Typical surface preparation consists of exposure to cleaning chemical to remove contaminants followed by rinsing with ultra-pure water which is followed by drying. Large quantities of water, various chemicals, and energy are used during rinsing and drying processes. Currently there is no in-situ metrology available to determine the cleanliness of micro- and nano-structures as these processes are taking place. This is a major technology gap and leads to over use of resources and adversely affects the throughput.Surface preparation of patterned wafers by batch processing becomes a major challenge as semiconductor fabrication moves deeper in submicron technology nodes. Many fabs have already employed single wafer tools. The main roadblock for single-wafer tools is their lower throughput. This obstacle is eased by introduction of multi chamber tools. To reduce cycle time and resource utilization during rinse and dry processes without sacrificing surface cleanliness and throughput, in-situ metrology is developed and used to compare typical single wafer spinning tools with immersion tools for rinsing of patterned wafers. This novel metrology technology includes both hardware for an in-situ measurement and software for process data analysis. Successful incorporation of this metrology will eliminate dependency on external analysis techniques such as Inductively Coupled Mass Spectroscopy (ICPMS), Scanning Electron Microscope (SEM), and Tunneling Electron Microscope (TEM), and will lead to fast response time.In this study the electro-chemical residue sensor (ECRS) was incorporated in a lab scale single-wafer spinning and single- wafer immersion tool. The ECRS was used to monitor dynamics of rinsing of various cleans such as ammonium peroxide mixture (APM), hydrochloric peroxide mixture (HPM), and sulfuric peroxide mixture (SPM). It was observed that different cleaning chemicals impact the subsequent rinse not only through adsorption and desorption but also through surface charge. The results are analyzed by using a comprehensive process model which takes into account various transport mechanisms such as adsorption, desorption, diffusion, convection, and surface charge. This novel metrology can be used at very low concentration with very high accuracy. It is used to study the effect of the key process parameters such as flow rate, spin rate, temperature, and chemical concentration.

In sheet metal forming operations the life length of the production equipment islargely dependent on the wear of the tools that are in direct contact with the sheet.One form of adhesive wear where some sheet material gets transferred to the tool, alsoknown as galling, is the most common cause of tool failure. The transferred materialsticks firmly to the tool and will scratch subsequent sheets and increase friction, renderingthem anywhere from aesthetically unsightly to completely ripped apart. Withcareful combination of several parameters the tools production life can be significantlyextended. The surface preparation of the tools has a large influence on the tool life, thesurface has to be smooth and yet not without texture. It was shown in strip reductiontesting that the orientation as well as the depth of the surface texture left by polishinginfluenced the tool life and that a texture perpendicular to the sliding direction was toprefer. The geometry of the forming tool is also a parameter to take into account as itinfluences the tool life not only by changing the contact pressure but also in itself. Ina sliding against flat sheet test rig a lower contact pressure increased the sliding distanceto galling. When two different geometries were compared at the same contactpressure it was found that there was a difference in tool life. As to the tool itself thematerial it’s made of influences the wear rate and tool life. Different tool steels wasinvestigated in sliding wear against metal sheets; Vancron 40 performed better thanVanadis 6 and S290PM performed better than a AISI M2 grade steel.

Surface preparation is the key factor in determining the success of a protective coating system and its ultimate objective is to create proper adhesion of a coating over an underlying substrate. Abrasive blast cleaning involves mechanical cleaning by the continuous impact of abrasive particles at high velocities on to the substrate in a jet stream of compressed air. Industries that use abrasive blasting include the shipbuilding industry, automotive industry, and other industries that involve surface preparation and painting. Materials from different origins can be used as a blasting media including coal slag, smelter slag, mineral abrasives, metallic abrasives, and synthetic abrasives. Purpose of this thesis is to investigate the usability of industrial wastes (coal slag, smelter slags, etc.) of Turkey as abrasives in surface preparation technologies. Four different slag samples of three sources, namely coal furnace slag sample from &Ccedil / ayirhan thermal power plant, ferrochrome slag sample from Eti Krom A.S., granulated blast furnace and converter slag sample from Eregli Iron and Steel Works were studied within the scope of this thesis work. The samples were prepared by crushing and screening. The chemical composition and physical characteristics of the samples were determined. All the samples were tested in industrial scale. Test results showed that the converter slag meet all the specifications for abrasives and it can be used in blast cleaning operations. However, coal furnace slag, granulated blast furnace slag and ferrochrome slag are not suitable to be used as abrasive in surface preparation technologies.

Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Mechanical Engineering, 2009. / Includes bibliographical references.

