Mechanical treatment

cheatgrass invasion erosion Great Basin hydrologic recovery infiltration juniper mastication mechanical treatments pinyon rainfall simulation rangeland runoff sagebrush restoration soil loss tree cutting tree shredding woodland encroachment woodland expansion Rangeland Ecology & Management 72 (2019) 47-68 ☆ This paper is Contribution 125 of the Sagebrush Steppe Treatment Evaluation Project (SageSTEP, www.sagestep.org), funded by the US Joint Fire Science Program, Bureau of Land Man- agement, and National Interagency Fire Center. The USDA is an equal opportunity provider and employer. Mention of a proprietary product does not constitute endorsement by the USDA and does not imply its approval to the exclusion of the other products that may also be suitable.

In the last years, researches regarding the manufacture of polyamide parts using selective laser sintering process have developed increasingly more because of the advantages this materials offer. This paper was focused on a comparative study about the mechanical proprieties and surface roughness of parts manufactured by Selective Laser Sintering (SLS) from PA2200 powder. Tested parts were achieved on DTM Sinterstation 2000 Machine and EOS Formiga P 100 Machine. The results obtained lead to the conclusion that the mechanical proprieties obtained for the test parts made at 7,5W laser power on DTM Sinterstation 2000 Machine, are close to the results obtained for the test parts made at 30W on EOS Formiga P 100 Machine.

La densification par diffusion à l'état solide est l'une des étapes les plus importantes du Moulage par Injection de Poudres (MIP). Un modèle de comportement de type viscoplastique est formulé pour représenter la densification des poudres métalliques. Les paramètres du modèle sont identifiés grâce à méthode inverse par comparaison entre les résultats expérimentaux et des résultats issus de simulations numériques. Le modèle physique ainsi identifié, ainsi que la procédure de simulation par éléments finis sont ensuite utilisés pour la simulation 3D de micro-composants obtenus par MIP, afin de quantifier les géométries et propriétés physiques.

Dans cette etude, nous presentons une approche nouvelle pour comprendre les mecanismes locaux de deformation.Les champs cinematiques obtenus a partir d’une grille nanoparticules d’or sont combines aux mesures cristallographiques de la region de la grille. Les deformations dans les grains et aux joints de grains et l’apparition des glissements et leurs evolutions sont suivies. Ces resultats locaux sont compares au comportement macroscopique fourni lors d’un essai de traction.

This paper attempts to improve the physical and mechanical properties of selective laser sintered polyamide PA2200 components through a vibratory surface finishing process by inducing severe plastic deformation at the outer surface layers. The industrial target of additive manufacturing components is to obtain structures having surface roughness, hardness, and other mechanical properties equivalent to or better than those produced conventionally. Compared to the as-built SLS PA2200 samples, vibratory surface finishing treated specimens exhibited a smooth surface microstructure and more favorable roughness, hardness, and tensile strength. Also, the duration of the vibratory surface finishing process showed a further improvement in the surface roughness and hardness of the SLS samples. Compared to the as-built state, the roughness and hardness of the surface-treated samples improved by almost 90% and 15%, respectively. Consequently, microstructural analysis indicates that lower surfac...

Les réponses mécanique et métallurgique de deux aciers faiblement alliés à l'introduction de carbone et d'azote ont été étudiées. Pour cela, des traitements de carbonitruration, de cémentation et de nitruration austénitique à pression atmosphérique ont été réalisés à une température de 1173 K en employant des atmosphères à base de CO + H2 et/ou NH3. Le logiciel Thermo-Calc [AND02] a permis d'estimer la quantité d'azote en solution solide dans l'austénite juste avant la trempe. L'azote en solution est considéré comme complétant le carbone dans l'établissement de la dureté après trempe. Les résultats montrent un bon accord avec le modèle de Norstrom [NOR76] qui prédit une relation linéaire entre la racine carrée de la fraction atomique des interstitiels et la micro-dureté Vickers mesurée. Après revenu, la nitruration austénitique seule réussit à établir en surface un niveau de dureté équivalent à celui d'un état trempé. Cela est attribué à une précipitation secondaire au-dessus d'une certaine température critique située entre 453 K et 573 K.

