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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

Thesis (M.S.) -- Worcester Polytechnic Institute. / Keywords: palladium composite membrane; leak formation. Includes bibliographical references (leaves 107-112).

Magister Philosophiae - MPhil / Pd based membranes are known for their incredible selectivity towards H2. In order for Pd membranes to display high H2 selectivity, a defect free layer of Pd needs to be deposited onto a support. Although various fabrication techniques do exist, many researchers have attempted to produce defect free Pd-based films, using electroless plating. The first step in the preparation technique involves “seeding” of the support structure. Even though these seeds, if well distributed and anchored to the support, are crucial in order to obtain the defect free Pd layer, they hardly ever received attention from the science community. This thesis reports findings on various seeding methods as well as the resulting microstructures of the Pd films formed as a result of the type of seeding method employed. Finally the quality of the membranes using the most promising seeding technique was determined by subjecting the membranes to permeance tests with N2 at both high and low temperatures as well as with H2 at high temperatures.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements of the degree of Master of Science. November 1995. / The preparation of supported cobalt and gold catalysts by the technique of electroless plating, and the establishment of the influence of synthesis variables on the physical properties of the supported catalyst, forms the basis of this dissertation. In both the cases of cobalt and gold supported on extruded cylindrical alumina pellets, the penetration profile of the metal into the support showed dependence on the pH of the activation solution, while the metal loading onto the same support showed no dependence on pH of the activation solution at all. The variables involved in the plating process of the activated pellets, namely: i) the concentration of the activation solution, ii) pH and temperature of the plating bath, iii) plating time, and Iv) variation of the concentrations of components of the plating bath all influenced the mass of metal loaded onto the support, but not the penetration characteristics. It is therefore possible to prepare a supported catalyst with very specific , properties using the above information. Under similar conditions, with extruded alumina pellets as support and with the specific plating formulations used, gold showed higher metal loadings at lower gold concentrations than cobalt.

This study focused on improvement of electroless plating methods by use of particular bath additives. The techniques developed here can enable us to plate very thin layers selectively on a nonconductive substrate and thus create metallized features on a nanoscale. Through the development of such bottom-up techniques this work contributes a key technology to achieving self-assembled nanocircuits. The use of additives in an electroless plating environment can modify the barriers to nucleation (or seeding) and growth. Two additives, namely 3-mercapto-1-propanesulfonic Acid (MPS) and 1,3-propanedisulfonic acid (PDS), notably increased the selectivity of electroless metallization on chemically modified surfaces, which can be used to create patterned structures. More specifically, the additives increased the growth rate of metal on an aminosilane-coated surface relative to an uncoated surface. This work includes an examination of metal layer thickness and conductivity in addition to selectivity. The layer thickness was determined through the use of atomic force microscopy on surfaces that exhibited conductivity. The conductivity of the surface metal was determined through a measurement on a four-point probe measurement. In this series of experiments, the disulfonate-containing additive PDS provided the highest nucleation density, highest conductivity and the best selectivity ratio. The palladium metal deposit on the PDS-treated surface was nearly uniform in height and its conductivity approached the bulk conductivity of palladium with a metal height of less than 30 nm. MPS-treated surfaces also provided increased nucleation density when used during the seeding step, but the resulting conductivity was less than that of the PDS treated samples. We recommend the use of PDS as an effective electroless plating additive for use in palladium electroless plating processes.

