Silica Silicon Research Articles

Chemical and Mineralogical Composition Analysis of Different Nigerian Metakaolins

In this work, four different metakaolin samples (C01, A6060, B6075, and C12090) were investigated to determine their constituent elements and the relative quantities of the oxide contents associated with each of the elements. Kaolin samples were collected from different sites at Okpella, a village in the Edo state of Nigeria, West Africa. The metakaolin was produced by calcination at 750℃, which was followed by the dealumination process. The prepared samples were characterized by Field Emission Scanning Electron Microscope (FE-SEM), Energy Dispersive X-ray Spectroscopy (EDS), Fourier Transform Infrared Resonance (FTIR) spectroscopy, and X-ray diffraction (XRD) technique. Digital images were obtained and analyzed to determine the texture and porosity of the samples. FE-SEM images showed a slight difference in the morphology of the samples. Differing percentages of metal oxides were determined from the samples using EDS analysis. The major oxides present in all the samples were Silica (Silicon oxide) and Alumina (Aluminium dioxide). Aluminium was completely absent in C12090 but had a large percentage of silicon (36%).

Hydrogen-bonded silicene nanosheets of engineered bandgap and selective degradability for photodynamic therapy

Silicon, a highly biocompatible and ubiquitous chemical element in living systems, exhibits great potentials in biomedical applications. However, the silicon-based nanomaterials such as silica and porous silicon have been largely limited to only serving as carriers for delivery systems, due to the lack of intrinsic functionalities of silicon. This work presents the facile construction of a two-dimensional (2D) hydrogen-bonded silicene (H-silicene) nanosystem which is highlighted with tunable bandgap and selective degradability for tumor-specific photodynamic therapy facilely by surface covalent modification of hydrogen atoms. Briefly, the H-silicene nanosheet material is selectively degradable in normal neutral tissues but rather stable in the mildly acidic tumor microenvironment (TME) for achieving efficient photodynamic therapy (PDT). Such a 2D hydrogen-bonded silicene nanosystem featuring the tunable bandgap and tumor-selective degradability provides a new paradigm for the application of multi-functional two-dimensional silicon-based biomaterials towards the diagnosis and treatments of cancer and other diseases.

Study of the effects of Silicea terra and Zincum metallicum in various dilutions on the oxidative activity of macrophages in vitro

Silica (silicon dioxide) is found in nature, being composed of 2 chemical elements abundant on the Earth's crust, oxygen and silicon. As homeopathic medicine, silica is used for treatment of chronic ulcers due to its ability to modulate the macrophage activity. Zinc is a cofactor of several immune mediators, especially thymulin, which is also capable of modulating the macrophage activity and recruitment of B1 cells in mice. In the present study, we assessed the homeopathic medicines Silicea terra and Zincum in an in vitro experimental model to determine their effects on the interaction between RAW 264.7 macrophages and BCG (Bacillus Calmette-Guérin). In this step of the study, we assessed oxidative activity through measurement of hydrogen peroxide and nitrite/nitrate in the cell culture supernatant after 24 hours of treatment. Several homeopathic potencies were used for both drugs (6cH, 30cH, 200cH). The tests were performed in duplicate, and the data were analyzed by means one-way ANOVA. The results show no effect on nitric oxide (NO) production, but reduction of hydrogen peroxide production (p≤ 0.001) after treatment with the vehicle (0.03% alcohol). Such reduction was reversed with treatments Silicea terra30cH and Zincum metallicum 30cH (p≤ 0.001). Treatment with Silicea terra 200cH induced significant reduction of hydrogen peroxide production, even when compared to the vehicle (p≤ 0.005). Taken together, the results indicate that only treatment of BCG-challenged macrophages with Silicea terra 200cH was able to significantly reduce the oxidative activity of these cells after 24 hours of incubation. Since NO production in vitro usually occurs after 96 to 120 hours of incubation, one might infer that the negative result obtained in the present study might be associated with the time-point of assessment. Other aspects of the macrophage-BCG interaction are still under evaluation.

