As a fundamental pillar for fostering new quality productive forces, constructing
a modern industrial system and safeguarding national comprehensive security, the new
materials industry underpins the core competitiveness of high-end manufacturing and
cutting-edge technologies. Today's global industrial landscape is undergoing profound
restructuring driven by four pivotal forces：intensifying geopolitical competition,
worldwide carbon peaking and carbon neutrality transitions, in-depth integration of
digital and intelligent technologies, and targeted iteration of materials spurred
by diverse downstream application scenarios. In parallel, artificial intelligence,
big data and high-throughput computing are revolutionizing the traditional trial-and-error
R&D paradigm of materials science, enabling data-driven material screening, inverse
structural design and intelligent process optimization to drastically cut research
cycles and experimental costs. This paper systematically sorted out the opportunities
and structural risks confronting the global new materials industry, and thoroughly
reviewed the strategic arrangements rolled out by the United States, the European
Union, Germany, the United Kingdom, Japan and Russia in 2025 and 2026. U.S. tied new
materials closely to national defense and technological security, launching special
programs including Crystal Palace and Carbon Crunch for military advanced materials,
and consolidated independent supply chains for semiconductor materials through the
CHIPS and Science Act, alongside initiatives to supervise critical mineral resources
and apply AI to accelerate material innovation. EU centered its strategy on European
strategic autonomy and green transformation, advancing the Advanced Materials Act
and the Critical Raw Materials Act to diversify mineral supply, developed circular
materials and set global green trade standards. Germany, UK, Japan and Russia had
also introduced targeted national plans respectively, focusing on technological sovereignty,
digitalized material R&D, military-civilian integrated innovation, rare earth recycling
and import substitution amid geopolitical sanctions. After years of policy support
and technological accumulation, China had achieved remarkable breakthroughs in lithium
battery materials, rare earth functional materials and general carbon fibers, with
a batch of national key innovation platforms and specialized sophisticated enterprises
cultivated. Nevertheless, prominent internal and external vulnerabilities persisted.
Externally, fierce global technological competition and restrictive trade policies
created severe "bottleneck" risks, as high-end photoresists, single-crystal superalloys,
core manufacturing equipment and other strategic materials still relied heavily on
imports, and China lacked sufficient discourse power in formulating international
material standards. Targeting six core strategic fields with prominent security risks,
this study proposed targeted development frameworks for self-reliant industrial construction.
For micro-nano electronic manufacturing, it highlighted localized substitution of
bottleneck materials such as photoresists and electronic specialty gases, alongside
R&D of low-dielectric materials and wide-bandgap semiconductor supporting materials
to match advanced packaging and high-performance chip demands. For aerospace, it advocated
full-chain independent manufacturing of high-performance carbon fibers, single-crystal
superalloys and ceramic matrix composites to satisfy extreme service conditions of
hypersonic vehicles and reusable rockets. For robotics and sensors, priorities covered
lightweight structural alloys, rare earth permanent magnets and flexible sensing materials
to support bionic robots and precision perception systems. In advanced nuclear energy,
the paper stressed breakthroughs in radiation-resistant cladding materials and low-activation
structural alloys to support fourth-generation reactors and space nuclear power sources.
For marine engineering equipment, corrosion-resistant high-strength steel and deep-sea
functional materials were key to advancing polar vessels and offshore renewable energy
infrastructure. To systematically resolve industrial security challenges, this paper
put forward multi-dimensional countermeasures covering five core dimensions. First,
innovation-driven development shall be strengthened via the new whole-of-nation system
to tackle generic bottleneck technologies, improve the commercialization system of
scientific achievements and optimize intellectual property management for strategic
materials. Second, supply chain resilience would be reinforced through domestic mineral
exploration, diversified cross-border resource cooperation, national strategic mineral
reserves and digital risk early warning platforms. Third, an integrated standard system
aligned with international norms shall be established to fill standard gaps in high-end
materials and implement full-lifecycle quality traceability management. Fourth, a
multi-level talent training matrix would be optimized through industry-university-research
integration, performance evaluation reforms and market-oriented incentive mechanisms
to address talent shortages. Fifth, the industrial ecosystem would be upgraded through
targeted policy support for industrial clusters, intelligent production line transformation
and low-carbon circular manufacturing to advance high-end, intelligent and green development
simultaneously. In summary, the safety of the new materials industry constituted an
indispensable foundation of national industrial and scientific security. Faced with
sweeping global industrial reshuffling and fierce international competition, China
must advance coordinated upgrades across technological innovation, supply chain robustness,
standardization, talent cultivation and industrial ecology. The conclusions and suggestions
of this research could provide theoretical reference and practical guidance for constructing
an independent, controllable, safe and efficient new materials industrial system,
consolidating the bottom line of national scientific and industrial security, and
fueling the steady growth of new quality productive forces and the advancement of
new industrialization.
