The present dissertation is motivated by the search for alternatives of lead-free soldering by nanoparticles of metals and their alloys. The research focuses on the possibility of replacing lead-free solders by nanoparticles. This issue is currently being addressed by the use of lead-free solders but their properties are not entirely equivalent to properties of lead-tin based alloys. The theoretical part of the dissertation first summarizes up-to date knowledge on the development of lead-free alloys currently used for soldering in the electronics. The work compares these lead-free solder candidates with previously used Pb-Sn alloys. The second section of the theoretical part is devoted to nanotechnology that offers possible solutions of problems associated with the use of lead-free solders. The text contains a description of the properties of nanocrystalline materials in comparison with those of compact alloys having the same chemical composition. The possibility of preparation of nanoparticles and potential problems associated with small particle sizes are also presented. Introduction of the experimental part focuses on the preparation of nanoparticles of pure metals and alloys by chemical and physical ways as well as on an instrumentation for characterisation and analysis. Attention is focused on the silver in nanoparticle form that exhibits the low temperature sintering effect, which is thermally activated by decomposition of oxide envelope covering the Ag nanoparticles. This factor is critical for low-temperature sintering and thus also for possible future applications. The thermal effects of the low sintering process were studied by methods of thermal analysis. The preparation of the Cu / Ag nano / Cu joints was carried out in-situ in inert atmosphere and under the action of atmospheric oxygen. In both cases varying conditions of thermal treatment were used. The cross sections of the prepared joints were then used for the metallographic analysis of the local mechanical properties of the resulting silver layer, for the chemical composition evaluation of the resulting layers of the joint, and for the microstructure study. Strength characteristics are represented by testing shear strength of individual joints.

Additively manufactured (AM) 316L and 17-4PH stainless steel parts, concretely made by laser powder bed fusion (L-PBF), are characterized and micro-mechanical properties of those steels are analyzed. This study also explored and extended to proton irradiation and small-scale mechanical testing of those materials, to investigate how irradiation affects microstructural evolution and thus mechanical properties at the surface level, which could be detrimental in the long term in nuclear applications. In-depth anisotropy analysis of L-PBF 316L stainless steel parts with the variations of volumetric energy density, a combined study of nanoindentation with EBSD (electron backscatter diffraction) mapping is shown to be an alternative methodology for enriching qualification protocols. Each grain with a different crystallographic orientation was mapped successfully by proper indentation properties. <122> and <111> oriented grains displayed higher than average indentation modulus and hardness whereas, <001>, <101>, and <210> oriented grains were found to be weaker in terms of indentation properties. Based on an extensive nanoindentation study, L-PBF 17-4 PH stainless steels are found to be very sensitive to high load rates and irradiation further escalates that sensitivity, especially after a 0.25 s-1 strain rate. 3D porosity measurement via X-ray microscope ensures L-PBF stainless steel parts are of more than 99.7% density and could be promising for many industrial applications. High percentages of increment of nanohardness, maximum theoretical shear strength, and yield strength were observed due to proton irradiation of 5 um damage depth on the surface of 17-4 PH steel parts. Small-scale mechanical testing of irradiated AM nuclear stainless steels such as 17-4 PH was carried out and investigated by micro-compression of FIB fabricated pillars of different sizes of diameter. Irradiated 17-4 PH materials have never been investigated by this kind of testing procedure to asses the stress-strain characteristics of micro-scale volumes and to explore the structure-property relationship. Both as-built and irradiated AM 17-4 PH micropillars exhibited step-ups in the early stage of load-displacement curves with a varying number of slip bands intermittently formed throughout the pillar volume while compressed by the uniaxial load. As for the radiation-damaged zone, micropillars displayed lesser slip bands compared to as-built parts as irradiation damage creates an obstacle to dislocations movement and hence hardening. It requires higher loads to initiate plastic deformation as dislocation must overcome irradiation-induced obstacles for the slip to occur and localization of strain without increasing the load for a certain amount of time during the test. Proton irradiation effects on the compressive mechanical properties of AM 17-4 PH stainless steel parts depending on the volumetric energy density (VED) used during the parts' fabrication process. On as-built parts, compressive yield strength varied from 107.27 MPa to 150.70 MPa and it was in the range of 133.43 MPa to 244.57 MPa under irradiated conditions. All 2 μm pillars were fabricated as their height falls within the radiation damage depth of 5 μm. It was expected to generate the highest yield strength and tensile strength due to the radiation hardening effect as discussed earlier. Yield and tensile strength were found to be the highest as expected as of 244.57 MPa and 375.08 MPa in irradiated 17-4 PH sample 1 (VED = 54.76 J/mm3). Samples with lower VED exhibited better micro-mechanical compressive responses than higher VED AM 17-4 PH parts in both as-built and irradiated conditions.

