Ceramic Composite Materials Research Articles

USING THE ADVANTAGES OF NANOTECHNOLOGY FOR THE PRODUCTION OF COMPOSITE MATERIALS OF THE TYPE NGO/CERAMIC MATRIX

Using the advantages of nanotechnology, composite ceramic materials of the type of graphene oxide nanocolloid/ceramic matrix were obtained in two stages. First, finely porous corundum (1500ºC) and barium titanate (1300ºC)ceramic samples containing 2 mass % graphene structures nanoplatelets were synthesized. The next stage of the study involved the preparation of graphene oxide in nanocolloid form (2 mg/ml, dispersion in H2O) which was impregnated in the solid porous ceramic samples to obtain composite materials. For the characterization of the ceramic samples, mainly infrared spectroscopy, X-ray phase analysis, scanning electron microscopy and light microscopy were used. The results obtained from the studies carried out showed that with the introduction of small amount of graphene nanoplatelets in the initial blends followed by solid state sintering, part of the added graphene is burned out which imparts significant porosity to the ceramics obtained. On the other hand, the addition of graphene initiates the formation of well-shaped fine-grain structure of the ceramic samples, and they had sufficient porosity.

Glass-ceramic binder of cordierite composition for low-temperature sintering of high-strength ceramic materials based on oxygen-free silicon compounds

The mechanical properties of composite ceramic materials obtained based on oxygen-free silicon compounds are largely determined by the properties of the glass binder. This paper presents the results of studies aimed at determining the most fusible glass in the pseudo-binary system 2MgO2Al2O35SiO2–2MnO2Al2O35SiO2 with a high tendency to crystallize as a glass-ceramic binder for low-temperature sintering of high-strength ceramic materials based on oxygen-free silicon compounds. The crystallization tendency of the experimental melts decreases with an increase in in the content of manganese cordierite, as confirmed by X-ray and infrared spectroscopic studies. Based on experimental studies, a melting diagram was constructed, which was used to determine the ratio between magnesium cordierite and manganese cordierite (50:50 wt.%), ensuring a minimum melt temperature of 12750C. The melting point of the glass of the specified composition is 14500C. The synthesized glass is characterized by a softening point of 8000C and crystallizes intensively at 10300C. The The thermal coefficient of linear expansion of the crystallized glass samples is 20.810–7 0C–1. X-ray diffraction and electron microscopic studies have shown that the developed glass is almost completely crystallized during heat treatment for 2 hours, forming a cordierite solid solution 2(Mg,Mn)O2Al2O35SiO2. The size of the cordierite phase crystals ranges from 0.5 to 3.0 m. Due to its fusibility and high crystallization tendency, the developed glass, can be proposed as a promising glass-ceramic binder for the production of high-strength ceramic materials (wear and impact resistant) based on SiC and Si3N4 with reduced sintering temperatures.

Toughening Mechanism of CaAl12O19 in Red Mud–Al2O3 Composite Ceramics

The utilization of red mud in the production of ceramic products represents an efficient approach for harnessing red mud resources. Composite ceramics were prepared from Al2O3, red mud, and Cr2O3 by atmospheric pressure sintering, and the phase composition and microscopic morphology of the composite ceramics were investigated by XRD, SEM, and EDS. The flexural strength and fracture toughness of composite ceramics were measured by three-point bending and SENB methods. The results showed that the composite ceramics sintered at 1500 °C with the addition of 1.5 wt.% Cr2O3 had a flexural strength of 297.03 MPa, a hardness of 17.44 GPa, and a densification of 97.75% and fracture toughness of 6.57 MPa·m1/2. The addition of Cr2O3 helps to improve the low strength of red mud composite ceramic samples. The CaAl12O19 phase can form a similar “endo-crystalline” structure with Al2O3 grains, which changes the fracture mode of the ceramics and thus significantly improves the fracture toughness. The wettability tests conducted on Cu and RM–Al2O3 composite ceramic materials revealed that the composites exhibited non-wetting behavior towards Cu at elevated temperatures, while no interfacial reactions or elemental diffusion were observed. Composites have higher surface energy than Al2O3 ceramic at high temperatures. The present study provides a crucial foundation for enhancing the comprehensive utilization value of red mud and the application of red mud ceramics in the field of electronic packaging.

