ML) models—random forests, decision trees, extra trees, XGBoost, and gradient boosting—in order to predict the frequency-dependent dielectric constants in these composites under different nanofiller variations in order to address this challenge. To ensure robust model performance, training is carried out on different subsets of the dataset, ranging from 60% to 30%, while the remaining portions are reserved for testing purposes (40% to 70%). The main objective of the study is to assess the performance of each regressor technique using metrics such as adjusted R2 score, MSE, RMSE, and MAE, in which the ET regressor excels. The ET method demonstrates exceptional performance, achieving an adjusted R2 value of 0.9977 and 0.9912 for target variables ε′ and ε′′, respectively when tested with a size of 0.4. The findings underscore the potential of ML models for precise and efficient prediction of frequency-dependent dielectric constants of nanoepoxy composites with various concentrations of nanofillers, offering an alternative to time-consuming and expensive laboratory work.

Toward waste glass upcycling: Preparation and characterization of high-volume waste glass geopolymer composites

Portland cement-free high-volume waste glass geopolymer composite is proposed for the upcycling of glass waste. The “high-volume” is achieved by utilizing GP as the geopolymer precursor and glass cullet as the aggregate. Our observations show decent strength and durability can be obtained by the composites with up to ∼83 wt% waste glass by the mass of solid components. GP and common geopolymer precursors (class C and class F fly ash and slag) have synergistic effects on forming calcium-(sodium-)aluminosilicate hydrate (C-(N-)A-S-H) and sodium-aluminosilicate hydrate (N-A-S-H). A higher Ca content and dosage of Na2O, however, lead to a larger drying shrinkage. Although glass aggregate can reduce the shrinkage to some extent, the highly reactive aggregate may cause the progressive ASR in the Ca-rich mixtures. The ASR expansion decreases with the increasing dosage of Na2O possibly because an overly high pH in pore solution thermodynamically hindered the precipitation of ASR gels and/or a higher alkaline concentration favors the dissolution of aggregate surfaces at curing stage, and the dissolved Si participates in the hydration process.

Surface Composites Synthesized through the Incorporation of Atomic Layer Deposited AlOx into Nanoporous Fuzzy Tungsten.

The incorporation of energetic helium gaseous species into materials such as tungsten (W) imparts intrinsic surface fragility, yielding fuzzy tungsten. To enhance the robustness of the surface layers, aluminum oxide (AlOx) was deposited by atomic layer deposition into the fuzzy W. The conformally deposited ceramic yields a new class of surface composites. Structural characterization of the fuzzy W-AlOx composites through nanoindentation testing indicated enhanced indentation modulus (Eind) and hardness (Hind) and was modeled through various rules of mixtures approaches. The distribution of AlOx in fuzzy W was explored and a systematic study of the extent of incorporation of the AlOx into the fuzzy W was carried out. The synthesized composites may be utilized for improved structural characteristics, e.g., in reducing crack initiation and fracture.

Effect of jute stick charcoal powder on characterization of aluminum metal matrix composite

The present work indicates the fabrication of Aluminum Metal Matrix Composites (MMCs) reinforced jute stick charcoal powder (JSCP) using stir casting process and investigates different properties of fabricated composites. Mechanical properties such as flexural strength, tensile strength, hardness, and impact tests are investigated. Additionally, the morphology of the MMCs were analyzed using scanning electron microscopy (SEM). Furthermore, X-ray diffraction (XRD) analysis was used to identify the phase of the MMCs. From the investigation it was found that the tensile and flexural strength of the Al+3% JSCP composite decreased by 27.1% and 1.32% respectively compared to the Al+1% JSCP composite. On the other hand, impact strength and hardness were slightly greater for Al+3% JSCP composite. SEM analysis revealed micro-cavities and charcoal powder particle size and distribution differences. XRD patterns of the prepared composite revealed the presence of JSCP and lattice parameter of the composite. The investigation of surface roughness under different cutting speed reveals that, composite with 1% JSCP exhibited a higher surface roughness than the composite with 3% JSCP because the micro-cavity and porosity was less in Al+3% JSCP.

Preparation and characterization of biomass-ash composites derived from incinerated sewage sludge fly ash after hydrothermal treatment

With the increasing prominence of global environmental issues and the growing demand for sustainable development, biomass composites have attracted widespread attention as candidates for environmentally friendly and renewable construction materials. In this study, environmentally friendly biomass-ash composites (BACs) were fabricated using hydrothermally activated incinerated sewage sludge ash (HT-ISSA) as filler and straw powder with waste sawdust as the biomass matrix for hot pressing. An investigation was conducted into the effect of HT-ISSA on the physical properties of the composite, including the bending strength, compressive strength, and thermal conductivity. The composite prepared with 15 wt% HT-ISSA demonstrated an exceptionally high bending strength (30.60 MPa), compressive strength (44.76 MPa), and low thermal conductivity (0.2380 W/m·K). The enhanced physical properties of the BAC material are attributable to the change caused by hydrothermal treatment of the filler phase. Due to the introduction of hydrated calcium silicate, the cohesion performance of the filler significantly improved, thus leading to strong adhesion and penetration within the matrix. The obtained BAC is applicable for packaging and insulation materials, thus providing an effective solution for the economical and environmentally friendly recycling of incinerated sewage sludge ash and other bulk solid waste. Additionally, it contributes novel insights into alleviating the current shortage of forest resources.

