Metal-based Materials Research Articles

Efek gaya tekan pembuatan hibrid komposit berpenguat SiCw/Al2O3 dengan wetting agent Mg terhadap sifat fisik dan mekanik

The growing demand for metal-based materials in the manufacturing industry has prompted the development of composite materials that have better mechanical and physical properties than single materials. The development be done in order to obtain new materials that have better properties. The research was conducted using a powder metallurgy process, by varying the compressive force and holding time in order to determine the effect of the combination of compression and holding time on the mechanical and physical properties of composites. The variations in the compressive force are 20, 25, and 30 kN, with a holding time of 15, 30 and 45 minutes for each force. Research includes tests of density, porosity, hardness, wear and Scanning Electronic Microscope. The results of the density test showed that the highest density value was 2.982 gr/cm 3 and the lowest porosity value was 13.074% at a compressive force of 25 kN, holding time of 45 minutes. The results of the highest hardness value 53.455 kg/mm 2 at 30 kN, 45 minutes and the lowest wear value 2.15455E-05 gr at a pressure of 20 kN, 15 minutes. Based on the test results, the characteristics of the density are inversely proportional to the porosity, while the hardness and wear are influenced by the length of holding time in the moldof a composite using aluminum as a matrix needs too.

Novel Inorganic Nanomaterial-Based Therapy for Bone Tissue Regeneration.

Extensive bone defect repair remains a clinical challenge, since ideal implantable scaffolds require the integration of excellent biocompatibility, sufficient mechanical strength and high biological activity to support bone regeneration. The inorganic nanomaterial-based therapy is of great significance due to their excellent mechanical properties, adjustable biological interface and diversified functions. Calcium–phosphorus compounds, silica and metal-based materials are the most common categories of inorganic nanomaterials for bone defect repairing. Nano hydroxyapatites, similar to natural bone apatite minerals in terms of physiochemical and biological activities, are the most widely studied in the field of biomineralization. Nano silica could realize the bone-like hierarchical structure through biosilica mineralization process, and biomimetic silicifications could stimulate osteoblast activity for bone formation and also inhibit osteoclast differentiation. Novel metallic nanomaterials, including Ti, Mg, Zn and alloys, possess remarkable strength and stress absorption capacity, which could overcome the drawbacks of low mechanical properties of polymer-based materials and the brittleness of bioceramics. Moreover, the biodegradability, antibacterial activity and stem cell inducibility of metal nanomaterials can promote bone regeneration. In this review, the advantages of the novel inorganic nanomaterial-based therapy are summarized, laying the foundation for the development of novel bone regeneration strategies in future.

Theoretical design of Salen–metal-based materials for highly selective separation of C2H2/C2H4

C2H4 is an essential industrial organic chemical. Efficiently removing C2H2 from C2H2/C2H4 mixtures is a significant challenge. Introducing a Salen–metal unit into porous materials is a practical way to separate gas mixtures. In this work, we used density functional theory (DFT) and grand canonical Monte Carlo (GCMC) method investigated the performances of different Salen–metal complexes in separating C2H2 from C2H4. The gas adsorption energies of fourteen Salen–metal complexes were systemically studied. Two complexes, Salen–Mn (II) and Salen–Ni (II), exhibited superior adsorptive selectivity in capturing C2H2 and C2H4. This result will be helpful for developing porous materials for the efficient removal of C2H2 from C2H2/C2H4 mixtures.

Controllable hydrogen generation behavior by hydrolysis of MgH2-based materials

Hydrogen supply via the hydrolysis of light-weight metal-based materials is a promising technology for the development of portable hydrogen fuel cells. The hydrolysis reaction of MgH2 with water has been significantly activated through changing the aqueous solution. Special difficulty encountered with these experimental attempts, however, is the lack of satisfactory method to adjust the hydrogen generation rate. In this work, the catalytic activity of typical oxides, hydroxides and chlorides on the MgH2 hydrolyzed in water is systematically investigated, thereby tuning the hydrolysis reaction kinetics of MgH2. It is found that the hydrogen generation rate of the system can be improved dramatically when hydrolyzed in a slightly acidic solution of chloride salts. A mechanism called solution ion effect with consideration both of the anions and cations in the solution is proposed. Such an effect is also found to be strongly correlated to other factors such as the particle size, ion concentration. As consequence, both the hydrogen generation rate and capacity can be well-controlled by tailoring the milling time, concentration of aqueous solutions and the way of introducing solute. Our findings provide new strategies in tailoring the hydrolysis kinetics of light-weight metal hydrides.