Using molecular dynamics simulations, we investigate the effect of uniaxial elastostatic compression on the potential energy, structural relaxation, and mechanical properties of binary glasses. We consider the three-dimensional Kob-Andersen binary mixture, which was initially cooled from the liquid state to the glass phase with a slow rate at zero pressure. The glass was then loaded with a static stress at the annealing temperature during extended time intervals. It is found that the static stress below the yielding point induces large-scale plastic deformation and significant rejuvenation when the annealing temperature is smaller than a fraction of the glass transition temperature. By contrast, aging effects become dominant at sufficiently small values of the static stress and higher annealing temperatures. The mechanical tests after the elastostatic compression have shown that both the elastic modulus and the yield stress decrease in rejuvenated samples, while the opposite trend was observed for relaxed glasses. These results might be useful for the thermomechanical processing of metallic glasses with optimized mechanical properties.

Dans ce travail, une caractérisation par diffraction des rayons X a été réalisée sur des échantillons d’acier inoxydable duplex 2205 afin de suivre la précipitation de la phase σ. Pour cela, une analyse métallographique (microscopie optique) a été réalisée et une caractérisation par diffraction des rayons X a été effectuée sur les échantillons en utilisant le logiciel MAUD (Materials Analysis Using Diffraction).

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Fabriqués industriellement depuis seulement une trentaine d'années, les aciers inoxydables austéno-ferritiques, dits duplex, sont encore peu connus. Leur comportement en fatigue plastique a fait l'objet de quelques études portant sur les sollicitations uniaxiales mais d'aucune sur les sollicitations multiaxiales. Or seule une connaissance approfondie des phénomènes influant sur son comportement permet de simuler et de prédire correctement le comportement d'un matériau dans une structure. Ce travail a pour but l'étude et la modélisation du comportement d'un acier inoxydable duplex sous chargement biaxial cyclique. Une démarche en trois étapes a été adoptée. Une première campagne d'essais de traction-torsion cycliques sur éprouvettes tubulaires a été menée. Nous avons étudié l'équivalence des directions de chargement, puis nous avons porté notre attention sur l'influence du trajet et de l'histoire du chargement. Les résultats ont montré que l'acier inoxydable duplex présente un sur-écrouissage sous sollicitations non-proportionnelles, et que son comportement dépend des sollicitations effectuées auparavant. Ensuite, afin d'interpréter les résultats obtenus lors de cette première campagne d'essais, la surface de plasticité a été mesurée plusieurs fois par cycle pendant le même type d'essai cyclique. Un très faible offset de déformation plastique (2 10-5) a été utilisé afin de ne pas perturber la surface à mesurer. Les évolutions des variables d'écrouissage isotrope et cinématique en ont été déduites. Enfin, trois modèles phénoménologiques de comportement ont été identifiés sur la base expérimentale. Nous nous sommes attachés à la simulation des niveaux de contrainte stabilisée ainsi qu'à la représentation du comportement de durcissement/adoucissement cyclique. La comparaison des résultats expérimentaux et numériques nous a permis de tester la validité des modèles identifiés. Mots clés : acier inoxydable austéno-ferritique, plasticité cyclique, essais multiaxiaux, surface de plasticité, loi de comportement. CYCLIC PLASTICITY OF AN AUSTENITIC-FERRITIC STAINLESS STEEL UNDER BIAXIAL NONPROPORTIONAL LOADING Austenitic-ferritic stainless steels are supplied since about 30 years only, so they are yet not well-known. Their behaviour in cyclic plasticity was studied under uniaxial loading but not under multiaxial loading, whereas only a thorough knowledge of the phenomena influencing the mechanical behaviour of a material enables to simulate and predict accurately its behaviour in a structure. This work aims to study and model the behaviour of a duplex stainless steel under cyclic biaxial loading. A three step method was adopted. A set of tension-torsion tests on tubular specimen was first defined. We studied the equivalence between loading directions, and then the influence of loading path and loading history on the stress response of the material. Results showed that duplex stainless steel shows an extrahardening under nonproportional loading and that its behaviour depends on previous loading. Then, in order to analyse the results obtained during this first experimental stage, the yield surface was measured at different times during cyclic loading of the same kind. A very small plastic strain offset (2 10-5) was used in order not to disturb the yield surface measured. The alteration of isotropic and kinematic hardening variables were deduced from these measures. Finally, three phenomenological constitutive laws were identified with the experimental set. We focused our interest on the simulation of stabilized stress levels and on the simulation of the cyclic hardening/softening behaviour. The comparison between experimental and numerical results enabled the testing of the relevance of these models.

