Powder Mixtures Research Articles

Enhanced synthesis of sponge-type multiwalled carbon nanotubes using SiO2-Fe2O3 catalysts via aerosol-assisted chemical vapor deposition: Electrochemical and absorption capacity studies

Carbon nanotube sponges synthesized at the laboratory scale typically use a Fe-based organometallic catalyst, but low-cost alternatives with a higher yield ratio are needed for large-scale production. This work introduces a catalyst made from a mixture of silicon dioxide (SiO2) and hematite (Fe2O3) as an innovative alternative for the high-yield production of spongy-type multi-walled carbon nanotubes (ST-MWCNTs). We used a ball-milled mixture of SiO2 and Fe2O3 powders as the catalyst and toluene and N, N-dimethylformamide as carbon and nitrogen sources in an aerosol-assisted catalytic chemical vapor deposition system. Incorporating SiO2 into the Fe-based catalyst increased production yield to 184 % of the catalyst weight. The synthesized ST-MWCNTs exhibited a high crystallinity ratio (ID/IG = 0.34) with a unique entangled bundle-type nanotube configuration. At the same time, the presence of Si atoms and oxygen-type functionalities, demonstrated by X-ray photoelectron spectroscopy, modified their electrochemical behavior, making them suitable for supercapacitor or sensor applications. Additionally, the spongy structure demonstrated a reversible absorption capacity of over 15 times its weight with organic solvents like gasoline or ethylene glycol. This new catalyst configuration opens alternatives for generating higher amounts of 3D carbon nanomaterials with potential energy storage, water filtration, and environmental remediation applications.

Exploring co-processing strategies for multi-material spark plasma sintering of pure Cu with AlSi10Mg by master sintering curves

Manufacturing complex multi-material metallic components without assembly operations is currently being explored using novel additive manufacturing techniques. For materials combinations that are difficult to process via melting-based processes, multi-material spark plasma sintering (SPS) appears as a promising alternative. However, due to different sintering kinetics, materials with very different melting points might have to be co-sintered at non-optimal conditions. In this work, the potential to improve the co-sinterability of dissimilar materials, namely pure copper and AlSi10Mg, is evaluated by altering the sintering kinetics of copper using different particle size distributions (PSD). Using the master sintering curve (MSC) approach, the densification behaviour of spherical pure copper powder during SPS is evaluated systematically to study the influence of PSD, uniaxial applied pressure, and isothermal holding temperature. An intermediate-sized monomodal and close-to-optimal bimodal PSD are compared for processing at lower sintering temperatures. It was observed that, compared to an intermediate monomodal PSD, a near-optimal bimodal powder mixture yields fully dense Cu–AlSi10Mg components at lower temperature and shorter process times. Therefore, the use of a bimodal mixture enables multi-material sintering, offers energy and cost savings to produce multi-material components, and improves compatibility between materials with very different melting points.

МИКРОСТРУКТУРА И ФАЗОВЫЙ СОСТАВ МАТЕРИАЛОВ СИСТЕМЫ «ТИТАН-ЖЕЛЕЗО», ПОЛУЧЕННЫХ ВЗРЫВНЫМ ПРЕССОВАНИЕМ И РЕАКЦИОННЫМ СПЕКАНИЕМ

The results of a study of the influence of modes of explosive pressing of powder mixtures of titanium and iron and reaction sintering of compacts on the phase composition and structure of materials of the Fe-Ti system are presented. It has been shown that the use of 71 at. % Ti and accelerated cooling after sintering makes it possible to obtain a material consisting almost entirely of the intermetallic compound Ti2Fe.