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Aluminum alloys are widely appliedd in the aerospace industry due to their excellent
mechanical properties, superior corrosion resistance, good machinability, high strength
to density ratio, and desirable electrical and thermal conductivity. So far, the aluminization
application ratio of civil aircraft exceeds 70%, while that of military aircraft is
more than 48%. Among them, the second series of aluminum alloys （Al, Cu, Mg）, as heat-treatable
strengthend aluminum alloys, have excellent mechanical properties. Therefore, they
are widly used as aircraft structural materials. In recent years, 2324 aluminum alloy
has been optimized by regulating the content of alloying elements and optimizing heat
treatment processes, endowing it with excellent mechanical properties. After aging
treatment, the second phases mainly include S', S and T phases. It is notable that
S phase acts as the main strengthening phase at room temperature for 2324 aluminum
alloy. T phase is the high-temperature strengthening phase, which is a brittle phase
at room temperature and there by deteriorates the comprehensive performance of the
alloy. In-depth researchon S-phase can help to improve the performance of 2324 aluminum
alloy. In this paper, the strain field and nucleation process around S-phase in 2324
aluminum alloy were systematically studied. With transmission electron microscopy
（TEM） and differential scanning calorimetry （DSC）, the strain field and nucleation
kinetics around S-phase during aging were investigated. The strain field around S-phase
and its intrinsic characteristics were revealed, and the relationship between activation
energy and transformation fraction, as well as nucleation mechanism of S-phase, were
elucidated. The results showed that a strong stress field existed around the early-formed
S-phase, and the stress magnitude decreased with the increasing distance from S-phase.
The size of S-phase also affected the surrounding stress field, and the smaller the
width of S-phase, the higher the surrounding stress field. On the one hand, S-phase
was incoherent with the alloy matrix, the lattice mismatch between the two phases
induced the formation of a stress field. The calculated lattice mismatch were –1.25%,
1.92%, and –1.45% for ［100］S//［100］Al, ［010］S//［012］Al, ［001］S//［021］Al, respectively. On the other hand, there were diffused Cu/Mg atoms around S phase,
and the concentration of diffused atoms was distributed in a gradient along the direction
away from S-phase. In general, the concentration of Cu/Mg atoms was high in the region
close to S-phase and low in the region far away from it. Since the atomic sizes of
Cu and Mg atoms differed greatly from that of the aluminum atoms of the matrix, a
stress field was formed around S-phase. In summary, the stress field around S-phase
resulted fromthe superposition of two contributions：the stress field generated by
the lattice mismatch and Cu/Mg solute atoms. Moreover, all characteristic temperatures
of S'-phase increased with rising heating rate, indicating that the formation and
dissolution of S' and S-phase were controlled by the reaction kinetics and exhibited
thermal activation characteristics. In addition, the magnitude of precipitation decreased
as the increase of the heating rate, which could be explained by the enhanced solid
solubility of Cu at a higher heating rates. The average values of the activation energies
for the precipitation of S' and S-phases calculated by Kissinger method were 76.65
and 119.57 kJ·mol−1, respectively, and corresponded to vacancy migration energies of 41 and 66.9 kJ·mol−1 in Al-Cu-Mg alloy, respectively. Therefore, the precipitation of S' and S phases
was governed by multiple factors rather thanmerley the diffusion of Cu atoms. Then,
as the heating rate increased, the temperature was higher for the transformation fraction,
indicating that the transformation degree increased with the rising heating rate and
temperature. These features could be explained from two aspects：1） at a certain heating
rate, the diffusion of solute atoms was enhanced with increasing temperature, thereby
promoting the transformation； 2） at a fixed temperature, as the heating rate decreased,
the solute atoms had enough time to diffuse, thus increasing the transformation fraction.
The apparent activation energies E calculated by the Analytical method were 84.98 and 148.53 kJ·mol−1 for S and S' phases, respectively. The activation energy required for S'-phase formation
decreased with the increase of transformation fraction, and the activation energy
during the formation of S-phase increases with the increase of the conversion rate.
The decreasing activation energy of S'-phase was due to the gradual increase in the
nucleation sites during aging. The increase in S-phase activation energy was due to
the decrease in alloying elements and dislocations in the matrix with prolonged aging,
making the nucleation of S-phase increasingly difficult and requiring higher activation
energy. In conclusion, the activation energy of S'-phase decreased with the increase
of the transformation fraction, and the activation energy of S-phase increased with
the increase of the transformation fraction.
