Melt Infiltration Research Articles

Boninitic melt percolation makes depleted mantle wedges rich in silica: COMMENT

Boninitic melt percolation makes depleted mantle wedges rich in silica: COMMENT

Geochemical diversity of continental arc basaltic mushy reservoirs driven by reactive melt infiltration

The reactive melt flow emerges as an important factor for diversification of basaltic magmatic reservoirs, but whether and how it influences continental arc basaltic mushes are enigmatic. Here, we used mineral and whole-rock geochemistry to examine the petrogenesis of a suit of mafic and intermediate plutons in western Yangtze Block, which were emplaced at continental arc crust and primarily had plagioclase and clinopyroxene as early cumulate mineral phases. We found the crystal mushes were infiltrated by externally-derived reactive melt with high δ18O and fertile crustal signatures, resulting in the changes of mineral phases (e.g., clinopyroxene transformed to hornblende) and bulk-rock geochemistry (including isotopes). Then, the reacted granitic melt was prone to either be extracted from or stall in the crystal mushes, generating quartz-poor (mafic) or quartz-rich (intermediate) plutons, respectively. This study supports the reactive melt infiltration may serve as an important engine for compositional diversity of basaltic mush system within continental arc settings.

High strength and high toughness Csf/SiC composites prepared by laser powder bed fusion/ reactive melt infiltration with the impregnation of boron-and silicone-containing phenolic resin

Laser powder bed fusion (LPBF) has emerged as an effective method for preparing complex structured silicon carbide (SiC) ceramics. However, the SiC components demonstrate low strength and high brittleness, which remain major challenges limiting its application. To overcome this limitation, short carbon fiber reinforced silicon carbide (Csf/SiC) composites are prepared by combining LPBF and phenolic resin binder impregnation (PRBI)-reactive melt infiltration (RMI), in which high char yield boron-and silicone-containing phenolic resin (BSiPF) impregnation is used to adjust the carbon density of green bodies and to reduce the pore size of green bodies. By optimizing the impregnation process, the carbon density can be brought close to the theoretical optimal value of 0.84 g/cm3, and the reduction of the pore size is conducive to the improvement of the reaction rate at the early stage of the reaction, which enhance the SiC phase content of Csf/SiC composites obtained by RMI. Meanwhile, the application of BSiPF results in a protective pyrolytic carbon (PyC) coating on the surface of Csf, which can reduce the erosion of Csf by molten Si during the RMI process, thus improving the fracture toughness of Csf/SiC composites. The final Csf/SiC composites exhibit the enhanced bulk density, bending strength and fracture toughness, reaching 2.90 ± 0.01 g/cm3, 257 ± 20 MPa, 3.52 ± 0.15 MPa m1/2, respectively. This study provides a new strategy for effective impregnation technique for the additive manufacturing (AM) of high strength and high toughness SiC composites.

Effects of preform structure on microstructure and mechanical properties of long/short fiber‐coupled C/C–SiC composites

AbstractC/C–SiC composites with four different preform structures were prepared via chemical vapor infiltration and reactive melt infiltration (RMI). The effects of preform structure on the microstructure and mechanical properties of the C/C–SiC composites were thoroughly investigated. The results indicate that the porous C/C composites with multidirectional long/short fiber‐coupling exhibited consistent pore size distribution (diameter: 5–300 µm) and periodicity pore distribution characteristics. As the effective fiber volume fraction in the loading direction of the C/C–SiC composites increased from 11.71% to 21.04%, the tensile and flexural strength significantly increased by 64.44% and 44.03%, respectively, with minimal effect on compressive and interlaminar shear properties. The introduction of Z‐direction fiber, such as stitched structure, increased the compressive and interlaminar shear strength of the composites by 10.87% and 15.67%, respectively. A theoretical predictive model of ultimate tensile strength after modification was validated for application to the C/C–SiC composites prepared by RMI, through characterization of the volume fraction of each layered unit and the content of each component. However, the presence of defects caused by the stitched structure, such as fiber bending, occupancy, and pores, reduced tensile and flexural strength by 30.45% and 28.56%, thereby impacting the effectiveness of the predictive model negatively.

