Recycling Of Powder Research Articles

Recycling of steel slag powder in green ultra-high strength concrete (UHSC) mortar at various curing conditions

The large quantity of steel slag deposit has caused great environmental pressure. This study aims to recycle steel slag as binder in the production of green ultra-high strength concrete (UHSC) subjected to different curing regimes (i.e. standard and steam curing). The fresh behaviors, mechanical properties, microstructure and ecological value of the UHSC are explicitly assessed with the help of the Funk and Dinger particle packing model. The results show that the inclusion of steel slag powder (SSP) increases the workability (up to about 13%) and wet packing density of UHSC. The use of SSP results in a decrease of early compressive strength, because the SSP inhibits cement hydration at early stage. The steam curing can minimize this negative impact of SSP on the early compressive strength (>120 MPa). Besides, the increase of SSP dosage results in a reduction in the flexural strength for both early and later ages, but steam curing reduces the decline ratio. The high temperature curing not only promotes the hydration process of both cement and SSP, but also accelerates the pozzolanic reaction of silica fume, resulting in a lower porosity (4.78%) of UHSC with SSP. Finally, the ecological assessment shows that the recycling SSP as a replacement of cement in the UHSC system can reduce energy consumption and carbon emissions. Therefore, the results in this study indicate the feasibility of utilizing SSP in the fabrication of sustainable UHSC products with excellent performance.

Recycling of date kernel powder (DKP) in mass concrete for mitigating heat generation and risk of cracking at an early age

Mass concrete in many structural and non-structural applications is prone to early age cracking and chemo-damage from the exothermic hydration reactions of the cement binder. Date kernels are a waste product generated in large quantities in the date processing industry in the Middle East, North Africa and other countries worldwide. The use of calcined date kernel powder (DKP) as a mineral admixture in concrete to reduce the heat of hydration and temperature rise in mass concrete is a novel idea for which no prior research has been condcuted. A combined experimental and numerical investigation was conducted to assess the performance of DKP as a heat-reducing material in mass concrete. Concrete mixes with 10%, 20% and 30% DKP replacing cement and similar mixes with fly ash (FA) were investigated for evolution of mechanical and thermal properties and the adiabatic heat of hydration. 3D finite element models of mass concrete blocks 2mx2mx2m in size were validated using the data obtained from similar blocks in field instrumented with thermocouples. The 3D FE model was subsequently used to predict the heat of hydration, temperature rise and cracking index of a mass concrete block with 30% DKP powder. Experimental results showed a significant reduction in the heat of hydration in DKP concrete, with levels comparable to the FA concrete without a significant impact of strength properties. The DKP waste material has a strong potential for reducing heat of hydration in mass concrete structures, thereby promoting waste utilization, recycling and sustainability.

Pomegranate Peel Powder: In Vitro Efficacy and Application to Contaminated Liquid Foods

In this study the recycling of pomegranate peel powder (PPP) was proposed. In particular, the use of powder loaded in a silk fibroin polymeric matrix to create an active pad was tested. For the sake of comparison, the powder alone was also analysed. Both powder and active pad efficacy was assessed in two different food systems, soymilk (rich in proteins), preliminarily contaminated with Pseudomonas spp. and yeasts, and apple juice (rich in carbohydrates), preliminarily contaminated with Alyciclobacillus acidoterrestris. Three different concentrations of powder alone and powder in the pad were tested (5%, 7.5% and 10% w/v) in both types of beverages. To assess a possible dependence of the efficacy on the powder granulometry, different powder sizes were preliminarily analysed on Pseudomonas spp. and yeasts using an in vitro test. PPP was effective on both Pseudomonas spp. and yeasts. No significant differences appeared among the tested granulometries and therefore in the subsequent tests powder with an average diameter of 250 µm was used. Results recorded with soymilk and apple juice were different. When applied to the soymilk, the activity of PPP in the pad was less effective than that recorded when the powder was directly added to the beverage. With the two highest powder concentrations directly added to food, more than four log cycle reductions in Pseudomonas spp. and yeast cells were recorded, compared to soymilk without any powder. Compared to the control sample, all the soymilk samples either with PPP or with the active pad showed a delayed microbial and fungal growth. When applied to apple juice, both powder and pad were effective at completely inhibiting the proliferation of A. acidoterrestris (<102 CFU/g).

