This diploma thesis is aimed on durability of PVD and CVD coatings for symmetrical face milling. The theoretical part describes the characteristics of cemented carbides, milling technology and the characteristics of the coating methods. The experimental part describes the machine tool, used tools, workpiece material and cutting conditions. The aim of the work was to measure the cutting forces and tool wear during the milling. Based on experiment, it is clear that the PVD coatings with nano-layers achieves to the longer life in comparison with others and generally, that the using of coatings leads to reduction of cutting powers and lifetime was increased.

Over the past decades, cemented paste backfill (CPB) has become a common, environmentally friendly method of managing mine wastes (such as tailings). This technology allows up to 60% of the total amount of tailings to be reused and filled in the mine stopes after converting them into cemented material. Beside reducing the environmental risks associated with the traditional disposal of these materials, turning them into cemented material and placing them in the underground mine stopes can also provide secondary support for these stopes in addition to minimizing the risk of ground subsidence in the mine area. CPB is an engineered mixture of tailings, water, and hydraulic binder (such as cement, blast furnace slag, and fly ash) that is mixed in the paste plant and delivered into the mine stopes through a gravity or pumping based transportation system. During the transportation of CPB through the delivery system pipelines, the flowability of CPB depends on the rheology of the transported CPB, which is affected by different factors, such as the transportation time, temperature variation, binder type, and chemical composition of these mixtures. In addition, the performance of CPB, after placing the CPB mixture into the mine stopes, is mainly dependent on the role of the hydraulic binder, as it increases the mechanical strength of the mixture through the process of cement hydration. The mechanical strength is also influenced by different factors, such as time progress, temperature variation, and presence of chemical additives. It has previously been found that fresh CPB transported and/or placed in the mine stopes can be susceptible to temperature variation of different sources, such as the climatic effects, heat generated from the surrounding rocks, and heat generated during the process of cement hydration. Unsuitable flowability of CPB through the delivery system might lead to significant financial losses due to clogging of pipelines with unexpected hardening of CPB during transportation, which will cause delay in work and possible damages to the pipelines. Also, failure of CPB structure in the mine stopes due to inappropriate mechanical strength may cause casualties to the mine workers as well as significant environmental and economic damages. Many researchers studied the rheological properties and/or strength development of CPB under the individual effect of any of the aforementioned factors. Additionally, many researchers have evaluated the coupled effect of some of these factors on the rheology and mechanical strength of CPB material. Hitherto, there are currently no studies that addressed the combined effect of all these conditions on the rheological properties and strength development of CPB. At the first stage of this M.A.Sc. study, a series of experimental tests was conducted on fresh CPB in order to determine the combined effect of time, temperature, binder content, and chemical additives on the rheological properties of CPB. These experiments include rheological properties test (yield stress and viscosity), microstructural analysis (thermal analysis and XRD), chemical analysis (pH and Zeta potential), and monitoring tests (electrical conductivity), which were conducted on 125 CPB samples that were mixed and prepared at different temperatures (2oC, 20oC, 35oC) and cured for different curing time (0 hrs., 0.25 hrs., 1 hr., 2hrs, and 4 hrs.). These samples were prepared with different blends of hydraulic binders (PCI, PCI/Slag, and PCI/FA) and contained different dosages of sodium silicate (0%, 0.1%, 0.3%, and 0.5%). The results obtained show that rheology of CPB increases with the progress of curing time. It also increases with the increase in the initial (mixing and curing) temperature and content of sodium silicate. It was also found that the partial usage of slag and FA reduces the rheological properties. However, CPBs containing PCI/FA as binder have lower rheological properties, and thus better flowability, than those that contain PCI/Slag as binder. At the second stage of this M.A.Sc. study, in order to understand the combined effect of time, temperature and sodium silicate content on the strength development of slag-CPB, unconfined compression (UCS) test, microstructural analysis (thermal analysis and MIP), and monitoring tests (electrical conductivity, suction, and volumetric water content) were conducted on 72 CPB samples that were prepared with PCI-Slag as a binder, cured for different times (1 day, 3 days, 7 days, and 28 days) under different curing temperatures of (2oC, 20oC, 35oC), and contained different dosages of sodium silicate (0%, 0.3% and 0.5%). The results obtained at this stage showed that the strength development of slag-CPB increases with the progress of curing time and temperature. It also increases with the increase in the sodium silicate content. Also, the combined effect of high temperature, high dosage of sodium silicate and longer curing time showed significant enhancement in the mechanical strength of slag-CPB. The findings of this M.A.Sc. research will contribute to cost effective, efficient, and safer design of CPB structures in the mine areas. It will also help in minimizing financial loss associated with unsuitable flowability of CPB transported in the CPB delivery system besides reducing the risks of human loss, and the environmental and economic damages associated with the failure of CPB structures.