Microstructure and ablation behaviour of C/C-SiC-ZrC-Cu composites prepared by reactive melt infiltration

To satisfy the requirements for the new generation solid rocket motors on high ablation-resistant throat materials, an idea that merges passive and active thermal protection together was applied to modify carbon/carbon composites. In this study, SiC and ZrC were used as passive thermal protection materials along with the active thermal protection material Cu to modify C/C composites. C/C-SiC-ZrC-Cu composites were prepared by two-step reactive melt infiltration, which involved the infiltration of Si/Zr followed by Cu/Ti. The Cu content of the C/C-SiC-ZrC composites was controlled by controlling the open porosity of the porous C/C-SiC-ZrC composites. Microstructure, composition and ablation resistance of the C/C-SiC-ZrC-Cu composites were investigated. The results showed that the composites with high Cu content and density exhibited excellent short-term ablation resistance under the 42 kW plasma flame, with a negative linear ablation rate after 20 s of ablation. The active heat dissipation of Cu during the ablation process results in a significant reduction of the thermal response temperature on the composite surface. Moreover, the generated Si-Ti-Zr-O layer could form an effective barrier to protect the matrix.

Fabrication of MAX‐Phase Composites by Novel Combustion Synthesis and Spontaneous Metal Melt Infiltration: Structure and Tribological Behaviors

In this work, a new scheme is developed and experimentally tested for fabricating family of MAX–metal composites. This scheme combines the combustion synthesis (CS) process to obtain a porous MAX‐phase skeleton and process of metal melt infiltration spontaneously, which is then used to fabricate Ti3SiC2–TiC–Sn and Ti3SiC2–TiC–(Sn–Pb) composites. The resultant composite samples have an uneven density along the length, which steadily decrease from the point of contact of the sample with the molten tin to the opposite edge. Existence of Ti3SiC2, TiC, Sn, and (Sn and Pb) phases in the composite samples is confirmed using X‐ray diffraction and energy‐dispersive spectroscopy analyses. Comparative tribological characterizations are performed on fabricated Ti3SiC2–TiC–Sn and Ti3SiC2–TiC–(Sn–Pb) composite samples. Herein, these results are compared against standalone Sn and Sn–Pb samples as baseline and reveal major differences in friction and wear mechanisms due to addition of select MAX phases via novel CS process. As a whole, in the present study, a novel synthesis process is established to fabricate MAX‐phase composites and its enhanced tribological behavior and wear mechanisms which can have plethora of applications ranging from aerospace, automotive to biomedical sectors, are validated.

Pliocene to Pleistocene REE-P Metasomatism in the Subcontinental Lithosphere beneath Southeast Asia—Evidence from a Monazite- and REE-rich Apatite-bearing Peridotite Xenolith from Central Vietnam

