Pure Alloys Research Articles

Influence of atomic substitution on the structural stability and half-metallicity of Fe2-xCrxCoSi (x = 0 to 1) alloys

Bulk Fe2-xCrxCoSi (x = 0, 0.25, 0.5, 0.75, and 1) Heusler alloys have been prepared by arc melting method. Alloys with 0.0 ≤ x ≤ 0.75 show a highly ordered phase pure XA structure. However, 17 % of an impurity (A15 phase) was detected in the alloy with x = 1. The saturation magnetization (Ms) and Curie temperature (TC) decreased linearly with an increase in Cr content for alloys with x ≤ 0.75. Ms measured at 5 K followed the Slater–Pauling rule for half-metals. Ab initio calculations with the GGA + U approach revealed that spin polarization (P) increased with an increase in Cr and eventually reached 100 % for the alloys with x = 0.5. Though Fe-Co disorder affects P, it is still high (>98 %) for alloys with x ≥ 0.5. Despite the smaller bandgap (0.61 eV) of Fe1.5Cr0.5CoSi than FeCrCoSi (0.91 eV), it has higher Ms, elevated TC, and 100 % P. These factors, coupled with the challenges associated with obtaining phase pure FeCrCoSi alloy, make Fe1.5Cr0.5CoSi a preferred candidate for spintronic device applications.

Achieving refined microstructures and improved mechanical properties in a cup-shaped Mg-Gd-Y-Zr alloy casting by novel near-liquidus squeeze cast process

We have recently proposed a novel process named low frequency electro-magnetic stirring assisted near-liquidus squeeze cast (NSC), which has been shown effective grain refinement effect in pure Mg and binary Mg-RE alloys. In this work, the NSC process was introduced for fabricating of a cup-shaped casting by Mg-Gd-Y-Zr alloy (VW103K). The cup-shaped VW103K alloy castings fabricated by NSC process show good surface quality and dimensional accuracy, as well as with fine microstructures and no megascopic pores and surface shrinkages. At the cross section of the cup-shaped castings, the grain size, phase compositions and hardness are nearly equally distributed. The NSC processed VW103K alloy show finer average grain size and higher yield strength than that of gravity cast, squeeze cast and rheo-squeeze cast counter parts. Pouring temperature is critical and may influence the microstructure and mechanical properties of NSC processed alloys. With the decrease of pouring temperature from ∼660 to ∼630 °C, the grain size is decreased initially and then coarsened slightly, while the distribution of eutectic phase gets worse continuously. An optimal pouring temperature range of ∼660 to ∼640 °C was obtained for fabricating of VW103K alloy. The mechanisms on formation of fine microstructures in NSC processed VW103K alloys is the combined effects influenced by applied pressure, pouring temperature and the shape of mold cavity.

Ultralow magnetic susceptibility in pure and Fe(Bi)-doped Au-Pt alloys improved by structural strain regulation

Designing and manufacturing multi-component alloy samples with ultralow magnetic susceptibilityχ(<10-6cm3mol-1) is crucial for producing high-quality test masses to successfully detect gravitational wave in the LISA and TianQin projects. Previous research has idenfified AuPt alloys as a potential candidate for test masses, capable of achieving ultralow magnetic susceptibility that meets the requirements from both theoretical and experimental perspectives. In this study, we discover that the structural strain regulation (i.e. tensile and stress) can effectively optimize and further reduce the ultralow magnetic susceptibility of AuPt allpys, while fully understanding their underlying physical mechanisms. More importantly, even when doped with trace elements such as Fe or Bi impurity, strain regulation can still effectively reduce the magnetic susceptibility of the doped AuPt alloy to the desired range. Our theoretical calculations also reveal that, when the strain ratioηis controlled within in a relatively small range (<2.0%), the regulaton effect on the ultralow magnetic susceptibilities of pure or doped-AuPt alloys remains significant. This property is beneficial for achieving ultralow or even near-zero magnetic susceptibility in real AuPt alloy samples.

