187 research outputs found
The effects of deposition parameters on surface morphology and crystallographic orientation of electroless Ni-B coatings
No full textElectroless Ni-B coatings were deposited on AISI 304 stainless steels by electroless deposition method, which was performed for nine different test conditions at various levels of temperature, concentration of NaBH(4), concentration of NiCl(2), and time, using the Taguchi L(9)(3(4)) experimental method. The effects of deposition parameters on the crystallographic orientation of electroless Ni-B coatings were investigated using SEM and XRD equipment. SEM analysis revealed that the Ni-B coatings developed six types (pea-like, maize-like, primary nodular, blackberry-like or grapes-like, broccoli-like, and cauliflower-like) of morphological structures depending on the deposition parameters. XRD results also showed that these structures exhibited different levels of amorphous character. The concentration of NaBH(4) had the most dominant effect on the morphological and crystallographic development of electroless Ni-B coatings
Synergistic effect of bias and target currents for magnetron sputtered MoS2-Ti composite films
No full textIn terms of modification of the properties of MoS2-Ti composite films, especially tribological properties, significant advances have recently been recorded. However, the commercially production of MoS2-Ti composite films is still limited, because the production of desirable MoS2-Ti composite coating is only possible by using closed field unbalanced magnetron systems and by the selection of convenient deposition parameters. This requirement has focused the researchers' attention on optimization of deposition parameters. This study is concentrating on the effect of the bias voltage and the target currents for MoS2-Ti composite films deposited by pulsed magnetron sputtering (PMS). It is found that the bias and the target currents clearly affect the mechanical, structural and tribological properties of MoS2-Ti films
Pulsed-dc bias magnetron sputtered TiB2 ceramic coating
No full textTitanium diboride, TiB2, is well known as a ceramic material with a hexagonal structure which presents various attractive properties, such as high hardness and excellent corrosion, thermal oxidation, and wear resistance. However, one drawback of TiB2 coatings is their poor adhesion to substrate materials due to high compressive residual stress after deposition. The present study aimed to assess whether a PVD-TiB2 coating with both high hardness and sufficiently good adhesion to the substrate and good wear properties can be developed by a closed-field unbalanced magnetron sputtering system using pulsed-dc biasing. The TiB2 coating deposited on AISI M2 steel substrates was characterized in terms of the structural, mechanical and tribological property. From the experimental results, it can be concluded that a closed-field unbalanced magnetron sputtering system using pulsed-dc biasing can be used to produce a TiB2 coating with sufficiently good adhesion (82 N), and high hardness (2300 HK0.01), and low friction (0.34) under given deposition conditions. The deposition conditions, particularly substrate biasing and rotation, which inhibited the formation of (001) orientation, played a role in the coating's lack of superhardness
Characterization of Ti-CN-a:C films prepared by pulsed-dc bias sputtering
No full textThe incapable side of diamond-like carbon films is low adhesion, resulting from high internal stress. The incorporation of buffer layers into the coating structure to relieve stress and to allow crack energy dissipation by plastic deformation in the crack tip is an effective route for improving toughness. Although this approach will result in a partly decreased coating hardness, the gain in tribological properties is more preferred for many applications. In graded coatings, design and joining of the functional regions including sharp interfaces between layers are very important. The desirable properties can provide only through appropriate transition regions produced by using appropriate deposition methods. In this study, Ti-CN-a:C films were deposited on AISI M2 steel substrates by closed-field unbalanced magnetron sputtering using pulsed-dc biasing, and hardness, crystallography, wear, and adhesion properties of the film were investigated. Accordingly, Ti-CN-a: C films grown exhibited an increase of about 30 per cent in hardness according to that of the substrate and low (mu similar to 0.1) and stable friction and good adhesion (L-c = 43 N), whereas the crystallographic development of the film was amorphous. These properties obtained were attributed to using of CN transient layer and pulsed-dc magnetron sputtering technology
STRESS-RELIEF SOLUTIONS FOR BRITTLE TiB2 COATINGS