Akhiezer mechanism dominates relaxation of propagons in amorphous material at room temperature

Propagons play an important role in tuning the thermal conductivity of nanostructured amorphous materials. Although advances have been made to quantitatively evaluate the relaxation time of propagons with molecular dynamics, the underlying relaxation mechanism remains unexplored. Here, we investigate the relaxation process of propagons in amorphous silicon, amorphous silica, and amorphous silicon nitride at room temperature in terms of the Akhiezer model, the parameters of which were evaluated by performing lattice dynamics and molecular dynamics analysis. The results show that the Akhiezer model can well reproduce experimental results obtained by various types of measurement methods, indicating that the Akhiezer mechanism dominates the relaxation process of propagons at room temperature. Moreover, we show that the appropriate sound speed of propagons is around 80% of the Debye sound speed and comparable to the transversal sound speed. We also reveal that diffusons’ contribution to thermal conductivity of these amorphous materials is similar, which is around 1 W/m K, whereas propagons’ contribution to the overall heat conduction varies significantly depending on the materials: it is 30% in amorphous silicon and silica but as high as 70% in amorphous silicon nitride. The Akhiezer mechanism offers a deeper understanding of propagon heat transport and sound attenuation in amorphous materials.

Silicon, an important exposure marker in vivo in silicosis research.

The degree of silicosis exposure is closely related to the progress of silicosis. At present, we use animal and human studies to explore whether silicon can be an important exposure marker in the development of silicosis. Rats were randomly divided into 2 groups: (1) controls; and (2) silicosis. Rats in the silicosis group were killed at 4, 8, 12, 16, 24h, 3, 7, 14, 21, and 28days. Hematoxylin-eosin (HE) and immunohistochemistry (IHC) were performed to observe the histomorphology of lung tissue. The expression levels of CC16 and SP-D were detected using ELISA kits. In addition, we conducted a population study. Workers who have been selected to work in an iron mine for more than 1year as research objects. The population was divided into four groups: silicosis exposure group (workers exposed to silica dust for more than 1year in an iron mine were selected); patients group (silicosis patients); observation group (evidence of disease not meeting formal diagnostic criteria) and control group. Both the levels of trace silicon in the urine and blood of rats and human subjects were measured with ICP-MS. Serum levels of silicon were immediately increased in rats exposed to silicon dust. Similarly, our population study revealed that the silicon level in the silica exposure group and the observing group (exposed but no obvious symptoms) were significantly increased over that of the control group (P < 0.05). In subjects with extended exposure to silica, the serum and urine silicon level in exposed workers appeared to rapidly increase, reaching its peak in 1-5years, followed by a gradual decline thereafter. Workers exposed to dust for less than 10years were divided into subgroups by 2-year limit. The levels of serum silicon, urine silicon, TGF-β1, and TNF-α were significantly higher than that of control group. Changes of the serum levels of silicon occurred earlier than the expression of cytokines such as TNF-α, TGF-β1, CC16, and SP-D. The level of silicon in workers rapidly increased after exposure to silica, and the change occurred before the expression of TGF-β1 and TNF-α. As a whole, the findings suggest that determining the level of silicon in vivo might be an effective exposure marker in the diagnosis and pathogenesis of silicosis.

Rice husk-based adsorbents for removing ammonia: Kinetics, thermodynamics and adsorption mechanism

Volatile organic compounds (VOCs) and odor are the main indoor air pollutants that can have impact on human health. In this study, the ammonia adsorption behaviors onto the three adsorbents from biomass rice husks, including silica carbon composite (RH-SiO2-C), activated carbon (RH-AC) and silicon dioxide (RH-SiO2) were investigated by time-resolved infrared spectroscopy. It was found that 85% of the initial concentration was eliminated under the optimized conditions. The adsorption capacity of ammonia onto RH-SiO2-C, RH-AC and RH-SiO2 at 298 K were found to be 7.28 mg g−1, 11.22 mg g−1 and 6.61 mg g−1, respectively. The pseudo-second-order model fit the kinetic data well for all the adsorbents and the adsorption rate constants were calculated. Thermodynamic activation parameters were obtained by studying the adsorption behavior at different temperatures, the activation energy values of ammonia adsorption onto RH-SiO2-C, RH-AC and RH-SiO2 were calculated to be 38.80 kJ mol−1, 19.24 kJ mol−1 and 54.64 kJ mol−1, respectively. The activation enthalpy (ΔH#), entropy (ΔS#) and Gibbs free energy (ΔG#) were also determined. Inverse gas chromatography (IGC), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS) and surface area experiment were conducted to propose possible adsorption mechanisms. Beside surface area related with porous structures, chemisorption based on Lewis acid-base reaction may be a crucial interaction between ammonia and the adsorbents. This study gains insights into the adsorption of ammonia onto the biomass rice husk-based adsorbents, which inspires the further design of adsorbents to effectively remove VOCs and odors, therefore achieving a high efficiency for air pollution control.