Flexural Strength of Modern CAD/CAM Restoratives After Artificial Aging.

Before clinical trials are initiated, studying the mechanical performance of modern CAD/CAM restorative materials exposed to aging conditions would provide insights on their performance in service. This study evaluated the impact of thermomechanical aging on various resin composite, ceramic, hybrid, and nano-filled resin composite materials after two polymerization modes. Specimens (3 × 4 × 14 mm3) were fabricated using (n = 12 per group) a universal composite (Filtek Supreme XTE photo-polymerized for either 40 s or 120 s per layer), hybrid ceramics (BRILLIANT Crios, GC Cerasmart, Lava Ultimate, VITA ENAMIC), glass ceramics (IPS e.max CAD, VITA Suprinity PC, Straumann n!ce), or feldspar ceramics (VITABLOCS Mark II, GC Initial LRF). In each group, half of the specimens underwent thermomechanical aging. A three-point bending test was applied to all specimens and the results were statistically analyzed (α = 0.05). Glass ceramics and hybrid ceramics presented higher flexural strength values than feldspar ceramics and the universal composite before and after aging (p < 0.05). Thermomechanical cycling affected the flexural strength of all materials (p < 0.05) except Lava Ultimate, Straumann n!ce, and GC Initial (p > 0.05). The highest decrease in flexural strength after aging was found in the universal composite (40 s polymerization) (p < 0.001) and Vita Enamic (p < 0.001), while the lowest decrease was in the hybrid ceramics, Cerasmart and Lava Ultimate (p < 0.05). Extending polymerization duration reduced the aging effect on the universal composite tested. Thermomechanical aging affected the flexural strength of most materials tested. Universal composites and feldspar ceramics presented similar flexural strength values.

Spark plasma sintering of Ti2AlC/TiC MAX-phase based composite ceramic materials and study of their electrochemical characteristics

A novel method for obtaining the MAX phase Ti2AlC from TiC, Al4C3, and Ti precursors has been demonstrated, involving activation of the mixture in a high-energy ball mill (HEBM) followed by Spark Plasma Sintering (SPS). The phase composition, mechanical characteristics, surface microstructure, and electrochemical behavior in neutral media (0.1 M Na2SO4) of heterogeneous composite ceramic materials TiC/Ti2AlC were studied as a function of sintering temperature (1200–1400 °C). SPS at 1200 °C yields materials with a relative density of 94.42 % and Ti2AlC mass content up to 57 %. These composite materials exhibit capacitive behavior according to cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) data, with a capacitance of 73 mF/g, suggesting their potential application as lead-free ceramic capacitors. Further increase in sintering temperature (1300–1400 °C) leads to increased electrical resistance and enhanced sample homogeneity.

Effect of alumina or zirconia particles on the performance of lead-free BCZT piezoceramics

The barium titanate derivative Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) offers high dielectric and piezoelectric performance but has poor mechanical properties. Ceramic composite materials combining BCZT with tougher Al2O3 or ZrO2 could be the solution to the inherent brittleness of electroceramics. This work focuses on BCZT with 1–5 vol.% addition of reinforcing phase dispersed in the microstructure. While hardness was improved in all composites, especially in ZrO2-reinforced BCZT, toughness was positively affected only by Al2O3. The chemical reactivity of BCZT during sintering resulted in the formation of new barium aluminate phases at the grain boundaries and possibly also within the grains, which affected the electrical properties of the composites. The addition of zirconia resulted in the formation of BaZrO3 or Ba(Zr,Ti)O3, which is a natural part of the BCZT solid solution and shifts the phase composition towards relaxor behaviour. ZrO2-reinforced composites exhibited higher permittivity but lower ferroelectric properties, accompanied by a substantial Curie temperature decrease.

