<p>Processing of nanostructured WC-Co and W-Co powders,modelling of Fe-Mn-Si alloy, swelling of Fe-Cu alloy, andmechanical properties and sintering of Fe-Mn-Si steels havebeen studied in the present thesis.</p><p>W-Co precursors made by chemical synthesis were used toproduce nanostructured WCCo and W-Co powders by calcination,reduction and carburization. The phase constituents in thecalcined powders depend on temperature and atmospheres. Cobaltcan accelerate the reduction rate of the W-Co precursors as acatalyst, and cobalt influences the formation of intermediatephases during the reduction of the precursors.</p><p>The ratio of carbon monoxide to carbon dioxide controlscarburization process, gives different intermediate phases andcarburization rates. There exist several intermediate phases: W₆Co₆C, W₃Co₃C, W₂C due to varying carbon monoxide content in thecarburization gases. Nanostructured WC-Co powders with aparticle size of 20-50 nm have been obtained.</p><p>The effect of silicon content on the particle sizedistribution of milled Fe-Mn-Si master alloy powders is muchmore significant than that of manganese content. A finer finalparticle size can be obtained in the alloy powders with highersilicon compositions. Long time milling results in theagglomeration of small particles. The grinding process can bedescribed using classic batch grinding equation based on thepopulation balance model. A swelling model for Fe-Cu alloyssintered at the temperatures above the melting point of copperhas been established based on the penetration mechanism. In themodel, the particle coordination number and heating rate wereused to express the porosity and the thickness of the diffusionlayers between iron and copper particles respectively.</p><p>The effects of sintering temperature and time on theproperties of sintered steels have been studied. Fe-Mn-Simaster alloys made by cast-milling, atomizing, and acombination of atomization and milling have been covered. Themilled, and atomizationmilled alloy steels showed goodmechanical properties with small dimensional change. Transientliquid phase of the Fe-Mn-Si alloys accelerates densification,and offer fast diffusion of alloying elements. The addition ofa small amount of Fe-Mn-Si master alloy to Astaloy 85Mo powdercan lead to high strength with zero dimensional change.</p><p><b>Key words:</b>Processing; Modelling; Nanostructured powder;WC-Co; W-Co; Calcination; Reduction; Carburization; Particlesize; Sintered steel; Fe-Cu alloy; Swelling; Fe-Mn-Si masteralloy; Mechanical properties; Sintering parameters.</p>

Made available in DSpace on 2016-06-02T19:10:00Z (GMT). No. of bitstreams: 1 1871.pdf: 8952094 bytes, checksum: 0efd2a0c46e79e4b2cfa975b94333f02 (MD5) Previous issue date: 2008-02-29 / Financiadora de Estudos e Projetos / The alloys of Fe-Mn-Al system have been rather studied in last few years indicating good potential for application, with the benefit of exhibiting 10 to 15% less density, coupled to good performance related to its mechanical properties and strength at room and cryogenic temperatures, being an alternative for replacing some alloys of the Fe-Cr-Ni system, in certain situations. However, the literature presents a very limited amount of information about the mechanical properties of these materials at high temperatures, as in the case of hot tensile and creep testing. The superplasticity phenomenon remains as an entirely unexplored issue for this kind of steel. This work was planned with the objective of undertaking for the first time a systematic study on the superplastic behavior of an austenitic steel of this system, with chemical composition Fe 24.5Mn 6.5Al 1.5Si 1.1C (weight %). The material was prepared by different termomechanical processing routes, so as to obtain sheets with thickness around 1 mm, having a fine grained equiaxial, dual phase austenite / ferrite structure, with grain size around 3 µm. The material was submitted to both tensile testing ( at constant crosshead speed ) and creep testing ( at constant load ), on a temperature range from 600 to 1000oC, and strain rates