NiTi splat features during Vacuum Thermal Spraying onto several substrates

Vacuum Plasma Spraying (VPS) has been used to produce coatings onto steel substrates. This work deals with the study of splat morphology of the NiTi alloy sprayed by VPS onto different substrates (aluminium, copper, stainless steel, glass and alumina). All the previous characteristics are discussed in terms of wettability and thermal conductivities regarding the rapid cooling involved in the process. Although identical conditions were used during thermal spraying, a wide variety of splat formations were observed; commonly, slushy or splash/disc splats are formed depending on whether the particles have partially or fully melted. The thermal effusivity of the substrate material, which is a measure of its ability to exchange thermal energy with its surroundings, seems to play an important role promoting more or less spreading. The higher the thermal effusivity is, the more rapidly the splats are cooled, thus starting the solidification before they come to rest and, changing their morphology

Ordering kinetics evaluation of FeAl powders

In this study, time resolved X-ray diffraction experiments using synchrotron X-ray radiation have been performed to get insight on the time and temperature dependent atomic ordering of an intermetallic Fe-40A1 (at.%) ball-milled powder. The target of the present study is to gain knowledge on the rapid heating processes occurring during Thermal Spray coating processes. Present results show that in the temperature range 400 degrees C - 550 degrees C, the evolution of the order can be followed and modelled by fitting the powder diffraction patterns collected within the first minutes after fast heating. Reasonable refinements have been obtained by assuming the presence of two domains corresponding to the ordered and disordered lattices. The lattice constant changes from 0.29165 nm in the ball-milled powder at room temperature to 0.29281 nm in the ordered phase after 3000 s at 550 degrees C. The growth of the ordered phase is proposed to be a vacancy-related process with an activation energy of 1.04 eV. Above 550 degrees C, the ordering kinetics appears too fast to be resolved using the few seconds time scale of the present experiments which is in agreement to thermal spray results conditions

Estudi d'algunes ferrites hexagonals uniaxials

[cat] S'ha obtingut la comprensió dels fenòmens donant lloc a l'ordenament magnètic i l'anisotropia magnetocristal.lina de ferrites hexagonals uniaxials. S'han realitzat mesures de difracció de raigs X i de neutrons (per afinar l'estructura i l'ordenament magnètic), mesures magnètiques en funció de la temperatura (permetent determinar imantació a saturació amb la llei d'aproximació a la saturació, i anisotropia magnetocristal.lina per detecció del punt singular), i mesures d'espectroscòpia Mössbauer (per determinar el comportament del Fe3+ en diferents llocs de l'estructura). Per la ferrita tipus M BaFe12O19, les dades estructurals han permès realitzar el càlcul de les interaccions dipolars entre els spins dels ions, justificant l'anisotropia magnetocristal.lina a baixa temperatura. S'han obtingut les interaccions d'intercanvi entre els Fe3+ de dades d'espectroscòpia Mössbauer en funció de la temperatura, que justifiquen el comportament magnètic en funció de la temperatura. Els resultats permeten explicar el comportament del LaZnFe11O19 i de la família SrFe12-xCrxO19 per x menor que 8. Les propietats de l'estructura R BaMn2Fe4O11 són coherents amb les de l'estructura M.[spa] Se ha obtenido la comprensión de los fenómenos dando lugar al ordenamiento magnético y la anisotropía magnetocristalina en ferritas hexagonales uniaxiales. Se han realizado medidas de difracción de rayos X y de neutrones (para afinar la estructura y el ordenamiento magnético), medidas magnéticas en función de la temperatura (permitiendo determinar imanación a saturación por medio de la ley de aproximación a la saturación, y anisotropía magnetocristalina por detección del punto singular), y medidas de espectroscopia Mössbauer (para determinar el comportamiento del Fe3+ en diferentes posiciones de la estructura). Para la ferrita tipo M BaFe12O19, los datos estructurales han permitido realizar el cálculo de las interacciones dipolares entre los spines de los iones, justificando la anisotropía magnetocristalina a baja temperatura. Se han obtenido las interacciones de intercambio entre los Fe3+ a partir de datos de espectroscopia Mössbauer en función de la temperatura, que justifican el comportamiento magnético en función de la temperatura. Los resultados permiten explicar el comportamiento del LaZnFe11O19 y de la serie SrFe12-xCrxO19 para x menor que 8. Las propiedades de la estructura R BaMn2Fe4O11 son coherentes con las de la estructura M.[eng] The aim has been the understanding of phenomena giving rise to the magnetic ordering and magnetocrystalline anisotropy in uniaxial hexaferrites. Measurements of X-ray and neutron diffraction (to refine structure and magnetic ordering), magnetization as function of temperature (to obtain magnetization to saturation with the law of approach to saturation, and magnetocristalline anisotropy with the singular point detection), and Mössbauer spectroscopy (to determine the behaviour of Fe3+ in different places of structure), have been done. For the M ferrite BaFe12O19, structural data has allowed the computation of dipolar interactions among ionic spins, justifying magnetocrystalline anisotropy at low temperatures. Exchange interactions among Fe3+ have been obtained from Mössbauer data as function of temperature, explaining the magnetic behaviour as function of temperature. The results explain the behaviour of LaZnFe11O19 and the series SrFe12-xCrxO19 for x less than 8. The properties of the R-structure BaMn2Fe4O11 are coherent with the properties of the M structure.