Yacon powder mix: Effects of the composition and the process of microencapsulation by spray drying

Yacon is a tuber known as a healthy food due to its effects as an antidiabetic, anti-inflammatory, anticancer, and prebiotic agent; it is rich in fructooligosaccharides (FOS) and antioxidants, and due to its sweet taste and low-calorie content, it is used as a substitute for ordinary sugar. This research aimed to evaluate the influence of the composition of the feed and the microencapsulation process by spray drying (SD) on the properties of a yacon powder mixture (YP). Response surface methodology with a central composite design with a face-centered composition (α = 1) was used, considering the independent variables: inulin (IN) (3–5% w/w), maltodextrin (MD) (3–5% w/w), air inlet temperature (AIT) (140–160 °C), air outlet temperature (AOT) (75–85 °C) and atomizer disc speed (ADS) (18000–22000 rpm), and the dependent variables: moisture (Xw), water activity (aw), hygroscopicity (Hy), solubility (S), particle size (percentile D10, D50, and D90), total phenols (TP), antioxidant capacity (ABTS and DPPH), color (CIE-Lab*) and yield (Yi). The suspension formulation contained xanthan gum (0.167 %) and a mixture of ascorbic and citric acids (0.3 %). The aw and Xw values of the YP guarantee its microbiological stability; however, the process formulation produces a complex matrix (FOS- sugars- MD - IN) with high affinity for water, which favors adsorption phenomena (hygroscopic material) and high reconstitution (high solubility). The independent variables that best fit the experimental optimization criteria were: IN = 3.0 %, MD = 5.0 %, AIT = 143.7 °C, AOT = 80.1 °C, ADS = 22000 rpm, where Yi = 84.2 %, and the quality of the YP: Xw = 2.4 %, aw = 0.220, Hy = 23.0 %, S = 96.9 %, D10 = 10.6 μm, D50 = 23.4 μm and D90 = 169.3 μm, TP = 1228.2 mg gallic acid equivalent/100 g, ABTS = 2295.9 mg Trolox equivalent (TE)/100 g, DPPH = 5192.3 mg TE/100 g, L* = 80.5, a* = 5.1 and b* = 17.4. SD is an effective technology that positively impacts the development of new food products. In addition, the YP could have multipurpose applications for the industry, generating value in this agri-chain.

Fabrication of Titanium Alloy-Based Composite Materials from Bimodal Powder Mixtures Ti–6Al–4V–(Cu–Al) by Direct Selective Laser Melting

Fabrication of Titanium Alloy-Based Composite Materials from Bimodal Powder Mixtures Ti–6Al–4V–(Cu–Al) by Direct Selective Laser Melting

Carcass Characteristics, Meat Antioxidative State, and Gut Microbiota of Broilers Fed With a Mixture of Bitter Melon and Basil Leaves Powder

The impact of a mixture of bitter melon leaf and basil leaf powder (BBLPB) on the carcass characteristics, meat antioxidant state, and gut microbiota of broilers was investigated. Three hundred one-day-old Cobb 500 broiler chicks were allocated to five diets: diet 1 (negative control), diet 2 (positive control; 0.1% blend of probiotic, prebiotic, and acidifier (BPPA) supplementation), diets 3 (0.25% BBLPB), 4 (0.5% BBLPB), and 5 (0.75% BBLPB) randomly. The 0.25% BBLPB supplementation improved (P < 0.05) slaughtered weight, dressed weight, dressing %, and growth rate of broilers, while organ weights remained unchanged (P > 0.05). Slaughtered weight recorded in diets 2 and 3 was higher (P

Fabrication of high speed steel electrodes with MoSi2–MoB–HfB2 ceramic additives for electrospark deposition on die steel