No full textEngineering applications of TiB2 coatings are limited because of the brittle nature of interfacial bonds on the substrate surfaces, although they have many major properties such as high hardness, high wear and high temperature strength. To overcome this drawback, many researchers have studied over many years and their efforts have taken several forms such as the rotation of substrate, heating treatment during deposition or after deposition, application of positive bias voltage to the substrate, the introduction of transition elements as an interlayer, gradient or multilayer or composite strengthening, and the optimization studies performed by changing deposition process types and/or process parameters such as working gas and bias voltage. The purpose of this paper is to discuss these solutions proposed or developed by researchers against the limited use of TiB2 coatings due to its brittleness and low adhesion. From the results reported in literature, it is concluded that the best solution in order to produce non-brittle TiB2 based film well adherent to substrate is the use of pulsed-dc deposition technology provided that the process parameters are tuned to give an appropriate composition and/or a coating design. Furthermore, the TiB2 based coatings with multiphase layers seem to give better results respect to adherence
Effect of crystallographic orientation on the friction and wear properties of MoxSy-Ti coatings by pulsed-dc in nitrogen and humid air
No full textThis work reports on the structural and wear properties of MoxSy-Ti films, deposited on D2, 52100, and 440C steel substrates by pulsed-dc magnetron sputtering. A closed field unbalanced magnetron sputter ion plating system was used for the deposition process. The mechanical and tribological properties of MoxSy-Ti coated composites onto selected steel substrates were characterized using microhardness test, friction-wear test in atmospheric conditions and in dry nitrogen. The X-ray diffraction (XRD) was used to determine the phase structure. Structural analysis was performed using SEM-EDS. MoxSy-Ti films showed a very dense structure with pronounced basal plane (0 0 2) orientation, which showed the lowest friction coefficient (0.022) in dry nitrogen. The coefficient of friction can be attributed to the oxidation of MoS2 at the wear track to form MoOx that is known to cause an increase in the friction coefficient. In humid air, an oxidative environment, the films had higher coefficient of friction (0.07). and lower wear life (142 500 passes with 2.11 x 10(-6) mm(3)/N m wear rate) than in dry nitrogen, where the wear life was over 250000 passes with the lowest wear rate of 3 x 10(-8) mm(3)/N m. (C) 2004 Published by Elsevier B.V
Fabrication of antibacterial and hydrophilic electroless Ni-B coating on 316L stainless steel
No full textBiomaterial-associated bacterial infection is one of the most common complications with medical vehicles and implants made of stainless steel. A surface coating treatment like electroless Ni-B deposition, a new candidate to be used in a broad range of engineering applications owing to many advantages such as low cost, thickness uniformity, good wear resistance, may improve the antibacterial activity and physical properties of biomedical devices made of stainless steel. In this study, the antibacterial property of the electroless Ni-B film coated on AISI 316L (UNS S31603) stainless steel is basically investigated. Inhibition halo diameter measurement after incubation at 37 degrees C and 24 h demonstrates the existence of antimicrobial activity of the electroless Ni-B coating deposited on 316L stainless steel over the Escherichia coli test bacteria. The results of X-ray diffraction, scanning electron microscopy, atomic force microscopy and microhardness measurement studies confirms that the coating deposited on the substrate has an uniform amorphous and a harder structure. Besides, the wettability property of the uncoated substrate and the coating was measured as the contact angle of water. The water contact angle reduced about from 97.7 to 69.25 degrees
Análisis comparativo de dos historias de amor: los amantes de Teruel y Ferhat i̇le Şi̇ri̇n de la tradicion oral a la literatura
No full textLa presente tesis doctoral es un estudio comparativo de dos leyendas de distintas culturas: «Los Amantes de Teruel» de España y «Ferhat ile Şirin» de Turquía. Es el primer estudio que contiene el análisis de una leyenda española con un relato turco desde un punto de vista comparativo utilizando una bibliografía amplia de los importantes estudiosos de España, Turquía y de todo el mundo.
El estudio consta de dos partes. La primera parte contiene el análisis de los dos relatos en la tradición oral. En el primer capítulo se analiza la distinción entre los géneros folclóricos que pertenecen las dos historias: la leyenda y halk hikayesi. En el segundo capítulo se centran en los orígenes de «Los Amantes de Teruel» y su evolución en la cultura oral del país, analizando la estructura y los motivos folclóricos que contiene el primer testimonio oral del relato en España, el papel escrito de letra antigua de Yagüe de Salas. En el tercer capítulo se dedica a los orígenes del relato turco y al análisis comparativo de sus cinco versiones en la tradición oral turca teniendo en cuenta la estructura que se proporciona por el investigador turco del folclore, Pertev Naili Boratav y los motivos folclóricos de Antti Aarne. En el último capítulo de la primera parte se hace un análisis comparativo de la estructura y los motivos folclóricos de los primeros testimonios de las historias española y turca.