Плазменно-жидкостной рециклинг металлического порошка для 3D печати

The limits and prospects of plasma-liquid recycling of EOS StainlessSteel PH1 powder by processing products made by selective laser melting (SLM) on an Electro Optical Systems (EOS) 3D printer were studied. The current-voltage characteristics (CVC), types and forms of combustion of gas-discharge plasma in the process of processing products of additive manufacturing have been studied. Microphotographs of the powder were obtained by scanning electron microscopy, and the elemental and granulometric composition of the obtained powders were determined. It has been established that plasma-liquid recycling makes it possible to obtain metalic powders for the 3D printing in range from 10 to 120 microns by size.

Recycling of diamond-wire sawing silicon powder by direct current assisted directional solidification

As the unavoidable by-products in the production of solar cells, the recycling and reuse of diamond-wire sawing silicon powder (DWSSP) have always been a key issue in the solar energy industry. However, until now, there is no effective method to achieve effective recovery of high-purity silicon. In this work, a new method was proposed to achieve the recycling of DWSSP. Direct current, as an external means, was introduced into the recycling process of DWSSP, and its influence mechanism on impurity removal process was also discussed. By optimizing the local temperature gradient at the front of the Solid-Liquid interface, and the impurity diffusion behavior at the front of the interface was improved. After purification, the impurity content in the silicon ingot is reduced significantly. Among them, Al, as the main metal impurity element was reduced to less than 5ppmw (from 13580ppmw), and Ni (80.78ppmw), Fe (57.60ppmw), Ti (5.79ppmw), etc. decreased to less than 1ppmw. This work improved the purification efficiency of DWSSP, and put forward an optimized recycling method, which is expected to realize the direct reuse of DWSSP in the photovoltaic industry.

Recycling of high-volume waste glass powder in alkali-activated materials: An efflorescence mitigation strategy

The increasing environmental burden at landfills due to the disposal of waste glass (WG) has motivated the scientific community to find alternative routes for its utilization. One of these promising routes is to use WG as a precursor in alkali-activated materials (AAMs). However, conventional AAMs (in particular alkali-activated slags) set rapidly and suffer severe efflorescence that restricts their field applications. This study investigates the setting behavior, compressive strength, and efflorescence characteristics of alkali-activated binder prepared principally with ground granulated blast furnace slag (GGBS), and large volumes of waste glass powder (WGP) were used as replacements of GGBS systematically to improve the properties of resulting binders. A range of properties was analyzed, including setting time, compressive strength, efflorescence characteristics, and microstructure of the alkali-activated GGBS/WGP (AASG) samples. The experimental results revealed that incorporating WGP to replace GGBS in AASG pastes reduced the compressive strengths and prolonged the setting time because of the low reactivity of WGP. Although using WGP as a replacement for GGBS decreased the strength, the incorporation of 75% WGP in AASG reduced the severity of efflorescence effectively. This reduction can be related to the lower Na/Si, Ca/Si, and the higher Si/Al in C-(N)-A-S-H type gel phases.

High-value recycling of waste tire rubber powder by wet mixing method

Producing waste rubber into powder and adding it to rubber products as filler is one of the most direct and valuable methods to recover waste rubber. However, weak interface adhesion between waste rubber powder and rubber matrix severely damages the properties of rubber composites. To solve this problem, we propose a method of filling waterjet-produced rubber powder (WPRP) in natural rubber (NR) matrix via a wet mixing process. The characterizations of WPRP, the wet mixing mechanism participated by WPRP, and the properties of the wet-mixing rubber composites are carefully investigated. The surface of WPRP is irregular and contains some hydroxyl groups generated by the cavitation effect of waterjet, which endows the WPRP surface with certain hydrophilicity. The hydrophilic groups enable the stable suspension and uniform distribution of WPRP in latex. The active and irregular surface accelerates the flocculation during high-speed shear mixing, promotes the entanglement of NR molecular chains with WPRP, and forms a network between WPRP and NR matrix, which improves the dispersion of carbon black. When adding 5 parts per hundred rubber (phr) of WPRP, the tensile strength and elongation at break of the rubber composites are 27.8 MPa and 614.1%, respectively, which are even better than those of pure NR. When adding 10 phr of WPRP, the tensile strength and elongation at break of the rubber composite maintain 97.6% and 96.2% of that without WPRPs, respectively. Additionally, the addition of WPRP can reduce the rolling resistance of the rubber composites. This method will allow more waste rubbers to be incorporated into high-value rubber products, thereby relieving environmental pressure and realizing the recycling of rubber materials.