Due to their therapeutic applications such as radical scavenging, MRI contrast imaging, Photoluminescence imaging, drug delivery, etc., nanoparticles (NPs) have a significant importance in bio-nanotechnology. The reason that prevents the utilizing NPs for drug delivery in medical field is mostly due to their biocompatibility issues (incompatibility can lead to toxicity and cell death). Changes in the surface conditions of NPs often lead to NP cytotoxicity. Investigating the role of NP surface properties (surface charges and surface chemistry) on their interactions with biomolecules (Cells, protein and DNA) could enhance the current understanding of NP cytotoxicity. Hence, it is highly beneficial to the nanotechnology community to bring more attention towards the enhancement of surface properties of NPs to make them more biocompatible and less toxic to biological systems. Surface functionalization of NPs using specific ligand biomolecules have shown to enhance the protein adsorption and cellular uptake through more favorable interaction pathways. Cerium oxide NPs (CNPs also known as nanoceria) are potential antioxidants in cell culture models and understanding the nature of interaction between cerium oxide NPs and biological proteins and cells are important due to their therapeutic application (especially in site specific drug delivery systems). The surface charges and surface chemistry of CNPs play a major role in protein adsorption and cellular uptake. Hence, by tuning the surface charges and by selecting proper functional molecules on the surface, CNPs exhibiting strong adhesion to biological materials can be prepared. By probing the nanoscale interaction forces acting between CNPs and protein molecules using Atomic Force Microscopy (AFM) based force-distance (F-D) spectroscopy, the mechanism of CNP-protein adsorption and CNP cellular uptake can be understood more quantitatively. The work presented in this dissertation is based on the application of AFM in studying the interaction forces as well as the mechanical properties of nanobiomaterials. The research protocol employed in the earlier part of the dissertation is specifically aimed to understand the operation of F-D spectroscopy technique. The elastic properties of thin films of silicon dioxide NPs were investigated using F-D spectroscopy in the high force regime of few 100 nN to 1 µN. Here, sol-gel derived porous nanosilica thin films of varying surface morphology, particle size and porosity were prepared through acid and base catalyzed process. AFM nanoindentation experiments were conducted on these films using the F-D spectroscopy mode and the nanoscale elastic properties of these films were evaluated. The major contribution of this dissertation is a study exploring the interaction forces acting between CNPs and transferrin proteins in picoNewton scale regime using the force-distance spectroscopy technique. This study projects the importance of obtaining appropriate surface charges and surface chemistry so that the NP can exhibit enhanced protein adsorption and NP cellular uptake.