raging from 10-6 to 1 s-1. A set of tensile tests was carried out monotonically using separate specimens until rupture under different combinations of crosshead speed and temperature. In another set the specimens were subjected to a sequence of crosshead speed changes at the ultimate tensile stress level, at a certain temperature. In both case the parameter m (strain rate sensitivity exponent) could be determined. The creep experiments enabled obtaining parameters like n (the stress exponent), Qf (the apparent activation creep energy) and ó0 (the threshold stress). Values of åf (maximum elongation observed at rupture) could be also obtained from both the tensile test and creep tests. The results from both procedures, i.e. tensile and the creep testing, were compared together showing good agreement with each other. The largest values of åf (around 660 %) associated to the largest m values (around 0,54) were observed at 800°C, for strain rates in the range from 10-4 to 10-3 s-1 ( in the case of tensile testing) and applied stress in the range from 20 to 50 MPa ( in the case of creep testing). Tensile tests carried at constant strain rate and creep tests carried out at constant stress allowed even greater values of these parameters to be achieved, at the maximum strain rate sensitivity region. A tensile test performed at constant Ý = 2,47 x 10-4 s-1 produced a maximum elongation at rupture åf = 750% and a creep test with constant &#963; = 30 MPa a maximum elongation åf = 737 % (without rupture of the specimen). Measurements of activation energy from creep tests indicated that the Fe-Mn- Al alloy exhibits values around that of grain boundary self diffusion of Fe in Austenite, in agreement with which is expected from the superplastic flow process. The analysis of creep test results also revealed that the material presents a Threshold Stress (óo ) around 6 7 MPa from 700 to 800ºC, and óo . 30 MPa at 900ºC. In this way, all the data from the variation of strain rate with stress ( Norton diagram ) could be rationalized by a single stress exponent n = 2, which is typical of the grain boundary sliding mechanism. Metallographic observation by optical microscopy on specimens from both the tensile and creep tests indicated that the grain size structure remains equiaxial and essentially stable even after the great levels of deformation attained at the various temperatures, which confirms the superplastic behavior condition achieved in this work. / Os aços austeníticos do sistema Fe-Mn-Al, bastante estudados nos últimos anos, indicam bom potencial de aplicação devido a vantagens como densidade (cerca de 15% menor que a dos aços inoxidáveis tradicionais), e boas propriedades mecânicas em temperaturas ambiente e criogênica, apresentando-se, em alguns casos, como alternativa de substituição de certas ligas do sistema Fe-Cr-Ni. No entanto, a literatura apresenta muito pouca informação sobre suas propriedades mecânicas em altas temperaturas, como no caso de tração a quente e fluência, por exemplo. O fenômeno de escoamento superplástico, em especial, permanece inteiramente inexplorado neste tipo de aço. Este trabalho teve como principal objetivo caracterizar sistematicamente pela primeira vez o comportamento superplástico de um aço austenítico desse tipo, com composição Fe 24.5Mn 6.5Al 1.5Si 1.1C (% peso). O material foi preparado utilizando-se diferentes rotas de processamento termomecânico, para obtenção de chapas com espessura da ordem de 1 mm, com estrutura de grãos finos e equiaxiais, tendo duas fases: austenita / ferrita, com tamanho médio em torno de 3 µm. O material foi ensaiado tanto em máquinas de tração (com velocidades constante do travessão) como de fluência (a carga constante) numa faixa de temperatura de 600°C a 1000°C, envolvendo taxas de deformação variando de 10-6 a 1 s-1. Em um dos métodos de ensaios de tração, diferentes amostras foram ensaiadas até a ruptura em velocidades e temperaturas distintas. Numa outra modalidade do mesmo ensaio, as amostras foram submetidas a uma seqüência de saltos de velocidade de tração, ao atingir a carga