Enhancing microstructure, nanomechanical and tribological properties of TiAl alloy processed by spark plasma sintering with Si3N4 ceramic particulates addition

TiAl matrix composites reinforced with varying weight fractions of Si3N4 ceramic particles were successfully fabricated by the spark plasma sintering method. The microstructure, nanomechanical and tribological properties of the sintered composites were investigated. The microstructural characterization revealed the evolution of a quasi-continuous and continuous network structure consisting of minor fractions of in-situ formed Ti2AlN, unreacted Si3N4 ceramic particles and dominant Ti5Si3 intermetallic phases within the TiAl matrix at Si3N4 content above 1.5 wt%. The in-situ precipitated phases enhanced the nanomechanical and tribological properties of the composites. The 7Si3N4/TiAl composite displayed the best nanomechanical properties, including nanohardness, elastic modulus, and H/Er ratio among the sintered samples. The specific wear rate of the composites decreases with increasing reinforcement content. 7Si3N4/TiAl composite exhibited the lowest specific wear rate of 0.38 ± 0.55 10-4 mm3/Nm, representing a 95.6% improvement in wear resistance compared to the unreinforced pure TiAl alloy. The improved wear performance of the composites was attributed to their load-bearing capacity and wear resistance of the hard, in-situ Ti2AlN, Ti5Si3 and unreacted Si3N4 particles in the TiAl matrix. The composites displayed a transition from adhesive wear to predominantly abrasive wear where the hard Si3N4 particles prevented direct metal-to-metal contact and facilitated the formation of a protective tribolayer, resulting in enhanced wear resistance. Hence, the developed Si3N4/TiAl composites are suitable for various structural and tribological applications.

Comparative analysis of laser power, pure titanium, and titanium alloy effects on dendrite growth and surface morphology of TiO2-ceramic

Despite several challenges, including the inherent brittleness of ceramics, inadequate melting of the powder, and the formation of microstructural defects, laser powder bed fusion remains a promising method for ceramic fabrication. This research looks at the intricate relationship between laser power as a dominant factor in the energy density, the influence of pure titanium (Ti) and titanium alloy (Ti-6Al-4V) additives on the laser fabrication of TiO2-based ceramics, and the resultant microstructural aspects, with a particular emphasis on dendritic growth and solidification defects. The research findings revealed that changing the laser energy density has a substantial influence on the dendrite growth and solidification rate of TiO2 ceramic. However, in addition to optimizing the laser power, the addition of metal material additives also plays a significant role in regulating the melting state and controlling the part defects in ceramics. The findings support that the mixing of pure titanium showed a relatively favorable influence, enhancing the melting condition of TiO2 and yielding a smooth surface with reduced defects. Conversely, the addition of a titanium alloy (Ti-6Al-4V) has a comparatively lower positive effect and led to the formation of substantial dendrites, solidification shrinkage, and significant fractures. The change in the scanning strategy from zigzag to island has no noticeable effect on the surface morphology and dendrite formation but contributes to controlling the spattering and crack propagation.

An in vitro and in vivo study of biodegradable Zn–Cu–Li alloy with high strength and ductility fabricated by hot extrusion combined with room-temperature ECAP

Deformation processing is a commonly used strategy to improve the microstructure and hence mechanical properties of biodegradable Zn alloys. However, a single conventional processing method is usually limited in achieving this goal. In this work, hot extrusion combined with room-temperature equal channel angular pressing (ECAP) was used to fabricate biodegradable Zn–Cu–Li alloy. Compared to the hot-extruded alloy, the further ECAPed alloys have significantly finer Zn grains and precipitate more submicron- and nano-sized ε-CuZn4 particles. Moreover, the 4-pass as-ECAPed alloy exhibits the best comprehensive mechanical properties with yield strength of 315 ± 3 MPa, ultimate tensile strength of 444 ± 13 MPa and elongation of 81 ± 5%, which are 13.3%, 38.8% and 72.3% higher than those of the hot-extruded alloy, respectively. In addition, in vitro and in vivo tests were performed on the 4-pass as-ECAPed alloy to evaluate its corrosion behavior, antibacterial property, cytotoxicity and biocompatibility. In vitro results showed that the 4-pass as-ECAPed alloy exhibits better corrosion resistance than the 8-pass alloy. Also, it shows good antibacterial property, hemocompatibility and cytocompatibility. In vivo results demonstrated that the 4-pass as-ECAPed alloy exhibits faster and more uniform degradation than the pure Zn (as a control group). Both the pure Zn and 4-pass as-ECAPed alloy promote formation of new bone, the mass of which increases over time. The 4-pass as-ECAPed alloy shows slightly weaker osteogenic capacity but better overall osteointegration than the pure Zn. Furthermore, both the pure Zn and 4-pass as-ECAPed alloy exhibit good in vivo biosafety.

