Thermal shock properties and failure mechanism of plasma sprayed Al2O3/TiO2 nanocomposite coatings

2005 ◽  
Vol 31 (6) ◽  
pp. 817-824 ◽  
Author(s):  
Chang-sheng Zhai ◽  
Jun Wang ◽  
Fei Li ◽  
Jing-chao Tao ◽  
Yi Yang ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Failure Mechanism ◽  
Nanocomposite Coatings ◽  
Plasma Sprayed

Fabrication and Ablation Behavior of Plasma Sprayed ZrC-W Composite Coatings

2014 ◽  
Vol 602-603 ◽  
pp. 552-555
Author(s):  
Dan Lu ◽  
Ya Ran Niu ◽  
Xue Lian Ge ◽  
Xue Bing Zheng ◽  
Guang Chen
Keyword(s):  
Thermal Conductivity ◽  
Thermal Shock ◽  
Plasma Spray ◽  
Composite Coatings ◽  
Lamellar Microstructure ◽  
Atmospheric Plasma Spray ◽  
Atmospheric Plasma ◽  
Plasma Flame ◽  
Plasma Sprayed ◽  
Zrc Coating

In this work, atmospheric plasma spray (APS) technology was applied to fabricate ZrC-W composite coatings. The microstructure of the composite coatings was characterized. The influence of W content on the ablation-resistant and thermal shock properties of ZrC-W composite coatings was evaluated using a plasma flame. The results show that the ZrC-W composite coatings had typically lamellar microstructure, which was mainly made up of cubic ZrC, cubic W and a small amount of tetragonal ZrO2. The ZrC-W coatings had improved ablation resistant and thermal shock properties compared with those of the pure ZrC coating. It was supposed that the improved density, thermal conductivity and toughness of the composite coatings contributed to this phenomenon.

Vacuum Plasma Sprayed ZrO2-Based Thermal Barrier Coatings for Aerospace Applications

1998 ◽  
Author(s):  
T. Brzezinski ◽  
A. Cavasin ◽  
S. Grenier ◽  
E. Kharlanova ◽  
G. Kim ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Thermal Barrier Coatings ◽  
Temperature Drop ◽  
Single Step ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Vacuum Plasma Spray ◽  
Barrier Coatings ◽  
Vacuum Plasma ◽  
Plasma Sprayed

Abstract Zirconia-based thermal barrier coatings (TBCs), produced using Vacuum Plasma Spray (VPS) technology, were recently subjected to burner rig testing. The VPS TBC performance was compared to TBCs deposited using conventional Atmospheric Plasma Sprayed (APS) and Electron Beam Physical Vapor Deposition (EB-PVD) techniques. All of the coatings consisted of an MCrAlY bond coat and a partially stabilized ZrO2-8%Y2O3 (PSZ) top coat. The TBC coated pins (6.35 mm in diameter) were tested using gas temperatures ranging from 110CC to 1500°C. The pins were tested to failure under severe conditions (1500°C gas temperature, with no internal cooling). The initial testing indicated that under typical operating gas temperatures (1400°C), the VPS TBC performance was comparable, if not superior, to conventional TBCs. Following the encouraging results, thick composite TBCs, produced in a single-step operation, were investigated. Preliminary work on ZrO2-8% Y2O3/Ca2SiO4 composite TBCs with interlayer grading included thermal shock testing and temperature drop measurements across the TBC. The composite TBC thicknesses ranged from 850µm to 1.8 mm. Initial results indicate that thick adherent composite TBCs, with high resistance to severe thermal shock, can be produced in a single step using the VPS process.

Plasma Sprayed WC-12%Co-Coatings for TBC Applications on Diesel Engine Piston

2019 ◽  
Vol 7 (1) ◽  
pp. 37-54 ◽  
Author(s):  
Debasish Das ◽  
Rajeev Verma ◽  
Vipul Pathak
Keyword(s):  
Diesel Engine ◽  
Thermal Shock ◽  
Structural Changes ◽  
Strain Analysis ◽  
Sem Analysis ◽  
Thermal Barrier ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
Thermal Shock Behavior ◽  
Plasma Sprayed

In the present study, plasma sprayed WC-12%Co coatings with 100µm NiCrAlY bond coat on a substrate of A336 cast aluminum alloy have been investigated for a thermal barrier coating (TBC) application. The coatings deposited with varying topcoat thickness up to 500µm were deposited on the piston top surface of an Indian hatchback diesel car to act as a thermal barrier and enhance the thermal efficiency of the engine. Although all the specimens with distinct coating overlays survived 350 thermal cycles, the one with 200µm thickness exhibited the best thermal shock behavior as they exuded the most cycles to surface cracks initiation. Moreover, SEM analysis also suggested 200 µm thick coating to be optimal for thermal shock behavior in diesel engine components. The coating phase analysis by XRD and the lattice strain analysis performed by a Williamson-Hall (W-H) analysis did not reveal any structural changes after the thermal shock experiment.

