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Effect of surface treatments on interfacial strength and durability of metal-polymer composite bondSumaiya, Syeda Noor E 14 September 2016 (has links)
Effect of surface treatments on Strength and durability of aluminum 6061-Henkel Hysol EA 9891RP (room temperature curing epoxy) bond was studied using single lap shear, flatwise tensile and wedge crack test. The interfacial strength (IFSS) and % cohesive fracture varied with composite adhesive thickness and 0.03-0.04 mm that maximized the interfacial fracture was chosen to compare surface treatments. The effect of treatments on IFSS and tensile strength increased in the following order: PAA+BR127 (RT) < UT+BR127 (120oC) < Alodine < Alodine+EC3901(RT) < Alodine+BR127 (RT) < PAA < UT < UT+BR127 (RT) < Alodine+EC3901 (90oC) < PAA+EC3901(RT) < PAA+EC3901(90oC) < PAA+BR127 (120oC) < UT+EC3901(90oC) < UT+EC3901(RT) < Alodine+BR127 (120oC). The environmental durability decreased in the following order Alodine+EC3901 (90oC) < Alodine+BR127 (120oC) < PAA+BR127 (120oC) < PAA+EC3901 (90oC) < UT < UT+EC3901 (90oC) < UT+EC3901 (RT) < PAA+EC3901 (RT). PAA and Alodine, combined with BR127 (120 oC) and EC3901 (90oC) are the optimal surface treatments / October 2016
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Pretreatments for metal-to-metal bondingCritchlow, Gary W. January 1997 (has links)
No description available.
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Advanced materials for block copolymer lithographyBates, Christopher Martin 11 July 2014 (has links)
The multi-billion dollar per year lithography industry relies on the fusion of chemistry, materials science, and engineering to produce technological innovations that enable continual improvements in the speed and storage density of microelectronic devices. A critical prerequisite to improving the computers of today relies on the ability to economically and controllably form thin film structures with dimensions on the order of tens of nanometers. One class of materials that potentially meets these requirements is block copolymers since they can self-assemble into structures with characteristic dimensions circa three to hundreds of nanometers. The different aspects of the block copolymer lithographic process are the subject of this dissertation. A variety of interrelated material requirements virtually necessitate the synthesis of block copolymers specifically designed for lithographic applications. Key properties for the ideal block copolymer include etch resistance to facilitate thin film processing, a large interaction parameter to enable the formation of high resolution structures, and thin film orientation control. The unifying theme for the materials synthesized herein is the presence of silicon in one block, which imparts oxygen etch resistance to just that domain. A collection of silicon-containing block copolymers was synthesized and characterized, many of which readily form features on approximately the length scale required for next-generation microelectronic devices. The most important thin film processing step biases the orientation of block copolymer domains perpendicular to the substrate by control of interfacial interactions. Both solvent and thermal annealing techniques were extensively studied to achieve orientation control. Ultimately, a dual top and bottom surface functionalization strategy was developed that utilizes a new class of "top coats" and cross-linkable substrate surface treatments. Perpendicular block copolymer features can now be produced quickly with a process amenable to existing manufacturing technology, which was previously impossible. The development of etching recipes and pattern transfer processes confirmed the through-film nature of the features and the efficacy of both the block copolymer design and the top coat process. / text