Title: Photoconductivity, photoluminescence and charge collection in semiinsulating CdTe and CdZnTe Author: Jakub Zázvorka Department: Institute of Physics of Charles University Supervisor of the doctoral thesis: prof. Ing. Jan Franc, DrSc., Institute of Physics of Charles University. Abstract: Cadmium telluride and its compounds with zinc are the material of choice in spectroscopic room temperature high energy radiation detectors. The development of the final device is influenced by many parameters, including material impurities and defects, homogeneity and surface preparation. This thesis offers a comprehensive investigation of the detector fabrication process and of the parameters and physical effects influencing the spectroscopic resolution and performance of the detector. Structure of deep levels is investigated through photoluminescence and correlated with other electro-optical measurements dealing with the impact of structural imperfections of the material and their effect. The influence of resistivity and photoconductivity homogeneity on the detector performance is studied through electrical measurement of the charge carrier transport and charge collection of the sample. Obtained results are explained using the Fermi level shift theory and confronted with a theoretical model and calculations. The...

<p>Most thermal spray coating processes can be divided into three sub-processes; substrate surface preparation, the thermal spray operation and a post-coating surface finishing operation such as honing or grinding. Reliable and robust surface preparation is needed to guarantee maximum coating adhesion to substrates. Traditionally, the grit blasting process is used for surface preparation of materials receiving a thermal spray coating. However, in high volume production, the reproducibility of surface topography decays with time as grit particles are recycled through surface preparation operation. The focus of this project is to enhance the coating's ability to adhere to an aluminum substrate by incorporating high pressure water jet as a surface preparation operation. </p> <p>Water pressure, standoff distance, number of orifices, orifice size and rotation speed are process parameters identified as having an effect on surface roughness and coating adhesion strength. Through classical statistical analysis, main effects as well as 2 and 3 factor interactions are revealed and studied.</p> <p>A direct and significant relationship exists between water pressure, standoff distance and number of orifices. Correlation exists among adhesion strength and surface roughness parameters Ra, Rq and Rtm, respectively. Recommendations are made for further investigation into reducing water pressure and rotation speed requirements while sustaining the same level of surface modification.</p> / Master of Science

Objectives: The purpose of this in-vitro study was to evaluate the effects of three different surface preparation methods on the shear bond strength of orthodontic brackets bonded to zirconia and determine the most appropriate method. Methods: 45 zirconia and 30 leucite-reinforced porcelain mandibular premolar crowns were divided into 5 groups and received the following surface preparations: 37% phosphoric acid and non-hydrolyzed silane, 4% hydrofluoric acid and hydrolyzed silane, microetch with 50μ Al 2 O3 particles. A universal adhesive primer containing MDP was applied and the brackets were bonded with a bis-GMA composite resin. Shear bond strength (SBS) at bond failure and ARI score were recorded. Results: There was a statistically significant difference among the studied groups for the SBS. The highest mean SBS (11.03 MPA) was recorded for the zirconia/microetch group, and the lowest SBS (3.49 MPa) for the zirconia/phosphoric acid group. The leucite-reinforced porcelain/ hydrofluoric acid group had significantly more fractures than any other debond pattern. The zirconia/hydrofluoric acid group was the only one with a SBS (8.08 MPa) that fell within the recommended range of 6-8 MPa. This group also had a favorable debond pattern with most composite remaining on the bracket. Conclusions: Important consideration should be given to the surface preparation of porcelain and zirconia prior to bonding orthodontic attachments. Phosphoric acid etch is not an adequate surface preparation when bonding to zirconia. Hydrofluoric acid is not suitable when bonding to leucite-reinforced porcelain, as it is associated with a higher rate of surface fracture. Microetch with 50μ Al 2 O3 particles in combination with an MDP containing universal adhesive primer provided optimal mean shear bond strength, along with favorable debond patterns when bonding to zirconia. Hydrofluoric acid etch in combination with a silane and a universal primer containing MDP provided acceptable shear bond strength to zirconia. This protocol was not significantly different from zirconia prepared with microetch and either method can be successfully employed.