[pt] Durante a exploração e produção de petróleo, dificuldades operacionais precisam ser superadas na injeção de CO2 para aumento da produção. Na presença de água, o CO2 reage e forma o H2CO3, que pode vir a corroer o aço carbono presente nos dutos flexíveis. Diversos fatores influenciam no processo corrosivo, entre eles a pressão parcial de CO2, a temperatura, pH do meio e a relação volume de solução/área metálica exposta (V/A). Desta forma, o objetivo deste trabalho foi avaliar a composição e propriedades mecânicas dos produtos de corrosão depositados sobre a superfície do aço carbono 1080 imersos em água do mar sintética, a temperatura de 40 graus C, durante 15 e 121 dias. Para avaliar a influência da pressão parcial de CO2, os ensaios foram realizados a 1, 10 e 20 bar de CO2, já para avaliar a influência da relação V/A, os ensaios foram realizados a 1 mL.cm-2 e 20 mL.cm-2 . As taxas de corrosão foram determinadas utilizando o método gravimétrico, as caracterizações dos produtos de corrosão foram realizadas por Microscopia Óptica (MO), Microscopia Eletrônica de Varredura (MEV), Espectroscopia de Energia Dispersiva (EDS) e Dispersão de Raios X (DRX). Adicionalmente, foi utilizada a Nanoindentação para determinar as propriedades mecânicas do filme formado. A partir da MO, foi identificado a formação de dois filmes em quase todas as condições estudadas. Ao avaliar a influência da pressão, não foram observadas variações significativas na taxa de corrosão. Já os resultados obtidos para avaliar o efeito da relação V/A, foi possível concluir que o ambiente confinado reduz significativamente a taxa de corrosão. Ao avaliar as propriedades mecânicas dos filmes, foi possível observar que em todos os casos, a dureza e o módulo de elasticidade são menores no filme interno quando comparados ao filme externo. Isso pode estar relacionado a formação de uma camada externa mais compacta, constituída predominantes por pequenos grãos de FeCO3, conforme os resultados obtidos através do MEV e DRX / [en] During oil exploration and production, operational difficulties need to be overcome in CO2 injection to increase production. In the presence of water, CO2 reacts and forms H2CO3, which can corrode the carbon steel present in flexible pipes. Several factors influence the corrosive process, including the partial pressure of CO2, the temperature, pH of the medium and the volume of solution/exposed metallic area (V/A) ratio. Thus, the objective of this work was to evaluate the composition and mechanical properties of the corrosion products deposited on the surface of carbon steel 1080 immersed in synthetic sea water, at a temperature of 40 C degrees, for 15 and 121 days. To evaluate the influence of the partial pressure of CO2, the tests were carried out at 1, 10 and 20 bar of CO2, and to evaluate the influence of the V/A ratio, the tests were carried out at 1 mL.cm-2 and 20 mL. cm-2 . Corrosion rates were determined using the gravimetric method, characterizations of corrosion products were performed by Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-Ray Scattering (XRD). Additionally, Nanoindentation was used to determine the mechanical properties of the formed film. From the OM, the formation of two films was identified in almost all conditions studied. When evaluating the influence of pressure, no significant variations in the corrosion rate were observed. As for the results obtained to evaluate the effect of the V/A ratio, it was possible to conclude that the confined environment significantly reduces the corrosion rate. When evaluating the mechanical properties of the films, it was possible to observe that in all cases, the hardness and the elastic modulus are lower in the inner film when compared to the outer film. This may be related to the formation of a more compact outer layer, consisting predominantly of small FeCO3 grains, according to the results obtained through SEM and XRD.