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Comparação das propriedades das superfícies da poliamida 6.6. tratada por plasma e por radiação ionizante / Comparison of the properties polyamide 6.6 surfaces treated by plasma and by ionizing radiationIRINEU, ROSA M. da S. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:33:18Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:16Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Comparação das propriedades das superfícies da poliamida 6.6. tratada por plasma e por radiação ionizante / Comparison of the properties polyamide 6.6 surfaces treated by plasma and by ionizing radiationIRINEU, ROSA M. da S. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:33:18Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:16Z (GMT). No. of bitstreams: 0 / Este trabalho tem por objetivo a comparação das propriedades da superfície da poliamida 6.6 tratada por plasma e por radiação ionizante, assim como determinar qual a melhor técnica e condição para ativação da superfície, visando a adesão da mesma e borracha poliacrílica utilizada na fabricação de retentores automotivos. O tratamento da poliamida 6.6 por plasma foi realizado utilizando um equipamento Electronic DIENER Plasma Surface- Technology LFG40, com gás nitrogênio à pressão de 1,40 kg/cm2. As amostras de poliamida 6.6 também foram tratadas por radiação ionizante, à pressão atmosférica e em vácuo, utilizando um acelerador industrial de elétrons, Dynamitron JOB 188, com dose de radiação de 5, 10, 20, 40, 50, 100, 200, 300, 400 e 500kGy com taxa de dose de 11,22 kGy/s para todas as doses e taxa de 11,22 kGy/s e 22,38 kGy/s para a dose de 20kGy. Após os processos de modificação da superfície da poliamida 6.6, parte das amostras não tratadas, tratadas por plasma e por radiação ionizante foram incorporadas à borracha poliacrílica, e outra parte foi destinada a caracterização da superfície utilizando as técnicas de MEV/EDS, FT-IR, PIXE/RBS, AFM e ângulo de contato. As amostras não tratadas e as amostras irradiadas não aderiram à borracha poliacrílica. As amostras tratadas por plasma aderiram à borracha poliacrílica com eficiência e apresentaram diferenças de rugosidade, nas análises de MEV e AFM, e aumento no ângulo de contato quando comparado com as amostras não tratadas. As amostras irradiadas não apresentaram diferenças significativas de propriedades nas análises utilizadas neste trabalho, quando comparadas com as amostras não tratadas. A radiação ionizante não foi eficiente na modificação da superfície da poliamida 6.6 para aderência à borracha poliacrílica. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Influence of zinc on surface treatments of aluminium-zinc alloysGentile, Marialuisa January 2010 (has links)
This research work studies the influence of zinc on surface treatments such as mechanical polishing, anodic alkaline etching, alkaline etching and electropolishing. Solid-solution binary alloys containing 0.6, 1.0 and 1.9at.%Zn were investigated using scanning and transmission electron microscopies and ion beam analysis. Initially, the near-surface composition of the surface pretreated aluminium alloys were determined using Rutherford backscattering spectroscopy (RBS), medium energy ion scattering (MEIS) and glow discharge optical spectroscopy (GDOES). Subsequently, the surface morphologies of the pretreated specimens were characterized by secondary electron microscopy (SEM) and atomic force microscopy (AFM). Further related work was undertaken on the effect of the employed surface treatments on the anodic behaviour of aluminium-zinc alloys. A final analysis was carried out on the influence of grain orientation on zinc enrichment and surface morphologies of aluminium-zinc alloys developed during alkaline etching.The results reveal that surface pretreatments of aluminium-zinc alloys lead to zinc enrichment at the alloy/film interface. The number of zinc atoms contained in the enriched layer depends upon the employed surface pretreatment and the alloy composition. Surface pretreatments influence the topography of Al-Zn alloys. In particular, for electropolishing, alkaline etching and anodic alkaline etching, the resultant surface morphologies were associated with the oxidation-dissolution-precipitation mechanisms occurring at the alloy/film interface and at the film/solution interface. Anodizing of Al-Zn alloys shows that the anodic films growth on Al-Zn alloys in rolled condition and after surface treatment becomes detached from the substrate independently of the surface treatment employed, although detachment of the anodic film occur earlier on surface pre-treated Al-Zn alloys that developed zinc enrichment. The final studies correlated the mechanisms of oxidation and dissolution with the grain orientation. The result revealed that the (111) grain dissolves faster than other grains, while the higher number of zinc enriched atoms were measured on the (001) grain.