The electrodes for electrospark deposition (ESD) were fabricated from hot-pressed blanks composed of a mechanically alloyed powder mixture of R6M5K5 high speed steel. This mixture was enriched with a 40 % addition of heat-resistant MoSi2–MoB–HfB2 ceramics, produces through the self-propagating high-temperature synthesis method (resulting in the R6M5K5-K electrode), as well as variant without any ceramic addition (resulting in the R6M5K5 electrode). We examined both the composition and structure of the electrode materials and the coatings derived from them, identifying the characteristics of mass transfer from hot-pressed electrodes to substrates of 5KhNM die steel under various frequencies and energy conditions during processing. The R6M5K5 electrode consists of an α-Fe-based matrix incorporating dissolved alloying elements and contains discrete particles of ferrovanadium, tungsten carbide, and molybdenum. The R6M5K5-K electrode, in addition to the α-Fe-based matrix, includes borides and carbides, as well as hafnium oxide. The use of the R6M5K5 electrode resulted in a consistent weight increase in the cathode throughout the entire 10-minute processing period. In contrast, the application of the ceramicenhanced electrode led to weight gain only during the initial 3 min of processing. Subsequently, ESD produced coatings of 22 and 50 μm thickness on the surface of 5KhNM steel using R6M5K5 and R6M5K5-K electrodes, respectively. The introduction of SHS ceramics escalated the roughness (Ra) of the surface layers from 6 to 13 μm and the hardness from 9.1 to 15.8 GPa. The coating from the R6M5K5 electrode was composed of austenite (γ-Fe) and exhibited high uniformity. Conversely, the coating from the R6M5K5-K electrode consisted of a diverse matrix with both crystalline and amorphous iron, an amorphous phase rooted in the Fe–B alloy, and scattered phases of HfO2, HfSiO4, Fe3Si, and Fe3B. High-temperature tribological testing at 500 °C in an air atmosphere showed that the coatings possess a friction coefficient of 0.55–0.57 when coupled with a counterbody of AISI 440C steel. The integration of heat-resistant ceramics notably enhanced the coating's wear resistance, increasing it by a factor of 13.5.

Защита деталей горного оборудования, работающих в условиях подземных выработок от биокоррозии

Introduction. Biological corrosion of mining equipment parts is an important problem. Ti-Cu-based coatings provide effective protection against such corrosion. A significant number of mining equipment parts operate under conditions of intense wear. These are parts such as pins, rollers, gears, racks, drive stars, etc. When applying a coating to such parts, it is important not only to increase the anti-corrosion properties, but also to maintain or improve the tribological properties of the parts being processed. The use of coatings based on metal oxides is an effective tool to combat bio corrosion. Among such metal oxides, nanocomposites that include a combination of TiO2 and Cu2O have performed best. These composites have a narrow bandgap, chemical stability and low toxicity. However, the issue of their influence on the tribological properties of parts remains incompletely studied. The purpose of this work is to analyze the structural features, mechanical properties and wear resistance of the Ti-TiO2-Cu-Cu2O coating applied by detonation spraying. Materials and methods. In this work, Ti-TiO2-Cu-Cu2O composite coatings were formed on a steel substrate. Sputtering was carried out using a multi-chamber detonation accelerator system. The coating process was carried out layer by layer using a device that moved back and forth with a lateral displacement. Titanium (PTN-8VT10) and copper (PMS-1) powders were used as raw materials. Wear tests were carried out using a disk-pin design. X-ray structural analysis was carried out for the obtained samples, and the microstructure of the coatings was studied. The micro hardness of the applied coating was also determined. Results. In the resulting coatings between the two elements Ti and Cu of the deposited powders, no chemical reaction or intermetallic compounds were detected. Ti-TiO2-Cu-Cu2O composite coatings mainly consisted of TiO2 and Cu2O, with titanium and copper acting as a binder, providing a high density of the composite material. Distinct formations of metallic Ti and Cu particles are observed in various regions of the microstructure, with many formations of metallic Ti retaining their spherical shape. The Ti-TiO2-Cu-Cu2O coating has a high average hardness of 640 HV0.2. The coefficient of friction when the Al2O3 counter body slides over the coating after a short running-in cycle did not change and amounted to 0.38. Discussion. The analysis of the cross section revealed that the coating material has a dense structure, characterized by strong inter lamellar-type connections, and has no signs of destruction or cracks. The absence of cracks and delamination along the boundary between the substrate and the coating indicates the high quality of adhesion to the base. The thickness of this composite coating is approximately 340 ± 20 micrometers. The increased hardness of this coating can be explained by the partial melting and rapid solidification of powder particles during spraying, as well as its lamella-type compositional structure. The micro hardness profile inside the Ti-TiO2-Cu-Cu2O coating remains uniform. During tribo-technical tests with a 100Cr6 counter body, the friction coefficient of the tribo couple after running-in decreased as the sliding cycles increased. This effect is due to the formation of a tribo layer on the worn surface of the coating, which serves as protection against severe wear. These conditions prevent the counter body from sticking to the coating surface, which reduces the likelihood of adhesive wear. The main composition of the sealing tribo layer is iron oxide, formed as a result of an increase in temperature on the sliding surface and wear of the steel counter body during dry sliding, which prevents adhesion in contact. Conclusions. The authors conclude that during the spraying of a Ti-Cu powder mixture, ceramic reinforcement is formed, where titanium and copper, interacting with atmospheric components at the time of spraying, are capable of forming new oxide phases. Due to the absorption of oxygen by titanium and copper during the deposition process, the resulting composite acquires an average micro hardness of 640 HV0.2. The analysis of the cross-section of the coating revealed that the coating has a thickness of about 300 microns, has a dense structure characterized by strong interlamellar-type connections, and has no signs of destruction or cracks. Resume. The results obtained show that Ti-TiO2-Cu-Cu2O coatings applied to critical parts of mining equipment not only protect them from bio-corrosion, but also increase tribological properties. This allows you to increase the maintenance-free service life of equipment in mining operations. Suggestions for practical applications and future research directions. Ti-Cu composite coatings obtained by detonation thermal spraying can be used for such parts of mining equipment as pins, rollers, gears, racks, drive stars, etc. These coatings can be used not only to protect mechanisms and structural elements in mining conditions, but also for equipment elements operating in humid climates.