Les propriétés mécaniques des films minces sont généralement déterminées par nanoindentation pour éviter l’influence du substrat. En effet, nous savons que le substrat influence cette mesure dès lors que l’indenteur pénètre à plus de 10 % de l’épaisseur du film pour la dureté, ce chiffre pouvant être ramené à 1 % pour le module d’élasticité. Pour des films extrêmement minces pour lesquels la mesure directe des propriétés ne serait pas possible, l’application de modèles pour séparer la contribution du substrat de la mesure est alors nécessaire. Dans ce travail, la dureté et le module d’élasticité d’un film de nitrure d’aluminium de 250 nm d’épaisseur déposé par Magnetron Sputtering ont été déterminées par nanoindentation. Pour réduire l’influence de l’incertitude de l’épaisseur du film sur la détermination des propriétés mécaniques, nous proposons de masquer cette épaisseur dans les termes de lissage de plusieurs modèles et d’étudier leurs convergences. Concernant le module d’élastic...

The effects on montmorillonite (Mt) and on sepiolite (Sep) of mechanical (60 and 180 s grinding time) and further thermal treatments (TT) at 500°C during 24 h, for removing diuron from aqueous solutions were evaluated. The adsorbents and complexes formed were characterised. The specific surface area (SSA), SEM, XRD and zeta potential of the clay mineral samples were determined. The SSA values showed an increase of 50% for ground Mt and a slight decrease for ground Sep. TT reduced SSA by 50% for the Sep samples, but similar values remained for the Mt samples. Both minerals showed a decrease in crystallinity with increasing grinding time and TT. The zeta potential showed an increased of the negative surface charge for the Mt ground samples, but no changes were noticed for the Sep ground samples. The Mt-TT samples showed a slight decrease whilst the Sep samples showed an increase of the negative surface charge in comparison to those without thermal treatment. The adsorption of diuron on Mt was lower than on Sep, and it decreased slightly after 60 and/or 180 s of grinding, despite the larger SSA values. This differences on the adsorption extent were probably due to the increased micropore surface. In contrast, thermal activation caused significantly increased adsorption, especially for the 180-s ground sample that was inversely correlated with the micropore surface, indicating that diuron was not adsorbed in micropores. Diuron adsorption on Sep was higher than on Mt due to its higher SSA. The adsorption capacity of Sep samples was increased by mechanical treatments (ground and sonicated). Moreover, thermal activation led to additional increases in adsorption probably due to changes in the Sep structure by the loss of OH structural groups leading to a more hydrophobic surface. Diuron adsorption on Mt-TT samples produced an increase in the negative surface charge compared to the original sample, whereas a decrease in the negative surface charge was observed for Sep.

In this paper, the character of structural changes induced by different mechanical treatments to Prunus persica stones (PSs), and its subsequent effect on biosorption kinetics of Cu(II) were investigated. PSs were processed in vibratory disk mill (PS-V) and ultra-centrifugal mill (PS-C) and characterized by XRD, BET, SEM and FTIR spectroscopy. It was shown that PS-V was smaller and more reactive with less crystallinity index and hydrogen bond intensity compared to PS-C. In opposite, surface area of the PS-C was bigger than that of the PS-V. The total pore volume was about threefold, while the volume of micro pores was 9.29 times higher in PS-Cs than in PS-Vs. The kinetics of Cu(II) biosorption by both PSs was tested through various kinetic models: pseudo-first and pseudo-second order rate equations, Elovich equation, Boyd model, Weber-Morris and Urano-Tachikawa intraparticle diffusion model. For both sample types, Cu(II) biosorption occurred through combination of intraparticle and film diffusion mechanism, while kinetic results were best described by the pseudo-second order kinetic model. At the same time, the results indicated that together with kinetic rate the biosorption capacity of PS-C (21.20 mg g À1) was higher than that of PS-V (16.30 mg g À1). Mechanical activation like crushing and grinding will change material particle size, specific surface area and porosity, as well as its crystallinity. However, this paper elucidates that such physical

La diffraction des électrons rétrodiffusés (EBSD) et la microdiffraction Kossel sont deux techniques complémentaires pour l'analyse des contraintes internes à l'échelle sub-micronique dans les matériaux de structure et dans les composants de la microélectronique. L'objectif à terme est de dresser des cartographies de contraintes, par exemple au cours d'essai mécanique in-situ, en vue de l'identification multi-échelle du comportement local des matériaux. Les principes physiques et géométriques de ces deux techniques de diffraction sont brièvement présentés, puis les méthodologies d'analyse de déformation sont décrites. Enfin, des expériences de validation et quelques applications sont exposées.

