Sub-micro Particles Research Articles

The Combined ICP-MS, ESEM-EDX, and HAADF-STEM-EDX Approach for the Assessment of Metal Sub-Micro- and Nanoparticles in Wheat Grain.

Metal sub-microparticles (SMPs) and nanoparticles (NPs) presence in food is attributable to increasing pollution from the environment in raw materials and finished products. In the present study, a multifaceted analytical strategy based on Environmental Scanning Electron Microscopy and High-Angle Annular Dark-Field-Scanning Transmission Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (ESEM-EDX, HAADF-STEM-EDX) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was proposed for the detection and characterization of metal and metal-containing SMPs and NPs in durum wheat samples, covering a size measurement range from 1 nm to multiple µm. ESEM-EDX and ICP-MS techniques were applied for the assessment of SMP and NP contamination on the surface of wheat grains collected from seven geographical areas characterized by different natural and anthropic conditions, namely Italy, the USA, Australia, Slovakia, Mexico, Austria, and Russia. ICP-MS showed significant differences among the mean concentration levels of metals, with the USA and Italy having the highest level. ESEM-EDX analysis confirmed ICP-MS concentration measurements and measured the highest presence of particles < 0.8 µm in size in samples from Italy, followed by the USA. Less marked differences were observed when particles < 0.15 µm were considered. HAADF-STEM-EDX was applied to a selected number of samples for a preliminary assessment of internal contamination by metal SMPs and NPs, and to expand the measurable particle size range. The multifaceted approach provided similar results for Fe-containing SMPs and NPs. ICP-MS and ESEM-EDX also highlighted the presence of a significant abundance of Ti- and Al-containing particles, while for STEM-EDX, sample preparation artifacts complicated the interpretation. Finally, HAADF-STEM-EDX results provided relevant information about particles in the low nm range, since, by applying this technique, no particles smaller than 50 nm were observed in accordance with ESEM-EDX.

Micro and Macro Flooding Mechanism and Law of a Gel Particle System in Strong Heterogeneous Reservoirs.

To address the issue of ineffective injection resulting from the consistent channeling of injected water through highly permeable channels in ultra-deep, high-temperature, high-salinity, and strongly heterogeneous reservoirs during the production process, a gel particle profile control agent suitable for high-temperature and high-salinity conditions was chosen. With the help of the glass etching visual microscopic model and the heterogeneous long core model, the formation mechanism of a water flooding channeling path and the distribution law of the remaining oil were explored, the microscopic profile control mechanism of the different parameters was clarified, and the profile control effect of macroscopic core displacement was analyzed. The research shows that the formation mechanism of a water flooding channeling path is dominated by the distribution law of the permeability section and the connection mode between different penetration zones. The remaining oil types after water flooding are mainly contiguous block, parallel throats, and multi-branch clusters. The profile control effect of gel particles on reservoir vertical heterogeneity is better than that of reservoir lateral heterogeneity. It was found that 10 wt% submicron particles with a median diameter of 600 nm play a good role in profiling and plugging pores of 5-20 μm. In addition, 10 wt% micron-sized particles with a median diameter of 2.63 μm mainly play a strong plugging role in the pores of 20-30 μm, and 5 wt% micron-sized particles with a median diameter of 2.63 μm mainly form a weak plugging effect on the pores of 10-20 μm. The overall profile control effect of 10 wt% submicro particles is the best, and changes in concentration parameters have a more significant effect on the profile control effect. In the macroscopic core profile control, enhanced oil recovery (EOR) can reach 16%, and the gel particles show plugging, deformation migration, and re-plugging. The research results provide theoretical guidance for tapping the potential of the remaining oil in strong heterogeneous reservoirs. To date, the gel particles have been applied in the Tahe oilfield and have produced an obvious profile control effect; the oil production has risen to the highest value of 26.4 t/d, and the comprehensive water content has fallen to the lowest percentage of 32.1%.

Ultrasound Supported Galvanostatic Deposition of Zn Coatings Reinforced with Nano-, Submicro-, and Micro-SiC Particles-Weak Acidic Chloride Baths.

