One-step Sintering Method Research Articles

Carbon Dots Prepared by One-step Sintering Method and their Application for pH Detection

Introduction: In recent years carbon dots (CDs) have attracted researchers due to their unique physicochemical and fluorescent (FL) features, which can be applied in many fields such as battery materials, fluorescence sensing, display, biological imaging and photocatalysis. Method: We prepared CDs by using a facile one-step sintering method. The fluorescent properties and the application of pH detection were measured and analyzed. Results: The results show that CDs emit bright purplish-blue light centred at 425 nm excited by 355 nm UV light. FL intensity shows a linear relationship with pH values at 1~4 and 7~11, respectively. The reasonable mechanism of the tested effective pH sensitivity is discussed. Conclusion: Our study shows that the CDs prepared by the one-step sintering method have great potential to be used as pH sensors for physiochemical measurements.

The network structure and properties of a unique mining solid waste-based glass-ceramics

To alleviate the environmental pollution caused by the stockpile of mining-based, such as coal-based solid waste, mining solid waste-based CaO-MgO-Al2O3-SiO2 (CMAS) glass-ceramics with a diopside phase as the main crystalline phase was developed by one-step sintering method, and the effect of different solid waste content on the network structure and properties were investigated. The results show that, with the diversification of solid waste content, the crystallization temperature (Tp), the amount of Fe3+ concentration, and diopside crystalline, the main structure of glass Q2 changed also. Accordingly, significant changes have occurred in properties such as the bending strength, Vickers hardness, and density. Optimizing the raw material ratio, crystallization mechanism, a mining solid waste-based glass-ceramic with unique network structure is well developed and the bending strength, Vickers hardness, fracture toughness, and density reaches maximum values of 175.19 MPa, 10.47 GPa, 2.03 MPa⋅m1/2, and 3.00 g/cm3, respectively. The findings contribute significantly to the development of durable and reliable materials for the utilization of mining solid waste resources.

Two-stage repeat sintering: A modified method for fabricating hydroxyapatite scaffolds with enhanced mechano-therapeutic properties

A modified two-stage repeat sintering (TSRS) technique has been used to produce hydroxyapatite (HAp) from non-separated animal bones, and the energy consumption per cycle of the proposed TSRS was calculated. The TSRS technique was compared to the conventional one-step sintering method. The energy consumption per cycle of the proposed TSRS was calculated considering economies of scale and typical energy consumption billing in Nigeria. The synthesized powders from both techniques underwent comprehensive characterization through X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM). The XRD analysis revealed the main reflections of HAp in the (112), (300), and (202) planes. The FT-IR spectra exhibited characteristic bands representative of HAp at all measurement points. Notably, the TSRS-derived sample during the second sintering step showed carbonate bands, suggesting relevance in the bone structure makeup. SEM images unveiled varying crystal morphologies, ranging from irregular shapes in the raw bone (RB) sample to rounded shapes with nucleation in aggregates and agglomerates at micro and macro levels in the TSRS-derived samples. The samples obtained from the TSRS technique demonstrated a high Ca/P ratio that is potentially beneficial for osteoblast adhesion in vivo. The cost analysis of electricity consumption per TSRS cycle, factoring in economies of scale and typical energy consumption billing in Nigeria, amounted to approximately $8 with consideration of the exchange rates at the time of the study. The microhardness measured using the TSRS technique was 0.5 GPa with a 1 MPa compaction pressure, while the samples prepared using the conventional sintering method were too fragile to handle and measure. The obtained microhardness using the modified technique surpassed values reported in various studies. In conclusion, the samples produced using the TSRS technique exhibited promising results regarding energy efficiency, material characteristics, and microhardness compared to the samples produced through conventional sintering. The distinct crystal morphologies observed suggest potential advantages for biomedical applications, particularly in enhancing osteoblast adhesion.

Microstructure, Mechanical Property and Thermal Conductivity of Porous TiCO Ceramic Fabricated by In Situ Carbothermal Reduction of Phenolic Resin and Titania.

