Powder metallurgy is an ideal technique for manufacturing metal matrix composites, owing to its capacity for near-net shape production and minimal material waste. However, a characteristic feature of the aluminum green compacts during the sintering process is the presence of natural oxide films on the surfaces of aluminum powders, which limits the application of aluminum powder metallurgy technology. To address this, we propose a sonication-assisted mixing and liquid metal sintering strategy by which aluminum powder can be easily sintered at the temperature as low as 623 K, two-thirds of the melting point of aluminum. The present investigation demonstrates that the molten gallium enhances metallurgical bonding between the aluminum particles by acting as a “bridge” between adjacent aluminum particles and disrupting the oxide film inevitably existing on the outermost layer of aluminum powder. According to the performance analysis results, when the sintering temperature is as low as two-thirds of the melting point of aluminum, the compressive strength of the Al-5Ga sample increases by 62.5% compared with that of pure aluminum. This innovation will help powder metallurgy researchers to pursue sintering at low-temperature and has a sweeping impact on a wide range of powder metallurgy applications.

The different characteristics of nanoparticles (NPs) are mostly determined by the sintering process. The goal of the current study is to examine how the sintering temperature affects the optical and structural characteristics of Y 2 O 3 NPs made using the sol-gel method. For a competitive study, the synthesized Y 2 O 3 NPs were sintered for three hours at 300, 600, and 900°C. The generated Y 2 O 3 NPs were sintered for three hours at 300, 600, and 900°C in this work. Samples of Y 2 O 3 NPs are designated Y1, Y2, Y3, and Y4, in that order. The cubic structure of Y 2 O 3 NPs is confirmed by XRD examination, which also corresponds to JCPDS card No. 083-0927. For Y1, Y2, Y3, and Y4, the crystallite sizes were determined to be 12.58, 12.24, 12.05, and 09.16 nm, respectively. The optical characteristics, such as energy bandgap fluctuations and light absorption, were investigated using UV-Vis spectroscopy. Usually, the absorbance peak shows up between 230 and 250 nm. For Y1, Y2, Y3, and Y4, the energy band gap was determined to be 4.51, 4.40, 4.31, and 4.19 eV, respectively. The vibrational modes of the Y 2 O 3 NPs are examined, which provides further evidence of phase purity and structural stability. Increased band gap, better crystallinity, and a lower percentage of oxygen atoms all help the material's mechanical and chemical durability as well as its shine, which makes it more suitable for dental ceramic applications.

Although porous aluminum (Al) possesses pore damping characteristics, its damping performance is still unsatisfactory, which limits its further application in vibration reduction and noise reduction. To address this issue, this study utilizes powder metallurgy technology to incorporate graphite (Gr) into porous aluminum. The porous Gr/Al composite prepared by this method has the characteristics of both lightweight and high damping. In porous Gr/Al composites, there exist not only a large number of closed‐cell type pores but also numerous Alp/Alp and Gr/Alp interfaces. The yield strength of the porous Gr/Al composites gradually decreases with increasing ammonium bicarbonate (NH 4 HCO 3 ) and graphite content. Damping tests indicate that both the internal friction (IF) values and the equivalent IF values of the porous Gr/Al composites increase as the ammonium bicarbonate and graphite content rise. At room temperature, the IF value of the Al–10Gr–10N sample is 72% superior to that of the Al–0Gr–10 N sample. At 250 °C, the IF value of the Al–10Gr–10N sample is 99.1% superior to that of the Al–0Gr–10 N sample. The synergistic enhancement effects of the high intrinsic damping characteristics of graphite, pore damping, and interface damping enable the porous Gr/Al composites to have favorable damping performance.

Establishment and control method of digital twin model for refractory alloy smelting and sintering process

Microstructure and Mechanical Properties of Digital Light Processing Printed AISI 316L Stainless Steel: Optimization of Slurry and Sintering Process

Enhancing densification of metakaolin-based geopolymers via the cold sintering process

Toward pharmaceutical selective laser sintering 3D printing - a thermal and temperature-dependent analysis perspective.

