Fabrication and Evaluation of Plasma-Sprayed Molybdenum for Plasma Facing Materials

2007 ◽  
Vol 561-565 ◽  
pp. 1777-1780
Author(s):  
Wei Zhi Yao ◽  
Shu Xiang Song ◽  
Zhang Jian Zhou ◽  
Wei Wei Cong ◽  
Chang Chun Ge
Keyword(s):  
Thermal Shock ◽  
Bonding Strength ◽  
Fusion Reactor ◽  
Atmospheric Plasma ◽  
Micro Hardness ◽  
High Melting Point ◽  
Promising Candidate ◽  
Spraying Parameters ◽  
Plasma Facing Materials ◽  
Plasma Sprayed

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.

Study on the Plasma-Sprayed Molybdenum as Plasma Facing Materials in Fusion Reactor

2008 ◽  
Vol 373-374 ◽  
pp. 81-84 ◽  
Author(s):  
Wei Zhi Yao ◽  
Shu Xiang Song ◽  
Zhang Jian Zhou ◽  
Wei Wei Cong ◽  
Y. Ma ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Bonding Strength ◽  
Room Temperature ◽  
Fusion Reactor ◽  
Atmospheric Plasma ◽  
High Melting Point ◽  
Promising Candidate ◽  
Plasma Facing Materials ◽  
Quenching Method ◽  
Plasma Sprayed

Molybdenum has many prominent properties, such as high melting point, good thermal properties, low erosion rate and so on, which make it promising candidate materials for plasma facing materials in the next fusion reactor. In the present work, molybdenum coatings were deposited onto the oxygen-free copper substrates by atmospheric plasma spraying. Different interlayers were introduced between the coatings and substrates. SEM, EDS and XRD were used to investigate the photographs and compositions of these coatings. The bonding strength of the coatings was tested to investigate the effect of interlayers on adhesion of the coatings at room temperature and it was found that the coating without interlayers showed the highest bonding strength. Water quenching method was used to evaluate the adhesion of the coatings under thermal cycling conditions and the results showed that the molybdenum coating with two interlayers possessed of the highest resistance of thermal cycling wrack.

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.

scholarly journals Porosity and Its Significance in Plasma-Sprayed Coatings

Coatings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 460 ◽  
Author(s):  
John Gerald Odhiambo ◽  
WenGe Li ◽  
YuanTao Zhao ◽  
ChengLong Li
Keyword(s):  
Working Environment ◽  
Atmospheric Plasma ◽  
Formation Mechanisms ◽  
Multilayer Coatings ◽  
Oxide Coatings ◽  
Spraying Parameters ◽  
Plasma Sprayed Coatings ◽  
Sprayed Coating ◽  
Plasma Sprayed ◽  
Sprayed Coatings

Porosity in plasma-sprayed coatings is vital for most engineering applications. Porosity has its merits and demerits depending on the functionality of the coating and the immediate working environment. Consequently, the formation mechanisms and development of porosity have been extensively explored to find out modes of controlling porosity in plasma-sprayed coatings. In this work, a comprehensive review of porosity on plasma-sprayed coatings is established. The formation and development of porosity on plasma-sprayed coatings are governed by set spraying parameters. Optimized set spraying parameters have been used to achieve the most favorable coatings with minimum defects. Even with the optimized set spraying parameters, defects like porosity still occur. Here, we discuss other ways that can be used to control porosity in plasma-sprayed coating with emphasis to atmospheric plasma-sprayed chromium oxide coatings. Techniques like multilayer coatings, nanostructured coatings, doping with rare earth elements, laser surface re-melting and a combination of the above methods have been suggested in adjusting porosity. The influences of porosity on microstructure, properties of plasma-sprayed coatings and the measurement methods of porosity have also been reviewed.

Effects of CeO2 on the microstructure and tribological properties of atmospheric plasma-sprayed Cr2O3-TiO2 coatings

2019 ◽  
Vol 72 (3) ◽  
pp. 341-347 ◽  
Author(s):  
Qingjun Ding ◽  
Gai Zhao
Keyword(s):  
Tribological Properties ◽  
Design Methodology ◽  
Solution Structure ◽  
Adhesive Wear ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Micro Hardness ◽  
Properties Of Coatings ◽  
Content Type ◽  
Plasma Sprayed

Purpose The purpose of this paper is to study the mechanism and effect of rare earth oxides on the properties of Cr2O3-TiO2 coating. Design/methodology/approach Cr2O3-TiO2 coatings with different proportion of CeO2 were deposited by atmospheric plasma spraying on aluminum alloy 7005. The mechanical, microstructure and tribological properties were studied. Findings The addition of CeO2 could improve the micro-hardness; decrease porosity, wear rate and surface roughness of the coating; and increase the bonding strength between the coating and substrate. The wear mechanism is a mixture of abrasive and adhesive wear. Originality/value The addition of CeO2 could refine microstructure, and promote the formation of solid solution structure, and then affect the properties of coatings.

