Nuria Llorca-Isern - Academia.edu (original) (raw)

Uploads

Papers by Nuria Llorca-Isern

Materials Characterization, 2022

Materials Characterization, Feb 1, 2016

Thermal spray, May 8, 2000

The influence of plasma spraying parameters on the mechanical properties of coatings has been stu... more The influence of plasma spraying parameters on the mechanical properties of coatings has been studied. ZrO2-Y2O3 coatings were sprayed onto stainless steel and aluminium substrates at temperatures of about 75°C and 225°C. An original set of samples, facilitating the measurement of substrate deflection, was used to evaluate the effect of thermal cycling under different spraying conditions. In order to correlate thermal cycling values and mechanical properties to coating microstructure, the coatings were impregnated with low-viscosity resin and examined under a confocal microscope. The results reveal the influence of spraying temperature, substrate properties, and torch-substrate velocity on coating damage.

Practical Metallography, Apr 1, 1990

Marine Pollution Bulletin, Jun 1, 2021

Materials Letters, Oct 1, 2016

Materials Science Forum, Dec 1, 2018

Industrial application of superhydrophobic surfaces is limited by the unsatisfactory mechanical p... more Industrial application of superhydrophobic surfaces is limited by the unsatisfactory mechanical properties of the material. Combining chemical etching and anodization terraced features containing aluminium oxide on different aluminium alloy surfaces were produced. After modified by fatty acid, the surfaces were superhydrophobic and they showed self-cleaning effect. The highest contact angle was obtained after forming hierarchical structures with a solution free of fluorine compounds; therefore, the process is considered eco-friendly. The alumina formed in the coating process promotes an improved corrosion resistance. The present study has three main objectives: to identify the molecules responsible for superhydrophobicity, the mechanism by which superhydrophobicity is produced, and consequently the influence of variables such as anodization time on the proposed processing method. We use time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS) techniques to identify each compound involved in the final surface, by paying close attention to the analysis of the mechanism by which the chemical reaction proceeds. The morphology of the superhydrophobic surfaces was further observed by scanning electron microscope (SEM) and atomic force microscopy and was used to elucidate the effect of the anodization time in the properties of the superhydrophobic material.

Materials Science Forum, Dec 1, 2018

This study develops a new, facile and rapid process bioinspired on rice leaf with the aim of prod... more This study develops a new, facile and rapid process bioinspired on rice leaf with the aim of producing a hybrid composite coating in a first attempt to obtain a superhydrophobic coating with enhanced erosion resistance properties. Rice leaves (Oryza sativa L.) are made of hierarchical structures consisting of micropapillae and waxy nanobumps which confer to the surface a contact angle of 164° as Lotus leaf does. In particular, rice leaves accumulate amorphous silica inside and on the surface with various morphologies. This kind of silica is produced by absorbing silicates from the soil under specific conditions of temperature and pressure. The presence of biosilica in rice leaves is useful for preventing diseases or improves mechanical properties of the leaves. Single-step and two-step processes are the two strategies applied for generating a superhydrophobic coating by electrochemical deposition of ZnCl2, α-Al2O3 and lauric acid (C11H23COOH) onto commercial pure aluminum substrate. The static contact angle measured on the coating gives values of 170° and 1° for the sliding angle conducing to a coating with superhydrophobic and self-cleaning properties. Various characterization techniques are used to determine chemical and morphological structure such as FESEM, XPS or FTIR. On one hand, in morphological analysis, flower-like structure is obtained with petals thickness of 70nm corresponding to the nanostructured contribution to the system. On the other hand, chemical analysis concludes the generation of zinc laurate (Zn (C11H23COO)2) as a major compound contributing to the reduction of surface tension and increasing the superhydrophobic character of the coating as well.

Journal of Alloys and Compounds, Dec 1, 2017

Elsevier eBooks, 2013

Abstract: Since the early 1990s considerable effort has been devoted to the development of metal-... more Abstract: Since the early 1990s considerable effort has been devoted to the development of metal-based composite powders (MeCP). Reinforcements in MeCP can vary from intermetallic to ceramic or polymer, depending on composition and can also be microstructured or nanostructured, depending on the size of the constituent materials. Composite powders can be used at the macro- and microscale to produce dense composite objects, composite coatings, to provide a combination of properties in one component or to provide specific properties to withstand extreme conditions in service. In addition to this, technology for the synthesis of nanodevices has also evolved. Metal composite powders are produced by a variety of methods based on solid-, liquid- and gas-phase synthesis and mechanosynthesis. Functionality and design are the current drivers for the development of metal composite powders.

