Bücher von Ranganatha S

In this contribution, it is tried sketch different types of thin film fabrication technologies in general. Technological details of fabrication of thin films employing electroless method are discussed in detail, with their principles. Also, the analytical methods to characterize the deposited think films are presented here. In this view, this collection is very significant for the researchers who are interested in designing thin films aiming for specific applications.

In this contribution, it is tried sketch different types of thin film fabrication technologies in general. Technological details of fabrication of thin films employing electroless method are discussed in detail, with their principles. Also, the analytical methods to characterize the deposited think films are presented here. In this view, this collection is very significant for the researchers who are interested in designing thin films aiming for specific applications.

In this contribution, it is tried sketch different types of thin film fabrication technologies in general. Technological details of fabrication of thin films employing electroless method are discussed in detail, with their principles. Also, the analytical methods to characterize the deposited think films are presented here. In this view, this collection is very significant for the researchers who are interested in designing thin films aiming for specific applications.

In this contribution, it is tried sketch different types of thin film fabrication technologies in general. Technological details of fabrication of thin films employing electroless method are discussed in detail, with their principles. Also, the analytical methods to characterize the deposited think films are presented here. In this view, this collection is very significant for the researchers who are interested in designing thin films aiming for specific applications.

Corrosion inhibitors are the chemically active molecules which on adsorption protect the thin films or substrate materials from corrosion. The corrosion protection efficiency of the molecules adsorbed, can be studied by adopting several experimental procedures. Conventionally followed and most reliable technique is weight loss method. The instrumental techniques include, Potentiodynamic polarization or Tafel plots, Electrochemical impedance spectroscopy and Chronoamperometry. The theoretical technique which stands extraordinary is Quantum mechanical methods which involves the theoretical approach to evaluate the efficiency of the molecules in required application. In this chapter, principles of all the above techniques are discussed in detail with experimental procedures.

The development in human life style and society implicating depletion of natural resources which are non-renewable because of drastic demand in energy. There are many simultaneous consequences like increased global temperature, pollution w.r,t. air, water and others. Adding to this, improved living standards of ours demands immediate requirement for efficient devices for electrical energy conversion and storage. The popular means for this are electrochemical supercapacitor, batteries for the purpose of storage and solar cells for conversion of electrical energy.

Lo sviluppo dello stile di vita e della società umana comporta l'esaurimento delle risorse naturali non rinnovabili a causa della drastica richiesta di energia. Vi sono molte conseguenze simultanee, come l'aumento della temperatura globale, l'inquinamento dell'aria e dell'acqua e altre ancora. Inoltre, il miglioramento del nostro tenore di vita richiede la necessità immediata di dispositivi efficienti per la conversione e l'immagazzinamento dell'energia elettrica. I mezzi più diffusi sono i supercondensatori elettrochimici, le batterie per lo stoccaggio e le celle solari per la conversione dell'energia elettrica.

O desenvolvimento do estilo de vida humano e da sociedade que implica o esgotamento dos recursos naturais não renováveis devido à drástica procura de energia. Há muitas consequências simultâneas como o aumento da temperatura global, poluição w.r,t. ar, água e outros. Para além disso, a melhoria do nosso nível de vida exige a necessidade imediata de dispositivos eficientes para a conversão e armazenamento de energia eléctrica. Os meios populares para tal são o supercapacitor electroquímico, baterias para efeitos de armazenamento e células solares para conversão de energia eléctrica.

L'évolution du mode de vie et de la société implique l'épuisement des ressources naturelles non renouvelables en raison de la demande drastique d'énergie. Il y a de nombreuses conséquences simultanées telles que l'augmentation de la température globale, la pollution de l'air, de l'eau et autres. En outre, l'amélioration de notre niveau de vie exige la mise en place immédiate de dispositifs efficaces pour la conversion et le stockage de l'énergie électrique. Les moyens les plus courants sont les supercondensateurs électrochimiques, les batteries pour le stockage et les cellules solaires pour la conversion de l'énergie électrique.