Developing automated characterization techniques to quantify 3D datasets for ceramic matrix composite materials

Developing automated characterization techniques to quantify 3D datasets for ceramic matrix composite materials

Synthesis of ZrB2-SiC-ZrC composite powders with core-shell structure via sol-gel molecular modulation

In this study, ZrB2-SiC-ZrC (ZSZ) composite powders with molar ratios C/(B + Zr + Si) = 1.5, 1.9 and 2.4 were obtained by sol-gel method and boro/carbothermal reduction reaction. Meanwhile, the impact of heat treatment temperature (1100 °C–1600 °C) and holding time (1 h–2.5 h) on the resulting powders were studied. The results showed that the ZSZ powder precursors were first completely converted to ZrO2, SiO2, B2O3 and pyrolytic carbon after heat treatment at 1200 °C under the optimized molar ratio (2.4) and holding time (2.5 h). Then, the transformed oxidation products and pyrolytic carbon were completely transformed into ZSZ composite powders after optimized heat treatment at 1500 °C. The synthesized ZSZ composite powders are characterized by the core-shell structure, in which ZSZ particles act as the inner core are encapsulated by the low-crystalline ZrB2 phase as the outer shell to form a core shell structure. The ZSZ composite ceramic materials prepared using the core-shell structural powders have excellent ablative properties in the range of 2000 °C, with the mass and line ablation rate of −3.5 × 10−4 g/cm3 and 2.39 × 10−3 mm/s, respectively.

The magnesium-doped CSH/BCP promotes alveolar bone regeneration by mediating M2 macrophage polarization via miR-21–5p/Smad2 axis

The repair of alveolar bone defects is a complex biological process that involves the interplay between implant materials, bone marrow mesenchymal stem cells (BMSCs), and the immune cells present in the surrounding area. Moreover, the polarization of macrophages induced by implant materials has been shown to play a crucial role in regulating bone regeneration. Recent studies have discovered that M2 macrophages promote the osteogenic differentiation of BMSCs by activating the TGF-β/BMP signaling pathway. However, the molecular mechanisms underlying the regulation of bone regeneration in BMSCs by macrophages remain unclear. Our in vivo study demonstrated that a 10 % magnesium (Mg2+)-doped calcium sulfate hemihydrate -biphasic calcium phosphate (CSH/BCP) composite ceramic material was effective in repairing alveolar bone defects in rabbits. In our in vitro study, we observed that this ceramic material could induce M2 macrophage polarization and reduce inflammation. Moreover, the conditioned media obtained from M2 macrophages promoted the osteogenic differentiation of BMSCs. Additionally, our research showed that overexpression of miR-21–5p inhibited M2 macrophage polarization and reduced the osteogenic differentiation capacity of BMSCs. Co-overexpression of miR-21–5p and Smad2 in macrophages partially reversed the effects of miR-21–5p on the osteogenic differentiation of BMSCs and macrophage polarization. These findings suggested that Mg2+-doped CSH/BCP composite ceramic materials could enhance M2 macrophage polarization through the miR-21–5p/Smad2 axis, and the microenvironment of M2 macrophages could further promote the osteogenic differentiation of BMSCs. The findings presented in this work offer valuable insights into the molecular mechanisms that regulate bone regeneration in BMSCs and the role of macrophages in this process.

Preparation and characterization of Al-12Si/ceramic composite phase change heat storage material

Preparation and characterization of Al-12Si/ceramic composite phase change heat storage material

Enhancement of flame retardancy in ceramic polymer composite materials with ammonium polyphosphate/melamine cyanurate

