Infiltration Technology Research Articles

New strategy for fusion infiltration processed Cu/MoCu/Cu composites

Existing thermal management materials suffer from high thermal resistance, low strength and many interfacial defects. To solve these problems, in this study, Cu/Mo70Cu30/Cu (or CPC) composite was prepared by using fusion infiltration technology with Cu wrapped Mo (Cu@Mo) composite powder as the raw material, and CPC samples with a thickness of 1.8 mm and three layer thickness ratio of 1:4:1 were further processed using a jacket rolling process. Results showed that using the Cu@Mo composite powders and following melting and infiltration processes not only changed the interfacial homogeneous structures of composites from mechanical bonding to metallurgical bonding, but also created good thermal conductivity channels of Cu in the MoCu core structure. The large rolling rate of plastic deformation created a 0.7 μm wide transition zone at the Cu/MoCu interface, resulting in efficient heat and stress transfer between two phases of molybdenum and copper. The composites showed a high densification rate larger than 98 %, a thermal conductivity of 270.8 W/(m·K), a coefficient of thermal expansion of 7.96 × 10−6/K at 30 °C, and a tensile strength of up to 542.5 MPa.

Antimicrobial, remineralization, and infiltration: advanced strategies for interrupting dental caries

Abstract Dental caries, driven by plaque biofilm, poses a major oral health challenge due to imbalance in mineralization and demineralization. The primary objective in caries management is to maintain biofilm homeostasis while facilitating the repair and regeneration of dental hard tissues, thus restoring both structural integrity and functionality of affected teeth. Though antimicrobial and remineralization approaches haven shown promise, their standalone utilization without concurrent bacterial control or rebalancing lacks an integrated strategy to effectively arrest caries progression. Furthermore, according to the principles of minimally invasive dentistry, treatment materials should exhibit high permeability to ensure optimal sealing of demineralized tooth surfaces. The concept of interrupting dental caries (IDC) has emerged as a holistic approach, drawing upon extensive research encompassing three pivotal techniques: antibacterial strategies, remineralization therapies, and infiltration mechanisms, all of which are indispensable components in combating the progression of dental caries. In this review, we provide a comprehensive overview of the mechanisms and applications of antibacterial, remineralization, and infiltration technologies within the context of caries management. Additionally, we summarize advanced materials that align with the IDC concept, aiming to offer valuable insights for designing next-generation materials adept at preventing or halting caries progression efficiently.

Improvement on interfacial properties of CuW and CuCr bimetallic materials with high-entropy alloy interlayers via infiltration method

Abstract In order to achieve metallurgical bonding in the form of solid solution at the Cu/W interface and avoid the formation of intermetallic compounds, the novel high entropy alloys (HEAs) were designed on the basis of the mature high entropy alloy criteria. The CuCrCoFeNi x Ti high entropy alloys interlayers were applied to weld the CuW and CuCr bimetals by sintering–infiltration technology. Scanning electron microscope, energy dispersive spectrometry, and X-ray diffraction were used to explore the interfacial microstructure evolutions and strengthening mechanism of CuW/CuCr joints with applied HEA interlayers. The interfacial characterization results show that HEAs were diffused and dissolved into bimetallic materials, and a diffusion solution layer of 2–3 μm thickness was formed at the Cu/W phase interface, and there is no new phase generated at the CuW/CuCr interface. When CuCrCoFeNi1.5Ti interlayer was infiltrated into the CuW/CuCr interface, the electrical conductivity of CuCr side is 71.6%IACS, and the interfacial tensile strength reaches 484.5 MPa. Compared with the CuW/CuCr integral material without interlayer, the interfacial bonding strength is increased by 43.1%. And the SEM fracture morphology presents a larger amount of cleavage fractures of W particles. It indicates the appropriate solid solution layer on edge of W skeletons formed at the Cu/W phases interface. The Cu/W phase interface is strengthened, and it can effectively transfer and disperse the external load. Tungsten phase with higher elastic modulus endures a large amount of load, resulting in enhancing the CuW/CuCr interfacial bonding strength. When CuCrCoFeNi2Ti high entropy alloy interlayer was applied, the W skeleton near the CuW/CuCr interface was eroded, the imperfect W skeleton cannot withstand the tensile load effectively, resulting in decrease in the CuW/CuCr interfacial bonding strength. In the interfacial fracture, appears some fragmentations of W particles, and fewer W particles occur at the cleavage fracture.

