Dr. Noushin Nasiri is a Postdoctoral Research Fellow at the University of Technology Sydney (UTS), the Institute for Biomedical Materials & Devices (IBMD). She has received her Masters of Engineering in Materials Engineering from the University of Tehran in Iran and then pursued her research at the Nanotechnology Research Laboratory of the Australian National University (ANU) where she received her PhD in Nanotechnology, in 2017.
Her research has been recognized with more than 20 peer-reviewed journal articles, and also several awards including the First Prize in the 2017 AMP Amplify Ignite Competition, the Runner-up Award for the 2016 Famelab Australia Grand Final and the People’s Choice Award for the 2015 ANU Grand Final 3MT. In addition, she presented her research on developing biosensors to detect disease through human breath at the TEDx Sydney Salon in April 2017.
2016 ANU Postgraduate Research Scholarship
2015 “Runner-up Award”, ANU Open Day 3MT
2015 “Runner-up Award”, ANU School of Engineering 3MT
2015 “People’s Choice Award”, ANU School of Engineering 3MT
2012 ANU PhD Scholarship (International)
2012 ANU HDR Merit Scholarship
- Point of care, disease detection via breath and saliva
- Fabrication and integration of optoelectronic devices such as photodetector, solar cells and gas sensors based on ultraporous nanostructured semiconductors.
- Optics and Photonics, Sensor Technology, Nanofabrication, Growth and self-assembly
Bo, R., Nasiri, N., Chen, H., Caputo, D., Fu, L. & Tricoli, A. 2017, 'Low-Voltage High-Performance UV Photodetectors: An Interplay between Grain Boundaries and Debye Length.', ACS applied materials & interfaces, vol. 9, no. 3, pp. 2606-2615.View/Download from: UTS OPUS or Publisher's site
Accurate detection of UV light by wearable low-power devices has many important applications including environmental monitoring, space to space communication, and defense. Here, we report the structural engineering of ultraporous ZnO nanoparticle networks for fabrication of very low-voltage high-performance UV photodetectors. A record high photo- to dark-current ratio of 3.3 105 and detectivity of 3.2 1012 Jones at an ultralow operation bias of 2 mV and low UV-light intensity of 86 Wcm-2 are achieved by controlling the interplay between grain boundaries and surface depletion depth of ZnO nanoscale semiconductors. An optimal window of structural properties is determined by varying the particle size of ultraporous nanoparticle networks from 10 to 42 nm. We find that small electron-depleted nanoparticles (40 nm) are necessary to minimize the dark-current; however, the rise in photocurrent is tampered with decreasing particle size due to the increasing density of grain boundaries. These findings reveal that nanoparticles with a size close to twice their Debye length are required for high photo- to dark-current ratio and detectivity, while further decreasing their size decreases the photodetector performance.
Nasiri, N., Bo, R., Fu, L. & Tricoli, A. 2017, 'Three-dimensional nano-heterojunction networks: a highly performing structure for fast visible-blind UV photodetectors.', Nanoscale, vol. 9, no. 5, pp. 2059-2067.View/Download from: Publisher's site
Visible-blind ultraviolet photodetectors are a promising emerging technology for the development of wide bandgap optoelectronic devices with greatly reduced power consumption and size requirements. A standing challenge is to improve the slow response time of these nanostructured devices. Here, we present a three-dimensional nanoscale heterojunction architecture for fast-responsive visible-blind UV photodetectors. The device layout consists of p-type NiO clusters densely packed on the surface of an ultraporous network of electron-depleted n-type ZnO nanoparticles. This 3D structure can detect very low UV light densities while operating with a near-zero power consumption of ca. 4 10-11 watts and a low bias of 0.2 mV. Most notably, heterojunction formation decreases the device rise and decay times by 26 and 20 times, respectively. These drastic enhancements in photoresponse dynamics are attributed to the stronger surface band bending and improved electron-hole separation of the nanoscale NiO/ZnO interface. These findings demonstrate a superior structural design and a simple, low-cost CMOS-compatible process for the engineering of high-performance wearable photodetectors.
