Production and characterization of ZrCN-Ag coatings deposited by mganetron sputtering

Tese de Doutoramento (Programa doutoral em Engenharia de Materiais)Zr-C-N coatings, incorporating silver as antibacterial agent, are deposited onto stainless steel 316L (SS316L) and Si (100) substrates by unbalanced magnetron sputtering; their corrosion and tribological properties were evaluated to understand their potential to be used in joint orthopedic devices. Zirconium carbonitride was selected owing to both its excellent biocompatibility and non-toxic behavior. Despite ZrCN has been widely studied, no other report on the deposition and characterization of Zr-C-N-Ag coatings exist in the literature, to the author knowledge. Therefore, the contribution of this project for the state of the art on Zr-C-N system alloyed novel metallic elements is: (i) A structural characterization, including the phase composition, based on the identification of crystalline (X-ray diffraction and transmission electron microscopy) and amorphous phases (Raman spectroscopy), and the chemical composition of the material both in bulk (electron probe microanalysis) and at the surface (X-ray photonelectron spectroscopy). The morphology of the coatings was also studied (scanning electron microscopy), in order to evidence the influence of the deposition parameters on the coatings cross-section and surface morphology, and correlate them with the functional properties. (ii) In order to optimize the adhesion, mechanical and electrochemical properties of the coatings; an optimization method was applied to the deposition process to decrease the final number of coating runs. (iii) The in-depth electrochemical and tribological characterization of the coatings was performed in a Hank’s balanced salt solution with 10 gr/L of bovine serum albumin, in order to mimic as much as possible the condition of the biological fluid of human body. In Zr-C-N-Ag system a diversity of phases can occur, such as zirconium carbonitride (ZrCN), amorphous carbon (a-C or a-(C, N)) and metallic silver (Ag). By controlling the deposition conditions, it is possible to adjust the amount of each phase, and then, to tune the properties of the system. The optimization of the deposition process shows that the ideal composition of the Zr-C-N-Ag coatings is attained when the Zr2CN phase is deposited, with less than 8 at. % of silver nanoparticles, allowing achieving the best compromise between mechanical, electrochemical and tribological properties. The electrochemical evaluation reveals that both silver and amorphous carbon phases are detrimental to the corrosion resistance. The increase of silver triggers a more active electrochemical reactions in the system that increases the corrosion process. In addition, the combination of silver and amorphous phases produces a more electrochemical porous materials, which promotes the penetration of the electrolyte. Although marginally, silver also negatively affects the wear resistance of the system, when tested against an ultra-high molecular weight polyethylene, due to a delay it causes in the formation of a protective albumin layer. The coefficient of friction (COF) of the coatings, did not show any correlation with the amount of silver, while the amorphous carbon phases seems to reduce the COF. Finally, the phase distribution showed a relevant role in the silver ion release to the electrolyte, as a function of the silver nanoparticles surrounding. This distribution of phases creates nanogalvanic couples in the system that controls the silver ion release, depending on a:C or ZrCN phases, the oxidation of silver can be enhanced or retarded, respectively. The antibacterial effect of the system does not have a direct relation with the silver ion release. Even coatings with low silver ion release may possess antibacterial capabilities, if silver is highly agglomerated on the surface.Neste trabalho foram depositados revestimentos do sistema Zr-C-N-Ag, incorporando a prata como um agente antibactericida, em substratos de aço inoxidável 316L e silício (100), utlizando a técnica de pulverização catódica por magnetrão. Os revestimentos foram caraterizados no que concerne o seu comportamento tribológico e à corrosão, no sentido de compreender o seu potencial para serem utilizados em próteses ortopédicas. O zircónio foi selecionado por causa da sua biocompatibilidade e comportamento não tóxico. Ao conhecimento do autor, apesar do sistema ZrCN ter sido amplamente estudado, não existe na literatura qualquer referência à investigação deste sistema incorporando prata. Assim, a contribuição deste trabalho para o estado da arte dos revestimentos Zr-C-N com adições de outros elementos é: (i) Caraterização estrutural, incluindo a análise da composição fásica, baseada quer na identificação das fases cristalinas (difração de raios X e microscopia eletrónica de transmissão) e amorfas (espectroscopia Raman) quer na avaliação da composição química dos revestimentos, no maciço (microssonda eletrónica) e na superfície (espectroscopia de fotoeletrões de raios X). A morfologia dos revestimentos em superfície e secção transversal foi analisada por microscopia eletrónica de varrimento, pondo em evidência a influência dos parâmteros de deposição na rugosidade e compacidade dos revestimentos. (ii) De modo a otimizar a adesão e as propriedades mecânicas e eletroquímicas dos revestimentos, um método de otimização foi aplicado ao processo de deposição para diminuir o número total de experiências. (iii) A caraterização eletroquímica e tribológica dos revestimentos foi realizada numa solução salina balanceada com 10 gr/L de albumina sérica bovina de modo a mimetizar as condições dos fluidos biológicos caraterísticos do corpo humano. Podem occorrer no Sistema Zr-C-N-Ag diversas fases, tais como os carbonitretos de zircónio (ZrCN), carbono amorfo (a-C or a-(C, N)) e prata metálica (Ag). Controlando as condições de deposição, é possível ajustar a quantidade de cada uma das fases e, então, alcançar as propriedades desejadas. A otimização do processo de deposição mostra que a composição ideal para os revestimentos de Zr-C-N-Ag é atingida quando é depositada a fase Zr2CN, com menos de 8 % at. de nanopartículas de prata, permitindo encontrar o melhor compromisso entre propriedades mecânicas, eletroquímicas e tribológicas. A caraterização eletroquímica permitiu concluir que ambas as fases de prata e de carbono amorfo são prejudiciais para a resistência à corrosão. Adicionalmente, a prata tem uma ação negativa na resistência ao desgaste do sistema, quando os testes são realizados contra um contracorpo de polietileno de alta densidade de elevado peso molecular, devido ao atraso que ela provoca na formação no contato da camada protetora de albumina. Finalmente, a distribuição de fases tem um papel relevante na libertação de iões de prata para o eletrólito, dependente da vizinhança que têm as nanopartículas de prata. Dependendo de haver a fase de carbono amorfo ou de ZrCN, a oxidação da prata pode ser, respetivamente, realçada ou retardada. O efeito antibactericida do sistema não tem uma relação direta com a libertação dos iões de prata. Mesmo revestimentos com libertação de iões de Ag reduzida podem possuir capacidades antimicrobianas, se houver suficiente teor de prata aglomerada na superfície.This thesis was financially supported by a PhD scholarship from Fundação para a Ciência e Tecnologia (Ref.: SFRH/BD/80947/2011), inserted in the Programa Potencial Humano Quadro de Referência Estratégico Nacional (POPH - QREN) Tipologia 4.1 – Formação Avançada. The POPH-QREN is co-financed by Fundo Social Europeu (FSE) and by Ministério da Ciência, Tecnologia e Ensino Superior (MCTES)