Abstract Mantle rocks usually contain rare earth elements (REEs) in very low concentrations. Here, we document an occurrence of monazite associated with REE-rich apatites in a carbonate-bearing wehrlite xenolith from central Vietnam. The xenolith displays an equigranular matrix of rounded olivine grains while texturally primary orthopyroxene, clinopyroxene and spinel are notably absent. Scattered within the olivine matrix, two types of domains are present: domain-I contains blocky clinopyroxene grains within a matrix of quenched silicate melt and is associated with a second generation of olivine, small euhedral spinel, and rare grains of carbonates. Domain-II contains irregularly shaped patches of carbonate associated with silicate glass, secondary olivine, spinel, and clinopyroxene. Monazite and apatite occur only in domain-I: very small rounded to elongate monazite I grains are included in primary olivine, partly crosscut by fine glass veinlets, monazite II as large grains up to 300 × 200 μm in size and monazite III as small euhedral and needle-like crystals in silicate glass pools. Apatite I forms lath-shaped to rounded crystals up to 200 × 50 μm in size, whereas apatite II is present within silicate melt pools where it forms euhedral needle-like to equant grains. Monazites show compositional variation mainly with respect to ∑REE2O3 (63–69 wt %) and ThO2 (1.1–5.3 wt %) and only minor variations in P2O5 (29–32 wt %), SiO2 (<0.05–0.4 wt %), and CaO (0.2–0.4 wt %). Apatites are characterized by strongly variable and high REE2O3 and SiO2 contents (4–27 wt % ∑REE2O3, 0.6–6.8 wt % SiO2) as well as with significant Na2O (0.3–1.5 wt %), FeO (0.1–1.8 wt %), MgO (0.2–0.6 wt %) and SrO (0.2–0.9 wt %) contents. F and Cl contents are in the range 1.9–3.0 wt % and 0.2–0.8 wt %, respectively. The textures observed in this wehrlite xenolith are thought to be the result of an interaction of depleted (harzburgitic) mantle with cogenetic silicate and carbonatite melts formed by fractionation-driven immiscibility within a parental SiO2 undersaturated melt characterized by high P, CO2, and REE contents. The immiscibility occurred in the shallow subcontinental lithosphere at T of 700–800 °C and a depth of ~30 km and the melt–rock interaction occurred in two successive and most likely nearly simultaneous events: an initial stage of metasomatism was triggered by the P-REE-CO2-rich agent with low aH2O resulting in the co-precipitation of carbonates as patches and along micro-veins and of phosphates in a peridotitic assemblage. A second stage is characterized by pervasive infiltration of an alkali-rich basaltic melt into the carbonate + phosphate-bearing assemblage. Based on 232Th and 208Pb contents of monazite, a young age of ~2 Ma can be calculated for the timing of the monazite-forming metasomatic imprint. Based on 39Ar-40Ar extrusion ages of the xenolith-hosting alkali basalts of 2.6–5.4 Ma, this indicates that both carbonatite and basaltic melt infiltration must have occurred no more than a few hundred thousand years before extraction of the xenolith to the surface.

Effect of different rare earth fluoride doping on microstructure and ablation properties of C/C–ZrC–SiC composites prepared by molten salt assisted reactive melt infiltration

The effect of doping with rare earth elements of different ionic radii on the ablation resistance of C/C–ZrC–SiC composites was investigated and the ablative behavior and ablation resistance of C/C–ZrC–SiC composites with the addition of different rare earth elements was tested. Although rare-earth doped stabilized zirconia has been used for a long time in the field of thermal barrier coatings, the existing techniques are usually coating modifications with rare-earth oxide or boride additions, it is difficult to prepare coatings that can be used on the surface of carbon matrix materials due to the large difference in the coefficients of thermal expansion. Therefore, this study attempts to introduce rare earth components into the interior of C/C–ZrC–SiC composites for matrix modification. The results show that the addition of rare earth elements enhances the ablation performance of the composites, but the mechanism of enhancement is different: rare earth ions with a smaller radius difference from Zr4+ ions stabilize the crystal structure of ZrO2 by forming replacement solid solutions and stabilize the surface oxide film structure by preventing the homogeneous multiphase transformation of the oxide to achieve higher ablation performance; whereas rare earth ions with a larger radius difference from Zr4+ ions cannot stabilize ZrO2 by replacement solid solutions, but instead form high viscosity, low volatility liquid phase oxides to heal the surface defects of the oxide film and reduce liquid phase dissipation to enhance ablation performance.

Novel high thermal conductivity alumina/salt composites for thermal energy storage: Effect of wettability on microstructure and properties

In this work, alumina foam ceramics (AFC) were prepared by foaming method, and AFC/salt composite phase change materials were prepared by melt infiltration method using AFC as skeleton materials. The results showed that AFC had good chemical compatibility with Na2SO4 and NaCl. The salt contents of AFC/Na2SO4 and AFC/NaCl were 37.8 wt% and 31.7 wt%, respectively, with compressive strength of 100.1 MPa and 72.8 MPa, thermal conductivity of 5.53 W/m·K and 6.40 W/m·K, and energy density of 1129 J/g and 1019 J/g, respectively. Due to the better wettability, AFC and Na2SO4 form a chimeric structure, which has better binding and bonding strength, and is not prone to molten salt leakage. AFC/ Na2SO4 is expected to be applied to industrial waste heat recovery and solar thermal power generation with periodic temperature changes.

