Sintering Time Research Articles

Structural and mechanical optimization of porous alumina structures fabricated by carbon sacrificial template

The Taguchi method is used to optimize the manufacture of porous alumina made through reactive spark plasma sintering and carbon sacrificial template. The goal is to design a new versatile procedure that allows the fabrication of porous alumina with tailored physical properties. The structural and mechanical properties taken as target parameters were the subtle combination of porosity and Young’s modulus of the human cortical bone: typical pore size ¿100μm, and Young’s modulus in the range of 3–30 GPa. The input factors of the Taguchi method are wt.% of carbon, sintering time, calcination heating rate, and final heat treatment. Hg porosimetry, electron microscopy, uniaxial compression and computer aided tomography were used for the characterization of the porosity, pore size distribution, pore interconnectivity, and Young’s modulus. Finally, according to the conclusions of the Taguchi analysis, the parameters of the process were changed for the fabrication of the new samples with optimized properties. Highly porous structures with 90% interconnectivity, Young modulus of 5.5 ± 1.1 GPa, and compression strength of 49 ± 20 MPa, were obtained, successfully emulating the targeted properties.

The role of the LATP particle size as a cornerstone of the cold sintering process

An innovative sintering technique, the Cold Sintering Process (CSP), has been employed to obtain dense Li1.3Al0.3Ti1.7(PO4)3 (LATP) Solid-State Electrolytes (SSE) by optimising the particle size (d50) of the starting powder. The CSP is carried out at 700 MPa, 150 ºC, and 90 min of sintering time, using acetic acid solution as Transient Liquid Phase (TLP). The CSP lowers the LATP sintering temperatures almost 1000 ºC. To study the electrical properties, an in operando Electrochemical Impedance Spectroscopy (EIS) technique has been used. The optimum d50 is 0.415 µm, yielding to competitive microstructure and electrical properties (ionic conductivity of 6.93·10−5 S cm−1 at 30 ºC, activation energy of 0.363 eV, and a relative density of 81.2 ± 0.8%). Relative density, ionic conductivity and TLP content must be balanced, because at small d50, although relative density is enhanced the ionic conductivity is reduced. A packing model has been used to understand this behaviour and the mass transfer mechanisms.

Effect of Sintering Time and Cl Doping Concentrations on Structural, Optical, and Luminescence Properties of ZnO Nanoparticles

Zinc oxide (ZnO) nanoparticles were synthesized hydrothermally using zinc acetate dihydrate and sodium thiosulfate pentahydrate precursors. The synthesized powders were sintered in air at 600 °C for different durations with a Cl-doping concentration of 25 mg/g. The optimal sintering time was found to be 5 h, resulting in the successful formation of the ZnO phase with small particle sizes of around 90 nm, nominal atomic fractions of Zn and O (~50%, ~50%), and increased luminescence intensity. The ideal concentration of Cl was discovered to be 25 mg/g of ZnO, which resulted in the highest luminescence intensity. The ZnO luminescence characteristics were observed in emission bands peaking at approximately 503 nm attributed to the transition from oxygen vacancies. A considerable improvement in the emission intensity was observed with increased Cl doping concentration, up to eight orders of magnitude, compared to pristine ZnO nanoparticles. However, the luminescence intensity decreased in samples with higher concentrations of Cl doping due to concentration quenching. These preliminary outcomes suggest that Cl-doped ZnO nanoparticles could be used for radiation detector development for radon monitoring and other related applications.

