Uniform Particle Size Distribution Research Articles

Development, Characterization, and Investigation of In Vivo Targeted Delivery Efficacy of Luteolin-Loaded, Eudragit S100-Coated mPEG-PLGA Nanoparticles.

Luteolin (Lu) is a kind of flavonoid that has been proved to treat non-alcoholic fatty liver disease by alleviating intestinal microbiota disorder. In this study, luteolin was coated with methoxy poly(ethylene glycol)-poly(dl-lactide-co-glycolic acid) (mPEG-PLGA) using an emulsion solvent evaporation method, and the optimum preparation process was determined by a single-factor experiment combined with response surface methodology (RSM). Methacrylic acid-methyl methacrylate (1:2) copolymer (Eudragit S100) was then used to coat the surface of Lu/mPEG-PLGA nanoparticles. The physical parameters of Eudragit S100-coated Lu/mPEG-PLGA nanoparticles (Lu-NPs), such as appearance, particle size, potential, particle size distribution and drug release, and stability in vitro, were evaluated. In addition, its cytotoxicity in vitro, pharmacokinetics, tissue distribution, and toxicity in vivo were also studied. The results showed that the prepared Lu-NPs had uniform particle size distribution, high encapsulation efficiency, and good stability. Normal colonic epithelial cells showed good tolerance to Lu-NPs. After oral administration, the blood concentration of luteolin peaked at 8h, and the main tissue distribution was within the colon, confirming its colon-targeted profile. Safety assessments also indicated that no significant changes were observed in main organs after administration of Lu-NPs. The use of Eudragit S100-coated Lu/mPEG-PLGA nanoparticles is a new strategy for colon-targeted delivery of luteolin that encourages luteolin to fulfill its role in the colon.

Study on the Grinding Kinetics and Magnetic Separation of Low-Grade Vanadiferous Titanomagnetite Concentrate

In recent years, a low-grade vanadiferous titanomagnetite concentrate (LVTC) produced in the northwest area of Liaoning has attracted more and more attention. However, it is difficult to recover and utilize valuable minerals such as iron, titanium, and vanadium, due to their special physical and chemical properties and complex mineral composition. Grinding and magnetic separation are two important operational units for recovering valuable metal components from vanadiferous titanomagnetite. Therefore, the grinding kinetics of the LVTC in northwestern Liaoning were first studied by means of grinding kinetics equations in this paper. The results show that the grinding process of LVTC is consistent with the grinding kinetics equation, and the sieve residues of particles approached a constant value after grinding for 30 min, resulting from equilibrium between the fragmentation and agglomeration processes. In addition, equivalent particle size (EPS) and specific surface area (SSA) were linearly proportional to the double logarithm of grinding time, and the correlation coefficients for fitted data by the Rosin–Rammler–Bennet (RRB) model were slightly higher than those by the Swebrec model, and could reflect the dispersibility and uniformity of particle size distribution (PSD) quantitatively. Then, the grinding products were separated by magnetic separation, and the influence of grinding conditions on the grade and recovery ratio of Fe and TiO2 in the LVTC was analyzed. As a result, grinding time has a significant impact on the recovery ratio and grade of Fe and TiO2 during the magnetic separation process, and the LVTC grinding duration is not as prolonged as it might be, as the optimal grinding time is 20 min. Titanomagnetite, ilmenite, and titanite are still the predominant phases in all magnetic separation products at optimal grinding time, but the intensity or content of these three minerals varies between magnetic separation products, and 232 kA/m magnetic field intensity has a higher separation efficiency than 134 kA/m magnetic field intensity.

Effects of heat treatment on physicochemical and microstructure properties of myofibrillar proteins combined with glucose and cellulose nanofibers

The effects of unheated, 80 °C, 100 °C, and 121 °C on the physicochemical and microstructural properties of myofibrillary protein (MP) supplemented with glucose (Glc) and cellulose nanofibers (CNFs) were studied. The results showed that Glc and CNFs cross-linked with MP through non-covalent bonds when unheated compared with the unheated MP group, which increased the particle size and surface hydrophobicity of MP, and changed the secondary structure. At 80 °C and 100 °C, the particle size and hydrophobicity of MP significantly increased. At 121 °C, the contents of leucine and lysine in MP decreased by 16.2% and 19.9%, respectively, however, both Glc and CNFs could prevent this decrease. Meanwhile, microscopic images showed that the dispersion of Glc-MP and CNFs-MP were more uniform than the MP groups. Compared with Glc-MP, CNFs-MP had more uniform particle size distribution and better thermal stability at high temperatures (121 °C).