Análisis del patrocinio deportivo como herramienta de la comunicación corporativa del FC Barcelona en la temporada 2016/2017

En el presente trabajo de investigación analizaremos cómo influyen los patrocinadores del FC Barcelona en la comunicación corporativa del club, haciendo énfasis en términos o elementos como identidad, imagen, filosofía corporativa y posicionamiento, porque es importante saber que el patrocinado también obtiene efectos en su gestión empresarial por el hecho de mantener una relación a largo plazo con sus patrocinadores. De forma introductoria, empezaremos explicando el rango de acción del patrocinio (historia, conceptos, características, ventajas, objetivos) hasta adentrarnos al área deportiva donde nos enriqueceremos de cómo la acción de patrocinio se ha convertido en una herramienta indispensable y visible en la gran mayoría de las plataformas deportivas. Finalmente detallaremos la relación entre los patrocinadores y el FC Barcelona, donde el lector podrá saber quiénes son sus patrocinadores del club, que clase de patrocinios existe, los efectos de cada patrocinador en el club, etc. Para dichas conclusiones de nuestro análisis contaremos con diversas entrevistas a los mejores expertos en la materia de patrocinio deportivo. Esto nos permitirá obtener un mayor acercamiento y consolidación en nuestro objeto de estudio: el FC Barcelona

Ag+ release and corrosion behavior of zirconium carbonitride coatings with silver nanoparticles for biomedical devices

Zirconium carbonitride coatings with silver nanoparticles were produced by DC unbalanced dual magnetron sputtering system, using two targets, Zr and Zr/Ag in an Ar, C2H2 and N2 atmosphere. Stainless steel 316L and silicon (100) substrates were used for electrochemical and structural characterization, respectively. Silver was found to be well distributed throughout the coatings, maintaining the films' composition in depth, while its diffusion to the electrolyte decreases as immersion time increases, stopping its release after 7 to 8 days of immersion. Electrochemical characterization revealed very stable films that have improved base material, without any diminished corrosion resistance due to the silver content.The authors are grateful to 3B's Research Group in Biomaterials, Biodegradables and Biomimetics for the ICP measurements and Prof. Isabel Leonor, PhD for her assistance. This research is partially sponsored by FEDER funds through the program COMPETE-Programa Operacional Factores de Competitividade and by Portuguese national funds through FCT-Fundacao para a Ciencia e a Tecnologia, under the project ANTIMICROBCOAT-PTDC/CTM/102853/2008. This work has also been supported by the Ministerio de Ciencia e Innovacion of Spain through the Consolider-Ingenio 2010 program (CSD2008-00023) and through the project RyC2007-0026