Die Anwendung des Verfahrens der inversen Parameteridentifikation auf die Nanoindentation mit einer neuen Materialklasse (amorphe Legierungen) ist Hauptgegenstand der vorliegenden Arbeit. Um die Methode auf ihre Zuverlässigkeit hin zu überprüfen, werden darüber hinaus die drei Härtevergleichsplatten HV240, HV400 und HV720 sowie das oxidische Glas BK7, deren Nanoindentationsmessungen von Dipl.-Ing. André Clausner schon zu einem früheren Zeitpunkt vorgenommen wurden, zur Berechnung herangezogen. Die Auswahl der Materialien erfolgte so, dass diese einen möglichst großen Bereich von Y abdecken, von BK7 bis hin zu HV240. Damit soll gezeigt werden, dass das Verfahren der inversen Parameteridentifikation für einen großen Bereich von natürlich vorkommenden Materialien genutzt werden kann. Der Schwerpunkt liegt dabei auf der Bestimmung des Fließverhaltens, das durch die Parameter Fließgrenze1 Y und Verfestigungsexponent n erfolgt. Ziel ist es, in Zukunft auf weitere Experimente, die bisher zur Bestimmung der mechanischen Materialeigenschaften genutzt wurden und häufig zur Zerstörung der Proben führten, verzichten zu können. Für viele Gläser, z.B. BK7, sind derartige zerstörende Versuche nicht anwendbar, weil spröde Materialien splittern statt plastisch zu fließen. Dieser Arbeit liegt die Methode der Finiten-Elemente zugrunde, um eine inverse Parameteridentifikation zu realisieren. Sie wird hier eingesetzt, weil es sich bei plastischer Verformung um einen nichtlinearen Prozess2 handelt, der analytisch nicht mehr geschlossen gelöst werden kann. Die Simulationssoftware ANSYS R und ein Optimierungsmodul (SPC-OPT) der Fakultät für Maschinenbau dienen zur Berechnung. Bei der Simulation werden dabei ein zweidimensionales Modell und ein realitätsnahes dreidimensionales Modell eingesetzt.

Le besoin pressant de substitution du plomb dans les alliages de soudure a conduit à une introduction très rapide de nouveaux alliages sans plomb dont la connaissance en termes de comportement n'est pas assez approfondie. En effet, d'autres problématiques sont apparues (l'augmentation de la température du procédé de soudage, trop grand choix disponible dans les alliages alternatifs) alors que les problèmes relatifs aux alliages actuels sont restés sans réponse (le changement incessant de la microstructure des alliages de soudure, la méthodologie empirique prédisant la durée de vie). Tous les paramètres cités ci-dessus modifient la stabilité et la fiabilité des performances spécifiques de l'alliage de soudure et par conséquence, de tout le module électronique.De plus, avec la miniaturisation de l'électronique et les conditions d'environnement de plus en plus sévères, ces obstacles deviennent critiques et les solutions actuelles ne sont plus compatibles. Les demandes de ce marché deviennent donc de plus en plus strictes en termes de prédiction de durée de vie et de contrôle de fiabilité.L'objectif de ce projet est de comprendre et de concevoir une nouvelle formulation d'alliage sans plomb afin de développer une alternative à l'alliage plombé haute température et un alliage pour les applications haute fiabilité et en accord avec les directives gouvernementales. Des approches expérimentales avancées comme la nano-indentation, le suivi de l'évolution de la microstructure par SEM et par EDS mapping, l'étude des effets du vieillissement thermique sur la croissance de la taille des grains avec de la lumière croisée polarisée de microscopie optique etc seront utilisées pour développer un alliage sans plomb qui convienne aux exigences des applications automobile et pipeline / The urgent need for removing lead from solder alloys led to the very fast introduction of lead-free solder alloys without a deep knowledge of their behaviour. As a consequence, additional issues raised (increased thermally induced problems during soldering process, a too wide range of possible available alternative alloy formulations), while problems related to current solder alloys remained unsolved (the constant change of the solder alloy microstructure, empirical predicting lifetime methodology). All the above mentioned issues alter stability and reliability of the application specific performances of the solder alloy, and subsequently of the whole electronic module. These problems become critical and are no longer compatible, as the market goes towards miniaturization and harsh environment conditions. These market trends now require stricter life time prediction and reliability control. Objective of this project is to understand and design a novel lead-free solder formulation to develop a potential alternative to lead-based high temperature melting point solder for high reliability requirements and in accordance with governmental directives. An advanced experimental approach like nanoindentation, microstructure evolution with SEM and EDS mapping, thermal aging effects on continuous grain size growth with cross polarized light of optical microscopy etc. would be implemented to develop doped-SAC lead-free solders for the best-fit to requirements in automotives and pipelines applications

Thermoelectric (TE) ZrNiSn samples with a half-Heusler atomic structure were synthesized by mechanical alloying (MA) and consolidation by either Spark Plasma Sintering (SPS) or hot pressing (HP). X-Ray diffraction patterns of as milled powders and consolidated samples were compared and analyzed for phase purity. Thermal conductivity, electrical conductivity and Seebeck coefficient are measured as a function of temperature in the range 300 K to 800 K and compared with measurements reported for high temperature solid state reaction synthesis of this compound. HP samples, compared to SPS samples, demonstrate increased grain growth due to longer heating times. Reduced grain size achieved by MA and SPS causes increased phonon scattering due to the increased number of grain boundaries, which lowers the thermal conductivity without doping the base system with addition phonon scattering centers. Mechanical characterization of the samples by microindentation and depth sensing indentation for hardness and elastic modulus will be discussed.

