Decomposition process of Sm2Zr2O7+8YSZ composite TBC systems in conditions of hot corrosion

2019 ◽  
Vol 1 (10) ◽  
pp. 12-14 ◽  
Author(s):  
GRZEGORZ MOSKAL
Keyword(s):  
Hot Corrosion ◽  
Decomposition Process ◽  
Tbc Systems

scholarly journals Cyclic Hot Corrosion Failure Behaviors of EB-PVD TBC Systems in the Presence of Sulfate and Vanadate Molten Salts

Coatings ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 166 ◽  
Author(s):  
Yasin Ozgurluk ◽  
Kadir Doleker ◽  
Dervis Ozkan ◽  
Hayrettin Ahlatci ◽  
Abdullah Karaoglanli
Keyword(s):  
Hot Corrosion ◽  
Physical Vapor Deposition ◽  
Operating Conditions ◽  
Corrosion Failure ◽  
Bond Coats ◽  
Barrier Coating ◽  
Metallic Bond ◽  
Cold Gas Dynamic Spray ◽  
Gas Dynamic Spray ◽  
Tbc Systems

The cold gas dynamic spray (CGDS) method has been considered a promising technology to produce a metallic bond coat for thermal barrier coating (TBC) systems. In this study, CoNiCrAlY bond coats produced by CGDS method were coated with yttria-stabilized zirconia (YSZ) by electron beam physical vapor deposition (EB-PVD). TBCs were subjected to 50 wt % V2O5 and 50 wt % Na2SO4 molten hot corrosion salt combinations at 1000 °C. In the case of YSZ top coat on TBCs, the reaction between Na2SO4, V2O5, and Y2O3 salts generates YVO4 crystals, and these structures cause the transformation of tetragonal ZrO2 to monoclinic ZrO2. This situation occurs under operating conditions that lead to TBC failure. Hot corrosion behavior and the related failure mechanisms of TBC systems were investigated and discussed using scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) analysis, and X-ray diffractometer (XRD).

Environmental Effect of Hot Corrosion on Creep and Fatigue Failure of Thermal Barrier Coating Systems

2006 ◽  
Vol 522-523 ◽  
pp. 353-360
Author(s):  
Satoru Takahashi ◽  
Masayuki Yoshiba ◽  
Wataru Kakuta ◽  
Sayuri Matsuoka ◽  
Yoshio Harada
Keyword(s):  
Thermal Barrier Coating ◽  
Hot Corrosion ◽  
Nucleation Site ◽  
Major Constituent ◽  
Failure Behavior ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Failure Life ◽  
Corrosive Environments ◽  
Tbc Systems

In order to clarify the failure behavior of plasma sprayed thermal barrier coating (TBC) systems under the complicated modes of thermal-mechanical-chemical loadings, the stress rupture property evaluation and failure analysis were conducted for Y2O3-ZrO2 (YSZ) and CaO-SiO2-ZrO2 (C2S-CZ) TBC systems in air and two kinds of high-temperature corrosive environments. Static creep loading was found to bring about the typical creep failure for TBC systems even in the aggressive environment so called hot corrosion almost in similar manner to the case in air. On the contrary, it was revealed that the dynamic fatigue loading tends to cause a significant failure life reduction of TBC systems both in air and in corrosive environments. For YSZ TBC system, the penetration crack preexisting through the top-coat layer tends to provide a nucleation site for the fatigue crack even in air, and more significantly a short circuit path for the corrosive species in hot corrosive environment. For C2S-CZ system, on the contrary, the top-coat / bond-coat interface tends to provide easily the nucleation site for a main crack to propagate thereafter toward both the alloy interior and outer surface. Under lower stress level at 950°C, however, the oxide-induced crack closure together with crack tip blunting attributed mainly to the high reactivity of Ca compounds as a major constituent of the TC is effective to suppress substantially the crack propagation, so as to cause the prolonged failure life as compared to YSZ system even in aggressive gaseous environment.

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').

Decomposition Process of Benzene in a Low Pressure DC Glow Discharge

2010 ◽  
Vol 130 (11) ◽  
pp. 1004-1008
Author(s):  
Shinobu Hayashi ◽  
Kohki Satoh ◽  
Hidenori Itoh
Keyword(s):  
Glow Discharge ◽  
Low Pressure ◽  
Decomposition Process ◽  
Dc Glow Discharge

Influence of Carbon on the Hot Corrosion Behaviour of Fe-Base Alloys

1989 ◽  
Vol 30 (9) ◽  
pp. 707-716 ◽  
Author(s):  
A. U. Malik ◽  
M. Ishaq ◽  
Sharif Ahmad ◽  
Sultan Ahmad
Keyword(s):  
Hot Corrosion ◽  
Corrosion Behaviour

Colonization of decomposing Sphagnum moss litter by mycorrhizal roots in two types of peatland ecosystems

2014 ◽  
Vol 10 ◽  
pp. 113-121
Author(s):  
Mateusz Wilk ◽  
Julia Pawłowska ◽  
Marta Wrzosek ◽  
Michał Gorczak ◽  
Małgorzata Suska-Malawska
Keyword(s):  
Molecular Identification ◽  
Decomposition Process ◽  
Sphagnum Moss ◽  
Forest Communities ◽  
Litter Bags ◽  
Poor Fen ◽  
The Poor ◽  
Ectomycorrhizal Roots ◽  
Mycorrhizal Roots ◽  
Ectomycorrhizal Morphotypes

During a 35-month study on the decomposition of Sphagnum moss litter in poor fen and pine bog forest, an intensive colonization of litter-bags by mycorrhizal roots was observed during the decomposition process. Content of mycorrhizal roots in litter-bags, expressed as % mass of roots, was generally increasing during the decomposition in pine bog forest, and fluctuating during decomposition on poor fen, although in both cases the results were statistically insignificant. Two morphotypes of ericoid roots and two morphotypes of ectomycorrhizal roots were recorded from litter-bags on poor fen during the decomposition experiment, while in pine bog forest one morphotype of ericoid and nine morphotypes of ectomycorrhizal roots were recorded. Molecular identification of mycorrhizal roots succeeded only in the case of one ericoid and six putatively ectomycorrhizal morphotypes. Most morphotypes were recorded only once during the whole 35-month decomposition period, and only one ericoid and one ectomycorrhizal morphotypes were shared between the poor fen and pine bog forest communities.

ROLLED ALLOYS HR-120

Alloy Digest ◽  
2000 ◽  
Vol 49 (10) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Thermal Processing ◽  
Hot Corrosion ◽  
Heat Treating ◽  
Temperature Performance

Abstract HR-120 alloy is an alloy designed for thermal processing. It possesses excellent strength, oxidizing hot corrosion resistance, good carburization resistance, and oxidation resistance through 1093 deg C (2000 deg F). This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Ni-561. Producer or source: Rolled Alloys.

Effect of laser shock peening on microstructure and hot corrosion of TC11 alloy

2018 ◽  
Vol 335 ◽  
pp. 32-40 ◽  
Author(s):  
Zhaopeng Tong ◽  
Xudong Ren ◽  
Yunpeng Ren ◽  
Fengze Dai ◽  
Yunxia Ye ◽  
...  
Keyword(s):  
Hot Corrosion ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Shock Peening
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