Iron anchored microporous cobalt phosphonate novel nanostructure for efficient oxygen evolution reaction

Very recently, microporous transition metal-based organic-inorganic hybrid phosphonate nanostructured materials have attracted attention for their good potential in electrocatalytic application involving oxygen evolution reaction (OER). Newly designed Iron anchored microporous cobalt-based phosphonate materials i.e. FeCoNTMP has been synthesized utilizing nitrilotri(methylphosphonic acid) under the hydrothermal reaction condition in absence of any structure directing agent (SDA). Moreover, FeCoNTMP material exhibits excellent catalytic performance towards electrochemical oxygen evolution reaction with the low overpotential value of 289 mV at the current density of 10 mA cm−2 in 1.0 M basic solution whereas Tafel slope was 59.3 mV dec-1. In addition, FeCoNTMP catalyst displays the outstanding durability up to 25 h, suggesting the potential heterogeneous electrocatalyst.

Revealing the electrocatalytic behaviour by a novel rotating ring-disc electrode (RRDE) subtraction method: A case-study on oxygen reduction using anthraquinone sulfonate

The state-of-the-art procedure for investigating homogenous and heterogeneous electrocatalysts is cyclic voltammetry (CV). However, this technique usually requires an inactive electrode material. One common problem arising e. g. in studying the oxygen reduction reaction (ORR) is the significant background contribution to the overall ORR current provided by many carbon-based and metal-based electrode materials. Furthermore, rotating ring-disc electrodes (RRDEs) made of common materials like glassy carbon/platinum (GC/Pt) can be affected by overlapping reduction potentials on the disc. Interference from overlapping reactions on the ring might also occur, particularly in connection with oxygen reduction and hydrogen peroxide oxidation in ORR studies.We present herein a novel subtraction method which allows a semi-quantitative description of homogeneous electrocatalysts and helps to overcome the overlapping problems described above using anthraquinone-2-sulfonate (AQS) as a “case study material” for the ORR.

Design Strategies of Non-Noble Metal-Based Electrocatalysts for Two-Electron Oxygen Reduction to Hydrogen Peroxide.

Hydrogen peroxide (H2 O2 ) is a highly value-added and environmentally friendly chemical with various applications. The production of H2 O2 by electrocatalytic 2e- oxygen reduction reaction (ORR) has drawn considerable research attention, with a view to replacing the currently established anthraquinone process. Electrocatalysts with low cost, high activity, high selectivity, and superior stability are in high demand to realize precise control over electrochemical H2 O2 synthesis by 2e- ORR and the feasible commercialization of this system. This Review introduces a comprehensive overview of non-noble metal-based catalysts for electrochemical oxygen reduction to afford H2 O2 , providing an insight into catalyst design and corresponding reaction mechanisms. It starts with an in-depth discussion on the origins of 2e- /4e- selectivity towards ORR for catalysts. Recent advances in design strategies for non-noble metal-based catalysts, including carbon nanomaterials and transition metal-based materials, for electrochemical oxygen reduction to H2 O2 are then discussed, with an emphasis on the effects of electronic structure, nanostructure, and surface properties on catalytic performance. Finally, future challenges and opportunities are proposed for the further development of H2 O2 electrogeneration through 2e- ORR, from the standpoints of mechanistic studies and practical application.

Substituent position effect of Co porphyrin on oxygen electrocatalysis

Substituent effect of metal porphyrin molecular catalysts plays a crucial role in determining the catalytic activity of oxygen electrocatalysis. Herein, substituent position effect of Co porphyrins on oxygen electrocatalysis, including the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER), was investigated. Two Co porphyrins, namely 2,4,6-OMe-CoP and 3,4,5-OMe-CoP, were selected as the research objects. The ORR and OER performance was evaluated by drop-coating molecular catalysts on carbon nanotubes (CNTs). The resulted 3,4,5-OMe-CoP/CNT exhibited high bifunctional electrocatalytic activities and better long-term stability for both ORR and OER than 2,4,6-OMe-CoP/CNT. Furthermore, when applied in the Zn-air battery, 3,4,5-OMe-CoP/CNT exhibited comparable performance to that with precious metal-based materials. The enhanced catalytic activity may be attributed to the improved charge transfer rate, mass transfer and hydrophilicity. This work provides an effective strategy to further enhance catalytic activity by introducing substituent position effect, which is of great importance for developing more efficient energy-related electrocatalysts.