Thermoluminescent composites of sintered synthetic-topaz/in situ corundum for dosimetry by a novel reversible process

Topaz (Al2F1·44(OH)0·56SiO4)/corundum (Al2O3) composites were prepared by a facile and novel reversible process from the sintering of synthetic topaz and AlF3 powders, with corundum formed in situ into the topaz matrix. The corundum formation reaction occurs in the temperature range 875–975 °C, from 40 min sintering time, obtaining the topaz- Al2F1·44(OH)0·56SiO4/corundum- Al2O3 composites. Although sintering temperature and time increment lead to higher corundum formation in the topaz matrix (78.4 wt % Al2O3 at 975 °C for 60 min), longer residence times give place to corundum percentage decrease due to topaz reconversion. The composites' microstructure is characterized by a rectangular bar with stacked pyramidal ends and polycrystals of hexagonal plates for topaz and corundum, respectively. For the topaz/corundum composites, the maximum density was 3.05 g/cm3 (17 % porosity) for specimens sintered at 925 °C for 20 min. The glow curves of the topaz/in situ corundum composite sintered at 975 °C and 0 min dwell time show thermoluminescent peaks between 180 and 250 °C, useful for dosimetric applications. The most helpful peak (at 221 °C) in the topaz/corundum composite's glow curves determined by computational deconvolution is sharp and exhibits the highest thermoluminescent response. Dose-response analysis of the composite (sintered at 975 °C for 0 min) with the best thermoluminescent response revealed two ranges of linear behavior, the first from 2 to 200 mGy, with an adjustment of 99.9 % and the second in the range 5–300 Gy (99.8 % fitting). The thermoluminescent response improvement of the topaz/corundum composites is attributed to the corundum formed in situ during sintering. Fading rate studies of the composite with the best sintering treatment revealed a signal decrease of 4 % after 15 days, which remained constant for up to 30 days, and 8 % after 60 days. The kinetic parameters, kinetics order (b), activation energy (E), and frequency factor (s) determined using the glow peak shape method showed second-order kinetics. The topaz/corundum composite with the best TL response (975 °C, 0 min) presents an effective atomic number (Zeff) of 11.74. The detection of lower doses (mGy) and the linear response at higher doses (Gy) of beta 90Sr, together with the other thermoluminescent properties, suggest that the topaz/corundum composites sintered at 975° for 0 min dwell time may find application in radiotherapy, geological dating, and environmental dosimetry.

Effect of Addition of ZrO2 on Biaxial Flexural Strength of Calcium Phosphate Ceramics

The aim of this study is to investigate the effect of addition of ZrO2 on the biaxial flexural strength (BFS) of ceramics fabricated using a conventional powder technology. Various compositions of hydroxyapatite (HAp) Ca10(PO4)6(OH)2 and zirconia powder ZrO2, ranging from 10 to 90 wt% ZrO2, were prepared using a wet mixing process. Ten compacts (13.5mm3mm) were made for each group, pressed and sintered in air at sintering temperatures from 1100 to 1450oC for up to 12 hours. The bulk density, porosity, linear shrinkage and BFS. The porosity reduced and linear shrinkage increased with increasing sintering temperature and amounts of zirconia, whereas the sintering time had little effect. The highest mean value achieved for the BFS was 26920 MPa for a composition of 70% ZrO2 and 30% HAp fired at 1450oCfor 6 hours. From the experimental results can be conclude that sintering temperature and composition affect densification behaviour of calcium phosphate/ ZrO2 composites. The BFS increases with a reduction of porosity and increases with both sintering temperature and additions of ZrO2. It was noted that there is considerable scope for improvement in the BFS values by reducing the porosity of these composites.

A novel approach to improve reliability of aerosol jet printing process

Additive manufacturing is gaining interest for printing of noble metals. In this study, aerosol jet printing was applied to fabricate traces from commercial silver nanoparticle ink. A self-built three dimensional printing machine was used without or with in-line substrate heating. Subsequently, sintering was conducted by furnace or near-infrared source. Examination of the sample using scanning electron and atomic force microscopy revealed the existence of both micro- and nanoscale pores in the structure. Local open porosity, aerosol extensive spatter and wide porous overspray were key defects found in samples printed without substrate heating. All the features affect the properties and reliability of silver prints. In-line process heating increased the concentration of nanoparticles and limited defects formation. The final structure was influenced by sintering method and its time. Elongated time of sintering decreased porosity and roughness of the printed traces. Nevertheless, IR sintering provided the smoothest sample surface, and significantly improved bonding of aggregates.