In this Master Thesis work, the effect of pressure on sintering of cemented carbides is investigated. Special focus hasbeen given to the residual porosity after sintering. It is well known that sintering shrinkage depends on binder phasecontent, grain size, temperature and pressure. Thus 4 different cemented carbides grades were selected. The gradeswere pressed into standard products and TRS (Tensile Rupture Strength) rods with two different shrinkage factors.These were then sintered at different pressures and temperatures. Thereafter the impact of pressure on propertiessuch as Density, Coercivity, Porosity and TRS were analyzed. The observations were further supported with Weibullprobability analysis and fracture surface analysis in SEM.It has been shown that there exists a distinct threshold pressure at which significant reduction in porosity occurs forgiven compacted densities. For 3 out of 4 cemented carbide grades it has been observed that P2 sintering pressure issufficient to meet desired product characteristics. The fourth grade required a minimum sintering pressure of P4 toachieve desired quality criteria. Moreover it has been concluded that an increased sintering pressure increasesmaterial strength, as compared to vacuum sintering, thereby reducing the amount of early failures caused by poresduring TRS test.                                    Keywords: Cemented Carbides, Pressurized Sintering, Tungsten carbide, Porosity, Vacuum sintering, TensileRupture Strength, Weibull analysis, Fracture surface analysis.

A fundamental quantum mechanical modelling approach is used for calculating liquid diffusion parameters in cemented carbides. Up to now, no detailed description of diffusion for alloying elements in a liquid Co matrix is available. Neither are experimental measurements found in the literature for the self- or impurity diffusion in the liquid Co system. State of the art application is the description of gradient formation in cemented carbide systems using DICTRA. In this work it is assumed that diffusion during sintering of cemented carbides takes place mainly in the liquid Co binder phase. With this assumption one can calculate the diffusion coefficient for different alloying elements like W, Ti, N and C in a liquid Co matrix phase. The mean square displacement (MSD) of the diffusing atoms is used to obtain the diffusion coefficients which could be simulated by Ab initio Molecular Dynamics (AIMD). By fitting the computed temperature dependence with the Arrhenius relation one can determine the frequency factor and the activation energy which allows to give a quantitative description of the diffusion. Three methods will be used for validating the data from this work. Available estimated literature values based on calculations (scaling laws, a modified Sutherland equation and classical molecular dynamics) will be used to compare the results in a first instance. The general agreement for diffusion in liquid metals will be done by comparison with experimental data for the liquid Fe system. In a last step, the diffusion values obtained by this work will be used to create a kinetic database for DICTRA. The gradient simulations will be compared with experimentally measured gradients. The AIMD simulations are performed for binary diffusion systems to investigate the diffusion between the liquid Co matrix and one type of alloying element. In a second approach the diffusion for a multicomponent systems with Co, W, Ti and C has been performed. The results from the present AIMD simulations could be shown to be in good agreement with the literature. Only two DICTRA simulations could be performed within the timeframe of this work. Both are predicting a ~3 times bigger gradient zone whereas the initial choice of the labyrinth factor λ = f could be identified as a possible source of disagreement. A labyrinth factor of λ = f2 with the calculated mobility values from the AIMD calculations should give improved results. Although the results from those simulations are not available to this date. The two approaches of the diffusion simulations in the binary and multicomponent system are giving matching results. The non-metallic elements C and N are diffusing two times faster than the fastest metallic element Co. The diffusivity of Ti is slightly lower than Co and W could be identified as the element with the slowest diffusion within the liquid Co matrix. Further investigations of the liquid structure could indicate the tendency to form bonds between C and W and between C and Ti. This gives slowed down diffusion of C in the multicomponent system compared to the diffusion in the binary Co-C system.