AbstractTo enhance the flame‐retardant characteristics of ceramifiable polyethylene (PE) composites, a composite flame retardant comprising ammonium polyphosphate (APP) and melamine cyanurate (MCA) was integrated. This addition markedly bolstered their flame‐retardant attributes. A meticulous exploration was conducted to ascertain the impacts of APP and MCA on the ceramifiable PE composites' visible morphology, mechanical robustness, and dimensional constancy, and to study the phase transition and microstructure deformation during sintering. Findings underscored that the amalgamation of APP/MCA markedly enhanced the flame resistance of these ceramifiable composites, registering a limiting oxygen index of 25.6% and achieving the vertical burning test (UL‐94) rating of V‐0. The collaborative flame‐retardant action of APP/MCA significantly enhanced the flame resistance of the PE composites while effectively mitigating the composite's propensity to drip. Upon detailed phase analysis, a eutectic reaction was observed between APP and wollastonite fiber, culminating in the genesis of a novel crystalline phase, calcium pyrophosphate (Ca2P2O7). When subjected to elevated temperatures, glass–ceramics manifest with both crystalline and vitreous phases. The proportion of the vitreous phase plays a pivotal role in influencing the ceramic's overall performance.

Hydraulic pressure resistance of the ceramic resin composite buoyancy materials based on cylindrical tube configuration

Due to high modulus, high strength and low water absorption of the 99.5% alumina ceramic, the tubular ceramic resin composite (TCRC) has been designed and fabricated, which can provide a potential option for the deep-sea buoyancy materials. The reliability and applicability of TCRC under hydrostatic pressure are systematically discussed by means of theory, experiment and simulation. Circumferential instability and strength failure are two possible failure modes of the TCRC through theoretical analysis. The study indicates that the load-bearing capacity of TCRC decreases with the increase of the number of vertical/horizontal tube arrays m, the ratio of the inner to outer radius r/Rc of the ceramic tube or the ratio of the length to the outer radius L/Rc of the ceramic tube. Conversely, the load-bearing capacity of TCRC increases with the increase in the modulus of matrix phase Er. In addition, TCRC with parameters of “r/R-0.93/0.91-3X3-L40-E3.18” has excellent performance through experimental verification. That is, the core density and hydrostatic strength of the TCRC are 0.67 g/cm3 and 150.6 MPa, respectively. Better stated, our designed buoyancy material can be applied in the deep-sea environment of 12000m, which is the deepest spot on the ocean floor ever explored. The excellent performance of TCRC verifies the feasibility of ceramic circular honeycomb configuration in the application of hydrostatic pressure environment. Meanwhile, the buoyancy materials used in different water depths can be designed by changing the L/Rc or r/Rc of the round tube in circular honeycomb.

Effect of applied load on wear of microwave sintered alumina-graphene ceramic composite material

The present work is mainly focussed on the preparation of alumina ceramic composite material reinforced with different weight proportions (wt%) of graphene ranging from 0.15 wt% to 0.45 wt% (with an interval of 0.1) and fabrication using microwave sintering method. Wear studies are performed on graphene reinforced alumina ceramic material samples using pin-on-disk apparatus at different loads of 5 N, 10 N, 15 N keeping speed of 0.8 m s−1 and sliding distance of 40 m constant. The obtained wear results are compared with wear performance of pure alumina samples which are prepared in the same condition. Wear tests even at higher load of 15 N revealed that the decrease in the wear rate of the ceramic composite samples reinforced with 0.35 wt% of grapheme is 35.14% and in the ceramic composite samples reinforced with 0.45 wt% of graphene is 34.85% when compared with the wear rate of samples prepared with pure alumina. The effect of different wt%s of graphene on wear properties of prepared ceramic composites is studied through SEM analysis, and observed that the abrasive wear phenomenon is found to be the dominant wear mechanism.

Self-Propagating High Temperature Synthesis of Composite Material Based on Zirconium and Chromum Oxide

Ceramic composite materials based on stabilized zirconium oxide were obtained by self-propagating high-temperature synthesis. Yttrium oxide was used as a stabilizing additive. The work studied the effect of the content of yttrium oxide additive on the temperature and combustion rate of the materials studied. Also, based on the results of X-ray phase analysis and scanning electron microscopy, the effect of yttrium oxide on the phase composition and microstructure of the synthesized materials was studied.

Experimental Permeability and Porosity Determination of All-Oxide Ceramic Matrix Composite Material.