Die Entwicklung des menschlichen Lebensstils und der Gesellschaft hat die Erschöpfung der natürlichen Ressourcen zur Folge, die aufgrund des drastischen Energiebedarfs nicht erneuerbar sind. Es gibt viele gleichzeitige Folgen wie erhöhte globale Temperatur, Verschmutzung von Luft und Wasser und andere. Hinzu kommt, dass unser verbesserter Lebensstandard einen unmittelbaren Bedarf an effizienten Geräten zur Umwandlung und Speicherung elektrischer Energie erfordert. Die beliebtesten Mittel hierfür sind elektrochemische Superkondensatoren, Batterien für die Speicherung und Solarzellen für die Umwandlung elektrischer Energie.

El desarrollo del estilo de vida humano y de la sociedad implica el agotamiento de los recursos naturales no renovables debido a la drástica demanda de energía. Hay muchas consecuencias simultáneas como el aumento de la temperatura global, la contaminación del aire, el agua y otros. Además, la mejora de nuestro nivel de vida exige dispositivos eficaces para la conversión y el almacenamiento de la energía eléctrica. Los medios más utilizados para ello son los supercondensadores electroquímicos, las baterías para el almacenamiento y las células solares para la conversión de la energía eléctrica.

Razwitie chelowecheskogo obraza zhizni i obschestwa priwodit k istoscheniü prirodnyh resursow, kotorye newozobnowlqemy, iz-za rezkogo sprosa na änergiü. Suschestwuet mnozhestwo odnowremennyh posledstwij, takih kak powyshenie global'noj temperatury, zagrqznenie wozduha, wody i drugih. Krome togo, powyshenie urownq zhizni trebuet nemedlennogo sozdaniq äffektiwnyh ustrojstw dlq preobrazowaniq i hraneniq älektricheskoj änergii. Populqrnymi sredstwami dlq ätogo qwlqütsq älektrohimicheskie superkondensatory, batarei dlq hraneniq i solnechnye batarei dlq preobrazowaniq älektricheskoj änergii.

A liga Ni-W-P ternária electroless e as suas películas compostas MoS2 foram obtidas com sucesso em aço de baixo carbono pela técnica de galvanização electroless. A concentração de tungstato de sódio no banho foi variada para obter depósitos de Ni-W-P contendo vários teores de W e P. O compósito Ni-W-P-MoS2 foi obtido com uma concentração adequada de tungstato de sódio no banho de galvanização. Estes depósitos foram caracterizados por difracção de raios X (DRX), microscopia electrónica de varrimento e estudos espectroscópicos de DRX dispersivo de energia. O comportamento da corrosão foi investigado através de estudos de polarização potenciodinâmica e espectroscopia de impedância electroquímica numa solução de NaCl 3,5 wt%. Um aumento na codeposição da liga de tungsténio metálico alterou a estrutura e morfologia dos depósitos e aumentou a resistência à corrosão. Foram avaliadas propriedades mecânicas tais como microdureza e coeficientes de fricção. Verificou-se que os depósitos de Ni-W-P com quantidades crescentes de tungsténio metálico possuíam coeficientes de fricção mais elevados. A microdureza foi muito melhorada com o aumento da codeposição do metal de tungsténio na liga.

La lega ternaria Ni-W-P e i suoi film compositi di MoS2 sono stati ottenuti con successo su acciaio a basso tenore di carbonio mediante la tecnica della placcatura elettrolitica. La concentrazione di tungstato di sodio nel bagno è stata variata per ottenere depositi di Ni-W-P contenenti vari contenuti di W e P. Il composito Ni-W-P-MoS2 è stato ottenuto con un'adeguata concentrazione di tungstato di sodio nel bagno di placcatura. Questi depositi sono stati caratterizzati mediante diffrazione di raggi X (XRD), microscopia elettronica a scansione e studi di spettroscopia XRD a dispersione di energia. Il comportamento alla corrosione è stato studiato mediante polarizzazione potenziodinamica e spettroscopia di impedenza elettrochimica in una soluzione di NaCl al 3,5% in peso. Un aumento della codeposizione del metallo di lega tungsteno ha modificato la struttura e la morfologia dei depositi e ha migliorato la resistenza alla corrosione. Sono state valutate le proprietà meccaniche, come la microdurezza e i coefficienti di attrito. I depositi Ni-W-P con quantità crescenti di tungsteno metallico sono risultati avere coefficienti di attrito più elevati. La microdurezza è stata notevolmente migliorata con l'aumento della codeposizione di tungsteno metallico nella lega.