In vitro and in vivo blood compatibility of concentrated polymer brushes.

Concentrated polymer brushes (CPBs) and semi-dilute polymer brushes (SDPBs) of poly(2-hydroxyethyl methacrylate), poly(2-hydroxyethyl acrylate), poly[poly(ethylene glycol)methyl ether methacrylate] (PPEGMA) and poly(2-methoxyetyl acrylate) were prepared on silica particles and silicon wafers by surface-initiated atom transfer radical polymerization (SI-ATRP). In order to evaluate in vitro blood compatibility, plasma protein adsorption on the brushes was quantified with a BCA protein assay, and the adsorbed proteins on the brushes were identified using high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). All four CPBs displayed much less protein adsorption than their corresponding SDPBs. Interestingly, the number and type of identified proteins differed on the brushes. Platelet adhesion was then examined on the brushes, whereby CPBs suppressed platelet adhesion to a greater extent than the corresponding SDPBs, although platelet activation was observed on all surfaces. As a result, the CPBs of PPEGMA prevented platelet adhesion the most. After screening the polymers by in vitro evaluation, CPBs of PPEGMA were then grafted on a catheter by SI-ATRP. The catheter with the CPBs was implanted into the jugular vein of a rabbit. The in vivo assessment after three weeks of implantation confirmed that the CPBs caused little coagulation or inflammation, whereas the pristine catheter exhibited inflammation and encapsulation.

Summertime Biogenic Silica Production and Silicon Limitation in the Pacific Arctic Region From 2006 to 2016

AbstractWe present a decade of dissolved and particulate silica concentrations within five biological “hot spots” in the Pacific Arctic Region (PAR) and the first measurements of both biogenic silica production rates (ρSi) and the kinetics of silicon utilization from a period of four years at the same sites. The “hot spots” were located within the Bering and Chukchi Seas and identified as part of the Distributed Biological Observatory (DBO). Across all hot spots, the highest concentrations of silicic acid (Si(OH)4) and biogenic silica were found near the bottom of the euphotic zone and often correlated with increased ρSi. For the entire region, the average ρSi was 19 mmol m−2 day−1 and siliceous microplankton (i.e., diatoms) contributed an average of 62% to primary productivity and 82% to nitrate utilization. Irradiance and [Si(OH)4] had separate and interactive effects on ρSi. Irradiance modulated both the magnitude of ρSi and the response of diatoms to changes in Si(OH)4. Availability of Si(OH)4 limited ρSi in all hot spots in at least one of the four years. Kinetic experiments conducted in all hot spots demonstrated that the half‐saturation constant (Ks) for ρSi was 4–8 times higher than ever reported in the literature. In the southeastern Chukchi Sea, an east to west gradient in [bSiO2] and ρSi may have been driven by differences in the availability of NO3− rather than Si(OH)4. Despite strong interannual variability, we suggest that phytoplankton phenology responds to short‐term climatic changes, which can have far‐reaching effects on Arctic regions influenced by the Pacific‐origin waters flowing through the PAR.

Common Background Signals in Voltammograms of Crystalline Silicon Electrodes are Reversible Silica-Silicon Redox Chemistry at Highly Conductive Surface Sites.

The electrochemical reduction of bulk silica, due to its high electrical resistance, is of limited viability, namely, requiring temperatures in excess of 850 °C. By means of electrochemical and electrical measurements in atomic force microscopy, we demonstrate that at a buried interface, where silica has grown on highly conductive Si(110) crystal facets, the silica-silicon conversion becomes reversible at room temperature and accessible within a narrow potential window. We conclude that parasitic signals commonly observed in voltammograms of silicon electrodes originate from silica-silicon redox chemistry. While these findings do not remove the requirement of high temperature toward bulk silica electrochemical reduction, they redefine for silicon the potential window free from parasitic signals and, as such, significantly restrict the conditions where electroanalytical methods can be applied to the study of silicon surface reactivity.