Improving thermal conductivity of Al/SiC composites by post-oxidization of reaction-bonded silicon carbide preforms

High thermal conductivity aluminium-based silicon carbide (Al/SiC) composites were successfully fabricated through post-oxidization of reaction-bonded silicon carbide preforms (RS preforms), utilizing vacuum pressure infiltration technology. The study investigated the regulation of interfacial reactions in conventional sintering and reaction sintering. Conventional sintering introduced a large amount of SiO2, which negatively impacted the thermal conductivity of the Al/SiC composite, but the reaction sintering not. The proposed post-oxidization treatment of RS preforms effectively removed residual carbon from the SiC particle surfaces, thereby forestalling the formation of Al4C3. Furthermore, the post-oxidization treatment effectively formed lightweight SiO2 deposits onto the surface of SiC particles, improving Al-SiC interfacial wettability and reducing thermal resistance, thereby enhancing composite thermal conductivity. Notably, the thermal conductivity of the post-oxidized sample exhibited an increase of 6.5% compared to the untreated sample. The study also evaluated the impact of particle size distribution on volume fraction and thermal properties. The optimized Al/SiC composites yielded thermal conductivity, coefficient of thermal expansion, bending strength, and Young’s modulus values of 237.3 W/m K, 8.5 × 10−6/°C, 325 MPa, and 75.9 GPa, respectively.

Simultaneously increasing the mechanical properties and corrosion resistance of B4C/Al composites via forming “TiO2–Al” interfacial layer

In this work, we use a simple and efficient method to introduce “TiO2–Al” interfacial layers between the B4C particles and aluminium (Al) matrix in TiO2@B4C/Al composites by combining the ball milling dispersion process with the pressure infiltration technology. It is anticipated that it would improve the mechanical properties and corrosion resistance. The work demonstrates that the coefficient of thermal expansion (CTE) of the “TiO2–Al” interfacial layer is between those of the matrix and the reinforcement. Thus, it relieves the residual stresses in the composites. Furthermore, the low residual stress of the composites achieved by introducing the “TiO2–Al” interfacial layer results in delayed failure and the low corrosion tendency. The composites containing “TiO2–Al” interfacial layers show remarkable bending properties (a strength of 668.6 MPa) and good corrosion resistance (a low corrosion current density of 6.81 μA cm−2). Thus, the TiO2@B4C/Al composites exhibit remarkable mechanical properties and corrosion resistance compared with the composites reported in the literature.

Improved broadband design of SiC/MWCNT absorbing materials through synergistic regulation of heterointerface structure and triple periodic minimal surface meta-structure

SiC/multi-walled carbon nanotube (MWCNT) composites are considered to be promising materials for high-temperature electromagnetic wave (EMW) absorption due to their strong thermal stability and tunable dielectric properties. However, the EMW absorption performance of these composites is limited by poor impedance matching. This study proposes a novel multiscale structure synergistic regulation approach to enhance EMW absorption performance, which involves constructing a heterointerface structure and a triple periodic minimal surface (TPMS) meta-structure. The addition of a SiO2 shell as an impedance layer to the SiC/MWCNT core to improve the intrinsic impedance. Meanwhile, the heterointerface between the core-shell structure leads to multiple interface polarization, significantly enhancing EMW energy dissipation. Consequently, the effective absorption bandwidth (EAB) of SiO2–SiC/MWCNT composites increased from 0.88 to 4.56 GHz. Furthermore, a TPMS meta-structure, fabricated by three-dimensional (3D) printing and sol infiltration technology, is developed to further improve impedance matching with the equivalent electromagnetic effect. Simulation and experimental results demonstrate that the SiO2–SiC/MWCNT TPMS meta-structure exhibits broadband EMW absorption performance, with the EAB reaching 7.2 GHz. This improvement is attributed to the synergistic regulation of the heterointerface structure and TPMS meta-structure, which provides a good balance between the requirements of electromagnetic loss and impedance matching. Additionally, the composites exhibit excellent oxidation resistance, as their EAB remains almost unchanged after exposure to 1000 °C for 6 h. This research offers a new design paradigm for ultrabroadband design of the nonmagnetic high-temperature absorbing materials.