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Laboratory evaluation of surface treatments to asphaltic pavements in MississippiJordan, Walter Stephens 01 May 2010 (has links)
Chip and scrub seal treatments are one of the most common pavement preservation practices, however, no performance specifications exist in Mississippi. Review of literature has shown the treatment of cores being successful in reducing the viscosity of aged asphalt pavements. The purpose of this thesis is to provide a basis for performance based specifications for surface treatments in Mississippi. This thesis provides information pertaining to viscosity, moisture loss, and frosted marble analysis of emulsions and the effects of rejuvenation after application of emulsions to aged asphalt pavements which are vital to the performance of the surface treatment. The objectives to this thesis are to determine and evaluate the effects of rejuvenation, frosted marble test, and moisture loss of emulsion applied to aged asphalt pavements. Results from these analysis’ are favorable for developing or providing a basis for performance based specifications for surface treatments applied in Mississippi.
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Análise histomorfométrica de implantes hidrofóbicos e hidrofílicos: estudo experimental em coelhos / Comparative histomorphometric analysis of hydrophobic and hydrophilic implants: an experimental study in rabbitsCunha, Verena Souza da 03 June 2015 (has links)
O íntimo contato entre osso e implante é considerado um pré-requisito fundamental para o sucesso dos implantes dentários, condição esta conhecida como osseointegração. Devido a isto, um grande número de pesquisas com tratamentos de superfícies de implantes vem sendo desenvolvido por várias empresas nos últimos anos, visando acelerar esse fenômeno. O objetivo deste trabalho é avaliar histomorfometricamente o percentual de contato osso-implante (BIC) e área de osso novo (BA) entre implantes de tratamento de superfície Neoporos (GC - hidrofóbico) e implantes com energia de superfície molhada Acqua (GE - hidrofílicos). Foram utilizados 15 coelhos da raça new zealand, que receberam 30 implantes divididos em cada lado de suas tíbias direita e esquerda, ambos de titânio comercialmente puro grau IV com 3.5x8mm de dimensão, sendo ao final de 15 dias, a região dos implantes coletada e processada histologicamente para obtenção de cortes teciduais não desmineralizados, embora dois implantes do grupo Esm tenham sido excluídos da pesquisa devido à instalação ter ocorrido dentro do canal medular e terem obtido tecido necrosado, não cumprindo as características de osseointegração. Para análise dos dados estatísticos, utilizou-se o teste t de Students para amostras independents e teste Mann-Whitney Rank Sum com nível de significância de p<0.05. Os resultados mostraram que não houve diferença estatisticamente significante entre os grupos para a análise de BIC. O grupo GC apresentou a média de 42.9% de BIC, ligeiramente menor que o grupo GE, que apresentou 49.3% de média. Já para o teste BA houve diferenças de 15%, em que o grupo GC apresentou 58.6% e o grupo GE, 74.4%. A conclusão é que há, ainda, necessidade de maiores estudos a cerca do referido tema. / The near contact between bone and implant is considered an essential pre-requisite for the success of dental implants, a condition known as osseointegration. Due to it, a great amount of researches on implants surface treatments has been developed by several companies in recent years to accelerate the phenomenon of osseointegration. The aim of the present study is to evaluate histomorphometrically the percentage of bone-implants contact (BIC) and the area of new bone (BA) between implants with surfaces treatment Neoporos (GC - hydrophobic) and implants with wets surface energy Acqua (GE - hydrophilic). It was used fifteen (n=15) New Zealand rabbits, which received thirty implants installed dividing them between its right and left tibias. Implants were commercially pure titanium grade IV with 3.5x8mm dimension. After fifteen days, the implants area were collected and processed histologically in order to obtain not demineralized tissue sections. For statistical data analysis, it was used the t test for independents samples and Mann-Whitney Rank Sum test. The significance level was p<0.05. Results showed no statistical significant difference between groups for BIC analysis. The control group showed a mean of 42.9% of BIC, slightly lower than the GE group, which showed a mean of 49.3%. For BA test, there was a significant difference of more than 15% in the control group (58.6% for the GC group and 74.4% for GE group). It was concluded that futher studies is needed on this topic of osseointegration and hydrophobic /hydrophilic implants.