ESTIMATION THE FACTORS AFFECTING ON GROWTH OF ALGAE IN UM EL-NAAJ LAKE BY USING REMOTE SENSING TECHNIQUES

Epiphytic algae adherent to aquatic plants are an essential link in the composition of the food chain of any ecosystem. Epiphytic algae act as primary producers of the food chain in the aquatic ecosystem and as natural food for herbivorous zooplankton and fish. This study aimed to detect the presence of algae colonies through remote sensing and to analyze factors that affect the growth of algae through field survey and visual interpretation of satellite images in Lake Um El-Naaj. Samples were collected from six locations on Lake Um El-Naaj from November 2018 to June 2019. The algae samples were collected from submerged parts of emerging aquatic plants (aquatic macrophytes Phragmites australis) and stored in plastic bags with little ambient water and solutions for preservation in the field and the laboratory. Water samples were collected to study the nutritional factors that influence the growth of algae, including the concentration of Phosphate, Nitrate, and Silica (silicon dioxide). The results showed that the values of total phosphorus increased by 1.0, 0.9, and 0.8 mg/L, in January, in places 2, 5, and 6, respectively. The highest nitrate value was 11.2 mg/L in December at site 5, while the lowest concentration values were in November (2.2 mg/L at site 6 and 3.7 mg/L at site 4). Besides, the lowest silicate concentration was 0.4 mg/L in November at site 2, while the highest was 2.4 mg/L in June 2019 at site 6. Based on the findings, it is possible to conclude that, during the winter, the water level increased due to the rain. For this reason, nutrient concentrations were low during the last period. Also, with the use of maps and remote sensing techniques, it is possible to determine the expected values around the station's location as future predictive readings that compensate for the difficulty of reaching these areas.

Fluorescence imprint alignment using additive-type inclination moiré fringes

It was studied whether additive-type fluorescence inclination moiré fringes were observed during imprint alignment by fluorescence microscopy using a pair of two periodical concave-line patterns with a long and short pitch of p1 and p2 prepared on silica mold and silicon substrate surfaces without any optically functional layer. A fluorescent liquid was sandwiched between the surfaces to fill into the concave lines and excited by exposure to visible light of 530–538 nm. In the detection wavelength range of 570–700 nm, additive-type fluorescence inclination moiré fringes generated from the place where bright concave lines with p1 on the substrate were overlaid with bright concave lines with p2 on the mold. The relationship of the mold-substrate angle deviation (θ) with the angle deviation (ψ) of an additive-type inclination moiré fringe was equal to the correlation of θ with the angle deviation (φ) of a multiplicative-type inclination moiré fringe.

Effect of the Surfactant Charge and Concentration on the Change in the Forces between Two Charged Surfaces in Surfactant Solutions by a Liquid Flow.

A combined atomic force microscope (AFM)-peristaltic pump system was used to determine the effect of a flow on the forces between two negatively charged surfaces (silica particle and silicon wafer) in aqueous solutions containing surfactants. The effect of the surfactant charge on the forces was determined by using an anionic surfactant (sodium dodecyl sulfate, SDS) and a cationic surfactant (dodecyltrimethylammonium bromide, DTAB) of the same chain length. The surfactant concentration effect was determined by using concentrations up to the critical micelle concentration. In the case of SDS, a flow reduced the range and magnitude of the repulsive forces. The force range reduction was explained by a shrinking of the diffuse layers, due to the deformation of the diffuse layer by the flow. The force magnitude reduction was explained by (1) the increased electrostatic screening due to the thinner diffuse layers and (2) an increased adsorption of specific ions, such as Na+, to the silica surfaces. In the case of DTAB, a concentration (8.0 mM) that gave an attractive force in the absence of a flow gave a repulsive force in the presence of a flow. Comparison of AFM images of a silicon wafer in DTAB measured in the absence and presence of a liquid flow showed that the number of DTAB patches adsorbed to the silicon wafer increased with a liquid flow. The change in the forces with a flow was therefore explained by this change in the DTAB adsorption to the negatively charged surfaces. As a liquid flow can change the charge of a surface, it may be possible to control the aggregation/dispersion of charged particles via the flow rate, if the appropriate surfactant type and concentration are used.

