This thesis was written for a Swedish valve manufacturer to find out in what temperature regimes it was possible to replace electroplated hard chromium with autocatalytic electroless nickel-phosphorus. In this work the dry sliding wear properties of electroplated hard chromium and autocatalytic electroless nickel-phosphorus(10% P) were compared. All tests and investigations were done by using available equipment at Karlstads University. The tests were made to find out how the wear of these coatings behaved at different temperatures, how different substrates influence the wear of these coatings and how the roughness of the substrate surface influence the wear properties of these coatings. The method used for the wear tests was block-on-ring with a counterformal contact mode. The tests were executed in room temperature, 300C and 400C; with a normal load of 100N, sliding speed was 150rpm and duration of the tests were 15 minutes. All tests were done in an argon gas atmosphere. The coatings was deposited onto the cylinders with a thickness of 30µm. The different substrates used were an austenitic stainless steel(1.4404) and an austenitic-ferritic(duplex) stainless steel(1.4460). Half of the austenitic cylinders had a machined surface and all the others(including duplex cylinders) were machined and grinded to achieve a smoother surface. The blocks used as countersurface were made out of austenitic-ferritic(duplex) stainless steel(1.4460). Equipment used to investigate the wear tracks were stereo microscopy, profilometer, microhardness tester and scanning electron microscopy(SEM). The coatings were investigated in matter such as wear depth, wear mode, wear mechanism, chemical composition, topography, morphology, cross-section and hardness. The results of this work showed that the nickel coating wear tracks maximal depth were less deep than those of hard chrome, at room temperature. At elevated temperatures the performance varies. The coatings deposited onto cylinders made out of duplex stainless steel performed better than those deposited onto austenitic cylinders. The nickel coating performed better deposited onto the substrates with smooth surface and the chrome coating performed better deposited onto the substrates with rough surface

Digital musical instruments pose a number of unique challenges for designers and performers. These issues stem primarily from the lack of innate physical connection between the performance interface and means of sound generation, for the latter is usually dematerialised. Thus, this relationship must instead be explicitly determined by the designer, and can be essentially any desired. However, many design issues and constraints remain poorly understood, from the nature of control to the provision of performer-instrument feedback. This practice-based research contends that while the digital and acoustic domains are so different as to be fundamentally incompatible, useful antecedents for digital musical instruments can be found in the histories of electronic music. Specifically, it argues that the live electronics of David Tudor are of particular prescience. His home-made circuits offer an electronic music paradigm quite antithetical to both the familiar keyboard interface and the electronic music studios that grew up in the years after World War II, and are seen to embody a number of aspirational qualities. These include performer-instrument interaction more akin to steering rather than fine control, the potential for musical outcomes that are unknown and unknowable in advance, and distinct instrumental character. This leads to the central contribution of this research; the development of a Tudor-inspired conceptual framework that can inform how digital musical instruments are designed, played, and evaluated. To enable more detailed and nuanced discussion, the framework is broken down into a series of sub-themes. These include both design issues such as nuance, plasticity and emergence, and human issues such as experience, expressiveness, skill, learning, and mastery. The notion of sketching in hardware and software is also developed in relation to the rapid iteration of multiple designs. Informed by this framework, seven new digital musical instruments are presented. These instruments are tested from two different perspectives, with the personal experiences of the author supplemented with data from a series of smallscale user studies. Particular emphasis is placed on how the instruments are played, the music they can produce, and their capacity to convey the musical intentions of the performer (i.e. their expressiveness). After the evaluation of the instruments, the Tudorian framework is revisited to form the basis of the conclusions. A number of modifications to the original framework are proposed, from the addition of a dialogical model of performerinstrument interaction, to the situation of digital musical instruments within a wider musical ecology. The thesis then closes with a suggestion of possibilities for future research.

The purpose of this study was to explore whether Indian counsellors and psychotherapists in the UK practice in an indigenous way with their Indian clients. The aim was to find out more information about the different types of Indian indigenous interventions that may currently be used by these professionals. The study also bridges the gap in the literature about the lack of research on the practical uses and applications of Indian indigenous counselling skills in the UK.The study reports data from six face-to-face open-ended semi-structured interviews with Indian counsellors who have been trained in Western psychotherapeutic approaches and have knowledge of Indian psychotherapeutic approaches. The research was analysed using Interpretative Phenomenological Analysis (IPA). Firstly, the analysis concluded the use of several Indian indigenous interventions used by the participants, such as Prekshadhyan which can be used for psychosomatic pain relief, Jain virtue of forgiveness which can be useful for working with sexual abuse, use of spirituality and cultural beliefs for bereavement, and so on. Secondly, the analysis identified some of the most common barriers to therapy (e.g. stigmas and taboos) experienced by Indian clients in the UK, and it provided suggestions on how to overcome these. Finally, the analysis suggested factors that therapists should pay attention to (e.g. client context and use of Indian languages) in order to maximise Indian clients’ engagement in therapy and to minimise their exclusion from it.