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Ti-6Al-4V（TC4）, as an excellent dual-phase titanium alloy, exhibits good thermal stability
at high temperatures and possesses superior overall performance, leading to its extensive
use in the aerospace industry. Due to the complex geometries and poor room-temperature
formability of titanium alloys, hot forming processes are typically employed during
manufacturing. However, TC4 alloy has a narrow hot working window, where the microstructure
is highly sensitive to deformation parameters. The competition among deformation mechanisms
such as dynamic recrystallization（DRX）, work hardening（WH）, and dynamic recovery（DRV）complicates
microstructural evolution during high-temperature deformation. Therefore, investigating
the effects of deformation parameters on microstructural evolution and corresponding
deformation mechanisms is crucial. Traditionally, hot compression tests are used to
evaluate alloy forming processes. However, in the complex process of hot stamping
of intricate parts, tensile stresses may lead to accumulated damage, significantly
reducing final mechanical performance. High-temperature tensile tests accurately reflect
the stress state during material deformation. The tensile deformation behavior of
titanium alloys differs in mechanism from hot compression, making it essential to
elucidate the evolution of microstructure during high-temperature tensile deformation
for a better understanding of mechanical property changes. Previous studies have indicated
that high-temperature deformation of TC4 alloy involves complex microstructural changes
such as processing hardening due to dynamic grain growth, deformation and high-temperature
movement of intragranular dislocations, α→β phase transformation, globularization
of lamellar α phase, dynamic recovery, and dynamic recrystallization. Consequently,
material mechanical properties undergo intricate changes, necessitating exploration
of TC4 titanium alloy's mechanical characteristics under different high-temperature
conditions. The plastic deformation capability of the alloy fundamentally reflects
the macro results of its internal microstructural deformation mechanism. A systematic
study on the tensile deformation behavior of TC4 alloy within a broad temperature
range for hot forming is currently lacking. Therefore, this paper conducted high-temperature
tensile experiments at temperatures of 650, 700, 750, 800 and 850 ℃ with a strain
rate of 0.02 s-1, employing electron backscatter diffraction （EBSD） to analyze the tensile microstructure
characteristics and deformation mechanisms of TC4 alloy post-deformation. The formation
process of recrystallized grains was reflected by changes in orientation difference
angles, and individual grains were selected to analyze the globularization process
of lamellar structures. The phase diagrams and image quality maps were used to reveal
α-β phase transformation of TC4 alloy. The results showed that：1） TC4 alloy exhibited
different deformation characteristics during high-temperature tensile processes. With
increasing deformation temperature, yield stress gradually decreased. At 650 ℃, yield
stress increased with loading, peaks, and then rapidly decreased until fracture, exhibiting
significant work hardening characteristics. At 700 and 750 ℃, yield stress reached
a maximum early in deformation, followed by dynamic softening, indicating DRV characteristics.
At 800 and 850 ℃, yield stress peaked early in deformation and then decreased gradually
with increasing strain, where dynamic recrystallization played a dominant role, resulting
in decreased strength and significantly increased elongation. 2） Fracture surface
analysis revealed that at lower temperatures, dimples were smaller and deeper, with
uneven distribution and presence of microcracks and numerous voids at fracture surfaces.
As temperature increased, dimples became larger and shallower, indicating increased
plasticity, consistent with macro trends in elongation. 3） During high-temperature
deformation of TC4 alloy, significant differences were observed in microstructural
morphology. At 650 ℃, primary α phase exhibited elongated distribution with relatively
low equiaxed transformation. Local recrystallization occurred in grain boundaries
of α-p phase, forming "necklace-like" recrystallized grains. As temperature rose to
700 and 750 ℃, dynamic softening did not fully dissipate energy from thermal deformation,
leading to dynamic precipitation of lamellar α phase, with increased thickness of
lamellar α phase with temperature rise. At 800 ℃, thinner α phase lamellae transformed
into finer recrystallized grains, undergoing dynamic globularization process, with
average DRX grain size approximately 1.04 μm. Increasing to 850 ℃, volume fraction
of recrystallized grains increased, including those formed at α-p phase grain boundaries
and globularization of lamellar α phase. Overall, with increasing tensile temperature,
primary α phase tended towards equiaxial transformation, decreasing aspect ratio from
1.67 to 1.35, with grain size initially increasing and then decreasing. Low-angle
grain boundaries（LAGBs）gradually transformed into high-angle grain boundaries（HAGBs）,
with HAGBs content increasing from 11.7% to 36.1%, indicating enhanced DRX effects.
High-temperature tensile process of TC4 alloy was controlled by multiple deformation
mechanisms, primarily including DRV mechanism, DRX mechanism, α→β phase transformation,
lamellar α phase globularization mechanism, and grain boundary sliding（GBS）mechanism.
DRV and continuous dynamic recrystallization（CDRX）mainly controled flow softening
process of TC4 alloy, with CDRX mechanism continuously transitioning from LAGBs to
HAGBs. Discontinuous dynamic recrystallization（DDRX）phenomenon was observed even at
lower temperatures（650 ℃）. α→β phase transformation was a critical factor in enhancing
alloy plasticity, with decreasing volume fraction of αp phase and increasing α→β phase transformation with temperature rise. Dynamic globularization
of lamellar α phase initially occurred in thinner lamellar layers, eventually forming
fine and uniform DRX grains.
