Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 16 of 16 for “"carburization"”.
-
Computer simulation of carburization corrosion of nickel-base superalloys
… the predictions of model were compared to carburization profiles obtained experimentally in H₂-CH₄ environment tests. Results are presented for the formation of Cr, Mo, Ti, W, and Nb carbides in Ni-based superalloys. The predicted corrosion profiles are in qualitative agreement with …
-
Modeling of high fluence Ti ion implantation and vacuum carburization in steel
Concentration-versus-depth profiles have been calculated for Ti and C in Ti-implanted 52100 steel. A computer formalism was developed to account for diffusion and mixing processes, as well as sputtering and lattice dilation. A Gaussian distribution of Ti was assumed to be incorporated at each time …
-
Investigation of carburization extent from the inner diameter (ID) of ethylene furnace tubes using non-destructive examination (NDE) applied on the outer diameter (OD)
… of measuring the depth and location of carburization and metal dusting on the inside of ethylene pyrolysis tubes using nondestructive tools applied to the outer surface. A carburization test was conducted in a specially designed and manufactured HK-40 alloy tube. Ethylene pyrolysis is …
-
Reduction and softening/melting behaviour of olivine pellet in the experimental blast furnace
… in the cohesive zone of blast furnace. The carburization characteristics of reduced iron were also investigated by examining olivine pellet and coke samples excavated and probed from an experimental blast furnace as well as the experimental investigations of pure hematite and heat treated …
-
Comparison of oil and intensive quenching via coupled thermal, transformation, and mechanical modeling
… bar. These simulations included three carburization levels: non-carburized, carburized to 0.8 wt pct C and 1.0 wt pct C at the surface utilizing a plain carbon steel (1020) and three alloy steels (4120, 4320, and 8620) representing a range of hardenabilities. Both industrially standard …
-
Surface degradation and creep of Inconel 617 and Haynes 230 at high temperatures
… the materials can undergo oxidation, carburization and decarburization, which can be detrimental to the mechanical behavior of the materials. In addition, the most critical metallic component of the HTGR is the heat exchanger. The materials serve in the temperature range of 760-950oC …
-
Carbeto de molibdênio promovido por níquel como catalisador na reação de reforma seca do metano
… X-ray diffraction (XRD), temperature-programmed carburization (TPC), scanning and transmission electron microscopy (SEM and TEM), N2 physisorption, CO chemisorption, temperature-programmed surface reaction (TPSR) and Raman spectroscopy. The catalysts evaluations showed that the nanostructured …
-
Application of Molybdenum Carbide Catalysts for the CO2-assisted Oxidative Dehydrogenation of Ethane
… exposed to a temperature programmed treatment (carburization) in the presence of a carbonaceous and reductive gas mixture. The carbide formation, in terms of crystallite structure, surface composition as well as potential fouling mechanisms is highly dependent on the heating rate, gas mixture, …
-
Structure-activity relationships for the water-gas shift reaction over supported metal catalysts
… on the MO<sub>2</sub>C support after a 600°C carburization pretreatment, making MO<sub>2</sub>C an ideal candidate for the synthesis of thermally robust supported metal catalysts. The difficulties in characterization of Pt/MO<sub>2</sub>C by electron microscopy were overcome by using …
-
Catalytic upgrading of biomass through the hydrodeoxygenation (HDO) of bio-oil derived model compounds
… reduced MoO₃ surface through its partial carburization to oxycarbide phase (MoOxCyHz) at temperatures < 623 K. Thereafter, TiO₂ and ZrO₂ supports prevent the reduction of dispersed oligomeric MoOx species to catalytically inactive species, enhancing their stability. In addition, the …
-
Analysis of the mechanical response of LMFBR fuel clads subjected to in-service property variations
… impurities by diffusion, compound formations and carburization/decarburization behavior have been observed to occur. Mechanical property measurements such as tensile and yield strengths made under these conditions indicate that thermal and thermochemical influences can result in variations in the …
-
Investigation of the promotional effect of Cu and Ag on iron-based Fischer-Tropsch catalysts using ferrites as model catalysts
… removal from the catalytic surface or in the carburization of particularly superparamagnetic Fe3O4. It is further shown that the olefin selectivity in the Fischer-Tropsch synthesis over the catalyst AgFeO2 (ex) is higher than that obtained over the catalyst CuFe2O4 (ex) and CuFeO2 (ex), which …
-
Perovskites as New Support Materials for the Iron Based Fischer-Tropsch Synthesis
… C/H ratio on the catalyst surface and faster carburization rates, longer chain products and higher olefin content [5,7,8]. The addition of promoters is beneficial up to a certain amount, above which it becomes detrimental to the overall activity of the catalyst due to coverage of active sites …
-
Adding ammonia during Fischer-Tropsch Synthesis: Pathways to the formation of N-containing compounds
… after 48 hours time on stream (TOS)). A slower carburization period was however observed when comparing the CO conversion during the first 24 hours TOS, and further supported by the slow increase in CO₂ selectivity during the same period. The use of two-dimensional gas chromatography (GC × …
-
Metallic cobalt derived from cobalt nitrides for Fischer-Tropsch Synthesis
… hcp Co nanoparticles is through a reduction carburization-reduction (RCR) route or via the reduction of hexagonal cobalt oxide. The former route produces a catalyst that is predominantly hcp Co, however not all of the carbon is able to be removed, especially at lower second reduction end …
-
High Temperature Corrosion Studies of Metallic Materials in High Temperature Gas-Cooled Nuclear Reactor Helium Environment
Made available in DSpace on 2017-07-06T18:55:04Z (GMT). No. of bitstreams: 3 Lee_Daniel_K_MS.pdf: 75457165 bytes, checksum: 1c352f8a0eaf27a3c60286c777a82659 (MD5) Lee_Daniel_K_MS_ABS.pdf: 628459 bytes, checksum: 9adc2363b16d312ea8d65075fd1b4b1f (MD5) license.txt: 4813 bytes, checksum: …