Naz, M., Nasiri, N., Ikram, M., Nafees, M., Qureshi, M.Z., Ali, S. & Tricoli, A. 2017, 'Eco-friendly biosynthesis, anticancer drug loading and cytotoxic effect of capped Ag-nanoparticles against breast cancer', APPLIED NANOSCIENCE, vol. 7, no. 8, pp. 793-802.View/Download from: UTS OPUS or Publisher's site
Tricoli, A., Nasiri, N. & De, S. 2017, 'Wearable and Miniaturized Sensor Technologies for Personalized and Preventive Medicine', Advanced Functional Materials, vol. 27, no. 15.View/Download from: UTS OPUS or Publisher's site
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim The unprecedented medical achievements of the last century have dramatically improved our quality of life. Today, the high cost of many healthcare approaches challenges their long-term financial sustainability and translation to a global scale. The convergence of wearable electronics, miniaturized sensor technologies, and big data analysis provides novel opportunities to improve the quality of healthcare while decreasing costs by the very early stage detection and prevention of fatal and chronic diseases. Here, some exciting achievements, emerging technologies, and standing challenges for the development of non-invasive personalized and preventive medicine devices are discussed. The engineering of wire- and power-less ultra-thin sensors on wearable biocompatible materials that can be placed on the skin, pupil, and teeth is reviewed, focusing on common solutions and current limitations. The integration and development of sophisticated sensing nanomaterials are presented with respect to their performance, showing exemplary implementations for the detection of ultra-low concentrations of biomarkers in complex mixtures such as the human sweat and breath. This review is concluded by summarizing achievements and standing challenges with the aim to provide directions for future research in miniaturized medical sensor technologies.
Wong, W.S.Y., Liu, G., Nasiri, N., Hao, C., Wang, Z. & Tricoli, A. 2017, 'Omnidirectional Self-Assembly of Transparent Superoleophobic Nanotextures.', ACS nano, vol. 11, no. 1, pp. 587-596.View/Download from: UTS OPUS or Publisher's site
Engineering surface textures that are highly transparent and repel water, oil, and other low surface energy fluids can transform our interaction with wet environments. Despite extensive progress, current top-down methods are based on directional line-of-sight fabrication mechanisms that are limited by scale and cannot be applied to highly uneven, curved, and enclosed surfaces, while bottom-up techniques often suffer from poor optical transparency. Here, we present an approach that enables the rapid, omnidirectional synthesis of flexible and up to 99.97% transparent superhydrophobic and -oleophobic textures on many variable surface types. These features are obtained by the spontaneous formation of a multi re-entrant morphology during the controlled self-assembly of nanoparticle aerosols. We also develop a mathematical model to explain and control the self-assembly dynamics, providing important insights for the rational engineering of functional materials. We envision that our findings represent a significant advance in imparting superoleophobicity and superamphiphobicity to a so-far inapplicable family of materials and geometries for multifunctional applications.
Dibenedetto, A., Aresta, M., di Bitonto, L. & Pastore, C. 2016, 'Corrigendum: Organic Carbonates: Efficient Extraction Solvents for the Synthesis of HMF in Aqueous Media with Cerium Phosphates as Catalysts', ChemSusChem, vol. 9, no. 6, pp. 651-651.View/Download from: Publisher's site
Liu, G., Karuturi, S.K., Simonov, A.N., Fekete, M., Chen, H., Nasiri, N., Le, N.H., Reddy Narangari, P., Lysevych, M., Gengenbach, T.R., Lowe, A., Tan, H.H., Jagadish, C., Spiccia, L. & Tricoli, A. 2016, 'Robust Sub-Monolayers of Co3O4Nano-Islands: A Highly Transparent Morphology for Efficient Water Oxidation Catalysis', Advanced Energy Materials, vol. 6, no. 15.View/Download from: UTS OPUS or Publisher's site
© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim The scalable synthesis of highly transparent and robust sub-monolayers of Co 3 O 4 nano-islands, which efficiently catalyze water oxidation, is reported. Rapid aerosol deposition of Co 3 O 4 nanoparticles and thermally induced self-organization lead to an ultra-fine nano-island morphology with more than 94% light transmission at a wavelength of 500 nm. These transparent sub-monolayers demonstrate a remarkable mass-weighted water oxidation activity of 2070–2350 A g Co3O4 1 and per-metal turnover frequency of 0.38–0.62 s 1 at an overpotential of 400 mV in 1 m NaOH aqueous solution. This mixed valent cobalt oxide structure exhibits excellent long-term electrochemical and mechanical stability preserving the initial catalytic activity over more than 12 h of constant current electrolysis and 1000 consecutive voltammetric cycles. The potential of the Co 3 O 4 nano-islands for photoelectrochemical water splitting has been demonstrated by incorporation of co-catalysts in GaN nanowire photoanodes. The Co 3 O 4 -GaN photoanodes reveal significantly reduced onset overpotentials, improved photoresponse and photostability compared to the bare GaN ones. These findings provide a highly performing catalyst structure and a scalable synthesis method for the engineering of efficient photoanodes for integrated solar water-splitting cells.