In this paper, we present results concerning the electrochemical deposition of Zn-SiC composite coatings reinforced with nano-, submicro-, and microparticles. The influence of current density, particle size, and ultrasound on functional parameters which are especially important from a practical point of view (i.e., concentration of particles in coatings, current efficiency, morphology, reflectivity, roughness, hardness, and corrosion resistance) are investigated and discussed. Coatings were deposited from commercial, chloride-based electrolytes dedicated for the deposition of Zn coatings in a weakly acidic environment. Electrodeposited composites contained up to 1.58, 4.08, and 1.15 wt. % of SiC for coatings reinforced with nano, submicro, and micrometric particles, respectively. The process proceeded with relatively high efficiency, exceeding 80% in almost all cases. The results indicate that ultrasounds strongly increase Faradaic efficiency and affect the kinetics of electrode processes and the properties of synthesized coatings. Moreover, the obtained results show that it is possible to synthesize composite coatings with slightly higher mechanical properties while retaining corrosion resistance compared to metallic Zn coatings.

Impacts of sub-micrometer sediment particles on early-stage growth and survival of the kelp Ecklonia bicyclis

Marine forests have declined in many urbanized regions in recent years. One cause is the inflow of fine particles into coastal rocky shores. We examined the influence of sub-micrometre (sub-micro) particles on the early growth stages of the large brown macrophyte Ecklonia bicyclis. The percentage of substrate attachment of zoospores decreased with an increase in sub-micro sediments. As the size of the particles decreased, the negative effect became greater. There was an increase in poor levels of gametophyte survival and growth as more and smaller sediment was deposited. We consider that the causes of these phenomena owing to increasing amounts of sediment is a decrease in availability of substrate for zoospore attachment and that of area for substance exchange on the gametophytes. We also evaluated the effects in sea areas, based on the amount and size distribution of seabed sediment in the algal communities deforested by particles, and found that the inhibition of zoospore attachment and gametophyte growth by sub-micro particles was remarkably large. The sub-micro sediment on the substrate has seriously negative effects on the early stages of macrophytes. Inflow of very fine particles to natural marine forests may result in severe degradation of rocky reef ecosystems.

The Chitosan-Sodium Alginate Submicro Particles Loading Herbal of Ethanolic Exract of Leaves Senna Alata. L for Curing of Bacterial Infection on Skin

Abstract&#x0D; Mardiyanto 1*, Indah Solihah 1, and Thio Gunawan Jaya 1&#x0D; 1Department of Pharmacy Faculty of Science Sriwijaya University &#x0D; *Corresponding Author : mardiyantoUNSRI@gmail.com&#x0D; This research was performed to detect the activity of the optimum formula of chitosan and sodium alginate submicro particles loading of the ethanol extract of leaves ketepeng cina (Senna alata L.) to P. acne growth. Submicro manufactured particles was used three variations of the formula from three of volume used of calcium chloride (CaCl2): 20, 40, and 100 mL based on ionic gelation method. The results obtained of %EE in formulas 1, 2 and 3 were 78.56%, 81.71%, and 77.48%. Formula 2 with a value of % EE of 81.71% was used as an optimum formula which indicates that the particles are well protected by chitosan and sodium alginate polymers so as to prevent particle damage during the homogenization process. The results of the diameter measurements showed that the optimal formula enters in the submicro particle range with the value obtained is 525,9455 nm. The submicro formula of chitosan alginate particles loading the ketepeng cina leaf ethanol extract was barely homogeneous which based on the results obtained by the PSA was 0.433 of PDI. The zeta potential value was +3.5 mV. The results of X-ray diffraction analysis or X ̶ Ray Diffraction produce a pattern shaped amorph with the resulting peak does not have a wide distance and pattern. In vivo testing using ketepeng cina leaf extract as submicro was decreased the P. acne lesion faster than using only ketepeng cina leaf extract because the submicro particle preparation has a small particle that is below to 600 nm making it easier to penetrate the skin pores to reach the target. The results of the analysis of the curing of many lesions on the skin of mice have a significance value of homogeneity. The one-way ANOVA test of &lt; 0.05 was a significant effect of the test group on the decreasing in the number of lesions on the skin of the mouse.&#x0D;

Facile synthesis and photoluminescence performance of Er3+-activated BiOF sub-micro particles for ratiometric thermometers

A series of the Er3+-activated BiOF sub-micro particles were successfully synthesized by means of a facile technology of solid-state reaction route so as to explore new thermometric materials. The phase structure and microstructure information of the designed samples were verified by the X-ray diffraction, field-emission scanning electron microscope and transmission electron microscope. The whole sub-micro particles can emit bright green emission with high color purity of 79.3% when excited by 378 nm and the optimal doping concentration for the Er3+ ions in the BiOF host lattices was 7 mol%. Based on the calculation results, one knows that the concentration quenching mechanism was contributed by the electric dipole-dipole interaction and the critical distance between the Er3+ ions in the BiOF host lattice was 15.5 Å. Furthermore, the temperature dependent fluorescence intensity ratio of the green emissions arising from the thermally coupled levels (i.e., 2H11/2 and 4S3/2) was studied so as to explore the feasibility of the resultant sub-micro particles for optical thermometers. The maximum absolute and relative sensitivities of the designed nanoparticles were 0.0051 K-1 and 1.11% K−1, respectively, implying that the Er3+-activated BiOF sub-micro particles were promising candidates for ratiometric thermometers.