L'alliage ternaire Ni-W-P et ses films composites MoS2 ont été obtenus avec succès sur de l'acier à faible teneur en carbone par la technique de dépôt chimique. La concentration de tungstate de sodium dans le bain a été modifiée pour obtenir des dépôts de Ni-W-P contenant différentes teneurs en W et P. Le composite Ni-W-P-MoS2 a été obtenu avec une concentration appropriée de tungstate de sodium dans le bain de placage. Ces dépôts ont été caractérisés par diffraction des rayons X (XRD), microscopie électronique à balayage et spectroscopie XRD à dispersion d'énergie. Le comportement à la corrosion a été étudié par polarisation potentiodynamique et spectroscopie d'impédance électrochimique dans une solution de NaCl à 3,5 % en poids. Une augmentation de la codéposition du métal d'alliage tungstène a modifié la structure et la morphologie des dépôts et a amélioré la résistance à la corrosion. Les propriétés mécaniques telles que la microdureté et les coefficients de frottement ont été évaluées. Les dépôts de Ni-W-P contenant des quantités croissantes de tungstène se sont avérés posséder des coefficients de frottement plus élevés. La microdureté s'est considérablement améliorée avec l'augmentation de la codéposition de tungstène métallique dans l'alliage.

La aleación ternaria Ni-W-P y sus películas compuestas de MoS2 se obtuvieron con éxito sobre acero de bajo contenido en carbono mediante la técnica de electrodeposición. Se varió la concentración de tungstato sódico en el baño para obtener depósitos de Ni-W-P con diversos contenidos de W y P. El compuesto Ni-W-P-MoS2 se obtuvo con una concentración adecuada de tungstato sódico en el baño de revestimiento. Estos depósitos se caracterizaron mediante difracción de rayos X (DRX), microscopía electrónica de barrido y espectroscopía de DRX de energía dispersiva. El comportamiento frente a la corrosión se investigó mediante polarización potenciodinámica y espectroscopia de impedancia electroquímica en una solución de NaCl al 3,5% en peso. El aumento de la codeposición del metal de aleación wolframio modificó la estructura y la morfología de los depósitos y mejoró la resistencia a la corrosión. Se evaluaron propiedades mecánicas como la microdureza y los coeficientes de fricción. Se observó que los depósitos de Ni-W-P con cantidades crecientes de metal de tungsteno poseían coeficientes de fricción más elevados. La microdureza mejoró considerablemente con el aumento de la codeposición de metal de wolframio en la aleación.

Die stromlose ternäre Ni-W-P-Legierung und ihre MoS2-Verbundschichten wurden erfolgreich auf kohlenstoffarmen Stahl durch stromlose Beschichtungstechnik erhalten. Die Natriumwolframatkonzentration im Bad wurde variiert, um Ni-W-P-Ablagerungen mit verschiedenen W- und P-Gehalten zu erhalten. Ni-W-P-MoS2-Verbundwerkstoffe wurden mit einer geeigneten Konzentration von Natriumwolframat im Beschichtungsbad erhalten. Diese Ablagerungen wurden mittels Röntgenbeugung (XRD), Rasterelektronenmikroskopie und energiedispersiver XRD-Spektroskopie charakterisiert. Das Korrosionsverhalten wurde mittels potentiodynamischer Polarisation und elektrochemischer Impedanzspektroskopie in einer 3,5 Gew.-%igen NaCl-Lösung untersucht. Eine Erhöhung der Mitabscheidung des Legierungsmetalls Wolfram veränderte die Struktur und Morphologie der Ablagerungen und verbesserte die Korrosionsbeständigkeit. Mechanische Eigenschaften wie Mikrohärte und Reibungskoeffizienten wurden bewertet. Es wurde festgestellt, dass Ni-W-P-Schichten mit zunehmendem Wolframanteil höhere Reibungskoeffizienten aufweisen. Die Mikrohärte wurde mit zunehmender Mitabscheidung von Wolframmetall in der Legierung stark verbessert.