Liu, G., Wong, W.S.Y., Nasiri, N. & Tricoli, A. 2016, 'Ultraporous superhydrophobic gas-permeable nano-layers by scalable solvent-free one-step self-assembly.', Nanoscale, vol. 8, no. 11, pp. 6085-6093.View/Download from: UTS OPUS or Publisher's site
Superhydrophobic materials with excellent humidity tolerance, high porosity and light transmittance are being investigated for numerous applications including moisture-sensitive catalysts and perovskite solar cells. Here, we report the one-step solvent-free synthesis of ultraporous superhydrophobic nano-layers by the on-the-fly functionalization of nanoparticle aerosols. Short exposure of surfaces to hot Mn3O4, ZnO and TiO2 aerosols results in ultraporous nanoparticle networks with repulsive dewetting state approaching ideal Cassie-Baxter superhydrophobicity. In addition to showcasing sliding angles of ca. 0° and very low contact angle hysteresis of 3° ± 2°, these optimal nano-layers have up to 98% porosity and pore size of several micrometres, a key feature to enable efficient penetration of gases to the substrate surface. The stability of this ultraporous superhydrophobic morphology is demonstrated by rapidly applying Moses effect-functionality to substrates that parts water up to 5 mm high. This scalable synthesis method offers a flexible and rapid approach for the production of numerous moisture-resistant devices including gas sensors, catalysts and perovskite solar cells.
Mayon, Y.O., Duong, T., Nasiri, N., White, T.P., Tricoli, A. & Catchpole, K.R. 2016, 'Flame-made ultra-porous TiO2 layers for perovskite solar cells.', Nanotechnology, vol. 27, no. 50, p. 505403.View/Download from: UTS OPUS or Publisher's site
We report methyl ammonium lead iodide (MAPbI3) solar cells with an ultra-porous TiO2 electron transport layer fabricated using sequential flame aerosol and atomic layer depositions of porous and compact TiO2 layers. Flame aerosol pyrolysis allows rapid deposition of nanostructured and ultra-porous TiO2 layers that could be easily scaled-up for high-throughput low-cost industrial solar cell production. An efficiency of 13.7% was achieved with a flame-made nanostructured and ultra-porous TiO2 electrode that was coated with a compact 2 nm TiO2 layer. This demonstrates that MAPbI3 solar cells with a flame-made porous TiO2 layer can have a comparable efficiency to that of the control MAPbI3 solar cell with the well-established spin-coated porous TiO2 layer. The combination of flame aerosol and atomic layer deposition provides precise control of the TiO2 porosity. Notably, the porosity of the as-deposited flame-made TiO2 layers was 97% which was then fine-tuned down to 87%, 56% and 35% by varying the thickness of the subsequent compact TiO2 coating step. The effects of the decrease in porosity on the device performance are discussed. It is also shown that MAPbI3 easily infiltrates into the flame-made porous TiO2 nanostructure thanks to their high porosity and large pore size.
Nasiri, N., Bo, R., Chen, H., White, T.P., Fu, L. & Tricoli, A. 2016, 'Structural Engineering of Nano-Grain Boundaries for Low-Voltage UV-Photodetectors with Gigantic Photo- to Dark-Current Ratios', Advanced Optical Materials, vol. 4, no. 11, pp. 1787-1795.View/Download from: UTS OPUS or Publisher's site
© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Ultraporous networks of ZnO nanoparticles (UNN) have recently been proposed as a highly performing morphology for portable ultraviolet light photodetectors. Here, it is shown that structural engineering of the nanoparticle grain boundaries can drastically enhance the performance of UNN photodetectors leading to gigantic photo to dark current ratios with operation voltages below 1 V. Ultraporous nanoparticle layers are fabricated by scalable low-temperature deposition of flame-made ZnO aerosols resulting in highly transparent layers with more than 95% visible light transmittance and 80% UV-light absorption. Optimal thermally induced necking of the ZnO nanoparticles increased the photo- to dark-current ratio, at a low light density of 86 W cm 2 , from 1.4 10 4 to 9.3 10 6 , the highest so far reported. This is attributed to the optimal interplay of surface depletion and carrier conduction resulting in the formation of an open-neck grain boundary morphology. These findings provide a robust set of guiding principles for the design and fabrication of nanoparticle-based optoelectronic devices.