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Given the challenges posed by the low hardness and inadequate wear resistance of Ti-6Al-4V
alloy, this research aimed to explore an innovative solution by employing the laser
cladding technique to develop high-entropy alloy（HEA）coatings composed of TiZrNbCrCo
on the alloy's surface. The primary objectives were to investigate the effects of
varying the number of cladding layers on the elemental composition and to assess how
these variations influenced the phase constitution, microstructure, microhardness,
wear, and electrochemical properties of HEA coatings. To predict the phase composition
of the solid solution phases in HEA coatings with different layer numbers, empirical
thermophysical parameters were utilized. The methodology encompassed a detailed experimental
setup where the laser cladding process was meticulously optimized to fabricate coatings
with varying numbers of layers. This approach enabled the controlled manipulation
of the dilution rate and elemental distribution within the coatings, thereby allowing
for a comprehensive analysis of the resulting phase and microstructural characteristics.
The coatings were systematically analyzed using X-ray diffraction（XRD）to identify
their phase compositions and scanning electron microscopy to elucidate their microstructures.
Microhardness measurements were conducted to evaluate the mechanical enhancements,
while wear tests were performed to assess the wear resistance of the coatings. Furthermore,
electrochemical tests in a 3.5%NaCl solution were carried out to determine the coatings'
corrosion resistance. The results revealed that all coatings, exhibited a consistent
phase composition, predominantly featuring a body-centered cubic （bcc） structured
solid solution phase. This phase was characterized by dendrites rich in Nb and inter-dendrites
rich in Co. It was observed that an increase in the number of cladding layers led
to a decrease in the dilution rate, which in turn facilitated the formation of petal-like
Laves phases enriched in Co and Zr, along with α-Ti precipitates enriched in Zr. Remarkably,
the average microhardness of the coatings reached HV0.1747.7, approximately 2.33 times that of the substrate. This significant enhancement
in microhardness translated to a reduction in wear volume by 68.6% compared to the
substrate. The optimal corrosion resistance was achieved with a two-layer configuration,
which exhibited the lowest self-corrosion current （6.46×10−6 A·cm−2） a larger self-corrosion potential （-0.286 V）, and the lowest corrosion rate, indicating
a substantial improvement in corrosion resistance. The conclusion drawn from this
study highlighted the critical role of laser cladding parameters in influencing the
microstructural and compositional characteristics of HEA coatings. The enhancement
in mechanical and chemical properties could be attributed to the strategic manipulation
of the number of cladding layers, which optimized the microstructural features such
as the distribution of Laves phases and α-Ti precipitates. Moreover, this research
contributed to the broader academic discourse by elucidating the relationship between
laser cladding parameters, microstructural evolution, and the resulting properties
of HEA coatings. In summary, this comprehensive investigation into the development
and characterization of TiZrNbCrCo high-entropy alloy coatings on Ti-6Al-4V alloy
surfaces provided a promising approach for addressing the limitations of conventional
titanium alloys. The research outcomes not only demonstrated the feasibility of significantly
enhancing the hardness, wear, and corrosion resistance of Ti-6Al-4V alloys through
laser cladded HEA coatings but also opened up opportunities for using high-entropy
alloys in surface engineering to meet the needs of modern industries.
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Silicon(Si)-based anodes are widely recognized as the most promising alternatives
to conventional graphite anodes for lithium-ion batteries(LIBs), owing to their ultrahigh
theoretical specific capacity(4200 mAh·g-1), lowlithiation potential, abundant crustal reserves, low toxicity, and cost-effectiveness.
However, their large-scale commercialization is severely hindered by two intrinsic
challenges：1) drastic volume expansion(>300%)during lithiation/delithiation, which
induces particle pulverization, electrode integrity degradation, and continuous rupture/reformation
of the solid electrolyte interphase(SEI)films, thereby causing irreversible lithium-ion
consumption； 2) extremely low intrinsic electrical conductivity(1×10-4 S·cm-1), which restricts ion/electron transport kinetics and thus degrades rate capability.To
address these issues, early research efforts focused on nano-engineering of Si and
the development of Si-based composites. Nanostructured Si can partially alleviate
mechanical fracture by accommodating strain through size-dependent deformation mechanisms；
however, it tends to agglomerate during prolonged cycling and exhibits excessive side
reactions with the electrolyte, reducing the initial Coulombic efficiency(ICE)and
cycling lifespan. Si/carbon(Si/C)composites design, which take advantage of the high
electrical conductivity, chemical stability, and mechanical flexibility of carbon
matrices, have emerged as a primary route toward commercialization. Nevertheless,
challenges related to the inherently low conductivity of Si and inadequate interfacial
bonding between Si and carbon remain unresolved. Against this backdrop, this review
emphasized doping modification as a fundamental strategy to enhance the electrochemical
performance of Si-based anodes. Starting from the lithium storage mechanism of Si—which
stored lithium via an alloying/dealloying reaction to form various Li-Si alloys, with
a theoretical maximum lithiation phase of Li22Si5 accommodating 4.4 Li atoms per Si atom—and its core limitations, we systematically
analyzed the regulation mechanisms and functional effects of different doping approaches.
