scholarly journals Hafnium Carbide Coatings Deposited by Suspension Vacuum Plasma Spraying for Ultra-High-Temperature Oxidation Barrier on Carbon Composites

2021 ◽  
Vol 30 (1) ◽  
pp. 21-24
Author(s):  
Yeon Woo Yoo ◽  
Uk Hee Nam ◽  
Yeontae Kim ◽  
Hyung Ik Lee ◽  
Jong Kyoo Park ◽  
...  
Keyword(s):  
High Temperature ◽  
Plasma Spraying ◽  
High Temperature Oxidation ◽  
Carbon Composites ◽  
Hafnium Carbide ◽  
Vacuum Plasma Spraying ◽  
Temperature Oxidation ◽  
Vacuum Plasma ◽  
Carbide Coatings ◽  
Ultra High Temperature

scholarly journals Microstructure and Mechanical Properties of Vacuum Plasma Sprayed HfC, TiC, and HfC/TiC Ultra-High-Temperature Ceramic Coatings

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 124
Author(s):  
Ho Seok Kim ◽  
Bo Ram Kang ◽  
Seong Man Choi
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Single Layer ◽  
Ceramic Coatings ◽  
Hafnium Carbide ◽  
Vacuum Plasma Spraying ◽  
Vacuum Plasma ◽  
Coating Layers ◽  
Hardness Values ◽  
Ultra High Temperature

To improve the oxidation resistance of carbon composites at high temperatures, hafnium carbide (HfC) and titanium carbide (TiC) ultra-high-temperature ceramic coatings were deposited using vacuum plasma spraying. Single-layer HfC and TiC coatings and multilayer HfC/TiC coatings were fabricated and compared. The microstructure and composition of the fabricated coatings were analyzed using field-emission scanning electron microscopy and energy dispersive X-ray spectroscopy. The coating thicknesses of the HfC and TiC single-layer coatings were 165 µm and 140 µm, respectively, while the thicknesses of the HfC and TiC layers in the HfC/TiC multi-layer coating were 40 µm and 50 µm, respectively. No oxides were observed in any of the coating layers. The porosity was analyzed from cross-sectional images of the coating layers obtained using optical microscopy. Five random areas for each coating layer specimen were analyzed, and average porosity values of approximately 16.8% for the HfC coating and 22.5% for the TiC coating were determined. Furthermore, the mechanical properties of the coating layers were investigated by measuring the hardness of the cross section and surface roughness. The hardness values of the HfC and TiC coatings were 1650.7 HV and 753.6 HV, respectively. The hardness values of the HfC and TiC layers in the multilayer sample were 1563.5 HV and 1059.2 HV, respectively. The roughness values were 5.71 µm for the HfC coating, 4.30 µm for the TiC coating, and 3.32 µm for the HfC/TiC coating.

Vacuum Plasma Spraying of Pre-reacted MoSi2 and SiC-Reinforced MoSi2 Produced by a New Kind of Powder Processing

2000 ◽  
Author(s):  
B. Wielage ◽  
S. Steinhäuser ◽  
G. Reisel ◽  
I. Morgenthal ◽  
R. Scholl
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Plasma Spraying ◽  
Powder Processing ◽  
Protective Coatings ◽  
High Energy ◽  
Vacuum Plasma Spraying ◽  
Temperature Oxidation ◽  
Vacuum Plasma ◽  
Brittle Ductile Transition

Abstract Molybdenum silicides have the potential as protective coatings for high-temperature applications because of their high melting point and their high-temperature oxidation resistance. Reinforcing MoSi2 with SiC shows an improvement of its low toughness at room temperature and low creep resistance at temperatures above the brittle-ductile transition temperature of approximately 700-1000 °C. A new kind of powder processing was used to produce MoSi2 and MoSi2-SiC as a feedstock for thermal spraying. Mixtures of the elemental powders, molybdenum and silicon, were prepared by milling and subsequent heat treatment to get highly dispersed, pre-reacted powders. As high-energy milling equipment, a planetary ball mill was used to prepare the powders. In the case of reinforcement, SiC was mixed to the pre-reacted MoSi2 at the end of the milling process, that means before heat treatment. On these as-milled powders, X-ray diffraction characterization (XRD), scanning electron microscopy (SEM), electron probe micro analysis (EPMA) and determination of the oxygen level were carried out. Vacuum plasma spraying has been used to deposit the powders onto a carbon steel substrate. Evaluated coating characteristics were the microstructure (SEM), phases (XRD), EPMA, oxygen content, microhardness and surface roughness. Tests at high temperatures will be considered in future work.