Effects of multi-point contacts during object contour scanning using a biologically-inspired tactile sensor

Vibrissae are an important tactile sense organ of many mammals, in particular rodents like rats and mice. For instance, these animals use them in order to detect different object features, e.g., object-distances and -shapes. In engineering, vibrissae have long been established as a natural paragon for developing tactile sensors. So far, having object shape scanning and reconstruction in mind, almost all mechanical vibrissa models are restricted to contact scenarios with a single discrete contact force. Here, we deal with the effect of multi-point contacts in a specific scanning scenario, where an artificial vibrissa is swept along partly concave object contours. The vibrissa is modeled as a cylindrical, one-sided clamped Euler-Bernoulli bending rod undergoing large deflections. The elasticae and the support reactions during scanning are theoretically calculated and measured in experiments, using a spring steel wire, attached to a force/torque-sensor. The experiments validate the simulation results and show that the assumption of a quasi-static scanning displacement is a satisfying approach. Beyond single- and two-point contacts, a distinction is made between tip and tangential contacts. It is shown that, in theory, these contact phases can be identified solely based on the support reactions, what is new in literature. In this way, multipoint contacts are reliably detected and filtered in order to discard incorrectly reconstructed contact points

Ferroelectric domain nucleation and switching pathways in hafnium oxide

Nanoscale ferroelectrics that can be integrated into microelectronic fabrication processes are highly desirable for low-power computing and non-volatile memory devices. However, scalable novel ferroelectric materials, such as hafnium oxide (HfO2), remain in a state of development, and a clear understanding of the effects of relevant compositional and processing parameters to control their ferroelectric properties and the actual polarization switching mechanisms are still under investigation. One key fundamental knowledge gap is the polarization switching pathway in ferroelectric hafnia. To further our fundamental understanding of domain nucleation and switching, we have studied polarization switching pathways in HfO2-x thin films in real-time at the atomic scale using transmission electron microscopy. We employed differential phase contrast imaging that allows for the acquisition of both hafnium and oxygen atomic column signals and facilitates the observation of relative movement of atomic columns between both sublattices. Our results demonstrate that the switching pathway involves a transient tetragonal-like local structure, as oxygen ions shift in locations and remain within their parent hafnium polyhedra

Nano-galvanic coupling for enhanced Ag+ release in ZrCN-Ag films: antibacterial application

The antibacterial properties of materials developed for medical devices with embedded silver nanoparticles are enhanced by controlling the release of silver ions. In this study, a simple experimental procedure for the augmentation of the silver ion release from ZrCN-Ag coatings is described. The silver nanoparticles are embedded in an amorphous carbon matrix within the ZrCN coatings, to create nano-galvanic couples between the silver and the carbon phases. The galvanic couple promotes the oxidation of silver, and consequently, increases the silver release. It is demonstrated that coatings with a lower silver content, but integrating amorphous carbon phases, can release similar or even a larger amount of Ag+ ions than those with higher Ag content having just ZrCN and Ag phases. The antibacterial tests demonstrate that coatings with silver nanoparticles encapsulated into amorphous phase reveal a larger bacterial zone of inhibition compared to samples with similar or lower silver content. However, it is shown that the antibacterial effect of the coatings not only depends on the ability for silver ion release, but also on the availability of silver nanoparticles on the surface.This research is partially sponsored by FEDER funds through the program COMPETE - Programa Operacional Factores de Competitividade and by Portuguese national funds through FCT-Fundacao para a Ciencia e a Tecnologia, under the projects ANTIMICROBCOAT - PTDC/CTM/102853/2008 and in the framework of the Strategic Projects PEST-C/ FIS/UI607/2011", UID/EMS/00285/2013 and SFRH/BD/80947/2011

Surface characterization of Ti-Si-C-ON coatings for orthopedic devices : XPS and Raman spectroscopy