Strongly coupled Te-SnS2/MXene superstructure with self-autoadjustable function for fast and stable potassium ion storage

Potassium‐ion batteries (PIBs) are a promising candidate for next‐generation electric energy storage applications because of the abundance and low cost of potassium. However, the development of PIBs is limited by sluggish kinetics and huge volume expansion of anodes, leading to poor rate capability and cycling stability. Herein, an advanced superstructure anode, including Te-doped SnS2 nanosheets uniformly anchored on MXene surface (Te-SnS2/MXene), is rationally designed for the first time to boost K+ storage performance. Featuring with strong interface interaction and self-autoadjustable interlayer spacings, the Te-SnS2/MXene can efficiently accelerate electron/ion transfer, accommodate volume expansion, inhibit crack formation, and improve pseudocapacitive contribution during cycling. Thus, the novel Te-SnS2/MXene anode delivers a high reversible capacity (343.2 mAh g−1 after 50 cycles at 0.2 A g−1), outstanding rate capability (186.4 mAh g−1 at 20 A g−1), long cycle stability (165.8 mAh g−1 after 5000 cycles at 10 A g−1 with a low electrode swelling rate of only 15.4%), and reliable operation in flexible full battery. The present Te-SnS2/MXene becomes among the best transition metal-based anode materials for PIBs reported to date.

Construction, mechanism and prospective of conductive polymer composites with multiple interfaces for electromagnetic interference shielding: A review

Electromagnetic interference (EMI) shielding materials have become very important materials in modern society due to the increasing electromagnetic pollution. Although metal-based materials exhibited high shielding performance, they had lots of drawbacks, such as high density, less flexibility, low corrosion resistance, costly processing, and high surface reflection. Conductive polymer composites (CPC) gradually have come to the fore in recent years because the shortages of metal-based materials could overcome by CPC. However, the high-performance EMI shielding usually required high content of conductive fillers in CPC, which leaded to new drawbacks, such as mechanical deterioration, cost increase, and processing difficulties. Therefore, the main challenge for EMI shielding CPC was to achieve high EMI shielding effectiveness (SE) at low content of conductive fillers. In this paper, the CPC with multiple interfaces which has demonstrated to improve EMI SE was reviewed. First of all, the theory of EMI shielding in CPC was introduced in detail. Second, the CPC with various multiple structures, including foamed/porous, segregated, multi-component, multilayered/sandwiched, and prefabricated conductive networks, was discussed. Third, the reported mechanism of CPC with multiple interfaces was given in this paper.

Development and current situation of flexible and transparent EM shielding materials

The application of electromagnetic (EM) technology has greatly promoted the progress and development of society, and also brought the side effects of EM interference (EMI). In the fields of visualization windows, transparent wearable devices, and aerospace equipment, flexibility and transparency have become the performance requirements of EMI shielding materials. Materials such as metal-based materials, MXenes, carbon-based materials, and conductive polymers show the potential for flexibility and transparency and lots of cases have been developed. This article summarizes the flexible and transparent properties of mainstream EMI shielding materials, and evaluates their potential as flexible and transparent EMI shielding materials. Finally, the research progress of flexible and transparent EMI shielding materials based on different advanced technologies is summarized.

A Review of Water-Resistant Cellulose-Based Materials in Pharmaceutical and Biomedical Application.