Nasiri, N., Bo, R., Hung, T.F., Roy, V.A.L., Fu, L. & Tricoli, A. 2016, 'Tunable Band-Selective UV-Photodetectors by 3D Self-Assembly of Heterogeneous Nanoparticle Networks', Advanced Functional Materials, vol. 26, no. 40, pp. 7359-7366.View/Download from: UTS OPUS or Publisher's site
© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Accurate detection of ultraviolet radiation is critical to many technologies including wearable devices for skin cancer prevention, optical communication systems, and missile launch detection. Here, a nanoscale architecture is presented for band-selective UV-photodetectors, which features unique tunability and miniaturization potential. The device layout relies on the 3D integration of ultraporous layers of tailored nanoparticles. By tailoring the transmittance window between the indirect band gap of TiO 2 nanoparticles and the sharp edge of the direct band gap of ZnO, a band-selective photoresponse is achieved with tunable bandwidth to less than 30 nm and photo- to dark-current ratios of several millions at a light intensity of 86 W cm 2 and operation bias of 1 V. The potential of this integrated morphology is shown by fabrication of the first inherent UVA photodetector with selectivity against the edge of the UVB and visible light of nearly 60 times. This tunable architecture and nanofabrication approach are compatible with state-of-the micromachining technologies and provide a flexible solution for the engineering of wearable band-selective photodetectors.
Nasiri, N., Ceramidas, A., Mukherjee, S., Panneerselvan, A., Nisbet, D.R. & Tricoli, A. 2016, 'Ultra-Porous Nanoparticle Networks: A Biomimetic Coating Morphology for Enhanced Cellular Response and Infiltration.', Scientific reports, vol. 6, p. 24305.View/Download from: UTS OPUS or Publisher's site
Orthopedic treatments are amongst the most common cause of surgery and are responsible for a large share of global healthcare expenditures. Engineering materials that can hasten bone integration will improve the quality of life of millions of patients per year and reduce associated medical costs. Here, we present a novel hierarchical biomimetic coating that mimics the inorganic constituent of mammalian bones with the aim of improving osseointegration of metallic implants. We exploit the thermally-driven self-organization of metastable core-shell nanoparticles during their aerosol self-assembly to rapidly fabricate robust, ultra-porous nanoparticle networks (UNN) of crystalline hydroxyapatite (HAp). Comparative analysis of the response of osteoblast cells to the ultra-porous nanostructured HAp surfaces and to the spin coated HAp surfaces revealed superior osseointegrative properties of the UNN coatings with significant cell and filopodia infiltration. This flexible synthesis approach for the engineering of UNN HAp coatings on titanium implants provides a platform technology to study the bone-implant interface for improved osseointegration and osteoconduction.
Tricoli, A., Nasiri, N., Chen, H., Wallerand, A.S. & Righettoni, M. 2016, 'Ultra-rapid synthesis of highly porous and robust hierarchical ZnO films for dye sensitized solar cells', Solar Energy, vol. 136, pp. 553-559.View/Download from: UTS OPUS or Publisher's site
© 2016 Elsevier Ltd Dye sensitized solar cells are a promising third generation solar cell technology bearing considerable commercial potential. Here, we present the synthesis of robust, aerogel-like ZnO nanoparticle films with extremely high porosity. These film morphologies enable synthesis of stable cells with linearly increasing photocurrent up to a working-electrode thickness of 200 m. Optimized films led to more than 100% efficiency enhancement with respect to more dense film morphologies made by wet-deposition of the same ZnO nanoparticles. These results suggest that optimization of the semiconductor-electrolyte nano-interface by a hierarchical multi-scale morphology has the potential to minimize electron-holes recombination enabling efficient thick cells with substantially higher surface area for dye absorption.