Graphene-Enhanced CuW Composites for High-Voltage Circuit Breaker Electrical Contacts

To address the issue of over-standard short-circuit currents in a power system, it is imperative to enhance the comprehensive performance of the electrical contacts, which serve as the lynchpin of circuit breakers, so as to improve the breaking capacity of high-voltage circuit breakers. Graphene, as the most prominent two-dimensional carbon material in recent years, has garnered widespread applications across various fields. In this study, graphene-enhanced CuW composites for high-voltage circuit breaker electrical contacts were prepared innovatively using integrated vacuum infiltration technology. The innovative graphene-enhanced CuW composites significantly improved the mechanical, electrical, and ablation resistance properties, and have been successfully applied in the 252 kV/63 kA high-voltage SF6 circuit breakers, achieving 20 times effective consecutive full-capacity short-circuit current breaking. It provides a new route for the development and application of high-performance CuW electrical contacts. Looking ahead, it is planned to extend their application to higher voltage grade high-voltage circuit breakers.

Study on the effect of vacuum fusion infiltration technology on the properties of tungsten/copper joining interface

In this paper, based on the need for high-strength connections between all-tungsten-oriented plasma materials and thermal sinking materials of copper and its alloys in nuclear fusion devices, a study on the effect of tungsten surface laser micro structuring on the interfacial bonding properties of W/Cu joints was carried out. In the experiment, the connectors were prepared by vacuum fusion infiltration technology, and the effects of microgroove structure on the mechanical and thermal conductivity of W/Cu connectors were investigated under different parameters (including microgroove pitch, microgroove depth, and microgroove taper). The maximum shear strength is 126.0 MPa when the pitch is 0.15 mm and the depth is 34 μm. In addition, the negative taper structure, i.e., the width of the entrance of the microstructure is smaller than the width of the interior of the microstructure, is also investigated. The shear tests show that there is an approximately linear relationship between the shear strength of W/Cu and taper. Compared with the positive taper, the shear strength of the samples with the same morphological density and depth of the tungsten surface is significantly higher.

Preparation and long-term ablation behavior of Cf-reinforced ZrC-SiC coated C/C-ZrC-SiC composite

To improve the long-term ablation resistance of the C/C composite, the Cf-reinforced ZrC-SiC coated C/C-ZrC-SiC composite is fabricated by thermal gradient chemical vapor infiltration (TGCVI) technology and the subsequent polymer infiltration and pyrolysis (PIP) process. The coating shares the same carbon fiber felt with the matrix, which can strengthen the bond between the coating and the matrix. Results show that the composite has excellent long-term anti-ablation performance (the linear ablation rate of the composite is −0.64 µm/s after ablated for 120 s (3 × 40 s), and the coating can withstand ablation for 160 s (4 × 40 s) without destruction). With the reinforcement of carbon fibers, the coating is peeled layer by layer rather than destructed in the whole coating, and the coating still works in the subsequent ablation cycles (the linear ablation rate of the composite is 2.40 µm/s after ablated for 280 s (7 × 40 s)).

Ablation behavior of C/C-ZrC-SiC composite with gradient distribution of ZrC-SiC ceramics along the thickness

A novel C/C-ZrC-SiC gradient composite (GGC/C-ZS) is prepared via thermal gradient chemical vapor infiltration (TGCVI) technology combined with polymer infiltration and pyrolysis (PIP). And ablation tests are carried out to evaluate the thermal shock and ablation resistance. Results show that the GGC/C-ZS exhibits excellent anti-ablation performance (linear ablation rate is −2.12 μm/s) after ablation for 2 × 40 s (under 2500 °C). The high ZrC-SiC content in the surface region of GGC/C-ZS ensures a dense ZrO2 scale of the ablation center and helps withstand the high thermal stress induced by the ablation. During the ablation, the compact ZrO2 scale can block heat transfer from the surface to the matrix of GGC/C-ZS because of its low thermal conductivity, which can relieve the thermal etching and the massive loss of SiO2 beneath the ZrO2 scale. Besides, the gradient structure can also reduce heat mismatch between the ZrC-SiC ceramics and the C/C matrix, which can avoid the peeling off of the ZrO2 scale after a second ablation process.