O revestimento de níquel químico é largamente utilizado na proteção contra a corrosão de equipamentos e estruturas utilizados na exploração de petróleo em águas profundas. Apesar de ser considerado um dos revestimentos mais adequados para esta finalidade, são muitos os casos em que se verificam falhas prematuras do revestimento em serviço. Isto tem sido atribuído às diferenças nas características do revestimento decorrentes das diferenças do processo de aplicação e da natureza e preparação da superfície dos substratos a serem protegidos. Estas diferenças decorrem do fato de não existirem especificações abrangentes que definam as características necessárias do revestimento para uma garantia de qualidade. Diante disto, o presente trabalho teve como objetivo estudar a influência dos principais fatores sobre o desempenho dos revestimentos de níquel químico utilizando ferramentas estatísticas como: planejamento fatorial, seleção dos melhores subconjuntos de regressão, regressão múltipla e curvas de nível. Os fatores considerados neste estudo foram: tipo e estado superficial do substrato, idade do banho, teor de fósforo no revestimento, natureza e teor de contaminantes no revestimento, espessura do revestimento e tipo de tratamento térmico. A caracterização dos revestimentos de níquel químico foi realizada conforme sugerida na norma ISO 4527 e o desempenho dos revestimentos foi verificado por meio dos ensaios de exposição à névoa salina (1 536 h), exposição ao dióxido de enxofre (10 ciclos) e imersão em água do mar sintética (120 dias). Ensaios eletroquímicos (polarização linear e espectroscopia de impedância eletroquímica) foram realizados somente com o intuito de compará-los ao ensaio de exposição à névoa salina e,assim, ter um ensaio capaz de verificar revestimentos de bom desempenho em um período de tempo menor. Dentro dos intervalos estudados, verificou-se que o desempenho do revestimento de níquel químico é influenciado pelo tipo de substrato, pela espessura da camada depositada, pelo teor de fósforo, pela idade do banho, pelo tratamento térmico e pelos teores dos seguintes contaminantes: enxofre, chumbo, magnésio, cobre, ferro e manganês. A metodologia estatística adotada permitiu verificar a interação entre os fatores influenciadores, fato não considerado na literatura consultada. Além disto, foi possível constatar que os ensaios adotados nas normas internacionais atuais são adequados para verificar a qualidade dos revestimentos. Verificou-se também que os ensaios eletroquímicos, apesar de adequados para o estudo da resistência intrínseca à corrosão do revestimento de níquel químico, não se mostraram adequados para detectar a presença de porosidade que é o principal indicativo da qualidade de proteção por barreira de revestimentos catódicos como o níquel químico. Com os resultados obtidos, será possível a elaboração de uma especificação para se obter revestimentos de níquel químico com bom desempenho. / The autocatalytic nickel-phosphorus (NiP) or electroless nickel (EN) coatings are widely used to protect equipment and structures against corrosion and erosion, used in the exploitation of petroleum in deep waters. Even though NiP is considered as the most appropriate coating for this purpose, many premature failures are verified in service. This has been attributed to the differences in the characteristics of the coating due to the differences in the application processes and in the nature and preparation of the substrate surfaces. The lack of broad specifications that define the required characteristics of the good quality coating is responsible for those differences. The present work had as its objective to identify the main factors related to the NiP performance using statistical tools as: factorial design, best subset regression, multiple regression and contour diagram. The considered factors were: substrate type, substrate surface finishing, bath age, phosphorus content, thickness, heat treatment and impurities. The NiP coatings were characterized in agreement with the ISO 4527 and their performance was verified through the salt spray test (1 536 h), the Kesternish test (10 cycles) and the synthetic sea water immersion test (120 days). Electrochemical tests (linear polarization and electrochemical impedance spectroscopy) were conducted in order to compare them to the salt spray test and thus reducing the testing time. In the studied range, it was verified that the NiP performance is influenced by the following factors: substrate type, thickness coating, phosphorus content, bath age (MTO), heat treatment and the impurities: sulfur, lead, magnesium, copper, iron and manganese. It was possible to verify that the types of accelerated corrosion tests adopted in the current international standards are appropriate to verify the quality of the coatings. It was also verified that the electrochemical tests, despite being suitable to indicate the NiP intrinsic corrosion resistance, are not appropriate to verify the NiP porosity (which is the main indication of a cathodic coating quality). With the obtained results, it will be possible to establish a better specification in order to obtain NiP with good quality.