Liu, G., Hall, J., Nasiri, N., Gengenbach, T., Spiccia, L., Cheah, M.H. & Tricoli, A. 2015, 'Scalable Synthesis of Efficient Water Oxidation Catalysts: Insights into the Activity of Flame-Made Manganese Oxide Nanocrystals.', ChemSusChem, vol. 8, no. 24, pp. 4162-4171.View/Download from: UTS OPUS or Publisher's site
Chemical energy storage by water splitting is a promising solution for the utilization of renewable energy in numerous currently impracticable needs, such as transportation and high temperature processing. Here, the synthesis of efficient ultra-fine Mn3O4 water oxidation catalysts with tunable specific surface area is demonstrated by a scalable one-step flame-synthesis process. The water oxidation performance of these flame-made structures is compared with pure Mn2O3 and Mn5O8, obtained by post-calcination of as-prepared Mn3O4 (115m(2) g(-1)), and commercial iso-structural polymorphs, probing the effect of the manganese oxidation state and synthetic route. The structural properties of the manganese oxide nanoparticles were investigated by XRD, FTIR, high-resolution TEM, and XPS. It is found that these flame-made nanostructures have substantially higher activity, reaching up to 350% higher surface-specific turnover frequency (0.07molO2 m(-2) s(-1)) than commercial nanocrystals (0.02molO2 m(-2) s(-1)), and production of up to 0.33mmolO2 molMn (-1) s(-1). Electrochemical characterization confirmed the high water oxidation activity of these catalysts with an initial current density of 10mAcm(-2) achieved with overpotentials between 0.35 and 0.50V in 1m NaOH electrolyte.
Nasiri, N., Elmøe, T.D., Liu, Y., Qin, Q.H. & Tricoli, A. 2015, 'Self-assembly dynamics and accumulation mechanisms of ultra-fine nanoparticles.', Nanoscale, vol. 7, no. 21, pp. 9859-9867.View/Download from: UTS OPUS or Publisher's site
The self-assembly of nanomaterials into three-dimensional hierarchical structures is a fundamental step impacting a large number of synthetic and natural processes. These range from the scalable fabrication of nano-devices such as batteries, sensors and third generation solar cells to the uptake and accumulation of particulate pollution in the lung alveoli. Here, we show that the Dynamic behavior of ultra-fine particles (UFP < 100 nm) diverges significantly from that of sub- and micro equivalents. For freely diffusing bodies, this leads to the formation of stochastically reproducible films that approach the morphology and density of ballistically deposited ones. A novel deposition mechanism and regime are proposed that successfully capture the full spectrum of size-dependent self-assembly dynamics. These findings are a significant step toward the engineering of scalable parallel nano-fabrication approaches, and the understanding of the interaction of unbound nanostructures with their surrounding.
Wong, W.S.Y., Nasiri, N., Liu, G., Rumsey-Hill, N., Craig, V.S.J., Nisbet, D.R. & Tricoli, A. 2015, 'Flexible Transparent Hierarchical Nanomesh for Rose Petal-Like Droplet Manipulation and Lossless Transfer', Advanced Materials Interfaces, vol. 2, no. 9.View/Download from: UTS OPUS or Publisher's site
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Precise manipulation of water is a key step in numerous natural and synthetic processes. Here, a new flexible and transparent hierarchical structure is determined that allows ultra-dexterous manipulation and lossless transfer of water droplets. A 3D nanomesh is fabricated in one step by scalable electrospinning of low-cost polystyrene solutions. Optimal structures are composed of a mesh of dense nanofiber layers vertically separated by isolated mesoporous microbeads. This results in a highly adhesive superhydrophobic wetting that perfectly mimics rose petal-like structures. Structural-functional correlations are obtained over all key process parameters enabling robust tailoring of the wetting properties from hydrophilic to lotus-like Cassie-Baxter and rose-like Cassie-impregnating states. A mechanistic model of the droplet adhesion and release dynamics is obtained alongside the first demonstration of a mechanically induced transfer of microdroplets between two superhydrophobic coatings. This low-temperature reaction-free material structure demonstrates a facile means to fabricate impenetrable residue-less rose petal-like surfaces with superhydrophobic contact angles of 152 ± 2°and effective adhesion strength of 113 ± 20 N. This is a significant step toward parallel, multistep droplet manipulation with applications ranging from flexible on-paper devices to microfluidics and portable/wearable biosensors.