Esta Tese descreve a preparação de novos eletrodos modificados (EMs) fazendo uso de um método novo, a deposição de partículas de metais nobres, como níquel, paládio e platina sobre partículas de metais comuns, como cobre e ferro. Este método leva aos denominados EMs mistos, que podem apresentar características diferentes e mais eficientes que os EMs Ni, Pd e Pt já estudados, sendo a principal aplicação nas reações de hidrogenação eletrocatalítica (HEC) de substratos orgânicos insaturados. A preparação dos EMs mistos se inicia pelo recobrimento da superfície do eletrodo de trabalho com um filme polimérico. O polímero usado foi o poli-(éter alílico do ácido p-benzenossulfônico), um filme aniônico com boa estabilidade química e mecânica, que pode fazer troca iônica de seus íons H+ por cátions metálicos. Este filme é preparado por varreduras de voltametria cíclica de uma solução do respectivo monômero, que se oxida eletroquimicamente iniciando a reação química de polimerização. Os metais cobre e ferro são introduzidos ao polímero pelo método de troca iônica/redução eletroquímica, onde o EM é mergulhado em uma solução saturada de um sal de cobre ou de ferro para ocorrer a troca iônica. Em seguida, estes íons são reduzidos eletroquimicamente por varreduras de voltametria cíclica, usando uma faixa de potencial adequada. Para se preparar os EMs mistos, mergulhou-se estes EMs (Cu ou Fe) na solução do banho electroless de níquel, paládio e platina. Por esta metodologia partículas destes metais nobres são depositadas pelo processo de deposição metálica electroless (DME), que faz uso de um agente redutor, hipofosfito de sódio, para reduzir os íons destes metais de forma adequada nos EMs Cu ou Fe e onde se espera obter grande área superficial. Os EMs mistos preparados foram: Cu/Ni, Cu/Pd, Cu/Pt, Fe/Ni, Fe/Pd e Fe/Pt. A caracterização dos metais dos EMs mistos foi feita indiretamente por geração eletroquímica de hidrogênio (GH) de uma solução ácida e diretamente pelas técnicas de Difração de Raios X e Microscopia de Varredura Eletrônica (MEV). O processo de deposição metálica foi investigado por medidas de potencial de circuito aberto, realizadas durante a deposição dos metais nobres que indicou a ocorrência do processo de DME em alguns casos e DG (deposição galvânica) em outros. Devido a alguns resultados do processo de deposição metálica, foi estudado o mecanismo de catalise na deposição direta das partículas de níquel, paládio e platina pela redução química por hipofosfito dos íons correspondentes. Preparou-se EMs Ni, Pd e Pt por dois métodos: troca iônica/redução eletroquímica e troca iônica/redução química catalisada pelo filme. Estes foram caracterizados por GH e utilizando o ácido p-toluenossulfônico como modelo, estudos de espectroscopia na região UV/Vis. foram realizados. Estas medidas comprovaram a catálise, pois os EMs preparados por redução química apresentaram melhores resultados para a GH e as análises de UV/Vis. mostraram a forte ligação existente entre os grupos sulfonatos do polímero e os íons metálicos bivalentes, ligação essencial para ocorrer a catálise do filme. Verificou-se que as partículas dos metais nobres podiam estar sendo depositadas por DME ou por DG seguido de DME, mas que em todos os casos ocorria a deposição causada pela catálise do filme. A reatividade dos EMs mistos foi avaliada por um estudo cinético, onde HECs de alguns substratos orgânicos foram realizadas e acompanhadas por medidas de UV/Vis. durante as reações. Obteve-se a constante de velocidade (k) destas reações, as quais foram comparadas entre si e encontrou-se como o EM misto mais eficiente o Cu/Pt. As ks das reações deste EM foram comparadas com ks de outros EMs de Pt, já estudados em nossos laboratórios. / This thesis describes the preparation of new modified electrodes (MEs) using the method of noble metal particles deposition like nickel, palladium and platinum in the surface of commum metals particles as cooper and iron. This new electrodes were denominated mixed MEs, and can show different caractheristics and present higher efficiency than others