Effect of enzymatic hydrolysis conditions on structure of soy protein isolate/gum arabic complex and stability of oil-in-water emulsion.

The emulsifying, antioxidant and foaming properties of soy protein isolate hydrolysates (SPH) can be improved by the addition of gum arabic (GA). We investigated the effects of different hydrolysis conditions on the complexation of SPH and GA, and the effects of the complex on the properties of emulsions. Fluorescence spectroscopy showed that the addition of GA had a stronger effect on bromelain and pepsin hydrolysates than trypsin hydrolysate, and therefore had a higher binding constant (KA ) and a larger number of binding sites (n). The addition of GA could also improve protein solubility and emulsifying ability. The emulsions prepared with complexes, especially the complex of GA and SPH obtained by pepsin hydrolysis for 3h, had a high absolute charge value, uniform particle size distribution, stable morphology, and good storage stability. After storage, the emulsification index (CI) of the emulsion only increased to 23.08%; its 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity was 24.37 ± 1.22% and its 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS+ ) free radical scavenging activity was largely retained. During long-term storage, pepsin-treated protein (especially protein treated for 3h) and GA can form a stable emulsion with antioxidant properties. This work provides new ideas for the development of natural and safe emulsifiers that have antioxidant properties and can be stored long-term and used in the food industry. © 2022 Society of Chemical Industry.

Regeneration of high-performance Li1.2Mn0.54Ni0.13Co0.13O2 cathode material from mixed spent lithium-ion batteries through selective ammonia leaching

The efficient recycling process of spent lithium-ion batteries (LIBs) to regenerate electrode materials can alleviate the metal resources scarcity and environmental pollution. Here, the Li-rich cathode Li1.2Mn0.54Ni0.13Co0.13O2 (LR) material was successfully re-synthesized via an environment-friendly and impurity-free recycling process combined ammonia leaching with sol-gel process. Compared with the general methods, ammonia leaching is delicately applied to selectively extract valuable metals from spent LiNixCoyMnzO2 materials exclusive of other impurities (Fe, Al). The process facilitates the subsequent recovery without additional purification process. Surprisingly, the leaching efficiency of Li, Ni, and Co elements is up to as high as 99.28%, 99.63%, and 99.76%, respectively. After adding extra metal compounds stoichiometrically, LR with uniform particle size and elements distribution was regenerated from the valuable metals in the lixivium via the sol-gel method. The LR synthesized at 800 °C exhibits a satisfying capacity of 246.5 mAh g−1 at 0.1 C and high-stable cycle performance with a capacity of 163.3 mAh g−1 after 80 cycles at 0.2 C between 2.0 and 4.8 V. The fundamental results provide inspiration for recovery of the complex spent LIBs, which can selectively separate the multiple metal impurities with high-efficient reutilization.

Hydrogen arc plasma promotes the purification and nanoparticle preparation of tungsten

As an important refractory metal, tungsten (W) has unique physical-chemical properties, and the applications of high-quality tungsten NPs with uniform particle size, high purity, and good particle dispersion in industrial fields are highly desirable. Herein, the integration of tungsten metallurgical purification and nanoparticle preparation is achieved by the hydrogen arc plasma method. In the process of purification, on the condition of arc current of 250 A, hydrogen concentrations of 30 vol%, purification time of 40 min, and gas pressure of 60 kPa, the highest impurity removal rate is achieved. The active H+ is able to react with impurities to generate metal hydride (MH, M = Al, Cr, Mg, and Fe), which promotes the removal rate of impurity elements. During the preparation of nanoparticles (NPs), the as-prepared tungsten NPs with an average particle size of 44.1 nm have a regular spherical structure, high purity, and a relatively uniform particle size distribution. When the hydrogen concentration is controlled at 50 vol%, the extremely high temperature promotes the evaporation of tungsten. Meanwhile, the active H+ reacts with tungsten to form tungsten hydride (WH), further increasing the evaporation rate of tungsten. According to the above results, the hydrogen arc plasma promotes the simplification of the production process steps of high purity tungsten NPs and reduces the industrialized production cost of high-quality refractory metal NPs.