máxima, em uma certa temperatura. Em ambos os casos, foi possível determinar o parâmetro m (expoente de sensibilidade à taxa de deformação). Os ensaios de fluência permitiram obter valores dos parâmetros n (expoente de tensão), Qf (energia de ativação aparente de fluência) e ó0 (tensão limiar). Com os ensaios que foram prolongados até a ruptura (tração a quente e fluência) determinou-se também valores de åf (alongamento máximo na ruptura). Os resultados tanto dos ensaios de tração como de fluência foram comparados entre si e apresentaram boa concordância em ambos os procedimentos. Os maiores valores de åf (da ordem de 660 %) associados aos maiores valores de m (da ordem de 0,54) foram observados a 800ºC, para taxas de deformação na faixa de 10-4 a 10-3 s-1 (no caso dos ensaios de tração) e tensões aplicadas entre 20 a 50 MPa ( no caso dos ensaios de fluência). Ensaios de tração a taxa de deformação constante e de fluência a tensão constante, nessa temperatura, permitiram obter valores ainda maiores desses parâmetros, na região de máxima sensiblidade à taxa de deformação. No caso de um ensaio de tração com Ý = 2,47 x 10-4 s-1 chegou-se a åf = 750% e no caso de fluência com &#963; = 30 MPa atingiu-se um valor de åf = 737 % (sem ruptura da amostra). Medidas de energia de ativação a partir dos ensaios de fluência indicaram que a liga Fe-Mn-Al apresenta valores próximos dos de autodifusão em contornos de grão do Fe na Austenita, concordando com o que se espera do processo de escoamento superplástico. A análise dos resultados de fluência indicou também que o material apresenta uma Tensão Limiar (óo) variando de 6 7 MPa nas temperaturas de 700 a 800ºC, e de . 30 MPa a 900ºC, podendo todos os dados de variação da Taxa de Deformação com a Tensão ( diagrama de Norton ) ser racionalizados por um único expoente de tensão n = 2, típico do mecanismo de escorregamento de contornos de grãos. Observações metalográficas por microscopia ótica das amostras ensaiadas tanto em tração como fluência indicaram que a estrutura granular permanece equiaxial e praticamente estável, mesmo após os grandes alongamentos atingidos em cada temperatura, caracterizando a condição superplástica conseguida neste trabalho para a liga Fe-Mn-Al.

We are living in a world of steel. Although there are a lot of other material in use, our most used material is steel. From building industry to transportation and even mother industries like mining, we use steel in different grades and amounts. There is always need for different grades of steel, and there is always interest in better properties and lower costs. Fe-Mn-Al-C steel group is one of the grades of steel is from the TWIP family. Beside its interesting mechanical properties, its corrosion resistance and cryogenic properties makes it very desirable to substitute more expensive current classes of the steel used in the industry. The automobile industry is also looking forward to implement this family of the steel in their products. This group of steel based on their chemical content can created a carbide ordered phase called κ which is one of the reasons of its interesting mechanical properties beside the TWIP properties. While κ may give more hardness due to precipitation hardening, it will make the steel brittle. Thus we need an understanding of the phase diagram of this group of the steels in order to choose our material and process accordingly. Phase diagrams are material engineers’ road maps for the processes and material choice as the initial steps, since we can predict the processes results and stable phases based on the equilibrium state from the diagrams. As the number of components gets more than three the phase diagram calculations and determination gets harder. For the ternary alloying systems we can only show sections of the phase diagrams as isothermal sections, or consider an element constant and depict the diagram as a “binary” system for the other two alloying elements at the other element concentration. In this work, we tried to experiment on the experimental data for equilibrium phases of Fe-Mn-Al-C alloying system based on the Equilibrated Alloys for alloys containing 20, 30 and 40 weight percent Manganese. The results were compared to the current database of the Thermo-Calc software for this family and we found some inconsistencies between the experimental data and the calculations which shows that the calculated results for this alloying system with its high Mn-content, is not reliable and that the thermodynamic descriptions must be adjusted. / PrecHiMn (RFSR-CT-2010-00018)