Optimizing the sintering process parameters for simultaneous improvement of the compression strength, impact strength, hardness and corrosion resistance of W–Cu nanocomposite

The main purpose of this work is to optimize the mechanical properties of tungsten–copper (W–Cu) nanocomposite fabricated by the sintering process. For this purpose, the parameters of sintering temperature, sintering time and weight percentage of copper were selected to optimize the compression strength, impact strength, hardness and corrosion resistance of the W–Cu nanocomposite using the desirability function procedure and response surface method. The analyses of transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were also performed to examine the microstructure of W–Cu nanocomposite. The results exhibited that a rise in the sintering temperature from 1000∘C to 1150∘C significantly enhanced the impact strength of W–Cu nanocomposite, while a rise in the sintering temperature from 1150∘C to 1300∘C deteriorated the impact strength. Moreover, the compression strength and hardness of the W–Cu nanocomposite continuously improved by elevation of sintering temperature from 1000∘C to 1300∘C. A rise in the amount of Cu from 20[Formula: see text]wt.% to 40[Formula: see text]wt.% led to a reduction in the hardness of the W–Cu nanocomposite, while a rise of Cu content improved the impact and compression strengths. The results also indicated that the mechanical properties of W–Cu nanocomposite enhanced simultaneously by using 27[Formula: see text]wt.% Cu at sintering temperature of 1197∘C and sintering time of 2.7[Formula: see text]h. The samples sintered at the optimal conditions indicated a higher corrosion resistance than that sintered at the initial conditions.

Influence of sintering condition on tribological properties of (Hf-Ta-Zr-Nb-Ti)C carbides

The wear behavior of high-entropy (Hf-Ta-Zr-Nb-Ti)C ceramics (HECs) was investigated using the ball-on-flat linear reciprocating method/dry sliding in the air. The experimental materials were prepared by ball milling and spark plasma sintering at 2100 °C and 5, 10, or 20 min sintering time. The HECs achieved relative density from 99.5% to 99.9%, with homogeneous chemical composition and grain sizes of HEC from 8 μm to 11 μm. The sintering times showed no significant influence on the wear characteristics of the investigated specimens. However, very promising mechanical and tribological properties of HEC were obtained. The materials had Young's modulus from 452 GPa to 482 GPa, Vickers' hardness from 20.9 GPa to 22.0 GPa, and Indentation fracture resistance of ∼2.8 MPa·m1/2 - 2.9 MPa·m1/2. The measured values of specific wear rate varied from 1.18 × 10−6 mm3/N·m to 3.23 × 10−6 mm3/N·m and coefficient of friction under different loads were very similar, between 0.29 and 0.32. The dominant wear mechanisms in all cases were mild abrasion with limited oxidation-driven tribochemical reaction.

SPECIFIC FEATURES OF THE CURRENT FLOW THROUGH AN ALUMINA-BASED METAL-CERAMIC COMPOSITE DURING ELECTRON BEAM IRRADIATION IN THE FOREVACUUM PRESSURE RANGE

We describe some specific features of the current passage through an Al<sub>2</sub>O<sub>3</sub>-Ti metal-ceramic composite sample during irradiation by a forevacuum-pressure plasma-cathode electron beam source. The composition ratio of the composite was 90% Al<sub>2</sub>O<sub>3</sub> and 10% Ti by weight. It is shown that during electron-beam irradiation, the magnitude and direction of the current through the sample depend on the temperature as well as on the sintering time at given temperature. The absolute value of the recorded current can reach 15 mA for an electron-beam current of 60 mA and electron energy of 10 keV. The dependence of the current is caused by redistribution of titanium over the depth of the sintered composite during heating, and provides a means for forming gradient metal-ceramic materials with variable content of components over the depth.

