Solid-liquid Transition Research Articles

Multi-deformable interpenetrating network thermosensitive hydrogel fluorescent device for real-time and visual detection of nitrite

Functionalized thermosensitive hydrogel materials exhibit excellent properties for the fabrication of sensing devices that enable real-time visual detection of food safety duo to their good plasticity and powerful loading capacity. Here, a ratiometric fluorescent device based on an interpenetrating network (IPN) thermosensitive hydrogel was designed to embed functionalized Au nanoclusters (Au NCs) and Blue Carbon dots (BCDs) composites in a multi-network structure to build a sensitive hazardous material nitrite (NO2-) chemsensor. The hydrogel was utilized poloxamer 407 (P407), lignin and cellulose to form stable IPN structure, which resulted in complementation and synergy, thereby strengthening its porous network structure. The combination of fluorescent nanoprobes with the porous network structure has the potential to enhance stable fluorescence signals and improve sensing sensitivity. Moreover, the thermosensitive liquid-solid transition characteristics of the hydrogel facilitate its preparation into diverse sensing devices following curing at room temperature. The hydrogel device, when combined with a smartphone system, converted image information into data information, thereby enabling the accurate quantification of NO2- with a detection limit of 9.38 nM in 2 s. The designed multi-functional hydrogel device is capable of real-time differentiation of NO2- dosage with the naked eye, offering a high-contrast, rapid-response sensing methodology for visual assessment of food freshness. This research contributes to the expansion of hydrogel materials applications and the detection of hazardous materials in food safety.

Numerical Investigation of the Effects of Process Parameters on Temperature Distribution and Cladding-Layer Height in Laser Cladding

To delve into the effects of process parameters on temperature distribution and cladding-layer height in laser cladding, as well as the interaction between these two aspects, a thermal–fluid coupling numerical model was established considering process parameters (i.e., laser power and scanning velocity), the Marangoni effect, molten pool dynamics, and solid–liquid transition. The numerical findings indicate that the Marangoni effect is the main factor for the growth of the cladding layer. The cladding-layer height increasingly influences heat-transfer efficiency as it develops. Higher laser power or lower scanning velocity, or a combination of both, can lead to higher cladding temperatures and greater cladding-layer height. Under the combination of laser power of 1750 W and scanning velocity of 4 mm/s, the numerical simulation predicts a cladding-layer height of 1.12 mm, which closely aligns with the experimentally determined height of 1.11 mm. Additionally, the comprehensive error being below 5% demonstrates the model’s considerable instructional value for practical applications.

Regulated Interfacial Proton and Water Activity Enhances Mn2+/MnO2 Platform Voltage and Energy Efficiency

Aqueous zinc battery (AZB) is one of the most promising energy storage systems for large-scale applications due to its high safety, low cost, and environmental friendliness. To match the high capacity of zinc metal (~820 mAh g-1), various cathode materials, such as oxides, open structure analogues, chalcogens, and halogens, have been explored for AZBs. Among them, manganese dioxide (MnO2) has been considered to be one of the most attractive candidates due to its high capacity (~308 mAh g-1 for one-electron transfer) and adequate redox potential (~0.70 V vs. SHE). Recently, the MnO2 dissolution/deposition charge storage mechanism has been demonstrated to further increase the voltage and capacity of Mn-based AZBs. The dissolution/deposition (Mn2+/MnO2) is a two-electron transfer process, which doubles the theoretical capacity of MnO2 cathode to ~616 mAh g-1 and considerably increases the redox potential (~1.229 V vs. SHE). The charge storage via the dissolution/deposition mechanism pushes the aqueous-based energy density even higher, to over 1000 Wh kg-1.However, this charge storage mechanism involves liquid-solid transition, as well as the thermodynamics and kinetics of this reaction are highly dependent on the acidity and interfacial environment. Yet, the opposite effect of interfacial H+ on the dissolution/deposition processes and the role of interfacial H2O are rarely discussed. Here we introduce tetrafluoroborate anion (BF4 -) into the sulfate-based electrolyte to regulate the interfacial H+ and H2O activity. First, BF4 - hydrolysis increases the electrolyte’s acidity, promoting MnO2 dissolution. Second, BF4 - forms an H-bond network with interfacial H2O that assists H+ diffusion while retaining sufficient H2O supply to facilitate MnO2 deposition. As a result, the cathode-free Zn//MnO2 electrolytic cell achieves a high plateau of ~1.92 V and energy efficiency of ~84.23 % in the BF4 - containing electrolyte. Significantly, the cell delivers 1000 cycles at 1 C with ~100 % Coulombic efficiency and a high energy efficiency retention of 93.65 %. Our findings disclose a new strategy to promote Mn2+/MnO2 platform voltage and energy efficiency for future large-scale energy storage systems.