Le développement d’une troisième génération d’aciers Fe-Mn-Al-C à structure duplex, pour des teneurs en Mn et Al inférieures à 8 %mass, pourrait être une réponse prometteuse aux objectifs d’allègement de 20% des véhicules automobiles, tout en garantissant des propriétés de haute résistance mécanique et haute formabilité.Le choix des nuances et l’optimisation des conditions d’élaboration nécessitent de prévoir en particulier les compositions et proportions des phases existantes en fonction de la route métallurgique. Une base de données thermodynamiques fiable et précise est donc requise. Cependant les données de la littérature sur le système quaternaire Fe-Mn-Al-C, dans les domaines de composition envisagés, sont limitées.Ce mémoire est consacré à l’établissement des équilibres de phases ferrite-α, austénite-γ et carbure-κ (Fe,Mn)3AlC entre 700 et 1000°C par une approche couplée d’expériences ciblées et de modélisation thermodynamique. Pour appuyer l’évolution expérimentale des fractions de phases et des compositions, une modélisation cinétique (DICTRA) est proposée. La cinétique de formation de l’austénite en fonction de la composition de l’alliage et de la température de maintien dans le domaine intercritique a été caractérisée. Les phases en équilibre, caractérisées par DRX, MEB, microsonde, sont représentées sous forme de conodes α/γ, γ/κ, α/γ/κ, ce qui permet de définir les domaines de stabilité de l’austénite et du carbure κ. Ces données expérimentales sont utilisées pour affiner la description thermodynamique du système quaternaire mais il est nécessaire de réviser la modélisation du carbure κ. / A third generation of Fe-Mn-Al-C steels with a duplex structure, for Mn and Al contents less than 8%mass, could be a promising response to the 20% weight lightening of automotive vehicles, by keeping a high strength and a high formability.The knowledge of the corresponding quaternary phase diagram serves as a roadmap for the choice of compositions and the optimization of elaboration conditions. A reliable and precise thermodynamic database is therefore required. However, the literature data on the Fe-Mn-Al-C quaternary system in the targeted domains are limited.This study is devoted to the establishment of phase equilibria involving ferrite-α, austenite-γ and carbide-κ (Fe,Mn)3AlC between 700 and 1000°C by a coupled approach of experiments and thermodynamic modeling. A kinetic model (DICTRA) is proposed to support the experimental evolution of phase fraction and composition. The kinetics of austenite formation as a function of the alloy composition and of the maintaining temperature in the intercritical domain have been calculated. The phases in equilibrium, characterized by XRD, SEM, EPMA, are represented as α/γ, γ/κ, α/γ/κ tie-lines in order to specify the stability fields of γ and κ. These data are used to refine the thermodynamic description of the quaternary system but it is necessary to revise the modeling of κ carbide.

Ce travail est consacré à la conception, à la synthèse et à l’étude de catalyseurs d’oxydation à base de métaux 3d en association avec des ligands non-innocents. Tout d’abord, le développement de complexes dérivés de deux ligands rédox-actifs tétra-azotés originaux (motifs o-phénylènediamine, aniline et dipyrrine) a été étudié. Plusieurs espèces dans différents états d’oxydation ont été préparées. L’élucidation de leurs structures électroniques a été réalisée par des techniques complémentaires (diffraction des rayons X, électrochimie, spectroscopies UV-Vis-NIR, EPR et Mössbauer). Un complexe de fer biradicalaire basé sur le ligand