Numerical Modeling for LSCF Electrodes with Nanocatalyst Infiltration

As a mixed ionic-electronic conducting (MIEC) material, lanthanum strontium cobalt ferrite (LSCF) is widely used for solid oxide cells (SOCs) in both fuel cell mode and electrolysis mode. The performance and stability of LSCF electrodes can be further enhanced by nanocatalyst infiltration. In this study, a numerical model is developed to investigate the performance of LSCF electrodes modified with infiltrated nanocatalysts. The multiphysics model describes the chemical/electrochemical reactions, charge conservation, and species transport within a SOC button cell. The electrochemical reactions are represented by Butler-Volmer type expressions which couples the physical processes of the cell. The microstructural properties are estimated from experimental imaging to improve the accuracy of the study. The changes of microstructural properties and reaction mechanisms due to nanocatalyst infiltration are also implemented to investigate the effects of infiltrated lanthanum strontium cobaltate (LSC) nanoparticles. The numerical model is first calibrated by adjusting model parameters for good agreement between simulated performance and experimental datasets for a referenced cell. Then the calibrated model is utilized to predict the polarization curves and impedance behavior for backbones with different grain sizes and composition volume fractions. The simulated results for both baseline backbones and infiltrated backbones are also thoroughly analyzed to extract the changes of different physical processes due to the nanocatalyst infiltration. The comparison of performance changes among the backbones under this study provides guidance about the optimum backbone for nanoparticle infiltration technology.

Infiltration of silica slurry into silica-based ceramic cores prepared by selective laser sintering based on pre-sintering

The silica-based ceramic core is an important mold for manufacturing hollow blades. The preparation of silica-based ceramic cores by combining selective laser sintering (SLS) and vacuum infiltration (VI) technologies is a promising approach. To enhance infiltration effect, pre-sintering was introduced to obtain the bodies with high porosity and hydrophilicity. The infiltrated silica content increased from 29.58 wt% for samples infiltrated once to 68.91 wt% for samples infiltrated three times. The increase of silica content in the matrix reduced the porosity of final ceramics, thus improving the room-temperature flexural strength. The infiltrated silica gradually transformed into cristobalite during the high-temperature test, which improved the high-temperature flexural strength and creep resistance. When the final-sintering temperature was 1225 °C, room-temperature and high-temperature flexural strength reached 21.17 MPa and 21.21 MPa, respectively, due to the enhanced sintering necks and low porosity. These results indicate that our work provides a promising route to fabricate silica-based ceramic cores by SLS technology.

Shape retention of W-30Cu composites prepared by 20 wt% Cu melt infiltration into W-10Cu green parts made via BJ3DP

In this work, W-30Cu, W-10Cu, and W green parts were fabricated using BJ3DP, and then 0 wt% Cu, 20 wt% Cu, and 30 wt% Cu were infiltrated to prepare W-30Cu composites, respectively. The effects of Cu infiltration content (0–30 wt%) on the shape retention and properties of W-30Cu composites were studied. The experimental results showed that when the Cu infiltration content was 20 wt%, the W-30Cu composite prepared by 20 wt% Cu melt infiltration into W-10Cu green part had the best shape retention, its shrinkage was within 0.5%, and the relative density and thermal conductivity were 97.75% and 218 W·m−1·K−1, respectively. In this work, a high-shape-retention W-30Cu composite was obtained by treating W-10Cu green part prepared by BJ3DP using a combination of sintering technology and infiltration technology, while also providing a high-shape-retention method for other composites.