Advancements in the Additive Manufacturing of Magnesium and Aluminum Alloys through Laser-Based Approach.

Complex structures can now be manufactured easily utilizing AM technologies to meet the pre-requisite objectives such as reduced part numbers, greater functionality, and lightweight, among others. Polymers, metals, and ceramics are the few materials that can be used in AM technology, but metallic materials (Magnesium and Aluminum) are attracting more attention from the research and industrial point of view. Understanding the role processing parameters of laser-based additive manufacturing is critical to maximize the usage of material in forming the product geometry. LPBF (Laser powder-based fusion) method is regarded as a potent and effective additive manufacturing technique for creating intricate 3D forms/parts with high levels of precision and reproducibility together with acceptable metallurgical characteristics. While dealing with LBPF, some degree of porosity is acceptable because it is unavoidable; hot ripping and cracking must be avoided, though. The necessary manufacturing of pre-alloyed powder and ductility remains to be the primary concern while dealing with a laser-based additive manufacturing approach. The presence of the Al-Si eutectic phase in AlSi10Mg and AlSi12 alloy attributing to excellent castability and low shrinkage, attaining the most attention in the laser-based approach. Related studies with these alloys along with precipitation hardening and heat treatment processing were discussed. The Pure Mg, Mg-Al alloy, Mg-RE alloy, and Mg-Zn alloy along with the mechanical characteristics, electrochemical durability, and biocompatibility of Mg-based material have been elaborated in the work-study. The review article also summarizes the processing parameters of the additive manufacturing powder-based approach relating to different Mg-based alloys. For future aspects, the optimization of processing parameters, composition of the alloy, and quality of powder material used will significantly improve the ductility of additively manufactured Mg alloy by the LPBF approach. Other than that, the recycling of Mg-alloy powder hasn't been investigated yet. Meanwhile, the post-processing approach, including a homogeneous coating on the porous scaffolds, will mark the suitability in terms of future advancements in Mg and Al-based alloys.

Recycling of granite powder and waste marble produced from stone processing for the preparation of architectural glass–ceramic

• Glass-ceramic was prepared using granite powder and waste marble by melting-sintering method. • The addition of MgO changes the main crystalline phase of the glass–ceramic from wollastonite to augite. • The acid resistance of glass-ceramics is weakened with the increase of basic oxide content in the chemical composition. • The glass–ceramic with flexural strength of 146.95 MPa and Vickers hardness of 10.24 GPa can be achieved. A large amount of solid waste is generated during the stone processing, and a serious environmental issues has arisen from the accumulation of these wastes. In this work, granite powder and waste marble are used to prepare architectural glass–ceramic. The mechanical properties, microstructure, and acid resistance of glass-ceramics designed with different compositions were investigated. With the increase of waste marble content, the main crystalline phase of glass–ceramic changed from anorthite to wollastonite, and the flexural strength of glass–ceramic was also enhanced. When the mass ratio of granite powder to waste marble is 40:60, a CaO-Al 2 O 3 -SiO 2 (CAS) glass–ceramic with a flexural strength of 109.33 MPa and a Vickers hardness of 6.61 GPa is obtained. After the addition of MgO, the main crystalline phase of the glass–ceramic is augite. Under the addition of 5 wt% MgO, the flexural strength and Vickers hardness of CaO-MgO-Al 2 O 3 -SiO 2 (CMAS) glass–ceramic reached the maximum, which are 146.95 MPa and 10.24 GPa, respectively. The mechanical properties of these two types of glass-ceramics developed from granite powder and waste marble can meet the requirements of building materials. From the acid resistance test results, it was found that the higher the content of MgO and CaO in the chemical composition of glass–ceramic, the worse the acid resistance. Therefore, the basic oxide content should be carefully controlled in the composition design of glass–ceramic. This technology of converting granite powder and waste marble into value-added glass–ceramic provides a promising method for the utilization of solid waste from stone processing, which can greatly improve the sustainability of the stone industry.