These were categorized into three types：non-metallic (heteroatom) doping, metallic
doping, and multi-element co-doping. Non-metallic doping(e.g., with B, P, N, or S)effectively
modulated the electronic structure of Si-based materials, improved Li+ transport pathways, enhanced electronic conductivity, and promoted the formation
of a more stable SEI layer. Metallic doping was subdivided into two categories：electrochemically
inactive metals(e.g., Fe, Ti), which enhanced electrical conduction and provided mechanical
reinforcement to alleviate volume expansion, and electrochemically active metals(e.g.,
Mg, Ge), which contributed additional capacity and helped accommodate volume expansion
through synergistic alloying behavior. Multi-element co-doping(including non-metal/non-metal
and metal/non-metal combinations)achieved synergistic optimization of multiple physicochemical
properties, thus further enhancing conductivity, structural stability, and fast-charging
performance. Finally, this review outlined future perspectives for doping modification
technologies in Si-based anodes, including the exploration of novel co-doping systems
to simultaneously address conductivity, volume expansion, and SEI stability； the optimization
of doping processes for precise control over elemental distribution and concentration；
and the integration of in-situ characterization techniques to deepen the understanding
of the influence of doping elements on the lithium storage mechanism. This review
aimed to provide fundamental theoretical insights and practical technical guidance
for the development of high-energy-density and fast-charging Si-based anode materials,
thereby accelerating their commercial adoption.
Cited: 0
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As a fundamental pillar for fostering new quality productive forces, constructing
a modern industrial system and safeguarding national comprehensive security, the new
materials industry underpins the core competitiveness of high-end manufacturing and
cutting-edge technologies. Today's global industrial landscape is undergoing profound
restructuring driven by four pivotal forces：intensifying geopolitical competition,
worldwide carbon peaking and carbon neutrality transitions, in-depth integration of
digital and intelligent technologies, and targeted iteration of materials spurred
by diverse downstream application scenarios. In parallel, artificial intelligence,
big data and high-throughput computing are revolutionizing the traditional trial-and-error
R&D paradigm of materials science, enabling data-driven material screening, inverse
structural design and intelligent process optimization to drastically cut research
cycles and experimental costs. This paper systematically sorted out the opportunities
and structural risks confronting the global new materials industry, and thoroughly
reviewed the strategic arrangements rolled out by the United States, the European
Union, Germany, the United Kingdom, Japan and Russia in 2025 and 2026. U.S. tied new
materials closely to national defense and technological security, launching special
programs including Crystal Palace and Carbon Crunch for military advanced materials,
and consolidated independent supply chains for semiconductor materials through the
CHIPS and Science Act, alongside initiatives to supervise critical mineral resources
and apply AI to accelerate material innovation. EU centered its strategy on European
strategic autonomy and green transformation, advancing the Advanced Materials Act
and the Critical Raw Materials Act to diversify mineral supply, developed circular
materials and set global green trade standards. Germany, UK, Japan and Russia had
also introduced targeted national plans respectively, focusing on technological sovereignty,
digitalized material R&D, military-civilian integrated innovation, rare earth recycling
and import substitution amid geopolitical sanctions. After years of policy support
and technological accumulation, China had achieved remarkable breakthroughs in lithium
battery materials, rare earth functional materials and general carbon fibers, with
a batch of national key innovation platforms and specialized sophisticated enterprises
cultivated. Nevertheless, prominent internal and external vulnerabilities persisted.
Externally, fierce global technological competition and restrictive trade policies
created severe "bottleneck" risks, as high-end photoresists, single-crystal superalloys,
core manufacturing equipment and other strategic materials still relied heavily on
imports, and China lacked sufficient discourse power in formulating international
material standards. Targeting six core strategic fields with prominent security risks,
this study proposed targeted development frameworks for self-reliant industrial construction.
For micro-nano electronic manufacturing, it highlighted localized substitution of
bottleneck materials such as photoresists and electronic specialty gases, alongside
R&D of low-dielectric materials and wide-bandgap semiconductor supporting materials
to match advanced packaging and high-performance chip demands. For aerospace, it advocated
full-chain independent manufacturing of high-performance carbon fibers, single-crystal
superalloys and ceramic matrix composites to satisfy extreme service conditions of
hypersonic vehicles and reusable rockets. For robotics and sensors, priorities covered
lightweight structural alloys, rare earth permanent magnets and flexible sensing materials
to support bionic robots and precision perception systems. In advanced nuclear energy,
the paper stressed breakthroughs in radiation-resistant cladding materials and low-activation
structural alloys to support fourth-generation reactors and space nuclear power sources.