O revestimento de níquel químico é largamente utilizado na proteção contra a corrosão de equipamentos e estruturas utilizados na exploração de petróleo em águas profundas. Apesar de ser considerado um dos revestimentos mais adequados para esta finalidade, são muitos os casos em que se verificam falhas prematuras do revestimento em serviço. Isto tem sido atribuído às diferenças nas características do revestimento decorrentes das diferenças do processo de aplicação e da natureza e preparação da superfície dos substratos a serem protegidos. Estas diferenças decorrem do fato de não existirem especificações abrangentes que definam as características necessárias do revestimento para uma garantia de qualidade. Diante disto, o presente trabalho teve como objetivo estudar a influência dos principais fatores sobre o desempenho dos revestimentos de níquel químico utilizando ferramentas estatísticas como: planejamento fatorial, seleção dos melhores subconjuntos de regressão, regressão múltipla e curvas de nível. Os fatores considerados neste estudo foram: tipo e estado superficial do substrato, idade do banho, teor de fósforo no revestimento, natureza e teor de contaminantes no revestimento, espessura do revestimento e tipo de tratamento térmico. A caracterização dos revestimentos de níquel químico foi realizada conforme sugerida na norma ISO 4527 e o desempenho dos revestimentos foi verificado por meio dos ensaios de exposição à névoa salina (1 536 h), exposição ao dióxido de enxofre (10 ciclos) e imersão em água do mar sintética (120 dias). Ensaios eletroquímicos (polarização linear e espectroscopia de impedância eletroquímica) foram realizados somente com o intuito de compará-los ao ensaio de exposição à névoa salina e,assim, ter um ensaio capaz de verificar revestimentos de bom desempenho em um período de tempo menor. Dentro dos intervalos estudados, verificou-se que o desempenho do revestimento de níquel químico é influenciado pelo tipo de substrato, pela espessura da camada depositada, pelo teor de fósforo, pela idade do banho, pelo tratamento térmico e pelos teores dos seguintes contaminantes: enxofre, chumbo, magnésio, cobre, ferro e manganês. A metodologia estatística adotada permitiu verificar a interação entre os fatores influenciadores, fato não considerado na literatura consultada. Além disto, foi possível constatar que os ensaios adotados nas normas internacionais atuais são adequados para verificar a qualidade dos revestimentos. Verificou-se também que os ensaios eletroquímicos, apesar de adequados para o estudo da resistência intrínseca à corrosão do revestimento de níquel químico, não se mostraram adequados para detectar a presença de porosidade que é o principal indicativo da qualidade de proteção por barreira de revestimentos catódicos como o níquel químico. Com os resultados obtidos, será possível a elaboração de uma especificação para se obter revestimentos de níquel químico com bom desempenho. / The autocatalytic nickel-phosphorus (NiP) or electroless nickel (EN) coatings are widely used to protect equipment and structures against corrosion and erosion, used in the exploitation of petroleum in deep waters. Even though NiP is considered as the most appropriate coating for this purpose, many premature failures are verified in service. This has been attributed to the differences in the characteristics of the coating due to the differences in the application processes and in the nature and preparation of the substrate surfaces. The lack of broad specifications that define the required characteristics of the good quality coating is responsible for those differences. The present work had as its objective to identify the main factors related to the NiP performance using statistical tools as: factorial design, best subset regression, multiple regression and contour diagram. The considered factors were: substrate type, substrate surface finishing, bath age, phosphorus content, thickness, heat treatment and impurities. The NiP coatings were characterized in agreement with the ISO 4527 and their performance was verified through the salt spray test (1 536 h), the Kesternish test (10 cycles) and the synthetic sea water immersion test (120 days). Electrochemical tests (linear polarization and electrochemical impedance spectroscopy) were conducted in order to compare them to the salt spray test and thus reducing the testing time. In the studied range, it was verified that the NiP performance is influenced by the following factors: substrate type, thickness coating, phosphorus content, bath age (MTO), heat treatment and the impurities: sulfur, lead, magnesium, copper, iron and manganese. It was possible to verify that the types of accelerated corrosion tests adopted in the current international standards are appropriate to verify the quality of the coatings. It was also verified that the electrochemical tests, despite being suitable to indicate the NiP intrinsic corrosion resistance, are not appropriate to verify the NiP porosity (which is the main indication of a cathodic coating quality). With the obtained results, it will be possible to establish a better specification in order to obtain NiP with good quality.