Electrocataytic oxidation of ascorbic acid and uric acid on a Tb-doped Ta2O5 modified glassy carbon electrode

Terbium-doped tantalum pentoxide (Tb–Ta2O5) sub-micro particles are prepared with the hydrothermal method at 200 °C. X-ray diffraction reveals that Tb–Ta2O5 sub-micro particles are orthorhombic and the Ta2O5 cell shrinks after Tb doping. X-ray photoelectron spectroscopy implies Tb3+ form on the Tb–Ta2O5 surface. The electrocatalytic property of Tb–Ta2O5 coated glassy carbon electrode (Tb–Ta2O5/GCE) is performed using cyclic voltammetry in 0.1 M phosphate buffer solution (PBS, pH = 7.0) containing ascorbic acid (AA) or uric acid (UA). Tb–Ta2O5/GCE displays high electrochemical catalytic property toward AA and UA oxidation, indicating potential applications toward AA and UA detection.

Emission characteristics of particulate matters from a 30 MW biomass-fired power plant in China

The emission characteristics of particulate matters from a full-scale biomass-fired power plant equipped with bag filters were investigated. Results show that particle size distribution at the inlet of bag filter from the combustion of blended feedstocks is bimodal, while that of dry bark feedstocks is essentially unimodal with negligible emission of coarse particles with diameter in the range of 1.0–10 μm. The combustion of blended fuels generates higher yields of submicro particles than that of dry bark feedstocks. Elemental analysis shows that submicro particles in all cases mainly consist of potassium, chlorine, and sulfur. Higher chlorine but lower sulfur contents are observed in submicro particles from blended fuels compared with that from dry bark feedstocks. The vibrating operation of grate furnace reduces submicro particles emission as well as the sulfur content in all particles. Ion chromatography results show that sulfate ion and chloridion are the two most abundant water-soluble anions in particulate matters, while water-soluble cations are richest in potassium with considerable content of calcium, magnesium, sodium and ammonia. The contribution of organic and element carbon in particulate matters is in the range of 1–3%, indicating high combustion efficiencies and low organic and element carbon emissions of biomass-fired grate furnaces.

New electrostatic precipitator with dielectric coatings to efficiently and safely remove sub-micro particles in the building environment

The influx of ambient particulate matter (PM) to the indoor environment has threatened human health due to its adverse impacts on respiratory, cardiovascular, and neurological systems. Consequently, PM removal devices with high efficiency and low cost like electrostatic precipitator (ESP) are essential for a healthy and sustainable indoor environment. Traditional two-staged ESP includes particle charging and collection part. In this study, we innovated the collection part by coating the repelling electrodes with dielectric films. Four performance influencing parameters were examined: the voltage difference (Vc) and distance (dc) between the repelling and collecting electrodes, and both the dielectric material and thickness (de). The new ESP achieved its best performance when coated with PET (de =60 μm) at dc =3 mm. The breakdown voltage was promoted from −4 kV (without dielectric film) to −9 kV, and PM removal efficiency was enhanced from 60 % to 92 %. The new ESP had low net ozone production (3–5 ppb), low pressure drop (10–13 Pa), and low energy consumption (18 W/m2), making it an eco-friendly device. Running continuously for one week, the new ESP maintained a single-pass PM removal efficiency of around 90 %, notwithstanding changes in ambient air temperature and relative humidity.