Cellulose, having huge reserves of natural polymers, has been widely applied in pharmaceutical and biomedicine fields due to its good biocompatibility, biodegradability, non-toxicity and excellent mechanical properties. At present, water- resistant metal-based and petroleum-based materials applied in the medical field have obvious problems of poor biocompatibility and high cost. Therefore, water-resistant cellulose- based materials with good biocompatibility and low price have become an attractive alternative. This review aims to summarize the preparation of water-resistant cellulose- based materials and their potential application in pharmaceutical and biomedical in recent years. Common hydrophobic treatments of cellulose fibers or paper were overviewed. The preparation, properties and applications of water-resistant cellulose- based materials in the pharmaceutical and biomedical fields were summarized. Common hydrophobic treatments of cellulose fibers or paper were divided into chemical modification (graft polymerization, crosslinking, solution casting or dip-coating), physico-chemical surface modifications (plasma treatments, surface patterning, electrostatic spraying and electrowetting) and physical processing (electrostatic spinning, SAS process and 3D EHD printing). These hydrophobically processed cellulose fibers or paper could be prepared into various water-resistant cellulose-based materials and applied in pharmaceutical excipients, drug-loaded amphiphilic micelles, drug-loaded composite fibers, hydrophobic biocomposite film/coatings and paper-based detectors. They presented excellent water resistance and biocompatibility, low cytotoxicity and high drug loading ability, and stable drug release rate, etc., which could be used for water-insoluble drugs carriers, wound dressings, and medical testing equipment. Currently, water-resistant cellulose-based materials were mainly applied in water-insoluble drugs delivery carriers, wound dressing and medical diagnosis and presented great application prospects. However, the contradiction between hydrophobicity and mechanical properties of these reported water-resistant cellulose-based materials limited their wider application in biomedicine such as tissue engineering. In the future, attention will be focused on the higher hydrophobicity of water-resistant cellulose-based materials with excellent mechanical properties. In addition, clinical medical research of water-resistant cellulose-based materials should be strengthened.

Recent Advances in Organocatalytic Ring-opening Polymerization

As compared with widely used polyolefin materials, aliphatic polyesters have been primarily used in electronics, packaging, and biomedicine owing to its unique biocompatibility and degradability. At present, ring-opening polymerization (ROP) of lactone is the main method to synthesize polyesters. Two types of catalysts, including metal-based catalysts and organocatalysts, were most researched today. However, metal-based catalysts lead to polymer materials with metal residues, which limits its properties and applications. As a result, organocatalysts have received great attention. In this review, the progress of organocatalytic ring-opening polymerization in the past decades was systematically summarized. The potential challenges and development directions in this field are also discussed.

Realization of 3D epoxy resin/Ti3C2T x MXene aerogel composites for low-voltage electrothermal heating

Suitable electrothermal materials with high heating rates at low electric power are highly desirable for de-icing and thermal management applications. Herein, 3D epoxy resin/Ti3C2T x MXene composites are synthesised and shown to be promising candidates for electrothermal heaters where the MXene serves as a nanoheater and the epoxy resin spreads the heat. A unidirectional freeze-casting technique was used to prepare an anisotropic Ti3C2T x aerogel into which epoxy resin was then vacuum infiltrated and cured. The resulting composite showed an excellent Joule heating performance over repeated heating–cooling cycles. A steady-state temperature of 123 °C was obtained by applying a low voltage of 2 V with 5.1 A current, giving a total power output of 6.1 W cm−2. Such epoxy/MXene aerogel composites, prepared by a simple and cost-effective manner, offer a potential alternative to the traditional metal-based and nanocarbon-based electrothermal materials.

Promotional effect of embedded Ni NPs in alginate-based carbon toward Pd NPs efficiency for high-concentration p-nitrophenol reduction

Noble metal-based catalytic material with maximum utilization is of prime attraction for conserving rare metal resources. Herein, highly dispersion Ni nanoparticles (NPs)-modified N-doped mesoporous carbon material (Ni-N@C) was fabricated by pyrolysis of Ni2+/Histidine cross-linked alginate hydrogels. In a step forward, the obtained Ni-N@C nanocatalyst was treated by the solution of Pd2+, and tiny amount of Pd NPs were deposited on the surface of Ni via the reducibility of Ni to achieve the high dispersion of precious metals material. In the degradation of highly-concentration p-nitrophenol, the catalyst presents excellent performance which could completely degrade pollutants within a very short period. It was demonstrated that pre-embedded Ni NPs could not only increase the efficiency of Pd NPs but also endow the facile separation characteristic to the catalyst. Besides, the catalyst maintained favorable catalytic capacity even after five reaction cycles. In brief, this work may provide novel guidance for the maximum utilization of noble metal-modified mesoporous N-doped carbon-supported catalysts in practical applications of industrial and the treatment highly-concentration p-nitrophenol.