Hard anodising on aluminium and its alloys has been widely practised for many years in order to improve the resistance of the otherwise poor wear characteristics of aluminium. In recent years there has been an increasing interest in other treatments and coatings, on both aluminium and other base metals. The aim of this investigation is to explain the tribological performance and wear mechanism(s) of an uncoated aluminium alloy, four anodic coated alloys, and also an electroless nickel alloy. All of the coatings are produced on three different aluminium alloys. The thickness of the anodic films is 30-35 micron, as this thickness falls within the range commonly used by industry. In an endeavour to explain the role of coating thickness on wear life, electroless nickel alloy has been produced in a range of thicknesses of 10, 20 and 30 micron. To evaluate abrasive and adhesive wear, the samples were rubbed against a single point diamond and steel ball, respectively, in a reciprocating movement at room temperature and 65-75% relative humidity, under a wide range of load and sliding distance. Some tests continued to run until a breakdown of the coatings occurred, whilst other tests were interrupted at intermediate stages. This enabled the initiation and propagation of failure mechanisms to be studied. Abrasive wear was performed under dry conditions, whereas, adhesive wear was evaluated under both dry and lubricated conditions. Wear of these coatings was proportional to the applied load and sliding distance, but there was no direct relationship between wear and hardness. The tribological performance of these coatings appears to be dictated by a) the composition of the substrate, b) the chemical and physical nature of the coatings and c) the test conditions. Under boundary lubricated conditions there was a considerable increase in the wear life of the coatings. A three dimensional surface texture is superior to a machined surface, in controlling contact conditions. There is an approximate linear relationship between coating thickness and wear life for electroless nickel alloys. These coatings predominantly fail by adhesion, plastic deformation and brittle fracture. A microscopic model for fracture of brittle materials, under both static and dynamic conditions for abrasive and adhesive wear correlates very well with the behaviour of these coatings. Analytical interpretation of adhesive wear was made by separately calculating the coefficient of wear "K" of the counterbodies. This information enables an improved understanding of the wear test itself to be added to the model of the wear mechanisms involved.

This diploma thesis is focused to nickel coatings on magnesium alloys. At the introduction of this work is briefly commented phase composition of AZ91 alloy, which is followed by detailed description of five very different theories of Ni-P coatings formation. Theoretical part is ended by review aimed to current states of development in areas of chemical nickel coating, influence of AZ91 alloy microstructure to current less deposition and possibility of surfactants influence to decrease of surface roughness. In experimental part of this thesis was the morphology and composition of Ni-P coatings including interlayers dependence on chemical composition of nickel-plating bath and magnesium alloy surface pre-treatment investigated using scanning electron microscopy and inverted optical microscopy. Average phosphorus content was obtained using energy dispersive analysis. Closing part of experimental part was dedicated for mechanical properties of coatings by micro-indentation analysis.

The microelectronics industry requires continuous advances due to ever-evolving technology and the corresponding need for higher density substrates with smaller features. Specifically, new dielectric materials with enhanced electrical properties are needed. At the same time, adhesion must be maintained in order to preserve package reliability and mechanical performance. As a result, this research investigates the use of thin glass sheets as an alternative substrate material as it offers a number of advantages including coefficient of thermal expansion similar to silicon, good dielectric properties and optical transparency to assist in the alignment of buried features. As part of this project it was necessary to deposit metallic coatings onto the glass sheets to create electrical tracks, pads and microvias. In order to meet these requirements, the metallisation of both smooth as received glass surfaces and surfaces roughened by laser machining using electroless copper and nickel deposition were investigated. This study resulted in a number of important conclusions about the roles of chemical bonding and mechanical anchoring in both the adhesion and catalyst adsorption, that are key factors in the electroless metallisation process.....