Hard Gelatin Capsules with Alginate-Hypromellose Microparticles as a Multicompartment Drug Delivery System for Sustained Posaconazole Release.

Microparticles as a multicompartment drug delivery system are beneficial for poorly soluble drugs. Mucoadhesive polymers applied in microparticle technology prolong the contact of the drug with the mucosa surface enhancing drug bioavailability and extending drug activity. Sodium alginate (ALG) and hydroxypropyl methylcellulose (hypromellose, HPMC) are polymers of a natural or semi-synthetic origin, respectively. They are characterized by mucoadhesive properties and are applied in microparticle technology. Spray drying is a technology employed in microparticle preparation, consisting of the atomization of liquid in a stream of gas. In this study, the pharmaceutical properties of spray-dried ALG/HPMC microparticles with posaconazole were compared with the properties of physical mixtures of powders with equal qualitative and quantitative compositions. Posaconazole (POS) as a relatively novel antifungal was utilized as a model poorly water-soluble drug, and hard gelatin capsules were applied as a reservoir for designed formulations. A release study in 0.1 M HCl showed significantly prolonged POS release from microparticles compared to a mixture of powders. Such a relationship was not followed in simulated vaginal fluid (SVF). Microparticles were also characterized by stronger mucoadhesive properties, an increased swelling ratio, and prolonged residence time compared to physical mixtures of powders. The obtained results indicated that the pharmaceutical properties of hard gelatin capsules filled with microparticles were significantly different from hard gelatin capsules with mixtures of powders.

Photothermally responsive graphene hybrid dry powders for diabetic wound healing

The treatment of diabetic wounds remains a significant challenge in the medical field. In this study, we present a novel approach using photothermally responsive graphene hybrid dry powders for the treatment of diabetic wounds. These powders, derived from polyacrylic acid (PAA) and polyethyleneimine (PEI), exhibit rapid water absorption at the interface, leading to the in situ formation of physically crosslinked hydrogels due to interactions between polymers. Furthermore, by incorporating graphene into the PAA/PEI powder mixture, we establish a multifunctional platform with capabilities such as photothermal antibacterial effects and drug release. Given the outstanding performance of this hybrid material, we demonstrate its potential in wound healing by incorporating the tumor necrosis factor-alpha (TNF-α) inhibitor Etanercept into the PAA/PEI powder. This intervention resulted in a significant improvement in the wound healing process in diabetic rats, as evidenced by the downregulation of inflammatory factors, promotion of collagen deposition, and enhanced vascularization. These remarkable attributes underscore the enormous potential value of the presented hydrogel patches in the field of biomedicine.