International Journal of Metalcasting, Feb 25, 2016

International Journal of Metalcasting, Feb 23, 2016

Materials Characterization, Apr 1, 1991

HAL (Le Centre pour la Communication Scientifique Directe), 2004

ABSTRACT

Journal of Superconductivity and Novel Magnetism, May 15, 2020

Este estudio tiene como principal objetivo conocer desde una perspectiva comparada la realidad no... more Este estudio tiene como principal objetivo conocer desde una perspectiva comparada la realidad normativa y socio-educativa de la adopcion internacional (AI) en Espana y, mas concretamente, en la Comunidades Autonomas de Aragon, Cataluna y Valencia. La AI ha sido un fenomeno social en Espana en los ultimos anos. Su regulacion esta en estos momentos pendiente del desarrollo reglamentario de la Ley 26/2015. Esta pretende centralizar la regulacion del procedimiento adoptivo y la acreditacion y control de los organismos que se encargan de llevarlo a cabo (las antiguas ECAI). Hasta ahora estas cuestiones eran competencia de las Comunidades Autonomas y es el momento oportuno para realizar un analisis de las diferentes experiencias. La revision de la literatura presenta la AI como un poderoso mecanismo protector que permite contrarrestar el efecto de los posibles factores de riesgo. Para que ello ocurra se debe atender adecuadamente las posibles necesidades del nino y de sus familiares. Sin embargo, el seguimiento postadoptivo no siempre cubre las demandas, depende no solo de la legislacion de cada Comunidad sino tambien de los requisitos establecidos por el pais de origen del nino. Las familias muchas veces recurren a las asociaciones en busca de ayuda, incluso se han llegado a constituir unidades hospitalarias especializadas a tal fin. Es por todo ello que se ha realizado un estudio comparado de la situacion actual de la AI en estas Comunidades Autonomas siguiendo el metodo de Ferrer (2002). Se ha analizado la normativa autonomica que regula la AI en estas tres Comunidades y se ha establecido que organismos, tanto publicos como privados, intervienen. Tambien se ha estudiado el procedimiento concreto en cada unidad y se ha preguntado a los agentes sociales que intervienen en el proceso (la administracion, las ECAI, las asociaciones de padres y las unidades hospitalarias especializadas) su percepcion sobre las necesidades que presentan los ninos y sus familias y la cobertura que ofrecen. Los resultados obtenidos muestran que los ambitos educativos y linguisticos parecen ser los menos atendidos, aunque son fundamentales para el exito escolar de los ninos adoptados internacionalmente y para el bienestar de sus familias. Se pone de manifiesto, pues, que el sistema educativo debe establecer medidas con caracter general para garantizar la equidad de estos alumnos y conseguir su inclusion.

Materials Science Forum, Nov 1, 2016

Superhydrophobic surfaces, with extremely high water contact angles (CAs) of more than 150° are o... more Superhydrophobic surfaces, with extremely high water contact angles (CAs) of more than 150° are of special interest due to their various anti-adhesive and self-cleaning properties. Recent studies demonstrate that the superhydrophobicity principally results from the presence of binary structures at both the micrometre and nanometre scales together with the low-energy wax-like materials on the surfaces. Materials with similar properties, to those of the lotus leaf structure are very useful in several areas, such as the aeronautical industry and civil engineering; so many methods have been developed to mimic the lotus leaf structure. Metals are very important and irreplaceable engineered materials in many industrial fields. An alternative method for enhancing superhydrophobicity on different metals is proposed. The method proceeds by coating the metallic surface with a superhydrophobic reactive such as dodecanoic acid being a common application its use in paints with eco-friendly properties. The goal of this study is to induce direct superhydrophobicity by a single step and coating process on prepared surfaces of pure commercial aluminium 99.9 wt %, pure commercial 99.9 wt % copper and stainless steel grade 316L (UNS S31603). The chemical reaction proceeds by etching the activated surface with lauric acid in ethanol solutions.

International Journal of Metalcasting, Dec 19, 2016

Microplastics are a global issue that affects the environment, economy, as well as human health. ... more Microplastics are a global issue that affects the environment, economy, as well as human health. Herein, we present a superhydrophobic 304 stainless steel mesh obtained by chemical etching followed by a liquid-phase deposition of lauric acid that can be used for microplastic removal. Field emission scanning electron microscopy (FE-SEM) and high-resolution X-ray photoelectron spectroscopy (HR-XPS), among other techniques, were used to identify the hierarchical structure and chemical composition of the surface. They revealed that iron laurate decreased the surface free energy. The 304 stainless steel mesh was superhydrophobic (169°) and superoleophilic (0°). Taking advantage of these wetting properties, we showed an innovative use of these superhydrophobic surfaces in the removal of microplastics. Additionally, we analyzed the removal efficiency from a surface and colloidal point of view that allowed us to explain and clarify why microplastics can also be removed by their wetting properties. The loss of a double electrostatic cloud between the microplastics and the predominance of van der Waals interactions in the organic phase promote the removal of these persistent pollutants from water.