Sulfonated porous surface of tantalum pentoxide/polyimide composite with micro-submicro structures displaying antibacterial performances and stimulating cell responses

To improve the surface bio-performances of polyimide (PI), tantalum pentoxide (Ta2O5)/PI composites (TPC) were prepared, and concentrated sulfuric acid was utilized to modify TPC surface. The results revealed that sulfonated TPC (STPC) exhibited microporous surface with pores size of about 3 μm, and sulfonic acid (-SO3H) groups were introduced onto the microporous surface. In addition, many Ta2O5 submicro particles appeared on the microporous surface, which formed micro-submicro structures. Compared with PI, the surface roughness, hydrophilicity, surface energy and protein adsorption as well as apatite mineralization of STPC in simulated body fluid were obviously enhanced, which increased with Ta2O5 content increasing. In addition, STPC exhibited antibacterial performances due to the presence of -SO3H groups and Ta2O5. Furthermore, the responses (adhesion, proliferation and differentiation) of rat bone marrow mesenchymal stem cells to STPC were remarkably promoted with the increase of Ta2O5 content. In short, STPC with 50w% Ta2O5 content (STPC 50) with sulfonated microporous surface contained micro-submicro structures, which exhibited antibacterial performances and stimulated cell responses. STPC50 with improved surface properties and cytocompatibility might have large potentials for bone repair applications.

Thermoplastic starch and bioactive chitosan sub-microparticle biocomposites: Antifungal and chemico-physical properties of the films

In this study, chitosan (C) tripolyphosphate (T) sub-micro particles containing ungeremine (CTUn), an alkaloid particularly active against Penicilliumroqueforti, a fungus responsible of the bakery products deterioration, were prepared through external gelation crosslinking process. The particles were included in a thermoplastic starch based polymer Mater-Bi (MBi), and MBi/CTUn bioactive biocomposites were obtained. The films showed bioactivity against P. roqueforti. In particular, the bioassays were performed on films with different concentration of CTUn and at different pH values. CTUn particles influenced MBi crystallization (DSC analysis) and promoted thermal degradation of MBi starch component (TGA). Morphological analysis confirmed even distribution of sub-micro particles into the polymeric matrix. Water permeability slightly increased, as expected, whereas oxygen permeability decreased. Tensile tests showed CTUN sub-microparticles improved rigidity and tensile strength of the films at the expense of ductility. Finally, MBi/CTUn biocomposites evidenced interesting performances potentially exploitablein bioactive bakery based food packaging materials.

Mesoporous bioactive glasses for the combined application of osteosarcoma treatment and bone regeneration.

In this study, mesoporous bioactive glass (MBG) sub-micro particles were prepared through sol-gel synthesis and possessed a uniform and spherical structure with particle size of 302 ± 43 nm, a pore size of 4 nm and a high surface area of 354 m2 g-1. Alendronate (AL) is often used for the treatment of bone associated diseases, in particular osteosarcoma. However, due to the low bioavailability and high toxicity at increased doses, local and sustained release would be an ideal approach to AL delivery. Here, MBGs and aminated MBGs (AMBG) were applied as carriers for AL loading. High encapsulation efficiency of 75% and 85% and loading efficiency of 60% and 63%, for MBG and AMBG, respectively, was achieved. The release profile of AL from AMBG showed a better sustained and controlled release mechanism compared to MBG. In vitro results demonstrated the non-cytotoxic nature of both MBG and AMBG following exposure to MG63 osteoblast like cell line. AL release from MBG and AMBG, even at lower concentration, provoked decreased MG63 proliferation. The osteogenic potential of MBG and AMBG following exposure to dental pulp stem cells was evaluated using alizarin red assay.

Slow release formulation of herbicide metazachlor based on high molecular weight poly(lactic acid) submicro and microparticles

Frequently used pre-emergent herbicide metazachlor was encapsulated into high molecular weight poly(lactic acid) particles, and its subsequent release and the effectivity of such formulations were investigated. Two sets of polymeric micro- and submicro particles, both with the theoretical metazachlor loading of 20%, 30%, and 40%, were prepared and characterized. Loading efficiency reached 80% for both types of particles. Release profiles were tested in vitro for the individual particle variants and were shown to have a bimodal profile with the initial fast burst release and much slower second phase. Finally, selected formulations were tested in vivo against target plants (field poppy and barnyard grass) and non-targets plants (mustard and rapeseed) and showed improved inhibition of target plants (about 30% higher for barnyard grass) and at the same time lower inhibition of non-target plants (rapeseed) in comparison with the identical dose of metazachlor alone.