This thesis is meant to serve as part of a competence platform for future product development projects at Sandvik Coromant AB, Solid Round Tools Department, Västberga, Sweden. The project objective is to gain generic knowledge of the wear mechanisms that restrict tool lifetime when drilling austenitic stainless steel. Thus, identifying if the weakest link of the tool is located within the coating, the coating adherence or in the strength of the substrate. A theoretical review of the work-piece and tool materials has been conducted as a background, along with definition of tool geometry and process parameters. Furthermore, the review includes chemical and process design effect on mechanical properties of the austenitic stainless steel, TiAlN coatings and cemented carbide substrates. Additionally, the basic principles of the wear mechanisms and wear types that are specific to drilling have been reviewed. During the experimental procedures both solid and exchangeable tip drills from cemented carbide with multilayered PVD TiAlN coatings were tested. Two series of tests were conducted, the first series aimed to identify wear type dependency on cutting speed, focusing on wear of the tool margin. The second test series was performed to map the wear progression depending on distance. Analyses including identification the main wear mechanism, quantification the amount of wear, identify wear location on the tool, crack investigation and WDS analysis of chemical wear. Adhesive coating wear was found on the tool margin at an early stage. The adhesive wear rapidly progressed into a stable intermediate stage. Leaving the substrate exposed and more susceptible to other wear types resulting in crack and oxide layer formation.

Magnetic measurements are useful tools for quality control of cemented carbides. Previous work at Sandvik Mining and Rock Technology has shown that the coercivity increases with increased cooling rate during sintering for a specific grade.  This study aims to investigate why the coercivity changes with the cooling rate and if this is true for other cemented carbide grades as well. Three different cemented carbide grades were sintered with different cooling rates and evaluated with coercivity, Cobalt-magnetic saturation and hardness measurements, and with microscopy and Electron Backscatter Diffraction analysis. It was found that the coercivity increased with increasing cooling rates for the previously studied grade, but not for the two other grades. It was expected that the increased coercivity would indicate a decrease in WC grain size, but the results showed that the WC grain size of the fastest and slowest cooling rate were the same. However, a change in size of the Co areas between the WC grains was found. The fast cooled sample showed smaller Co areas than the slow cooled sample. These Co/WC grain boundaries increase the coercivity. An increased fraction of hcp-Co/fcc-Co was also found for the fast cooled material which also increases the coercivity. No relationship between the hardness and the coercivity or the cooling rate was found.   The contiguity for the different grades was also calculated.  No significant difference in contiguity between the different cooling rates of each material was found but the contiguity values between the different materials differed.  This is probably mainly dependent on the different binder contents of the materials. / Magnetiska egenskaper är en viktig del av kvalitetskontrollen av hårdmetaller.  Tidigare forskning hos Sandvik Mining and Rock Technology har visat att koerciviteten hos en hårdmetallsort ökar med ökad kylhastighet vid sintring.  Målet med den här studien är att undersöka varför koerciviteten ökar med kylhastigheten och om detta även gäller andra hårdmetallsorter.  Tre olika hårdmetallsorter sintrades med olika kylhastigheter undersöktes med mätningar av koercivitet, magnetisk mättnat i koboltfasen och hårdhet,  samt med mikroskopi och Electron Backscatter Diffraction analys. Det  visade  sig  att  koerciviteten  ökade  med  ökad  kylhastighet  för  hårdmetallsorten  som  studerats tidigare, men inte för de andra två sorterna.  En ökad koercivitet förväntas visa på en minskad WC-kornstorlek, men resultaten visar att det långsamt kylda och snabbkylda provet hade samma WC-kornstorlek.  Däremot upptäcktes en ändring av storleken på Co-områdena mellan WC-kornen.  Det snabbkylda provet visade en mindre storlek av Co-områdena jämfört med det långsamt kylda provet. Fler Co/WC-korngränser i det snabbkylda provet leder till en ökad koercivitet.  Fraktionen av hcp-Co/fcc-Co-korngränser ökade också för det snabbkylda provet vilket också ökar koerciviteten. Inget samband mellan hårdheten och koerciviteten eller kylhastigheten upptäcktes.  Beräkning av kontiguiteten för de olika sorterna genomfördes också. Ingen signifikant skillnad i koercivitet mellan de olika kylhastigheterna för the olika sorterna hittades,  men kontiguiteten mellan de olika sorterna varierade. Det beror mest troligt på att dom olika sorterna har olika mängd matrismaterial.