The porous TiCO ceramic was synthesized through a one-step sintering method, utilizing phenolic resin, TiO2 powder, and KCl foaming agent as raw materials. Ni(NO3)2·6H2O was incorporated as a catalyst to facilitate the carbothermal reaction between the pyrolytic carbon and TiO2 powder. The influence of Ni(NO3)2·6H2O catalyst content (0, 5, 10 wt.% of the TiO2 powder) on the microstructure, compressive strength, and thermal conductivity of the resultant porous TiCO ceramic was examined. X-ray diffraction and X-ray photoelectron spectroscopy results confirmed the formation of TiC and TiO in all samples, with an increase in the peak of TiC and a decrease in that of TiO as the Ni(NO3)2·6H2O content increased from 0% to 10%. Scanning electron microscopy results demonstrated a morphological change in the pore wall, transforming from a honeycomb-like porous structure composed of well-dispersed carbon and TiC-TiO particles to rod-shaped TiC whiskers, interconnected with each other as the catalyst content increased from 0% to 10%. Mercury intrusion porosimetry results proved a dual modal pore-size distribution of the samples, comprising nano-scale pores and micro-scale pores. The micro-scale pore size of the samples minorly changed, while the nano-scale pore size escalated from 52 nm to 138 nm as the catalyst content increased from 0 to 10%. The morphology of the pore wall and nano-scale pore size primarily influenced the compressive strength and thermal conductivity of the samples by affecting the load-bearing capability and solid heat-transfer conduction path, respectively.

Development of a novel fabrication technique for high-quality Bi-2223 bulks with high superconducting performance

The superior intergranular connectivity and strong flux pinning are indispensable for achieving high current capacity in Bi-2223 high-temperature superconductors (HTS). In contrast to the traditional one-step sintering method, a newly developed pressing extension texture enhancement (PETE) method was employed to synthesize high-quality Bi-2223 bulks with larger superconducting phase content of 98.5 % and stronger textural structure of 97.8 %. The improved superconducting quality is beneficial for optimizing carrier concentration, and high critical temperature (Tc∼ 109.4 K) has been obtained. High-resolution transmission electron microscopy (HRTEM) images further reveal the inhibition of amorphous phase and secondary phase particles at grain boundaries, along with enhanced inter-grain connections during the PETE process. The higher inter-grain Jc in 2nd Bi-2223 (Jc,inter∼77.3 A/cm2 at 97 K) compared with 1st Bi-2223 (Jc,inter∼3.68 A/cm2 at 95 K) was found. Moreover, an enhancement in intra-granular pinning force density (Fp) and a transition in the flux pinning mechanism were observed at different temperatures. And the larger intra-grain Jc (Jc, intra ∼107 A/cm2 at 4.2 K,0 T) in 2nd Bi-2223 was obtained. Our work provides a novel technique for preparing high-performance Bi-2223 superconducting bulks, establishing a solid foundation for in-depth study on Bi-2223 superconductors.

Improving the electric energy storage performance of multilayer ceramic capacitors by refining grains through a two-step sintering process

Dielectric materials for multilayer ceramic capacitors (MLCCs) have been widely used in the field of pulse power supply due to their high-power density, high-temperature resistance and fatigue resistance. However, the low energy storage density is one of most critical issues hindering their miniaturization and integration development in cutting-edge technologies. In this manuscript, Na0.5Bi0.5TiO3-based MLCCs with improved energy storage properties were fabricated via composition modification and sintering process improvement. The introduction of BiMg0.5Hf0.5O3 weakens the ferroelectricity of 0.94Na0.5Bi0.5TiO3-0.06BaTiO3, while ensures high saturation polarization, delays polarization saturation, and low residual polarization, improving energy storage efficiency. Specifically, we adopted a two-step sintering process, by which the grain size of MLCCs sintered reduces by 60 %, the dielectric breakdown field strength increases by 33 %. The energy storage density reaches 7.8 J cm−3, 77 % higher than the MLCCs fabricated by traditional one-step sintering method. Moreover, the energy storage density changes by less than 10 % in a wide temperature range of 10 ∼ 180 °C. This study confirms that two-step sintering can also be applied to the preparation of Na0.5Bi0.5TiO3-based MLCCs and provides a way to improve the energy storage performance of lead-free MLCCs, and benefits to the application of MLCCs as high voltage capacitors.