scholarly journals High temperature oxidation of two- and three-dimensional hafnium carbide and silicon carbide coatings

2014 ◽  
Vol 34 (4) ◽  
pp. 879-887 ◽  
Author(s):  
C. Verdon ◽  
O. Szwedek ◽  
A. Allemand ◽  
S. Jacques ◽  
Y. Le Petitcorps ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
High Temperature Oxidation ◽  
Three Dimensional ◽  
Hafnium Carbide ◽  
Temperature Oxidation ◽  
Carbide Coatings

Ultra-high temperature oxidation of a hafnium carbide-based solid solution ceramic composite

2014 ◽  
Vol 80 ◽  
pp. 402-407 ◽  
Author(s):  
David W. Lipke ◽  
Sergey V. Ushakov ◽  
Alexandra Navrotsky ◽  
Wesley P. Hoffman
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
High Temperature Oxidation ◽  
Ceramic Composite ◽  
Hafnium Carbide ◽  
Temperature Oxidation ◽  
Ultra High Temperature

A novel ultra-high-temperature oxidation protective MoSi2-TaSi2 ceramic coating for tantalum substrate

2019 ◽  
Vol 39 (7) ◽  
pp. 2277-2286 ◽  
Author(s):  
Zhenyang Cai ◽  
Daxu Zhang ◽  
Xinxiang Chen ◽  
Yuntong Huang ◽  
Yuqing Peng ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Ceramic Coating ◽  
Temperature Oxidation ◽  
Ultra High Temperature

Aluminizing Behaviors of Vacuum Plasma Sprayed MCrAlY Coatings

2002 ◽  
Vol 124 (2) ◽  
pp. 270-275 ◽  
Author(s):  
Y. Itoh ◽  
M. Saitoh ◽  
Y. Ishiwata
Keyword(s):  
High Temperature ◽  
Diffusion Rate ◽  
Nickel Content ◽  
Reaction Diffusion ◽  
Vacuum Plasma Spraying ◽  
Temperature Oxidation ◽  
Vacuum Plasma ◽  
Mcraly Coatings ◽  
Heat Treated ◽  
Plasma Sprayed

The objective of this study is aluminide overlay coatings of MCrAlY sprayed by a vacuum plasma spraying (VPS) process for the protection against high-temperature corrosion and oxidation of gas turbine components. Diffusion coating processes have been applied for many years to improve similarly the environmental resistance by enriching the surface of nickel-based superalloys with chromium, aluminum, or silicon element. Recently, aluminizing of MCrAlY coatings is used for improving further the high-temperature oxidation resistance. However, the aluminizing properties of plasma-sprayed MCrAlY coatings, which have an important effect on the coating performance, have not been clarified. In this study, five kinds of plasma-sprayed MCrAlY (CoCrAlY, CoNiCrAlY, CoNiCrAlY+Ta, NiCrAlY, and NiCoCrAlY) coating were selected for pack-aluminizing tests. The as sprayed and the heat-treated (1393 K, 2 h, argon cooled and 1116 K, 24 h, argon cooled) MCrAlY specimens were Al-Cr-Al2O3-NH4Cl pack-aluminized at 1173, 1223, and 1273 K for 5, 10, and 20 h, respectively. The experimental results showed that the aluminizing process formed the aluminum rich layers of NiAl or CoAl phase. It also indicated that the thickness of the aluminum rich layer showed a parabolic time-dependence in all MCrAlY coatings. The order of reaction diffusion rate was NiCoCrAlY=NiCrAlY>CoNiCrAlY>CoNiCrAlY+Ta>CoCrAlY. There was a tendency that the reaction diffusion rate by aluminizing increased with increasing nickel content in the MCrAlY coatings and the reaction diffusion rate of as sprayed MCrAlY coatings is faster than that of the heat-treated MCrAlY coatings.

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