Littérature scientifique sur le sujet « Inconel625 - Al2O3 »

In solar thermal storage system, the mixed chloride molten salt with the higher conversion efficiency than a single molten salt, but they are more corrosive than the often used nitride molten salts. In the presents work, aluminide and chromate coating were prepared on the surface of Inconel625 alloy by thermal packing method. The corrosion behaviors of thermal diffusion coating on the surface of Inconel625 alloy in mixed molten salts at 900°C were studied by using XRD and SEM equipped with EDS in the present work. The results showed that both of the two thermal diffusion coatings have sever corrosion in the mixed chloride molten salts, but thermal diffusion Al coating in the mixed chloride molten salt corrosion is more serious than thermal diffusion Cr coating, because Cr2O3is more easily dissolved in the molten salt than Al2O3.

A Cr3C2-Al2O3-NiCr composite coating was prepared on an INCONEL600 alloy surface through high-velocity oxygen-fuel spraying followed by further processing through high-energy shot peening to create the composite coating. The microhardness and friction properties of the composite coating are analyzed by a microhardness tester and reciprocating friction tester. The microscopic structure and wear trace of the composite coating were analyzed by scanning electron microscope (SEM). The element distribution of the coating was analyzed by energy-dispersive spectroscopy (EDS). The porosity of the coating was detected by industrial CT. The phase and residual stress of the coating were tested by X-ray diffraction (XRD). The electrochemical corrosion and friction wear performance of the samples under different surface states were discussed. The results showed that the compactness of the coating was improved and the porosity was significantly reduced after high-energy shot peening. The high-energy shot peening did not alter the phase composition of the coating but introduced residual compressive stress. The microhardness of theCr3C2-Al2O3-NiCr high-velocity oxygen-fuel coating can reach 2.9 times that of the INCONEL600 substrate, and the hardness of the coating after high-energy shot peening can reach 3.9 times of that of the substrate. After high-energy shot peening, the corrosion resistance of the coating in HCl solution is improved. Compared with the INCONEL600 substrate, the friction coefficient and calculated wear rate of the Cr3C2-Al2O3-NiCr high-velocity oxygen-fuel coating decrease by 62.5% and 79.6%, respectively. After high-energy shot peening, the friction coefficient and calculated wear rate of the coating decrease by 75% and 98.7%, respectively.

Abstract In this study, Inconel625+30%Al2O3 (IN30AL) blended powders were sprayed on a commercially used boiler steel ASTM SA210 GrA1 using high-velocity oxy-fuel approach (HVOF). The microstructure, mechanical properties and elevated temperature erosion behavior of post-processed coatings and as-sprayed IN30AL coatings were investigated. The elevated temperature erosion studies on IN30AL coatings both as-sprayed and post-processed were investigated at 900ºC temperature at two impact angles 30º and 90º using standard high temperature erosion test rig. Phase composition, interface of substrate/coating, and morphologies of eroded coatings were examined using X-ray diffraction, X-ray maps, scanning electron microscope, & energy dispersive spectrometer techniques. Compared with the as-sprayed IN30AL coatings, the heat-treated coatings have refined microstructure, better mechanical properties which improve the elevated temperature erosion resistance of IN30ALcoatings.

A copper–germanium alloy (Cu–Ge alloy) was examined as a phase change material, at temperatures exceeding 600°C, for latent heat storage in solar thermal applications. First, the thermo-physical properties of the Cu–Ge alloy were examined using differential scanning calorimetry, thermomechanical analysis, and laser flash analysis. Second, to evaluate the thermal response and reliability of the Cu–Ge alloy, the cyclic properties of thermal charge/discharge were examined under various thermal conditions. The alloys obtained after the tests were examined for their chemical compatibility with the stainless steel container using an electron probe micro analyzer. The elemental distribution of each Cu–Ge alloy was evaluated using cyclic performance tests. Finally, the chemical compatibility of the Cu–Ge alloy was evaluated using a high-temperature test with candidate materials of a phase change material container vessel [stainless steel (SUS310S), Inconel625, silicon carbide (SiC), and alumina (Al2O3)]. The Cu–Ge alloy exhibited significant potential as a latent heat storage material in next-generation solar thermal power plants because it demonstrates various advantages, including a superior storage capacity at a temperature of 644°C, temperature coherence to the phase diagram, a quick thermal response, satisfactory cyclic behavior of charge/discharge modes, a thermodynamically stable metallographic structure, and non-reactivity with container ceramic materials (SiC and Al2O3).

Ces travaux de thèses ont pour objectif de présenter les résultats obtenus sur l'assemblage de deux couples de matériaux métal - céramiques par thermocompression : Inconel®625 / Alumine et TZM / Carbure de silicium. Elle se place dans la continuité des résultats obtenus sur des assemblages similaires, au sein du laboratoire IRCER, en étudiant la faisabilité de liaisons direct et de liaison après préoxydation de la partie métallique. Une partie est dédiée à la compréhension du mécanisme d’oxydation de l’inconel®625 en utilisant une thermobalance à insertion à chaud. A l’aide des cinétiques obtenues, le mécanisme d’oxydation est alors proposé et les conditions de préoxydation pour la partie d’assemblage suivante ont pu être déterminées. Ensuite au cours de ce manuscrit sont rapportés les procédés utilisés et les résultats obtenus après variations de paramètres tels que la température ou le temps de palier de traitement thermique sur les assemblages des deux couples. L'absence de formation d'une interphase pour le couple Inconel®625 / Alumine et la formation d'une interphase complexe pour le couple TZM / Carbure de silicium permette de proposer deux études différentes de liaison céramique- métal. Une partie est également consacrée à la caractérisation de la liaison obtenue, dans chaque cas, afin de déterminer sa tenue et expliquer ses propriétés à l'aide de la microscopie électronique à balayage mais aussi une simulation numérique pour le couple Inconel®625 / Alumine et des tests de tractions pour le couple TZM / Carbure de silicium
This work has for objective to present the results obtained for the ceramic-metal bonding by hot-pressing in two cases: Inconel®625 / Alumina and TZM / Silicon carbide. All the thesis take place according to the last results obtained for similar bonding, in the laboratory IRCER, by studying the feasibility of direct bonding and bonding after pre-oxidising the metal part. A part of this study is then dedicated to the oxidation behaviour of inconel®625 under CO2 using a thermobalance with a sample hot introduction. Using the oxidation kinetics obtained, the reaction mechanism is proposed and the conditions for the metal pre-oxidation determined.Then during the manuscript are presented the processes and the results obtained after variations of parameters such as temperature and the heat treatment time for the two couples of materials. The absence of inter-phase formation in the couple Inconel®625 / Alumina and the formation of a complex inter-phase in the couple TZM / Silicon carbide allow us to propose two studies with different metal-ceramic bonding.A last part is dedicated to the characterization and the understanding of the bonding obtained in each case. To explain the properties of the samples obtained we used scaning electron microscopy but also numerical simulation for the first couple Inconel®625 / Alumina and tensile test for the second couple TZM / Silicon carbide