bis(2-aminophényl)-o-phénylènediamine a été synthétisé. Parallèlement, une architecture innovante bis(2-aminophényl)dipyrrine a été développée. En réaction avec du nickel, du cuivre et du cobalt, elle a conduit à trois complexes isostructuraux présentant un caractère radicalaire anilinyle-dipyrrinyle jamais mis en évidence auparavant. La complexation de cette dipyrrine au manganèse a formé un singulier complexe dinucléaire radicalaire avec une valence mixte inhabituellement localisée sur le ligand.Dans un second temps, les complexes de fer, de cuivre et de manganèse ont été évalués dans des applications d’oxydation. L’étude de la réactivité du biradicalaire de fer a entraîné l’observation d’une espèce à haute valence en spectroscopie Mössbauer. D’autre part, le complexe de cuivre a montré une activité en oxydation d’un alcool. Enfin, une activité en catalyse d’oxygénation aérobie a été identifiée avec le complexe dinucléaire radicalaire de manganèse. / This work is devoted to the design, the synthesis and the study of oxidation catalysts, based on 3d metals and non-innocent ligands. First, the development of complexes derived from two unprecedented tetra-nitrogenated redox-active ligands (o-phenylenediamine, aniline and dipyrrin motifs) has been investigated. A number of species at various oxidation states has been prepared. The elucidation of their electronic structures was performed by complementary techniques (X-Ray diffraction, electrochemistry, UV-Vis-NIR, EPR and Mössbauer spectroscopy). A biradical iron complex based on the bis(2-aminophenyl)-o-phenylenediamine ligand was synthesized. In parallel, an innovative bis(2-aminophenyl)dipyrrin architecture was developed. Its reactions with nickel, copper and cobalt led to three isostructural complexes, showing an unprecedented anilinyl-dipyrrinyl radical character. The complexation of the dipyrrin to manganese afforded a unique dinuclear radical complex with a rare ligand-based mixed valence.In a second phase, iron, copper and manganese complexes were assessed in oxidation applications. The reactivity study of the biradical iron resulted in the observation of a high-valent species thanks to Mössbauer spectroscopy. On the other hand, the copper complex has shown an activity in the oxidation of an alcohol. Finally, a catalytic aerobic activity in oxygenation catalysis was identified with the dinuclear manganese radical complex.

Ce travail de thèse a pour but l'élaboration et la caractérisation microstructurale / magnétique de systèmes multicouches Fe/Mn présentant un couplage d'échange anisotrope. La caractérisation structurale a été effectuée par microscopie électronique en transmission, ce qui a permis d'identifier les structures α-Fe et α-Mn ainsi que l'évolution de la rugosité aux interfaces avec la température de dépôt. Les analyses en sonde atomique tomographique ont permis d'obtenir une analyse locale des interfaces. Les profils linéaires de concentration obtenus ont révélé une asymétrie des interfaces Fe/Mn et Mn/Fe avec la formation de mélange Fe-Mn à concentration modulée aux interfaces, ainsi qu'une augmentation de la largeur de l'interface Fe/Mn avec la température de dépôt. Les mesures de spectroscopie Mössbauer ont permis d'identifier l'environnement local des atomes de Fe. Les zones riches en Fe sont ferromagnétiques avec une distribution de champ hyperfin reflétant la composition modulée, et les zones riches en Mn sont antiferromagnétiques avec une température de Néel sensiblement proche de celle du α-Mn. La caractérisation magnétique a été effectuée dans un premier lieu par magnétométrie à SQUID, ce qui a permis de déterminer l'évolution de l'aimantation globale des échantillons, le champ de d'échange et le champ coercitif. Par ailleurs, les profils d'aimantation en profondeur ont été obtenus par réflectométrie de neutrons polarisés, ce qui a permis d'identifier deux types de couches de Fe, ainsi que l'influence de la température d'élaboration sur le champ coercitif.