scholarly journals LC/8YSZ TBCs Thermal Cycling Life and Failure Mechanism under Extreme Temperature Gradients

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1051
Author(s):  
Kun Liu ◽  
Xi Chen ◽  
Kangping Du ◽  
Yu Wang ◽  
Jinguang Du ◽  
...  
Keyword(s):  
High Temperature ◽  
Surface Temperature ◽  
Thermal Cycling ◽  
Thermal Shock ◽  
Failure Mechanism ◽  
Extreme Temperature ◽  
Temperature Gradients ◽  
Accelerated Life Test ◽  
Ceramic Layer ◽  
Cycling Life

The purpose of this paper is to study the thermal shock resistance and failure mechanism of La2Ce2O7/8YSZ double-ceramic-layer thermal barrier coatings (LC/8YSZ DCL TBCs) under extreme temperature gradients. At high surface temperatures, thermal shock and infrared temperature measuring modules were used to determine the thermal cycling life and insulation temperature of LC/8YSZ DCL TBCs under extreme temperature gradients by an oxygen–acetylene gas flame testing machine. A viscoelastic model was used to obtain the stress and strain law of solid phase sintering of a coating system using the finite element method. Results and Conclusion: (1) Thermal cycling life was affected by the surface temperature of LC/8YSZ DCL TBCs and decreased sharply with the increase of surface temperature. (2) The LC ceramic surface of the failure coating was sintered, and the higher the temperature, the faster the sintering process. (3) Accelerated life test results showed that high temperature thermal cycling life is not only related to thermal fatigue of ceramic layer, but is also related to the sintering degree of the coating. (4) Although the high temperature thermal stress had great influence on the coating, great sintering stress was produced with sintering of the LC ceramic layer, which is the main cause of LC/8YSZ DCL TBC failure. The above results indicate that for new TBC ceramic materials, especially those for engines above class F, their sinterability should be fully considered. Sintering affects the thermal shock properties at high temperature. Our research results can provide reference for material selection and high temperature performance research.

Thermal Shock Resistance of Plasma Sprayed Multi-Layered Functionally Graded Cr3C2-NiCr Coatings

2016 ◽  
Vol 852 ◽  
pp. 1000-1005 ◽  
Author(s):  
Dong Xing Fu ◽  
Jing Na Liu ◽  
Er Bao Liu ◽  
Zhao Bin Cai ◽  
Xiu Fang Cui ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Functionally Graded ◽  
X Ray Diffraction ◽  
Coating Materials ◽  
Heating And Cooling ◽  
Structure Of Coatings ◽  
Functionally Graded Coatings ◽  
Shock Resistance ◽  
Plasma Sprayed

The interface properties of multi-layered functionally graded Cr3C2-NiCr coatings deposited by plasma spraying technique were experimentally studied in this paper. The microstructure and phase structure of coatings were studied with scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The thermal shock resistance was investigated by cyclic heating and cooling tests using an electro-calefaction furnace. The crack appearances of the coatings were observed carefully. Results show that the plasma sprayed multi-layered functionally graded coatings are compact and the adhesion between the layers and the substrate is good. The coatings have better macro-hardness than the substrate, and the 6-layers coating has the highest macro-hardness and the best wear resistance. Besides, the micro-hardness of coatings increases with increasing content of Cr2C3 in coating materials. Results of cyclic thermal shock show that the main failure styles of the coatings are crack and desquamation and the thermal shock resistance of the coatings is improved obviously by increasing the number of coating layers.

Plasma Sprayed 4-Phase Ceramic Abradable Seal Coatings and their Thermal Shock Resistance on Nickel-Based Superalloy

2014 ◽  
Vol 1058 ◽  
pp. 274-278
Author(s):  
Jun Guo Gao ◽  
Feng Lu ◽  
Meng Qiu Guo
Keyword(s):  
Thermal Shock ◽  
Bond Coat ◽  
Thermal Stresses ◽  
Thermal Shock Test ◽  
Porous Structures ◽  
Good Adhesion ◽  
Nickel Based Superalloy ◽  
Abradable Coating ◽  
Shock Resistance ◽  
Plasma Sprayed

Novel 4-phase ceramic abradable seal coatings have been prepared by plasma spray. The as-prepared coatings were characterized by SEM, EDS and XRD. The results showed that the 4-phase ceramic abradable coating exhibited porous structures and had good adhesion with the bond coat. The ZrO2 and Al2O3 in the coating existed in the form of tetragonal-ZrO2 and α-Al2O3, respectively. The result of thermal shock test revealed that compared with the 3-phase abradable coating, the thermal shock life of the 4-phase abradable coating had increased tenfold to 1900~2000 cycles from 100~200 cycles. The reason is owing to the reduction of oxygen partial pressure and thermal stresses at the top/bond coat interface due to the addition of the fourth nanoAl2O3 phase.

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