scholarly journals Optimizing Coating Thickness of Electrophoretic Deposition Overlay on Plasma Sprayed YSZ Coating Using Taguchi Method

2022 ◽  
Vol 961 (1) ◽  
pp. 012060
Author(s):  
Ruqayah A. Abbas ◽  
Sami A. Ajeel ◽  
Maryam A. Ali Bash ◽  
Mohammed J. Kadhim
Keyword(s):  
Taguchi Method ◽  
Electrophoretic Deposition ◽  
Coating Thickness ◽  
Deposition Time ◽  
Signal To Noise Ratio ◽  
Protective Layer ◽  
Barrier Coating ◽  
Ysz Coating ◽  
Plasma Sprayed ◽  
Dc Current

Abstract In this study, nano sized yttria stabilized zirconia (YSZ) suspension in organic solution was deposited by electrophoretic deposition (EPD) method as a protective layer on substrate that was previously plasma sprayed thermal barrier coating (TBCs). In order to improve the performance of TBC from degradation by melt ingression of fuel impurities. Design of experiments (DOE) by Taguchi method was used to optimize the controlled variables of EPD process. A crack free YSZ overlay coating was carried out at different variables; applied voltage (20, 40, 60) V, deposition time (3, 5, 7) min and suspension concentration (5, 10, 15) g/l using DC current. Morphological appearance and cross section of the investigated coating specimen were done using optical and field emission scanning electron microscope. Optimizing process and analysis of variances (ANOVA) were performed by “Minitab 18” software. The results indicate that best condition of coating thickness can be obtained at 40V, 5min and 10g/l when applying signal-to-noise ratio “Larger is better”.

scholarly journals The Role of Nanostructured Al2O3Layer in Reduction of Hot Corrosion Products in Normal YSZ Layer

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Mohammadreza Daroonparvar ◽  
Muhamad Azizi Mat Yajid ◽  
M. Y. Noordin ◽  
Mohammad Sakhawat Hussain
Keyword(s):  
Outer Layer ◽  
Hot Corrosion ◽  
Molten Salts ◽  
Corrosion Products ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coating ◽  
Ysz Coating ◽  
Plasma Sprayed

YVO4crystals and monoclinic ZrO2are known as hot corrosion products that can considerably reduce the lifetime of thermal barrier coatings during service. The hot corrosion resistance of two types of air plasma sprayed thermal barrier coating systems was investigated: an Inconel 738/NiCrAlY/YSZ (yttria-stabilized zirconia) and an Inconel 738/NiCrAlY/YSZ/nano-Al2O3as an outer layer. Hot corrosion test was accomplished on the outer surface of coatings in molten salts (45% Na2SO4+ 55% V2O5) at 1000°C for 52 hour. It was found that nanostructured alumina as outer layer of YSZ/nano-Al2O3coating had significantly reduced the infiltration of molten salts into the YSZ layer and resulted in lower reaction of fused corrosive salts with YSZ, as the hot corrosion products had been substantially decreased in YSZ/nano-Al2O3coating in comparison with normal YSZ coating after hot corrosion process.

Comparison of Hot Corrosion Behaviors of Plasma-Sprayed Segmented Structure and Conventional YSZ Thermal Barrier Coatings under a Fused Na2SO4-V2O5 Salt Film

2014 ◽  
Vol 1061-1062 ◽  
pp. 234-239
Author(s):  
Yi Wang ◽  
Yi Chen Meng ◽  
Hong Li Suo ◽  
Pan Wang
Keyword(s):  
Thermal Barrier Coating ◽  
Chemical Interaction ◽  
Substrate Surface ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Abnormal Growth ◽  
Salt Film ◽  
Barrier Coating ◽  
Ysz Coating ◽  
Plasma Sprayed

A modified YSZ thermal barrier coating (TBC) was prepared by simultaneously depositing two components, NiCrAlY and YSZ, on nicked-based superalloy DZ125 via atmospheric plasma spraying. In this study, the sodium salt was deposited on substrate surface. After being heated at 950°C for 50min, the specimens were cooled to ambient temperature within 10 min. The specimens were recoated after each 10 cycles. Subsequently, the corrosion products were analyzed via X-Ray diffraction and SEM. The results indicated that deterioration of YSZ coating mainly resulted from generation of chemical interaction. Conversely, abnormal growth of TGO and enrichment of molten salt around segmentation crack were not observed in the modified YSZ thermal barrier coating. Moreover, the modified YSZ-TBC exhibited higher thermal resistance than traditional YSZ-TBC in the thermal cycling testing.

scholarly journals Improved Thermally Grown Oxide Scale in Air Plasma Sprayed NiCrAlY/Nano-YSZ Coatings

