Thermal shock behaviours of atmospheric plasma sprayed NiCrAlY/Al2O3–20%TiO2 gradient coating on Cu–Be alloy

2020 ◽  
Vol 36 (10) ◽  
pp. 1113-1120
Author(s):  
Min Li ◽  
Kun Xia Wei ◽  
Wei Wei ◽  
Qing Bo Du ◽  
Xiao Bing Zhao ◽  
...  
2014 ◽  
Vol 602-603 ◽  
pp. 552-555
Author(s):  
Dan Lu ◽  
Ya Ran Niu ◽  
Xue Lian Ge ◽  
Xue Bing Zheng ◽  
Guang Chen

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.


Author(s):  
T. Brzezinski ◽  
A. Cavasin ◽  
S. Grenier ◽  
E. Kharlanova ◽  
G. Kim ◽  
...  

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.


2012 ◽  
Vol 472-475 ◽  
pp. 246-250 ◽  
Author(s):  
Hossein Jamali ◽  
Reza Mozafarinia ◽  
Reza Shoja Razavi ◽  
Raheleh Ahmadi Pidani

ZrO2-8wt.%Y2O3 (8YSZ) thermal barrier coatings (TBCs) were deposited by atmospheric plasma spraying (APS) on NiCoCrAlY-coated Inconel 738LC substrates. The thermal shock behavior was investigated by quenching the samples in water with temperature of 20-25°C from 950°C. To study of failure mechanism results from thermal cycling, microstructural evaluation using scanning electron microscope (SEM), elemental analysis using energy dispersive spectroscopy (EDS) and phasic analysis using x-ray diffractometry (XRD) were done. The results revealed that failure of the TBC system was due to the spallation of ceramic top coat. Thermal mismatch stress was the major factor of TBC failure in thermal shock test.


2007 ◽  
Vol 561-565 ◽  
pp. 1777-1780
Author(s):  
Wei Zhi Yao ◽  
Shu Xiang Song ◽  
Zhang Jian Zhou ◽  
Wei Wei Cong ◽  
Chang Chun Ge

Molybdenum has many prominent properties, such as high melting point, good thermal properties, and low erosion rate and so on, which make it promising candidate materials for plasma facing materials in the next fusion reactor. In this paper, Molybdenum coatings were deposited onto the oxygen-free copper substrates by atmospheric plasma spraying. The spraying parameters had been carefully selected. Different interlayers were induced between the substrate and the coating. SEM and XRD were used to investigate the photographs and compositions of these coatings. The micro-hardness and bonding strength were also tested. Thermal behaviors of the coatings were evaluated by thermal shock tests. The coatings with interlayers showed better resistance of thermal shock but lower bonding strength compared to coatings that without interlayers.


Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 170
Author(s):  
Songqiang Huang ◽  
Jingzhong Zhou ◽  
Kuoteng Sun ◽  
Hailiang Yang ◽  
Weichen Cai ◽  
...  

Nickel-based alloys are commonly used as protective coating materials for surface protection applications owing to their superior resistance to corrosion, wear and high-temperature oxidation. It is urgent to study the fundamental mechanism between the structure and corrosion properties of the Nickel-base composite coatings. This paper, therefore, focuses on clarifying the mechanisms of the microstructure influencing the acid corrosion and mechanical characteristics of the as-sprayed NiCrBSi coating and post-heat-treated coating. The formation mechanisms of the amorphous phase of flat particles during the plasma spray process were studied by using X-ray diffraction analysis, Raman spectroscopy and confocal laser scanning microscope at first. Then the evolutionary process of the corrosion structure and phase of the coating in the accelerated corrosion experiment is directly visualized by using scanning electron microscopy and energy spectrum analysis. The mechanical properties of the amorphous NiCrBSi coatings are lastly measured by microhardness and friction wear tests. The critical phenomena and results help to elucidate the relative influence of the surface features of atmospheric plasma sprayed coatings on acid corrosion responses and wear resistance, aiming at contributing to the development of a protective technique for electrical engineering.


Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1268
Author(s):  
Yun Wang ◽  
Weichao Wan ◽  
Junhong Mao ◽  
Lihui Tian ◽  
Ruitao Li

In this study, atmospheric plasma spray was employed to deposit TiO2–SiAlON ceramic coating on 316 stainless steel. The phases and microstructure of the ceramic coating were investigated. Additionally, comparative studies on the tribological performances of the substrate and the ceramic coating, under both dry and starved lubrication conditions, were carried out. The SiAlON phase was preserved, while partial TiO2 anatase was transformed to rutile phase. The wear rate of the coating was roughly 1/3 of that of the substrate under both conditions. The wear mechanisms of the ceramic coating were surface fracture and abrasive wear in both cases, and the coating under starved lubrication underwent less abrasion. The pores in the coating served as micro-reservoirs, forming an oil layer on the mating surface, and improving tribological properties during sliding.


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