Carbon black silicone composite in surgical simulation—A detailed electromechanical characterization

The integration of advanced materials into surgical simulators has revolutionized medical training. In this study, a detailed characterization of carbon black silicone composites specifically designed as soft sensor material in hybrid surgical simulators including a hyper visco plasto elastic model is performed. Carbon black-silicone composites offer unique properties such as flexibility, softness and electrical conductivity, making them ideal for integration into synthetic tissue imitations in simulators. These sensors provide real-time feedback on tissue deformation, improving the realism and evaluation capability of surgical simulations. The comprehensive, closed-form material model enables detailed analysis of the composite’s mechanical and electrical behavior, accounting for viscoelasticity, plasticity and hyperelasticity. The application of this model provides insights into the behavior of the conductive composite in different sensory scenarios, which facilitates the development of more realistic simulators.

Reducing anisotropy of rhombohedral Bi-rich phase for high-performance Ag-alloyed Sn–Bi low-temperature solders

The rhombohedral structure is with anisotropic properties, leading to brittle mechanical properties. However, it is one of the major constituent phases, the (Bi) phase, in the Sn–Bi-based low-temperature solders, which is demanding in the electronic industry for reducing the soldering temperature and alleviating the warpage in high-density fine-pitch electronic packaging. Herein, we proposed a high-performance Ag-alloyed Sn–Bi (SBA) low-temperature solder by reducing the fraction and, more importantly, the anisotropy of the (Bi) phase. We found that the (Bi) phase exhibited considerable solubility for Ag and Sn, even after thermal aging, without any nanoprecipitates as confirmed with both CALPHAD-type thermodynamic modeling and high-resolution TEM. The solution effects of Ag and Sn in the (Bi) phase is elaborated based on in situ nano-indentation, EPMA compositional analyses, EBSD characterizations, and ab initio calculations. The presence of Ag and Sn in the (Bi) phases resulted in both solid solution hardening and softening effects, depending on the Schmid factor of the grain. As a result, in (Bi) polycrystals, alloying could effectively mitigate the anisotropic mechanical properties of the (Bi) phase and facilitated a more uniform dispersion of forces exerted among (Bi) grains in all orientations. Consequently, the designed SBA solder exhibited superior mechanical properties, e.g., an ultimate tensile strength (UTS) of 55 MPa, elongation of 46%, and toughness of 20.6 × 106 J/m3 at a strain rate of 0.0005 s−1. This understanding opens the door for enhanced rhombohedral phase in alloy design for various applications.

Characteristics and Influence Factors of Pb(II) Adsorption by Graphene Oxide-Montmorillonite Composite.

This study presents the fabrication of a novel porous composite of graphene oxide-montmorillonite (GO-MMT) through the modification of montmorillonite using the freeze-drying method for the purpose of Pb removal. The characterization of the GO-MMT composite was conducted using scanning electron microscopy, Fourier transform infrared spectrometry, and X-ray diffraction. The results from batch adsorption experiments revealed that the GO-MMT composite exhibited a superior capacity for Pb removal compared to MMT. Furthermore, a single factor experiment confirmed that the dosage of the GO-MMT composite or GO, pH, temperature, and reaction time all significantly influenced the adsorption of Pb by the GO-MMT composite, MMT, or GO. This superiority can be attributed to the presence of oxygen-containing functional groups, the site-blocking effect, and the ion exchange mechanism exhibited by the GO-MMT composite.

Elastic-plastic properties of ceramic matrix composites characterization by nanoindentation testing coupled with computer modeling

The nanoindentation test is utilized to measure the hardness and elastic modulus of various components within Ceramic Matrix Composites (CMCs), including continuous stiffness measurement (CSM) and quasi-static testing. To further characterize the elastic-plastic properties of CMCs, an efficient method is proposed by using backpropagation (BP) neural network inversion, which is based on the relationship between load and depth obtained by the nanoindentation experiment and Abaqus finite element simulation. As part of the analysis, the load-depth (p-h) curve is simplified to six characteristic parameters through the fitting of the experimental results. The pre-estimated elastic-plastic characteristics are utilized to model the nanoindentation test for CMCs. A BP neural network is used to perform deep learning on simulation data, which leads to a network structure that matches the trained parameters of the p-h curve and elastic-plastic properties. The experimental data for fiber is inputted into the network to acquire the elastic-plastic properties required in practice. The accuracy of the proposed method is verified by comparing the inversion results with the simulation outcomes.

Holistic Characterization of MgO-Al2O3, MgO-CaZrO3, and Y2O3-ZrO2 Ceramic Composites for Aerospace Propulsion Systems

Aerospace propulsion systems are among the driving forces for the development of advanced ceramics with increased performance efficiency in severe operation conditions. The conducted research focused on the mechanical (Young’s and shear moduli, flexural strength, hardness, and fracture toughness), thermal (thermal conductivity and coefficient of thermal expansion), and electric (dielectric properties) characterization of MgO-Al2O3, MgO-CaZrO3, and stable YSZ ceramic composites. The experimental results, considering structural and functional traits, underscore the importance of a holistic understanding of the multifunctionality of advanced ceramics to fulfill propulsion system requirements, the limits of which have not yet been fully explored.