Ti–Si–C–ON films were deposited by DC reactive magnetron sputtering and their chemical properties, biofilm formation and toxicity were characterized. Based on the films composition three different growth regimes were identified on the films; (I) N/Ti = 2.11 (high atomic ratio) and low oxygen content; (II) 0.77 ≤ N/Ti ≤ 1.86 (intermediate atomic ratio) and (III) N/Ti ≤ 0.12 (low ratio) and high oxygen content. The phase composition varied from mainly TiN on regime I to TiCN on regime 2 and titanium oxides on regime III. Taking into account the results of biological characterization (biofilm formation and cytotoxicity), it was possible to conclude that samples with a high TiN content (regime I) presented more favorable biocompatibility, since it was less prone to microbial colonization and also displayed a low cytotoxicity.The authors are grateful to Dr. Alicia Andres, Institut de Ciencia de Materiales de Madrid (ICMM-CSIC), for his assistance in carrying out the Raman spectroscopic analysis. The work was financially supported by the CRUP Institution (project "Accao No E-1007/08), and the Spanish Ministry of Science and Innovation (projects FUN-COAT CSD2008-00023, MAT2008-06618-C02 and Integrated action HP016-2007). This research is partially sponsored by FEDER funds through the program COMPETE- Programa Operacional Factores de Competitividade and by Portuguese national funds through FCT-Fundacao para a Ciencia e a Tecnologia, under the project PTDC/CTM/102853/2008

3D Virtual Environment of the periodic table as a support in the education of chemistry

Este artículo plantea el desarrollo de un entorno virtual de la tabla periódica con el propósito de adquirir una herramienta que apoye el aprendizaje de la química, usando técnicas de realidad virtual. Para el desarrollo de esta propuesta, primero, se realizó la caracterización de los diferentes conceptos de la tabla periódica y lo concerniente a Realidad Virtual; luego,  se diseñaron los componentes de la arquitectura, se modeló la base de datos y se realizaron los mockups; a partir de esto, se implementó el prototipo de la tabla periódica a través de técnicas de realidad virtual y modelado 3D y finalmente, se validaron los resultados del entorno virtual mediante un grupo de control de estudiantes de la materia química orgánica del Politécnico Jaime Isaza Cadavid, Profesores y personas externas y se hizo la retroalimentación del entorno, con base en la encuestas realizadas.This paper proposes the development of a virtual environment of periodic table to acquire a tool as a support the learning of chemistry, using virtual reality techniques. first, the characterization of the different concepts of the periodic table and that concerning Virtual Reality was carried out, then, the architecture components were designed, the database was modeled and the mockups were made, from this, the prototype of the periodic table was implemented through virtual reality techniques and 3D modeling and finally, through a control group of students rolled in organic chemistry course in Politecnico Jaime Isaza Cadavid, teachers, and other people the results of the virtual environment were validated , after that, the feedback was made based on the surveysThis paper proposes the development of a virtual environment of periodic table to acquire a tool as a support the learning of chemistry, using virtual reality techniques. first, the characterization of the different concepts of the periodic table and that concerning Virtual Reality was carried out, then, the architecture components were designed, the database was modeled and the mockups were made, from this, the prototype of the periodic table was implemented through virtual reality techniques and 3D modeling and finally, through a control group of students rolled in organic chemistry course in Politecnico Jaime Isaza Cadavid, teachers, and other people the results of the virtual environment were validated , after that, the feedback was made based on the surveys.Este artículo plantea el desarrollo de un entorno virtual de la tabla periódica con el propósito de adquirir una herramienta que apoye el aprendizaje de la química, usando técnicas de realidad virtual. Para el desarrollo de esta propuesta, primero, se realizó la caracterización de los diferentes conceptos de la tabla periódica y lo concerniente a Realidad Virtual; luego, se diseñaron los componentes de la arquitectura, se modeló la base de datos y se realizaron los mockups; a partir de esto, se implementó el prototipo de la tabla periódica a través de técnicas de realidad virtual y modelado 3D y finalmente, se validaron los resultados del entorno virtual mediante un grupo de control de estudiantes de la materia química orgánica del Politécnico Jaime Isaza Cadavid, profesores y personas externas y se hizo la retroalimentación del entorno, con base en la encuestas realizadas

Structure-property relations in ZrCN coatings for tribologic applications

ZrCN coatings were deposited by dc reactive magnetron sputtering with N2 flows ranging from 2 to 10 sccm in order to investigate the influence of the nitrogen incorporation on structure and properties. Information about the chemical composition was obtained by glow discharge optical emission spectroscopy and Rutherford backscattering spectroscopy. The evolution of the crystal structure studied by X-ray diffraction revealed the formation of a face-centred cubic ZrCN phase for N2 flows greater than 4 sccm. Additionally, the presence of an amorphous phase in the coatings deposited with the highest N2 flows could be evidenced by Raman spectroscopy and X-ray photoelectron spectroscopy. This phase can act as a lubricant resulting in a low coefficient of friction as shown in the conducted ball-on-disc tests. Nanoindentation measurements showed that coatings deposited with a 6 sccm N2 flow had the maximum hardness which also revealed the best performance in the conducted dry cutting tests.CRUP InstitutionSpanish Ministry of Science and InnovationChristian Doppler Research Associatio