Investigation of Friction and Erosion Wear Properties of Titanium and Titanium Alloy Pipes.

Titanium alloys are applied in oil and gas development and transportation to improve conditions because of their high specific strength and corrosion resistance. However, the disadvantage of poor wear resistance has become an obstacle to developing titanium alloys. The friction and wear properties of pure titanium TA3 and titanium alloy TA10 were tested under different loads and different friction forms using a reciprocating friction and wear tester. Moreover, the erosion resistance of pure titanium TA3 and titanium alloy TA10 was studied using a gas-solid erosion tester. The results show that the wear rate of TA3 and titanium alloy TA10 increases with increasing friction load. Under a load of 50 N, the mass losses of TA3 under dry friction and wet friction were 0.0013 g and 0.0045 g, respectively, while the mass losses of TA10 were 0.0033 g and 0.0046 g, respectively. While the load increased to 70 N, the mass loss of TA3 was even greater, reaching 0.0065 g, and the mass loss of TA10 was 0.0058 g. The wear forms of TA3 and TA10 include abrasive wear, adhesive wear and oxidation wear. The joint action of various friction forms leads to the loss of materials. Under the simulated working conditions, the erosion rates of TA3 and TA10 were 1.01 × 10-3 g/s and 0.94 × 10-3 g/s. The erosion mechanism is the same, including plowing, indentation and cracking.

In situ growth of large-scale and ultrathin carbon nitride films shield common metal substrates from corrosion and oxidation

A centimeter-size carbon nitride (CN) film, with nanoscale thickness, is in situ deposited on various metals through the thermal condensation of melamine, achieving broad and uniform coverage, without any pre- and post-treatments. As the temperature rises, the nitrogen content in the film increases, leading to the part of CN to transform into g-C3N4. Benefit from higher Gibbs adsorption free energies of g-C3N4 with Cl- and O2 in aqueous environment, a 30 nm CN film deposited at 475 ℃ with large g-C3N4 network, minimal segregation and low internal stress enables pure metals and alloys to achieve over 90 % protection efficiency.

An investigation on effect of tramp elements and solidification processing on homogenization kinetics of AA 7xxx series aluminum alloys

AA 7068 Aluminum alloy is produced via conventional solidification (CS) and controlled diffusion solidification (CDS) processing and homogenized at 450 °C for 6 and 12 h. Optical microscopy (OM) and scanning electron microscopy (SEM) equipped with an energy dispersive x-ray spectroscope (EDS) were used to examine the as-cast and homogenized samples. It was found that although the CS sample is more chemically homogenized in the as-solidified state, the CDS sample exhibits a higher homogenization rate during the treatment. The calculated phase diagram (CALPHAD) methodology was employed to study the effect of silicon and iron on the solidification path and homogenization of the alloy. Silicon consumes magnesium atoms on the surface of the α-Al phase to form the Mg2Si phase. Therefore, the magnesium concentration on the α-Al phase required for the formation of the σ phase must be increased. Calculations shows that all the Mg atoms at this stage are completely supplied from the bulk of the αAl phase. It can be hypothesized that during the last stage of solidification, a solid/liquid diffusion couple can be created between the primary αAl and the remaining liquid for several minutes (4 min at a cooling rate of 0.2 oC/s). As a result of the activation of this couple, the Mg atoms diffuse from the α-Al bulk to its surface, and vacancies diffuse from the surface to the bulk, forming a line of Kirkendall voids. With CDS processing, the surface of the primary phase is less Mg-concentrated than that in the CS process and this significantly reduces the formation of the Mg2Si phase. Conversely, the vacancy and Mg concentration of the αAl phase in CDS is higher than that of CS and this lets other alloying elements other than Mg diffuse to the primary phase, decreasing the homogenization time. The presence of Si in the alloy leads to the formation of the Mg2Si phase, which significantly reduces the final Mg concentration in the α-Al phase after full homogenization. In the pure alloy, the Mg concentration is 2.42 wt%, while in the FeSi-containing alloy, it is reduced to 1.58 wt% due to solid solution and dispersion strengthening mechanisms. Through CDS processing, the negative impact of Si can be reduced by disrupting the mechanism of Mg2Si formation.