Composite solid electrolytes based on Li7La3Zr2O12 for all-solid-state lithium power sources

Currently development of all-solid-state lithium batteries are in great demand all over the world. Li7La3Zr2O12 (LLZ) compounds are considered as perspective solid electrolyte for such power sources. However, these solid electrolytes of garnet family have some disadvantages – high temperatures of ceramic synthesis, poor wettability by Li and low stability to air components. The creation of composite solid electrolytes based on LLZ is one of the ways to solve these problems. It was established that the temperature and/or sintering time of the solid electrolyte could be reduced by the introduction of different additives with maintaining lithium-ion conductivity values (10–5–10–4 S/cm at room temperature). It should be noted that the used sintering additive should meet the following requirements: low softening temperatures, high values of lithium-ion conductivity, stability in contact with lithium metal and absence of chemical interaction between components leading to the formation of low-conductivity impurity phases. Thus, the development of composite solid electrolytes based on LLZ is perspective for all-solid-state power sources.

Effects of La doping on diffused ferroelectric phase transition, electric and dielectric properties of lead-free SrBi2Ta2O9 ceramics

Citric acid-assisted method was used to synthesize pure polycrystalline La-doped SrBi2Ta2O9 powders which were uniaxially pressed and sintered under different conditions. La doping of SrBi2Ta2O9 resulted in the shortening of Ta-O bond lengths, but increased the unit cell volume and decreased the crystallite size. The effect of sintering process on dielectric properties was studied in order to find optimal sintering conditions. Dielectric loss, measured at room temperature, increases when sintering temperature rises from 1100 to 1200?C, as well as when sintering time increases from 6 to 9 h. Thus, further investigation was performed on the sample sintered at 1100?C for 6 h. The obvious change in ?? around TC and diffusive phase transition, pronounced for the ceramics with higher La content, were characteristic of the doped ceramics. The diffused ferroelectric phase transition behaviour is caused by structural disorder at the Sr-sites (Sr, Bi and La cations) in the Bi2O2 layers and perovskite blocks. The electrical conductivity increases steadily at lower temperatures (below 200 ?C), but shows a strong temperature- and frequency-dependent trend at higher frequencies. La-doping decreases conductivity by hindering charge carriers? long-distance mobility.

Hydroflux-assisted cold sintering: eutectic mixtures for boosting ionic conductivity in LATP solid-state electrolytes

Superior electrical properties have been achieved for a Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid-state electrolyte (SSE) by using the novel hydroflux-assisted cold sintering process (HACSP) at 400 MPa, 200 °C and 90 minutes of sintering time.

Production of Recycling Prototype of Machining Teflon Waste by Compression Molding and Sintering and Investigation of Mechanical Properties

In this study, for the first time within the Arnes Mechanical Machinery Design Center, the recycling of Teflon (PTFE-Polytetrafluorethylene) wastes generated in the production of sealing elements by machining process was carried out, and know-how was obtained for the use of this recycling prototype as a secondary raw material. Within the scope of the study, the recycling prototype, which was separated as waste after the machining process, was characterized by DSC analysis and ground to 250-micron sizes. The resulting Teflon prototype was pressed by pressure molding and sintering processes. 370-390°C temperature and 2-4 hours time parameters were selected for sintering. To determine the mechanical properties of the secondary raw material prepared as a recycling prototype, a tensile test mold was designed, and tensile test samples were produced. As a result of the study, it was seen that the recycling Teflon prototype was successfully produced. It was determined that the mechanical properties of the produced prototype improved with increasing sintering temperature and time. Environmental sustainability will be ensured by reusing the second-quality raw materials from the study in production.