Cemented carbide powder production is the first step in the manufacturing of cemented carbide inserts.The quality of the powder affects the successive process steps in the production of the cemented carbide inserts. The powder is produced by spray drying of a slurry. The slurry consists of polymer, water, ethanol, and dry components. The operating conditions of the spray dryer have been studied greatly to optimize the powder properties but less is known about the influence of the slurry on the powder. This work examines the effect of slurry composition on the cemented carbide powder properties. The work is necessary to predict optimum slurry composition to produce good quality cemented carbide powders. To characterise the powders, flowability, density, particle morphology and hollowness of the powder granules were measured for different slurry compositions. No direct correlation was observed between slurry viscosity and the powder properties but a change in the amount of raw material and organic additives in the slurry affected various powder properties. An optimum slurry composition was obtained which can produce better quality of cemented carbide powder. Additionally, it was found that an increase in slurry viscosity can hinder the spray drying process. / Tillverkning av hårdmetallpulver är det första steget i tillverkningen av hårdmetallinsatser. Pulverkvaliteten påverkar de successiva processstegen vid tillverkningen av hårdmetallinsatserna. Pulvret framställs genom spraytorkning av en uppslamning. Uppslamning består av polymer, vatten, etanol och torra komponenter. Driftförhållandena för spraytork har studerats mycket för att optimera pulveregenskaperna, men mindre är känt om påverkan av uppslamningen på pulvret. Detta arbete undersöker effekten av uppslamningskomposition på egenskaperna för hårdmetallpulver. Arbetet är nödvändigt för att förutsäga optimal uppslamningskomposition för att producera hårdmetallpulver av god kvalitet. För att karakterisera pulvren mättes flytbarhet, densitet, partikelmorfologi och hålighet hos pulvergranulerna för olika uppslamningskompositioner. Ingen direkt korrelation observerades mellan uppslamningsviskositet och pulveregenskaperna men en förändring i mängden råmaterial och organiska tillsatser i uppslamningen påverkade olika pulveregenskaper. En optimal uppslamningskomposition erhölls som kan ge bättre kvalitet på hårdmetallpulver. Dessutom fann man att en ökning av uppslamningsviskositeten kan hindra spraytorkningsprocessen.