Modelling and Optimisation of the Sol-Gel Conditions for Synthesis of Semi-Hexagonal Titania-Based Nano-Catalyst for Esterification Reaction

Design and fabrication of a catalyst with the highest activity can be achieved by optimising the synthesis conditions. In this study, the sol-gel synthesis conditions of citric acid concentration, gelling temperature, complex time, and calcination temperature were studied for the preparation of a novel semi-hexagonal calcium/titania-zirconia nano-catalyst used in the esterification reaction. After synthesis of around 24 samples at various conditions, their activity was tested in the esterification reaction and the results were analysed by multi-layer perceptron (MLP) and support vector machine (SVM) models. Both models predicted the actual data with high coefficients of determination, and indicated that the calcination temperature has the most influence on the activity of the prepared semi-hexagonal calcium/titania-zirconia nano-catalyst for the esterification reaction. Moreover, the genetic algorithm (GA) was utilised for optimising the preparation conditions based on the SVM model, due to its higher generalisation capability for prediction. The prepared nano-catalysts under the optimum conditions of 1.42 acid ratio, gelling temperature of 72 °C, complex time of 2.65 h, and calcination temperature of 487 °C showed good crystalline structure and metal–metal and metal–oxygen cation bonding. Finally, the fabricated catalyst had a high surface area (276.5 m2/g) with 3.5 nm pore diameter and almost uniform particle size (80–110 nm) distribution, leading to a high conversion of 97.6% in the esterification reaction, with good catalytic stability up to five times.

Characterization of Defined Pt Particles Prepared by Ultrasonic Spray Pyrolysis for One-Step Synthesis of Supported ORR Composite Catalysts

Polygonal Pt nanoparticles were synthesized using ultrasonic spray pyrolysis (USP) at different precursor concentrations. Physicochemical analysis of the synthesized Pt particles involved thermogravimetric, microscopic, electron diffractive, and light absorptive/refractive characteristics. Electrochemical properties and activity in the oxygen reduction reaction (ORR) of the prepared material were compared to commercial Pt black. Registered electrochemical behavior is correlated to the structural properties of synthesized powders by impedance characteristics in ORR. The reported results confirmed that Pt nanoparticles of a characteristic and uniform size and shape, suitable for incorporation on the surfaces of interactive hosts as catalyst supports, were synthesized. It is found that USP-synthesized Pt involves larger particles than Pt black, with the size being slightly dependent on precursor concentration. Among ORR-active planes, the least active (111) structurally defined the synthesized particles. These two morphological and structural characteristics caused the USP-Pt to be made of lower Pt-intrinsic capacitive and redox currents, as well as of lower ORR activity. Although being of lower activity, USP-Pt is less sensitive to the rate of ORR current perturbations at higher overpotentials. This issue is assigned to less-compact catalyst layers and uniform particle size distribution, and consequently, of activity throughout the catalyst layer with respect to Pt black. These features are considered to positively affect catalyst stability and thus promote USP synthesis for improved properties of host-supported Pt catalysts.

Investigation of structural, magnetic, and electrical properties of Ru doped brownmillerite oxide: KBiFe2O5

We studied and reported the Ruthenium (Ru) doped KBF (KBiFe2O5) multiferroic nanoparticles on structurl, magneitc and electrical properites as a function of dopant and temperature, synthesized through coprecipitation route. X-ray Diffraction spectra of all the samples were indexed with orthorhombic structure (space group P21am) at room temperature and lattice constant decreased with Ru substition. The structural parameters including bond lengths and angles were refined using a standard Rietveld program. Average crystallite measured from schereer method increases with increasing annelaing temperature. Morphology from TEM confirms control over uniform distribution of particle size and shape. Zero field-cooled (ZFC)-Field-Cooled (FC) magnetic measurements reveals superparamagnetic behaviour above room temperature. Magnetic hysteresis loops (M − H) measured at 5 K and 300 K shows improvement with Ru substitution. An insginificant decrease in optical band gap 2.35 to 2.23 eV observed from UV–Vis spectroscopy with Ru substitution. Ferroelectric loops resembling lossy dielectric nature of unpoled samples. Activation energy estimated from DC electrical resistivity was found to be 0.6 eV. Room temperature Dielectric data revelas Maxwell-Wanger type dielectric dispersion and analyzed based on the intrinsic and extrinsic parameters.

Improving Antibacterial Activity of a HtrA Protease Inhibitor JO146 against Helicobacter pylori: A Novel Approach Using Microfluidics-Engineered PLGA Nanoparticles.