Abstract High‐strength α‐Al 2 O 3 porous ceramics are highly valuable for applications in aerospace, chemical catalysis, and related fields due to their exceptional mechanical properties and chemical stability. However, their development has been hindered by performance degradation and high energy consumption associated with traditional high‐temperature sintering methods. While the cold sintering process (CSP) can effectively address these challenges, research on fabricating phase‐pure α‐Al 2 O 3 via CSP remains limited. In this work, α‐Al 2 O 3 porous ceramics were prepared from hydratable alumina by CSP without sintering aids and post‐processing. The hydration characteristics of ρ‐Al 2 O 3 were exploited to optimize the distribution of the transient liquid phase within the system, and the existence of vapor pressure was detected. The influence of CSP parameters on the phase composition, microstructure, and mechanical properties of the samples were systematically investigated. The obtained porous ceramics exhibited a porosity of 42.3%‒34.4%, an average pore size of 463.6 nm, a compressive strength of 89.4‒140.2 MPa, a thermal conductivity ranging from 12.7 to 2.2 W/(m·K) from room temperature to 1200°C, and withstood sintering temperatures up to 1300°C. The study elucidated the nucleation of boehmite and its phase transformation to α‐Al 2 O 3 within the hydrothermal framework, a mechanism supported by direct experimental evidence of the vapor pressure generated in situ. This finding offers significant scientific implications for advancing CSP in the fabrication of α‐Al 2 O 3 porous ceramics.

Background: Cu-based friction materials (CBFMs) exhibit significant application in transportation and mechanical engineering due to their excellent wear resistance, thermal conductivity, and stable tribological performance. Methods: In this study, CBFMs holding a 3D mesh reinforcement structure was prepared under different sintering temperatures and sintering times. The phase, mechanical, and tribological properties were tested, and the wear mechanisms were analyzed. Results: The results showed that with an increase in sintering temperature, compressive strength showed a trend of increasing first and then decreasing, COF showed a decreasing trend first and then an increasing trend, and wear rate showed a decreasing trend that can be attributed to the different strength of the matrix and 3D mesh reinforcement structure at different sintering temperatures. With an increase in sintering time, COF continuously increased and wear rate sustained a decrease. Conclusions: Compared with previous studies, this study revealed the influence mechanism of sintering temperature and sintering time on the comprehensive properties of CBFMs holding a 3D mesh reinforcement structure for the first time. The results can provide data support for the performance improvement of CBFMs holding a 3D mesh reinforcement structure, and lay a theoretical foundation for the further study of powder metallurgy materials.

This study prepared superhard composite consisting of CVDD (Chemical vapor deposition diamond) wrapped by PCD (Polycrystalline diamond) through high-temperature and high-pressure (HPHT) sintering, with Ni-Si-B as the binder for the PCD sintering. The effects of different Ni, Si, and B ratios on the properties and microstructure of the composite materials were investigated through hardness testing, wear ratio testing, and scanning electron microscopy (SEM). The results indicated that Ni and B can provide favorable liquid-phase sintering conditions during the sintering process of polycrystalline diamond, mitigating the detrimental effects associated with the brittleness of silicon carbide (SiC). However, as the Ni content increases, the hardness of the outer PCD layer decreases, and the overall performance of the CVDD/PCD composite declines. The composite exhibited optimal overall performance when the binder content of Si, Ni, B were 9.4wt%, 0.5wt%, 0.1wt%. This study provides a foundation for the research and application of CVDD/PCD composite in hard rock drilling.

Abstract Nanometallic materials have attracted wide research attention in the fabrication of functional devices, including flexible electronics circuits and high-sensitive sensors. Sintering of nanometallic materials is generally thought as an effective technology for the functional manufacturing, and the controllable sintering of nanometallic materials and its major mechanism have long been a challenge. Here, an ultrafast laser processing strategy for Ag nanoparticles (NPs) is achieved by modulating of plasmonic. The excitation mode of plasmon can be designed by laser parameters including polarization with specific crystal size. The atomic-scale ultrafast dynamics is revealed for understanding the sintering process and designing of the sintered structures. The non-equilibrium energy transfer between electron and lattice and dynamic evolution of pressure are proved to the foremost driven-force on the motion of atomic structures. Through research of plasmonic-induced electrical field enhancement and non-uniform deposition of heat and in-situ observation of relative transmittance, mapping from atomic-scale structure to micro behavior is established. Based on plasmonic modulation and processing of Ag NPs, a machine learning combined flexible gesture sensor with high recognition accuracy is displayed. This work expands the knowledge of interaction between laser and nanometallic materials and provides a method for designing functional devices for a wide range of applications.