For marine engineering equipment, corrosion-resistant high-strength steel and deep-sea
functional materials were key to advancing polar vessels and offshore renewable energy
infrastructure. To systematically resolve industrial security challenges, this paper
put forward multi-dimensional countermeasures covering five core dimensions. First,
innovation-driven development shall be strengthened via the new whole-of-nation system
to tackle generic bottleneck technologies, improve the commercialization system of
scientific achievements and optimize intellectual property management for strategic
materials. Second, supply chain resilience would be reinforced through domestic mineral
exploration, diversified cross-border resource cooperation, national strategic mineral
reserves and digital risk early warning platforms. Third, an integrated standard system
aligned with international norms shall be established to fill standard gaps in high-end
materials and implement full-lifecycle quality traceability management. Fourth, a
multi-level talent training matrix would be optimized through industry-university-research
integration, performance evaluation reforms and market-oriented incentive mechanisms
to address talent shortages. Fifth, the industrial ecosystem would be upgraded through
targeted policy support for industrial clusters, intelligent production line transformation
and low-carbon circular manufacturing to advance high-end, intelligent and green development
simultaneously. In summary, the safety of the new materials industry constituted an
indispensable foundation of national industrial and scientific security. Faced with
sweeping global industrial reshuffling and fierce international competition, China
must advance coordinated upgrades across technological innovation, supply chain robustness,
standardization, talent cultivation and industrial ecology. The conclusions and suggestions
of this research could provide theoretical reference and practical guidance for constructing
an independent, controllable, safe and efficient new materials industrial system,
consolidating the bottom line of national scientific and industrial security, and
fueling the steady growth of new quality productive forces and the advancement of
new industrialization.
Cited: 0
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Lithium-excess disordered rock-salt (DRX) materials have emerged as promising cathode
candidates owing to their high capacity and energy density. Although short-range ordering
(SRO) has been reported in DRX material Li1.16Ti0.37Ni0.37Nb0.10O2，quantitative analysis of its real-space structural origin remains scarce. Therefore，this
paper mainly characterized Li1.1Mn0.8Ti0.1O1.9F0.1 using spherical aberration-corrected transmission electron microscopy (TEM). Through
a series of tilting experiments，the distribution of diffuse scattering bands was identified.
Quantitative analysis of atomic-resolution images confirmed that these diffuse bands
in electron diffraction arised mainly from intensity variations within the transition-metal
(TM) cation columns，indicating that SRO originated from the specific distribution
of cations. For comparison，Li1.05Mn0.85Ti0.1O2 without F was also designed，and it was found that the ordering was significantly
enhanced. These results suggested that fluorination might correlate with the improved
electrochemical performance via its influence on SRO. The arrangement of disordered
cations and the concentration of vacancies directly affected Li percolation pathways
and consequently the electrochemical behavior of DRX anodes. Li1.05Mn0.85Ti0.1O2 (LMTO) and Li1.1Mn0.8Ti0.1O1.9F0.1 (LMTOF) were synthesized by weighing stoichiometric amounts of Li2CO3，Mn2O3，TiO2，and LiF，and mixing them in a ZrO2 ball-milling jar. The mixture was ball-milled at 600 r·min−1 for 6 h，then heated in a tube furnace under an inert atmosphere at a rate of 3 ℃·min−1 to 1100 ℃，held for 20 min，and cooled naturally to room temperature. To avoid Ga+ beam damage during focused ion beam (FIB) sampling，atomic-resolution images were
obtained from particles directly dispersed onto microgrids via ultrasonication. For
TEM observation，powder samples were ultrasonically dispersed in dimethyl carbonate
and deposited onto carbon films or grids. Selected-area diffraction patterns were
acquired using a JEOL JEM-F200 thermal field-emission TEM，with the beam positioned
at thin particle edges. High-angle annular dark-field scanning TEM (HAADF-STEM) images
were obtained using a JEOL JEM-ARM200F cold field-emission microscope equipped with
a spherical-aberration corrector，operated at 200 kV with a collection angle of 50~200
mrad. Fast Fourier transform (FFT) patterns showing clear diffuse bands were processed
using Calatom software，involving filtering，Fourier transform，and inverse Fourier transform
of HAADF-STEM images. Periodic structures yield sharp Bragg spots in Fourier space，while
diffuse scattering was distributed throughout reciprocal space. To extract triple-periodic
structural information，appropriate filtering windows were applied around major Bragg
reflections before inverse Fourier transformation. Calatom analysis showed that diffuse
bands in experimental FFT patterns correspond to variations in TM column intensity
rather than positional disorder. In Li1.1Mn0.8Ti0.1O1.9F0.1，SRO primarily resulted from intensity variations of Ti/Mn cation columns，likely influenced
by Li site occupancy. Filtering that retains superstructure information in FFT led
to periodic strong-weak intensity modulation of atomic columns，whereas filtering only
the main reflections yield homogeneous intensity. Since HAADF intensity scales with
atomic number，and only Ti and Mn were visible along ［001］ zone axis，the observed superstructure
in Li1.1Mn0.8Ti0.1O2 could be attributed to SRO similar to that in the fluorinated sample. This implied
that the superstructure was related to TM column intensity variations associated with
ordered Li occupancy. In Li1.1Mn0.8Ti0.1O2，enhanced ordering was observed，with elongated superstructure reflections appearing
at wave vectors q1=a*–0.5b*，q2=0.5a*–0.5b*，and q3=0.5a*–b*，indicating cation ordering. These results suggested that F-doping improved capacity
retention by reducing cation (including Li) ordering. The SRO of TM cations within
the disordered lattice significantly influenced Li percolation channels during cycling.