Nanoparticle drug delivery systems have emerged as a promising strategy for overcoming limitations of antimicrobial drugs such as stability, bioavailability, and insufficient exposure to the hard-to-reach bacterial drug targets. Although size is a vital colloidal feature of nanoparticles that governs biological interactions, the absence of well-defined size control technology has hampered the investigation of optimal nanoparticle size for targeting bacterial cells. Previously, we identified a lead antichlamydial compound JO146 against the high temperature requirement A (HtrA) protease, a promising antibacterial target involved in protein quality control and virulence. Here, we reveal that JO146 was active against Helicobacter pylori with a minimum bactericidal concentration of 18.8–75.2 µg/mL. Microfluidic technology using a design of experiments approach was utilized to formulate JO146-loaded poly(lactic-co-glycolic) acid nanoparticles and explore the effect of the nanoparticle size on drug delivery. JO146-loaded nanoparticles of three different sizes (90, 150, and 220 nm) were formulated with uniform particle size distribution and drug encapsulation efficiency of up to 25%. In in vitro microdilution inhibition assays, 90 nm nanoparticles improved the minimum bactericidal concentration of JO146 two-fold against H. pylori compared to the free drug alone, highlighting that controlled engineering of nanoparticle size is important in drug delivery optimization.

From modification to mechanism: Supercritical hydrothermal synthesis of nano-zirconia

Nano-zirconia has been widely applied due to its excellent physical and chemical properties (e.g., high strength, corrosion resistance, oxygen ion conductivity). Existing preparation methods of nano-zirconia tend to require long reaction time, and the sizes of final particles are large with uneven distributions. Sub-/supercritical hydrothermal synthesis of nanoparticles is favored by researchers owing to controllable reaction process, uniform particle size distribution, good reproducibility, short reaction time, high conversion rate and harmlessness to environment. In this paper, the characteristics and mechanisms of dissolution, crystallization and growth of nano-zirconia during sub-/supercritical hydrothermal synthesis are systematically reviewed. The influences of process and material parameters on the size and purity of particles are analyzed. Then, the reaction mechanism and product phase transition mechanism during hydrothermal synthesis of zirconia are summarized to provide a theoretical reference for the oriented preparation. Finally, the improvement and commercialization of sub-/supercritical hydrothermal synthesis technology are evaluated, and the future research topics are proposed.

Effects of Needle Coke Conductive Additive on the Performance of Graphite/Resin Composite Plates

AbstractIn this manuscript, the graphite/resin composite plates were prepared via a facile ball milling strategy. The needle coke (NC) as a conductive additive was studied on effects of treated by ball milling on the electrical conductivity, mechanical property of the composite plates. All the characterizations showed that after ball milling, the NC particles have smaller particle size, and more uniform particle size distribution, which enhanced the interfacial adhesion between particles and resin. Due to the difference in shape and size between the auxiliary conductive filler and flake graphite, the addition of NC particles can easily fill the gap between flake‐like graphite and phenolic resin. The uniform distribution of these fillers improves the cross‐linking density, and the conductive path was added between the flake‐like graphite and the resin, which improved the electric conductivity of composit plate from 26.32 S cm−1 to 149.23 S cm−1. Such a prominent performance was attributed to the synergistic effects between the uniformly incorporated NC and the graphite/resin composite adhesive system.

Investigation of the effect of ytterbium doping on photoluminescence and photocatalytic activity of Li4Ti5O12

AbstractThis work reports the combined effect of the morphology and crystallization to investigate the role of Yb3+ as an additive in Li4Ti5O12 crystals on its photocatalytic and photoluminescence (PL) properties. With the pure phase, the synthesized samples have a spherical morphology and spherical structure with good crystallinity and uniform particle size distribution. Li4Ti5O12 doped with ytterbium (Yb3+), were obtained by a new optimized hydrothermal approach. The crystal properties and surface morphology of the synthesized compounds were examined by X‐ray diffraction method and field emission scanning electron microscopy. Bond structures and surface areas were investigated by Fourier transform infrared spectroscopy and Brunauer‐Emmett‐Teller analyses. Finally, the excitation and emission spectra were obtained by a PL spectrophotometer. The PL results show that room‐temperature PL of Yb3+ doped Li4Ti5O12 phosphor has an emission peak at 710 nm which can be attributed to Li4Ti5O12 crystal defect emission. Moreover, it has been found that Yb doping resulted in enhancement of photocatalytic activity, evaluated by monitoring the degradation of methylene blue solution. Note that, 0.01% Yb doped lithium titania phosphor exhibited excellent photocatalytic activity.