WITHDRAWN: Utilizing a single silica nanospring as an insulating support to characterize the electrical transport and morphology of nanocrystalline graphite

Abstract A graphitic carbon, referred to as Graphite from the University of Idaho Thermolyzed Asphalt Reaction (GUITAR), was coated on silica nanosprings and silicon substrates via the pyrolysis of commercial roofing tar at 800 °C in an inert atmosphere. Scanning electron microscopy and transmission electron microscopy images indicates that GUITAR is an agglomeration of carbon nanospheres formed by the accretion of graphitic flakes into a ∼100 nm layer. Raman spectroscopic analyses, in conjunction with scanning electron microscopy and transmission electron microscopy, indicate that GUITAR has a nanocrystalline structure consisting of ∼1–5 nm graphitic flakes interconnected by amorphous sp3 bonded carbon. The electrical resistivities of 11 single GUITAR-coated nanospring devices were measured over a temperature range of 10–80 °C. The average resistivity of all 11 devices at 20 °C was 4.3 ± 1.3 × 10−3 Ω m. The GUITAR coated nanospring devices exhibited an average negative temperature coefficient of resistivity at 20 °C of −0.0017 ± 0.00044 °C-1, which is consistent with the properties of nanocrystalline graphite.

Si cycling in transition zones: a study of Si isotopes and biogenic silica accumulation in the Chesapeake Bay through the Holocene

Si fluxes from the continents to the ocean are a key element of the global Si cycle. Due to the ability of coastal ecosystems to process and retain Si, the ‘coastal filter’ has the potential to alter Si fluxes at a global scale. Coastal zones are diverse systems, sensitive to local environmental changes, where Si cycling is currently poorly understood. Here, we present the first palaeoenvironmental study of estuarine biogenic silica (BSi) fluxes and silicon isotope ratios in diatoms (δ30Sidiatom) using hand-picked diatom frustules in two sediment cores (CBdist and CBprox) from the Chesapeake Bay covering the last 12000 and 8000 years, respectively. Constrained by the well-understood Holocene evolution of the Chesapeake Bay, we interpret variations in Si cycling in the context of local climate, vegetation and land use changes. δ30Sidiatom varies between + 0.8 and + 1.7‰ in both sediment cores. A Si mass balance for the Chesapeake Bay suggests much higher rates of Si retention (~ 90%) within the system than seen in other coastal systems. BSi fluxes for both sediment cores co-vary with periods of sea level rise (between 9500 and 7500 a BP) and enhanced erosion due to deforestation (between 250 and 50 a BP). However, differences in δ30Sidiatom and BSi flux between the sites emphasize the importance of the seawater/freshwater mixing ratios and locally variable Si inputs from the catchment. Further, we interpret variations in δ30Sidiatom and the increase in BSi fluxes observed since European settlement (~ 250 a BP) to reflect a growing human influence on the Si cycle in the Chesapeake Bay. Thereby, land use change, especially deforestation, in the catchment is likely the major mechanism.

Utilizing a Single Silica Nanospring as an Insulating Support to Characterize the Electrical Transport and Morphology of Nanocrystalline Graphite.

A graphitic carbon, referred to as graphite from the University of Idaho thermolyzed asphalt reaction (GUITAR), was coated in silica nanosprings and silicon substrates via the pyrolysis of commercial roofing tar at 800 °C in an inert atmosphere. Scanning electron microscopy and transmission electron microscopy images indicate that GUITAR is an agglomeration of carbon nanospheres formed by the accretion of graphitic flakes into a ~100 nm layer. Raman spectroscopic analyses, in conjunction with scanning electron microscopy and transmission electron microscopy, indicate that GUITAR has a nanocrystalline structure consisting of ~1–5 nm graphitic flakes interconnected by amorphous sp3 bonded carbon. The electrical resistivities of 11 single GUITAR-coated nanospring devices were measured over a temperature range of 10–80 °C. The average resistivity of all 11 devices at 20 °C was 4.3 ± 1.3 × 10−3 Ω m. The GUITAR coated nanospring devices exhibited an average negative temperature coefficient of resistivity at 20 °C of −0.0017 ± 0.00044 °C−1, which is consistent with the properties of nanocrystalline graphite.

Rekindling RNAi Therapy: Materials Design Requirements for In Vivo siRNA Delivery.