Photocatalytic degradation of sulfamethoxazole over S-scheme Fe2O3/g-C3N4 photocatalyst under visible light

The application of promising g-C3N4 has been limited by poor photogenerated electron-hole separation and limited absorption for visible light. Sulfamethoxazole (SMX) is a typical antibiotic drug that is used worldwide and hard to be disposed through conventional wastewater treatment methods. Herein, S-scheme Fe2O3/g-C3N4 heterojunction was successfully prepared via a facile one-step sintering method and applied to photodegrade SMX under visible light irradiation. The integration of Fe2O3 and g-C3N4 shows superior charge separation and light absorption ability. As a result, the removal efficiency of 11 wt% Fe2O3/g-C3N4 reaches to 99.2% within 30 min, which is visibly higher than 59.5% of pure g-C3N4. ·O2− and ·OH are demonstrated to be the predominant active species for SMX photodegradation, and the possible degradation pathway is also proposed based on electronic band structure of Fe2O3/g-C3N4 heterojunction. This study presents a facile construction of g-C3N4 based S-scheme photocatalyst and offers an environmentally friendly approach to effectively remove organic pollutants using renewable solar energy.

Preparation and properties of microcrystalline foam ceramics from silicon manganese smelting slag

In order to solve the problem of high accumulation of silicon-manganese slag, this paper proposes a method to prepare foam ceramics with high porosity using silicon-manganese slag as raw material. Two types of silicon-manganese slag were obtained from different regions of Ningxia, China, and used to prepare foam ceramics. This was done with the help of one-step sintering method by adding SiC as a foaming agent and borax as a flux. The effects of chemical composition and crystal phase difference of silicomanganese slag on the physical properties, phase and micromorphology of foam ceramics were investigated. By adjusting the firing temperature and foaming agent content, the optimal process for the preparation of foam ceramics by two kinds of silicomanganese slag was determined. The phase and microstructure of the samples were characterized by X-ray diffractometer (XRD) and scanning electron microscope (SEM), and physical analysis was carried out. The results show that when the sintering temperature of the Huiyi silica manganese slag (HYSM) sample is 1100 °C, the bulk density reaches the minimum value of 0.41 g/cm3, while the porosity and compressive strength are 86.26 % and 0.95 MPa, respectively. On the other hand, when the sintering temperature of the Tianyuan silica manganese slag (TYSM) sample is 1110 °C, the packing density reaches a value of at least 0.51 g/cm3, while the porosity and compressive strength are 80.07 % and 2.09 MPa, respectively. The XRD and SEM results show that the crystalline phase of the HYSM sample is mainly magnesium feldspar, while that of the TYSM sample is mainly diopside. In this study, two kinds of silicon manganese slag with different physical and chemical properties were used to prepare foam ceramics with high porosity, and a theoretical basis for the large-scale use of silicon manganese slag in foam ceramics was presented.

A novel approach to prepare high density SiC ceramics by powder extrusion printing (PEP) combined with one-step sintering method

High density (97 %) SiC ceramics containing in-situ synthesized Y4Al2O9 (YAM) have been successfully fabricated by a novel PEP additive manufacturing technology combined with a one-step sintering method without any post-treatments. The process of additively manufacturing SiC green body, debinding and sintering has systematically studied. Meanwhile, the atomic structure of SiC and YAM was characterized, and the mechanical properties of sintered SiC ceramics were measured. The HRTEM results revealed the crystallographic orientation relationships between YAM and SiC as (0 4 0) YAM // (1 0 1- 1) SiC and [1 0 2] YAM // [1 2¯ 1 0] SiC for the first time. The density, Vickers hardness and three-point bending strength of the sintered SiC samples are 3.11 g/cm3, 19.35 ± 0.28 GPa and 225 ± 27 MPa, respectively. Thus, PEP combined with the one-step sintering method provides a new strategy for complex-shaped SiC ceramics with high density and mechanical properties.

Multi-morphology composite: Particle & petal-shaped ZnFe2O4/flower-shaped ZnO@Porous biomass carbon with excellent broadband microwave absorption performance

Utilizing carbon and magnetic components to construct microwave-absorbing composites with broadband and strong absorption has become a research focus. Improving the structural coupling of these materials to enhance impedance matching and dielectric performance remains a significant obstacle. Particle and petal-shaped ZnFe2O4/flower-shaped ZnO@chestnut shell biomass-carbon composites (ZnFe2O4/ZnO@CBC) were synthesized via a one-step sintering method. The biomass carbon-based material presents a three-dimensional framework structure, while the particle and petal-shaped ZnFe2O4 and flower-shaped ZnO are uniformly distributed on its surface. This distribution significantly improves the dielectric polarization performance and magnetic loss of the material, ultimately leading to good microwave attenuation ability through impedance matching. Taking the addition of 1 g of biomass as an example, the minimum reflection loss (RLmin) of the composite material is −50.43 dB, and the widest effective absorption bandwidth (EAB) reaches 7.13 GHz (10.87–18 GHz). Notably, the EAB of the different composite materials all remains above 6.4 GHz when the biomass addition is adjusted within the range of 1–2.5 g, indicating that they are not sensitive to the amount of biomass used and have good stability in microwave absorption performance. Moreover, the results of the simulation and modeling analyses of the radar cross section (RCS) further validate the efficacy of composite materials in attenuating microwaves. These results offer valuable insights into the stability of bandwidth in materials and the potential application of biomass in wave-absorbing materials. It also shows that the composites are highly promising and reliable candidates for microwave absorption applications due to their high-performance, wide-band, and thin-absorption properties.