already studied, being their principal application in electrocatalytic hydrogenation (ECH) of unsaturated organic substrates. The surface electrode were coated with the polymer poly-(ether allyl p-benzenesulfonic), an anionic film with good chemical and mechanic stability that can undergoes ion exchange of ions H+ by metallic cations. This film is prepared by anodic oxidation of the monomer using voltammetric cycles, producing a cation radical initiador of a chain reaction polymerization. Cooper and iron metals are incorporated in the polymer by ion exchange/ electrochemical reduction; the ME were dipped in saturated solution of cooper or iron salt to produce the ion exchange. The ions are then electrochemically reduced. The preparation of mixed MEs is carried out by electrolessly deposidated Ni, Pd or Pt. This methodology use NaH2PO2, to reduce the metal ions. This procedure deposits Ni, Pd and Pt in the surface of Cu or Fe MEs with an expected higher superficial area. The mixed Cu/Ni, Cu/Pd, Cu/Pt, Fe/Ni, Fe/Pd e Fe/Pt MEs were prepared. The characterization of the MEs metals was made indirectly by electrochemically hydrogen generation from an acid solution (HG) and directly by SEM-EDX and Ray X Diffraction analysis. The metallic deposition process was investigated by open circuit during the deposition of nobles metals that indicate the occurrence of electroless deposition (EMD) process in some cases or spontaneous displacement reaction (galvanic deposition - GD) in others. Despite the two mechanisms related above, a catalytic process would occur. To rut in evidence this third process Ni, Pd and Pt MEs were prepared by two methods: ion exchange/electrochemical reduction and ion exchange/chemical reduction catalyzed by the film. The resulting MEs were characterized by HG and spectroscopy in the UV/Vis. For this last analysis, p-toluenossulfonic acid was used as model and the results proved the catalytic mechanism. UV spectroscopy analysis showed strong bonds between the p-toluenossulfonic and the noble metal salts. So particles of noble metals can be deposited not only by EMD or GD but in all cases occur the deposition by film catalysis too. The reactivity of mixed MEs was done by kinetic study, where ECH of some organic substrates were carried out and monitored by UV/Vis spectroscopy. The constant rate (k) of the reactions was calculated and compared with the others mixed MEs. The ks of this ME were compared with the ks of other Pt MEs, already studied. The more reactive of them was the Cu/Pt ME.

Avatrel 8000P's excellent photo-definition properties and mechanical strength make it an ideal polymer collar material. Avatrel 8000P is a high contrast, I-line sensitive mixture that can be developed in traditional aqueous-base developers. The great photolithographical performance of this photopolymer can be partly contributed to the minimal amount of light absorbed by the base norbornene polymer. The processing conditions noted in this work are an optimized version, which have been shown to give superior photolithographical performance. The simple baking procedures make Avatrel 8000P easier to process than SU-8. The ability to develop Avatrel 8000P in aqueous base can reduce chemical waste. As shown by SEM images, high fidelity structures with aspect ratios of 7:1 can be fabricated in thick films with vertical sidewalls. Bonding between two copper surfaces over various gap sizes was achieved by electroless deposition without the addition of surfactants or inhibitors in the bath. The effect of anneal temperature on the electroless bond formed was analyzed. The electroless bond strength increased with anneal temperature. However, the bond strength estimation for samples annealed at 80°C to 120°C is a minimum value due to the failure location of most of the pillars and the resulting area used in the calculation of bond strength. Grain growth from copper recrystallization and removal of small defects improve the bond strength. Large voids at the interface of the two pillars were related to rough starting surfaces for the electroplated pillars.