Wear-Resistant Low-friction Atmospheric Pressure Plasma Spray Coatings for Sustainable (Bio-based Recyclable) Materials

Coatings from polyetheretherketone (PEEK), polyamide 12 (PA12), molybdenumdisulfide (MoS2), zinc (Zn), and graphite (C) powder mixtures were deposited on PA6, PA12, and PEEK substrates by an atmospheric pressure plasma (APP) spray jet system. Several tenth of µm thick coatings on PA6 and PA12 substrates result in an almost halved surface roughness Ra ~8 µm, Rq ~10 µm and Rz ~60 µm, whereas a significant increase of all surface roughness parameters is observed for PEEK substrates (Ra < 1 µm → 4 µm, Rq < 1 µm → 5 µm, Rz < 5 µm → 20 µm). The surface roughness, powder composition, and selected APP process parameter strongly influence the coefficient of friction (COF) and specific wear rate ki of the APP coatings in rotational ball-on-disc tribological testing. The COF of PA12/MoS2/C coatings on PA6 substrates manufactured by selective laser sintering (SLS) is ~0.2 after 628 m sliding distance, resulting in a very low calculated ki of 6.3 × 10−7 mm3/Nm. A similarly low COF and ki was observed for PEEK coatings deposited at a current of 75 A and 60 mm jet–substrate distance on SLS PA12 substrate. Although the COF of Zn/C/MoS2 coatings on PEEK drops down below 0.1 after 1884 m sliding distance under nitrogen atmosphere the corresponding ki of 5.6 × 10−5 mm3/Nm is higher. Still all calculated specific wear rates are significantly lower than the reported values of polyamide-polytetrafluorethylene (PTFE)-polyethylene composites (1.9–8.0 × 10−2 mm3/Nm) and partly even outperform PEEK-PTFE composites (1.0 × 10−7–2.5 × 10−6), currently applied in demanding wear regimes.

Enhanced properties of ZrSiO4/ZrO2 composites produced by colloidal processing and spark plasma sintering

Zirconium oxide and silicate are well-known reference materials in ceramics. However, the performance of zircon/zirconia composites has not received the required attention considering the interesting properties and capabilities. Zircon and zircon/zirconia suspensions were optimised by colloidal processing routes. These suspensions were either slip cast to obtain pieces that were conventionally sintered or freeze-dried to obtain homogeneous powder mixtures for consolidation by non-conventional Spark Plasma Sintering (SPS). Pure zircon materials with densities up to 97.0 % and a hardness of 10.1 GPa were obtained by conventional sintering (1550 ºC/120 min) whereas densities higher than 99.5 % and hardness up to 12.7 GPa were achieved by SPS (1500 ºC/5 min). By introducing 20 vol.% zirconia as a sintering additive, densities up to 99.3 % and a hardness of 11.1 GPa were achieved by conventional sintering (1500 ºC/120 min) whereas densities of 99.9 % and a hardness of 13.5 GPa were obtained by SPS (1400 ºC/5 min).

Intercalation based synthesis of Chevrel phase superconductors

This work focuses on the superconducting and magnetic properties of Chevrel phase (CP) compounds (Cu2Mo6S8 and Ni2Mo6S8) processed via a novel self-propagating high-temperature synthesis (SHS) method involving ternary cation intercalation in MoS2 high-temperature polymorphs. Green pellets of the precursor materials sealed under vacuum and exposed to 1050 °C or 1200 °C rapidly transformed from a powder mixture into submicron CPs within minutes. X-ray diffraction analysis confirmed the presence of Cu2Mo6S8 CP (67%), and Ni2Mo6S8 (93%). This group has illustrated the first time CP were formed at low energy cost and full stoichiometry. Magnetization versus temperature data obtained for the samples under different field conditions confirmed the superconducting behavior of the Cu–CP at a critical temperature of 8.3 K. The Ni–CP behaved as a superparamagnetic at low temperature (4.2 K). The results of this work suggest that the novel SHS process offers a viable scalable synthesis route for the Chevrel family of compounds and that it is worth exploring the functional applications of the new compounds of this material system.