Development of Functionally Graded Coating Based Plasma Facing Materials for Fusion Reactor

2010 ◽  
Vol 63 ◽  
pp. 383-391
Author(s):  
Chang Chun Ge ◽  
Shuang Quan Guo ◽  
Yun Biao Feng ◽  
Zhang Jian Zhou ◽  
Juan Du ◽  
...  
Keyword(s):  
Heat Flux ◽  
Plasma Spray ◽  
Vapor Deposition ◽  
Fusion Reactor ◽  
High Heat ◽  
Functionally Graded ◽  
Atmospheric Plasma ◽  
High Heat Flux ◽  
Tungsten Coating ◽  
Plasma Facing Materials

Different coating technologies, such as plasma spray (PS), physical vapor deposition (PVD) and chemical vapor deposition (CVD), which can fabricate the PFM and join it to heat sink materials simultaneously, were applied for the fabrication of plasma facing materials (PFM) in fusion reactor. In the Institute of Nuclear Materials, University of Science and Technology Beijing (USTB), the concept of functionally graded materials (FGM) was adopted to fabricate coatings for effectively alleviating the thermal stress generated between coatings and the substrate materials under high heat flux loading (5~20 MW/m2). In the last several years, functionally graded coatings, including B4C/Cu, W/Cu and Mo/Cu systems were successfully fabricated by atmospheric plasma spray (APS). Characterization of coatings was performed in order to assess microstructure, mechanical properties and high heat flux properties of the FGM coatings. Furthermore, a high thick tungsten coating with 4 mm on copper – chromium - zirconium (Cu, Cr, Zr) alloy substrates was fabricated by APS. The porosity of the coating is less than 2% while mean tensile strength of the coating is about 7 MPa. However, the content of oxygen in the coating is about 6 wt% by energy dispersive spectrum (EDS) analysis, thus further optimization is necessary.

Study on Interfacial Characterization and Mechanical Properties of Plasma-Sprayed Tungsten Coatings

2007 ◽  
Vol 546-549 ◽  
pp. 1809-1812
Author(s):  
Shu Xiang Song ◽  
Zhang Jian Zhou ◽  
Juan Du ◽  
Chang Chun Ge
Keyword(s):  
Mechanical Properties ◽  
Bonding Strength ◽  
The Other ◽  
Inert Gases ◽  
Tungsten Coating ◽  
Hardness Distribution ◽  
Thickness Direction ◽  
Micro Hardness ◽  
Plasma Sprayed ◽  
Vickers Micro Hardness

Tungsten has the highest melting point among all metal, which makes it withstand thermal shock and erosion in high temperature environments. In this study, Tungsten coatings were sprayed onto the oxygen-free copper substrates by plasma spraying using inert gases protection. XRD, SEM and EDS were used to identify the phases, morphologies and compositions of the coatings. Vickers micro-hardness and bonding strength of the tungsten coatings were also measured. The results revealed that the hardness distribution of the tungsten coatings was different along the thickness direction. The tungsten coating without any interlayer showed higher bonding strength than that of the other two coatings with NiCrAl and W/Cu interlayers, respectively.

A XPS Study of Atmospheric Plasma Sprayed TiB2 Coatings

2008 ◽  
Vol 368-372 ◽  
pp. 1347-1350 ◽  
Author(s):  
Jun Hu Liu ◽  
Bart Blanpain ◽  
Patrick Wollants
Keyword(s):  
Lattice Oxygen ◽  
Atmospheric Plasma ◽  
Peak Fitting ◽  
Spraying Parameters ◽  
Five Elements ◽  
Xps Study ◽  
Plasma Sprayed

TiB2 coatings were plasma sprayed in air and were studied by XPS. There are five elements in the top surface of the studied coatings, namely, B, C, N, O and Ti. Oxygen pick-up in the coatings results in formation of oxides of boron and titanium. Nitrogen was shown to exist in N-Ti and O-N-Ti in the coating. Depending on the spraying parameters, mono-boride as well as di-boride was also detected in the studied coatings. With careful peak fitting it was shown that oxygen may exist in the coating as dissolved atomic O in addition to as lattice oxygen in the oxide of boron and titanium.

Investigation of Thermal Shock Behavior of Plasma-Sprayed NiCoCrAlY/YSZ Thermal Barrier Coatings

2012 ◽  
Vol 472-475 ◽  
pp. 246-250 ◽  
Author(s):  
Hossein Jamali ◽  
Reza Mozafarinia ◽  
Reza Shoja Razavi ◽  
Raheleh Ahmadi Pidani
Keyword(s):  
Thermal Shock ◽  
Thermal Barrier Coatings ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Thermal Shock Test ◽  
Barrier Coatings ◽  
Microstructural Evaluation ◽  
Mismatch Stress ◽  
Thermal Shock Behavior ◽  
Plasma Sprayed

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.

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