La segunda parte consta de sus versiones más exitosos en la literatura de dos países: Los amantes de Teruel de Juan Eugenio Hartzenbusch y Ferhat ile Şirin de Nazım Hikmet. En el primer capítulo se dedica a la vida y la época de Hartzenbusch y la comparación de las dos versiones de la obra; una escrita en 1839, el primer manuscrito y la otra de 1849. Así se ve tanto la evolución de la leyenda en la literatura y también la evolución del drama y el dramaturgo en el siglo XIX. En el segundo capítulo consta de la vida y época de Nazım Hikmet que cultiva su obra dentro del movimiento realismo social y se considera como uno de los autores de la literatura turca más conocidos mundialmente. Para hacer el análisis, escogimos la primera publicación de Ferhat ile Şirin y lo comparamos con su versión en castellano Leyenda de amor, que se traduce bajo el dominio del mismo autor. Así se ven los cambios a la hora de traducir la obra a otro idioma. Tambien se ven la evolución de la leyenda dentro de la literatura.This present thesis contains a comparative study of two legends of different cultures: "The Lovers of Teruel" in Spain and "Ferhat and Şirin" in Turkey. It is the first study that elaborates the analysis of a Spanish legend with a Turkish story from a comparative point of view using a large bibliography of leading scholars from Spain, Turkey and the entire world.
The study consists of two parts. The first part contains the analysis of the two stories in the oral tradition. In the first chapter analyses the diferences between the folk genders that belong two stories: the legend and halk hikayesi. The second chapter focuses on the origins of "The Lovers of Teruel" and its evolution in the oral culture of the country, analyzing the structure and folk motifs taht contains the first oral testimony of the story in Spain taht is written by notarial Yagüe de Salas. The third chapter is dedicated to the origins of the Turkish story and the comparative analysis of the structure of Pertev Naili Boratav and folk motifs of Antti Aarne of the five versions in Turkish oral tradition. The last chapter contains the comparative analysis of the structure and the folk motifs of the first testimonies of the Spanish and Turkish stories.
The second part consists of its most successful versions in the literature of two countries: The Lovers of Teruel of Juan Eugenio Hartzenbusch and Ferhat ile Şirin of Nazım Hikmet. The first chapter is dedicated to the life and the century of Hartzenbusch and the comparison of the two versions of the book; one is written in 1839, the first manuscript and the other in 1849. Wıth thıs study we see the evolution of the legend in literature and also the evolution of the drama in the 19th century. The second chapter consists of the life and era of Nazım Hikmet who cultivated his work within the social realism movement and is regarded as one of the authors of Turkish literature more known ın world. We chose the first publication of Ferhat ile Şirin and compare it with the version in Spanish Legend of Love, translated under the control of the same author. So we compare the diferences between the original text and the translation one and also the evolution of the legend in literature
Análisis comparativo de dos historias de amor : los amantes de Teruel y Ferhat i̇le Şi̇ri̇n : de la tradición oral a la literatura
No full textLa presente tesis doctoral es un estudio comparativo de dos leyendas de distintas culturas: «Los Amantes de Teruel» de España y «Ferhat ile Şirin» de Turquía. Es el primer estudio que contiene el análisis de una leyenda española con un relato turco desde un punto de vista comparativo utilizando una bibliografía amplia de los importantes estudiosos de España, Turquía y de todo el mundo. El estudio consta de dos partes. La primera parte contiene el análisis de los dos relatos en la tradición oral. En el primer capítulo se analiza la distinción entre los géneros folclóricos que pertenecen las dos historias: la leyenda y halk hikayesi. En el segundo capítulo se centran en los orígenes de «Los Amantes de Teruel» y su evolución en la cultura oral del país, analizando la estructura y los motivos folclóricos que contiene el primer testimonio oral del relato en España, el papel escrito de letra antigua de Yagüe de Salas. En el tercer capítulo se dedica a los orígenes del relato turco y al análisis comparativo de sus cinco versiones en la tradición oral turca teniendo en cuenta la estructura que se proporciona por el investigador turco del folclore, Pertev Naili Boratav y los motivos folclóricos de Antti Aarne. En el último capítulo de la primera parte se hace un análisis comparativo de la estructura y los motivos folclóricos de los primeros testimonios de las historias española y turca. La