Materials Characterization, 2022

Materials Characterization, Feb 1, 2016

Thermal spray, May 8, 2000

The influence of plasma spraying parameters on the mechanical properties of coatings has been stu... more The influence of plasma spraying parameters on the mechanical properties of coatings has been studied. ZrO2-Y2O3 coatings were sprayed onto stainless steel and aluminium substrates at temperatures of about 75°C and 225°C. An original set of samples, facilitating the measurement of substrate deflection, was used to evaluate the effect of thermal cycling under different spraying conditions. In order to correlate thermal cycling values and mechanical properties to coating microstructure, the coatings were impregnated with low-viscosity resin and examined under a confocal microscope. The results reveal the influence of spraying temperature, substrate properties, and torch-substrate velocity on coating damage.

Practical Metallography, Apr 1, 1990

Marine Pollution Bulletin, Jun 1, 2021

Materials Letters, Oct 1, 2016

Materials Science Forum, Dec 1, 2018

Industrial application of superhydrophobic surfaces is limited by the unsatisfactory mechanical p... more Industrial application of superhydrophobic surfaces is limited by the unsatisfactory mechanical properties of the material. Combining chemical etching and anodization terraced features containing aluminium oxide on different aluminium alloy surfaces were produced. After modified by fatty acid, the surfaces were superhydrophobic and they showed self-cleaning effect. The highest contact angle was obtained after forming hierarchical structures with a solution free of fluorine compounds; therefore, the process is considered eco-friendly. The alumina formed in the coating process promotes an improved corrosion resistance. The present study has three main objectives: to identify the molecules responsible for superhydrophobicity, the mechanism by which superhydrophobicity is produced, and consequently the influence of variables such as anodization time on the proposed processing method. We use time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS) techniques to identify each compound involved in the final surface, by paying close attention to the analysis of the mechanism by which the chemical reaction proceeds. The morphology of the superhydrophobic surfaces was further observed by scanning electron microscope (SEM) and atomic force microscopy and was used to elucidate the effect of the anodization time in the properties of the superhydrophobic material.

Materials Science Forum, Dec 1, 2018

This study develops a new, facile and rapid process bioinspired on rice leaf with the aim of prod... more This study develops a new, facile and rapid process bioinspired on rice leaf with the aim of producing a hybrid composite coating in a first attempt to obtain a superhydrophobic coating with enhanced erosion resistance properties. Rice leaves (Oryza sativa L.) are made of hierarchical structures consisting of micropapillae and waxy nanobumps which confer to the surface a contact angle of 164° as Lotus leaf does. In particular, rice leaves accumulate amorphous silica inside and on the surface with various morphologies. This kind of silica is produced by absorbing silicates from the soil under specific conditions of temperature and pressure. The presence of biosilica in rice leaves is useful for preventing diseases or improves mechanical properties of the leaves. Single-step and two-step processes are the two strategies applied for generating a superhydrophobic coating by electrochemical deposition of ZnCl2, α-Al2O3 and lauric acid (C11H23COOH) onto commercial pure aluminum substrate. The static contact angle measured on the coating gives values of 170° and 1° for the sliding angle conducing to a coating with superhydrophobic and self-cleaning properties. Various characterization techniques are used to determine chemical and morphological structure such as FESEM, XPS or FTIR. On one hand, in morphological analysis, flower-like structure is obtained with petals thickness of 70nm corresponding to the nanostructured contribution to the system. On the other hand, chemical analysis concludes the generation of zinc laurate (Zn (C11H23COO)2) as a major compound contributing to the reduction of surface tension and increasing the superhydrophobic character of the coating as well.

Journal of Alloys and Compounds, Dec 1, 2017

Elsevier eBooks, 2013

Abstract: Since the early 1990s considerable effort has been devoted to the development of metal-... more Abstract: Since the early 1990s considerable effort has been devoted to the development of metal-based composite powders (MeCP). Reinforcements in MeCP can vary from intermetallic to ceramic or polymer, depending on composition and can also be microstructured or nanostructured, depending on the size of the constituent materials. Composite powders can be used at the macro- and microscale to produce dense composite objects, composite coatings, to provide a combination of properties in one component or to provide specific properties to withstand extreme conditions in service. In addition to this, technology for the synthesis of nanodevices has also evolved. Metal composite powders are produced by a variety of methods based on solid-, liquid- and gas-phase synthesis and mechanosynthesis. Functionality and design are the current drivers for the development of metal composite powders.