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Estudo da corrosão nas ligas de alumínio 3105 e 5052Scarabotto, Mônica January 2018 (has links)
A resistência à corrosão das ligas de alumínio está relacionada ao meio de exposição, composição química, presença de intermetálicos e microestrutura do metal, entre outras. Neste trabalho investigou-se a corrosão nas ligas de alumínio 3105 H16 e 5052 H34, comumente utilizadas na indústria de carrocerias de ônibus, em meio aquoso continham íons agressivos, tais como cloretos, sulfatos e hidroxilas. Avaliou-se comparativamente o comportamento destas ligas com os revestimentos de proteção de Nanocerâmico, Cromo VI, Cromo III e Sistema de Pintura em exposição atmosférica acelerada e imersão em diferentes meios agressivos. Estudos mais aprofundados restringiram-se às ligas sem tratamento, para as quais foram realizados ensaios de exposição acelerada em névoa salina neutra, névoa salina acética, câmara de umidade e exposição atmosférica natural. Microscopia eletrônica de varredura por emissão de campo foi empregada para caracterizar a superfície das ligas antes e após os ensaios de névoa salina neutra e acética. O comportamento eletroquímico das ligas sem tratamento foi determinado através do monitoramento do potencial de circuito aberto, curvas de polarização potenciodinâmica anódicas e espectroscopia de impedância eletroquímica. Os resultados mostraram que o tratamento de Cromo VI foi o que obteve melhor desempenho na proteção de ligas de alumínio, particularmente para a liga 5052. De um modo geral, a liga 5052 apresentou maior resistência à corrosão nos meios testados em presença ou não de tratamentos superficiais. Na exposição à névoa salina, a corrosão manifestou-se principalmente na forma de pites. Ficou comprovado que o efeito do íon Cl- é importante, porém o fator preponderante do comportamento à corrosão das ligas de alumínio está relacionado ao pH do meio de exposição, sendo este recomendado para avaliar revestimentos protetores. Além das condições do meio ao qual o metal será exposto, na seleção de tratamentos anticorrosivos é importante considerar as particularidades de cada liga, uma vez que suas características composicionais e microestruturais exercem relevante influência no desempenho à corrosão. / The corrosion resistance of aluminum alloys is related to the exposure medium, chemical composition, presence of intermetallic particles and metallic microstructure, among others. This work investigated corrosion of 3105 H16 and 5052 H34 aluminum alloys commonly used in the bus body industry in aqueous media containing aggressive ions, such as chlorides, sulfates and hydroxyls. The behavior of these alloys with the protective coatings of Nanoceramic, Chromium VI, Chromium III and Paint System in accelerated atmospheric exposure and immersion in different aggressive media was evaluated comparatively. Further studies were restricted to untreated alloys for which accelerated exposure tests were performed on neutral salt spray, acetic salt spray, moisture chamber and natural atmospheric exposure. Field scanning electron microscopy was used to characterize the alloys surface before and after neutral and acetic salt spray tests. The electrochemical statement of the untreated alloys was determined by monitoring the open circuit potential, anodic potentiodynamic polarization curves and electrochemical impedance spectroscopy. Results have shown that the treatment with Chromium VI was the one that obtained better performance in the protection of the aluminum alloys, particularly for 5052 alloy. In general, 5052 aluminum alloy presented greater resistance to corrosion in all tested media, with or without surface treatments. Under salt spray exposure, the corrosion attack appeared mainly in the form of pitting. It has been proven that the effect of Cl- ion is important, but the predominant factor on the corrosion behavior of aluminum alloys is related to the pH of the exposure medium, which is recommended to evaluate protective coatings. Besides the conditions of the medium to which the metal will be exposed, in the selection of anticorrosive treatments it is important to consider the particularities of each alloy, since its compositional and microstructural characteristics exert a relevant influence on the corrosion performance.