The harnessing of the waste arising from Y-TZP dental ceramics manufactured by CAD/CAM to be used as alternative dental materials

A large amount of yttria-stabilized zirconia (Y-TZP) waste is produced during the manufacture of dental prostheses by the CAD/CAM milling process. This work investigated the recycling and processing of zirconia waste powder (ZWP), generated from the manufacture of dental prostheses (CAD/CAM milling process). The physical and mechanical characteristics of the bodies produced with ZWP were evaluated. The received ZWP was calcined at 500 °C and de-agglomerated with a roll jar mill under different experimental conditions. The grinding condition with a relation between grinding medium mass (GM) and ZWP mass of 13 and a milling time of 90 min presented the best results. This procedure produced ZWP with the smallest mean particle size (0.4 μm) and the lowest tetragonal-monoclinic transformation (16.9%). The water absorption, apparent porosity, bulk density, and mechanical properties were evaluated from ZWP non-deagglomerated and ZWP de-agglomerated after sintering at 1300 °C, 1400 °C, and 1500 °C. ZWP de-agglomerated samples reached bulk density, microhardness, and flexural strength values of 5.8 ± 0.1 g/cm3, 1523 ± 173 HV, and 342.8 ± 66.7 MPa, respectively. The achieved values of bulk density and microhardness were similar to those of commercial ZrO2 bodies processed under the same conditions, 6.0 ± 0.1 g/cm3 and 1412 ± 70 HV, respectively. But flexural strength of ZWP bodies was lower than that of commercial ZrO2, 680.5 ± 96.0 MPa. However, the achieved strength is higher than that observed for porcelain and glass-ceramic dental materials used for single-unit anterior or posterior prostheses (<200 MPa), which depicts the ZWP potential as an alternative low-cost and high-strength material in ceramic prostheses.

The Influence of Powder Reuse on the Properties of Laser Powder Bed‐Fused Stainless Steel 316L: A Review

There is a clear economic benefit for the recycling of metallic powder during additive manufacturing (AM). Laser powder bed fusion (L‐PBF) is one such AM process and research has found that the properties of the powder feedstock can change when the powder is reused through mechanisms such as spatter generation and alterations in chemistry. Such changes to powder properties can accumulate and may lead to significant differences in the mechanical properties of the final component. Often the changes to part properties are reasonably small; however, there is not currently enough understanding of the specific links between powder properties and the characteristics of the end component for the effects of powder recycling to be discounted. Herein, the typical lifecycle of stainless steel 316L powder in L‐PBF, the changes that occur to the powder feedstock, and the effects that this may have on the mechanical properties of components manufactured with recycled powder are reviewed.

Multiple recycling of nickel alloy powder for selective laser melting process: influence on properties of the powder and printed material

PurposeThe purpose of this study is the 16-fold recycling process effect of VZH159 nickel alloy powder on its features and characteristics of the printed material obtained by selective laser melting (SLM). Chemical composition, content of gas impurities, powder grading, pore volume fraction and surface morphology of powder particles, structure and properties of SLM material, surface roughness and deviations from specified geometry of the test samples were investigated.Design/methodology/approachThe experiment’s method procedure presumes the use of only recycled powder without adding any virgin powder at each build cycle. To avoid powder sloughing because of incomplete filling of the build space, a print area delimiter was used. For all manufactured samples, hot isostatic pressing was carried out in an ASEA Quintus-16 facility. Heat treatment was carried out in air furnaces. Structure investigations were carried out on a Leica DMIRM metallographic complex. Microstructure studies were carried out on a Verios 460 scanning electron microscope with X-ray microanalysis.FindingsWith the number of recycling stages, an increase in oxygen content is observed in the powder, which leads to an increment for oxides in the printed material. The 16-fold recycling does not have a significant effect on the features of the powder itself and the printed material if the build space is filled with manufacturing parts by no more than 20%.Originality/valueThe creep rupture strength of the SLM material, which appears to be a sensitive characteristic to the quality of the applied powder, does not change in the printed material after all stages of powder recycling as well.