Sulfur Release Mechanism During Sintering Process of High-Sulfur Kiln Slag Ceramsites

Preparation and properties of LiMgPO4 and its composites using cold sintering process

SOFCs (solid oxide fuel cells) can efficiently convert hydrogen to electricity without CO2 in contrast SOECs (solid oxide electrolysis cells) can synthesize hydrogen from water vapor with high energy conversion. Generally, SOFCs and SOECs have the same cell structure, namely: fuel electrode (support)/ electrolyte layer/ diffusion barrier layer/ air electrode. GDC (Ce0.9Gd0.1O2-δ) is used as a diffusion barrier layer for the roles of (1) preventing reaction between the YSZ (yttria-stabilized zirconia) electrolyte and the air electrode layers, and (2) facilitating the transport of O2- across the cell structure in either operation mode in the temperature range from 600 oC to 800 oC.The GDC interlayer on the YSZ electrolyte is generally prepared using a sintering process at temperatures above 1200 oC, which leads to the formation of undesirable reaction phases at the interface between GDC and YSZ layers. Therefore, it is favorable to prepare a densified GDC layer at lower temperatures for preventing the reaction phase formations between not only YSZ/air electrode interfaces but also YSZ/GDC interfaces. Previously, the effects of employing a dense GDC interlayer, which was deposited by PLD (pulsed laser deposition) under the film preparation conditions of 750 oC and 35 mTorr O2 partial pressure on the SOFC-SOEC properties were investigated [1-3]. In this study, we examined the effects on the SOFC-SOEC performances of GDC interlayers with varied microstructures prepared using the PLD method at a very low deposition temperature and varied O2 partial pressure. The YSZ electrolyte layer was screen-printed on the fuel electrode supports with 60 wt% NiO-40 wt% YSZ composition, and then sintered at 1350 oC for several hours. The GDC interlayer was subsequently deposited using the PLD method at 200 oC and O2 partial pressure between 1 mTorr and 30 mTorr. Then, the air electrode composed of 70 wt% (La0.6Sr0.4)(Co0.2Fe0.8)O3- δ (LSCF) -30 wt% GDC with 10mm in diameter was screen-printed on the GDC interlayer, and then annealed at 950 oC for 1 hour. The electrochemical measurements such as current-voltage curves and impedance spectra were performed using the pseudo four-probe method with humidified H2 supplied to the fuel electrode and dry air to the air electrode.Figure 1 shows the impedance spectra of the single cells with different GDC interlayer microstructures prepared at 200 oC under the pressure of 5 mTorr (Cell B) and 30 mTorr (Cell C), which are compared to the earlier work (our benchmark condition: 35 mTorr at 750 oC, Cell A). The cross-sections of the prepared GDC interlayer are shown in Fig. 1. Cell A and Cell B have a fully dense GDC interlayer, however the GDC grains of Cell C are the smallest among the three and exhibit a columnar microstructure with slightly lower density. The impedance spectra were measured under a slightly SOEC condition (38 mA/cm2) at 650 oC. Cells A and B exhibited a relatively lower total cell resistance of approximately the same value whereas Cell C exhibited a relatively higher value. The ohmic resistance, electrode resistances at lower and higher frequency ranges are separately shown in Fig. 2. The ohmic resistance of Cell C was 0.18 Ωcm2, which was significantly larger than that of Cell A (0.09 Ωcm2) or Cell B (0.10 Ωcm2). Cell A exhibited the smallest ohmic resistance possibly due to its relatively larger GDC grains and consequently fewer grain boundaries. The insufficiently densified columnar structure of Cell C likely influenced the available O2- conduction path. The electrode resistances at lower frequency range were almost the same, so the variation in the GDC microstructures likely does not have any effect on the electrode reaction elements in this frequency range. On the other hand, the higher frequency range showed variations in the electrode resistance values, so it is likely that the GDC microstructures strongly influenced the electrode reaction elements in this frequency range.In the presentation, we will report further details by combining DRT analysis results. Acknowledgements This study is partially based on results obtained from a project, JPNP21022, commissioned by the New Energy and Industrial Technology Development Organization (NEDO).