Silicon-based ceramics and ceramic matrix composites (CMCs), such as silicon carbide (SiC) fiber reinforced SiC, are promising candidates for hot section components in next generation turbine engines. Environmental barrier coatings (EBCs) are essential for implementing these components as they insulate and protect the substrate from reaction with water vapor in the engine environment. EBCs are typically deposited via atmospheric plasma spraying (APS) and preparing the component surfaces through cleaning and roughening prior to coating is a vital step to ensure sufficient coating adhesion. The adhesion of a plasma sprayed coating to the underlying component is one of the most important properties as the component will not be protected if the coating is not well adhered. Surface roughening of metallic components via grit blasting is well documented and understood, but much less is known about preparing ceramic and ceramic composite surfaces for thermal spray coating. Silicon coatings are often used as a bond coating between SiC-based components and EBC top layers, but the adhesion strength of plasma sprayed Si on these substrates, Si splat formation and the factors that affect coating formation and adhesion have not been well studied. The effects of automated grit blasting process parameters on surface roughness and material loss of a reaction bonded SiC (rb SiC) composite were evaluated. Surface roughness before and after grit blasting was evaluated with a confocal laser scanning microscope. The differences and advantages of automated grit blasting compared to manual grit blasting were observed. Most notably was the level of control at high nozzle traverse speeds resulting in reduction of material loss and consistency of roughening. At high nozzle traverse speeds, the amount of material loss decreased greatly with a small effect on induced surface roughness. The degree of grit blasting induced roughness and material loss was found to be largely dependent on the nature of the composite matrix and reinforcement, as well as blast nozzle traverse speed. A statistical model was developed to predict the substrate thickness loss and induced average roughness based on nozzle traverse speed and blast pressure for automated grit blasting. Additionally, laser ablation was used to create controlled, regularly patterned surface texture on rb SiC substrates to further investigate the role of texture parameters in Si coating adhesion. Si was plasma sprayed onto rb SiC substrates to deposit both thick coatings to evaluate adhesion strength and single splats to study splat formation. Surface roughness/texture, substrate preheat temperature and mean Si particle size were varied in plasma spray coating experiments to observe their role in coating adhesion strength. Si adhesion strength was found to be related to all three factors and a statistical model was developed to predict adhesion strength based on them. Substrate preheat temperature had a significant effect on both Si adhesion strength and Si splat formation on rb SiC. Single splat formation during plasma spraying of Si on SiC was simulated with software called SimDrop. Simulations of Si droplet impact, spreading and solidification during plasma spraying on smooth and textured SiC surfaces were used to investigate the effects of relevant process parameters on splat formation. Experimentally observed Si splats on smooth substrates at different temperatures during deposition were matched with simulated splats with the same spraying parameters. A change in thermal contact resistance with changing substrate preheat temperature was confirmed by the simulation results. The role of surface texture parameters for a regularly patterned surface texture in splat formation was demonstrated through simulation. This dissertation investigates methods of roughening and preparing a SiC composite substrate for plasma spray coating, as well as factors which affect the adhesion strength and splat formation of plasma sprayed Si through experiments and simulation. The observations made provide valuable insight for understanding and optimizing the manufacturing processes utilized to deposit strongly adhered coatings onto SiC-based composites. In addition, areas of interest in this field for future study and further investigation are introduced and suggested. / Doctor of Philosophy / Silicon-based ceramics and ceramic matrix composites (CMCs), such as silicon carbide (SiC) fiber reinforced SiC, are promising candidates for hot section components in next generation turbine engines. Environmental barrier coatings (EBCs) are essential for implementing these components as they insulate and protect the substrate from reaction with water vapor in the engine environment. EBCs are typically deposited via atmospheric plasma spraying (APS) and preparing the component surfaces through cleaning and roughening prior to coating is a vital step to ensure sufficient coating adhesion. The adhesion of a plasma sprayed coating to the underlying component is one of the most important properties as the component will not be protected if the coating is not well adhered. Silicon coatings are often used as a bond coating between SiC-based components and EBC top layers, but the adhesion strength of plasma sprayed Si on these substrates, Si splat formation and the factors that affect coating formation and adhesion have not been well studied. This dissertation investigates methods of roughening and preparing a SiC composite substrate for plasma spray coating, as well as factors which affect the adhesion strength and splat formation of plasma sprayed Si through experiments and simulation. The observations made provide valuable insight for understanding and optimizing the manufacturing processes utilized to deposit strongly adhered coatings onto SiC-based composites. In addition, areas of interest in this field for future study and further investigation are introduced and suggested.