Effects of grain size and stacking fault energy on twinning stresses of single-phase CrxMn20Fe20Co20Ni40-x high-entropy alloys

Deformation twinning was investigated in single-phase face-centered-cubic (FCC) high-entropy alloys of the CrxMn20Fe20Co20Ni40-x system (14 ≤ x ≤ 26 at.%). The intrinsic stacking fault energies (γisf) of these alloys varied systematically across this composition range, but other physical properties that have the potential of affecting deformation twinning remained constant allowing us to isolate the effects of γisf on twinning. Tensile tests were performed at 293 and 77 K, and the tests interrupted at several different strains to evaluate deformation-induced changes in microstructure by transmission electron microscopy. The critical stress above which deformation twinning occurs was thus determined. We also evaluated how grain size (19 ≤ d ≤ 237 µm) affects the yield stress (σy) and the uniaxial critical twinning stress (σtw), which allowed us to subtract the corresponding Hall-Petch contributions and compare our polycrystalline results with experimental and theoretical data reported for single crystals. Taking into account the critical resolved shear stresses for deformation twinning in our alloys (τtw) along with those of FCC pure metals and binary alloys reported in the literature, we derived the following relationship that rationalizes most of the experimental data: τtw = 10-3G + γisf/(3·bp), where G is the shear modulus and bp is the magnitude of the Burgers vector of a Shockley partial dislocation. This expression, involving only measurable material properties, can serve as a basis for the design and optimization of new HEAs with tunable twinning stresses and, in turn, exceptional strength-ductility combinations.

Dependence of defect susceptibility on microporosity variation in Mg-xLi-3Al-1Zn casting alloys

This study quantitatively describes relative contribution of microstructural characteristics and microporosity variation to the tensile properties of Mg-xLi-3Al-1Zn alloys from the perspective of defect susceptibility. The alloys were prepared by melting pure lithium, AZ31 alloy, and additional elements in two crucibles under an Ar atmosphere, and then mixing them to add Li in the range of 2–12 wt%. As the Li content increases, the Li-rich β phase forms along the grain boundaries of the Mg-rich α phase. At approximately 12 wt% Li, the entire matrix transitions to the Li-rich β phase, and the volume density decreases from 1.762 g/cm³ (AZ31 alloy) to a minimum of 1.435 g/cm³. Additionally, the yield strength continuously increased from 67 MPa (AZ31 alloy) to approximately 120 MPa with increasing Li content, while the tensile strength increased from 127 MPa (AZ31 alloy) to a maximum of 144 MPa at 6 wt% Li, and the elongation increased to 19 % at 10 wt% Li before decreasing at higher additions. The fracture mode during tensile deformation clearly depends on the fraction of α phase and β phase, varying with Li addition. However, all tensile properties, including yield strength, are fundamentally influenced by the fractographic porosity based on the fracture surface. The defect susceptibility coefficients on microporosity variation for tensile strength and elongation, and the maximum values achievable under defect-free conditions, are highest at 6 wt% Li and 10 wt% Li, respectively. Furthermore, the relative contributions of microporosity and microstructural components to the defect susceptibility of tensile properties can be described: tensile strength increases in the order of the mixed α+β phase, β phase, and microporosity, while the contribution of the β phase to elongation is relatively lower compared to the mixed α+β phase and microporosity.