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this work the structural and magnetic properties of (Y,TR)CrO3+γ (TR = Dy, Gd, Nd e Pr e γ = 0 ou 1) and YFe1-xCrxO3 (0 ≤ x ≤ 1) samples were studied and synthesized by coprecipitation method. The analysis of X-ray diffraction (XRD) allied to the Rietveld refinement method confirmed the formation of all phases in the systems proposed. The results of X ray absorption near edge (XANES) at K edge of Cr and Fe in YFe1-xCrxO3 series indicate a system mixed valences of Cr2+/Cr3+ and Fe2+/Fe3+. For the family of compounds (Y,TR)CrO3+γ, XRD in situ as a function of temperature measurements were performed and the results show a phase transition (Y,TR)CrO4 with tetragonal structure and space group I41/amd to the phase of perovskite (Y,TR)CrO3 with orthorhombic structure and space group Pbnm. These results were also confirmed by XANES in situ as a function of temperature measured in K Cr edge, which show a change in the XANES profile and pre and post edge energy due to change Cr5+ oxidation state (Y,TRCrO4) to Cr3+ oxidation state (TR,YCrO3). These results also show that depending on the ion Y or TR, the phase transition temperature unchanged. The magnetization measurements as a function of magnetic field and temperature for the samples of YFe1-xCrxO3 (0,5 ≤ x ≤ 1) (0.5 ≤ x ≤ 1) have antiferromagnetic ordering accompanied by a weak ferromagnetism. These results were also observed a strong dependence of TN with the Fe concentration in the structure. The reverse magnetization phenomenon was observed for the YFe0,5Cr0,5O3 sample, and the results show that this phenomenon has a strong dependence on the applied field. The magnetization measurements as a function of magnetic field and temperature ferromagnetic ordering to (Y, Dy, Gd)CrO4 and antiferromagnetic for (Nd,Pr)CrO4 samples, where the magnetic transition temperature occurred between 6 to 22 K. As for the systems (Dy,Gd, Nd, Pr)CrO3 samples showed predominant antiferromagnetic ordering, usually with two TN1 and TN2 transitions. / Neste trabalho foram estudadas as propriedades estruturais e magnéticas das amostras (Y,TR)CrO3+γ (TR = Dy, Gd, Nd e Pr e γ = 0 ou 1) e YFe1-xCrxO3 (0 ≤ x ≤ 1) sintetizadas pelo método da coprecipitação. As análises de difração de raios X (DRX) aliadas ao método de refinamento Rietveld confirmaram a formação das fases principais em todos os sistemas propostos. Os resultados de absorção de raios X próximo à borda (XANES) obtidos na borda K do Cr e Fe para série YFe1-xCrxO3 indicam um sistema de valências mistas de Cr2+/Cr3+ e Fe2+/Fe3+. Para a família de compostos (TR,Y)CrO3+γ, as medidas de DRX in situ em função da temperatura mostram uma transição de fase de (Y,TR)CrO4 com estrutura tetragonal e grupo espacial I41/amd para a fase do tipo perovskita (Y,TR)CrO3 que possui estrutura ortorrômbica pertencente ao grupo espacial Pbnm. Estes resultados foram também confirmados através de medidas XANES in situ em função da temperatura na borda K do Cr, os quais apresentam uma mudança significativa no perfil XANES e na energia de pré e pós borda devido a mudança do estado de oxidação Cr5+ (TR,YCrO4) para o estado de oxidação Cr3+ (TR,YCrO3). Esses resultados também mostram que a depender do íon Y ou TR, as temperaturas de transição de fase sofrem alterações. As medidas de magnetização em função do campo magnético e da temperatura para as amostras da série YFe1-xCrxO3 (0,5 ≤ x ≤ 1) apresentam ordenamento antiferromagnético acompanhado de um ferromagnetismo fraco. Nesses resultados também foi observado uma forte dependência da TN com a concentração de Fe na estrutura. O fenômeno de magnetização reversa foi observado para a amostra YFe0,5Cr0,5O3, e os resultados mostram que este fenômeno tem forte dependência com o campo aplicado. As medidas de magnetização em função do campo magnético e da temperatura indicam um ordenamento ferromagnético para as amostras (Y,Dy,Gd)CrO4 e antiferromagnético para (Nd,Pr)CrO4, onde as temperatura de transição magnética ocorreram entre 6 e 22 K. Já para os sistemas (Dy,Gd,Nd,Pr)CrO3 as amostras apresentaram ordenamento antiferromagnético predominantes, geralmente com duas transições TN1 e TN2.