The increasing power demands of modern miniaturized semiconductor devices necessitate interconnects with high current-carrying capacity and exceptional resistance to thermal stress. Third-generation semiconductors often operate at temperatures reaching up to 300°C, placing stringent requirements on the performance and reliability of interconnect materials. Nanomaterials featuring substantially reduced melting temperatures compared to their bulk counterparts have emerged as promising candidates for on-chip interconnects that enable low-temperature processing and enhanced compatibility with sensitive electronic components.1, 2 In this report, we present a novel two-step synthesis approach to fabricate tin (Sn)-coated nanoporous copper (np-Cu) films, offering a viable pathway for low-temperature sintering.3 Building on our previously reported method for creating compact Cu₃Sn intermetallic (IM) bonds via sintering at temperatures as low as 200°C,4 we further refine this technique by directly utilizing np-CuSn films. This approach holds the potential to enable sintering at even lower temperatures, expanding its applicability for advanced electronic packaging.Our synthetic process involves the electrochemical deposition of a CuSn precursor alloy, followed by an oxidative removal of Sn realized through a partial dealloying step.3 This results in a nanoporous Cu₆Sn₅ IM film with a highly porous, interconnected 3D-structure, ideal for sintering applications. The synthesized IM nanomaterial is subjected to sintering between two Cu surfaces, forming robust, defect-free Cu₃Sn IM joints. The sintering process is carried out in a forming gas atmosphere under a pressure of 20 MPa, with temperatures ranging from 180°C to 300°C. Notably, our method demonstrates the successful formation of densely packed, defect-free electronic joints, highlighting its potential for reliable, high-performance micro-pillar interconnections. References K. Mohan, N. Shahane, R. Liu, V. Smet and A. Antoniou, "A Review of Nanoporous Metals in Interconnects" JOM, 70, 2192 (2018).E. Castillo, J. Zhang and N. Dimitrov, "All-electrochemical synthesis of tunable fine-structured nanoporous copper films" Mrs Bull, 47, 913 (2022).E. Castillo, A. F. Pasha, Z. I. Larson and N. Dimitrov, "New generation copper-based interconnection from nanoporous CuSn alloy film sintered at low temperatures" Mater Adv, 5, 2285 (2024).E. Castillo, M. Njuki, A. F. Pasha and N. Dimitrov, "Copper-Based Nanomaterials for Fine-Pitch Interconnects in Microelectronics" Accounts of Chemical Research, 56, 1384 (2023).

BJ3DP has unique advantages compared to other energy-beam-based additive manufacturing technologies, such as lower residual stress, arising from the lack of heat during the printing process and the uniformity of the sintering process. However, attaining both high density and dimensional precision in metallic materials remains a challenge in BJ3DP. This study presents a systematic investigation into the fabrication of high-melting-point pure chromium (Cr) via binder jetting 3D printing (BJ3DP), with a focus on optimizing the printing parameters and sintering conditions. An orthogonal experiment identified the optimal printing parameters as a layer thickness of 75 μm and a binder saturation of 60%, which resulted in green parts with a relative density of 57.1%—a representative value for BJ3DP processes that demonstrates effective parameter optimization. Subsequently, the green parts were sintered at 1800 °C for 9 h, resulting in a maximum density of 97.35%. The hardness of the as-sintered BJ3DP Cr parts was superior to that of samples produced by conventional levitation melting (184.20 HV vs. 171.20 HV). This work demonstrates that the no-heat printing strategy of BJ3DP effectively mitigates issues related to residual stress and cracking, providing a viable method for producing high-melting-point metallic materials.

ION’s solid-state electrolyte bilayer structure enables anode-free lithium-metal cells that require no heating or compression. ION's cell offers a drop-in replacement for lithium-ion that will redefine the limits of consumer electronics, defense, and EV market applications. In this presentation, ION will share recent progress in cell performance and manufacturability. The architecture-centric design enables competitive cycling and rate performance in the absence of compression and significant volume change. The porous layer of the bilayer structure contains capacity-matched void volume in which the lithium metal plates and strips in a three-dimensional manner. This is achieved even with garnet-type lithium lanthanum zirconium oxide (LLZO) solid-state electrolyte, which typically requires applied pressure. Incorporation of a proprietary anode-free design eliminates the need for lithium metal in the manufacturing process while maintaining high coulombic efficiency. ION’s cells have progressed from small-footprint R&D pouch cells, currently exceeding 1000 cycles (C/3 charge and discharge at 25°C), to multilayer cells with 50x larger capacity produced on ION’s cell pilot line. The multilayer pilot-line cells have exceeded 500 cycles at C/3 charge and discharge at room temperature while retaining >90% of their initial capacity. ION has also made significant advances in manufacturing and scale-up. These include: (1) The development of a novel, curable casting method used for high-throughput production of bilayer LLZO tapes without solvent; (2) optimized batch sintering of LLZO leading to a pilot-scale continuous sintering process; and (3) semi-automated cell pilot line enabling multilayer pouch cells at the Ah scale.