In this work, adhesion between electrolessly deposited copper and dielectric materials for use in microelectronic devices is investigated. The microelectronics industry requires continuous advances due to ever-evolving technology and the corresponding need for higher density substrates with smaller features. At the same time, adhesion must be maintained in order to preserve package reliability and mechanical performance. In order to meet these requirements two approaches were taken: smoothing the surface of traditional epoxy dielectric materials while maintaining adhesion, and increasing adhesion on advanced dielectric materials through chemical bonding and mechanical anchoring. It was found that NH3 plasma treatments can be effective for increasing both catalyst adsorption and adhesion across a range of materials. This adhesion is achieved through increased nitrogen content on the polymer surface, specifically N=C. This nitrogen interacts with the palladium catalyst particles to form chemical anchors between the polymer surface and the electroless copper layer without the need for roughness. Chemical bonding alone, however, did not enable sufficient adhesion but needed to be supplemented with mechanical anchoring. Traditional epoxy materials were treated with a swell and etch process to roughen the surface and create mechanical anchoring. This same process was found to be ineffective when used on advanced dielectric materials. In order to create controlled roughness on these surfaces a novel method was developed that utilized blends of traditional epoxy with the advanced materials. Finally, combined treatments of surface roughening followed by plasma treatments were utilized to create optimum interfaces between traditional or advanced dielectric materials and electroless copper. In these systems adhesion was measured over 0.5 N/mm with root-mean-square surface roughness as low as 15 nm. In addition, the individual contributions of chemical bonding and mechanical anchoring were identified. The plasma treatment conditions used in these experiments contributed up to 0.25 N/mm to adhesion through purely chemical bonding with minimal roughness generation. Mechanical anchoring accounted for the remainder of adhesion, 0.2-0.8 N/mm depending on the level of roughness created on the surface. Thus, optimized surfaces with very low surface roughness and adequate adhesion were achieved by sequential combination of roughness formation and chemical modifications.

Esta Tese descreve a preparação de novos eletrodos modificados (EMs) fazendo uso de um método novo, a deposição de partículas de metais nobres, como níquel, paládio e platina sobre partículas de metais comuns, como cobre e ferro. Este método leva aos denominados EMs mistos, que podem apresentar características diferentes e mais eficientes que os EMs Ni, Pd e Pt já estudados, sendo a principal aplicação nas reações de hidrogenação eletrocatalítica (HEC) de substratos orgânicos insaturados. A preparação dos EMs mistos se inicia pelo recobrimento da superfície do eletrodo de trabalho com um filme polimérico. O polímero usado foi o poli-(éter alílico do ácido p-benzenossulfônico), um filme aniônico com boa estabilidade química e mecânica, que pode fazer troca iônica de seus íons H+ por cátions metálicos. Este filme é preparado por varreduras de voltametria cíclica de uma solução do respectivo monômero, que se oxida eletroquimicamente iniciando a reação química de polimerização. Os metais cobre e ferro são introduzidos ao polímero pelo método de troca iônica/redução eletroquímica, onde o EM é mergulhado em uma solução saturada de um sal de cobre ou de ferro para ocorrer a troca iônica. Em seguida, estes íons são reduzidos eletroquimicamente por varreduras de voltametria cíclica, usando uma faixa de potencial adequada. Para se preparar os EMs mistos, mergulhou-se estes EMs (Cu ou Fe) na solução do banho electroless de níquel, paládio e platina. Por esta metodologia partículas destes metais nobres são depositadas pelo processo de deposição metálica electroless (DME), que faz uso de um agente redutor, hipofosfito de sódio, para reduzir os íons destes metais de forma adequada nos EMs Cu ou Fe e onde se espera obter grande área superficial. Os EMs mistos preparados foram: Cu/Ni, Cu/Pd, Cu/Pt, Fe/Ni, Fe/Pd e Fe/Pt. A caracterização dos metais dos EMs mistos foi feita indiretamente por geração eletroquímica de hidrogênio (GH) de uma solução ácida e diretamente pelas técnicas de Difração de Raios X e Microscopia de Varredura Eletrônica (MEV). O processo