Demands for new, energy-efficient appliances have greatly increased in response to our growing need for a more environmentally friendly society. Magnetic refrigeration is a technique that utilizes the magnetocaloric effect, with possible energy savings of up to 30% compared to commercial gas compression refrigerators. A material appropriate for commercial magnetocaloric devices should be both cheap and non-toxic; it should also exhibit a first-order magnetic transitions close to room temperature. The magnetic properties of Fe2P-related materials can be relevant in this context, since their magnetic properties can be finely tuned through the substitution of Fe by Mn and P by Si, As, Ge or B to meet the general requirements for a magnetocaloric device. An in-depth study has therefore here been made of the structural and magnetic properties of the (Fe,Mn)2(P,Si)-system. The phase diagram of the FeMnP1-xSix-system has been carefully re-examined. It is found to contain two single-phase regions: an orthorhombic Co2P-type structure (x &lt; 0.15) and a hexagonal Fe2P-type structure (0.24 ≤ x &lt; 0.50). Selected compounds within the Fe2P-type region of the phase diagram have been shown to exhibit potential for use in magnetic refrigeration applications. Neutron powder diffraction has here been used to determine the magnetic structures of selected crystalline compositions within the FeMnP1-xSix-system to gain a better understanding of its magnetic properties. The Fe2P-type region is mainly ferromagnetic, but an incommensurate antiferromagnetic structure has also been identified close to the Co2P/Fe2P-type phase border for x ≈ 0.25. The so-called ''virgin effect'' in the Fe2P-type region of the FeMn(P,Si) phase diagram is found to be accompanied by an irreversible structural phase transition induced by magnetostriction. This new phase is found to be preserved during successive cooling-heating cycles. Furthermore, the magnetic properties of the substituted Fe2P-type structure changes significantly for metal:non-metal ratios away from 2:1. Such deviations could well explain the apparently conflicting structure-property relationships described in earlier literature for the FeMnP1-xSix-system.

Fours sets of PM10 samples were collected in three sites in SEQ from December 2002 to August 2004. Three of these sets of samples were collected by QLD EPA as a part of their regular air monitoring program at Woolloongabba, Rocklea and Eagle Farm. Half of the samples were used in this study for the analysis of water-soluble ions, which are Na+, K+, Mg2+, Ca2+, NH4 +, Cl-, NO3 -, SO4 2-, F-, Br-, NO2 -, PO4 -3 and the other half was retained by QLD EPA. The fourth set of samples was collected at Rocklea, specifically for this study. A quarter of the samples obtained from this set of samples were used to analyse water-soluble ions; a quarter of the sample was used to analyse Pb, Cu, Al, Fe, Mn and Zn; and the rests were used to analyse US EPA 16 priority PAHs. The water-soluble ions were extracted ultrasonically with water and the major watersoluble anions as well as NH4 + were analysed using IC. Na+, K+, Mg2+, Ca2+ Pb, Cu, Al, Fe, Mn and Zn were analysed using ICP-AES while PAHs were extracted by acetonitrile and analysed using HPLC. Of the analysed water-soluble ions, Cl-, NO3 -, SO4 2-, Na+, K+, Mg2+ and Ca2+ were high in concentration and determined in all the samples. F-, Br-, NO2 -, PO4 -3 and NH4 + ions were lower in concentration and determined only in some samples. Na+ and Cl- were high in all samples indicating the importance of a marine source. Principal Component Analysis (PCA) was used to examine the temporal variations of the water-soluble ions at the three sites. The results indicated that there was no major difference between the three sites. However, comparing the average concentrations of ions and Cl-/Na+ it was concluded that Woolloongabba had more marine influence than the other sites. Al, Fe and Zn were detected in all samples. Al and Fe were high in all samples indicating the significance of a source of crustal matter. Cu, Mn and Pb were in low concentrations and were determined only in some samples. The lower Pb concentrations observed in the study than in previous studies indicate that the phasing-out of leaded petrol had an appreciable impact on Pb levels in SEQ. This study reports for the first time, simultaneous data on the water-soluble, metal ion and PAH levels of PM10 aerosols in Brisbane, and provides information on the most likely sources of these chemical species. Such information can be used alongside those that already exist to formulate PM10 pollution reduction strategies for SEQ in order to protect the community from the adverse effects of PM pollution.

No description available.