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The Fundamentals of Hot Corrosion and High-Temperature Oxidation
Published in Navid Hosseinabadi, Hossein Ali Dehghanian, Suspension Plasma Spray Coating of Advanced Ceramics, 2022
Navid Hosseinabadi, Hossein Ali Dehghanian
The underlayment provides the necessary oxidation resistance for the metal substrate. This metal overlay is usually either an intrusive aluminide or an overlay coating with the general composition MCrAlY (Co and Ni = M). In modern coating systems, the substrate is generally one of the MCrAlY group coatings. This coating, at high temperatures, forms a thermally grown oxide (TGO) layer at the joint of the metal, and the ceramic layer protects the surface of the superalloy from oxidation. The top cover provides thermal insulation conditions. This ceramic layer has low thermal conductivity and is usually made of zirconia, ZrO2. Stabilized zirconia is used to prevent fuzzy transformation of zirconia and to eliminate its volumetric changes. Usually, yttrium-stable zirconia coatings with YSZ by weight percentage of Y2O3, the rest of ZrO2, are mostly used as thermal barrier coatings.
Possibilities and Limits of Temperature Control in EB-PVD Equipment Used for the Deposition of Zirconia Thermal Barrier Coatings
Published in J. Nicholls, D. Rickerby, High Temperature Surface Engineering, 2020
E. Lugscheider, C. Barimani, G. Doepper
The use of ceramic thermal barrier coatings based on partially stabilised zirconia is of great interest to the gas turbine industry. With the deposition of such coatings on turbine blades the thermal stresses can be significantly reduced. Especially EB-PVD coatings which show an outstanding strain tolerance, and therefore, a very good thermal cycling behaviour due to their columnar structure, which can be seen in Fig. 1.1 To realise such a columnar microstructure the substrate temperature plays an important role with EB-PVD deposition. Because the ionisation of vapour particles is less than 1 % without additional ionisation equipment, energy can only be adopted into the deposits by heating the substrates.2 This can be done in different ways, as there are indirect heating methods, e.g. commonly used radiant heaters, or direct heating methods such as the electron bombardment of substrates using a second electron beam (EB)-gun The last method was used in the present investigation.
Nanoparticle Synthesis by Plasma Processing
Published in C. Anandharamakrishnan, S. Parthasarathi, Food Nanotechnology, 2019
Das Trishitman, C. Anandharamakrishnan
Thermal barrier coatings are used in order to shield the component from the high temperatures, which allows the system to run at a higher temperature and thus makes the use of component more efficient. In applications, this technology focuses on turbines, where it reduces the high mechanical stress and environmental factors resulting from heat and extends the component life (Evans et al., 2001a). The thermal barrier coating is directly applied to bond coating with an intermetallic bond coat to protect the load-bearing component of the metal superalloy (Padture et al., 2001). During the thermal cycling, thermally grown oxides grow in between the coating and metal superalloy and protect the load-bearing component from creep or fatigue (Evans et al., 2001b). Although this process is less expensive compared to its application, it gives better thermal resistivity and high strain tolerance.
Thermal efficiency enhancement using a ceramic coating on the cylinder liner and the piston head of the IC engine
Published in International Journal of Ambient Energy, 2021
P. Anand, D. Rajesh, M. Shunmugasundaram, I. Saranraj
In the automobile sector, the main objective is to improve the performance by reducing the fuel consumption of an engine and increase the power. The diesel engine has the highest thermal efficiency of any standard combustion engine due to its very high compression ratio (Kamo and Bryzik 1978). Diesel engines are more efficient than gasoline (petrol) engines of the same power rating resulting in lower fuel consumption. The increased fuel economy of the diesel engine over the petrol engine produces less carbon dioxide per unit distance. The design and development of a high power with low heat rejection, direct injection automotive diesel engines requires a thorough knowledge of in-cylinder combustion and heat transfer characteristic (Kamo and Bryzik 1979). These information and analysis will be helpful in designing an energy-efficient engine, by coating with ceramics over the cylinder liner and piston head. Thermal barrier coatings are highly advanced material systems applied to metallic surfaces, such as gas turbine aero-engine and diesel engine parts, operating at elevated temperatures (Kamo and Bryzik 1981). These coatings serve to insulate metallic components from large and prolonged heat loads by utilising thermally insulating materials which can sustain an appreciable temperature difference between the load bearing alloys and the coating surface (Bryzik and Kamo 1983). In doing so, these coatings can allow for higher operating temperatures while limiting the thermal exposure of structural components, extending part life by reducing oxidation and thermal fatigue.
Thermal barrier coated diesel engine running on biodiesel: a review
Published in International Journal of Sustainable Engineering, 2018
Plasma spraying method is the most popular technique to deposit thermal barrier coating in engine components due to its higher porosity (Karaoglanli et al. 2011; Salman et al. 2006). This method is suitable to apply in a surface which melts at a very high temperature. Prior to coating, the substrate surface was sand blasted to produce a surface roughness (Ra) of 4–5 μm. The sand blasted substrates were ultrasonically cleaned using anhydrous ethylene alcohol and dried in cold air. A plasma spray system consists of a power supply, gas source, gun and powder feeding mechanism. An arc is formed between an electrode and spray nozzle, which acts as a secondary electrode. A pressurised inert gas is passed between the electrodes where it is heated to a very high temperature (>16,000 °C) to form plasma jet (Bhatia 1999). The material to be deposited (feedstock) can be a powder, liquid, suspension or wire and is introduced into the plasma jet by emanating from a plasma torch. For a deposition rate of 1–5 kg/h, particle velocity reaches 200–300 m/s, porosity is reduced to 5–10% and oxide content to 1–3%. In the jet, the material is melted and propelled towards a substrate. Therefore, the molten droplets flatten, rapidly solidify and form a deposit. In this process, thickness of material is deposited on engine component in the range of 50–500 μm.
Impact of partially stabilised zirconia on a single-cylinder diesel engine’s performance, using orange oil methyl ester biodiesel
Published in International Journal of Ambient Energy, 2018
Orange oil methyl ester was used as an alternative fuel in direct injection diesel engines.Partially stabilised zirconia was used as a thermal barrier coating material.Performance and emission characteristics of B1 and diesel were observed and compared.Improved BTE and declined BSFC were observed with B1.Both diesel and B1 showed reduced emission in coated engines.