Quantitative pre-lithiation modulation of aluminum foil anode kinetics enables high rate and stable cycling of high-loading all-solid-state batteries

Aluminum (Al) foil holds great promise as a pure alloy anode for all-solid-state batteries (ASSBs) due to its suitable potential, high theoretical capacity, and excellent electronic conductivity. However, it remains challenging to achieve high reversibility and stability of the Al foil anode for ASSBs. Herein, we investigate the morphological and lithium (Li) kinetics evolutions of the Al foil anode paired with sulfide solid-state electrolyte (SSE). We identify that the significant reversible capacity loss stems from diminished Li kinetics at low Li contents (LixAl, 0 < x < 0.5), where the accumulation of pores and pure delithiated Al phase obstructs Li diffusion, increasing interfacial resistance and overpotential. Conversely, the Al foil anode with high Li contents (LixAl, 0.5 < x < 1) demonstrates reversible structures and rapid Li kinetics. Through precise pre-lithiation control, ASSBs with LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes exhibit outstanding rate capabilities and cycling stability, achieving over 4,000 cycles with 82.1 % capacity retention at 5C and demonstrating long-term cycling over 1,000 cycles with nearly 100 % capacity retention at ultra-high loadings. This work offers a viable strategy for advancing practical-level ASSBs with enhanced performance and longevity, contributing valuable insights to future battery technology.

Preparation, Mechanical Properties, and Degradation Behavior of Zn-1Fe-xSr Alloys for Biomedical Applications.

As biodegradable materials, zinc (Zn) and zinc-based alloys have attracted wide attention owing to their great potential in biomedical applications. However, the poor strength of pure Zn and binary Zn alloys limits their wide application. In this work, a stir casting method was used to prepare the Zn-1Fe-xSr (x = 0.5, 1, 1.5, 2 wt.%) ternary alloys, and the phase composition, microstructure, tensile properties, hardness, and degradation behavior were studied. The results indicated that the SrZn13 phase was generated in the Zn matrix when the Sr element was added, and the grain size of Zn-1Fe-xSr alloy decreased with the increase in Sr content. The ultimate tensile strength (UTS) and Brinell hardness increased with the increase in Sr content. The UTS and hardness of Zn-1Fe-2Sr alloy were 141.65 MPa and 87.69 HBW, which were 55.7% and 58.4% higher than those of Zn-1Fe alloy, respectively. As the Sr content increased, the corrosion current density of Zn-1Fe-xSr alloy increased, and the charge transfer resistance decreased significantly. Zn-1Fe-2Sr alloy had a degradation rate of 0.157 mg·cm-2·d-1, which was 118.1% higher than the degradation rate of Zn-1Fe alloy. Moreover, the degradation rate of Zn-1Fe-xSr alloy decreased significantly with the increase in immersion time.

Laser energy-dependent processability of non-equiatomic TiNbMoTaW high-entropy alloy through in-situ alloying of elemental feedstock powders by laser powder bed fusion

Pre-alloyed powder, which is primarily used in laser powder bed fusion (LPBF), has the disadvantages of requiring time and high manufacturing costs. To overcome these limitations, in-situ alloying, which mixes pure elemental powders and alloys them in real-time during the LPBF process, has attracted attention. In particular, manufacturing high entropy alloys (HEA) containing high-melting-point refractory elements through in-situ alloying presents considerable challenges. In this study, a non-equiatomic single body-centered cubic (BCC) solid-solution HEA was fabricated via in-situ alloying with Ti, Nb, Mo, Ta, and W powders through the LPBF process. Specifically, by applying a high volumetric energy density (VED), we successfully mitigated the segregation of constituent elements, leading to an enhanced crystallographic texture. Consequently, the reduction in the residual stress and high-angle grain boundary (HAGB) density progressed, contributing to an increased relative density. Thus, this study marks a pioneering endeavor for in-situ alloyed HEA fabrication via LPBF, illustrating the efficacy of in-situ alloying utilizing mixed powders.