Effect of operating conditions on the particle size distribution and specific energy input of fine grinding in a stirred mill: Modeling cumulative undersize distribution

Simulation of the fine or ultra-fine grinding process by Population Balance Model (PBM) has its restrictions because some coarse particles maybe disappear or the breakage rate exhibits complex non-first-order breakage kinetics during the grinding process. In this study, the influence of grinding media diameter, stirrer tip speed, media fulling rate, and powder filling rate on the uniformity of particle size distribution and specific energy input were studied in a stirred mill. The cumulative undersize distribution of ground products was simulated by the Rosin-Rammler-Benne (RRB) function, from which the parameter k and characteristic particle xe of the RRB function were obtained. The time-dependence of the parameter k was investigated. And, the Walker model for describing the reduction in characteristic particle xe with specific energy input was examined. Based on these results, combining the Walker model with the RRB function to simulate the cumulative undersize distribution of ground products. Thereby, a new cumulative undersize distribution of the prediction model was developed, which was successfully validated by the experimental data against predicted data.

Preparation of Piper nigrum Microcapsules by Spray Drying and Optimization with Response Surface Methodology.

To overcome the problems of incomplete flavor components from Piper nigrum extract and the Piper nigrum product easy deterioration in the storage process, microcapsules of the whole Piper nigrum were prepared by spray-drying combined with enzymatic hydrolysis. Under the best conditions for the microencapsulation obtained by the response surface methodology, which have been determined as the ratio of core and wall material (1:0.2, w/w), proportion of wall materials (starch sodium octenyl succinate : maltodextrin : xanthan gum) (1:1:0.2, w/w/w), wall material concentration (11%, w/v) and inlet air temperature (180°C), the embedding rate of the prepared Piper nigrum microcapsules reached 90.21%. Fourier transform infrared spectroscopy, scanning electron microscopy and particle size distribution studies established that the Piper nigrum powder was entrapped within the microcapsules, which had intact morphology and uniform particle size distribution. Besides, gas chromatography-mass spectrometry analysis demonstrated that the prepared Piper nigrum microcapsules could preserve the major of the volatile aroma components of Piper nigrum, carene, D-limonene, α-phellandrene, and (-)-β-pinene. The obtained results showed that the microcapsules might contribute to the development of preserving original flavor from Piper nigrum and have potential applications in the commodity market.

Thermosensitive methylcellulose spray-dried microcapsules as a controlled release carrier for soil management

The excessive use of chemical products in agricultural production has brought many problems such as water pollution, air pollution, soil acidification and eutrophication of water bodies. Biodegradable methylcellulose microcapsules are used as carriers to achieve pollution-free and intelligent controlled release of agricultural chemical products. Methylcellulose was used as a coating material, loaded with fulvic acid (FA) and attapulgite (ATP), and then prepared into microcapsules by spray drying. The preparation process had good repeatability, and the obtained microcapsules possessed uniform particle size distribution. Methylcellulose microcapsules showed good heat sensitivity during water absorption process. The water absorption ratio was more than 10 times that of its own weight at 25°C, and the swelling ratio was 5–7 times that of its own weight at 35°C. The microcapsules reduced the loss of FA nearly 50% during the leaching process. Planting experiments showed that the microcapsules had good biocompatibility and exhibited obvious positive effects on the wheat growth.

Novel Nanocrystal Injection of Insoluble Drug Anlotinib and Its Antitumor Effects on Hepatocellular Carcinoma.

The molecularly targeted agent anlotinib offers a novel therapeutic strategy against advanced hepatocellular carcinoma (HCC). With this study, we aimed to solve the technical problem of anlotinib being insoluble in injectable solutions; we also aimed to assess the antitumor activity of anlotinib on hepatocellular carcinoma cells. We prepared an anlotinib nanocrystal injection by wet grinding, and we optimized the prescription process using a transmission electron microscope (TEM) and a laser particle size analyzer (LPSA). The release of anlotinib from the injected nanocrystals was evaluated using LC-MS/MS in vitro, and the drug’s anti-tumor effects were assessed in a nude mice tumor model. The anlotinib nanocrystals had a uniform particle size distribution (the average nanoparticle size was ~200 nm). The preparation of anlotinib into nanocrystals did not change the original crystal structure. The intravenous injection of anlotinib nanocrystals achieved anti-tumor activity at very low doses compared to those required for oral administration of an anlotinib suspension: anlotinib nanocrystals at a dose of 50 μg/kg inhibited the subcutaneous growth of the HCC cell line MHCC97-H; whereas the dose of anlotinib suspension required for an equivalent effect was 1 mg/kg. Therefore, our novel anlotinib nanocrystal injection preparation provides an option for achieving a safe and effective molecularly targeted therapy against advanced HCC.