Bei der Rekonstruktion des durch Krankheit oder Trauma geschädigten Hüftgelenkes hat sich der Ersatz des Gelenkes durch eine totale Endoprothese heute allgemein durchgesetzt. Dabei hat unter Beachtung einer differenzierten Indikationsstellung sowohl die zementierte als auch die zementfreie Technik ihre Anwendungsberechtigung. Das Problem der dauerhaften Verankerung der zementfreien Hüftendoprothese ist jedoch trotz ständiger Weiterentwicklung von Operationstechnik, Implantatdesign und Werkstoffen bis heute nicht abschließend gelöst. Die häufigste Versagensursache ist dabei die aseptische Schaftlockerung, die mit Veränderungen des knöchernen Lagers einhergeht. Mit der Osteodensitometrie existiert eine Technik, die eine schnelle, nichtinvasive und quantitative Beurteilung der Knochenmasse erlaubt. In der vorliegenden Querschnittsstudie wurden 95 Zweymüller-Schaftimplantate zwei, vier bzw. sechs Jahre nach Implantation untersucht. Dabei wurden die Ergebnisse der klinischen Untersuchung und der konventionellen a.p. Röntgenaufnahme den mit Hilfe der DEXA-Technik ermittelten Knochendichteänderungen am Femur gegenübergestellt. Der Vergleich von Knochendichteänderungen in einzelnen Femurabschnitten in Abhängigkeit von der Implantationsdauer läßt Rückschlüsse auf das Schaftdesign zu. / When hip function is several impaired by disease or trauma, total hip replacement is preferred treatment of choice today. The consideration of a differentiated position of indication justifies both - the application of the cemented as well as the cement free technique. But despite of constant further development of operation techniques, design of implantation and the used materials is the problem of a permanent embodiment of the non-cemented hip prosthesis till today not finally solved. The aseptic relaxation of the stem is the most frequent reason for failure. This is accompanied by changes of the osseous bed. With the osteodensitometry exists a technique that makes a fast, non-invasive and quantitative assessment of the bone mass possible. In this present cross-section study 95 Zweymüller-stem-implants were examined two, four and six years after the implantation. The results of the clinical examination and the results of the conventional X-ray picture were compared with the changes of the thigh femur bone density that were ascertained by the DEXA-technique. The comparison of changes of the bone density in single femur sections in dependence on the duration of the implantation allows one to draw conclusions from the design of the stem.

Cada vez mais freqüente, a utilização de técnicas tradicionais da engenharia geotécnica depara-se com obstáculos de caráter econômico e ambiental. A técnica do solo-cimento tornase atrativa quando o melhoramento das propriedades do solo do local constitui-se em uma alternativa de projeto. A técnica de tratamento de solos com cimento encontra aplicação, por exemplo, na construção de bases para pavimentos, na proteção de taludes em barragens de terra, como camada de suporte para fundações superficiais, como remediação de solos contaminados e como barreiras de contenção de contaminantes. Desta forma, esta tese tem por objetivo analisar a influência da quantidade de cimento, da porosidade e da umidade de moldagem sobre o comportamento físico e químico de um solo argiloso artificialmente cimentado e contaminado. O programa experimental consiste em caracterizar os materiais utilizados, analisar fisicamente as misturas solo-cimento e solo-cimento-contaminante, através de ensaios de resistência à compressão simples, medidas de sucção e condutividade hidráulica. Quimicamente serão realizados ensaios de lixiviação em coluna e análises químicas e físico-químicas do lixiviado. Os resultados, quanto à caracterização, apresentam um material argiloso, oriundo de rochas riodacitos (riolito/dacito); quanto à resistência à compressão simples houve um aumento de resistência com o aumento da quantidade de cimento e com o aumento do peso especifico de compactação; quanto ao solo contaminado e cimentado ocorreu o mesmo comportamento, porém, com queda de resistência. A condutividade hidráulica obteve um decréscimo quando aumentado o peso especifico de moldagem, tanto para solo-cimento como para solo-cimento-contaminante. Para as análises químicas, a partir do ensaio de lixiviação, contatou-se redução de parâmetros de contaminação com a adição de cimento, principalmente com o aumento significativo do pH, devido ao aumento da quantidade de cimento. Concluiu-se que a quantidade de cimento e a diminuição da porosidade ocorrida pela maior densificação influenciam em ganho de resistência, à uma baixa permeabilidade e à uma baixa concentração de contaminante no lixiviado. / More and more the use of traditional techniques of the geotechnical engineering comes across obstacles of economic and