Three-dimensional solidification modeling of various materials using the lattice Boltzmann method with an explicit enthalpy equation.

Based on the mesoscopic scale, the lattice Boltzmann method (LBM) with an enthalpy-based model represented in the form of distribution functions is widely used in the liquid-solid phase transition process of energy storage materials due to its direct and relatively accurate characterization of the presence of latent heat of solidification. However, since the enthalpy distribution function itself contains the physical properties of the material, these properties are transferred along with the enthalpy distribution function during the streaming process. This leads to deviations between the enthalpy-based model when simulating the phase transition process of different materials mixed and the actual process. To address this issue, in this paper, we construct an enthalpy-based model for different types of materials. For multiple materials, various forms of enthalpy distribution functions are employed. This method still uses the form of enthalpy distribution functions for collisions and streaming processes among the same type of substance, while for heat transfer between different materials, it avoids the direct transfer of enthalpy distribution functions and instead applies a source term to the enthalpy distribution functions, characterizing the heat transfer between different materials through the energy change before and after mixing based on the temperature. To verify the accuracy of the method proposed in this paper, a detailed solidification model for two different materials is constructed using the example of water droplets solidifying in air, and the results are compared with experimental outcomes. The results of the simulation show that the model constructed in this paper is largely in line with the actual process.

Solid–liquid transition in a skyrmion matter

We report Monte-Carlo studies of the orientational order and melting of a 2D skyrmion lattice containing more than one million spins. Two models have been investigated, a microscopic model of lattice spins with Dzyaloshinskii–Moryia interaction that possesses skyrmions, and the model in which skyrmions are treated as point particles with repulsive interaction derived from a spin model. They produce similar results. The skyrmion lattice exhibits a sharp one-step transition between solid and liquid phases on temperature and the magnetic field. This solid–liquid transition is characterized by the kink in the magnetization. The field-temperature phase diagram is computed. We show that the application of the field gradient to a 2D system of skyrmions produces a solid–liquid interface that must be possible to observe in experiments.

Effect of Ni addition on the crystallization behaviors of Cr-Co alloy

Optimizing the crystallization kinetics of Cr-Co alloys through doping is of practical significance to their industrial applications. By employing molecular dynamics (MD) simulations, this study investigates the effect of Ni concentration on the solidification process of Cr30Co70-xNix (x=0, 10, 20, 30, 40) alloys, focusing on crystallization behavior during quenching and microstructural characterization. The evolution of potential energy indicates that higher Ni concentrations promote crystallization, resulting in a lower liquid-solid transition temperature and enhanced relaxation. However, Ni doping does not alter the preference for chemical ordering, with Cr-Co bonding predominant across all the compositions. Microstructural analysis reveals a shift towards fcc-dominant ternary alloys with increased Ni content. Furthermore, Ni addition impacts defect distribution, notably reducing "other" types of defects in the Cr-Co binary alloy. These findings provide a quantitative reference for adjusting the crystallization behavior of Cr-Co alloys through doping, with implications for their design, manufacturing, and utilization.

Solid–Liquid Phase Equilibrium of the n-Nonane + n-Undecane System for Low-Temperature Thermal Energy Storage

The current article presents an exploration of the solid–liquid phase diagram for a binary system comprising n-alkanes with an odd number of carbon atoms, specifically n-nonane (n-C9) and n-undecane (n-C11). This binary system exhibits promising characteristics for application as a phase change material (PCM) in low-temperature thermal energy storage (TES), due to the fusion temperatures of the individual components, thereby motivating an in-depth investigation of the solid–liquid phase diagram of their mixtures. The n-nonane (n-C9) + n-undecane (n-C11) solid–liquid phase equilibrium study herein reported includes the construction of the phase diagram using Differential Scanning Calorimetry (DSC) data, complemented with Hot–Stage Microscopy (HSM) and low-temperature Raman Spectroscopy results. From the DSC analysis, both the temperature and the enthalpy of solid–solid and solid–liquid transitions were obtained. The binary system n-C9 + n-C11 has evidenced a congruent melting solid solution at low temperatures. In particular, the blend with a molar composition xundecane = 0.10 shows to be a congruent melting solid solution with a melting point at 215.84 K and an enthalpy of fusion of 13.6 kJ·mol–1. For this reason, this system has confirmed the initial signs to be a candidate with good potential to be applied as a PCM in low-temperature TES applications. This work aims not only to contribute to gather information on the solid–liquid phase equilibrium on the system n-C9 + n-C11, which presently are not available in the literature, but especially to obtain essential and practical information on the possibility to use this system as PCM at low temperatures. The solid–liquid phase diagram of the system n-C9 + n-C11 is being published for the first time, as far as the authors are aware.