Preparation of Nano Cadmium Sulfide and Its Influence on Glomerular Mesangial Cell Apoptosis and NF-κB Expression of Renal Calculus Mice

The study was intended to investigate the influence of nano cadmium sulfide (nCdS) in glomerular mesangial cell (GMC) apoptosis and nuclear factor-kappa B (NF-κB) expression of renal calculus mice. The cadmium acetate and thioacetamide were used to prepare nCdS, which was then characterized by X-ray diffractometer and high-resolution transmission electron microscope for the crystal form, morphology, and particle size. 20 SPF male mice selected as research subjects which were randomly divided into experimental group and control group. Regarding the establishment of renal calculus mouse model, the mice in the experimental group were kept with ordinary feed together with stone attractant (made of ethylene glycol and ammonium chloride), and the mice in the control group were kept with ordinary feed together with tap water. Further, the tetrazolium salt colorimetric method was used to detect the cytotoxicity of nCdS, with Western blot adopted to detect the expression levels of apoptosis-related protein of Bcl-2 and Bax in the two groups of mice, and immunohistochemical staining method applied to detect the expression level of NF-κB in two groups of mice. The results showed that the renal calculus mouse model was successfully established. The prepared nCdS demonstrated a good dispersion property with a regular round shape and uniform particle size distribution between 2.34~10.52 nm. When the concentration of nCdS increased, the survival rate of the GMC decreased, with a notable difference noted (P < 0.05). In contrast with the control group, the expression level of Bcl-2 in the GMC of the experimental group decreased, and that of Bax increased, with the difference found to be notable (P <0.05). The expression of NF-κB in the GMC of experimental group was obviously higher versus that of the control group, and the difference was notable (P <0.05). In conclusions, the nCdS exhibits cytotoxic effects on the GMC in renal calculus mice by promoting the apoptosis of GMC and the NF-κB expression in renal calculus mice.

Synthesis of silver nanoparticles from electronic scrap by chemical reduction

In the present research, the use of electronic waste in the synthesis of silver nanoparticles was investigated. For this purpose, electronic scraps were used as a consumable part to synthesize silver nanoparticles. The results revealed that by optimizing the time and temperature of the dissolution process using nitric acid solution up to 90%, silver can be extracted from these parts. The results indicated that the concentration of initial silver nitrate had a significant impact on the quality of the final product, so that the best conditions for the synthesis of silver nanoparticles with suitable properties were provided at 1 molar concentration. Phase studies indicated that the main phase of the synthesized silver particles had an FCC structure and no unwanted phase was observed. Ultraviolet–visible analysis of the synthesized powder revealed that the main peak for the silver nanoparticles appeared in the wavelength range of 400 to 450 nm. DLS analysis revealed that precursor’s particles inside the sol were below 15 nm. Based on AFM and TEM investigations, the particles synthesized under these conditions had nanometric spherical morphology with uniform particle size distribution.

Effect of Y2O3 on the corrosion resistance of two-step sintered Al5Y3O12-MgAl2O4 sidewalls in the aluminum electrolyte

Magnesium–aluminum spinel (MAS) precursor powder was synthesized through a microwave hydrothermal method. The synergistic effects of sintering process and sintering aids on the densification, hardness and corrosion resistance of MAS were revealed. X-ray diffraction analysis (XRD), Archimedes’ drainage method, fully automatic micro-Vickers hardness test and scanning electron microscopy (SEM) were performed to analyze the phase composition, bulk density, hardness microstructure and corrosion depth of the samples, respectively. Results revealed that the best two-step sintering condition is 1650 °C/3 min/1550 °C/20 h. The MAS products obtained under the best condition have clear grain boundaries, uniform particle size distribution, and few pores. When the amount of Y2O3 added is 4 wt.%, Y2O3 and Al2O3 form the second-phase solid solution Al5Y3O12, which activates the crystal lattice and benefits the sintering densification of MAS. Under these conditions, the relative density of the MAS composite ceramics prepared is relatively large (95.94 %), the grain size is relatively uniform, the hardness is relatively large (1264 HV), and the corrosion depth is relatively small (94.58 μm).