Rapid processes for the production of nanocrystal yttria-stabilized tetragonal zirconia polycrystalline ceramics: ultrasonic spray pyrolysis synthesis and high-frequency induction sintering

In this study, nanocrystalline 3 mol % yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic was produced by sintering with a high-frequency induction heating (HFIH) system of granular powders obtained by ultrasonic spray pyrolysis (USP) at 600 °C. The granular nano-sized powders (10-30 nm) were micron in size (average size: 700 nm), spherical in shape and amorphous. The influences of the HFIH sintering temperature (1400-1600 °C), applied current time (60-300 sec.) and the mechanical pressure (10 MPa and 20 MPa) on the final density and grain size of the products were investigated. The amorphous granular Y-TZP powders compressed with the HFIH system allow very rapid condensation in the tetragonal phase at high density and avoid grain growth. High density (relative density over 95) nanocrystalline Y-TZP ceramic with ∼70 nm size could be obtained from the simultaneous application of 20 MPa pressure and an induced current within 300 sec. of sintering time at 1500 °C. In this condition, the sample’s maximum hardness and fracture toughness values were reached at 14.9 GPa and 3.8 MPa·m1/2, respectively. Y-TZP powders produced in nano-micro structure with the USP system were sintered with the HFIH system and rapid production was achieved by preventing grain growth.

Fabrication and film-forming mechanism of PCTFE films with exceptional water-vapor barrier and mechanical properties via solvent-assisted method

Polychlorotrifluoroethylene (PCTFE) has the outstanding water-vapor barrier performances among thermoplastics, and is with excellent transparency, high cryogenic toughness, and ultralow dielectric constant/loss. It plays an important role in high-performance packaging, electric circuit constructions, anti-corrosion coatings, cryogenic sealing, and so forth. Nevertheless, due to its borderline thermal stability and sensitivity to shearing effect, the melt-processing of PCTFE is rather difficult. Herein, a solvent-assisted method, which contained fabrication, coating, drying, and sintering of PCTFE suspension, was proposed for the fabrication of PCTFE films. The influence of processing parameters, including particle shape, drying temperature, and sintering time on the film-forming process was investigated. The as-prepared PCTFE films exhibited exceptional mechanical properties, with a tensile strength and failure strain of ∼42 MPa and ∼108 %, respectively. The water vapor transmission rate, light transmittance, and haze reached ∼0.02 g/(m2·24 h), ∼91 %, and ∼3 %, respectively. Finally, the potential film-forming mechanism was explained by the densification of PCTFE particles via capillary force, neck formation and particles coalescence driven by surface tension and viscous flow, and co-crystallization across the initial particle interfaces. In summary, the solvent-assisted method opened a new pathway for the processing of PCTFE films and is conducive to broadening their application fields.

Dental zirconia microwave-sintering followed by rapid cooling protocol

ObjectivesThis study aimed to evaluate the effect of microwave sintering temperature and cooling rate (MS) on 3Y-TZP ceramics and its influence on the ceramic microstructure and mechanical properties. Specifically, to optimize the sintering process, reducing the total sintering time compared to conventional sintering. Materials and methodsEighty-four pre-sintered Y-TZP discs (Vipi block Zirconn, VIPI) (ISO 6872) were divided into seven groups (n = 12) according to the sintering conditions: conventional sintering (CS) at 1530 °C for 120 min and microwave sintering at 1400 °C (MS1400) and 1450 °C (MS1450) for 15 min followed by different cooling conditions: rapid cooling (RC), cooling at 400 °C (C400) and 25 °C (C25). The specimens were submitted to apparent density measurements, X-ray diffraction analysis (XRD), scanning electron microscopy, and biaxial flexural strength test. Data was statistically analyzed through two-way ANOVA, Tukey, Sidak, Dunnett and Weibull (α = 0.05). ResultsAll MS1400 groups presented lower density values than the CS and MS1450 groups. Two-way ANOVA revealed that the MS temperature and cooling rate affected the biaxial flexural strength of the Y-TZP (p < 0.01). Group MS1400RC presented lower biaxial flexural strength values (681.9 MPa) than MS1450RC (824.7 MPa). The cooling rate did not statistically decrease the biaxial strength among the groups submitted to microwave sintering at 1450 °C. XRD analysis showed that the sintering and cooling temperature did not induce tetragonal to monoclinic phase transformation. ConclusionsMicrowave sintering at 1450 °C for 15 min followed by rapid cooling can be a viable fast alternative protocol for Y-TZP sintering, compared with the conventional sintering, reducing the total sintering time by 75% and reducing the energy used for the sintering process without affecting the Y-TZP biaxial flexural strength and relative density compared to the conventional sintering. Moreover, the microwave technique promoted smaller grains and did not induce monoclinic phase formation.