Numerical investigation on deposition process of submicron particles in collision with a single cylindrical fiber

In this paper, a numerical study on the deposition behaviour of micro-particles on a solid surface has been carried out using the CFD-DEM coupled with in-house subroutines. We introduce a particle interaction model to predict the dynamic deposition behaviour. The model predicts the formation of the dendrites and the dynamic progression of the deposition very well. For the sub-micro particles which are dominated by the diffusion and interception mechanism, it is found that the particles are captured by the fibers and deposited on the surface of the fiber uniformly at the initial stage. With increasing deposited particles, the small agglomerates grow up to branched dendrites. Some of the particles are distributed on the surface of the fiber and the others are distributed on the particle dendrites. The effects of inlet flow velocity, particle diameter as well as fiber diameter on the deposition morphology and the collection efficiency are investigated comprehensively. The results indicated that a high collection efficiency could be achieved at relative smaller fluid velocity and bigger particle diameter. Meanwhile, the normalized pressure drop and the velocity gradient on both sides of the fiber increase with SVF. Such an increase in the pressure drop and velocity gradient contribute to a larger collection efficiency.

Enhancing the performance of metakaolin blended cement mortar through in-situ production of nano to sub-micro calcium carbonate particles

Metakaolin has emerged as a popular supplementary cementitious material to partially replace ordinary Portland cement (OPC) due to its high pozzolanic reactivity and surface area. In this study, a new method, pre-carbonation method, is proposed to exploit the synergistic effect between the metakaolin blended cement and calcium carbonate so that the performance of the cement mortar can be further improved. This new method in-situ produces nano to sub-micro calcium carbonate particles in a slaked lime slurry through bubbling carbon dioxide. The produced carbonated slurry is then mixed with other ingredients of the mortar. The in-situ produced nano to sub-micro calcium carbonate particles possess high reactivity due to their high surface area, leading to faster and more complete reaction between the cement and the calcium carbonate. Experimental studies show both the mechanical properties and durability of the metakaolin blended mortar have been improved by the proposed method. The calorimetry results show that the carbonated slaked lime slurry can accelerate the hydration of the metakaolin blended cement due to the extra heterogenous nucleation sites provided by the calcium carbonate nano to sub-micro particles. TGA/XRD results suggest that more ettringite is produced in the mortar/concrete with pre-carbonated slaked lime slurry, which increases the total volume of the hydration products, leading to a denser microstructure of the mortar/concrete. All these findings suggest that in-situ production of nano to submicro calcium carbonate particles provides a viable way to improve the performance of metakaolin blended cement.

N-halamine/pyridinium-derivatized magnetic sub-microparticles with synergetic biocidal properties

Dual biocidal groups of N-halamine and pyridinium were used to modify surface of magnetic sub-microparticles to exert enhanced synergistic antibacterial capacity. Magnetic silica Fe3O4 sub-microparticles (SMPs) were synthesized and then encapsulated with interpenetrating polymer network (IPN) of polystyrene (PS) and poly(acrylic acid) (PAA). The carboxylic acid groups of PAA were used as surface reactive sites to bond with amino groups of 4-aminopyridine through amidation reaction. N-halamine/pyridinium-derivatized magnetic sub-microparticles were sequentially produced by quaternization of the pyridine to pyridinium with 1-chlorohexane and chlorination of amide N–H to N-halamine with NaClO. The synthetic steps and products were characterized with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectrocsopy (XPS). The N-halamine/pyridinium-derivatized SMPs with dual biocidal functionalities showed faster deactivation abilities against both Escherichia coli and Staphylococcus aureus compared with their counterparts that contained only N-halamine or pyridinium, and exhibited promising stability toward repeated washing and long-term storage. The designed SMPs in this study offer potential and ideal candidates for sterilization application due to multiple advantages including improved synergistic biocidal ability, high surface area, and easy recyclability.

Qualification of an Ultrasonic Instrument for Real-Time Monitoring of Size and Concentration of Nanoparticles during Liquid Phase Bottom-Up Synthesis

Both in design and production of nanoparticles and nanocomposites it is of vital importance to have information about their size and concentration. During the formation of nanoparticles, real-time monitoring of particle size and concentration during bottom-up synthesis in liquids allows for a detailed study of nucleation and growth. This provides valuable insights into the formation of nanoparticles that can be used for process optimization and scale up. In the production of nanoparticles, real-time monitoring enables intervention to minimize the number of off-spec batches. In this paper we will qualify an ultrasound nanoparticle sizer (UNPS) as a real-time monitor for the growth of nanoparticles (or sub-micro particles) in the 100 nm–1 µm range. Nanoparticles affect the speed and attenuation of ultrasonic waves in the dispersion. The size of the change depends, amongst other things, on the size and concentration of the nanoparticles. This dependency is used in the UNPS method. The qualification of the UNPS was undertaken in two successful experiments. The first experiment consisted of static measurements on commercially available silica particles, and the second experiment was real-time monitoring of the size and concentration during the growth of silica nanoparticles in Stöber synthesis in a water–alcohol mixture starting from the molecular precursor tetraethyl orthosilicate. The results of the UNPS were verified by measurements of a dynamic light scattering device and a transmission electron microscope.