Les matériaux nanocristallins présentent des propriétés de diffusion accrues dues à leur forte densité de joints de grain. Afin de maitriser totalement le processus de diffusion lors de traitements thermochimiques de tels matériaux, ces travaux s'attachent à donner un modèle de coefficient de diffusion macroscopique en fonction de la taille et de la forme des grain dans un polycristal. Ils s'appuient sur une technique d'homogénéisation effectuée après une analyse par éléments finis sur des volumes élémentaires représentatifs. On construit ainsi une expression analytique du coefficient de diffusion macro

This is the third and final part of the three-part article written to describe the mass, energy and material balances of the solid recovered fuel production process produced from various types of waste streams through mechanical treatment. This article focused the production of solid recovered fuel from municipal solid waste. The stream of municipal solid waste used here as an input waste material to produce solid recovered fuel is energy waste collected from households of municipality. This article presents the mass, energy and material balances of the solid recovered fuel production process. These balances are based on the proximate as well as the ultimate analysis and the composition determination of various streams of material produced in a solid recovered fuel production plant. All the process streams are sampled and treated according to CEN standard methods for solid recovered fuel. The results of the mass balance of the solid recovered fuel production process showed that 72% ...

This work shows some possibilities for using electron paramagnetic resonance in an experimental study of the role of mechanothermal effects in the formation of defect structures in dispersed systems during prolonged mechanical treatment of ZnO powders. The use of EPR for this purpose is based on the known fact that initiation of a number of paramagnetic centers occurs during mechanical treatment of some materials. Such centers can serve as EPR-sondes of different thermal processes appearing during mechanical treatment of systems containing ZnO.

This is the third and final part of the three-part article written to describe the mass, energy and material balances of the solid recovered fuel production process produced from various types of waste streams through mechanical treatment. This article focused the production of solid recovered fuel from municipal solid waste. The stream of municipal solid waste used here as an input waste material to produce solid recovered fuel is energy waste collected from households of municipality. This article presents the mass, energy and material balances of the solid recovered fuel production process. These balances are based on the proximate as well as the ultimate analysis and the composition determination of various streams of material produced in a solid recovered fuel production plant. All the process streams are sampled and treated according to CEN standard methods for solid recovered fuel. The results of the mass balance of the solid recovered fuel production process showed that 72% ...

This is the third and final part of the three-part article written to describe the mass, energy and material balances of the solid recovered fuel production process produced from various types of waste streams through mechanical treatment. This article focused the production of solid recovered fuel from municipal solid waste. The stream of municipal solid waste used here as an input waste material to produce solid recovered fuel is energy waste collected from households of municipality. This article presents the mass, energy and material balances of the solid recovered fuel production process. These balances are based on the proximate as well as the ultimate analysis and the composition determination of various streams of material produced in a solid recovered fuel production plant. All the process streams are sampled and treated according to CEN standard methods for solid recovered fuel. The results of the mass balance of the solid recovered fuel production process showed that 72% ...

Forest recovery on disturbed areas is of special significance in the Ecuadorian Andes, where deforestation is a serious problem. Natural diachronic succession was evaluated on three large plots or sites, differing in their land use and vegetation composition, one is dominated by grass species on an abandoned pasture (Pasture site), the other two are post-fire vegetation dominated by bracken (Bracken site) and various shrubs (Shrub site). Additionally, we assessed the effectiveness of manual removal of competitive herbaceous species to accelerate forest recovery. Monitoring was done in 2003, 2005 and 2007 on 48 subplots of 116 m 2 each recording species richness and woody-species density. Results showed that the Pasture site demonstrated a competitive effect of exotic grasses on woody species recruitment with much lower species recruitment and density, suggesting serious inhibition of natural forest regeneration and an unclear successional trajectory. The Bracken and Shrub sites became significantly similar floristically and there is evidence for a marked facilitation of woody plant recruitment correlated with light availability on the ground. Both sites showed characteristics of classic succession, with Shrub showing a higher species richness and density while late-successional species are poorly represented on the Bracken site. However, NMDS ordination using species density showed that the two trajectories may not be converging towards a common ''final state''. Manual weeding was ineffective for accelerating forest recovery. These results suggest that the main limiting factor for the recruitment of woody species on the Pasture site is strong grass competition and must be addressed before seed availability, while seed availability seems to be the

