Oxidation Behaviors of Pure Ti Thermal Plasma Spray Coated Mo-Si-B Alloys

2011 ◽  
Vol 695 ◽  
pp. 365-368 ◽  
Author(s):  
Young Ho Song ◽  
Joon Sik Park ◽  
Jeong Min Kim ◽  
Seong Hoon Yi
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Alloy System ◽  
Underlying Mechanism ◽  
High Temperature Strength ◽  
Air Atmosphere ◽  
Elemental Component ◽  
Ti Powder ◽  
Poor Oxidation Resistance ◽  
Oxidation Behaviors

Mo-Si-B alloys have been received an attention due to the high temperature strength and phase stability. However, the nature of poor oxidation resistance often limits the application of the alloy system. The unstable MoO3 phase is naturally produced when the alloys were exposed at low and /or high temperature in an air atmosphere. In order to resolve the poor oxidation resistance of the alloy system, several attempts have been made via surface coatings and/or component additions. In this study, the oxidation behaviors of the Ti powder thermal spray coated Mo-Si-B alloys have been investigated in order to identify the underlying mechanism for the effect of precursor Ti coatings on Mo-Si-B alloys. The oxidation tests performed at 1100 °C show that the Ti powder was tightly bonded and reacted with the surface of the substrate, and TiO2 layer was formed at the outer surface of the coated Ti layer as a result of oxidation exposure. The oxidation behaviors of pure elemental component coated Mo-Si-B alloys have been discussed in terms of microstructural observations during oxidation tests.

Oxidation Behaviors of Two and Three Phase Mo-Si-B Alloys via Si Pack Cementation

2012 ◽  
Vol 706-709 ◽  
pp. 2446-2449
Author(s):  
Young Ho Song ◽  
Joon Sik Park ◽  
Jeong Min Kim ◽  
Seong Hoon Yi
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Alloy System ◽  
Underlying Mechanism ◽  
High Temperature Strength ◽  
Three Phase ◽  
Phase Combination ◽  
Temperature Exposure ◽  
Poor Oxidation Resistance ◽  
Oxidation Behaviors

Mo-Si-B alloys have been received an attention due to the high temperature strength and phase stability. However, the nature of poor oxidation resistance often limits the application of the alloy system. In order to resolve the poor oxidation resistance of the alloy system, in this study, the oxidation behaviors of Si diffusion coated Mo-Si-B alloys have been investigated in order to identify the underlying mechanism for the effect of the constituent of the phase combination of Mo-Si-B alloys. The oxidation tests performed at 1100 °C show that the produced MoSi2 phase, as a result of the coatings, give an excellent oxidation resistance at prolonged high temperature exposure in air. The oxidation behaviors of uncoated and Si coated Mo-Si-B alloys have been discussed in terms of microstructural observations during oxidation tests.

Combined Effect of Mg and Ca on Oxidation Behaviors of Zn–Mg Based Alloys Containing a Trace of Ca at High Temperature

2021 ◽  
Vol 21 (3) ◽  
pp. 2063-2066
Author(s):  
Seong-Ho Ha ◽  
Bong-Hwan Kim ◽  
Young-Ok Yoon ◽  
Hyun-Kyu Lim ◽  
Shae K. Kim
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Intermetallic Phase ◽  
Combined Effect ◽  
Rapid Weight Gain ◽  
Temperature Oxidation ◽  
Air Atmosphere ◽  
Behavior Observation ◽  
Constituent Elements ◽  
Oxidation Behaviors

In this study, the combined effect of Mg and Ca on the high temperature oxidation behaviors of Zn–Mg based alloys containing trace Ca was investigated. Phase diagrams for the oxygen partial pressure versus contents of constituent elements were conducted on the basis of thermodynamic calculations to predict oxide scale behavior. Observation of Zn-1/3/5 mass%Mg alloys showed the distribution of a Zn–Zn11Mg2 eutectic phase after primary formation. As-cast microstructures of the Ca-containing alloys included the formation of a Ca-based intermetallic phase. The change in oxidation resistance with variation of the Mg and Ca contents was experimentally examined via thermogravimetric analysis (TGA). The addition of trace Ca led to the formation of Zn13Ca and a CaO/MgO mixed oxide layer on the surface at 460 °C. After TGA at 460 °C under air atmosphere for 1 h, the Ca-free alloys showed rapid weight gain by oxidation, whereas the oxidation resistance of the Ca-added alloys was substantially increased.

Phase transformation and layer evolution in molybdenum disilicide-silicon carbide nanolayered coatings

1994 ◽  
Vol 52 ◽  
pp. 538-539
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J.-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Matrix Material ◽  
Molybdenum Disilicide ◽  
High Temperature Strength ◽  
Cross Sectional ◽  
Good Oxidation Resistance ◽  
Structural Applications

MoSi2 is a potential matrix material for high temperature structural composites due to its high melting temperature and good oxidation resistance at elevated temperatures. The two major drawbacksfor structural applications are inadequate high temperature strength and poor low temperature ductility. The search for appropriate composite additions has been the focus of extensive investigations in recent years. The addition of SiC in a nanolayered configuration was shown to exhibit superior oxidation resistance and significant hardness increase through annealing at 500°C. One potential application of MoSi2- SiC multilayers is for high temperature coatings, where structural stability ofthe layering is of major concern. In this study, we have systematically investigated both the evolution of phases and the stability of layers by varying the heat treating conditions.Alternating layers of MoSi2 and SiC were synthesized by DC-magnetron and rf-diode sputtering respectively. Cross-sectional transmission electron microscopy (XTEM) was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures.