Cation distribution and high field magnetization studies on SrFe12-xCrxO19

With the aim of a better understanding of both cationic distribution and magnetic properties of the uniaxial SrFe12-xCrxO19hexagonal ferrites, Mössbauer spectroscopy, neutron diffraction and high field magnetization measurements have been carried out. The Cr3+ions occupy the octahedral sites of the M structure with a preference hierarchy within them. The magnetic measurements, together with the deduced cationic distribution, indicate that some sublattices have a random spin canting around the c-axis

Data Analysis for the Development of an Automatic Vessel Control System in a Port Area

[Resumen] Según el último informe de la Agencia Europea de Seguridad Marítima (EMSA), un gran número de incidentes de navegación con víctimas se producen en instalaciones portuarias. Para minimizar el número de accidentes es necesario contar con algoritmos de control eficientes que permitan decidir acciones en tiempo real por parte del operador. Se presentan las principales fuentes de los datos que permiten un control efectivo del control portuario. Se discuten las ventajas e inconvenientes de los datos suministrados por los sistemas AIS y RADAR. A partir de los requerimientos de seguridad para evitar colisiones, se analizan los principales datos relacionados con la embarcación y su entorno que son relevantes para un algoritmo eficiente del control de tráfico en puertos.[Abstract] According to the latest report from the European Maritime Safety Agency, a large number of boating incidents with casualties occur at port facilities. To minimize the number of accidents, it is necessary to have efficient control algorithms that allow the operator to decide actions in real time. The main sources of data that allow an effective control of port control are presented. The advantages and disadvantages of the data supplied by the AIS and RADAR systems are discussed. Based on the safety requirements to avoid collisions, the main data related to the vessel and its environment that are relevant for an efficient algorithm of traffic control in ports are analyzed.https://doi.org/10.17979/spudc.978849749804

CEMS and Faraday rotation study of gamma-Fe2O3-Fe3O4 films obtained by a new pyrolisis technique

Postprint (published version

Ordering kinetics evaluation of FeAl powders

In this study, time resolved X-ray diffraction experiments using synchrotron X-ray radiation have been performed to get insight on the time and temperature dependent atomic ordering of an intermetallic Fe-40A1 (at.%) ball-milled powder. The target of the present study is to gain knowledge on the rapid heating processes occurring during Thermal Spray coating processes. Present results show that in the temperature range 400 degrees C - 550 degrees C, the evolution of the order can be followed and modelled by fitting the powder diffraction patterns collected within the first minutes after fast heating. Reasonable refinements have been obtained by assuming the presence of two domains corresponding to the ordered and disordered lattices. The lattice constant changes from 0.29165 nm in the ball-milled powder at room temperature to 0.29281 nm in the ordered phase after 3000 s at 550 degrees C. The growth of the ordered phase is proposed to be a vacancy-related process with an activation energy of 1.04 eV. Above 550 degrees C, the ordering kinetics appears too fast to be resolved using the few seconds time scale of the present experiments which is in agreement to thermal spray results conditions