<p> This dissertation describes the recent advancements in micromechanical testing that inform how deformation mechanisms in austenitic stainless steels (SS) are affected by the presence of irradiation-induced defects. Austenitic SS is one of the most widely utilized structural alloys in nuclear energy systems, but the role of irradiation on its underlying mechanisms of mechanical deformation remains poorly understood. Now, recent advancement of microscale mechanical testing in a scanning electron microscope (SEM), coupled with site-specific transmission electron microscopy (TEM), enables us to precisely determine deformation mechanisms as a function of plastic strain and grain orientation.</p> <p> </p> <p>We focus on AISI 304L SSs irradiated in EBR-II to ~1-28 displacements per atom (dpa) at ~415 °C and contains ~0.2-8 atomic parts per million (appm) He amounting to ~0.2-2.8% swelling. A portion of the specimen is laser welded in a hot cell; the laser weld heat affected zone (HAZ) is studied and considered to have undergone post-irradiation annealing (PIA). An archival, virgin specimen is also studied as a control. We conduct nanoindentation, then prepare TEM lamellae from the indent plastic zone. In the 3 appm He condition, TEM investigation reveals nucleation of deformation-induced <i>α</i>’ martensite in the irradiated specimen, and metastable <i>ε</i> martensite in the PIA specimen. Meanwhile, the unirradiated control specimen exhibits evidence only of dislocation slip and twinning; this is unsurprising given that alternative deformation mechanisms such as twinning and martensitic transformation are typically observed only near cryogenic temperatures in austenitic SS. Surface area of irradiation-produced cavities contribute enough free energy to accommodate the martensitic transformation. The lower population of cavities in the PIA material enables metastable <i>ε</i> martensite formation, while the higher cavity number density in the irradiated material causes direct <i>α</i>’ martensite formation. In the 0.2 appm He condition, SEM-based micropillar compression tests confirm nanoindentation results. A deformation transition map with corresponding criteria has been proposed for tailoring the plasticity of irradiated steels. Irradiation damage could enable fundamental, mechanistic studies of deformation mechanisms that are typically only accessible at extremely low temperatures. </p>

A qualidade óssea em grandes animais é avaliada pela densidade mineral óssea (DMO) utilizando a técnica de densitometria óptica em imagens radiográficas; o objetivo desse trabalho foi avaliar e comparar a qualidade óssea baseada na microarquitetura de uma forma inédita. Foram selecionados 20 bovinos, 10 da raça Canchim e 10 da raça Nelore, com controle dos processos biológicos e bioquímicos do nascimento até o abate aos 24 meses de idade, antes de entrarem na fase adulta. O osso metatarsal foi escolhido por suportar maior carga e amostras da diáfise do osso cortical seco foram obtidas. A avaliação da estrutura cristalina de ossos metatarsais secos foi realizada utilizando difração de raios X com a aplicação do método de refinamento de Rietveld, avaliando parâmetros de rede, tamanho de cristalito e microdeformação. A técnica de nanoindentação permitiu avaliar os módulos de elasticidade e valores de nanoindentação. A composição química razão cálcio e fósforo do material, resistência à deformação plástica, valores de microdureza, e imagens de microscopia eletrônica de varredura e microscopia óptica foram realizadas. A comparação entre os resultados das duas raças, Canchim e Nelore, dos valores de parâmetros de rede da estrutura cristalina da hidroxiapatita, tamanho de cristalito, microdeformações, relação cálcio e fósforo, microdurezas Vickers/Knoop, nanodureza Vickers e módulo de elasticidade indicaram que a qualidade óssea das raças Canchim e Nelore é estatisticamente semelhante para 30% dos parâmetros estudados e que para os demais 70% dos parâmetros estudados não há semelhança. / The bone quality in large animals is evaluated by bone mineral density (BMD) using the optical densitometry technique in radiographic images; The objective of this study was to evaluate and compare bone quality based on microarchitecture unpublished. Twenty bovines were selected, 10 from the Canchim breed and 10 from the Nelore breed, with control of the biological and biochemical processes from birth to slaughter at 24 months of age, before entering adulthood. The metatarsal bone was chosen because it supported higher load and samples of the diaphysis of the dry cortical bone were obtained. The evaluation of the crystalline structure of dry metatarsal bones was performed using X - ray diffraction with the application of the Rietveld refinement method, evaluating network parameters, crystallite size and microdeformation. The nanoindentation technique allowed to evaluate the modulus of elasticity and nanoindentation values. The chemical composition calcium and phosphorus ratio of the material, resistance to plastic deformation, values of microhardness, and scanning electron microscopy images and optical microscopy were performed. The comparison between the results of the two races, Canchim and Nelore, of the network parameter values of the hydroxyapatite crystal structure, crystallite size, microdeformations, calcium and phosphorus ratio, Vickers/Knoop microhardness, Vickers nanodness and modulus of elasticity indicated that Quality of the Canchim and Nelore races is statistically similar for 30% of the studied parameters and that for the ofter 70% of the studied parameters there is no similarity.

La technologie de projection plasma sous basse pression a attiré l’attention de nombreux chercheurs comme une nouvelle technique qui permet d’établir un pont entre la projection thermique conventionnelle et le dépôt physique en phase vapeur. Ainsi, cette technologie étend les limites de projection thermique classique et augmente également la vitesse de croissance des dépôts par rapport aux procédés PVD ou CVD classiques. Cette technique peut évaporer totalement ou partiellement les poudres injectées et mener à la réalisation de revêtements à microstructure colonnaire et/ou plus denses, difficiles à réaliser avec des procédés de projection thermique conventionnels. La projection plasma de suspension a été effectuée pour la première fois sous basse pression. L’injection axiale de suspension avec une torche tri-cathodes permet d’augmenter l’échange enthalpique entre le jet de plasma et les poudres après l’évaporation du solvant. La spectroscopie à l’émission optique (OES) a été utilisée pour estimer la température électronique et vérifier l’existence de phase vapeur d’YSZ dans le jet de plasma. Finalement, des revêtements plus denses furent réalisés (comparés à ceux préparés par projection plasma de suspension à pression atmosphérique présentant des particules fondues, agglomérées et de la condensation de vapeur. Des tests de nano-indentation instrumentée ont été effectués sur la surface polie des dépôts réalisés. Les résultats montrent des valeurs de 5,8 GPa pour la dureté et 114,5 GPa pour le module d’élasticité, augmentant de 61% et 31%, respectivement, en comparaison avec les valeurs obtenues par SPS sous atmosphère ambiante. Les essais de projection de poudre YSZ agglomérée ont été réalisés avec une torche F4-VB dans le but de synthétiser une phase vapeur d’YSZ. On observe que les dépôts peuvent se former derrière les échantillons en céramique, sans vis-à-vis du plasma, par condensation de vapeur. En face de cette torche, des revêtements composites ont été obtenus par un mélange de poudres fondues et condensation de vapeur, simultanément. Cependant la quantité de phase vapeur est très faible dans le jet de plasma. Pour comprimer ce jet sous basse pression et afin d’améliorer l’échange d’enthalpie entre le jet de plasma et les poudres injectées, une buse rallongée a été mise en place sur la torche F4-VB. Les revêtements présentent ainsi une microstructure plus dense. Ceci est attribué à la haute vitesse des particules fondues vers le substrat suite à l’utilisation de la buse modifiée. Ce type de revêtement montre une