Chemical-looping water splitting over ceria-modified iron oxide: Performance evolution and element migration during redox cycling

Ceria-modified iron oxide exhibits high redox performance superior to that of pure iron oxide, which can inhibit the deactivation caused by sintering of materials. In the present work, the ceria-modified iron oxide is investigated as an oxygen carrier for hydrogen production via chemical-looping water splitting process (CLWS). To identify the role of CeO2, the performance evolution and element migration of the mixed oxides during redox cycling were discussed in detail. Comparing the obvious deactivation of pure iron oxide sample, ceria-modified iron oxide shows relative constant production of hydrogen during the successive recycling water splitting. FeCe20 sample with a CeO2 mole percent of 20% shows the highest average yield of hydrogen (8651 μmol/g) with a Fe average oxygen recovery rate of 67.7% among Fe-Ce mixed oxides with different Ce molar percentage (x = 0, 10, 20 and 40%). In spite of materials sintering, the oxygen releasing/acquiring capacity and reactivity of Fe-Ce mixed oxides are three times higher than that of pure iron oxide after redox treatment. This can be ascribed to the preferable dispersion of Ce-based sub-micro particles (CeO2 and CeFeO3) and enhanced Fe-Ce interactions generated from active sites at the contact interface between iron oxides (mainly Fe3O4 particles) and Ce-based sub-micro particles (CeO2 and CeFeO3) after cycling.

The rheological behaviors and morphological characteristics of different food hydrocolloids ground to sub-micro particles: in terms of temperature and particle size

Temperature sweep tests and steady shear properties of five different food hydrocolloids (guar gum, xanthan gum, carboxymethylcellulose, pectin and carrageenan) in two different particle sizes groups have been determined at 25, 40, 60 and 80 °C in 1% aqueous solution. Also, the Scanning Electron Microscopy (SEM) images of gums were taken to investigate the morphological properties of the samples. The particle size and processing temperature significantly affected all rheological parameters of the hydrocolloid solutions. The flow behavior of the samples was fitted to Ostwald de Waele model (R2 = 0.959). The highest n value was recorded at 60 °C for all samples. The most drastic changes in consistency coefficient (K) values of the samples were observed in carrageenan solution and it was ranged from 0.013 to 1.774 Pa.sn before the size reduction and from 0.007 to 0.337 Pa.sn after the size reduction process. As the consistency coefficient (K) and apparent viscosity (η50) decreased with the temperature, the flow behavior index increased in both group of samples. As a result, it was concluded that the increase in processing temperature and size reduction process caused a decrease in resistance of hydrocolloid solutions subjected to the deformation, which is a very important factor affecting the quality and good mouth-feel of products.

High-energy ball-milling combined with annealing of TiC powders and its influence on the microstructure and mechanical properties of the TiC-based cermets

High-energy ball-milling and annealing processes greatly affect the grain size, composition and microstrain of the TiC powders, which play a key role in determining the final microstructure and properties of TiC-based cermets. In this work, TiC-25WC-11Mo2C-18(Ni-Co) cermets were fabricated with four types of TiC powders: microsized (raw), nanosized (milled) and submicron (heated in vacuum at 1350 or 1450℃). Effects of crushing and subsequent heat treatments on the composition and structure of TiC powders were investigated. Morphology and mechanical properties of the cermets were also studied. Annealing decreased the microstrain and oxygen content of the milled TiC, forming submicro particles with high crystallinity. Activated particles accelerated the dissolution-precipitation process and interface reaction of the core-rim phases, leading to thick rims on small TiC cores. Chemical bonded oxygen in TiC grains could only be consumed via full interface reaction of the core-rim structure, leaving small pores in ceramic grains. Spherical TiC grains with uniform and integrated inner rims were observed in samples with annealed powders. Ultrafine TiC-based cermets with high strength (1862MPa), hardness (92.1 HRA) and satisfied toughness (11.32MPamm1/2) were achieved using these annealed submicron TiC powders.