نتایج جستجو برای: Diffusion layer
تعداد نتایج: 436727 فیلتر نتایج به سال:
thermal barrier coatings (tbcs) are used to provide thermal insulation to the hot section components of gas turbines in order to enhance the operating temperature and turbine efficiency. hot corrosion and thermal shocks are the main destructive factors in tbcs which comes as a result of oxygen and molten salt diffusion into the coating. in this thesis atmospheric plasma spraying was used to dep...
In this article, a two dimensional pore scale model of polymeric fuel cell, which is promising of a clean and renewable energy production, is presented here. Let reactive gases behave as an ideal gas; inhomogeneous anisotropic structure of the gas diffusion layer, is contemplated as a random generated circular porous media. Lattice Boltzmann method is applied to inquire the fluid flow and mass ...
in this study, as for the re-casting, surface alloying and re-solidification layer of this alloys at the work piece level machining with wire electro discharge machining (wedm), changes of surface micro hardness with changes of operational parameters has been studied. therefore, study shows using surface alloying phenomena with the diffusion of wire material into the machined surface and select...
in this paper, the effect of surface area of reaction layers in gas diffusion electrodes on oxygen reduction reaction was investigated. for this purpose, various amounts (0.1, 0.2, 0.3, 0.4, 0.5, 1, 1.5 and zero %wt of total loading of reaction layer) of single walled carbon nanotube (swcnt) were inserted in the reaction layer. the performance of gas diffusion electrodes for oxygen reduction re...
In this research, effects of changes in aluminizing conditions on microstructure of Pt - aluminide coating applied oil a Ni - base superalloy GTD -111, has been studied. A thin layer (i.e.68,#mm ) of Pt was electroplated onto the surface of the .samples, and then they were aluminized by pack cementation technique under various conditions of time, temperature, rate of heating and pack powder com...
- The mechanism of diffusion layer growth in plasma nitrided coatings applied on a St52 steel using an active screen is investigated. The nitriding was performed at 450,500 and 550 ◦C temperature nitriding times of 5, 10 and 15 h, in a gas mixture containing 20 vol. % H2: 80 vol. % N2 and DC-pulsed plasma nitriding unit. The surface, cross section and the thickness of diffusion of specimens ...
the cold roll bonding of al on aisi 304l stainless steel was carried out to fabricate the al/304l/al clad sheet composites. the maximum bond strength of 20 n/mm was acquired just by 38% reduction, for which the tearing of the aluminum sheet occurred during the peeling test. the microstructural evolution during subsequent postannealing heat treatment was systematically studied based on the impur...
The use of Fe-Al intermetallic compound coatings has been investigated in order to improve the tribological behaviour of carbon tool steel. The coatings were formed by a pack cementation process and subsequently diffusion annealing at 900˚C in an argon controlled atmosphere. The optimum diffusion time was selected on the basis of optimum thickness and tribological behaviour.
The microstructu...
In this study, the effect of temperature on the microstructure and reactive layer at the interface between the Ti interlayer and the base metal related to the diffusion bonding of Zr702 to A516 low alloy steel was investigated. The joining was done using the spark plasma sintering technique at temperatures of 900, 950 and 1000°C for 30 minutes. Field Emission Scanning Electron Microscope (FESEM...
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