valeur maximale de microdureté Vickers de 1273 Hv100 g. Par ailleurs, la réalisation de dépôts de carbures a été effectuée. Les résultats montrent la possibilité de former des carbures par projection plasma sous basse pression. Les revêtements composites (TiC/Ti) sont déposés par projection plasma réactif sous basse pression en utilisant le méthane comme gaz porteur. La température électronique Te calculée est d’environ 6200 K selon les résultats d’OES, ce qui est supérieur à la température d’ébullition du Ti et de TiC. Le revêtement de Ti pur présente une microstructure dense alors que TiC/Ti présente une microstructure lamellaire. Cependant, la quantité de TiC dans les revêtements est d’environ 20 vol.%. La microdureté Vickers, effectuée sur surface polie, a tendance à diminuer de 846±152 à 773±86 Hv100 g avec l’augmentation de la distance de projection. / As a new technology, the very low pressure plasma spraying has attracted attentions of many researchers, making it possible to establish a bridge between the conventional atmospheric plasma spraying (APS) and the vapor deposition (PVD or CVD). As a result, this new technology enlarges the limitation of APS and increases the deposition rate in comparison with the PVD or CVD. It is possible to evaporate partially the injected material and even evaporate completely and finally realize the columnar or dense coatings from the vapor or the mixture of vapor and liquid. The suspension plasma spraying is performed for the first time at low pressure. Taking consideration of the configuration of the three-cathode torch, the axial injection of the suspension is conducted which can increase the enthalpy change between the plasma jet and the sprayed material. The data of optical emission spectroscopy (OES) could be used to calculate the electron temperature and verify the existence of vapor of YSZ in the plasma jet. Finally, the dense coating was prepared by suspension plasma spraying at low pressure, which is composed of the melted particles, the agglomerated particles and the vapor deposition. The test of nano-indentation is conducted on the polished surface. It shows a value of 5.8 GPa for the microhardness and 114.5 GPa for the elastic modulus, increasing 61% and 31%, respectively, compared with the values obtained by SPS in the ambient atmosphere. In this study, another torch F4-VB is also conducted even of it has a low power in compared with that of O3CP torch. The powder feed rate is reduced to about 1.5 g·min-1 to achieve the vapor of YSZ taking the low power input of the torch into consideration. The columnar structure coating is realized from vapor deposition out of line of sight of projection upon the ceramic tubes. The composite structure coating is deposited by the mixture of melted particles and the vapor deposition simultaneously in front of this torch. But the quantity of vapor of YSZ is low in plasma jet. In order to compress the larger plasma jet and then improve the enthalpy change between the plasma jet and sprayed particles, an extended nozzle is prepared. It shows that the coating has a dense structure, which can be attributed to higher velocity of the melted powders. The coating shows a maximum value of microhardness Vickers up to 1273 Hv100 g. The composite coating of TiC/ Ti is realized by reactive plasma spraying using the methane as the carrier gas. The electron temperature Te is calculated to be 6200 K, which is over the boiling point of TiC and Ti. The coating Ti shows a dense structure and the composite coating TiC/Ti shows a lamellar structure. But the quantity of TiC in the composite coating is very low, about 20 vol.%. The Vickers microhardness is performed on the polished surface. It shows a decreasing tendency from 846 ± 152 to 773 ± 86 Hv100g with the increase of spraying distance. The tribological test is also implemented showing a high value of the coefficient of friction of 0.78 to 0.85, which can lead to a high abrasion. In order to synthesize a larger quantity of TiC in the composite coating, a higher power input torch should be put into action in the future.