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Mohammadreza Daroonparvar ◽  
Muhamad Azizi Mat Yajid ◽  
Noordin Mohd Yusof ◽  
Mohammad Sakhawat Hussain
Keyword(s):  
Oxide Scale ◽  
Thermal Barrier Coating ◽  
Thermally Grown Oxide ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coating ◽  
Ysz Coating ◽  
Thermally Grown Oxide Scale ◽  
Plasma Sprayed ◽  
Thermally Grown

Oxidation has been considered as one of the principal disruptive factors in thermal barrier coating systems during service. So, oxidation behavior of thermal barrier coating (TBC) systems with nanostructured and microstructured YSZ coatings was investigated at1000∘Cfor 24 h, 48 h, and 120 h. Air plasma sprayed nano-YSZ coating exhibited a trimodal structure. Microstructural characterization also demonstrated an improved thermally grown oxide scale containing lower spinels in nano-TBC system after 120 h of oxidation. This phenomenon is mainly related to the unique structure of the nano-YSZ coating, which acted as a strong barrier for oxygen diffusion into the TBC system at elevated temperatures. Nearly continues but thinner Al2O3layer formation at the NiCrAlY/nano-YSZ interface was seen, due to lower oxygen infiltration into the system. Under this condition, spinels formation and growth on the Al2O3oxide scale were diminished in nano-TBC system compared to normal TBC system.

HOT CORROSION OF CERIA-YTTRIA STABILIZED ZIRCONIA PLASMA SPRAYED THERMAL BARRIER COATING BY EUTECTIC VANDIUM PENTAOXIDE-SODIUM SULFATE

2018 ◽  
Vol 18 (1) ◽  
pp. 182-192 ◽  
Author(s):  
Mohammed J Kadhim ◽  
Mohammed H Hafiz ◽  
Maryam A Ali Bash
Keyword(s):  
Thermal Barrier Coating ◽  
Hot Corrosion ◽  
Monoclinic Phase ◽  
Volume Fraction ◽  
High Volume ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Plan View ◽  
Barrier Coating ◽  
Plasma Sprayed

The high temperature corrosion behavior of thermal barrier coating (TBC) systemconsisting of IN-738 LC superalloy substrate, air plasma sprayed Ni24.5Cr6Al0.4Y (wt%)bond coat and air plasma sprayed ZrO2-20 wt% ceria-3.6 wt% yttria (CYSZ) ceramic coatwere characterized. The upper surfaces of CYSZ covered with 30 mg/cm2 , mixed 45 wt%Na2SO4-55 wt% V2O5 salt were exposed at different temperatures from 800 to 1000 oC andinteraction times from 1 up to 8 h. The upper surface plan view of the coatings wereidentified for topography, roughness, chemical composition, phases and reaction productsusing scanning electron microscopy, energy dispersive spectroscopy, talysurf, and X-raydiffraction. XRD analyses of the plasma sprayed coatings after hot corrosion confirmed thephase transformation of nontransformable tetragonal (t') into monoclinic phase, presence ofYVO4 and CeVO4 products. Analysis of the hot corrosion CYSZ coating confirmed theformation of high volume fraction of YVO4, with low volume fractions of CeOV4 and CeO2.The formation of these compounds were combined with formation of monoclinic phase (m)from transformation of nontransformable tetragonal phase (t').

Ultra-Low-Power Electrophoretic Deposition of Silica Powder with Nonflammable Organic Solvent

2015 ◽  
Vol 654 ◽  
pp. 88-93
Author(s):  
Hideyuki Negishi
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Electrophoretic Deposition ◽  
Particle Concentration ◽  
Deposition Time ◽  
Ultra Low Power ◽  
Silica Powder ◽  
Inorganic Particles ◽  
Uniform Coating ◽  
Electrical Insulation Properties

Although conventional organic solvents are used in electrophoretic deposition (EPD) owing to several advantages, they are hazardous because of their inflammability or ignition properties. In contrast, hydrofluoro ether (HFE) is nonflammable, polar and possesses excellent electrical insulation properties. In this study, methoxy-nonafluorobutane (MNFB), which is one of HFE was used as the solvent for the EPD of silica powder. Because the density of MNFB is larger than water, sedimentation of inorganic particles is slow. The deposition behavior in MNFB was similar to the EPD in conventional solvents, and was controlled by tuning the applied voltage, deposition time, and particle concentration. A uniform coating was obtained. Notably, the power consumed in this process was significantly lower than that in the EPD using conventional solvents. The current density was of the order of 10 nA/cm2; therefore, the electric power consumption for EPD using MNFB was less than 0.1% of those using conventional solvents. Therefore, MNFB can be used as an effective solvent for EPD because it is nonflammable, allows the application of high voltage, and enables the deposition of particles with low power consumption.

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