Intolerance of Ruddlesden-Popper La2NiO4±δ Structure to a-Site Cation Deficiency

Mixed ionic-electronic conductors derived from Ruddlesden-Popper Ln2NiO4+δ (Ln = La, Pr, Nd) attract significant attention as oxygen electrode materials for solid oxide fuel and electrolysis cells. However, literature data on the impact of A-site deficiency on the phase relationships and functional properties of Ln2NiO4+δ-based phases are contradictory. While some works report an accommodation of A-site vacancies up to x = 0.15 in La2-x NiO4±δ, others indicate difficulties in the synthesis of single-phase La2-x NiO4+δ even for low x values. The present work explores the impact of the nominal A-site deficiency on the phase composition and electrical transport properties of La2-x NiO4±δ ceramics.Ceramics with the nominal composition La2-x NiO4±δ (x = 0, 0.02, 0.05, 0.10) were synthesized by the glycine-nitrate technique and sintered at 1350-1450°C. While XRD analysis suggested the formation of single-phase materials with orthorhombic K2NiF4-type structure, the lattice parameters remained independent of composition within the experimental uncertainty. Neutron diffraction studies of x = 0 and 0.05 samples revealed that the lattice parameters, La:Ni atomic ratio (2:1) and oxygen sites occupancy remain identical for both samples, while the presence of impurity NiO phase (0.4 wt.%) was detected for La1.95NiO4±δ. SEM/EDS inspection of ceramic samples confirmed the presence of nickel-rich inclusions for x ≥ 0.02, which could not be eliminated by increasing the temperature and time of sintering. The volume fraction of inclusions increased with x. The experimental observations are supported by the atomistic simulations showing that the coexistence of cation-stoichiometric La2NiO4+δ with nickel-rich La4Ni3O10 or NiO is more favorable compared to cation-deficient La1.95NiO4±δ. Molecular dynamics simulations of La1.95NiO4±δ lattice demonstrated that the introduction of La vacancies leads formation of instability zone in the rock-salt-type layer and destabilization of the crystal lattice. The intolerance of La2NiO4+δ lattice to A-site vacancies and coexistence of La2NiO4+δ with traces of Ni-rich secondary phase in the samples with the nominal composition La2-x NiO4±δ results in an insignificant variation of electrical transport properties with x. Acknowledgements This work was developed within the scope of the project CARBOSTEAM (POCI-01-0145-FEDER-032295) funded by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) and by national funds through FCT/MCTES, and the project CICECO-Aveiro Institute of Materials (UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020) financed by national funds through the FCT/MCTES (PIDDAC). A.B. acknowledges the PhD scholarship by the FCT (grant SFRH/BD/150704/2020). This work was partially supported by the National Science Centre, Poland, grant UMO-2020/37/B/ST8/02097.

Improvement of Ionic Conductivity in Li7La3Zr2O12 (LLZO) Solid Electrolyte By Doping with Aluminum/Tungsten