Removal of Silicon from Magnesite by Flotation: Influence of Particle Size and Mechanical Mechanism.

The feasibility of producing high-density sintered magnesia with a one-step sintering method was investigated by utilizing finely ground magnesite as raw materials for direct flotation. The mechanism of flotation desilication of microfine grain magnesite was investigated by combining microstructure and chemical properties. The results showed that dodecylamine (DDA) has a sorting effect on magnesite reverse flotation desilication. Under the premise of 150 mg/L sodium polyacrylate (PAANa) as an inhibitor and 300 mg/L DDA as a collector, the content and recovery rate of MgO can reach 83.91% and 78.78%, respectively. When sodium oleate (NaOL) was used as a collector, the recovery rate of MgO was only 49.22%; therefore, it is unsuitable for magnesite purification. The flotation effect was affected because MgO particles and SiO2 particles agglomerated in the flotation process. The flotation agent cannot work for a single element but works for the mineral agglomerate. While collecting Si elements, the agglomerated MgO was also brought into the froth layer, making flotation impossible.

Preparation and thermal physical properties of MgO-(Nd1-xYx)2(Zr1-xCex)2O7 composite ceramics as a candidate for inert matrix fuel

In recent years, the MgO-Nd2Zr2O7 composite ceramics inert matrix (IM) was proposed as a candidate for the transmutation of Pu and minor actinides (MA) in light water reactors (LWR) or accelerator driven sub-critical system (ADS). To take full advantage of the pyrochlore structure of Nd2Zr2O7 to accommodate different types of MA and Pu, in this work, Y and Ce co-doped ωMgO-(1-ω)(Nd1-xYx)2(Zr1-xCex)2O7 (M-NYZC) composite ceramics used as a candidate IM for inert matrix fuel were prepared by solid-state one-step sintering method at 1500 °C for 3 h. The phase structure and microstructure of M-NYZC composite ceramics were characterized by XRD and SEM-EDS. Also, the thermal physical properties of M-NYZC composite ceramics including the thermal expansion coefficient and thermal conductivity were investigated systematically. Results from XRD and SEM-EDS showed that the magnesium oxide and NYZC pyrochlore solid solution are intermixed well with each other, and the M-NYZC samples present uniform element distribution with a grain size of about 1 μm. Also, the as-prepared samples possessed well densified microstructure, and the average relative density of all samples could exceed 95 %. Moreover, the thermal expansion coefficient and thermal conductivity of 0.5M-0.5NYZC (x = 0, 0.15, 0.2, 0.5, 0.9) samples were located in the range of 13.4 × 10-6–14.4 × 10-6 K-1 and 16.34–3.70 W·m-1·K-1 respectively. By comparison, the thermal physical properties of 0.5M-0.5NYZC samples are superior to that of traditional UO2 and MOX fuels. It is suggested that the M-NYZC composite ceramics prepared in this study can meet the thermal physical performances of inert matrix fuel.

Utilizing multi-solid waste to prepare and characterize foam glass ceramics

Incorporating multi-solid wastes to prepare foam glass ceramics could effectively improve the utilization rate of solid wastes, beneficial to promoting the crystallization and bloating of samples. In this study, foam glass ceramics were prepared by a one-step sintering method using waste glass (WG), granite tailings (GT), and high titanium blast furnace slag (HTBFS). At the same time, the phase transformation, sintering, and physical properties of the samples were studied. The results showed that the sintering of foam glass ceramics consisted of three stages: sintering densification, bloating, and bubble coalescence. The low-temperature melting of WG created a favorable liquid phase environment to precipitate microcrystalline phases, such as wollastonite, diopside, and titanite. Adding HTBFS helped crystallize the sample, but increased the viscosity of the system, not favorable for bloating. When the HTBFS content was <15%, the physical properties of the samples were as follows: a bloating temperature of 980–1100 °C, crystallinity of 0%–38.9%, porosity of 48.5%–60.2%, water absorption of 0.6%–1.2%, compressive strength of 9.3–22.6 MPa, and thermal conductivity of 0.31–0.43 W/(m·K). Consequently, the foam glass ceramics prepared in this study can be used in the field of structural insulation of buildings and has significant economic and social benefits.