Effect of heat treatment before fast multiple rotation rolling on friction surfaced Al–Si–Cu alloy

In this study the effect of combination of heat treatment of consumable rod and solid solution heat treatment before fast multiple rotation rolling (FMRR) processing on microstructure, mechanical property and wear resistance of Al–Si–Cu alloy friction surfaced on commercial pure aluminum alloy were investigated. Results show that after the FMRR process, there is a significant reduction (99% reduction) in the friction surfaced coating surface roughness. The surface roughness after FMRR processing in the coatings created by homogenized and solid solution treated consumable rod is 0.74 ± 0.12, and 0.56 ± 0.08 μm, respectively. In the coating created by homogenized rod the minimum grain size (1.7 ± 0.2 μm) formed in the FMRR processed layer. Using homogenized consumable rod and FMRR processing by rotational speed of 3000 rpm and traverse speed of 140 mm/min, the maximum hardness (9.8 ± 0.3 GPa) and minimum wear rate (4.6 ± 0.1 μg/m) created at processed layer. FMRR processing by rotational speed of 3000 rpm and traverse speed of 140 mm/min, result in 27 and 24 % increasing in hardness at friction surfaced coating created by homogenized and solid solution treated consumable rods, respectively.

Electrical impedance characterization and modelling of Ti-Β implants.

Commercially pure titanium (c.p. Ti) and Ti6Al4V alloys are the most widely used metallic biomaterials in the biomedical sector. However, their high rigidity and the controversial toxicity of their alloying elements often compromise their clinical success. The use of porous β-Titanium alloys is proposed as a solution to these issues. In this regard, it is necessary to implement economic, repetitive, and non-destructive measurement techniques that allow for the semi-quantitative evaluation of the chemical nature of the implant, its microstructural characteristics, and/or surface changes. This study proposes the use of simple measurement protocols based on electrical impedance measurements, correlating them with the porosity inherent to processing conditions (pressure and temperature), as well as the chemical composition of the implant. Results revealed a clear direct relationship between porosity and electrical impedance. The percentage and/or size of the porosity decrease with an increase in compaction pressure and temperature. Moreover, there is a notable influence of the frequency used in the measurements obtained. Additionally, the sensitivity of this measurement technique has enabled the evaluation of differences in chemical composition and the detection of intermetallics in the implants. For the first time in the literature, this research establishes relationships between stiffness and electrical impedance, using approximations and models for the observed trends. All the results obtained corroborate the appropriateness of the technique to achieve the real-time characterization of Titanium implants, in an efficient and non-invasive way.

Effect of Surface Morphologies on the In Vitro and In Vivo Properties of Biomedical Metallic Materials.

Metallic biomaterials, including traditional bioinert materials (such as stainless steel, cobalt-chromium alloys, pure titanium, and titanium alloys), novel biodegradable metals (such as pure magnesium and magnesium alloys, pure zinc and zinc alloys, and pure iron and iron alloys), and biomedical metallic glasses, have been widely used and studied as various biomedical implants and devices. Many scientists and researchers have investigated their superior biomechanical properties, corrosion behavior, and biocompatibility. However, their surface characteristics are of extreme importance due to continuing interactions between the surface/interface of an implanted metallic biomaterial and the surrounding physiological environment. Surface morphologies on these metallic biomaterials can modulate their in vitro and in vivo biological responses. In this review, we have summarized and investigated the effect of various surface morphologies on the corrosion behavior, cellular response, antibacterial activity, and osteogenesis of biomedical metallic materials. In addition, future research directions and challenges of surface morphologies on biomedical metallic materials have been elaborated. This review can lay a theoretical and practical foundation for further research and development on biomedical metallic materials.

Efficient H2O2 Synthesis through a Two-Electron Oxygen Reduction Reaction by Electrocatalysts.