Porous ceramics derived from steel slag/coal gangue mixtures using cigarette butts as the pore‐forming agent

AbstractFabrication of ceramic materials with interconnected pores is necessary to improve thermal energy storage efficiency in high‐temperature infiltration technology. In the present study, industrial wastes such as coal gangue, steel slag, etc., were selected as the raw materials to prepare ceramics with interconnected pores. By adopting 50% cigarette butts as the pore‐forming agent, steel slag–coal gangue mixtures with a mass ratio of steel slag to coal gangue of 1:9 were sintered at 1100°C, and ceramics with interconnected elongated pores were prepared successfully. The highest apparent porosity and lowest volume density of the as‐prepared ceramics were ca. 73% and .74 g/cm3, respectively. Further measurements of the thermophysical properties indicated that no obvious mass loss was observed in the temperature range from ambient temperature to 800°C. The maximum values of specific heat and thermal conductivity were 1.38 J/(g K) and 1.661 W/(m K), respectively, and meanwhile the minimum compressive strength could exceed 3.5 MPa. These research results implied that the as‐prepared steel slag–coal gangue ceramics can provide long‐term service and offer excellent thermal stability over a wide temperature range. Therefore, they should have potential applications in high‐temperature infiltration technology.

Unusual ablation behaviors of tungsten graded network reinforced copper composites synthesized by 3D printing and infiltration sintering at ultra-high temperatures

Tungsten network reinforced functionally graded copper composites were prepared using an integrated 3D printing and infiltration technology to improve high temperature ablation properties of nuclear fusion divertor materials. The composites' ablation behavior was systematically investigated using an argon arc welding torch. Results showed that mass loss of composites was increased firstly but then decreased with the increase of ablation time. During ablation, evaporation of the melted copper reduces the local temperature of tungsten skeleton, whose high melting point also restrict the further evaporation of copper. These mechanisms significantly improve the ablative resistance of CuW gradient composite. Tungsten twinning structures were identified to form during ultra-high temperature (at 6273.15 K) ablation process in a cold environment in air. The formation of distinctive W twinning structures and gradient distribution of copper and tungsten skeleton were identified as the key mechanisms for the significantly enhanced ablation performance of the graded composite.

A novel metal-ceramic composite combining the structures of nacre and nanofiber reinforced foam

Lightweight high-strength and tough composites have enormous potentials in a multitude of fields including biomaterials, sporting goods, aerospace and automobile industries. Herein, we present a strategy to develop a novel bulk Al/SiC composite with a nacre/foam hybrid structure to combine excellent lightweight of foams with outstanding strength and toughness of nacre. To reduce the adverse effect of foam pores on mechanical properties, we further propose to strengthen the foams with 3D nanofiber networks, obtaining a nacre/nanofiber reinforced foam structure. Simultaneously, new particle-bubble co-assembly and selective infiltration technologies are proposed to prepare the novel nacre/foam and nacre/nanofiber reinforced foam structures. The nacre/nanofiber reinforced foam composite shows greater specific strength and toughness than the nacre/foam composite, conventional dense Al/SiC composites and many engineering materials. Our approach opens a promising new avenue for the structure design and manufacturing of lightweight, high-performance structural materials.

Microstructural characterization of the CGB graphite grade from the molten salt reactor experiment

In the 1960s, the Molten Salt Reactor Experiment demonstrated the feasibility of molten salt reactors for civil applications. The Molten Salt Reactor Experiment used a nuclear graphite grade known as CGB in the core as the fast neutron moderator. For application in this purpose, CGB graphite underwent additional impregnation steps that are not typically used in conventional nuclear graphites. These additional impregnations significantly lowered the permeability and reduced the size of pore openings in CGB graphite, for the purpose of inhibiting molten salt ingression into the graphite. Although several publications report the mechanical properties and irradiation response of CGB graphite, little information has been published about the microstructure or sealant used for this graphite grade. Here the results of multiple advanced microscopy techniques are presented with the objective to investigate the unique microstructure and sealing technology of legacy material from the Molten Salt Reactor Experiment so it can be potentially readopted for modern reactors. The microstructural characterization shows that some pores were fully sealed by the impregnation whereas other regions contained foam-like materials that partially filled the void content. This manuscript also investigates and documents the nature and possible source of the sealant material. The pore sealing methods used for CGB are discussed and compared with other common technologies used to reduce the impregnation of molten salts into graphite components. Knowledge of CGB graphite's microstructure can enable development of new pore infiltration technologies to improve in operando behavior advancing the next generation of molten salt reactors.