Metodom älektroosazhdeniq na nizkouglerodistoj stali byli uspeshno polucheny trojnoj splaw Ni-W-P i ego kompozitnye plenki MoS2. Koncentraciq tungstata natriq w wanne war'irowalas' dlq polucheniq osadkow Ni-W-P s razlichnym soderzhaniem W i P. Kompozit Ni-W-P-MoS2 byl poluchen pri podhodqschej koncentracii tungstata natriq w gal'wanicheskoj wanne. Jeti osadki byli oharakterizowany s pomosch'ü rentgenowskoj difrakcii (XRD), skaniruüschej älektronnoj mikroskopii i änergodispersionnoj XRD-spektroskopii. Korrozionnoe powedenie bylo issledowano s pomosch'ü potenciodinamicheskoj polqrizacii i älektrohimicheskoj impedansnoj spektroskopii w rastwore NaCl 3,5 wesowyh procentow. Uwelichenie kolichestwa osazhdeniq legiruüschego metalla wol'frama izmenilo strukturu i morfologiü osadkow i powysilo korrozionnuü stojkost'. Oceniwalis' mehanicheskie swojstwa, takie kak mikrotwerdost' i koäfficienty treniq. Bylo obnaruzheno, chto osadki Ni-W-P s uwelicheniem kolichestwa wol'frama obladaüt bolee wysokimi koäfficientami treniq. Mikrotwerdost' znachitel'no uluchshalas' s uwelicheniem soderzhaniq wol'frama w splawe.

Corrosion is a phenomenon in which metal is degraded when it is exposed to the environment. This deterioration of the metal leads to many impacts such as structure damage and material failure, leakage, environmental contamination, economic loss etc. This has made to find the solution so as to protect the material and corrosion inhibitor is one among several corrosion control strategies. These are typically molecules which adsorb onto the surface of the substrate and avoid its interaction with the environment thereby inhibiting the corrosion. These inhibitors are applied in many systems such as heat exchangers, storage tanks, boilers, cooling towers, pipes etc. Chromate being such a type of inhibitor is discriminated due to its non-environmentally friendly nature. Instead, scientific community is in search of highly performing green inhibitors for mostly employed industrially important steel materials. Curcumin and its derivatives satisfy this primary criterion along with the added advantages like economical, easy to obtain and hazardous free quality.

The electroless Ni¿W¿P ternary alloy and its MoS2 composite films were successfully obtained on low-carbon steel by the electroless plating technique. The sodium tungstate concentration in the bath was varied to obtain Ni¿W¿P deposits containing various W and P contents. Ni¿W¿P¿MoS2 composite was obtained with a suitable concentration of sodium tungstate in the plating bath. These deposits were characterized via x-ray diffraction (XRD), scanning electron microscopy and energy dispersive XRD spectroscopy studies. The corrosion behavior was investigated via potentiodynamic polarization and electrochemical impedance spectroscopy studies in a 3.5 wt% NaCl solution. An increase in codeposition of the alloying metal tungsten changed the structure and morphology of the deposits and enhanced the corrosion resistance. Mechanical properties such as microhardness and friction coefficients were evaluated. Ni¿W¿P deposits with increasing amounts of tungsten metal were found to possess higher friction coefficients. The microhardness was greatly improved with increasing codeposition of tungsten metal in the alloy.