A high-performance aqueous Eu/Ce redox flow battery for large-scale energy storage application

We report the performance of an all-rare earth redox flow battery with Eu2+/Eu3+ as anolyte and Ce3+/Ce4+ as catholyte for the first time, which can be used for large-scale energy storage application. The cell reaction of Eu/Ce flow battery gives a standard voltage of 1.90 V, which is about 1.5 times that of the all-vanadium flow battery (1.26 V). Large standard voltage is conducive to the improvement of battery energy density and power density. The Eu2+/Eu3+electrode reaction in a NaCl solution on platinum electrode was investigated detailedly using cyclic voltammetry, linear sweep voltammetry, tafel plot and chronoamperometry. Unlike zinc-cerium flow battery, the active species of Eu/Ce flow battery are always present in the electrolyte, and no liquid-solid phase transition occurs. Thus, Eu/Ce flow battery is free of the problems associated with dendrite growth and theoretically have a longer cycle lifetime. The negative electrolyte is very sensitive to oxygen and can directly cause battery failure if exposed to air. The average energy efficiency of Eu/Ce flow battery exposed to air is only 22.0 %. However, the average energy efficiency of Eu/Ce flow battery stripped of oxygen reaches 82.7 % at 25 mA/cm2. Preliminary experimental studies have shown that Eu/Ce flow batteries are a promising method for large-scale energy storage.

Highly dispersed Ag quantum dots anchored on palmitic acid/ graphitic carbon nitride composite phase change materials for enhanced photo-thermal storage

Phase change materials (PCM) have attracted much attention in the field of thermal energy storage because of exceptional heat storage capacity, stable operating temperature, and recyclability. However, organic phase change materials, represented by palmitic acid (PA), are limited by inherent leakage problem, unsatisfactory thermal responsiveness and inefficient photo-thermal storage capacity, which severely hamper the development of PCMs technology. As a means of addressing these challenges, we developed one novel support material with 2D/0D structure for palmitic acid via thermal polymerization, specifically, in which highly dispersed Ag quantum dots (Ag QDs) was firmly anchored on graphitic carbon nitride (g-C3N4). PA was further infiltrated into the layered structure of nanoporous g-C3N4/Ag QDs to successfully synthesize novel shape-stabilized PA/g-C3N4/Ag QDs composite phase change materials (CPCM). On the one hand, benefiting from the tightly stacked porous structure of g-C3N4/Ag QDs, PA is effectively encapsulated to avoid leakage problem during the solid-liquid transition with a superior adsorption capacity up to 65 %. On the other hand, the combination of g-C3N4 and Ag QDs in PA/g-C3N4/Ag QDs CPCM demonstrated a synergistic effect resulting in faster heat transfer capability and more efficient solar energy capture capability compared to pure PA, which is capable of dual utilization of heat and solar energy. The newly developed PA/g-C3N4/Ag QDs CPCM features a high melting latent heat and an appropriate phase change temperature, which are 128.35 J/g and 61.92 °C, respectively. The corresponding solidification enthalpy and temperature are 121.70 J/g and 60.02 °C. The photo-thermal conversion efficiency of the material is improved to 78.6 %, facilitating a rapid capture and storage of solar energy. Furthermore, through the optimization of the preparation process, Ag QDs are densely anchored on the surface of g-C3N4, which retains the excellent properties of metallic silver while eliminates the metal agglomeration phenomenon after repeated utilization of CPCMs. PA/g-C3N4/Ag QDs CPCM is proved to be extremely recyclable and thermally stable after massive thermal cycles. This innovative and operational encapsulation modified method significantly optimizes the practicality of phase change materials. The obtained shape-stabilized PA/g-C3N4/Ag QDs CPCM is more versatile, and its unique comprehensive properties can provide high-quality materials for photo-thermal storage systems.