Therefore，understanding DRX structures at the atomic scale could guide the design
and optimization of high-performance Li-excess disordered rock-salt cathodes.
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Metallurgical processes of tin are pyrometallurgical refining and electrorefining.
Compared with pyrometallurgical refining，although the tin produced by electrorefining
accounts for less total tin production，it has the advantages of short process and
high product purity. At present，the electrorefining of tin is generally carried out
in the fluorosilicic acid system with the assistance of bone glue and β-naphthol.
The high saturated vapor pressure and low stability of fluorosilicic acid will cause
a certain burden on the environment，which is contrary to the purpose of green and
sustainable development of metallurgy. According to research reports，methanesulfonic
acid （MSA）is a strong organic acid，which is very stable for chemical oxidation and
reduction. In addition，it does not tend to hydrolyze in water and has the advantages
of low toxicity，low volatility，high stability and conductivity，and easy treatment
of waste liquid. It is an ideal acid in hydrometallurgy. In addition，in terms of additives，bone
glue，lignosulfonate，and other ingredients from natural animal bones and plant additives
are unstable，resulting in variability of relative molecular mass and structural uncertainty
and complexity of actual production. With the technology development trend of green，energy-saving
and sustainable metallurgical construction becoming more and more obvious，it is urgent
to develop a green method for tin production. Therefore，the chemical synthesis additive
assisted MSA electrolyte for tin electrorefining，with high stability and designability，has
a greener application prospect. The rectifier was used to provide direct current for
the electrolysis system，and the circulation system of the electrolyte with a constant
temperature control system and a peristaltic pump was used to carry out the electrorefining
test. The energy consumption and morphology were adjusted，and the simulation and verification
of electrorefining were carried out. The electrochemical behavior of Lugalvan BNO12
on tin electrodeposition in methanesulfonic acid system was studied by cyclic voltammetry，and
the effect of Lugalvan BNO12 on tin deposition was analyzed. The effects of additive
content，cathode current density，tin ion concentration，methanesulfonic acid concentration，electrode
spacing and electrolyte temperature on power consumption and current efficiency were
studied by electrorefining simulation experiments. The energy consumption was calculated
by recording the cell voltage data at regular intervals. The cathode sample mass was
weighed before and after electrorefining to calculate the cathode current efficiency.
The surface morphology of the cathode tin was observed by macroscopic photography，scanning
electron microscope （SEM），and optical profilometer. The effect of additives on the
surface of the cathode was analyzed by comparing the effects of different additive
concentrations on the surface of the cathode. The composition changes of electrolyte
before and after electrolysis were analyzed by inductively coupled plasma （ICP）. The
changes of peak position and intensity of functional groups before and after electrolyte
electrolysis were analyzed by infrared spectroscopy. The crude tin raw materials and
final products were tested by ICP and compared with the national standard. The results
of electrochemical experiments showed that the addition of Lugalvan BNO12 to MSA electrolyte
could enhance the polarization of the cathode process and inhibit the electrodeposition
of Sn，which was beneficial to inhibit the dendrite growth of Sn during the deposition
process and achieve the densification effect. Through the macroscopic observation
and SEM analysis of the cathode plate，the surface additive Lugalvan BNO12 could reduce
the dendrites and nodules of the cathode tin，and make the cathode tin smooth and dense.