Recently, there has been increasing interest in solid electrolytes, which are the most important materials in all-solid-state lithium-ion batteries. Among all solid electrolytes, garnet-type Li7La3Zr2O12 (LLZO) has been proven to be one of the most promising electrolytes due to its high Li+ conductivity, wide potential window, and electrochemical stability towards metallic lithium anode. In particular, cubic garnet-type LLZO solid electrolytes have received a lot of attention for the development of high-performance all-solid-state batteries with safety, energy density, and long cycle life. In this study, we synthesized LLZO solid electrolyte powders with garnet structure and determined the optimal composition and sintering temperature by adding Al/W to form a stable cubic phase.In this study, Al or W-doped LLZO were prepared by a post-doping method. In this process, LLZO powder was first prepared, and then mixed with Al2O3 or WO3 powders to produce doped LLZO ceramic electrolytes, respectively. During this process, the doped ions entered the LLZO lattice, increasing the lithium ion transport channels and promoting lithium ion conductivity. The sintering time, crucible, and sintering temperature were adjusted to investigate the optimal process conditions of the post-doping method. As a result, the doped solid electrolyte exhibited high lithium ion conductivity and low activation energy. Using the high lithium ion conductivity and broad electrochemical stability window of the Al or W doped LLZO SSE, the (NCM622)/(Al or W doped-LLZO) cell delivered a steady cycle for 100 cycles at 0.1C. The Al or W doped-LLZO prepared in this study showed advantages of high conductivity, simple preparation process, high reproducibility, and low cost, which provides technical support and reference for further application of garnet-type SSEs in solid-state batteries with high energy density.

The Effect of Sintering on Zirconia Manufactured via Suspension-Enclosing Projection Stereolithography for Dental Applications: An In Vitro Study.

Zirconia is a widely used material in the dental industry due to its excellent mechanical and aesthetic properties. Recently, a new 3D printing process called suspension-enclosing projection stereolithography (SEPS) was introduced to fabricate zirconia dental restorations. However, the effect of the sintering time and temperature on the properties of zirconia produced via SEPS has not been fully investigated. Zirconia slurries were prepared with varying percentages of zirconia powders and 3D printing resins, and 5Y-TZP (5 mol% yttria-stabilized zirconia) (n = 40) and 3Y-TZP (3 mol% yttria-stabilized zirconia) (n = 40) bar specimens were fabricated via SEPS manufacturing. The specimens were sintered at different temperatures and dwell times, and their flexural strength, density, and phase composition were measured. The viscosity of the slurries was also measured. Statistical analysis was performed using Welch's ANOVA and Kruskal-Wallis tests to evaluate the impact of the sintering conditions. Significant differences in flexural strength (p < 0.01) were observed between the 5Y-TZP samples, with those sintered at 1530 °C for 120 min showing an average strength of 268.34 ± 44.66 MPa, compared to 174.16 ± 42.29 MPa for those sintered at 1450 °C for 120 min. In terms of density, significant differences (p < 0.01) were noted for the 3Y-TZP specimens, with an average density of 6.66 ± 0.49 g/cm3 for samples sintered at 1530 °C for 120 min, versus 5.75 ± 0.55 g/cm3 for those sintered at 1530 °C for 10 min. X-ray diffraction confirmed the presence of a predominantly tetragonal phase in both materials. Zirconia printed via SEPS manufacturing can be sintered at a higher temperature with shorter dwell times, thereby producing high density samples. Different sintering conditions can be used to fully sinter 3D-printed zirconia for potential dental applications.

Synthesis and Characterization of the New Li1+xAl1+xSi1-xO4 (x = 0-0.25) Solid Electrolyte for Lithium-Ion Batteries.

A systematic study was performed to investigate the effect of the sintering temperature, sintering duration, and aluminum doping on the crystalline structure and ionic conductivity of the Li1+xAl1+xSi1-xO4 (LASO; x = 0-0.25) solid electrolyte. There was a strong indication that an increase in the sintering temperature and sintering time increased the ionic conductivity of the electrolyte. In particular, the doping concentration and composition ratio (Li1+xAl1+xSi1-xO4; x = 0-0.25) were found to be crucial factors for achieving high ionic conductivity. The sintering time of 18 h and lithium concentration influenced the lattice parameters of the LASO electrolyte, resulting in a significant improvement in ionic conductivity from 2.11 × 10-6 (for pristine LASO) to 1.07 × 10-5 S cm-1. An increase in the lithium concentration affected the stoichiometry, and it facilitated a smoother Li-ion transfer process since lithium served as an ion-conducting bridge between LASO grains.