Photoisomerization Induced Solid–Liquid Transition Polymers Enabling Light Regulated Intelligent Lubrication Behavior

Photoisomerization Induced Solid–Liquid Transition Polymers Enabling Light Regulated Intelligent Lubrication Behavior

Nontrivial effects of geometric and charge defects on one-dimensional confined water

Water confined within nanochannels with specific functionalities serves as the foundation for a variety of emerging nanofluidic applications. However, the structure and dynamics of the confined liquid are susceptibly influenced by practically hard-to-avoid defects, yet knowledge of this fact remains largely unexplored. Here, using extensive molecular dynamics simulations, we elucidate the significant influence of geometric and charge defects on one-dimensional confined water. We show that the two types of defects can both reshape the water density distribution by constraining the translocation of water molecules along the circumferential direction. In addition to structural alterations, collective translocation and rotation of water slabs arise during transportation under external pressure. Below the temperature threshold marking the initiation of liquid-solid transition, the geometric defect retards water diffusion through a pinning effect, while the charge defect induces an anti-freezing effect. The latter is attributed to the electrostatic interaction between the charge defect and water molecules that hinders the formation of a stable hydrogen bond network by disrupting molecular dipole orientation. Consequently, this behavior results in a reduction in the number and lifetime of hydrogen bonds within the phase transition interval. The distinct roles of the two types of defects could be utilized to control the structure and dynamics of confined liquids that may result in distinct functionalities for nanofluidic applications.

20.2% Efficiency Organic Photovoltaics Employing a π-Extension Quinoxaline-Based Acceptor with Ordered Arrangement.

Organic solar cells, as a cutting-edge sustainable renewable energy technology, possess a myriad of potential applications, while the bottleneck problem of less than 20% efficiency limits the further development. Simultaneously achieving an ordered molecular arrangement, appropriate crystalline domain size, and reduced nonradiative recombination poses a significant challenge and is pivotal for overcoming efficiency limitations. This study employs a dual strategy involving the development of a novel acceptor and ternary blending to address this challenge. A novel non-fullerene acceptor, SMA, characterized by a highly ordered arrangement and high lowest unoccupied molecular orbital energy level, is synthesized. By incorporating SMA as a guest acceptor in the PM6:BTP-eC9 system, it is observed that SMA staggered the liquid-solid transition of donor and acceptor, facilitating acceptor crystallization and ordering while maintaining a suitable domain size. Furthermore, SMA optimized the vertical morphology and reduced bimolecular recombination. As a result, the ternary device achieved a champion efficiency of 20.22%, accompanied by increased voltage, short-circuit current density, and fill factor. Notably, a stabilized efficiency of 18.42% is attained for flexible devices. This study underscores the significant potential of a synergistic approach integrating acceptor material innovation and ternary blending techniques for optimizing bulk heterojunction morphology and photovoltaic performance.

Performance evaluation of combined passive/active thermal charge/discharge latent heat tank with stabilized-solid-liquid storage material for intermediate thermal storage system

This study proposes a new model operation for an intermediate thermal storage (ITS) tank for solar water heater system. It combines passive-charge active-discharge (PCAD) in a single storage tank, potentially reducing the number of components of the system and improving the net energy balance. The charge process is done by heating the storage material using an electric heater, which is also suitable for direct photovoltaic heating. The temperature profile of stabilized storage material in this stage shows a close plateau line in the solid-liquid transition, indicating a steady phase transition takes place. It minimizes the temperature deviation between the solid/liquid region, which is advantageous for determining the operation protocol. For the discharge process, the working fluid circulates from the mantle side and continues to the inner side of the tank, resulting in two-consecutive heating. It allows the fluid to harness the stored heat up to 72.8%. It is also achieved by the stabilized storage material, which has a better solidification mechanism. Thus, the proposed PCAD tank is able to meet the criteria of an ITS tank, which requires energy exchange during the charge/discharge stage. The finding demonstrates that a simplification of the ITS tank is achievable. The implication of the finding can be used as a fundamental basis for developing new solar water heating systems, including for direct charge operation using photovoltaic-heating systems where the heat is taken as alternative energy storage instead of electricity.