Nasiri, N., Bo, R., Wang, F., Fu, L. & Tricoli, A. 2015, 'Ultraporous Electron-Depleted ZnO Nanoparticle Networks for Highly Sensitive Portable Visible-Blind UV Photodetectors.', Advanced Materials, vol. 27, no. 29, pp. 4336-4343.View/Download from: UTS OPUS or Publisher's site
A hierarchical nano- and microstructured morphology for visible-blind UV photo-detectors is developed, which provides record-high milliampere photocurrents, nanoampere dark currents, and excellent selectivity to ultralow UV light intensities. This is a significant step toward the integration of high-performance UV photodetectors in wearable devices.
Wong, W.S.Y., Nasiri, N., Rodriguez, A.L., Nisbet, D.R. & Tricoli, A. 2014, 'Hierarchical amorphous nanofibers for transparent inherently super-hydrophilic coatings', Journal of Materials Chemistry A, vol. 2, no. 37, pp. 15575-15581.View/Download from: UTS OPUS or Publisher's site
Ultra-high specific surface area, hierarchical TiO 2 nanofibers were synthesized by electrospinning and directly self-assembled into highly porous films for application as transparent super-hydrophilic coatings. The evolution of the coating key structural properties such as fiber morphology and composition was mapped from the as-prepared sol-gel up to a calcination temperature of 500 °C. Main fiber restructuring processes such as formation of amorphous Ti-O bonds, crystallization, polymer decomposition and the organic removal were correlated to the resulting optical and wetting performance. Conditions for low-temperature synthesis of hierarchical coatings made of amorphous, mesoporous TiO 2 nanofibers with very high specific surface area were determined. The wetting properties of these amorphous and crystalline TiO 2 nanofiber films were investigated with respect to the achievement of inherently super-hydrophilic surfaces not requiring UV-activation. The surface stability of these amorphous TiO 2 nanofibers was assessed against current state-of-the-art crystalline super-hydrophilic TiO 2 preserving excellent anti-fogging performance upon an extended period of time (72 h) in darkness. © the Partner Organisations 2014.
Emamy, M., Khodadadi, M., Honarbakhsh Raouf, A. & Nasiri, N. 2013, 'The influence of Ni addition and hot-extrusion on the microstructure and tensile properties of Al-15%Mg2Si composite', Materials and Design, vol. 46, pp. 381-390.View/Download from: UTS OPUS or Publisher's site
The effects of nickel addition and hot-extrusion on the microstructure and tensile properties of in situ Al-15%Mg 2 Si composite specimens have been investigated. Al-15%Mg 2 Si composite ingots were prepared by an in situ process and different amounts of nickel (0.1, 0.3, 0.5, 1.0, 3.0 and 5.0wt% Ni) were added to the remelted composite. Optical microscopy (OM) and scanning electron microscopy (SEM) indicated that Ni addition changes the morphology of both primary and eutectic Mg 2 Si phases and decreases the size of primary Mg 2 Si particles from 42m to 17m. Hot-extrusion was found to be powerful in breaking the eutectic network and changing the size and morphology of pseudo-eutectic Mg 2 Si phase. The results obtained from tensile testing revealed that both Ni addition and hot-extrusion process improve ultimate tensile strength (UTS) and elongation values. Fracture surface examinations revealed a transition from brittle fracture mode in as-cast composite to ductile fracture in hot-extruded composite after Ni addition. This can be attributed to the changes in size and morphology of primary and eutectic Mg 2 Si phases and also the formation of more and finer -Al phase. © 2012 Elsevier Ltd.
Nasiri, N., Emamy, M. & Malekan, A. 2012, 'Microstructural evolution and tensile properties of the in situ Al-15%Mg2Si composite with extra Si contents', Materials and Design, vol. 37, pp. 215-222.View/Download from: UTS OPUS or Publisher's site
In the present work, the effect of extra Si addition on the microstructure and tensile properties of Al-15%Mg 2 Si composite has been investigated. The Al-15%Mg 2 Si composite ingot was made by in situ process and different amounts of extra Si (0.5, 1, 1.5, 2, 5 and 7wt.% Si) were added to the remelted composite. Optical microscopy and scanning electron microscopy (SEM) indicated that the addition of extra Si up to 2wt.%, reduces the average Mg 2 Si particle size from 39m to 26m and increases the volume fraction of -Al phase from 6% to 22%. Addition of extra Si content up to 7wt.% leads to the formation of primary Mg 2 Si particles with larger size (38m). The results of tensile test revealed that the addition of extra Si improves ultimate tensile strength (UTS) and elongation values of the composite from 176MPa and 1.7% to 222MPa and 3.0% respectively. Fractographic analysis of specimens exposed a cellular nature for the fracture surface. On the cellular fracture surface, the features of both brittle and ductile fracture were present simultaneously. Raising the amount of extra Si up to 7% has increased the number and decreased the size of dimples. These microstructural findings led to a change in the mode of fracture from brittle to ductile and increased elongation values. © 2011 Elsevier Ltd.