Formulation, design, and evaluation of valsartan sodium-sustained-release matrix tablets

The main aim of present work was to formulate and evaluate sustain release matrix tablets of Valsartan, an angiotensin II Receptor type 1 antagonist. Sustain release formulation are those which delivers the drug locally or systemically at a predetermined rate for a fixed period of time. The matrix tablet was prepared by direct compression method using by various concentration of chitosan and sodium alginate with combination of various release retardant polymer. The powder mixtures were subjected to various pre-compression parameters such as angle of repose, bulk density, tapped density and Carr’s index shows satisfactory result and the compressed tablets are evaluated for post-compression parameters such as weight variation, thickness, hardness, friability, drug content, in-vitro dissolution and stability studies. In-vitro dissolution studies were carried out for 24 hours using 0.1N HCl for first 2 hours and pH 6.8 phosphate buffers for 24 hours and the result showed that formulations F4 and F7 showed good dissolution profile to control the drug release respectively. Formulation containing higher concentration of chitosan and sodium alginate along with polymers sustainedthedrugreleasefor theperiodof24hours.The compatibilityof thedrug, polymers and other excipients were determined by FT-IR Spectroscopy. Results showed that the drug was compatible with polymers and other excipients. The release data was fitted to various mathematical models such as Zero-order, First-order, Higuchi equation and Korsmeyer- Peppas model to evaluate the kinetics and the drug release. The drug release followed first order and the mechanism was found to be non-Fickian. The stability studies were carried out for 3 months and result indicates that the selected formulations (F4and F7) were stable.

Hydrogen Reduction Behavior and Microstructure Characteristics of WO3-NiO-CuO Powder Mixture

The characteristics and hydrogen reduction behavior of W-0.8 wt% Ni-0.4 wt% Cu powder synthesized from WO3-NiOCuO composite powder have been investigated. The metal oxide powder mixtures were prepared using a ball milling process. XRD analysis and HR-TEM revealed that the oxide powders are changed to W and CuNi alloy powders with an average particle size of about 100 nm by hydrogen reduction. To understand the reduction behavior of oxide powders, TG analysis was performed, and the reduction kinetics was evaluated by the amount of peak shift with heating rates. The activation energies for the reduction of WO3-NiO-CuO, estimated by the slope of the Kissinger plot, were measured as 60.6-114.4 kJ/mol depending on reduction steps.

Random walk characteristics of particles in slurry pipeline transportation

During the pumping of wet shotcrete in a pipe, the aggregate migrates under various forces. In order to investigate the random walking characteristics of particles in slurry pipeline transportation, particle tracking platform for half-open tubes was constructed. Cement-like slurry colloids were prepared. The particle capture function of high-speed camera was utilized to track the particle movement. Random walk theory was used to analyze the transport trajectories of aggregates with different particle sizes. The transport properties of the particles were quantitatively analyzed. The experimental results showed that cement-like slurry colloids were obtained by using a mixture of powder of xanthan gum, carbomer, polyacrylamide and water mixed in a certain proportion. The trajectory of particle transportation in the slurry pipe had a large correlation with the particle size. In a straight pipe, the smoothest particle trajectories were found in the range of 4.17–6.25 % of the pipe diameter. The spectral dimension was positively correlated with tortuosity and more highly correlated with particle size in pipeline transport. The number of spectral dimensions and tortuosity were negatively correlated with axial walking steps of the particles. This paper provided a new way of thinking to study the particle transportation law in concrete pipeline.