Co-solvent and additive joint engineering enable long-life and wide-temperature Zn metal battery

The dendrite growth and interfacial side reactions pose significant threaten to the practical applications of aqueous zinc metal batteries (AZMBs), especially at subzero temperature environments. To this end, co-solvent and additive joint engineering is proposed to design hybrid electrolyte, which consists of a mixture of 1,2-propanediol (1,2-PG) solvent and H2O with trace amounts of 18-crown-6 molecules, for constructing stable wide-temperature AZMBs. Notably, the 18-crown-6 and 1,2-PG molecules can both disturb the original hydrogen-bond network of H2O molecules. Interestingly, the 18-crown-6 molecules predominantly tends to absorb on the Zn anode surface and form favorable organic-inorganic hybrid SEI layer to regulate Zn deposition behaviors. The 1,2-PG molecules are responsible for reconstructing the solvation structure of Zn2+ and lowering the solid-liquid transition temperature of aqueous electrolyte, suppressing the H2O-induced side reactions and improving the antifreezing capability of electrolyte. Furthermore, the hybrid electrolyte induces the preferential Zn(002) plane deposition under the low temperature environments due to the synergistic effect of 18-crown-6 and 1,2-PG molecules, enhancing the Zn2+ transport and deposition kinetics. Consequently, the hybrid electrolyte endows the assembled cells with enhanced cycling lifespan and reversibility within the wide temperature range from -50 to 25 °C, expanding the application range of AZMBs.

Multiscale Porous Architecture Consisting of Graphene Aerogels and Metastructures Enabling Robust Thermal and Mechanical Functionalities of Phase Change Materials

AbstractPassive thermal energy storage systems using phase change materials (PCMs) are promising for resolving temporal‐spatial overheating issues from small‐ to large‐scale platforms, yet their poor shape stability due to solid–liquid transition incurs PCM leakage and weak resistance against mechanical disturbance, limiting practical applications. While foam‐stable templates for PCMs have shown complement, they reveal massive leakage and collapse of liquefied PCMs under external loads or impacts. Herein, a multiscale porous architecture consisting of graphene aerogels (GAs) and meta structures enabling robust thermal‐mechanical functionalities of PCMs (3D‐MPGA) toward sustainable phase change thermal energy storage composites is reported. 3D‐printed mechanical metamaterials employing octet‐truss cells provide supportive strength and directionally‐assisted leakage reduction, while GAs serve as porous templates with surface‐interfacial contacts, thereby fixing paraffin wax as PCM inside their nano/micropores. The 3D‐MPGA shows intrinsic thermal characteristics of bulk PCMs, and improved thermal‐mechanical‐chemical stability, confirmed by long‐term heating‐cooling cycle tests over 10 h. Moreover, it exhibits highly reinforced strength (200–5000%) within a low density across ambient and melting temperatures, and maintains original shapes in the liquefied PCMs without severe leakage, against external loads. This work inspires rational strategies for advancing robust thermal‐mechanical functionalities for PCM‐based thermal energy storage systems.

Effect of Marangoni flow during the solidification of a Fe-0.82wt.%C steel alloy

A two-phase Mixture model is proposed to simulate the liquid-solid phase transition of a Fe-0.82wt%C steel alloy under the effect of Marangoni flow. This model simplifies computations by solving a single momentum and enthalpy equation for the mixture phase using a three-dimensional finite volume method. The simulation involves solidifying a rectangular ingot (100 × 10 × 100 mm3) from the cold bottom surface towards the hot-free surface at the top. To facilitate heat exchange with the surrounding environment, a high heat transfer coefficient of h = 600 W/m2/K was applied on the bottom surface to establish an upward solidification direction. However, a lower heat transfer coefficient of 20 W/m2/K was applied on the top free surface, which was considered flat. This study aims to examine the effect of Marangoni flow generated by surface tension on flow and segregation patterns. The results show that the Marangoni flow emerges at the free surface and penetrates into the liquid depth, leading to the formation of hexagonal patterns along the liquid thickness. Upon full solidification, macro-segregation also exhibits hexagonal structures, mirroring the stationary hexagonal shapes generated by Marangoni flow.