segunda parte consta de sus versiones más exitosos en la literatura de dos países: Los amantes de Teruel de Juan Eugenio Hartzenbusch y Ferhat ile Şirin de Nazım Hikmet. En el primer capítulo se dedica a la vida y la época de Hartzenbusch y la comparación de las dos versiones de la obra; una escrita en 1839, el primer manuscrito y la otra de 1849. Así se ve tanto la evolución de la leyenda en la literatura y también la evolución del drama y el dramaturgo en el siglo XIX. En el segundo capítulo consta de la vida y época de Nazım Hikmet que cultiva su obra dentro del movimiento realismo social y se considera como uno de los autores de la literatura turca más conocidos mundialmente. Para hacer el análisis, escogimos la primera publicación de Ferhat ile Şirin y lo comparamos con su versión en castellano Leyenda de amor, que se traduce bajo el dominio del mismo autor. Así se ven los cambios a la hora de traducir la obra a otro idioma. Tambien se ven la evolución de la leyenda dentro de la literatura.This present thesis contains a comparative study of two legends of different cultures: "The Lovers of Teruel" in Spain and "Ferhat and Şirin" in Turkey. It is the first study that elaborates the analysis of a Spanish legend with a Turkish story from a comparative point of view using a large bibliography of leading scholars from Spain, Turkey and the entire world. The study consists of two parts. The first part contains the analysis of the two stories in the oral tradition. In the first chapter analyses the diferences between the folk genders that belong two stories: the legend and halk hikayesi. The second chapter focuses on the origins of "The Lovers of Teruel" and its evolution in the oral culture of the country, analyzing the structure and folk motifs taht contains the first oral testimony of the story in Spain taht is written by notarial Yagüe de Salas. The third chapter is dedicated to the origins of the Turkish story and the comparative analysis of the structure of Pertev Naili Boratav and folk motifs of Antti Aarne of the five versions in Turkish oral tradition. The last chapter contains the comparative analysis of the structure and the folk motifs of the first testimonies of the Spanish and Turkish stories. The second part consists of its most successful versions in the literature of two countries: The Lovers of Teruel of Juan Eugenio Hartzenbusch and Ferhat ile Şirin of Nazım Hikmet. The first chapter is dedicated to the life and the century of Hartzenbusch and the comparison of the two versions of the book; one is written in 1839, the first manuscript and the other in 1849. Wıth thıs study we see the evolution of the legend in literature and also the evolution of the drama in the 19th century. The second chapter consists of the life and era of Nazım Hikmet who cultivated his work within the social realism movement and is regarded as one of the authors of Turkish literature more known ın world. We chose the first publication of Ferhat ile Şirin and compare it with the version in Spanish Legend of Love, translated under the control of the same author. So we compare the diferences between the original text and the translation one and also the evolution of the legend in literature
Effects of Graphite Incorporation and Annealing on the Structural, Tribological, and Functional Properties of Electroless Ni-B Coatings
No full textThis study explores the synergistic effects of graphite nanoparticles (0.1 wt.%) and thermal annealing (100-600 degrees C) on electroless Ni-B coatings for AISI 4140 steel. Graphite-enabled multifunctional performance-crystallization control, friction reduction, and antibacterial activity-are unlike conventional Ni-B systems. XRD showed amorphous-to-crystalline (Ni3B/Ni2B) transformation, with graphite acting as a nucleation agent below 300 degrees C before degrading at 600 degrees C. The 300 degrees C-annealed composite achieved optimal properties: 0.2 friction coefficient (75% lower than uncoated steel), 60% higher wear resistance, and hardness of 777 HV (+ 3.6% over as-deposited), attributed to graphite lubrication and nanocrystalline Ni3B formation. Antibacterial tests revealed a 3.4-mm inhibition zone against E. coli, though efficacy declined at higher temperatures due to graphite oxidation. All composites maintained superhydrophilicity (contact angle approximate to 0 degrees) without mechanical compromise. By correlating annealing temperature with microstructure, this work provides a design framework for Ni-B/graphite coatings combining low friction (mu = 0.2), high hardness (785 HV), and antibacterial functionality-addressing critical needs for wear-resistant, hygienic surfaces in biomedical and industrial applications
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