HASTELLOY ALLOY X

Alloy Digest ◽  
1954 ◽  
Vol 3 (12) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
High Temperatures ◽  
Heat Treating ◽  
Operating Conditions ◽  
Molybdenum Alloy ◽  
High Temperature Strength ◽  
Nickel Chromium

Abstract HASTELLOY Alloy X is a nickel-chromium-iron-molybdenum alloy recommended for high-temperature applications. It has outstanding oxidation resistance at high temperatures under most operating conditions, and good high-temperature strength. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on forming, heat treating, and machining. Filing Code: Ni-14. Producer or source: Haynes Stellite Company.

AK STEEL 441

Alloy Digest ◽  
2006 ◽  
Vol 55 (6) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Ferritic Stainless Steel ◽  
High Temperature Oxidation ◽  
High Temperature Strength ◽  
Temperature Oxidation ◽  
Temperature Performance

Abstract AK Steel 441 has good high-temperature strength, an equiaxed microstructure, and good high-temperature oxidation resistance. The alloy is a niobium-bearing ferritic stainless steel. This datasheet provides information on composition, hardness, and tensile properties as well as deformation. It also includes information on high temperature performance and corrosion resistance as well as forming and joining. Filing Code: SS-965. Producer or source: AK Steel.

KUBOTA HK40 and HK50

Alloy Digest ◽  
2007 ◽  
Vol 56 (10) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Carbon Content ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Heat Treating ◽  
Industrial Applications ◽  
High Temperature Strength ◽  
Ni Alloys ◽  
Moderately High Temperature

Abstract Kubota alloys HK40 and HK50 are austenitic Fe-Cr-Ni alloys that have been standard heat-resistant materials for more than four decades. With moderately high temperature strength, oxidation resistance, and carburization resistance the alloys are used in a wide variety of industrial applications. HK 50 has slightly higher carbon content. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on casting, heat treating, machining, and joining. Filing Code: SS-998. Producer or source: Kubota Metal Corporation, Fahramet Division.

Permodur 4742

Alloy Digest ◽  
2018 ◽  
Vol 67 (4) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Heat Treating ◽  
High Temperature Strength ◽  
Aluminum Addition

Abstract Permodur 4742 is an alloy with good high temperature strength and oxidation resistance and has an aluminum addition. The alloy is also called Ferrotherm 4742 at Edelstahlwerke Südwestfalen GmbH. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: SS-1284. Producer or source: Deutsche Edelstahlwerke.

High Temperature Stability of MGCs Gas Turbine Components in Air and Combustion Gas Flow Environments

2004 ◽  
Author(s):  
Narihito Nakagawa ◽  
Hideki Ohtsubo ◽  
Kohji Shibata ◽  
Atsuyuki Mitani ◽  
Kazutoshi Shimizu ◽  
...  
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Gas Flow ◽  
Temperature Stability ◽  
High Temperature Strength ◽  
High Temperature Stability ◽  
Combustion Gas ◽  
Air Atmosphere ◽  
Low Nox Emission ◽  
Very High

Melt growth composites (MGCs) have a unique microstructure, in which continuous networks of single-crystal phases interpenetrate without grain boundaries. Therefore, the MGCs have excellent high-temperature strength characteristics, creep resistance, oxidation resistance and thermal stability in an air atmosphere at very high temperature. To achieve ultra-high thermal efficiency and low NOx emission for gas turbine systems, non-cooled turbine nozzle vanes and heat shield panels of combustor liners has been fabricated on an experimental basis. These components are thermally stable after heat treatment at 1700°C for 1000 hours in an air atmosphere. In addition, we have just started the exposure tests to evaluate the influence of combustion gas flow environment on MGCs.

The Investigation of the Interdiffusion Barrier in TiAl/MCrAlY System

2010 ◽  
Vol 654-656 ◽  
pp. 1920-1923 ◽  
Author(s):  
Wen Wang ◽  
Yu Xian Cheng ◽  
Sheng Long Zhu ◽  
Fu Hui Wang ◽  
Li Xin
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Diffusion Barrier ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
The Poor ◽  
Structural Applications ◽  
Nicraly Coating ◽  
Overlay Coatings ◽  
Poor Oxidation Resistance

TiAl based alloys are promising candidates for structural applications at high temperature. However, the poor oxidation resistance above 800oC obviously restrains their applications. Although NiCrAlY overlay coatings can remarkably improve the high temperature oxidation resistance of TiAl, serious inward diffusion of Ni from the coating to the substrate occurs which could reduce the lifetime of the coating/substrate system. Apparently, the development of interdiffusion barrier could overcome the disadvantage of the NiCrAlY/TiAl system. In this work, Ta, TiN and Cr2O3 interlayers were deposited between NiCrAlY coating and γ-TiAl substrate as diffusion barrier (DB). The interdiffusion behavior of the TiAl/DB/NiCrAlY system was investigated at 1000°C. The results showed that the metallic and nitride interlayers cannot retard the interdiffusion of Ni effectively. As an active diffusion barrier, the oxide interlayer obviously suppressed the inward diffusion of Ni from the coating to the substrate by the formation of alumina-rich layers at both the TiAl/DB and DB/NiCrAlY interfaces.

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