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Efeitos do intemperismo em argamassas de rejuntamentoLopes, Camila Viviane January 2015 (has links)
Com a publicação e vigência da norma brasileira de desempenho NBR 15575:2013 amplia-se a necessidade de pesquisas que avaliem os fatores influentes sobre o desempenho dos materiais em função do local em que são empregados, principalmente no caso de materiais cimentícios, uma vez que, além de serem altamente utilizados no país, são severamente danificados por condições de umidade, radiações solares e variações de temperatura. Sendo assim, frente à exposição e função da argamassa de rejuntamento em sistemas de revestimento aderido, o material de preenchimento requer maior atenção principalmente porque o seu desempenho de forma isolada afeta no desempenho do sistema como um todo, seja do ponto de vista estético, de estanqueidade à água ou de segurança ao uso. Dessa forma, objetivando avaliar a influência do intemperismo sobre o desempenho de argamassas de rejuntamento à base de cimento Portland, essa pesquisa desenvolveu um plano experimental com 4 variáveis de influência, quais sejam: fabricante da argamassa (três níveis), cor da argamassa (branco, cinza e preto), tratamento superficial (sem tratamento, dois produtos hidrofugantes de bases diferentes) e tipo de exposição (referência, natural e artificial). A exposição ao intemperismo natural ocorreu na cidade de Porto Alegre durante 252 dias e a exposição artificial foi realizada em simulador ambiental do tipo radiação UVA e umidade por condensação durante 140 dias. Os resultados apontam para degradação física das argamassas do ponto de vista de alteração de cor e aumento da absorção de água das argamassas após intemperismo. A aplicação de produtos de proteção altera a cor das argamassas, sendo que o tratamento à base de metil siliconato de potássio causa manchas desuniformes em argamassas escuras e não apresentou melhorias quanto à absorção de água das argamassas de rejuntamento. O ensaio em câmara de intemperismo não foi capaz de reproduzir as degradações alcançadas no ambiente de Porto Alegre para as argamassas pretas. Por fim, todos fatores controláveis de forma isolada têm efeito significativo sobre as características cor, absorção de água e abrasão. Dessa forma, não é possível eleger uma argamassa que atenda de forma satisfatória a todas as propriedades avaliadas, demonstrando a ausência de requisitos em norma. / Since the Brazilian performance standard NBR 15575:2013 was published and entered into effect, the need for research that assesses the factors that influence the performance of materials as a function of the location where they are employed, has grown, especially in the case of cimenticious materials, given that these are not only frequently employed in the country, but also severely damaged by moisture, solar radiation and temperature variations. Because of the exposure and function of tile grout in coating systems, the filling material requires greater attention, mainly because its isolated performance affects the performance of the system as a whole from an aesthetic, water proofing or safety perspective. This research was therefore developed to evaluate the influence of weathering on the performance of grouts based on Portland cement using an experimental plan with 4 variables of influence, namely: the manufacturer of the grout (three levels), the color of the grout (white, gray and black), the surface treatment (without treatment, two water-repellent products with different bases) and type of exposure (reference, artificial and natural). The natural exposure to weather occurred in the city of Porto Alegre for 252 days and the artificial exposure was performed in an UVA radiation and moisture condensation environmental simulator for 140 days. The results point to the physical degradation of the grout regarding the change of color and an increase in water absorption of the grout after weathering. The application of protection products changes the color of the grouts, with the treatment based on Potassium Methyl Siliconate causing uneven staining in dark grouts without presenting improvements regarding the water absorption of the tile grout. The test in the weathering chamber wasn't able to reproduce the degradation reached in the environment of Porto Alegre for the black grouts. Finally, all controllable factors in isolation had a significant effect on the Color, Water Absorption and Abrasion characteristics. It's therefore not possible to point to a mortar that meets all assessed properties in a satisfactory manner, demonstrating the non-compliance with the requirements in the standard.
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