Assessment of the thermal degradation kinetics of fresh green coconut husk (Cocos nucifera L.) powder and after methyl levulinate production

This study describes the recycling of green coconut husk powder (CHP) aimed at the sustainable production of methyl levulinate. The preliminary step involved thermogravimetric analysis of green (CHP) and residues after synthesis of methyl levulinate with the catalyst’s aluminum sulfate (CHP-AS) and titanium dioxide (CHP-TD), based on a degradation and determination of activation energy using the Ozawa-Flynn-Wall (OWF) method. Thermogravimetric analyses showed significant differences between the main constituents of CHP, CHP-AS and CHP-TD residues: hemicellulose (18.18, 9.78 and 12.17%), cellulose (44.65, 26.18 and 44.23%) and lignin (20.09, 19.89 and 19.58%), respectively. The methyl levulinate concentration obtained by the reaction between CHP and aluminum sulfate was 16.53 g.L-1, due to the participation of hemicellulose and cellulose. The results showed that the activation energies calculated using the OFW method were 142 kJ.mol-1 (CHP), 125 kJ.mol-1 (CHP-AS) and 180 kJ.mol-1 (CHP-TD).

Recycling of waste glass powder and tyre fiber in the development of eco-efficient concrete for high-performance structural application

Concrete suffers from several drawbacks due to the pollution associated with cement production, low tensile strength and low strain capacity that result in low resistance to cracks. Several attempts have been made to utilize waste materials for economical, sustainable construction and to improve concrete characteristics. This paper aims to investigate the effect of waste glass powder (WGP) as a partial replacement of cement and waste tyre fibre (WTF) as fibre reinforcement in the production of high performance concrete (HPC). ACI 211.1 was used to design a grade 50 HPC. At the first stage, WGP was introduced at a replacement level of 0 to 25 at a 5% interval by weight of OPC increment. Compressive strength at 3, 7, 28, 56, and 90 days of curing and slump flow was investigated, as well as establishing the optimum WGP content. WTF was then added to the optimal WGP-HPC in varying percentage addition of 0 to 2% at an increase of 0.4% by weight in the second stage. The compressive, splitting tensile, and flexural strengths at 3, 7, 28, 56, and 90 days were investigated. Slump flow was also investigated. It was discovered that the WGP is a suitable material for use as a pozzolana as it satisfied the minimum requirement given in ASTM C618. The compressive strength of HPC increased up to a 10% OPC replacement level by WGP before it starts declining. This signifies that the highest compressive strength was obtained at 10% WGP replacement level. It was also shown that adding the WTF decrease the slump flow and enhanced the compressive, splitting tensile and flexural strengths of WGP-HPC up to 1.2% and then dropped. Overall, an optimal HPC mix with 10% OPC replacement by GWP and 1.2% WTF addition outperforms all other mixes.

Experimental investigation on recycling of waste pharmaceutical blister powder as partial replacement of fine aggregate in concrete

A novel and sustainable solution to recycle the pharmaceutical blister (PB), a medical waste, by replacing them with fine aggregates in the concrete has been presented here. Recycling of waste PB is often difficult and can demand high energy consumption. In this study, the waste PB were grinded and used as replacement of fine aggregate (sand) at substitution levels of 5%, 10%, 15%, 20%, 25% and 30% by weight of sand per cubic meter of concrete. The compressive, flexural, and tensile strength as well as the water absorption of concrete mixes was investigated. Although results report a loss of compressive, flexural, and tensile strength compared to standard mix, the target design strength is achieved in all the mixes. The water absorption criterion is also met as per the codal provisions. Thus, the outcomes of the study encourage the proposed method of recycling the waste PB in concrete.

Graphitic carbon nitride based immobilized and non-immobilized floating photocatalysts for environmental remediation

In solar photocatalysis, light utilization and recycling of powder from reaction solution are the main obstructions that hinder the photocatalytic efficacy of any photocatalyst. In this respect, a floatable system is effective for efficient solar photocatalysis by light utilization. Due to the maximum solar light absorption property, floating nanocomposite photocatalyst is an appealing substitute for effective wastewater treatment. Floating photocatalysts are a non-oxygenated and non-stirred solution that is a good light harvester, stable, non-toxic, biodegradable, naturally abundant in nature. They also have low density, a simple preparation process, no need to stir, and high porosity. Due to these characteristics, floating photocatalysts are widely favored and ideal candidates for practical environmental remediation. Several researchers have come up with new and innovative ways for immobilizing capable photocatalyst on a floatable substrate to produce floating nanocomposite photocatalytic material. In recent decades, g–C3N4–based floating photocatalysts have gained a lot of attention as g-C3N4 is a visible light active photocatalyst with unique and exceptional properties. It also has good photocatalytic activity in waste water treatment and environmental remediation. Many previous reports have studied the logical design and manufacturing method for heterojunction floating photocatalysts and immobilized floating photocatalysts. Based on those studies, we have focused on the g-C3N4 based immobilized and non-immobilized floating photocatalysts for pollutant degradation. We have also categorized immobilized floating photocatalyst based on several lightweight substrates such as expanded perlite and glass microbead. In addition, future challenges have been discussed to maximize solar light absorption and to improve the efficiency of broadband response floating photocatalysts. Floating photocatalysis is an advanced technique in energy conversion and environmental remediation thus requires special consideration.