3D-printed bioinspired Al2O3/polyurea dual-phase architecture with high robustness, energy absorption, and cyclic life

Ceramics are attractive for structural components because of their excellent load-bearing capacity. Nevertheless, inferior energy-absorbing ability and poor reliability under common quasi-static and dynamic environments, especially under cyclic loading, extremely limit the popularization of ceramic components. The coupling between cellular structures inspired by the light but strong porous trabeculae and core–shell structure in strong and tough natural materials provides a solution for strengthening the load-bearing capacity, energy absorption ability, and cyclic life of ceramic components. Here, we proposed a bioinspired cellular ceramic structure/polyurea (CCS/polyurea) dual-phase architecture via additive manufacturing and simple infiltration technologies. It was demonstrated that the specific load-bearing capacity and energy-absorbing ability of bioinspired CCS/polyurea dual-phase architecture under quasi-static compressive loading were 2.22 and 50.34 times of CCS, respectively. Significantly, it could be repeatedly loaded at 40.28 and 48.82 MPa for over 120 and 8 cycles, respectively. Furthermore, CCS/polyurea dual-phase architecture performed extraordinary cyclic life under dynamic loading. The cyclic lives of CCS/polyurea dual-phase architecture at impact speeds of ∼ 6 and ∼ 12 m/s reached as high as 11 and 2, respectively. This research provides a credible approach to building ceramic-based materials with extraordinary load-bearing capacity, energy absorption ability, and especially remarkable cyclic life.

Preparation and electromagnetic wave absorption properties of PDC–SiC/Si3N4 composites using selective laser sintering and infiltration technology

Polymer-derived silicon carbide/silicon nitride (PDC–SiC/Si3N4) composites were prepared by additive manufacturing and infiltration technology. The composite green bodies were prepared using selective laser sintering (SLS) three-dimensional (3D) printing technology. Carbon-rich PDC–SiC was generated via precursor infiltration and pyrolysis (PIP) to increase the dielectric constant and enhance the electromagnetic wave (EMW) attenuation ability of the composites. Low-dielectric materials, including Al2O3, TiO2, and AlPO4, were introduced by sol infiltration to improve the impedance-matching characteristics of the composites. The results showed that the EMW absorption ability of the PDC–SiC/Si3N4 composites enhanced after two and four PIP cycles, whereas it degraded with further increasing the PIP cycle number. Among all the samples, the PDC–SiC/Si3N4 composite after four PIP cycles displayed an excellent EMW absorption ability with the minimal reflection loss of −46.79 dB, whereas its effective absorption bandwidth was narrow. Comparing to the sample without infiltration, the effective absorption bandwidth of the samples after the infiltration treatment with TiO2 or Al(H2PO4)3 sol increased from 1.44 GHz to 4.08 GHz and 3.52 GHz, respectively. These results demonstrate that the PIP process and infiltration with TiO2 or Al(H2PO4)3 sol resulted in a 3D-printed PDC–SiC/Si3N4 ceramic that is a promising EMW absorption material suitable for high-temperature environments.

Achieving ultra-high strength in Be/Al composites by self-exhaust pressure infiltration and hot extrusion process

Beryllium particle reinforced aluminum matrix (Be/Al) composite with exceptionally high strength was fabricated from Be debris by self-exhaust pressure infiltration and hot extrusion process. The microstructures characteristics and mechanical properties of the Be/Al composite at as-cast and as-extruded state were systematically investigated in the current study. It was found for the as-cast composite that uniform distribution of beryllium particles with average size of 2.2 μm were achieved, the microcracks in beryllium particles were repaired in situ by infiltrating liquid aluminum into these microcracks under external pressure. The Be phase and Al phase were well bonded despite the presence of nano BeO at the interface. After hot extrusion, the beryllium particle deformed and elongated along the extrusion direction. The average grain size of Al was refined from hundreds of microns to 450 nm, and the dislocation density increased significantly. The tensile strength and yield strength of Be/Al composite reached 595 MPa and 494 MPa by hot extrusion, respectively. The ultra-high strength was mainly related to grain boundaries strengthening, dislocation strengthening, precipitation strengthening and load transfer strengthening. Compared with the composites prepared by the investment casting and powder metallurgy methods, the Be/Al composite showed more than 100% increment in strengthening efficiency and 80% increment in yield strength. It indicated that the self-exhaust pressure infiltration technology combined with hot extrusion process was a feasible and successful method to prepare high performance Be/Al composites.