This paper presents an investigation into the water permeability of an all-oxide ceramic matrix composite. To determine the parameters and characterize the water permeability of the ceramic composite material, an experimental study was carried out in which a dedicated test rig was constructed and commissioned. A total of five different configurations of composite tubes were tested. They differed in fibre roving strength, winding angle, fibre bundle arrangement during winding, and matrix grain size distribution. To better understand the internal structure of the analysed ceramic matrix composite material, the experimental study used scanning electron microscopy for microstructure and porosity observation. The tested tubes will be used as liners in an oxy-combustion chamber in future studies. The experiments obtained new and interesting results regarding the water permeability of the ceramic matrix composite with different structural parameters. It was also observed that, as with some porous materials, the permeability of ceramic matrix composites decreases with time as more and more liquid is pressed through it.

Molecular insights into thermal conductivity enhancement and interfacial heat transfer of molten salt/porous ceramic skeleton composite phase change materials

Molten salt has been considered as one of the most promising candidate materials for thermal energy storage (TES) systems owing to its remarkable energy density and consistent thermal performance. These properties render it particularly advantageous for the applications in concentrated solar power (CSP) and industrial process heat utilization. Nonetheless, their practical applications still face nonnegligible challenges such as the low thermal conductivity and risk of leakage. Packing molten salts into porous skeletons could be an effective way for addressing these issues. In the present work, the heat transfer characteristics of a composite phase change material (CPCM) consisting of binary chloride salt and a porous ceramic skeleton, are investigated at the microscale level using molecular dynamics (MD) simulations. Simulation results indicate that the integration of a porous SiC skeleton can substantially enhance the thermal conductivity of binary molten salt NaCl/KCl. At the temperature of 1000 K, a notable enhancement of 625.74 % in thermal conductivity has been observed. Moreover, the underlying mechanism of heat conduction enhancement has been revealed from the microscopic perspective. The results demonstrate that auxiliary thermal conductivity paths and interfacial heat transfer play primary roles in determining the thermal conductivity of CPCMs. The method of surface charge modification can effectively improve the interfacial heat transfer and the reason can be attributed to the additional thermal conductivity paths and the large number of particles involved in the interfacial heat transfer. The results gained in this work may provide insights into the heat transfer mechanism of composite molten salt/porous skeleton as well as practical guidance for designing CPCM for thermal storage applications.

Preparation of WC@graphene reinforced titanium diboride‐based composite ceramic materials fabricated via SPS

AbstractLiquid‐phase laser irradiation technology was utilized to synthesize graphene‐coated tungsten carbide (WC@G) core–shell composite materials with regular spherical morphology. Characterization via scanning electron microscopy, transmission electron microscopy (TEM), X‐ray diffraction, and Raman spectroscopy revealed the evolution of WC particle microstructure from sharp edges to regular spherical shapes post‐laser irradiation. High‐resolution TEM displayed a tightly knit core–shell structure. Raman spectroscopy confirmed graphene presence through D, G, and 2D peaks. Incorporation of WC@G into a titanium diboride matrix, followed by discharge plasma sintering, yielded TiB2/WC@G composite ceramic materials. Compared to TiB2/WC/G composite ceramic materials, the WC@G core–shell structure significantly enhanced sintering performance. Optimal mechanical properties were achieved with 6 wt.% WC@G, exhibiting a relative density of 99.6%, Vickers hardness of 18.5 GPa, flexural strength of 696.9 MPa, and fracture toughness of 8.5 MPa m1/2. Characterization identified graphene detachment, pull‐out, and fracture deflection as key mechanisms enhancing toughness in TiB2/WC@G composite ceramic materials.