The two-electron oxygen reduction reaction (2e-ORR) for the sustainable synthesis of hydrogen peroxide (H2O2) has demonstrated considerable potential for local production of this environmentally friendly chemical oxidant on small, medium, and large scales. This method offers a promising alternative to the energy-intensive anthraquinone approach, placing a primary emphasis on the development of efficient electrocatalysts. Improving the efficiency of electrocatalysts and uncovering their catalytic mechanisms are essential steps in achieving high 2e-ORR activity, selectivity, and stability. This comprehensive review summarizes recent advancements in electrocatalysts for in-situ H2O2 production, providing a detailed overview of the field. In particular, the review delves into the design, fabrication, and investigation of catalytic active sites contributing to H2O2 selectivity. Additionally, it highlights a range of electrocatalysts including pure metals and alloys, transition metal compounds, single-atom catalysts, and carbon-based catalysts for the 2e-ORR pathway. Finally, the review addresses significant challenges and opportunities for efficient H2O2 electrosynthesis, as well as potential future research directions.

Preparation of 97% pure nickel-cobalt alloy from waste Ni-MH batteries by using waste glass as a fluxing agent

With the e-waste growing rapidly all over the globe due to growing demand of electronics, smartphones, etc., coming up with an efficient and sustainable recycling process is the need of the hour. The present work reports a novel and sustainable process of manufacturing Ni alloy by bringing together three major waste streams such as waste Ni-MH batteries, e-waste plastics, and waste glass. The chosen temperature (1550 °C) favours the reduction of nickel-oxide by e-waste plastic as the reductant and sends rare earth elements present in the waste Ni-MH battery as oxide mixture to the slag phase. Waste glass powder used in this process functions as the fluxing agent, hence not requiring any additional flux. The reduction mechanism is gas-based, controlled mainly by hydrogen and carbon monoxide gases released as a result of decomposition of e-waste plastic as reaction commenced from cold zone (∼300 °C) to hot zone (1550 °C) in the horizontal tubular furnace. Formation of nickel alloy and enrichment of slag with mixture of rare earth oxides were confirmed by XRD, SEM-EDS, and Rietveld refining analysis performed on the XRD spectra of slag phase. ICP-OES (Inductively coupled plasma optical emission spectroscopy) and LIBS (laser induced breakdown spectrometer KT-100S) confirmed the high metal content in the alloy, thereby emphasizing the purity (∼98%) which is close to the composition of nickel super alloy. A maximum of 61% by weight REO enrichment was achieved in the slag phase, having La2O3:44.6%, Pr2O3:14.8%, and Nd2O3: 1.6% under optimised experimental conditions (1550 °C, 15 min, and 20% waste glass powder). This scientific investigation evinces a promising route for efficient utilisation of waste streams emanating from e-waste, thereby devising a sustainable recycling technique and protecting the environment, too.

The Application Progress of Nonthermal Plasma Technology in the Modification of Bone Implant Materials.

With the accelerating trend of global aging, bone damage caused by orthopedic diseases, such as osteoporosis and fractures, has become a shared international event. Traffic accidents, high-altitude falls, and other incidents are increasing daily, and the demand for bone implant treatment is also growing. Although extensive research has been conducted in the past decade to develop medical implants for bone regeneration and healing of body tissues, due to their low biocompatibility, weak bone integration ability, and high postoperative infection rates, pure titanium alloys, such as Ti-6A1-4V and Ti-6A1-7Nb, although widely used in clinical practice, have poor induction of phosphate deposition and wear resistance, and Ti-Zr alloy exhibits a lack of mechanical stability and processing complexity. In contrast, the Ti-Ni alloy exhibits toxicity and low thermal conductivity. Nonthermal plasma (NTP) has aroused widespread interest in synthesizing and modifying implanted materials. More and more researchers are using plasma to modify target catalysts such as changing the dispersion of active sites, adjusting electronic properties, enhancing metal carrier interactions, and changing their morphology. NTP provides an alternative option for catalysts in the modification processes of oxidation, reduction, etching, coating, and doping, especially for materials that cannot tolerate thermodynamic or thermosensitive reactions. This review will focus on applying NTP technology in bone implant material modification and analyze the overall performance of three common types of bone implant materials, including metals, ceramics, and polymers. The challenges faced by NTP material modification are also discussed.