Des travaux scientifiques récents ont ouvert de nouveaux champs d’application aux traitements mécaniques tels que le grenaillage. Il a été montré que de tels traitements, réalisés avant un traitement de nitruration à la surface d’alliage ferreux, permettaient d’abaisser les températures de traitement et d’augmenter significativement les cinétiques de diffusion. Nous avons entrepris de tester les performances de cette combinaison de traitements mécanique et thermochimique sur des aciers inoxydables et des alliages à base nickel austénitiques. Des essais ont été réalisés à partir d’une technique de grenaillage mécanique appelée « Surface Mechanical Attrition Treatment » (SMAT). Des billes en métal ou en céramique sont introduites dans l’enceinte et mises en mouvement par la sonotrode. Les billes percutent et introduisent donc une déformation plastique à la surface des échantillons. Après cette étape, les échantillons subissent un traitement thermochimique de nitruration assisté plasma...

This paper attempts to improve the physical and mechanical properties of selective laser sintered polyamide PA2200 components through a vibratory surface finishing process by inducing severe plastic deformation at the outer surface layers. The industrial target of additive manufacturing components is to obtain structures having surface roughness, hardness, and other mechanical properties equivalent to or better than those produced conventionally. Compared to the as-built SLS PA2200 samples, vibratory surface finishing treated specimens exhibited a smooth surface microstructure and more favorable roughness, hardness, and tensile strength. Also, the duration of the vibratory surface finishing process showed a further improvement in the surface roughness and hardness of the SLS samples. Compared to the as-built state, the roughness and hardness of the surface-treated samples improved by almost 90% and 15%, respectively. Consequently, microstructural analysis indicates that lower surfac...

Avant-propos Ce travail de doctorat a été financé en partie par l'intermédiaire d'une subvention CIFRE accordée par l'ANRT à la société AREVA NP. Le laboratoire d'accueil fut dans un premier temps le Laboratoire de Science et Génie des Surfaces (LSGS, UMR 7570) dirigée par M. Bauer. Par la suite, le LSGS a fusionné avec quatre autres laboratoires de Nancy pour former l'Institut Jean Lamour (IJL, UMR CNRS 7198) dirigée par M. Dubois. Ce travail a été réalisé à la fois à l'IJL et au Centre technique département Chimie corrosion d'AREVA NP du Creusot dirigé par M. Foucault. Je remercie toutes ces personnes de m'avoir accueilli tour à tour au sein de leur unité. Je tiens vivement à remercier messieurs Maxence Bigerelle et Patrick Villechaise d'avoir bien voulu examiner, rapporter le présent manuscrit qui est le fruit de trois années de travail. Je les remercie pour l'intérêt qu'ils ont porté à étudier mon travail dans les moindres détails. J'adresse toute ma gratitude à M. Abdelkrim Redjaimia pour m'avoir fait l'honneur de présider le Jury. Je remercie aussi tous les autres membres du jury, MM. Marc Foucault, Philippe Gilles pour avoir pris le temps d'examiner mon travail. Je remercie vivement l'équipe de direction de la thèse composée de Messieurs Thierry Belmonte, Thierry Czerwiec et Dominique Hertz sans qui cette étude n'aurait pas vu le jour. J'ai apprécié leur disponibilité et leur présence. Ils ont su me faire partager leur culture et savoir scientifiques, me réorienter lorsque je m'écartais du sujet, me conseiller sur les démarches et méthodes à suivre. Ils m'ont aussi ouvert les portes sur le monde de la recherche et du développement tant du point de vue universitaire qu'industriel. Par ces quelques lignes, je souhaite également remercier toutes les personnes qui ont contribué de façon directe ou indirecte à la réalisation et au bon déroulement de mes travaux. Je remercie également l'équipe AREVA composée de Mme. Marylise Caron-Charles, M. Marc Foucault et M. Philippe Gilles pour leur implication et le suivi du déroulement de la thèse au cours de ces années. Ils m'ont permis de comprendre les implications de mon travail dans l'industrie. Je remercie vivement M. Grégory Marcos, qui s'est impliqué dans le suivi de la thèse dès le début. Je le remercie également pour toutes les fois où il m'a permis de me sortir de certaines situations critiques. Les ingénieurs en charge des techniques de caractérisations telles que P. Boulet (DRX), B. Brugier (MEB-EBSD), C. Gendarme (MEB), S. Migot (MET), T. Toll Duchanoy (métallurgie et MET) et S. Weber mais aussi les techniciens du laboratoire, B. Boreux (préparation des échantillons et nanoindentation) et J.P. Arnould (tribologie) sont des personnes que je remercie chaleureusement pour leur patience, le temps qu'ils ont passé avec moi à répondre à mes questions, mes interrogations et à satisfaire ma curiosité. Ils m'ont permis de découvrir et comprendre les limites inhérentes à chaque technique de caractérisations que j'ai employée. Au cours de ces trois année, j'ai eu également la chance de rencontrer bon nombre de spécialistes avec qui j'ai pu discuter et pour certain j'ai pu leur présenter mes travaux. Leur expérience et leur connaissance m'ont permis de comprendre de nombreux phénomènes IV physiques et ils m'ont aidé dans l'interprétation des résultats que j'obtenais. C'est pourquoi, je tiens à remercier pour leur précieux aide et conseil, Mme Allain Bonasso, MM.