Polymer-ceramic composites for fused deposition modeling of biomimetic bone scaffolds

Current surgical treatments for segmental bone loss do not reliably result in healing, typically necessitate multiple surgeries, and may result in amputation. Although we have demonstrated that polybutylene terephthalate (PBT) scaffolds can regenerate large critical size bone defects, the material is non-resorbable and may lead to problems including acting as a nidus for infection. New strategies have emerged that use resorbable polymers, ceramics, and composite materials to produce patient specific scaffolds that stimulate rapid bone formation without retention of foreign material. This work describes the production of a composite polymer ceramic material composed of polylactic acid (PLA) and tricalcium phosphate (TCP) that can be used with additive manufacturing techniques to rapidly produce scaffolds with custom geometries. The technique we describe can be used to produce composite materials with a ratio of up to 50-50 PLA-TCP that is suitable for fused deposition modeling and does not necessitate the use of solvents. In this study the properties of PBT, PLA, 75-25 PLA-TCP, and 50-50 PLA-TCP materials are compared. PLA and PLA-TCP materials had a higher compressive elastic modulus compared to PBT, while composite PLA-TCP materials had a higher tensile elastic modulus compared to PLA and PBT. Cell culture experiments demonstrated that all materials were non-toxic to cells. Optimal printing parameters are provided for using pure polymer and composite materials for fused deposition modeling. The results of this study demonstrate that resorbable polymer ceramic materials with a high ceramic composition can be produced for additive manufacturing without necessitating solvents.

Recycling and reuse of ceramic materials from components of waste solid oxide cells (SOCs)

As one of the main waste streams of the manufacturing process of solid oxide cells (SOCs), scrap half-cells - discarded before the deposition of the barrier layer and the air electrode - imply the loss of significant quantities of ceramic composite material containing critical and hazardous elements, namely yttria-stabilized zirconia (YSZ) and NiO. These materials represent more than 90 wt% of an entire anode-supported cell. In this contribution, scrap half-cells were fragmented and subjected to three subsequent milling and sieving (below 25 μm) steps to recover composite NiO-YSZ powders with the appropriate specifications for reuse in SOC manufacturing. The overall characterization in terms of specific surface area, particle size distribution and crystalline phase retention confirmed the suitability of the recovered powders. Half-cells were manufactured including 30 wt% of recovered NiO-YSZ composite powders in their fuel electrode support, produced via tape-casting in combination with 70 wt% of virgin materials. The obtained cells were morphologically, mechanically and electrochemically tested and compared against standard cells constituted by 100 wt% of virgin materials. The electrochemical characterization highlighted 0.68 A cm−2 for the standard and recycled cells, at 600 °C and 0.7 V, while at 650 °C and same voltage both cells measured 1.12 A cm−2. This demonstrates the feasibility of recovering scrap SOCs through the presented method.

Insights into the fracture properties of recycled ceramic and rubber composite cement-based materials: Fracture mechanics, acoustic emission, and digital image correlation

Recycling plays a pivotal role in construction waste management, offering a path toward sustainability for the industry. Although waste ceramics can compensate for the mechanical properties of rubberized cement-based materials, the smooth glaze surface of waste ceramics increases the risk of brittle failure. This study investigated the effect of ceramic waste aggregate (CWA) on the fracture properties of rubberized mortar through the three-point bending experiment. The fracture parameters were calculated using the Double-K fracture criterion. Simultaneously, acoustic emission (AE) and digital image correlation (DIC) technologies were used to explore the fracture damage mechanism and the crack evolution process. The results indicate that the integration of 15 % and 45 % CWA significantly enhances both initiation (KICini) and unstable (KICun) fracture toughness, whereas incorporating 90 % CWA leads to a 16.8 % and 8.2 % decrease in (KICini)and (KICun), respectively. The fracture energy (GF) of rubberized mortar exhibits a continuous decline as a function of increasing CWA substitution rates. Furthermore, GMM-based RA-AF analysis elucidates a positive correlation between CWA content and tensile crack proportion in specimens. When the CWA content reaches 90 %, the proportion of tensile cracks is quantified at 29.83 %, surpassing that in standard mortar. Crack tip opening displacement (CTOD) at 0.5post-Pmax for specimens with 15 %, 45 %, and 90 % CWA substitution reveal improvements of 49.1 % and 17.2 %, and a decrease of 23.3 %, respectively, compared to standard mortar, indicating that 15 % and 45 % CWA effectively preserve the ductility of rubberized mortar. Elevated CWA substitution leads to an amplified strain localization phenomenon around the crack tip, heightening the propensity for brittle failure.