Stabilization and evolution of the Brazilian subcontinental lithospheric mantle: Insights from garnet xenocrysts and peridotite xenoliths of Três Ranchos kimberlite (APIP, Brazil)

The thermal structure and chemical composition of the subcontinental lithospheric mantle beneath the Alto Paranaíba Igneous Province defined by the major and trace element compositions of garnet and clinopyroxene xenocrysts and mantle peridotite xenoliths entrained in the Cretaceous Três Ranchos kimberlite. Estimated temperatures and pressures indicate a typical cratonic geotherm, with a surface heat flow of ∼ 40 mW/m2 slightly hotter than that at the São Francisco Craton margin (35–36 mW/m2), suggesting lateral heterogeneities in the geothermal gradients. A deep mantle portion (160 km) is recorded by a lherzolite xenolith (5 GPa and 1200 °C). This portion has undergone pervasive interstitial melt percolation of an ultra-alkaline silicate melt and late injection of small silicate melt fractions such as the host carbonated kimberlite. This pervasive migration extended into shallower SCLM sectors at 124–100 km (3.9–3.1 GPa and ∼ 940–810 °C) as evidenced by metasomatized (±phlogopite) peridotite identified by sinusoidal REE garnet compositions. This portion is apparently intercalated at 120–110 km depth (3.7–3.3 GPa and ∼ 850 °C) with strongly depleted peridotites showing garnet and clinopyroxene compositions extremely impoverished in moderately incompatible elements, as a result of extreme ancient, melt extraction. Atop the metasomatized and depleted peridotites, at 100 km depth, a layer of fertile lherzolite is identified by garnet xenocrysts, with 'normal', HREE-enriched, steadily fractionated LREE-depleted patterns. Combining our data with those of the Osvaldo França SCLM points to the occurrence of a deeper sector (>100 km depth beneath Trȇs Ranchos) originally formed by extremely depleted peridotites, successively metasomatized by ultra-alkaline melts; and a shallower sector of the São Francisco craton composed of fertile lherzolites unrelated to ultra-alkaline magmatism. Similar fertile lherzolites are found in the uppermost sectors of the Siberian and Kaapval SCLM, suggesting that they may be a ubiquitous, primary feature, possibly related to the stabilization of the Archean cratons.

Material design using calculation phase diagram for refractory high‐entropy ceramic matrix composites

AbstractTo achieve Si‐free refractory ceramic matrix composites exposed to an oxidizing atmosphere at approximately 2000°C, a Ti–Zr–Mo ternary alloy melt‐infiltration (MI) method was developed for the production of carbon fiber‐reinforced refractory high‐entropy ceramic matrix composites (C/RHECs), with high‐entropy carbides serving as the matrix. This approach was designed using calculation phase diagrams (CALPHADs) and the calculation of thermodynamic parameters. The combination of CALPHAD and the calculation of alloy and carbon reactivity enabled the prediction of reaction and infiltration behavior into a preform comprising carbon fiber, carbon black, and transition metal carbide powders. Furthermore, C/RHECs featuring a (Ti, Zr, Hf, Nb, Ta, Nb, Mo)C matrix were experimentally fabricated through the Ti–Zr–Mo alloy MI method in accordance with the design. The arc‐wind tunnel tests on the C/RHECs conducted at approximately 2000°C revealed surfaces covered with complex oxides. The apparent oxidation rate of the C/RHECs was similar to that of Si‐containing ceramics and composites. These results indicate that complex oxides act as a barrier to oxygen diffusion toward unoxidized regions, making Si no longer essential for protecting materials from oxidation above 2000°C.