Nasiri, N., Emamy, M., Malekan, A. & Norouzi, M.H. 2012, 'Microstructure and tensile properties of cast Al-15%Mg2Si composite: Effects of phosphorous addition and heat treatment', Materials Science and Engineering A, vol. 556, pp. 446-453.View/Download from: UTS OPUS or Publisher's site
The effects of solution heat treatment and phosphorous addition on the microstructure and tensile properties of in situ Al-15%Mg 2 Si composite specimens have been investigated. The Al-15%Mg 2 Si composite ingot was made by in-situ process and different amounts of phosphorous (0.1, 0.3, 0.5, 0.7 and 1wt% P) were added to the remelted composite. Then, the specimens were subjected to solutionizing at 500°C for holding time of 4h followed by quenching. Optical microscopy (OM) and scanning electron microscopy (SEM) indicated that phosphorous addition not only changes the morphology of primary Mg 2 Si particles from dendritic to a regular shape, but also it reduces Mg 2 Si particle size. Solutionizing led to the dissolution of the Mg 2 Si particles and changed their morphology to round shape. The results obtained from tensile testing revealed that both phosphorous addition and solution heat treatment improve ultimate tensile strength (UTS) and elongation (El.%) values. According to the results, the optimum tensile property was achieved by adding 0.5wt% P to the Al-Mg 2 Si composite after solution heat treatment. Fractographic analysis revealed a cellular nature for the fracture surface of the MMC. As a result of P addition the potential sites for stress concentration and crack initiation areas were reduced due to microstructural modification, while increase in the number of fine dimples rendered the nature of fracture from brittle to ductile and also improved tensile properties. © 2012 Elsevier B.V.
Nasiri, N., Emamy, M. & Bigdeli, M. 2011, 'The effect of lithium on the microstructure and morphology of Fe-rich intermetallic compounds in 360 cast alloy', Advanced Materials Research, vol. 264-265, pp. 1782-1787.View/Download from: UTS OPUS or Publisher's site
In this study, the effect of small additions of lithium on the microstructure and morphology of Fe-containing intermetallic compounds in A360 alloy has been investigated. Different Fe contents (1, 1.5 and 2%) were added into A360 alloy, and Li concentrations also varied from 0 to 0.5 wt. %. The image analysis results showed that, the maximum length of -Al5FeSi plate in Li-modified specimens is changed significantly in comparison with non-modified ones. It is evident that the maximum reduction in the average length of Fe containing platelets occurs in specimens with 2% Fe. Also, the lowest changes in the length of intermetallic phases -as Fe content decreases- occur in the 0.5 wt% Li. At higher Li concentrations, the presence of Al-Li-Si intermetallics in the microstructure can provide undesirable condition. This intermetallic can be so damaging in mechanical properties especially in coarse shapes. © (2011) Trans Tech Publications, Switzerland.
Nasiri, N., Tobias, D.E., Qin, Q. & Tricoli, A. 1970, 'Aerosol self-assembly of nanoparticle films: Growth dynamics and resulting 3D structure', Proceedings of SPIE - The International Society for Optical Engineering, International Conference on Smart Materials and Nanotechnology in Engineering, SPIE, Gold Coast, Australia.View/Download from: UTS OPUS or Publisher's site
In this study, aerosol deposition of nanoparticles on flat surfaces has been investigated by Langevin dynamics (LD) accounting for Brownian's diffusion and a fix translational velocity. The particles are assumed to drop one at a time and had a monodisperse size distribution. The detailed morphology of the nanoparticle films was investigated as a function of Pe number, the ratio between Brownian and translational displacement for different structural constrains. The porosity was reduced with increasing Pe number from the diffusion to ballistic deposition limit. It was found that the simulation constrains have a substantial impact on the resulting film structural properties. This was attributed to the multi-scale porosity of these aerosol-deposited films. Keyword: Deposition, Nanoparticle, Porosity, Aerosol, Self-Assembly, Nanoparticles, Sensors. © 2013 SPIE.