Electrospun NiMo nanobelts self-supported electrodes for efficient hydrogen evolution reaction in alkaline media

Transition metal compounds, as promising non-precious metal-based materials for hydrogen evolution reaction, have been limited by metal particles agglomeration. It is challenging to achieve ultra-dispersion of transition nano-metal catalysts, which would enlarge surface areas and reinforce physical stability. In this study, self-supported, highly dispersed NiMo nanobelts have been prepared by electrospinning and in-situ vacuum reduction. The unique belt structure with large active sites could facilitate the electron transfer and exhibits sufficient mechanical strength. The NiMo nanobelts show excellent HER activity, which achieve 10 mA cm−2 in 1 M KOH only required 62 mV overpotential, as well as great cycling stability.

Fracture Characterization of Base Metal, Seam Weld, and Girth Weld of Welded Line Pipe Steel at Room and Low Temperatures

For fitness-for-service assessment of pipeline cracks, it is necessary to examine toughness values of pipeline steels and their variations with temperature. In this study, experimental values of toughness (KJC) at room temperature have been obtained for base metal (BM), seam weld (SW), and girth weld (GW) in an API X65 gas transportation pipeline in order to investigate the structural integrity of whole structure. The toughness tests employed side-grooved compact tension specimens, obtained from the original pipe, to characterize the resistance to crack extension curves based on the unloading compliance technique. The values of JIC for tested specimens were found, and then, KJC values are obtained using ASTM E1820 guideline as 302, 262, and 166 MPam1/2 for BM, SW, and GW materials, respectively. Charpy V-notch (CVN) impact tests at room and low temperatures were also conducted to determine low-temperature effects on the toughness, and to examine ductile–brittle transition temperature values in the samples under study. The capability of CVN test for prediction of toughness in the tested specimens was also investigated. The error values in using CVN test results are large enough to justify that the CVN test is not suitable for prediction of toughness accurately.

The Electrochemical Tuning of Transition Metal-Based Materials for Electrocatalysis

The Electrochemical Tuning of Transition Metal-Based Materials for Electrocatalysis

Brief survey on organometalated antibacterial drugs and metal-based materials with antibacterial activity.

Rising bacterial antibiotic resistance is a global threat. To deal with it, new antibacterial agents and antiseptic materials need to be developed. One alternative in this quest is the organometallic derivatization of well-established antibacterial drugs and also the fabrication of advanced metal-based materials having antibacterial properties. Metal-based agents and materials often show new modes of antimicrobial action which enable them to overcome drug resistance in pathogenic bacterial strains. This review summarizes recent (2017–2020) progress in the field of organometallic-derived antibacterial drugs and metal-based materials having antibacterial activity. Specifically, it covers organometallic derivatives of antibacterial drugs including β-lactams, ciprofloxacin, isoniazid, trimethoprim, sulfadoxine, sulfamethoxazole, and ethambutol as well as non-antibacterial drugs like metformin, phenformin and aspirin. Recent advances and reported clinical trials in the use of metal-based nanomaterials as antibiofouling coatings on medical devices, as photocatalytic agents in indoor air pollutant control, and also as photodynamic/photothermal antimicrobial agents are also summarized.

Study on local failure conditions of nuclear containment steels

Tensile tests were performed for notched round-bar and plate specimens to acquire the local failure characteristics of SGV480 and SPV490 steels for nuclear containment structures. The notched round-bar specimens were sampled from base metals, weld joints including heat affected zone (HAZ), and simulated-HAZ materials. The simulated-HAZ materials were made using multiple heating and cooling processes with induction heating and forced air cooling. The limit strain was calculated using the Bridgman’s solution with the notch cross-sectional dimensions of the specimens, which were continuously measured with a profile projector. All notched round-bar specimens caused the tensile type ductile fracture, and there was no significant difference in the limit strains among the base metal, HAZ, and simulated-HAZ material. The limit strains were higher than the ASME VIII-2 design curve, and showed conservative results. Tensile tests using the full or partial width notched plate specimens were performed for the base metals of the two steels. In the cases of small curvature notched specimens of both full and partial widths, cracks occurred on the surface of the notch bottom and propagated into the depth of the material, until the specimens finally fractured. The limit strain plots were concentrated in a low strain and stress triaxiality position. In the cases of large curvature notched specimens of both types, no cracks occurred, and the specimens would suddenly fracture in shear after a slight shrinking of thickness. The limit strains of the notched plate specimens were lower than those of the notched round-bar specimens.