Melt infiltration for the preparation of finely dispersed Ni-FeOx nanoparticles on SBA-15 for the hydrodeoxygenation of m-cresol

The polymer-assisted melting infiltration method was used to finely disperse Ni, Fe and bimetallic Ni-Fe precursors in ordered mesoporous SBA-15 support. This approach allowed to obtain small Ni nanoparticles, in the order of 2 nm in size, with finely dispersed iron oxide surrounding metallic Ni, without evidence of Ni-Fe alloy formation. The catalysts were used in the HDO reaction of m-cresol at 300 °C and atmospheric pressure. The conversion of m-cresol was found to be dependent on Ni content, with the total reaction rate decreasing when Ni is partially replaced by iron. Toluene was the main product obtained for both, mono Ni and bimetallic Ni-Fe catalysts, thus suggesting that nickel nanoparticles when in the form of small sized particles, are the active sites for deoxygenation, independent on the presence of oxophilic iron site in their proximity. Such findings will serve for the further design of effective catalysts for the upgrading of lignin-derived bio-oil.

Additive manufacturing of high-performance CCF/SiC composites under dual protection

In this work, chopped carbon fibre reinforced silicon carbide (CCF/SiC) composites were fabricated by selective laser sintering (SLS) combined with reaction melt infiltration (RMI), using the SiC interface and pyrolytic carbon layer as a dual protection to protect the CCF from the erosion of molten silicon. The pyrolytic carbon layer encapsulates the CCF@SiC and the outer carbon preferentially reacts with silicon to form a β-SiC layer, which hinders the reaction of liquid silicon to CCF. Moreover, the fine-crystal β-SiC generated by the Si–C reaction optimizes the microstructure and enhances the mechanical performance of CCF/SiC composites. The CCF under the dual protection maintains its original high strength and high modulus, and the toughness of the CCF/SiC composites is significantly improved through the fibre debonding and fibre pull-out mechanism. The bending strength and toughness of CCF/SiC composites are 265.2 MPa and 3.5 MPa m1/2, respectively. The insights gained from this study contribute to a better understanding of microstructural engineering in SLS&RMI-fabricated CCF/SiC composites. This paves the way for future breakthroughs in composite material design and low-cost manufacturing for extreme environments.

3D observations of room temperature capillary infiltration mechanism in SiC compacts

The melt infiltration of a liquid metal is a successful method for densifying metal and ceramic matrix composites (CMC). The reduction of residual porosity of silicon carbide composites by infiltration of molten silicon into the matrix allows to reach interesting mechanical properties. However, fluid progression within the pore network of the granular matrix is a complex phenomenon, driven by physical and thermomechanical mechanisms that are not yet fully understood. This publication focuses on the capillary impregnation at room temperature and highlights important parameters related to the physical aspect of the process. Two different model fluids (n-hexadecane and exo-dicyclopentadiene) were used to reproduce the behaviour of molten silicon alloy. During the infiltration, the monitoring of the infiltrated liquid weight, along with the image acquisition, was used to compare the infiltration difference between several types of samples. An innovative way to interrupt and fix liquid inside samples, based on rapid polymerization, was investigated during capillary rise experiments. The correlation between 2D observations and 3D volumes obtained by tomography outlines the existence of two different flow fronts, the surface flow front (SFF) which often have a flat shape, and a second inside the sample, the volume flow front (VFF), which shows a paraboloid shape.

Microstructure and Oxidation Behavior of ZrB2-SiC Ceramics Fabricated by Tape Casting and Reactive Melt Infiltration

Microstructure and Oxidation Behavior of ZrB₂-SiC Ceramics Fabricated by Tape Casting and Reactive Melt Infiltration

Research Progress of Ceramic Matrix Composites Prepared by Improved Reactive Melt Infiltration through Ceramization of Porous Carbon Matrix

Research Progress of Ceramic Matrix Composites Prepared by Improved Reactive Melt Infiltration through Ceramization of Porous Carbon Matrix

Microstructure evolution and properties of Hf/Zr-based UHTCs modified C/C composites prepared by reactive melt infiltration method