International Journal of Metalcasting, Feb 25, 2016

International Journal of Metalcasting, Feb 23, 2016

Materials Characterization, Apr 1, 1991

HAL (Le Centre pour la Communication Scientifique Directe), 2004

ABSTRACT

Journal of Superconductivity and Novel Magnetism, May 15, 2020

Este estudio tiene como principal objetivo conocer desde una perspectiva comparada la realidad no... more Este estudio tiene como principal objetivo conocer desde una perspectiva comparada la realidad normativa y socio-educativa de la adopcion internacional (AI) en Espana y, mas concretamente, en la Comunidades Autonomas de Aragon, Cataluna y Valencia. La AI ha sido un fenomeno social en Espana en los ultimos anos. Su regulacion esta en estos momentos pendiente del desarrollo reglamentario de la Ley 26/2015. Esta pretende centralizar la regulacion del procedimiento adoptivo y la acreditacion y control de los organismos que se encargan de llevarlo a cabo (las antiguas ECAI). Hasta ahora estas cuestiones eran competencia de las Comunidades Autonomas y es el momento oportuno para realizar un analisis de las diferentes experiencias. La revision de la literatura presenta la AI como un poderoso mecanismo protector que permite contrarrestar el efecto de los posibles factores de riesgo. Para que ello ocurra se debe atender adecuadamente las posibles necesidades del nino y de sus familiares. Sin embargo, el seguimiento postadoptivo no siempre cubre las demandas, depende no solo de la legislacion de cada Comunidad sino tambien de los requisitos establecidos por el pais de origen del nino. Las familias muchas veces recurren a las asociaciones en busca de ayuda, incluso se han llegado a constituir unidades hospitalarias especializadas a tal fin. Es por todo ello que se ha realizado un estudio comparado de la situacion actual de la AI en estas Comunidades Autonomas siguiendo el metodo de Ferrer (2002). Se ha analizado la normativa autonomica que regula la AI en estas tres Comunidades y se ha establecido que organismos, tanto publicos como privados, intervienen. Tambien se ha estudiado el procedimiento concreto en cada unidad y se ha preguntado a los agentes sociales que intervienen en el proceso (la administracion, las ECAI, las asociaciones de padres y las unidades hospitalarias especializadas) su percepcion sobre las necesidades que presentan los ninos y sus familias y la cobertura que ofrecen. Los resultados obtenidos muestran que los ambitos educativos y linguisticos parecen ser los menos atendidos, aunque son fundamentales para el exito escolar de los ninos adoptados internacionalmente y para el bienestar de sus familias. Se pone de manifiesto, pues, que el sistema educativo debe establecer medidas con caracter general para garantizar la equidad de estos alumnos y conseguir su inclusion.

Materials Science Forum, Nov 1, 2016

Superhydrophobic surfaces, with extremely high water contact angles (CAs) of more than 150° are o... more Superhydrophobic surfaces, with extremely high water contact angles (CAs) of more than 150° are of special interest due to their various anti-adhesive and self-cleaning properties. Recent studies demonstrate that the superhydrophobicity principally results from the presence of binary structures at both the micrometre and nanometre scales together with the low-energy wax-like materials on the surfaces. Materials with similar properties, to those of the lotus leaf structure are very useful in several areas, such as the aeronautical industry and civil engineering; so many methods have been developed to mimic the lotus leaf structure. Metals are very important and irreplaceable engineered materials in many industrial fields. An alternative method for enhancing superhydrophobicity on different metals is proposed. The method proceeds by coating the metallic surface with a superhydrophobic reactive such as dodecanoic acid being a common application its use in paints with eco-friendly properties. The goal of this study is to induce direct superhydrophobicity by a single step and coating process on prepared surfaces of pure commercial aluminium 99.9 wt %, pure commercial 99.9 wt % copper and stainless steel grade 316L (UNS S31603). The chemical reaction proceeds by etching the activated surface with lauric acid in ethanol solutions.

International Journal of Metalcasting, Dec 19, 2016

Microplastics are a global issue that affects the environment, economy, as well as human health. ... more Microplastics are a global issue that affects the environment, economy, as well as human health. Herein, we present a superhydrophobic 304 stainless steel mesh obtained by chemical etching followed by a liquid-phase deposition of lauric acid that can be used for microplastic removal. Field emission scanning electron microscopy (FE-SEM) and high-resolution X-ray photoelectron spectroscopy (HR-XPS), among other techniques, were used to identify the hierarchical structure and chemical composition of the surface. They revealed that iron laurate decreased the surface free energy. The 304 stainless steel mesh was superhydrophobic (169°) and superoleophilic (0°). Taking advantage of these wetting properties, we showed an innovative use of these superhydrophobic surfaces in the removal of microplastics. Additionally, we analyzed the removal efficiency from a surface and colloidal point of view that allowed us to explain and clarify why microplastics can also be removed by their wetting properties. The loss of a double electrostatic cloud between the microplastics and the predominance of van der Waals interactions in the organic phase promote the removal of these persistent pollutants from water.