Stable control of sintered ore alkalinity is of great significance for improving furnace efficiency, reducing energy consumption, and minimising carbon emissions. Furthermore, advanced prediction of sintered ore alkalinity is key to achieving stable control. This study innovatively proposes a VMD-EEMD-CNN-LSTM hybrid model that combines the dual signal processing of Variational Mode Decomposition (VMD) and Ensemble Empirical Mode Decomposition (EEMD), along with the local feature extraction of Convolutional Neural Networks (CNN) and the temporal modelling advantages of Long Short-Term Memory networks (LSTM), to achieve multi-scale and precise prediction of sinter bed alkalinity. Validation based on industrial data from a steel plant over five consecutive months (1037 samples) shows that after VMD-EEMD decomposition, the CNN-LSTM model's prediction performance is significantly improved, with the coefficient of determination ( R ²) increasing from 0.73 to 0.97, and the Root Mean Square Error (RMSE) decreasing from 0.017 to 0.0071. Comparative experiments show that under the same decomposition conditions, the proposed model's prediction accuracy ( R ² = 0.97) outperforms CNN (0.95), LSTM (0.95), and BP neural networks (0.954). In the multi-step prediction task, the first-step prediction of the model achieves an R ² of 0.97, and the third-step prediction RMSE is 0.849, demonstrating better stability compared to VMD-EEMD-CNN (0.83), VMD-EEMD-LSTM (0.78), VMD-EEMD-RNN (0.84), VMD-EEMD-BP (0.79), and VMD-EEMD-SVM (0.82). The research findings provide a reliable theoretical foundation and technical pathway for intelligent control of the sintering process.

Protonic solid oxide electrolysis cells (P-SOECs) represent a promising technology for efficient hydrogen production by leveraging their low activation energy for proton conduction to achieve high water-splitting performance at intermediate temperatures. Protonic ceramic electrolytes are critical components that determine the performance and efficiency of P-SOECs. Extensive research has been conducted to develop and design high-performance protonic ceramics as electrolyte materials. Among these, Ba(Ce,Zr)O3 perovskite oxides doped with Yttrium (Y) and/or Ytterbium (Yb) have successfully demonstrated a balance between conductivity and chemical stability, as well as compatibility with high-temperature manufacturing processes. However, the stability of Ba(Ce,Zr)O3-based materials remains uncertain after repeated heat treatments during the preparation process. High-temperature sintering processes are crucial for achieving the desired densification and microstructural properties but can lead to issues such as oversintering, Ni diffusion, and phase instability. Additionally, lower temperature refiring processes, which are employed to enhance the bonding between the oxygen electrode and electrolyte, can induce unwanted precipitations and secondary phase formations that detract from proton conductivity. Herein, we demonstrate the influence of processing parameters, including both high-temperature sintering and lower temperature refiring, on the stability of electrolyte materials and the electrochemical performance of P-SOECs.

Abstract Al 2 TiO 5 –mullite material was produced through the sintering process using Algerian natural raw materials. The selected raw materials included kaolin KT (45 wt.%), potassic feldspar (30 wt.%), and quartz (25 wt.%), with TiO 2 nanoparticles added at concentrations of 5 and 10 wt.%. The mixture was milled for 8 h at room temperature in a high-energy planetary ball mill under an argon atmosphere. After milling, the powders were pressed into pellets and then sintered for 2 h at a temperature of 1,200 °C in air. The effect of TiO 2 nanoparticle addition on the physical and structural properties of the porcelain was analyzed using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy, as well as bulk density and shrinkage measurements. The sintered ceramics primarily showed mullite and quartz. With 5 wt.% TiO 2 , aluminate titanate (Al 2 TiO 5 ) began to form in addition to the existing phases, while rutile was observed as an unreacted phase. Increasing TiO 2 content to 10 wt.% led to a higher volume fraction of Al 2 TiO 5 and a reduction in mullite content. The overall densification of the ceramics improved with the addition of TiO 2 , enhancing physical and microstructural properties.