environmental character. The technique of the soil-cement becomes attractive when the improvement of the properties of the local soil constituted in a project alternative. The technique of treatment of soils with cement finds application, for instance, in the construction of bases for pavements, in the protection of talus in land dams, as support layer for superficial foundations, as remediation of polluted soils and as barriers of contention of pollutants. This way, this theory has as objective to analyze the influence of the amount of cement, of the porosity and of the molding humidity over the physical and chemical behavior of a loamy soil artificially cemented and polluted. The experimental program consists of characterizing the used materials, to analyze the mixtures soil-cement and soil-cement-pollutant physically, through resistance samples to the simple compression, suction measures and hydraulic conductivity. The lixiviation samples will be chemically accomplished in column and chemical and physiochemical analyses of the lixiviated. The results, according to the characterization, present a loamy material, originating from rocks rhyodacite (rhyolite/dacite); according to the resistance to the simple compression there was a resistance increase with the rise of the amount of cement and with the increase of the weight specific of compaction; as for the polluted soil and cemented happened the same behavior, however, with resistance fall. The hydraulic conductivity suffered a decrease when increased the specific weight of molding, for soil-cement and for soil-cement-pollutant. (Continue For the chemical analyses, starting from the lixiviation samples, it was reached a reduction of parameters of contamination with the cement addition, mainly with the significant increase of the pH, due to the increase of the amount of cement. It was concluded that the amount of cement and the decrease of the porosity happened by the largest densification influence in resistance adding, as well as they provide a low permeability and a low pollutant concentration in the lixiviated. / Cada vez más la utilización de técnicas tradicionales de la ingeniería geotécnica se depara con obstáculos de carácter económico y ambiental. La técnica del suelo-cemento se vuelve atractiva cuando el mejoramiento de las propiedades del suelo local se constituye en una alternativa de proyecto. La técnica de tratamiento de suelos con cemento encuentra aplicación, por ejemplo, en la construcción de bases para pavimentos, en la protección de taludes, en presas de tierra, como camada de soporte para fundaciones superficiales, como remediación de suelos contaminados y como barreras de contención de contaminantes. Esta tesis tiene por objetivo analizar la influencia de la cantidad de cemento, de la porosidad y de la humedad del molde, sobre el comportamiento físico y químico de un suelo arcilloso artificialmente cementado y contaminado. El programa experimental consiste en caracterizar los materiales utilizados, analizar físicamente las mezclas suelo-cemento y suelo-cementocontaminante a través de ensayos de resistencia a compresión simple, medidas de succión y conductividad hidráulica. Químicamente serán realizados ensayos de lixiviación en columna y análisis químicos y físico-químicos del lixiviado. Los resultados, con respecto a la caracterización, presentan un material arcilloso, oriundo de rocas riodacitos (riolito/dacito). En cuanto a la resistencia el aumento de la misma es directamente proporcional al aumento de la cantidad de cemento y del peso especifico de compactación, referente al suelo contaminado y cementado ocurrió el mismo comportamiento, pero con disminución de resistencia. La conductividad hidráulica obtuvo una reducción cuando se produjo el aumento del peso específico, tanto para suelo-cemento como para suelo-cemento-contaminante. Para los análisis químicos, a partir del ensayo de lixiviación, se constato reducción de parámetros de contaminación con la adición de cemento, principalmente con el aumento significativo del pH. Se concluyó que la cantidad de cemento y la disminución de la porosidad ocurrida por l mayor compampactacion influencio en el aumento de resistencia, asi como porporciono baja permeabilidad y baja concentración de contaminante en el lixiviado.

Thema dieser Arbeit ist eine experimentelle Untersuchung zur Verbesserung der tribologischen Eigenschaften von Hartmetallen auf der Basis von Wolframkarbid– Kobalt unter Benutzung von Ionen–Implantation in Kombination mit den hierbei auftretenden Struktur– und Phasen–Änderungen. Die vorliegende Arbeit unterscheidet sich von allen anderen bisherigen Arbeiten besonders durch (1.) die detaillierte Analyse der mikroskopischen Veränderungen und durch (2.) deren Verknüpfung mit der Änderung der tribologischen Eigenschaften des Materials.