Prof. Dr. Renato Altobelli Antunes / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Nanociências e Materiais Avançados, 2016. / Corrosão e desgaste são processos destrutivos que causam enormes prejuízos, comprometendo a segurança de pessoas e das instalações industriais, residenciais e comerciais. Para aumentar a vida útil de elementos de máquinas, por exemplo, revestimentos de níquel obtidos por deposição química são largamente utilizados por sua excelente resistência à corrosão e ao desgaste, boa soldabilidade e brasagem. Por meio do processo de deposição química, a obtenção de ligas e compósitos diversos é possível, visando reforçar e/ou alterar propriedades magnéticas, elétricas, óticas e mecânicas, como dureza, lubricidade, ductilidade, coeficiente de fricção entre outras. A adição de compostos contendo tungstênio nos banhos de deposição química leva à obtenção de revestimentos ternários Ni-W-P, o que afeta o comportamento de corrosão e as características tribológicas dos revestimentos de Ni-P. Neste trabalho realizou-se a incorporação de tungstênio a revestimentos de Ni-P por meio de deposição química, variando-se a concentração de tungstênio por meio da adição de diferentes teores de tungstato de sódio aos banhos. O objetivo foi desenvolver revestimentos ternários de Ni-W-P e investigar o efeito da adição de tungstênio sobre a estrutura, morfologia, resistência à corrosão e propriedades de atrito das camadas. Os revestimentos foram submetidos a um tratamento térmico por uma hora em diferentes temperaturas a fim de promover a formação de fase de fosfeto de níquel (Ni3P), aumentando sua dureza e resistência ao desgaste. Os resultados indicaram que houve a formação de Ni3P com o tratamento térmico realizado. A incorporação de tungstênio levou à formação de uma camada mais compacta e densa, com teor reduzido de fósforo e maior capacidade de proteção contra a corrosão. Além disso, houve um aumento de dureza dos revestimentos, que foi dependente da temperatura na qual ocorreu o tratamento térmico. O coeficiente de atrito apresentou uma variação complexa, a qual não pode ser associada ao teor de tungstênio nos revestimentos. / Corrosion and wear are destructive processes that cause damage and losses affecting the safety of persons, buildings, bridges and facilities for industrial, commercial or residential use. In order to increase the life of machine elements, for example, the use of nickel coatings obtained by chemical reduction is widely used. Electroless nickel coatings are used for functional or decorative purposes or to restore functional properties. In addition to the excellent corrosion and wear resistance, the coating withstands soldering, welding and brazing. The codeposition of one or more elements to binary nickel alloys aims to enhance and/or change the resistance to corrosion, wear, abrasion, magnetic, electrical, optical, or friction properties. By adding tungsten-containing compounds to the electroless deposition bath ternary Ni-W-P are obtained, thus affecting the corrosion behavior and tribological properties of the Ni-P film. In this work, the incorporation of tungsten to Ni-P coatings was carried out using electroless depositon, varying the content of sodium tungstate in the bath. The aim was to develop ternary Ni-W-P coatings and to investigate the effect of tungsten incorporation on the structure, morphology, corrosion behavior and friction properties of the deposited layers. The coatings were annealed for one hour at different temperatures so as to promote the formation of nickel phosphide phases, increasing its hardness and wear resistance. The results showed that Ni3P was formed upon annealing. Tungsten incorporation allowed the formation of a more compact and dense film with reduced phosphorus content and improved corrosion protective ability. Moreover, hardness was increased, but this effect was dependent on the annealing temperature. The coefficient of friction showed a complex variation which does not allow to identify a clear relationship with the tungsten content in the film.

The aim of this diploma thesis was summary of all steps and knowledge necessary to deposition of quality Ni-P coatings deposited on wrought magnesium alloys AZ31 and AZ61. There is the treatise about wrought magnesium alloys AZ31 and AZ61. Thesis includes its phase composition in the theoretical part. There are given its possible processing methods too. Next, there is desribed the mechanism of deposition of Ni-P coatings, components required to electroless deposition and factors affecting the quality and properties of these coatings. The theoretical part is ended by serie of reviews. Authors of these reviews deal with pretreatment of substrates, preparation, characterization and measuring of mechanical, structure and corrosion properties of deposited coatings. The optimalization of pretreatment, parametres and composition of nickel bath suitable for magnesium alloys is described in experimental part. The microstructure, present interlayer between substrate and Ni-P coating and chemical composition of deposited coatings was observed and measured by optical and electron microscopy. The mechanical characterization of Ni-P coatings was performed by microhardness tester.