Different Hf/Zr-based UHTCs modified C/C composites were fabricated via the reactive melt infiltration (RMI) adopting HfSi2, ZrSi2, and HfSi2-ZrSi2 hybrid alloys with different molar ratios (3:1, 1:1, 1:3). The microstructural evolution of the composites, variation of mechanical properties, and ablation performance of the composites in the absence of in-situ coating were studied. The C/HfC-ZrC-SiC composites were all divided into the exterior region with more UHTC phases and the interior region with more SiC and silicides, and the UHTC-rich region enlarged with the HfSi2 content increased in the RMI alloy. The flexural strengths of C/HfC-ZrC-SiC were enhanced to 238.37 ± 20.42 Mpa and 237.26 ± 17.57 Mpa when adopting HfSi2-ZrSi2 alloys with molar ratios of 1:1 and 1:3. As the HfSi2 content in the RMI alloy increased, the oxide layer became compact with sintering degree increased, enhancing the ablation resistance of the composites and reducing the mass ablation rate.

Outstanding mechanical and ablation resistance of C/C–ZrC–W composites prepared via slurry impregnation and reactive melt infiltration at 1500 ℃

To improve the mechanical properties and ablation resistance of Cf-reinforced ceramic-based materials, ZrC–W cermet composites (C/C–ZrC–W) were prepared in C/C preforms using slurries and low-temperature reactive melt infiltration, and their microstructure, formation mechanism, and mechanical and ablation properties were investigated. The obtained results revealed that the formation of C/C–ZrC–W composites involved the dissolution–precipitation and C diffusion processes. Owing to the precipitation of W nanoparticles in the ZrC phase and interdiffusion of W/ZrC, the fabricated C/C–ZrC–W composites exhibited superior mechanical properties with a flexural strength of 280.65 ± 12.84 MPa and fracture toughness of 13.87 ± 0.56 Mpa.m1/2. The formation of a Zr–W–O dense oxide layer resulted in the excellent ablation performance of the C/C–ZrC–W composites in oxyacetylene flame with a temperature of 2200 °C, and their mass ablation rate and linear ablation rate were 1.14 mg/s and 2.42 µm/s, respectively. The described method can be potentially used for preparing high-strength, high-toughness, and ablation-resistant materials at low temperatures.

Performance enhancement in RMI-fabricated SiC-Ti3SiC2 composites via microstructure optimization

This study focused on improving SiC-Ti3SiC2 composites fabricated through reactive melt infiltration (RMI) using TiSi2 alloy to optimize their microstructure, mechanical, and corrosion properties. The results indicated that achieving a balance between the carbon black content and the porosity of the preforms led to a decrease in residual TiSi2 and an increase in the content of the MAX phase in the composites. The composite, derived from a SiC60-C40 preform with 35% porosity, contained 76 vol% SiC, 22 vol% Ti3SiC2, and 2 vol% TiSi2. The “time window” based on two reactions specific to the TiSi2 and C facilitates the creation of infiltration channels and the reduction of residual TiSi2. With minimal residual TiSi2, the composite exhibited a flexural strength of 395 MPa, a fracture toughness of 5.24 MPa·m1/2, and maintained over 70% of its original strength after thermal shock below 1200ºC. Enhanced corrosion resistance was attributed to a protective MgTiO3 layer.

Numerical simulation of melt penetration in debris beds using MPS method

During a severe accident of light water reactors (LWR), melt penetration in a debris bed (also called infiltration) may occur due to the failure of a crust which accommodates a molten pool over the debris bed, or due to earlier re-melting of metallic components (i.e., Zr and Fe) which has lower melting points than oxidic ones (i.e., UO2 and ZrO2) of corium debris. Although understanding and modeling of melt infiltration plays a significant role in the prediction of severe accident progression, little work has been done in this respect due to its complexity. To fill this knowledge gap, the present study develops a Moving Particle Semi-implicit (MPS) code with various models representing key physics in melt infiltration. REMCOD experiment, recently carried out at KTH, has been simulated to validate the updated MPS code. The comparative results show that the melt infiltration in the tests can be reproduced by the MPS code. For a debris bed of cylindrical particles, the melt infiltration process in the experiment can be predicted by using Sauter mean diameter of the particles in the simulation. The code is also applied to investigate the influences of important parameters on the melt infiltration, and it is found that contact angle has little impact on melt penetration process in the case of debris beds with large pore sizes.