Closed-loop recycling of C&D waste: Mechanical properties of concrete with the repeatedly recycled C&D powder as partial cement replacement

Studies have been conducted on the repeated recycling of recycled coarse aggregates and recycled fine aggregates obtained from concrete waste, but no research has been conducted on the repeated recycling of recycled powder as a partial replacement for cement, which is pointed out as a major source of CO2 in the concrete industry. This paper investigates the closed-loop recycling potential of construction wastes by evaluating the effects of repeated use of concrete powder generated in the production of recycled aggregates on the selected fresh and hardened mechanical properties of concrete. Through a series of concrete making and crushing, once-, twice-, three times-recycled concrete powder of less than 150 μm was collected and used as a partial replacement for cement in concrete matrices at replacement levels of 10%, 20% and 30%. According to the experiment results, the replacement ratio and the number of recycling of concrete powder are parameters that affect the properties of concrete, and in particular, the replacement ratio is more affected than the number of recycling. The strength of concrete containing 10–20% concrete powder surpassed the target strength by up to 21% over three times of recycling, and the cost and environmental benefits increase in proportion to the number of concrete powder recycling. This study can contribute to the valorization of construction waste by providing a new initiative for multi-recycling of concrete powder and a closed-loop recycling system for construction waste.

Recycling of Granite Powder and Waste Marble Produced from Stone Processing for the Preparation of Architectural Glass-Ceramic

Recycling of Granite Powder and Waste Marble Produced from Stone Processing for the Preparation of Architectural Glass-Ceramic

Recycling of waste glass powder as paste replacement in green UHPFRC

Featured by a high cement content and a large consumption of quartz sand, ultra-high performance fiber reinforced concrete (UHPFRC) encounters hindrance in the pursuit of carbon neutralization and extensive application. Recycling materials (e.g., waste glass) may lower the performance of UHPFRC when used as cement/aggregate substitution. To conquer this problem, an innovative paste replacement method, i.e., adding waste glass powder (WGP) to substitute an equal volume of paste without altering the paste composition, was employed. An optimum amount of WGP was revealed for remarkably enhancing the workability, compressive strength, bending strength and microstructure of UHPFRC. Meanwhile, cement content was reduced by 18.8% to 365 kg/m3, whilst the strength was remarkably increased to exceed 150 MPa. To explore the mechanism, the wet packing density and slurry film thickness (SFT) of the paste were determined, whereby empirical models were established based on SFT and fiber factor (FF) for workability. Lastly, certain synergistic effects between the combined use of WGP and steel fibers on the properties of green (low carbon) UHPFRC were identified.

Recycling of the Diamond-wire Saw Powder by Ni-catalyzed Nitridation to Prepare Si3N4

In this paper, the acceleration effect of nickel (Ni) on the direct nitridation process of the diamond-wire saw powder (DWSP) was investigated. The DWSP doped with Ni additives were nitrided at different temperatures. To study the mechanism of accelerated nitridation, the thermodynamics of Si-O-N-Ni and nitridation processes were analyzed by FactSage 7.2 and single-crystal silicon blocks were also nitrided instead of the DWSP. The results revealed that Ni decreased the nitridation temperature at which the DWSP began to gain significant weight and exhibited an excellent accelerating effect on the nitridation of the DWSP. At 1300°C the DWSP containing 2.0 wt% Ni additives had been completely nitrided within 2 h, whereas the DWSP without Ni additives had not been nitrided yet. Based on the equivalent substitution experiment, it could be concluded that the presence of Ni additives accelerated the nitridation and promoted the formation of the α-Si3N4 nanorods through facilitating the generation of the SiO(g) and destructing the silica film on the surface of silicon at lower temperature. Meanwhile, Ni additives also played an important part in the growth of α-Si3N4 nanorods by forming liquid Ni-Si alloy in the product.