Glass-ceramics synthesis using the collaborative smelting slag of spent automotive catalyst and copper-bearing electroplating sludge

This paper studied the glass-ceramics preparation from the collaborative smelting slag of spent automotive catalyst (SAC) and copper-bearing electroplating sludge (CBES) by the one-step sintering method without additional nucleating agents. The crystallization mechanism, including nucleation and crystal growth steps, was investigated by DSC, XRD and FETEM-EDS. The crystallization process during heat treatment could be summarized as follows: Fe3+ ions will congregate firstly in a small range on the surface and inside of the originally homogeneous amorphous matrix, and then gradually crystallize and transform into stable hematite (Fe2O3) crystal nuclei. Augite and gehlenite as the main two crystalline phases grow around hematite (Fe2O3) epitaxially. Additionally, the surface crystallization dominates the overall process based on the crystallization kinetics calculation. The optimum sintering temperatures of glass-ceramics preparation were researched according to the physicochemical properties analysis. When the sintering temperatures are 850℃−875℃, the density, water absorption, Vickers hardness, flexible strength, acid and alkali resistance of glass-ceramics products are 2.8–2.9 g/cm3, 0.08%–0.09%, 6.5–6.7 GPa, 98–115 MPa, 96.6%–96.9% and 98.5%–99.6%, respectively. Toxicity characteristic leaching procedure (TCLP) test shows that the material can be taken as non-hazardous. This work realizes resource utilization and detoxification of the co-smelting slag of SAC and CBES.

Versatile phosphor-in-glass based on Sn–F–P–O matrix with ultra-high color rendering for white LEDs/LDs

White light with excellent color rendering property has been highly required for comfortable and healthy illumination. A facile strategy to achieve high color rendering index (Ra >90) in practical applications is using near ultraviolet chips as excitation sources combined with RGB phosphors. However, achieving high color rendering with both blue chips and near-ultraviolet (NUV) chips for commercial phosphors dispersed in phosphor-in-glass (PiGs) materials is still a big challenge. In this work, the PiG based on the ultra-low melting point Sn–F–P–O glass with commercial green (Lu3Al5O12:Ce3+) and red (SrxCa1-xAlSiN3:Eu2+) phosphors has been successfully fabricated by one-step sintering method. The phase identification and distribution of monochromatic red phosphor in glass (R-PiG) and green phosphor in glass (G-PiG) were investigated in detail. The Sn2+ ions in Sn–F–P–O matrix show the intense blue emission bands centered at 420 nm under the excitation of NUV chips (365 nm). Notably, the polychromatic red/green phosphor in glasses (R/G-PiGs) are versatile and exhibited excellent color rendering (Ra = 93, Ra = 95, Ra = 92, respectively) properties excited by both blue chips, NUV chips and laser diodes (WLD). The working temperature of R/G-PiGs is stable at ∼33 °C and ∼55 °C when employed in WLEDs/WLDs (1 W), which greatly prevented the phenomenon of “thermal quenching” for the phosphors caused by high temperature. Thus, the versatile R/G-PiG with ultra-high color rendering and excellent thermal properties indicates its promising application in high-power white LEDs/LDs.

Reparation of porous Ti-Cu alloy by one-step sintering method and application of hydrogen evolution reaction

• The porous Ti-Cu alloy catalyst was synthesized by the one-step sintering method. • The introduction of Mo metal significantly improves the HER performance. • The first-principles approach gives the experiment a detailed interpretation of the atomic orbital hierarchy. In this paper, Ti-Cu porous alloy electrocatalysts were synthesized by simple mechanical alloying combined with a one-step sintering method, and the positive effects of milling time, sintering temperature, and sintering time on HER were explored. The results show that the Ti 2 Cu 3 porous alloy catalyst after ball milling has excellent electrocatalytic activity. After the introduction of transition metal Mo, the overpotential of ball-milled Mo-Ti 2 Cu 3 -600 electrocatalyst is 133 mV, and the corresponding Tafel slope is 97.37 mV·dec −1 , second only to commercial Pt/C catalyst. At the same time, the first principle was used to reveal the interaction of electrons in catalysis. The effective mass of the ternary alloy containing Mo is 0.19 m 0 , and the original alloy catalyst is 0.28 m 0 . It can be found that the introduction of Mo atoms improves the carrier migration efficiency, which has a high promotion effect on the catalytic performance of the original alloy. The reaction energy barrier is also reduced from 0.584 eV to 0.051 eV, which greatly improves the reaction process. Such a simple one-step sintering method can also obtain excellent electrocatalysts, which provides a new design idea for short-process processing of excellent electrocatalysts and has broad application prospects.