When the concentration of Lugalvan BNO12 was 3 g·L−1，the best dense and smooth cathode tin could be obtained. The optimal process conditions
were as follows：Sn2+ concentration was 100 g·L−1，methanesulfonic acid concentration was 100 g·L−1，Lugalvan BNO12 concentration was 3 g·L−1，cathode current density was 100 A·m−2，electrode spacing was 2 cm，and electrolysis temperature was 35 ℃. Under the optimal
process conditions，the cathode tin was dense and flat without dendrites. The final
product was tested by ICP. The results showed that the purity of the cathode tin could
reach 99.98%，which reached the national standard of 99.95 grade and AA grade tin ingot.
Infrared spectroscopy analysis showed that the peak position and intensity of the
electrolyte did not change，indicating that the MSA system was stable. The methanesulfonic
acid system had excellent stability，and the solution after electrorefining could be
recycled. However，after multiple electrolytic cycles，it was necessary to remove impurity
ions，supplement additives and acid，and Sn2+ in the solution. In future experiments，online detection and adaptive addition of
components in the electrolyte should be increased，expanded production experiments
should be carried out，and the influence of electrolyte circulation on electrorefining
should be explored.
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Aluminum and its alloys find extensive applications in the aerospace，electronic information，and
automobile industries owing to their advantages of lightweight，high specific strength，good
ductility，excellent corrosion resistance，favorable machinability，and moderate price.
However，aluminum and its alloys are highly susceptible to contamination by reacting
with water vapor in the air during the melting and casting process. This reaction
leads to the production of hydrogen and oxide inclusions. To enhance the metallurgical
quality of aluminum alloy melts，flux-based purification treatment technology is commonly
employed for removing hydrogen and oxide inclusions from them. Currently there is
limited research on the strategy of designing flux compositions for purifying aluminum
alloy melts，hence further exploration is required. This study investigated the influence
of rare earth composite flux on melt purification treatment，as-cast microstructure，and
mechanical properties of 6111 aluminum alloy. Firstly，four types of rare earth composite
fluxes (YH-1~YH-4) were developed based on a comprehensive investigation of the thermophysical
parameters of molten salt using differential scanning calorimetry (DSC) and molten
property measurement instrument. The melting points and viscosities of the fluxes
were determined. Secondly，the purification effect，as-cast microstructure，and mechanical
properties of 6111 aluminum alloy were comprehensively evaluated through optical microscope
(OM)，scanning electron microscope (SEM)，and mechanical performance testing. Finally，the
correlation between the purification effect achieved by rare earth composite fluxes
during melt purification treatment and the resulting microstructure and properties
of 6111 aluminum alloy was discussed. The DSC results indicated that the melting points
of four rare earth composite fluxes (YH-1~YH-4) were approximately 570 ℃，whereas the
commercially available flux (ST#) exhibited a melting point around 630 ℃. All four
types of rare earth composite fluxes demonstrated lower melting points compared to
their commercially available counterparts. Furthermore，measurements of molten properties
revealed that the viscosities of all four types of rare earth composite fluxes were
also lower than that of the commercially available flux. Metallographic microstructure
analysis showed more pores and inclusions in untreated as-cast aluminum alloy samples，treated
ones had fewer and smaller ones. Furthermore，statistical analysis of the area fraction
of inclusion indicated that the aluminum alloy samples without flux purification treatment
had the highest recorded value at 2.96%. Meanwhile，the area fraction of inclusions
in the aluminum alloy samples purified by YH-1~YH-4 rare earth composite fluxes and
ST# series fluxes are 1.14%，1.45%，0.75%，0.77%，and 1.13%，respectively. The results
of metallographic microstructure analysis and inclusion area fraction measurement
demonstrated that all four types of rare earth composite fluxes significantly enhanced
the metallurgical quality of the aluminum alloy samples. This improvement can be attributed
to the ability of fluoride compounds present in rare earth composite flux compositions
(such as Na3AlF6 and CaF2) to dissolve and eliminate oxide impurities，or it may be due to a reaction between
rare earth compounds LaF3 and CeF3 in the composite fluxes with the molten aluminum alloy，effectively removing hydrogen
and oxide impurities from the melt. Furthermore，examination of average grain size
revealed that untreated 0# aluminum alloy exhibited the largest average grain size
at approximately 120 μm，while treatment with YH-3 rare earth composite flux resulted
in a significant reduction in average grain size for the treated 3# aluminum alloy
sample to about 65 μm. In summary，grain size，pores，and inclusions had a significant
impact on the mechanical properties of aluminum alloy. After undergoing purification
treatment with rare earth composite fluxes，there was a reduction in grain size as
well as pores and inclusions，consequently improving the hardness，tensile strength，and
elongation of the aluminum alloy. Notably，YH-3 rare earth composite flux exhibited
an optimal purification effect on aluminum melt by reducing inclusion area fraction
from 2.96% to 0.75%，increasing Vickers hardness from HV 61.9 to HV 69.3，lifting elongation
rate from 4.3% to 13.5%，and boosting tensile strength from 95.4 to141.5 MPa.
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