In order to release proteins in the aqueous phase, high-pressure homogenization and alkaline treatments were applied to rupture the cell walls of five intensively grown microalgae. Protein characterisation was carried out by analysing the amino acid profiles of both the crude microalgae and the protein extracts, obtained after both types of treatment. The results showed that the proportion of proteins released from microalgae following both treatments was, in descending order: Porphyridium cruentum N Arthrospira platensis N Chlorella vulgaris N Nannochloropsis oculata N Haematococcus pluvialis, reflecting the increasingly protective, cell walls. Nonetheless, mechanical treatment released more proteins from all the microalgae compared to chemical treatment. The highest yield was for the fragile cell walled P. cruentum with 88% hydro-soluble proteins from total proteins, and the lowest from the rigid cell walled H. pluvialis with 41%. The proportion of essential and non-essential amino acids in the extract was assessed and compared to the crude microalgae profile. It was higher after alkaline treatment and much higher after high-pressure homogenization. These results suggest that non-essential amino acids are more concentrated actually inside the cells and that different types of proteins are being released by these two treatments.

Vibratory ball milling is shown to have a strong influence on the shape of FT-IR spectra of wood and cellulose, even if the samples are milled for only a short time. The results show that neither temperature nor particle size or oxidation processes are the most important reason for the observed changes in the structure of the FT-IR spectra, but that the mechanical treatment itself is the main influencing factor. Studies of the effects of temperature, particle size, oxygen and mechanical treatment on chemical and structural ...

Vibratory ball milling is shown to have a strong influence on the shape of FT-IR spectra of wood and cellulose, even if the samples are milled for only a short time. The results show that neither temperature nor particle size or oxidation processes are the most important reason for the observed changes in the structure of the FT-IR spectra, but that the mechanical treatment itself is the main influencing factor. Studies of the effects of temperature, particle size, oxygen and mechanical treatment on chemical and structural ...

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright The evolution of structural–morphological characteristics of ZnO + 1 wt.% MnO 2 and ZnO + 10 wt.% MnO 2 samples during prolonged mechanical treatment (MT) was investigated by X-ray, AFM, LPS, SEM and IR methods. Changes in crystallite size due to mechanical activation were determined from X-ray measurements. These results were correlated with changes in particle size followed by SEM and AFM. Particle and aggregate size distributions were determined from LPS measurements. Interpretation of the evolution of IR-absorption peaks during mechanical activation using the theory of average dielectric constants enabled analysis of changes of particle and agglomerate shapes. All these results enabled establishment of a relationship between crystallites, particles, aggregates of particles, and superficial processes that occur during mechanical activation.

Using of EPR the laws of formation of various defects during mechanical treatment (MT) of powders of zinc oxide were considered. Formation of six different types of paramagnetic centers was established. The quantitative analysis of the changes of intensity (concentration of the centers in the sample) of EPR signals I-VI depending on conditions of MT (speed of rotation of jars of a mill, duration of MT, amount of entered additives, etc.) has allowed to establish interrelation between defects formation and temperature processes, which develop during MT. In the work the opportunities of an obtaining of samples with a necessary set of surface defects are discussed.