Improvement of electrochemical performance and structural stability of LiNi0.83Co0.12Mn0.05O2 at high-voltage by La and Ti modification

The large-scale commercialization of Ni-rich LiNi1−x-yCoxMnyO2 is hindered by the rapid capacity decay, which is caused by structural instability, interface side reaction, and surface phase transition. In this study, the Ni-rich cathode is modified with Ti and La through a one-step sintering method. Ti and part La diffuse into the cathode particles, and the rest of La is coated on the surface of the particles in the form of La4NiLiO8. The La and Ti modified cathodes show excellent cycling performance even at a high cut-off voltage of 4.5 V. The modified cathode has an initial capacity of 195.5 mAh g−1 and capacity retention of 87% after 200 cycles. The rate performance is also improved, and the capacity at 5 C reaches 178.3 mAh g−1. The improved cycling performance is attributed to the modification of La and Ti, which avoids structural degradation and maintains the mechanical integrity of the cathode particles during cycling. The improvement in rate performance is attributed to the fact that the Li+ diffusion coefficient is increased due to the modification.

Effects of solid isolation medium on the microstructure and magnetic properties of one-step sintered L10-FePtCu nanoparticles

To explore a more efficient process parameter for controlling the microstructure and magnetic properties of liquid-phase assisted one-step sintering method, the effects of isolation medium size and uniformity on L10-FePtCu NPs have been studied. The grain size (d) of L10-FePtCu NPs has been refined by decreasing the average size of solid isolation mediums (D), and the relationship can be approximated as d= 6.60 × D1/3 − 9.14. The disorder-order transition of the L10 phase has been inhibited by decreasing the medium size, however, it has been facilitated by increasing the medium size uniformity. The ordering degree, coercive force, and magnetic energy product of L10-FePtCu NPs reach the highest when using the middle sized and best uniformity NaCl mediums (about 8 µm). This research indicates that controlling the interface between the solid isolation mediums and the precursors is an effective strategy to tune the microstructure and magnetic properties of one-step sintered highly ordered L10 phase NPs.

Preparation of MgO-Nd2Zr2O7 composite ceramics used for inert matrix fuel by one-step sintering method

MgO-Nd2Zr2O7 composite ceramic is a promising candidate as an inert matrix material for the transmutation of Pu and minor actinide. In this work, the MgO-Nd2Zr2O7 composite ceramics (hereafter M-NZO) with 30–70 wt% mass percent of MgO were successfully prepared at 1500 °C for 24 h via direct solid-state reaction one-step method. This method achieved the integration of Nd2Zr2O7 pyrochlore synthesis and M-NZO composites sintering, which shows a significant improvement in the simplification of the preparation process than the traditional two-step method. The structural properties and compactness of the as-prepared composite ceramics were systematically investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM). It was confirmed that the as-prepared M-NZO ceramics are composed of only crystalline MgO and Nd2Zr2O7 phases, and the mass fractions of two phase are almost the same as the designed nominal chemical composition. The composite ceramics showed remarkable densification and the relative density is higher than 98.2%.

Low-cost preparation and characterization of MgAl2O4 ceramics

Low-cost magnesium aluminate spinel ceramics were successfully synthesized from the minerals of magnesite(M) and bauxite(B) via the one-step sintering method. The effect of the ratio of bauxite to magnesite on the phase evolution, microstructure, as well as the mechanical properties was thoroughly investigated. The phase structural analysis indicated that Mg2+ or Al3+ ions were dissolved in the spinel lattice and formed Mg-rich/Al-rich spinel MgAl2O4 (MA). The microstructure analysis revealed that the liquid phase gradually appeared with the increment of bauxite content. Appropriate but not saturated cation solution had the effects of structural densification, homogenization of crystal grains, and the enhancement of strength. Ceramics with 1.31 bauxite to magnesite stoichimetric ratio exhibited the highest density of 3.43 g/cm3 and flexural strength of 93.5 MPa.