With the recent FDA approval of the first siRNA-derived therapeutic, RNA interference (RNAi)-mediated gene therapy is undergoing a transition from research to the clinical space. The primary obstacle to realization of RNAi therapy has been the delivery of oligonucleotide payloads. Therefore, the main aims is to identify and describe key design features needed for nanoscale vehicles to achieve effective delivery of siRNA-mediated gene silencing agents in vivo. The problem is broken into three elements: 1) protection of siRNA from degradation and clearance; 2) selective homing to target cell types; and 3) cytoplasmic release of the siRNA payload by escaping or bypassing endocytic uptake. The in vitro and in vivo gene silencing efficiency values that have been reported in publications over the past decade are quantitatively summarized by material type (lipid, polymer, metal, mesoporous silica, and porous silicon), and the overall trends in research publication and in clinical translation are discussed to reflect on the direction of the RNAi therapeutics field.

Study on the effect of modified and unmodified silica on the properties of natural rubber vulcanizates

AbstractIn the article, the effects of silica (silicon oxide) on some properties of natural rubber (NR) were studied. Silica used are unmodified (SiKBT) and modified with triethoxi silane propyl tetrasunfite (SiBT). It is shown SiBT increases vulcanization network density (VND), so it enhances strength and elastic properties of NR. In contrary, SiKBT decreases VND and reduces, but has almost no effect on strength of NR. Silica, both modified and unmodified, are assumed to improve network regularity of NR that change thermal degradation behavior of materials and keep the strength of NR‐SiKBT compound unchanged.

Synthesis and characterisation of VG nanosheets on silica aerogel by plasma‐enhanced chemical vapour deposition method

Vertical graphene (VG) nanosheets are directly grown on silica aerogel and silicon substrate (100) by plasma-enhanced chemical vapour deposition process in the presence of hydrogen as a reducing agent at atmospheric pressure at 800°C. The physiochemical properties of the nanohybrid were thoroughly characterised by Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The presence of full wave half maximum of D, G and D′ indicates VG nanowalls. The height (≅50 nm) of the VG nanowalls were confirmed by SEM and Raman spectroscopy but AFM reveals it as ≅ 15 nm. Surface and cross-sectional SEM show the uniform distribution of vertical growth of nanowalls and the AFM revealed surface morphology of VG nanowalls.

Corn-like stationary phase for solid phase microextraction prepared by electro-assisted deposition of sol-gel/silica nanoparticles composite

A novel solid phase microextraction (SPME) fiber was fabricated based on the electrophoretic and electrochemical deposition of silica nanoparticles and silicon alkoxides as sol-gel precursors. The surface of the Cu support was initially modified by a self-assembled monolayer (SAM) of (3-mercaptopropyl) trimethoxysilane (3MPTS). Then, the composite coating was electrodeposited on the modified substrate. The SEM images showed that porous and corn-like particles of composite were coated on the Cu wire substrate. The prepared composite was used as SPME fiber and applied to extract some halogenated benzenes from aqueous solution as model compounds. Parameters affecting the extraction efficiency such as extraction temperature, extraction time, and ionic strength were evaluated and optimized. Then, the extraction efficiency of the new fiber was evaluated by determining the limit of detection (LOD), linear dynamic range (LDR) and relative standard deviation (RSD). Using GC–MS determination of analytes it was found that LOD, LDR, and RSD of this method were between 0.1 and 0.6 μg L−1, 0.5–100 μg L−1 and less than 14.4%, respectively. The thermal stability of the fiber was investigated by thermogravimetric analysis, and finally, results show that each fiber is usable at 280 °C (3 min) for more than 80 times. Furthermore, the proposed fiber was successfully applied for quantification of halogenated benzenes in real water samples.

Function mechanism of Y2O3 additive in silicon powder nitridation

AbstractEffect of sole Y2O3 additive on the nitridation behavior of silicon powder was systematically studied using thermo gravimetry, differential thermal analysis, particle size analysis, X‐ray diffraction analysis, X‐ray photoelectron spectroscopy, scanning electron microscope and thermodynamic analysis in this paper. The thermo gravimetry results showed that Y2O3 additive can significantly decrease the initial nitriding temperature and increase the nitriding rate. This phenomenon can be attributed to the much lower reaction temperature of the silica film and Y2O3 additive than that of the silica film and silicon. In addition, Y2O3 additive has little effect on the nitridation of silicon powder at 1300°C. However, it can obviously enhance the nitridation of silicon powder and the formation of β‐Si3N4 at 1400°C, which is evidenced by the fact that the overall conversion increases from 58.1% to 100% and the fraction of β‐Si3N4 in generated Si3N4 increases from 7.9% to 68.2% with increasing the content of Y2O3 additive from 0 to 10 wt%.