Thermosensitive injectable polysaccharide-based hydrogels: Gelation mechanisms, synthetic strategies, biomedical applications, and challenges

In recent years, thermosensitive polysaccharide-based injectable hydrogels have gained increasing attention in biomedical applications, including wound healing, drug delivery, and cartilage repair. These hydrogels have favorable biocompatibility, biodegradability, and tunable physical and chemical properties. Thermosensitive polysaccharide-based injectable hydrogels are a class of intelligent soft matter material. They can undergo a reversible liquid-solid transition when exposed to temperature stimuli. Therefore, their precursor solutions can be accurately inserted into target sites with irregular geometries in a minimally invasive way and then transformed into gels in situ by the organism’s temperature stimulation to deliver biologically active molecules. This review summarizes the recent developments of thermosensitive injectable polysaccharide-based hydrogels. The focus is on the mechanism of sol-gel phase transition, as well as the design and preparation of thermosensitive polysaccharides and their applications in biomedical fields. In addition, the outlook of the challenges in biomedical applications is provided at the end of the paper.

High transition kinetics enabling high Zn utilization for high-capacity and long-lifespan nickel-zinc battery

Aqueous nickel-zinc (Ni-Zn) battery is one promising grid energy storage device owing to its high theoretical energy density, high safety and low cost. However, the large-scale commercialization of Ni-Zn battery is significantly hindered by its low practical energy density and poor cycle lifespan caused by the low reversibility and transition kinetics between the metallic Zn and ZnO with low Zn utilization. To address these issues, a type of hierarchical porous Indium-doping ZnO micro-bowls (In-ZnO) is constructed through an in-situ chemical corrosion strategy. The abundant voids and pores facilitate the ionic transport, and simultaneously accommodate the volumetric expansion during the electrochemical transition between metallic Zn and ZnO. Density functional theory calculations further reveal that In-ZnO achieves the enhanced electrical/ionic conductivity and improved adsorption to OH–, accelerating the solid–liquid transitions of Zn-Zn(OH)42- and Zn(OH)42--ZnO, as well as the solid–solid transition of Zn-ZnO. Simultaneously, the Indium-doping inhibits the hydrogen evolution and passivation. Ascribed to the synergetic effect of the hierarchical porous structure and Indium-doping, the In-ZnO electrode demonstrates ultra-stable capacity retention of 98.6% over 1000 cycles at 9 A g-1 under 92.3% Zn utilization, and high capacity of 590.2 mAh g-1 even at high current density of 36 A g-1.

Percolation to jamming in polymethylvinylsiloxane/silica nanocomposites

Researchers have conducted extensive experimental and theoretical studies on the jamming transition of colloidal and granular suspensions, but the existence and characteristics of jamming transition in nanoparticle-filled polymers remain elusive. In this work, two kinds of polymethylvinylsiloxane/silica nanocomposites were studied. A liquid-solid transition was found at the silica volume fraction of about 5 vol%, corresponding to the percolation of particle agglomerates. At higher silica content (about 10 vol%), a solid-solid transition was found in yield stress, equilibrium modulus, and the contact stress between agglomerates. The characteristic length of the particle network and inter-molecular distance also showed a transition at this transition. This transition corresponds to the simultaneous jamming of particles inside agglomerates and between agglomerates. This bi-level jamming behavior is distinct from the well-known jamming behavior in soft or hard particulate suspensions. Moreover, the dependence of the yield stress and equilibrium modulus on the distance to the jamming concentration differs from the simulations using simple interaction models like harmonic and Hertzian models. It implies that the interfacial viscoelastic layer may offer additional attractive and adhesive interactions between nanoparticles, which is critical in the jamming of polymer nanocomposites.

Viscosity and structure studies of iron-based quaternary melts: The effect of P

This study systematically investigates the underlying principles and mechanisms governing viscosity across the entire range for the Fe-4.5C-0.1Ti-xP (in wt.%) melts. The viscosity profile exhibits distinct variations in different phases. In the solid–liquid transition region, the primary determinant of viscosity is the presence of solid phase particles, while in the region characterized by liquid phase, the primary influencing factor is the number of clusters. Notably, the impact of P content demonstrates a contrasting effect on low-temperature solid phase precipitation and high-temperature liquid phase structure. During the low-temperature solid phase precipitation stage, an increase in P content serves as a catalyst for graphite precipitation, resulting in an increase in system viscosity and, by extension, impacting an increase in system viscosity. In contrast, within the high-temperature liquid phase, the interaction of P with iron (Fe) results in the breakdown of mid-range clusters in the original system, leading to the formation of smaller clusters with a reduced overall cluster volume. Consequently, an increase in P content is associated with a decrease in viscosity. These findings provide a nuanced understanding of the interplay between P content and viscosity throughout different phases of the melt.