Orientador: Edison Bittencourt / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-08T07:44:25Z (GMT). No. of bitstreams: 1 NascimentoNeto_EneasRamos_M.pdf: 883436 bytes, checksum: c17690c5dbef73787fd9632accf5eccc (MD5) Previous issue date: 2006 / Resumo: A crescente preocupação com o desenvolvimento sustentável aliado com uma maior conscientização com relação à preservação do meio ambiente tem impulsionado pesquisas nas mais diversas áreas de tecnologias ambientalmente corretas. Dentro deste contexto a tecnologia de plasma frio representa uma eficiente, ambientalmente correta e econômica alternativa para limpeza da superfície de alumínio. Este trabalho é a primeira etapa do projeto de modificação da superfície de alumínio coordenado pelo professor Edison Bittencourt. O projeto como um todo consiste de três etapas (limpeza, proteção e ativação) e tem a intenção de substituir via plasma o processo químico de limpeza, proteção à corrosão e ativação da superfície. Com relação à segunda etapa já foram realizados, no Instituto de Física pelo físico Carlos Salles Lambert, alguns ensaios de deposição de Hexametildisiloxano que mostraram ser excelentes protetores a corrosão, entretanto, essa segunda etapa não será discutida neste trabalho mas em posteriores teses. Neste trabalho realizou-se a remoção de óleo lubrificante e protetor da superfície de alumínio utilizando os gases oxigênio, hidrogênio, argônio e as misturas: oxigênio e argônio, hidrogênio e argônio. Foi analisada e discutida a influência da potência do gerador, tempo de bombardeamento, tipo de gás e pressão de trabalho sobre o ângulo de contato com água deionizada. A remoção do óleo lubrificante e protetor foi analisada em termos da medida do ângulo de contato de água deionizada e etileno glicol e da análise de XPS. Os experimentos foram realizados segundo técnica de planejamento experimental, em que as análises dos resultados experimentais foram realizadas através da Metodologia da Superfície de Resposta. A análise dos efeitos das variáveis sobre as variáveis de resposta do processo foi utilizada na construção de um modelo empírico, visando, a predição do comportamento do processo. A análise dos modelos obtidos foi realizada através da análise de variância (ANOVA). As variáveis independentes analisadas foram: potência do gerador, tempo de bombardeamento, tipo de gás e pressão de trabalho. Todas as variáveis operacionais foram analisadas em três diferentes níveis. Os resultados obtidos indicam que é possível remover o óleo lubrificante e protetor da superfície de alumínio utilizando o processo de plasma frio / Abstract: The increasing concern with the sustainable development ally with a bigger awareness with regard to the preservation of the environment has stimulated research in the most diverse areas of ambient correct technologies. Inside of this context the cold plasma technology represents an efficient, ambient correct and economic alternative for cleanness of the aluminum surface. It was analyzed and argued the influence of the power of the generator, sputtering time, type of gas and pressure of work on the angle of contact with water. This work is the first stage of the project of modification of the aluminum surface coordinated by professor Edison Bittencourt. The project as a whole consists of three stages (cleaning, protection and activation) and has the intention to substitute the chemical process of cleanness, protection the corrosion and activation of the surface for plasma process. With regard to second stage already they had been carried through, in the Institute of Physics for the physicist Carlos Salles Lambert, some assays of deposition of Hexametildisiloxano had shown to be excellent corrosion protectors, however, this second stage will not be argued in this work but in posterior works. In this work lubricative and protective oil was removed by gases such as oxygen, hydrogen, argon and the mixtures: oxygen and argon, hydrogen and argon. It was analyzed and argued the influence of the power of the generator, time of bombardment, type of gas and pressure of work on the angle of contact with water. The removal of the oil was analyzed in terms of the measure of the angle of contact with water and ethylene glycol and of the analysis of XPS.The experiments were carried out according experimental planning techniques where the obtained experimental results analyses had been carried through the Response Surface Methodology. The analysis of effect of the independent variable on the process answer variables had been used in the construction of an empirical model, aiming to predit the process behavior. The analysis of the obtained models was carried out using the variance analysis (ANOVA). The independent variable used had been: power of the generator, sputtering time, type of gas and pressure of work. The results obtained indicate that it is possible to remove the oil of the aluminum surface using the cold plasma process / Mestrado / Ciencia e Tecnologia de Materiais / Mestre em Engenharia Química

The objective of this study was to increase the bond strength at the surface interface of a thin stainless-steel panel for structural bonding on a helicopter. To achieve this objective, six activation methods for applying the coating to the panel in the surface preparation process are presented and explored. Adhesion and roughness tests were conducted to determine which method consistently initiates the etch and improves the bond at the surface. Based on the test results, three methods proved to be effective in initiating the etch. Of the three effective methods, only one method exhibited significantly improved bond strength at the surface interface as well as consistently initiated the etch in solution. The applicability of this method is discussed, and recommendations are presented for further study.