de deposição metálica foi investigado por medidas de potencial de circuito aberto, realizadas durante a deposição dos metais nobres que indicou a ocorrência do processo de DME em alguns casos e DG (deposição galvânica) em outros. Devido a alguns resultados do processo de deposição metálica, foi estudado o mecanismo de catalise na deposição direta das partículas de níquel, paládio e platina pela redução química por hipofosfito dos íons correspondentes. Preparou-se EMs Ni, Pd e Pt por dois métodos: troca iônica/redução eletroquímica e troca iônica/redução química catalisada pelo filme. Estes foram caracterizados por GH e utilizando o ácido p-toluenossulfônico como modelo, estudos de espectroscopia na região UV/Vis. foram realizados. Estas medidas comprovaram a catálise, pois os EMs preparados por redução química apresentaram melhores resultados para a GH e as análises de UV/Vis. mostraram a forte ligação existente entre os grupos sulfonatos do polímero e os íons metálicos bivalentes, ligação essencial para ocorrer a catálise do filme. Verificou-se que as partículas dos metais nobres podiam estar sendo depositadas por DME ou por DG seguido de DME, mas que em todos os casos ocorria a deposição causada pela catálise do filme. A reatividade dos EMs mistos foi avaliada por um estudo cinético, onde HECs de alguns substratos orgânicos foram realizadas e acompanhadas por medidas de UV/Vis. durante as reações. Obteve-se a constante de velocidade (k) destas reações, as quais foram comparadas entre si e encontrou-se como o EM misto mais eficiente o Cu/Pt. As ks das reações deste EM foram comparadas com ks de outros EMs de Pt, já estudados em nossos laboratórios. / This thesis describes the preparation of new modified electrodes (MEs) using the method of noble metal particles deposition like nickel, palladium and platinum in the surface of commum metals particles as cooper and iron. This new electrodes were denominated mixed MEs, and can show different caractheristics and present higher efficiency than others already studied, being their principal application in electrocatalytic hydrogenation (ECH) of unsaturated organic substrates. The surface electrode were coated with the polymer poly-(ether allyl p-benzenesulfonic), an anionic film with good chemical and mechanic stability that can undergoes ion exchange of ions H+ by metallic cations. This film is prepared by anodic oxidation of the monomer using voltammetric cycles, producing a cation radical initiador of a chain reaction polymerization. Cooper and iron metals are incorporated in the polymer by ion exchange/ electrochemical reduction; the ME were dipped in saturated solution of cooper or iron salt to produce the ion exchange. The ions are then electrochemically reduced. The preparation of mixed MEs is carried out by electrolessly deposidated Ni, Pd or Pt. This methodology use NaH2PO2, to reduce the metal ions. This procedure deposits Ni, Pd and Pt in the surface of Cu or Fe MEs with an expected higher superficial area. The mixed Cu/Ni, Cu/Pd, Cu/Pt, Fe/Ni, Fe/Pd e Fe/Pt MEs were prepared. The characterization of the MEs metals was made indirectly by electrochemically hydrogen generation from an acid solution (HG) and directly by SEM-EDX and Ray X Diffraction analysis. The metallic deposition process was investigated by open circuit during the deposition of nobles metals that indicate the occurrence of electroless deposition (EMD) process in some cases or spontaneous displacement reaction (galvanic deposition - GD) in others. Despite the two mechanisms related above, a catalytic process would occur. To rut in evidence this third process Ni, Pd and Pt MEs were prepared by two methods: ion exchange/electrochemical reduction and ion exchange/chemical reduction catalyzed by the film. The resulting MEs were characterized by HG and spectroscopy in the UV/Vis. For this last analysis, p-toluenossulfonic acid was used as model and the results proved the catalytic mechanism. UV spectroscopy analysis showed strong bonds between the p-toluenossulfonic and the noble metal salts. So particles of noble metals can be deposited not only by EMD or GD but in all cases occur the deposition by film catalysis too. The reactivity of mixed MEs was done by kinetic study, where ECH of some organic substrates were carried out and monitored by UV/Vis spectroscopy. The constant rate (k) of the reactions was calculated and compared with the others mixed MEs. The ks of this ME were compared with the ks of other Pt MEs, already studied. The more reactive of them was the Cu/Pt ME.