Materials Letters: X最新文献

In this study, a uniform anomalous eutectic is formed in a slow cooling process of undercooled hypoeutectic Ni-B alloy. The longer the cooling time, the higher the hardness of the Ni₃B phase. This is a result of higher concentration of boron being arrested by the Ni₃B phase.

Renewable biomass as a sustainable feedstock has been enormously explored for the manufacturing of high value-added products such as biofuels, commodity chemicals, and new bio-based materials. The present paper describes the synthesis of a series of natural zeolite based catalysts by loading different weight percentage of phosphomolybdic acid. The efficiency of catalysts were checked by conversion of carbohydrate (glucose and fructose) to 5-HMF, which is an important industrial chemical used in the production of various value-added chemicals, materials and biofuels.

Zinc Oxide nanoparticles (ZnO NPs) were synthesized as a powder using the oxalate co-precipitation method after calcination at 700 °C. Zine sulfate was used as a zinc soluble source, and oxalic acid was used as a Catalyst. The reaction was carried out at room temperature condition. The resulted powder was characterized by XRD analysis before calcination and after calcination at 500 °C, and 700 °C. The results show that the crystal structure is hexagonal with a = 3.249 Å, c = 5.205 Å. The FeSEM results showed particles of 80 nm.

This study aims to develop spay reactive powder concrete (SRPC) with excellent mechanical and self-sensing properties by using carbon fiber (CF) as reinforcement material in combination with RPC base mix ratio. A Box–Behnken model was designed using the response surface method to study the influence of silica fume (SF), fly ash (FA), and CF on the compressive strength and strain sensitivity coefficient (SSC) of SRPC with different dosages. Variance regression was used to analyze the interaction of each factor on the index, and multi-index optimization technology was utilized to optimize the response scheme. Results show that the compressive strength is 107.272 MPa and SSC is 34.429 under optimized conditions of 18% SF, 17.097% FA, and 0.5% CF. The strain sensitivity coefficient of SRPC is 5–17 times higher than that of the conventional strain gauge used for monitoring concrete. SRPC was prepared by adjusting the dosage of the water reducer and stirring time at a 0.2 water–binder ratio.

With good electrochemical performances and cost advantages, sodium-ion batteries (SIBs) have great potential in energy storage and other fields. It is crucial to research anode materials for SIBs with high performance and low cost to promote large-scale industrialization. In this study, the amorphous carbon-based anodes prepared by one-step carbonization of bituminous coal were firstly reported. When the materials were worked as anodes for SIBs in the voltage range of 0–1.5 V, an excellent reversible capacity of 270 mAh·g⁻¹ and an initial coulombic efficiency (ICE) of 84.4% were achieved at a current density of 35 mA·g⁻¹. More impressively, the carbon anodes possess merits of low cost, making the designed carbon anodes practicable to the industrial applications.

Continuous Kr ion irradiation at 400 °C with damage level up to 40 dpa was performed in Zircaloy-4 to investigate the surface damage features of α-Zr matrix. Atomic force microscopy confirms that the irradiation induced surface damage is primarily in the form of damaged pits. The increasing Ra value indicates the gradual surface roughening process with continuous irradiation. The irradiation-induced surface roughening mechanism is suggested as three stages: stage I, the formation and growth along depth direction of damaged pits at low doses; stage II, the extension of damaged region within the surface; stage III, layer by layer removal of surface atoms once the undamaged matrix is depleted.

The work focuses on the potential ability of 1-ethyl-3-methyl imidazolium ethyl sulphate (EMIES) and 1-butyl-3-methyl-imidazolium tetra chloro aluminate (ITCA) ionic liquids (IL) as reducing agents in the synthesis of activated silver colloidal particles without using any external reducing agent. The formation of activated silver colloidal particles from silver nitrate salt is explained based on the characterization results such as EDAX and SEM. The absorbance of the EMIES and ITCA impregnated activated silver particles are analysed by UV spectral study and the presence of functional groups are successfully determined by FT-IR spectrum. In this study, we also investigate antibacterial and antioxidant applications of EMIES, ITCA and impregnated silver colloidal particles. The antibacterial activity investigated by disc diffusion method and antioxidant activity by DPPH method.

Fiber-reinforced polymers are increasingly used in lightweight applications due to their high specific properties. Different polymer materials, and fiber architectures, are commercially available for structural applications. Performing fatigue experiments on all these combinations of fiber–matrix composites up to 10⁹ cycles to mimic their typical lifetime of 15–20 years, at a low testing frequency generally in the range of 5–10 Hz in applications such as the aerospace industry, is expensive and time-consuming. In this study, a test system to investigate the very high cycle fatigue (VHCF) behavior of continuous fiber-reinforced polymers under an axial loading (tension–compression) condition is proposed. To do so, a testing system capable of applying cyclic oscillations at a frequency of 20 kHz and stress ratio, R = -1 was developed. For this investigation, the carbon fiber reinforced in Polyether-ketone-ketone (CF-PEKK) material was chosen. For visualization of the specimen oscillation-mode at 20 kHz, video-imaging using a high-speed camera (HSC) was employed. With the obtained displacement field from the HSC images and with thermography, the desired specimen response due to resonance at 20 kHz is validated.

A promising arc enhanced glow discharge (AEGD) was developed to enhance hot corrosion resistance of NiCoCrAlY/AlSiY coating. The AlSiY layer exhibited loose texture accompanied by plenty of pores, which triggered the muti-scale diffusion of salt mixture resulting in severe corrosion degradation of coating texture and rapid diffusion of NiCoCrAlY layer. However, the AEGD-assisted AlSiY layer showed dense texture, which effectively prevented the diffusion of salt mixture and suppressed the corrosion reaction as well as the diffusion of NiCoCrAlY layer. The results confirmed that AEGD showed a huge potential to inhibit the corrosion damage and diffusion of thermal protective coatings.

Direct Laser Interference Patterning (DLIP) is used to generate textured stainless steel surfaces to control the wettability of a liquid nickel-based brazing alloy. The interference of two laser beams leads to periodic line-like structures with a spatial period of 6.0 µm. A maximum structure depth of 2.0 µm is reached by controlling the processing parameters. Moreover, the generation of laser induces periodic surface structures (LIPSS) with a period of ∼ 800 nm is observed on top of the DLIP structures. Depending on the produced texture depth, the contact angle of the molten metal is increased from 13° up to 96°. This allows adjusting the contact angle for various brazing and soldering applications and can also be used as a filler metal stop.