Electromagnetic characterization of MAX phase and MXene in Ti–Al–C ternary system

The present paper set out to investigate the synthesis and electromagnetic characterization of Ti3AlC2 MAX phase and Ti3C2Tx MXene in Ti–Al–C ternary system. In this regard, Ti3AlC2 MAX phase was synthesized using mechanical milling process of TiC, Al, and Ti powder mixtures based on 2TiC–Al–Ti + xAl (x = 0, 0.25, 0.5, 0.75 and 1). The HF acidic etching was also employed to synthesize the Ti3C2Tx MXene. Structural and electromagnetic characterizations of the prepared samples were conducted using X-ray diffraction (XRD), scanning electron microscopy (SEM) and vector network analyzer. The obtained results point to the impossibility of the formation of Ti3AlC2 single-phase structure in stoichiometric system. In other word, development of the Ti3AlC2 single-phase structure is only possible in non-stoichiometric 2TiC–2Al–Ti system. The minimum reflection losses of the prepared Ti3AlC2 MAX phase was estimated to be around −30.73 dB at the matching frequency of 15.25 GHz. The results further revealed that the etching time affects electromagnetic behavior of the MXene. That is, an increase in the etching time brings about a change in the reflection loss (RL) from −24.17 to −5.69 dB within the frequency range of 1–18 GHz.

Microstructure Analysis and Powder Bed Fusion of Inconel 738 Powder Materials Mixed with Nano-Sized Ceramic Powders

Powder materials strengthened by oxide dispersion are generally made by in-situ method; direct oxide dispersing in matrix powders during atomization. There is also ex-situ method; oxides dispersing by mixing with matrix powders. In this study powder mixtures (Inconel 738 matrix powder + SiO2 powder + Al2O3 powder) were mechanically manufactured by ex-situ process, a lowenergy ball milling method. Then, specimens of the as-mill powders were manufactured by laser powder bed fusion (L-PBF) method and spark plasma sintering (SPS) process. The microstructures of each prepared specimen were compared according to process variables. SEM, EDS, XRD, and Electron Backscatter Diffraction (EBSD) analyses were applied in this study.

Advanced Dentistry Biomaterials Containing Graphene Oxide.

The aim of this study was to obtain three experimental resin-based cements containing GO and HA-Ag for posterior restorations. The samples (S0, S1, and S2) shared the same polymer matrix (BisGMA, TEGDMA) and powder mixture (bioglass (La2O3 and Sr-Zr), quartz, GO, and HA-Ag), with different percentages of graphene oxide (0%, 0.1%, 0.2% GO) and silver-doped hydroxyapatite (10%, 9.9%, 9.8% HA-Ag). The physical-chemical properties (water absorption, degree of conversion), mechanical properties (DTS, CS, FS), structural properties (SEM, AFM), and antibacterial properties (Staphylococcus aureus, Enterococcus faecalis, Streptococcus mutans, Porphyromonas gingivalis, and Escherichia coli) were investigated. The results showed that the mechanical properties, except for the diametral tensile test, increased with the rise in the %GO. After 28 days, water absorption increased with the rise in the %GO. The surface structure of the samples did not show major changes after water absorption for 28 days. The antibacterial effects varied depending on the samples and bacterial strains tested. After increasing the %GO and decreasing the %HA-Ag, we observed a more pronounced antibacterial effect. The presence of GO, even in very small percentages, improved the properties of the tested experimental cements.

Seashell powder calcined slag cement: A novel green low-carbon ternary cement

To reduce the carbon dioxide emissions during cement production, this research utilized seashell powder and calcined slag to replace a portion of the cement clinker, creating a novel green, low-carbon, ternary cement—seashell powder calcined slag cement (SCSC). This study investigated the impacts of seashell powder and calcined slag on the mechanical properties, hydration process, and microstructure of SCSC. The findings revealed that the addition of seashell powder and calcined slag improved the material’s toughness and promoted the formation of cementitious products such as carboaluminate phases, C-A-S-H gel, and ettringite, with a 15% mixture of seashell powder and calcined slag increasing the compressive strength ratio of SCSC to ordinary Portland cement to 112%, and reducing the proportion of large pores by 3%.